IPAC2022 - List of Keywords (gun)

Paper	Title	Other Keywords	Page
MOPOPT057	Updates in Efforts to Data Science Enabled MeV Ultrafast Electron Diffraction System	electron, network, laser, experiment	397
	S. Biedron, T.B. Bolin, M. Martínez-Ramón, S.I. Sosa Guitron UNM-ECE, Albuquerque, USA M. Babzien, M.G. Fedurin, J.J. Li, M.A. Palmer BNL, Upton, New York, USA S. Biedron UNM-ME, Albuquerque, New Mexico, USA D. Martin, M.E. Papka ANL, Lemont, Illinois, USA
	Funding: Work supported by DOEs EPSCoR award DE-SC0021365, used resources of the Brookhaven National Laboratory’s Accelerator Test Facility and of the Argonne Leadership Computing Facility. MeV ultrafast electron diffraction (MUED) is a pump-probe characterization technique to study ultrafast phenomena in materials with high temporal and spatial resolution. This complex instrument can be advanced into a turn-key, high-throughput tool with the aid of machine learning (ML) mechanisms and high-performance computing. The MUED instrument at the Accelerator Test Facility in Brookhaven National Laboratory was employed to test different ML approaches for both data analysis and control. We characterized different materials using MUED, mainly polycrystalline gold and single crystal Ta2NiS5. Diffraction patterns were acquired in single shot mode and convolutional neural network autoenconder models were evaluated for noise reduction and the reconstruction error was studied to identify anomalous diffraction patterns. Electron beam energy jitter was analyzed from single shot diffraction patterns to be used as a novel diagnostic tool. The MUED beamline was also simulated using VSim to construct a surrogate model for control of beam shape and energy. Progress towards ML-based controls leveraging off Argonne Leadership Computing Facility resources will also be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT057
About •	Received ※ 02 July 2022 — Accepted ※ 26 June 2022 — Issue date ※ 08 July 2022
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MOPOTK003	Absorbed Dose Characteristics for Irradiation Experiments at AREAL 5 MeV Electron Linac	electron, experiment, radiation, simulation	429
	V.G. Khachatryan, Z. Amirkhanyan, H. Davtyan, A. Grigoryan, B. Grigoryan, M. Ivanyan, V.H. Petrosyan, A. Vardanyan, A.S. Yeremyan CANDLE SRI, Yerevan, Armenia A. Grigoryan YSU, Yerevan, Armenia
	Existing electron photogun facility at the CANDLE SRI currently can provide electron beam with the energy up to 5 MeV. The beam is being used as an irradiation source in the number of material science and life science experiments. Performed beam particle tracking simulations along with intensive application of the beam diagnostic instruments (bending magnet, YAG stations, Faraday cups) allow control of the experimental samples’ irradiation parameters, particularly exposure times for given dose as well as absorbed dose spatial distribution. Direct application of the electron beam for the irradiation experiments allows achievement of high absorbed dose. For the calculation of the irradiation parameters of the experimental samples’ particle transport simulation results should be combined with the beam current measurements by Faraday Cup (FC). Dose measurements and the comparison with numerical simulations using various initial parameters (Transverse size, divergence and energy spread) permit to pin down their actual values.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK003
About •	Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
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MOPOTK022	A Design Study of Injector System for Synchrotron Light Source	linac, electron, cavity, simulation	485
	C. Kim, E.-S. Kim, C.S. Park KUS, Sejong, Republic of Korea
	This work presents a design study of a 200 MeV electron linear accelerator consisting of an electron gun, bunchers, and accelerator structures. We aimed to design the linac with low emittance and low energy spread. A coasting beam from a thermionic electron gun is bunched using a series of buncher cavities: sub-harmonic buncher (SHB), a pre-buncher (PB), and a Buncher. The bunched beam is then accelerated up to 200 MeV with 4 cascaded accelerating structures. The SHB was designed with one-cell standing wave structure for improving the bunching efficiency. The two types of the 500 MHz SHB were considered: elliptical and coupled-cavity linac types. We also investigated constant-gradient and constant-impedance types of 3 GHz multi-cell traveling wave resonators for following buncher cavities and accelerating structures. Depending on the type, geometries of each traveling wave structure (TWS) cavity were determined, and then the electromagnetic fields were calculated. RF powers and phases of each cavity along this linac system were optimized using beam dynamics simulation. Furthermore, the beam distributions in the transverse direction are adjusted using solenoid magnets in the lowenergy section as well as quad triplets in the high-energy section.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK022
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 17 June 2022
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MOPOTK023	Beam Dynamics Studies on the 50 MeV Electron Linear Accelerator for Ultra-High Dose Rates	electron, acceleration, cavity, cathode	489
	Y. Lee, C. Kim, E.-S. Kim, C.S. Park KUS, Sejong, Republic of Korea H.-S. Lee, H.S. Shin VITZRONEXTECH, Ansan-si, Gyeonggi-do, Republic of Korea
	Electron beams with ultra-high dose rates (>40 Gy/s), which enable effective radiotherapy to act on deep-seated tumors in less than a second, can be generated by linear accelerators. To successfully achieve FLASH radiotherapy, we have performed the 50 MeV linear accelerator design studies. The designed electron accelerator consists of a thermionic electron gun, sub-harmonic buncher, buncher and 2.856 GHz traveling wave structure. In this report the design layout and particle tracking simulation results of the 50 MeV electron linac with high beam current are presented in detail. FLASH radiotherapy
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK023
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022
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MOPOTK051	Modeling a Nb₃Sn Cryounit in GPT at UITF	cavity, SRF, simulation, electron	576
	S. Pokharel, G.A. Krafft ODU, Norfolk, Virginia, USA A.S. Hofler, G.A. Krafft JLab, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. Nb₃Sn is a prospective material for future superconducting RF (SRF) accelerator cavities. The material can achieve higher quality factors, higher temperature operation and potentially higher accelerating gradients (E_acc 96 MV/m) compared to conventional niobium. In this work, we performed modeling of the Upgraded Injector Test Facility (UITF) at Jefferson Lab utilizing newly constructed Nb₃Sn cavities. We studied the effects of the buncher cavity and varied the gun voltages from 200-500 keV. We have calibrated and optimized the SRF cavity gradients and phases for the Nb₃Sn five-cell cavities energy gains with the framework of General Particle Tracer (GPT). Our calculations show the beam goes cleanly through the unit. There is full energy gain out of the second SRF cavity but not from the first SRF cavity due to non-relativistic phase shifts.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK051
About •	Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 19 June 2022
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MOPOTK052	CEBAF Injector Model for K_L Beam Conditions	laser, simulation, experiment, cathode	580
	S. Pokharel, G.A. Krafft ODU, Norfolk, Virginia, USA M.W. Bruker, J.M. Grames, A.S. Hofler, R. Kazimi, G.A. Krafft, S. Zhang JLab, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. The Jefferson Lab KL experiment will run at the Continuous Electron Beam Accelerator Facility with a much lower bunch repetition rate (7.80 or 15.59 MHz) than nominally used (249.5 or 499 MHz). While the proposed average current of 2.5 - 5.0 muA is relatively low compared to the maximum CEBAF current of approximately 180 muA, the corresponding bunch charge is atypically high for CEBAF injector operation. In this work, we investigated the evolution and transmission of low-rep-rate, high-bunch-charge (0.32 to 0.64 pC) beams through the CEBAF injector. Using the commercial software General Particle Tracer, we have simulated and analyzed the beam characteristics for both values of bunch charge. We performed these simulations with the existing injector using a 130 kV gun voltage. We have calculated and measured the transmission as a function of the photocathode laser spot size and pulse length. We report on the findings of these simulations and optimum parameters for operating the experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK052
About •	Received ※ 07 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 26 June 2022
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MOPOMS001	Progress on Development of AXSIS: A Femtosecond THz-Driven MeV Accelerator and keV X-Ray Source	electron, acceleration, linac, laser	621
	N.H. Matlis, M. Fakhari, F.X. Kärtner, T. Kroh, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang CFEL, Hamburg, Germany R. Bazrafshan, F.X. Kärtner, T. Rohwer Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany R. Bazrafshan, M. Vahdani University of Hamburg, Hamburg, Germany M. Fakhari, D. Zhang DESY, Hamburg, Germany F.X. Kärtner, T. Kroh The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
	Funding: This work was supported by KA908-12/1 of the Deutsche Forschungsgemeinschaft and by the ERC under the European Union’s Seventh Framework Program (FP7/2007-2013) through Synergy Grant AXSIS (609920). We report on the design and progress in implementing a THz-driven relativistic electron accelerator and associated X-ray source, the AXSIS Facility at DESY. We have developed a full layout of the machine based on a THz gun followed by a multi-cycle dielectric loaded metal waveguide THz linear accelerator to generate 20 MeV level, 10 fs electron bunches. The required THz pulse energies are on the mJ-level for the gun and multi-10-mJ-level for the THz linac. Customized laser technologies have been developed allowing for the generation of these pulses up to 1 kHz repetition rate. The generated electron bunches are then focused into a counter propagating optical pulse ’optical undulator’ to generate X-rays in the 6-7 keV range. We will discuss the overall layout of the machine, status of its implementation and technical challenges in the different components as well as diagnostics of this new type of accelerator and X-ray source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS001
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
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MOPOMS003	Single-Sided Pumped Compact Terahertz Driven Booster Accelerator	electron, booster, acceleration, experiment	625
	T. Kroh, R. Bazrafshan, F.X. Kärtner, N.H. Matlis Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany M. Fakhari, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang CFEL, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany K. Kawase JAEA, Kizugawa, Japan
	Funding: European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) through the Synergy Grant ’Frontiers in Attosecond X-ray Science: Imaging and Spectroscopy’ (609920). Scaling the RF-accelerator concept to terahertz (THz) frequencies brings several compelling advantages, including compactness, intrinsic timing between the photoemission and driving field sources, and high field gradients associated with the short THz wavelength and high breakdown threshold. Recent demonstrations of such THz powered accelerators relied on two counter-propagating single-cycle THz pulses. However, to achieve high energy gains in the acceleration process high energy THz pulses are needed which in turn require complex optical setups. Here, we present on the development of a matchbox sized multi-layered accelerator designed to boost the 50 keV output of a DC electron gun to energies of ~400 keV that only requires a single THz pulse to be powered. An integrated tunable mirror inside the structure interferes the front of the driving THz pulse with its rear part such that the field in the interaction region is optimized for efficient acceleration. This reduces the complexity of the required optical setup. Such a compact booster accelerator is very promising as electron source in ultrafast electron diffraction experiments and as booster stage prior to THz based LINACs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS003
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022
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MOPOMS005	Start-to-End Simulations of a THz-Driven ICS Source	electron, linac, simulation, photon	631
	M. Fakhari, Y.-K. Kan DESY, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany F.X. Kärtner Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany N.H. Matlis, M. Vahdani CFEL, Hamburg, Germany M. Vahdani University of Hamburg, Hamburg, Germany
	We present start-to-end simulations for a fully THz-driven table-top X-ray source. A dielectric-loaded metallic cavity operating at its Higher Order Mode accelerates 1 PC photo emitted electron bunch up to 430 keV kinetic energy. The output beam of the gun is injected into a dielectric-loaded waveguide where phase velocity of the traveling wave is adjusted in such a way that electrons see an accelerating field all the way along the tube resulting to an 18.5-MeV output beam which is then transported to an inverse Compton scattering (ICS) stage. The injection phase of the electrons can be tuned to introduce a negative energy chirp to the electron bunch leading to a ballistic bunch compression after the linac. In addition, a set of permanent magnet quadrupoles is designed to focus the beam at the ICS interaction point where the electron beam scatters off a 250-mJ, 0.5ps, 1-µm laser beam and generates an X-ray beam with 2.6x10⁷ photons per shot containing photon energies 2keV< Eph <8keV in a beam with 50 mrad half opening angle. The required terahertz waves to power the gun and linac are 550-ps pulses at 300 GHz containing 5 mJ and 23 mJ energies respectively with 1 kHz repetition rate.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS005
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022
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MOPOMS013	Toward Emittance Measurements at 11.7 GHz Short-Pulse High-Gradient RF Gun	linac, emittance, GUI, experiment	649
	S.V. Kuzikov, C.-J. Jing, E.W. Knight Euclid TechLabs, Solon, Ohio, USA G. Chen, C.-J. Jing, P. Piot, E.E. Wisniewski ANL, Lemont, Illinois, USA C.-J. Jing Euclid Beamlabs, Bolingbrook, USA P. Piot Fermilab, Batavia, Illinois, USA P. Piot, W.H. Tan Northern Illinois University, DeKalb, Illinois, USA
	Funding: This project is supported with DoE SBIR Phase II Grant #DE-SC0018709. A short pulse high gradient RF gun has been recently tested at Argonne Wakefield Accelerator (AWA) facility. The carried-out test showed that the 1,5-cell gun was able to inject 3 MeV, up to 100 pC bunches at room tem-perature being fed by 9 ns up to 300 MW 11.7 GHz puls-es. The cathode field was as high as about 400 MV/m. So high field is aimed to mitigate repealing Coulomb forces substantially. In accordance with simulations the emit-tance could be as low as less than 0.2 mcm. To obtain so low emittance in the experiment, the gun is assumed to be equipped with a downstream linac to be fed from the same power extractor as the gun itself. Here we report design of the RF power distribution system splitting RF power among the gun and the linac, results of low-power tests, and emittance measurement plans for upcoming new experiment at AWA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS013
About •	Received ※ 01 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 01 July 2022
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MOPOMS014	Commissioning of a High-Gradient X-Band RF Gun Powered by Short RF Pulses from a Wakefield Accelerator	electron, laser, cathode, MMI	652
	W.H. Tan, X. Lu, P. Piot Northern Illinois University, DeKalb, Illinois, USA S.P. Antipov, C.-J. Jing, E.W. Knight, S.V. Kuzikov Euclid TechLabs, Solon, Ohio, USA D.S. Doran, G. Ha, C.-J. Jing, W. Liu, X. Lu, P. Piot, P. Piot, J.G. Power, J. Shao, C. Whiteford, E.E. Wisniewski ANL, Lemont, Illinois, USA
	Funding: This work is supported by the U.S. DOE, under award No. DE-SC0018656 to NIU, DOE SBIR grant No DE-SC0018709 at Euclid Techlabs LLC, and contract No. DE-AC02-06CH11357 with ANL. A high-gradient X-band (11.7-GHz) photoinjector developed by Euclid Techlabs, was recently commissioned at the Argonne Wakefield Accelerator (AWA). The system comprises a 1+1/2-cell RF gun powered by short RF pulses generated as a train of high-charge bunches from the AWA accelerator passes through a slow-wave power extraction and transfer structure. The RF photoinjector was reliably operating with electric fields in excess of 300 MV/m on the photocathode surface free of breakdown and with an insignificant dark-current level. We report on the RF-gun setup, commissioning, and the associated beam generation via photoemission.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS014
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 19 June 2022
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MOPOMS018	Tungsten Electron Emitter (TE²) with Direct Heated Cathode by Plasma Stream	cathode, electron, plasma, ion-source	667
	K.I. Thoma, M. Droba, T. Dönges, O. Meusel, H. Podlech, K. Schulte-Urlichs IAP, Frankfurt am Main, Germany K. Schulte-Urlichs, K.I. Thoma GSI, Darmstadt, Germany
	At Goethe-University, a novel concept of heating metallic cathodes is currently under investigation. In the scope of the ARIES collaboration WP16, an RF-modulated electron gun was developed and manufactured for application in electron lenses for space charge compensation. The goal of this project is to increase the intensity of primary beams, especially in low energy booster synchrotrons like the SIS18 and SIS100 at GSI/FAIR or the SPS at CERN. The gun was designed to produce electron currents of 10 A at extraction voltages of 30 kV. The tungsten electron emitter (TE²) and the grid electrode were designed and manufactured to be integrated in the extractor of the original volume type ion source. Significant effort was put into a robust and flexible design with highly reliable key components. The cathode is heated by a plasma stream generated in the plasma chamber of the source. Different heating options of the cathode are currently being studied. This contribution presents the working principles of the electron gun and first measurements results of cathode heating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS018
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 26 June 2022
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MOPOMS019	The New SPARC_LAB RF Photo-Injector	operation, solenoid, vacuum, quadrupole	671
	D. Alesini, M.P. Anania, M. Bellaveglia, A. Biagioni, F. Cardelli, G. Costa, M. Del Franco, G. Di Pirro, L. Faillace, M. Ferrario, G. Franzini, A. Gallo, A. Giribono, L. Piersanti, L. Sabbatini, A. Stella, A. Vannozzi INFN/LNF, Frascati, Italy A. Battisti, E. Chiadroni, G. Di Raddo, A. Liedl, V.L. Lollo, L. Pellegrino, R. Pompili, S. Romeo, V. Shpakov, C. Vaccarezza, F. Villa LNF-INFN, Frascati, Italy M. Carillo, E. Chiadroni Sapienza University of Rome, Rome, Italy A. Cianchi, M. Galletti Università di Roma II Tor Vergata, Roma, Italy
	A new RF photo-injector has been designed, realized and successfully installed at the SPARC_LAB facility (INFN-LNF, Frascati, Rome). It is based on a 1.6 cell RF gun fabricated with the new brazing free technology recently developed at the National Laboratories of Frascati. The electromagnetic design has been optimized to have a full compensation of the dipole and quadrupole field components introduced by the coupling hole with an improvement of the effective pumping speed with two added pumping ports. The gun is overcoupled (\beta=2) to reduce the filling time and to allow the operation with short RF pulses. The overall injector integrates a new solenoid with a remote control of the transverse position and a variable skew quadrupole for the compensation of residual quadrupole field components. It also allows an on axis laser injection system with the last mirror in air, and the possibility of a future integration of an X/C band cavity linearizer. In the paper we report the main characteristics of the electromagnetic and mechanical design and the low and high power test results that shows the extremely good perfomances of the new device.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS019
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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MOPOMS020	Dark Current Studies for a High Gradient SW C-Band RF Gun	cathode, simulation, solenoid, electron	675
	F. Cardelli, D. Alesini, L. Faillace, A. Giribono, A. Vannozzi INFN/LNF, Frascati, Italy G. Di Raddo LNF-INFN, Frascati, Italy T.G. Lucas PSI, Villigen PSI, Switzerland
	It is now well-established that for the generation of very high brightness beams, required for fourth generation light sources, it is highly advantageous to use injectors based on Radiofrequency photo-guns with very high peak electric fields on the cathode (>120 MV/m). This very high surface electric field leads to the generation of undesirable electrons due to the field emission effect. The emitted electrons can be captured and propagate along the Linac forming a dark current beam, leading to background radiation that can damage the instrumentation and radioactivate components. Consequently, it is important that the emission of these electrons, and their subsequent transportation, is carefully evaluated. Recently, in the framework of the I-FAST project, a high gradient, standing wave, C-band (5712 MHz) RF photogun has been designed and will be realized soon. In this paper, the results of dark current studies and simulations are illustrated. The transport efficiency and the spectrum of the dark current have been evaluated by Particle-In-Cell simulations for different cathode peak field values considering also the effect of the focusing solenoid on the dark current beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS020
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022
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MOPOMS021	The New C Band Gun for the Next Generation RF Photo-Injectors	cathode, brightness, operation, quadrupole	679
	D. Alesini, M. Ferrario, A. Giribono, A. Gizzi, L. Piersanti, A. Vannozzi INFN/LNF, Frascati, Italy F. Cardelli, G. Di Raddo, L. Faillace, S. Lauciani, A. Liedl, L. Pellegrino, C. Vaccarezza LNF-INFN, Frascati, Italy G. Castorina AVO-ADAM, Meyrin, Switzerland M. Croia ENEA Casaccia, Roma, Italy L. Ficcadenti INFN-Roma, Roma, Italy G. Pedrocchi SBAI, Roma, Italy
	Funding: European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730 and INFN Commission V. RF photo-injectors are widely used in modern facilities, especially in FEL, as very low-emittance and high-brightness electron sources. Presently, the RF technology mostly used for RF guns is the S band (3 GHz) with typical cathode peak fields of 80-120 MV/m and repetition rates lower than 120 Hz. There are solid reasons to believe that the frequency step-up from S band to C band (6 GHz) can provide a strong improvement of the beam quality due to the potential higher achievable cathode field (>160 MV/m) and higher repetition rate (that can reach the kHz level). In the contest of the European I.FAST project, a new C band gun has been designed and will be realized and tested. It is a 2.5 cell standing wave cavity with a four port mode launcher, designed to operate with short RF pulses (<300 ns) and cathode peak field larger than 160 MV/m. In the paper we present the electromagnetic and thermo-mechanical design and the results of the prototyping activity and rf measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS021
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
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MOPOMS022	Studies of a Ka-Band High Power Klystron Amplifier at INFN-LNF	klystron, cavity, electron, focusing	683
	M. Behtouei, L. Faillace, A. Mostacci, B. Spataro LNF-INFN, Frascati, Italy F. Bosco, M. Carillo, M. Migliorati, A. Mostacci, L. Palumbo Sapienza University of Rome, Rome, Italy F. Di Paolo, S. Fantauzzi, A. Leggieri, F. Marrese, L. Valletti Università degli Studi di Roma "Tor Vergata", Roma, Italy G. Torrisi INFN/LNS, Catania, Italy
	In the framework of the Compact Light XLS project, a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM₀₁₀ mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6 MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high- power microwave window for a Ka-band klystron providing 16MW of peak power.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS022
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 10 July 2022
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MOPOMS028	Stability and Lifetime Studies of Carbon Nanotubes for Electron Cooling in ELENA	electron, cathode, proton, antiproton	699
	B. Galante, G. Tranquille CERN, Meyrin, Switzerland J. Resta-López, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom J. Resta-López, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom J. Resta-López ICMUV, Paterna, Spain
	Funding: Work supported by EU Horizon 2020 research and innovation programme under the Marie Sk’odowska-Curie grant agreement No 721559. Electron cooling is a fundamental process to guarantee beam quality in low energy antimatter facilities. In ELENA, the electron cooler reduces the emittance blow-up of the antiproton beam so that a focused and bright beam can be delivered to the experiments at the unprecedentedly low energy of 100 keV. To achieve a cold beam at this low energy, the electron gun must emit a monoenergetic and relatively intense electron beam. An optimization of the electron gun involving a cold cathode is studied to investigate the feasibility of using carbon nanotubes (CNTs) as cold electron field emitters. CNTs are considered among the most promising field emitting materials. However, stability data for emission over hundreds of hours, as well as lifetime and conditioning process studies to ensure optimal performance, are still incomplete or missing, especially if the aim is to use them in operation. This contribution reports experiments that characterize these properties and assess whether CNTs are suitable to be used as cold electron field emitters for many hundreds of hours.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS028
About •	Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022
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MOPOMS052	6 MeV Novel Hybrid (Standing Wave - Traveling Wave) Photo-Cathode Electron Gun for a THz Superradiant FEL	electron, cathode, klystron, experiment	760
	A. Nause, L. Feigin, A. Friedman, A. Weinberg Ariel University, Ariel, Israel A. Fukasawa, J.B. Rosenzweig UCLA, Los Angeles, California, USA B. Spataro LNF-INFN, Frascati, Italy
	A novel 6 MeV hybrid photo injector was designed and commissioned at Ariel University in Israel as an on-going collaboration with UCLA. This unique, new generation design provides a radically simpler approach to RF feeding of a gun/buncher system, leading to a much shorter beam via velocity bunching owed to an attached traveling wave section of the photo-injector. This design results in better performance in beam parameters, providing a high quality electron beam, with energy of 6 MeV, emittance of less than 3 ’m, and a 150 fs pulse duration at up to 1 nC per pulse. The Hybrid gun is driven by a SLAC XK5 Klystron as the high power RF source, and third harmonic of a fs level IR Laser amplifier (266 nm) to extract electrons from the Cathode. The unique e-gun will produce a bunched electron pulse to drive a THz FEL, which will operate at the super-radiance regime, and therefore requires extraordinary beam properties. It will also be used for MeV UED experiments in a separate line using a dogleg section. Here we describe the gun and presents experimental results from the gun and its sub-systems, including energy and charge measurements, compared with the design simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS052
About •	Received ※ 11 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022
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TUOZSP3	The European ERL Roadmap	electron, FEL, linac, SRF	831
	A. Hutton JLab, Newport News, Virginia, USA M. Klein The University of Liverpool, Liverpool, United Kingdom B.C. Kuske HZB, Berlin, Germany
	Funding: AH supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177 Following the European Strategy process in 2019, five Roadmap Panels were set up to prepare the technologies needed for future accelerators and colliders: high-field magnets, SRF, muon colliders, plasma wakefield accelerators and Energy Recovery Linacs (ERLs). The ERL Roadmap Panel, consisting of ERL experts from around the world, first developed an overview of current and future ERLs. From this it was possible to carry out a gap analysis to see what R&D would be needed, from which the Roadmap could be developed. The European ERL Roadmap focused on three main aspects: 1) the continuation and development of facility programs for which no additional funds are needed, S-DALINAC in Darmstadt and MESA in Mainz; 2) technology development for room-temperature HOM damping and twin-axis SRF cavities; 3) the timely upgrade of bERLinPro for 100 mA current and the construction of PERLE at Orsay as a dedicated 10 MW power multi-turn facility. The roadmap entails a vision of future energy frontier electron-positron and electron-hadron collider and describes a high quality ERL program for 4.4 K SRF technology at high Q₀. The presentation will address the ERL Roadmap process and result in detail.
	Slides TUOZSP3 [2.868 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOZSP3
About •	Received ※ 02 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 29 June 2022
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TUPOST056	Multi-Objective Bayesian Optimization at SLAC MeV-UED	electron, controls, detector, timing	995
	F. Ji, A.L. Edelen, R.J. England, P.L. Kramer, D. Luo, C.E. Mayes, M.P. Minitti, S.A. Miskovich, M. Mo, A.H. Reid, R.J. Roussel, X. Shen, X.J. Wang, S.P. Weathersby SLAC, Menlo Park, California, USA
	SLAC MeV-UED, part of the LCLS user facility, is a powerful ’electron camera’ for the study of ultrafast molecular structural dynamics and the coupling of electronic and atomic motions in a variety of material and chemical systems. The growing demand of scientific applications calls for rapid switching between different beamline configurations for delivering electron beams meeting specific user run requirements, necessitating fast online tuning strategies to reduce set up time. Here, we utilize multi-objective Bayesian optimization(MOBO) for fast searching the parameter space efficiently in a serialized manner, and mapping out the Pareto Front which gives the trade-offs between key beam parameters, i.e., spot size, q-resolution, pulse length, pulse charge, etc. Algorithm, model deployment and first test results will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST056
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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TUPOPT025	Concept of Electron Beam Diagnostics for PolFEL	radiation, FEL, electron, diagnostics	1055
	A.I. Wawrzyniak, G.W. Kowalski, A.M. Marendziak, R. Panaś NSRC SOLARIS, Kraków, Poland A. Curcio CLPU, Villamayor, Spain P.J. Czuma, M. Krakówiak, P. Krawczyk, R. Kwiatkowski, S. Mianowski, R. Nietubyc, M. Staszczak, J. Szewiński, M. Terka, M. Wójtowicz NCBJ, Świerk/Otwock, Poland K. Łasocha Jagiellonian University, Kraków, Poland
	PolFEL - Polish Free Electron Laser will be driven by a continuous wave superconducting accelerator consist-ing of low emittance superconducting RF electron gun, four accelerating cryomodules, bunch compressors, beam optics components and diagnostic elements. The acceler-ator will split in three branches leading to undulators pro-ducing VUV, IR and THz radiation, respectively. Two accelerating cryomodules will be installed before a dogleg directing electron bunches towards IR and THz branches. Additional two cryomodules will be placed in the VUV branch accelerating electron bunches up to 185 MeV at 50 kHz repetition rate. Moreover, the electron beam after passing the VUV undulator will be directed to the Inverse Compton Scattering process for high energy photons experiments in a dedicated station. In order to measure and optimise the electron beam parameters along the entire accelerator the main diagnostics components like BPMs, charge monitors, YAG screens, coherent diffrac-tion radiation (CDR) monitors and beam loss monitors are foreseen. Within this presentation the concept of the electron beam diagnostics will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT025
About •	Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022
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TUPOPT035	Introduction of Westwood Linear Accelerator Test Facility in University of California Los Angeles	laser, electron, FEL, klystron	1085
	Y. Sakai, G. Andonian, O. Camacho, A. Fukasawa, G.E. Lawler, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, O. Williams UCLA, Los Angeles, California, USA
	Funding: U.S. DOE: DE-SC0009914 U.S. DOD: DARPA GRIT Contract 20204571 U.S. DOE: DE-SC0020409 - Cryo RF An electron linear accelerator test facility located on UCLA’s southwest campus in Westwood, SAMURAI, is presently being constructed. A RF-based accelerator consists of a compact, 3 MeV S-band hybrid gun capable of velocity bunching to bunch lengths in the 100s fs range with 100s pC of charge. This beam is accelerated by an 1.5 m S-band linac with a peak output energy of 30 MeV which can be directed to either a secondary beamline or remain on the main beamline for final acceleration by a SLAC 3 m S-band linac to an energy of 80 MeV. Further acceleration by advanced boosters such as a cryo-cooled C-band structure or numerous optical or wakefield methods is under active investigation. In combination with a 3 TW Ti:Sapphire laser, initial proof of principle experiments will be conducted on topics including the ultra-compact x-ray free-electron laser, advanced dielectric wakefield acceleration, bi-harmonic nonlinear inverse Compton scattering, and various radiation detectors. Furthermore, development of a tertiary beamline based on an ultra low emittance, cryo-cooled gun will eventually enable two-beam experiments, expanding the facility’s unique experimental capabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT035
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 24 June 2022
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TUPOPT066	KEK LUCX Facility Laser-to-RF&RF-to-RF Stability Study and Optimization	laser, feedback, LLRF, timing	1167
	K. Popov Sokendai, Ibaraki, Japan A. Aryshev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	KEK LUCX facility* is a linear accelerator devoted to the beam instrumentation R&Ds for present and future accelerator systems and colliders including ILC. According to the ILC TDR, it is necessary to achieve RF-gun Laser-to-RF&RF-to-RF phase stability of 0.35°(RMS) and amplitude stability of 0.07%(RMS) with implementation of the Digital LLRF feedback based on commercially available FPGA board and digital trigger system. As the first step to achieve ILC stability level at KEK-LUCX facility, present Laser-to-RF&RF-to-RF phase and amplitude jitters were measured using time- and frequency-domain techniques. After that, jitter influence on beam parameters after RF-gun and main solenoid magnet was simulated with ASTRA tracking code* and results were cross-checked during LUCX facility beam operation. Finally, stable digital trigger system and digital LLRF feedback based on SINAP EVG&EVR and RedPitaya SIGNALlab-250 modules were implemented. This report demonstrates the results of Laser-to-RF&RF-to-RF phase and amplitude jitter measurements cross-checked with ASTRA simulation and real beam parameters measurements before and after LUCX facility stabilization. References A. Aryshev et al., Appl. Phys. Lett. 111, 033508 (2017). International Linear Collider Reference Design Report, ILC-REPORT-2007-001, 2007. **https://www.desy.de/~mpyflo/
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT066
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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TUPOPT070	Surrogate Modelling of the FLUTE Low-Energy Section	simulation, network, electron, controls	1182
	C. Xu, E. Bründermann, A.-S. Müller, A. Santamaria Garcia, J. Schäfer KIT, Karlsruhe, Germany
	Funding: Supported by the Helmholtz Association (Autonomous Accelerator, ZT-I-PF-5-6) and the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology". Numerical beam dynamics simulations are essential tools in the study and design of particle accelerators, but they can be prohibitively slow for online prediction during operation or for systematic evaluations of new parameter settings. Machine learning-based surrogate models of the accelerator provide much faster predictions of the beam properties and can serve as a virtual diagnostic or to augment data for reinforcement learning training. In this paper, we present the first results on training a surrogate model for the low-energy section at the Ferninfrarot Linac- und Test-Experiment (FLUTE).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT070
About •	Received ※ 30 May 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
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TUPOTK053	Design Progress of High Efficiency Klystron for CEPC LINAC	klystron, simulation, cavity, linac	1339
	Z.D. Zhang, Y.L. Chi, D. Dong, M. Iqbal, G. Pei, S.C. Wang, O. Xiao, S. Zhang, Z.S. Zhou IHEP, Beijing, People’s Republic of China S. Zhang, Z.D. Zhang UCAS, Beijing, People’s Republic of China
	The injector linear accelerator (LINAC) for the CEPC requires a higher efficiency klystron with 80MW output power than S band 65MW pulsed klys-tron currently operating in LINAC of BEPCII to reduce energy consumption and cost. The efficiency is ex-pected to improve from the currently observed 42% to more than 55% and output power will be improved from 65MW to more than 80MW with same operation voltage. In this paper, BAC bunching method is ap-plied for klystron efficiency improvement. The optimi-zation of the gun and solenoid parameters is complet-ed with 2-D code DGUN and then 3-D code CST. The preliminary design of the cavity parameters is also completed in 1-D disk model based AJDISK code and then further checked by 2-D code EMSYS. Finally, new klystron prototype will be fabricated in Chinese com-pany after design parameters are determined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK053
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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WEOYSP2	First Electron Beam of the ThomX Project	linac, HOM, electron, emittance	1632
	C. Bruni, M. Alkadi, J-N. Cayla, I. Chaikovska, S. Chancé, V. Chaumat, O. Dalifard, N. Delerue, K. Dupraz, M. El Khaldi, N. ElKamchi, E.E. Ergenlik, P. Gauron, A. Gonnin, E. Goutierre, H. Guler, M. Jacquet, V. Kubytskyi, P. Lepercq, F. Letellier-Cohen, J.C. Marrucho, B. Mercier, E. Mistretta, H. Monard, A. Moutardier, M. Omeich, V. Soskov, F. Wicek Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	Funding: The present work is financed by the French National Research Agency (ANR) under the Equipex program ANR-10-EQPX-0051. The ThomX accelerator beam commissioning phase is now ongoing. The 50 MeV electron accelerator complex consists of a 50 MeV linear accelerator and a pulsed mode ring. It is dedicated to the production of X-rays by Compton backscattering. The performance of the beam at the interaction point is demanding in terms of emittance, charge, energy spread and transverse size. The choice of an undamped ring in pulsed mode also stresses the performance of the beam from the linear accelerator. Thus, commissioning includes a beam based alignment and a simulation/experimental matching procedure to reach the X-ray beam requirements. We will present the first 50 MeV electron beam obtained with ThomX and its characteristics. on behalf of the ThomX collaboration : ThomX collaboration, https://thomx.ijclab.in2p3. fr/collaboration-thomx/, [Online; accessed 19-May- 2022].
	Slides WEOYSP2 [80.558 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP2
About •	Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 06 July 2022
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WEPOPT025	Flat Beam Generation with the Phase Space Rotation Technique at KEK-STF	emittance, collider, experiment, cathode	1897
	M. Kuriki, Z.J. Liptak HU/AdSM, Higashi-Hiroshima, Japan S. Aramoto Hiroshima University, Higashi-Hiroshima, Japan H. Hayano, X.J. Jin, Y. Seimiya, N. Yamamoto, Y. Yamamoto KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan K. Sakaue The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan M. Washio RISE, Tokyo, Japan
	Flat beam generation from angular momentum dominated beam with a phase-space rotation technique is an unique method to manipulate the phase-space distribution of beam. As an application, the asymmetric emittance beam generation for linear colliders is considered to compensate the Beamstrahlung effect at Interaction point. By using this technique, the asymmetric beam can be generated directly with the injector, instead of radiation damping with a huge damping ring. We present the result of a proof-of-principle experiment at KEK-STF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT025
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
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WEPOPT065	Simulations of the Upgraded Drive-Beam Photoinjector at the Argonne Wakefield Accelerator	solenoid, emittance, laser, electron	2015
	E.A. Frame, P. Piot Northern Illinois University, DeKalb, Illinois, USA S.Y. Kim, X. Lu, J.G. Power, D.S. Scott, E.E. Wisniewski ANL, Lemont, Illinois, USA
	Funding: Department of Energy The Argonne Wakefield Accelerator (AWA) is planning to upgrade its photoinjector for the drive-beam accelerator. The main goal of the upgrade is to improve the beam brightness using a symmetrized RF-gun cavity. In the process, the photoinjector was reconfigured and some of the solenoid magnets redesigned. A challenging aspect of this optimization is that the injector should be able to produce bright low-charge (~1 nC) bunches while also being capable of operating at high-charge (~50 nC) bunches. This paper will discuss the optimization of the beam dynamics for the low- and high-charge cases and explore the performances of the proposed configuration using a model of the full AWA drive-beam beamline including 3D field maps for the external electromagnetic fields. The optimizations are performed with ASTRA and the DEAP toolbox and with OPAL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT065
About •	Received ※ 08 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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WEPOTK003	Status of the Development of the Electron Lens for Space Charge Compensation at GSI	electron, cathode, solenoid, space-charge	2027
	K. Schulte-Urlichs, D. Ondreka, P.J. Spiller, K.I. Thoma GSI, Darmstadt, Germany M. Droba, T. Dönges, O. Meusel, H. Podlech IAP, Frankfurt am Main, Germany
	At GSI a prototype electron lens for space charge (SC) compensation is currently being designed and main components as the RF-modulated electron gun are already under commissioning. The goal of this project is the (partial) compensation of SC forces within the ion beam by an overlapping electron beam. This may help to increase the intensity of primary beams, especially in the FAIR facility and potentially all large synchrotrons operated at the SC limit. For an effective SC compensation, the generated electron beam needs to follow the transverse and longitudinal beam profile of the ion bunch structure. The requirements are maximum currents of 10 A and grid modulation to cover a broad frequency range from 400 kHz to 1 MHz. The RF-modulated electron gun was designed and manufactured in the scope of the ARIES collaboration and is currently being tested at the E-Lens Lab of Goethe University Frankfurt. A dedicated test bench was built for commissioning of the major e-lens components and diagnostics. In this contribution the overall set-up will be presented putting special emphasis on the beam dynamics and collector design as well as as well as simulation results of the electron gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK003
About •	Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022
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WEPOTK060	Prospects of Ultrafast Electron Diffraction Experiments at Sealab	electron, experiment, SRF, cavity	2201
	B. Alberdi-Esuain, J.-G. Hwang, T. Kamps, A. Neumann, J. Völker HZB, Berlin, Germany T. Kamps HU Berlin, Berlin, Germany
	Ultrafast Electron Diffraction (UED) is a pump-probe experimental technique that aims to image the structural changes that happen in a target structure due to photo-excitation. Development of MeV UED capabilities is one of the main objectives at Sealab, a superconducting RF accelerator facility being commissioned in Helmholtz-Zentrum Berlin. In order to perform UED experiments, the optimization of temporal resolution is of the utmost importance. The composition of the SRF Photoinjector, currently the main beam-line in Sealab, offers superb flexibility to manipulate the longitudinal phase-space of the electron bunch. At the same time, the CW operation of the accelerator provides an enhanced beam stability compared to warm guns, together with MHz repetition rates. This work aims to show the capacity of the SRF Photoinjector in Sealab to reach the required temporal resolution and explain the development and current status of the necessary tools to perform UED experiments at the facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK060
About •	Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022
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WEPOMS024	Present Status of the Injector at the Compact ERL at KEK	FEL, emittance, linac, operation	2296
	O.A. Tanaka, T. Miyajima, T. Tanikawa KEK, Ibaraki, Japan
	The Compact ERL at KEK is a test accelerator to develop ERL technologies and their possible applications. The first target of injector operation to demonstrate IR-FEL was to generate high bunch charge electron beams with low longitudinal emittance and short bunch length. In 2020, the injector was operated with the bunch charge of 60 pC, the DC gun voltage of 480 kV, the injector energy of 5 MeV and the bunch length of 2 ps rms, and the required beam quality for the IR-FEL has been achieved for a single-pass operation mode. The next target is to demonstrate IR-FEL generation for recirculation mode. The injector energy is decreased to 3.5 MeV due to a limitation of the energy ratio between injection and recirculation beams. Moreover, the DC gun voltage decreases to 390 kV due to the troubles of the DC gun. Therefore, control of the space charge effect is more important to design and optimize the beam transport condition of the injector. In this report, a strategy of the injector optimization together with its realization results and future prospects are summarized.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS024
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 21 June 2022
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WEPOMS055	Cathode Space Charge in Bmad	space-charge, cathode, simulation, controls	2380
	N. Wang Cornell University, Ithaca, New York, USA J.A. Crittenden, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes SLAC, Menlo Park, California, USA
	Funding: This project was supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. We present an implementation of charged particle tracking with the cathode space charge effect included which is now openly available in the Bmad toolkit for charged particle simulations. Adaptive step size control is incorporated to improve the computational efficiency. We demonstrate its capability with a simulation of a DC gun and compare it with the well-established space charge code Impact-T.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS055
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 05 July 2022
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THPOST006	Simulations of the Suitability of a DC Electron Photogun and S-Band Accelerating Structure as Input to an X-Band Linac	simulation, emittance, electron, acceleration	2445
	S.D. Williams, R.P. Rassool, S.L. Sheehy, G. Taylor, M. Volpi The University of Melbourne, Melbourne, Victoria, Australia R. Auchettl, R.T. Dowd AS - ANSTO, Clayton, Australia
	Work has been underway for some time to design a compact electron beamline utilising X-band linear accelerating structures in the new Melbourne X-band Laboratory for Accelerators and Beams (X-LAB). The original design utilised an S-band RF photogun as an input to a pair of high gradient X-band linear accelerating structures, but we have been motivated to investigate an alternative starting section to allow for initial testing. This will utilise a DC photogun and S-band accelerating structure similar to those used at the Australian Synchrotron. Simulation results incorporating space charge of a beamline composed of a DC photogun, S-band accelerating structures, and two high gradient X-band structures will be presented. These simulation results will be optimised for minimum emittance at the end of the beamline.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST006
About •	Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 22 June 2022
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THPOST007	Slow-Control Loop to Stabilize the RF Power of the FLUTE Electron Gun	controls, cavity, electron, LLRF	2449
	M.-D. Noll, A. Böhm, J. Jelonek, I. Križnar, O. Manzhura, A.-S. Müller, R. Ruprecht, M. Schuh, N.J. Smale KIT, Karlsruhe, Germany
	The linear accelerator FLUTE (Far Infrared Linac and Test Experiment) at KIT serves as a test facility for accelerator research and for the generation of ultra-intense coherent THz radiation. To achieve stable THz photon energy and optimal beam trajectory, the energy of the electrons emitted from the RF photo-injector must be stable. The accelerating voltage of the RF cavity has been shown to be a significant influencing factor. Here, we report on the development of a slow closed-loop feedback system to stabilize the RF power and thus the accelerating voltage in the RF photo-injector cavity. With this closed-loop feedback system the relative standard deviation of the RF power in the cavity can be improved by 8.5 %.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST007
About •	Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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THPOST017	Physical Design of a 10 MeV High Scanning Frequency Irradiation Electron Linear Accelerator	electron, radiation, simulation, kicker	2476
	S. Zhang, Z.D. Zhang UCAS, Beijing, People’s Republic of China Y.L. Chi, M. Iqbal, J.R. Zhang, S. Zhang, Z.D. Zhang, Z.S. Zhou IHEP, Beijing, People’s Republic of China
	A compact 10 MeV irradiation S-band electron linear accelerator has been proposed to carry out the electron radiation effect test of materials and devices. The Linac includes a standing wave pre-buncher, a traveling wave bunching accelerating structure. The traveling wave accelerating structure uses a 5MW klystron as RF source and provides electron beam energy 3.5-10MeV and average current 0.01-1mA. The required irradiation scanning frequency is very high, up to 100Hz and irradiation area is large (200mm×200mm). To meet the requirements, a novel beam scanning system, including one kicker for horizontal scanning and one magnet for vertical scanning, have been proposed. This paper presents the physical design of the 10MeV electron Linac and beam dynamics simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST017
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 14 June 2022
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THPOST019	Generation of Transversely Uniform Bunches from a Gaussian Laser Spot in a Photoinjector for Irradiation Experiments	space-charge, laser, linac, electron	2483
	L.A. Dyks, P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom P. Burrows JAI, Oxford, United Kingdom R. Corsini, A. Latina CERN, Meyrin, Switzerland
	Beams of uniform transverse beam profile are desirable for a variety of applications such as irradiation experiments. The generation of beams with such profiles has previously been investigated as a method of reducing emittance growth. These methods, however, often use complicated optics setups or short, femtosecond laser pulse lengths. In this paper, we demonstrate that if ultra low emittance is not the target of the photoinjector, it is possible to produce transversely uniform beam profiles using a simple Gaussian laser, with a bunch length of a few picoseconds, utilising space-charge effects only.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST019
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THPOST021	Beam Dynamics Simulations of Linear Accelerator for Natural Rubber Vulcanization at Chiang Mai University	electron, simulation, linac, cathode	2491
	J. Saisut, S. Rimjaem, C. Thongbai Chiang Mai University, Chiang Mai, Thailand M. Jitvisate Suranaree University of Technology, Nakhon Ratchasima, Thailand S. Rimjaem, J. Saisut, C. Thongbai ThEP Center, Commission on Higher Education, Bangkok, Thailand
	The Linear accelerator system for natural rubber vulcanization has been developed at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The main components of the accelerator system consist of a DC electron gun with a thermionic cathode, an RF linear accelerator, an RF system, a control system, and an irradiation system. The electron beam properties for natural rubber vulcanization are predicted from the beam dynamics simulation starting from a cathode to the titanium exit window. The electron beam generation and the particle in cell simulation inside the DC electron gun are performed using CST Studio Suit software. The electron distribution at the gun exit from the CST output is covered to be an input distribution of the ASTRA beam dynamics simulation program. The electron beam enters linac and is accelerated by RF filed inside the linac. The ASTRA simulation code is used to track electron trajectories including the space-charge interaction and the simulation starts from linac entrance to the exit windows. The electron beam properties for various conditions are evaluated and will be used for further simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST021
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 03 July 2022
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THPOST040	Commissioning of an X-Band Cavity for Longitudinal Phase Space Linearization at UCLA PEGASUS Laboratory	cavity, electron, linac, emittance	2533
	P.E. Denham, P. Musumeci, A. Ody UCLA, Los Angeles, USA
	This paper discusses the commissioning of an X-band (9.6 Ghz) linearizer cavity at the UCLA PEGASUS beamline. The photoinjector gun and booster linac operate at S-band (2.856 GHz) and the linearizer cavity can be used to compensate temporally correlated energy spread inherited by the use of relatively long (many ps) laser pulses at the photocathode. The cavity is comprised of 7 cells for a total length of a 9.45 cm, and is installed in the drift section between the gun and the linac. It can be used to remove higher order correlations and minimize the beam energy spread of 13 ps long beams to 10^-4.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST040
About •	Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 27 June 2022
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THPOST046	CrYogenic Brightness-Optimized Radiofrequency Gun (CYBORG)	cryogenics, cathode, cavity, brightness	2544
	G.E. Lawler, A. Fukasawa, N. Majernik, J.R. Parsons, J.B. Rosenzweig, Y. Sakai, A. Suraj UCLA, Los Angeles, California, USA
	Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132 and DOE Contract DE-SC0020409 Producing higher brightness beams at the cathode is one of the main focuses for future electron beam applications. For photocathodes operating close to their emission threshold, the cathode lattice temperature begins to dominate the minimum achievable intrinsic emittance. At UCLA, we are designing a radiofrequency (RF) test bed for measuring the temperature dependence of the mean transverse energy (MTE) and quantum efficiency for a number of candidate cathode materials. We intend to quantify the attainable brightness improvements at the cathode from cryogenic operation and establish a proof-of-principle cryogenic RF gun for future studies of a 1.6-cell cryogenic photoinjector for the UCLA ultra compact XFEL concept (UC-XFEL). The test bed will use a C-band 0.5-cell RF gun designed to operate down to 45 K, producing an on-axis accelerating field of 120 MV/m. The cryogenic system uses conduction cooling and a load-lock system is being designed for transport and storage of air-sensitive high brightness cathodes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST046
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022
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THPOPT005	Field Enhanced, Compact S-Band Gun Employing a Pin Cathode	electron, cathode, cavity, multipactoring	2567
	R. Bazrafshan, T. Rohwer Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany M. Fakhari, K. Flöttmann, F.X. Kaernter DESY, Hamburg, Germany N.H. Matlis CFEL, Hamburg, Germany
	S-band RF-guns are highly developed for production of low emittance relativistic electron bunches, but need powerful klystrons for driving. Here, we present the design and first experimental tests of a compact S-band gun, which can accelerate electrons up to 180 keV powered by only 10 kW from a compact rack-mountable solid-state amplifier. A pin-cathode is used to enhance the RF electric field on the cathode up to 100 MV/m as in large-scale S-band guns. An electron bunch is generated through photoemission off a flat copper surface on the pin excited by a UV laser pulse followed by a focusing solenoid producing a low emittance bunch with 0.1 mm mrad transverse emittance for up to 100 fC bunch charge. We are currently in the conditioning phase of the gun and first experiments show good agreement with simulations. The compact gun will serve three purposes: (i) it can be used directly for ultrafast electron diffraction; (ii) as an injector into a THz booster producing 0.3MeV to 2 MeV electron bunches for ultrafast electron diffraction; (iii) The system in (ii) serves as an injector into a THz linear accelerator producing a 20 MeV beam for the AXSIS X-ray source project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT005
About •	Received ※ 21 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
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THPOPT019	Multi-Alkali Antimonide Photocathode Development for High Brightness Beams	cathode, SRF, brightness, electron	2610
	S. Mistry, T. Kamps, J. Kühn, C. Wang HZB, Berlin, Germany T. Kamps HU Berlin, Berlin, Germany C. Wang University Siegen, Siegen, Germany
	Funding: This work is funded by the DFG CO 1509/10-1 \| MI 2917/1-1 Photocathode R&D at the Helmholtz-Zentrum Berlin (HZB) is driven by the motivation to produce high brightness electron beams for the SRF photoinjector test facility, Sealab/ bERLinPro. Multi-alkali antimonides are the choice photocathode material due to high quantum efficiency (QE) and low intrinsic emittance in the visible range. In this work a more robust alternative to the tried and tested Cs-K-Sb is considered. Na-K-Sb offers similar advantages to Cs-K-Sb including, high QE at green wavelengths but moreover, it offers excellent stability at elevated temperatures. This property could lengthen the cathode lifetime by enhancing the robustness of the photocathode inside the SRF gun. In this work, a status report showcasing first results towards the development of a growth procedure for Na-K-Sb is presented by means of spectral response and XPS measurements conducted in the HZB photocathode lab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT019
About •	Received ※ 03 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 04 July 2022
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THPOPT020	Status and Plans for the New CLS Electron Source Lab	electron, operation, linac, radiation	2614
	M.J. Boland, D. Bertwistle, F. Le Pimpec CLS, Saskatoon, Saskatchewan, Canada X.F.D. Stragier TUE, Eindhoven, The Netherlands
	The Canadian Light Source (CLS) has recently created a new Electron Source Lab (ESL) that can run independently from user operations. A section of the old Saskatchewan Accelerator Laboratory experimental nuclear physics tunnels has been rebuilt with new shielding and a separate entrance. The laboratory will be used to prepare an operational spare electron gun for the 250 MeV linac. In addition, there are plans to develop RF guns for a future branch line to inject into the linac and for possible short pulse production. This paper will give an overview of the ESL space and the first electron guns which plan to be installed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT020
About •	Received ※ 16 June 2022 — Revised ※ 29 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 08 July 2022
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THPOPT022	Study on QE Evolution of Cs₂Te Photocathodes in ELBE SRF Gun-II	cathode, SRF, operation, vacuum	2617
	R. Xiang, A. Arnold, S. Ma, P. Michel, P. Murcek, A.A. Ryzhov, J. Schaber, J. Teichert, P.Z. Zwartek HZDR, Dresden, Germany
	The quality of the photocathodes is critical for the sta-bility and reliability of the photoinjector’s operation. Thanks to the robust magnesium and Cs₂Te photocathodes, SRF gun-II at HZDR has been proven to be a suc-cessful example in CW mode for high current user operation. In this contribution, we will present our observation of the QE evolution of Cs₂Te photocathodes during SRF gun operation. The variables including substrate surface, film thickness, Cs/Te stoichiometric, multipacting, RF loading and charge extract are considered in the analysis.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT022
About •	Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 06 July 2022
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THPOPT025	Photocathode Stress Test Bench at INFN LASA	cathode, laser, electron, operation	2627
	D. Sertore, D. Giove, L. Monaco INFN/LASA, Segrate (MI), Italy A. Bacci, F. Canella, S. Cialdi, I. Drebot, D. Giannotti, L. Serafini INFN-Milano, Milano, Italy D. Cipriani, E. Suerra Università degli Studi di Milano, Milano, Italy G. Galzerano POLIMI, Milano, Italy G. Guerini Rocco Università degli Studi di Milano & INFN, Segrate, Italy
	A UHV test bench based on a 100 kV DC gun and a 100 MHz repetition rate laser has been setup up at INFN LASA to test Cs₂Te photocathodes. This operation mode is the baseline of the BriXSinO project, currently in the design phase in our laboratory, and the qualification of the Cs₂Te photocathodes is a key issue. In this paper, we present the recent advances in the different aspects of this R&D activity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT025
About •	Received ※ 10 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 20 June 2022
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THPOPT027	R&D on High QE Photocathodes at INFN LASA	cathode, FEL, operation, electron	2633
	D. Sertore, M. Bertucci, L. Monaco INFN/LASA, Segrate (MI), Italy G. Guerini Rocco Università degli Studi di Milano & INFN, Segrate, Italy S.K. Mohanty, H.J. Qian, F. Stephan DESY Zeuthen, Zeuthen, Germany
	We present the recent activities on antimonide and telluride alkali based photocathodes at INFN LASA. The R&D on Cs₂Te materials is focused on investigating effects of material thickness and growth procedures on the photocathodes performances during operation in RF guns. We aim to improve thermal emittance and long term stability of these films. The more recent work on alkali antimonide showed the need for substantial improvements in stability and QE during operation. We present here our recent achievements and plans for future activities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT027
About •	Received ※ 09 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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THPOPT036	New Microwave Thermionic Electron Gun for APS Upgrade: Test Results and Operation Experience	linac, cathode, operation, injection	2665
	S.V. Kutsaev, R.B. Agustsson, A.C. Araujo Martinez, R.D. Berry, O. Chimalpopoca, A.Y. Murokh, M. Ruelas, A.Yu. Smirnov, S.U. Thielk RadiaBeam, Santa Monica, California, USA J.E. Hoyt, W.G. Jansma, A. Nassiri, Y. Sun, G.J. Waldschmidt ANL, Lemont, Illinois, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Basic Energy Science, under contracts DE-SC0015191 and DE- AC02-06CH11357 Recently, RadiaBeam has designed and built a robust thermionic RF gun with optimized electromagnetic per-formance, improved thermal engineering, and a robust cathode mounting technique. This gun allows to improve the performance of existing and future light sources, industrial accelerators, and electron beam driven te-rahertz sources. Unlike conventional electrically or side-coupled RF guns, this new gun operates in ’-mode with the help of magnetic coupling holes. Such a design al-lows operation at longer pulses and has negligible dipole and quadrupole components. The gun prototype was built, then installed and tested at the Advanced Photon Source (APS) injector. This paper presents the results of high power and beam tests of this RF gun, and operation-al experience at APS to this moment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT036
About •	Received ※ 31 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
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THPOTK014	100 keV Electron Source Design for the New 3 GeV Synchrotron Facility in Thailand	cathode, electron, focusing, simulation	2800
	N. Juntong, S. Bootiew, T. Chanwattana, Ch. Dhammatong, S. Jummunt, K. Kittimanapun, W. Phacheerak SLRI, Nakhon Ratchasima, Thailand K. Manasatitpong Synchrotron Light Research Institute (SLRI), Muang District, Thailand
	The Synchrotron Light Research Institute (SLRI) is developing a new synchrotron light source with an electron beam energy of 3 GeV. The DC thermionic electron gun was chosen because it is simple and less cost. The design process is well known. The operation is more stable compared to the RF gun. The cathode Y-646B was considered because it had already been used at the old synchrotron machine and the possibility of sharing the stock outweighs other disadvantages. Moreover, it is used in many synchrotron facilities, so it is easy to find references. The present of the focusing electrode was discussed. The focusing electrode will increase the complexity of the gun, but it is necessary to get a high-quality beam from the gun. The designed electron gun can produce 1.1 A beams current with the normalized emittance of 0.910 Pi·mm·mrad, which satisfied the requirement of the linac injector. The design and study results will be discussed in this report.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK014
About •	Received ※ 20 May 2022 — Accepted ※ 14 June 2022 — Issue date ※ 29 June 2022
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THPOTK015	Solid-State Pulsed Power Supply for a 100 keV Electron Source of the New Synchrotron Facility in Thailand	electron, high-voltage, power-supply, simulation	2803
	W. Phacheerak, S. Bootiew, T. Chanwattana, Ch. Dhammatong, N. Juntong, K. Kittimanapun SLRI, Nakhon Ratchasima, Thailand K. Manasatitpong Synchrotron Light Research Institute (SLRI), Muang District, Thailand
	The new synchrotron light source project in Thailand will utilize a thermionic DC electron gun. The maximum operation of the gun is 100 keV, which requires a pulsed power supply of 100kV. The present synchrotron machine uses a conventional design of the gun power supply. To improve the high voltage pulsed quality, the solid-state design of the gun power supply is utilized. The output pulse width can be adjusted easily and the droop is less compared to the conventional design. The designed output of 100 kV amplitude with 5 µs pulsed width can be achieved with this design. It also produces a less droop of 1.8%. The design process and results will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK015
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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THPOTK041	Development of Programmable Bipolar Multi kHz Kicker Drivers for Long Pulse Superconducting Electron Linacs	kicker, FEL, electron, laser	2862
	J.L. Teichgräber, W. Decking, J. Kahl, F. Obier DESY, Hamburg, Germany
	Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany Superconducting cavities allow for long rf-pulses, which enable the acceleration of thousands of electron bunches within one rf-pulse. Due to transient effects, e.g. coupler kicks, eddy currents or wakefields, bunch properties like the beam trajectory can change along the pulse train. To compensate for this, kicker systems based on high-current operational amplifiers have been developed for the free electron lasers European XFEL and FLASH at DESY in Hamburg. Here, we present the layout of the kicker system, the setup of the pulse electronics, and operational results with beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK041
About •	Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 19 June 2022
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THPOTK054	Proposal of a VHEE Linac for FLASH Radiotherapy	linac, electron, cavity, simulation	2903
	L. Giuliano, F. Bosco, M. Carillo, D. De Arcangelis, A. De Gregorio, L. Ficcadenti, D. Francescone, G. Franciosini, M. Migliorati, A. Mostacci, L. Palumbo, V. Patera, A. Sarti Sapienza University of Rome, Rome, Italy D. Alesini, A. Gallo, A. Vannozzi INFN/LNF, Frascati, Italy M. Behtouei, L. Faillace, B. Spataro LNF-INFN, Frascati, Italy M.G. Bisogni, F. Di Martino, J.H. Pensavalle INFN-Pisa, Pisa, Italy G.A.P. Cirrone, G. Cuttone, G. Torrisi INFN/LNS, Catania, Italy V. Favaudon, A. Patriarca Institut Curie - Centre de Protonthérapie d’Orsay, Orsay, France S. Heinrich Institut Curie, Centre de Recherche, Orsay, France
	Translation of electron FLASH radiotherapy in clinical practice requires the use of high energy accelerators to treat deep tumours and Very High Electron Energy (VHEE) could represent a valid technique to achieve this goal. In this sce- nario, a VHEE FLASH linac is under study at the University La Sapienza of Rome (Italy) in collaboration with the Italian Institute for Nuclear Research (INFN) and the Curie Insti- tute (France). Here we present the preliminary results of a compact C-band system aiming to reach an high accelerating gradient and an high pulse current necessary to deliver high dose per pulse and ultra-high dose rate required for FLASH effect. We propose a system composed of a low energy high current injector linac followed by a modular section of high accelerating gradient structures. CST code is used to define the required LINAC’s RF parameters and beam dynamics simulations are performed using T-Step, ASTRA and GPT tracking codes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK054
About •	Received ※ 17 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022
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THPOTK059	Laser System for SuperKEKB RF Gun in Phase III Commissioning	laser, electron, MMI, injection	2914
	R. Zhang, M. Yoshida, X. Zhou KEK, Ibaraki, Japan H.K. Kumano, N. Toyotomi Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	In order to generate high quality electron beam with high charge in Phase III commissioning of SuperKEKB, some improvements have been done in Ytterbium doped fiber and Neodymium doped YAG (Nd:YAG) hybrid laser system. Spatial reshaping part for the 4th harmonic laser beam at 266 nm has been adopted to realize low emittance electron beam. In addition, for achieving continuous and stable laser operation, position feedback system has also been used to improve the pointing stability of laser beam. In 2021 commissioning of SuperKEKB, stable 2 nC electron beam is generated for high energy ring (HER) injection. Meanwhile, we achieved the best emittance results at B-sector of linac injector and BT line for comparable low injection background and higher injection efficiency. With the aim of generating higher charge electron beam with good quality in the following commissioning, a perspective towards the next step update for current laser system is also introduced.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK059
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 04 July 2022
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THPOMS013	Electron Gun System Design for FLASH Radiotherapy	electron, cathode, power-supply, radiation	2970
	H.-S. Lee, J.H. Jang, K.Y. Jang, J.C. Koo, H.S. Shin, D.H. Yu VITZRONEXTECH, Ansan-si, Gyeonggi-do, Republic of Korea D.H. An, S.H. Choi, K.U. Kang, G.B. Kim, J.H. Kim KIRAMS, Seoul, Republic of Korea Y.G. Son PAL, Pohang, Republic of Korea
	An electron gun is a device that emits electron beams used in an electron accelerator, an electron beam welder, an x-ray generator, etc. This device can be broadly divided into three components: a cathode, a grid, and an anode. A medical electron gun, which is a sub-system of an electron accelerator for FLASH radiotherapy, requires a high current. The electron gun was designed to obtain a peak current up to 15A using EIMAC Y824 cathode. We would like to introduce the structure of the electron gun and the required power supply system. In this paper, we will describe the optimization process of the electron gun structure design, the Marx-type power supply providing 200 kV pulse voltage, and the grid pulse power supply ranging from 1ns to 1.5 ’s. Electron gun design, Accelerator, Radiotherapy, High Current
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS013
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 28 June 2022 — Issue date ※ 10 July 2022
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THPOMS036	HERACLES: A High Average Current Electron Beamline for Lifetime Testing of Novel Photocathodes	cathode, electron, vacuum, laser	3041
	M.B. Andorf, J. Bae, A.C. Bartnik, I.V. Bazarov, J.M. Maxson Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA L. Cultrera BNL, Upton, New York, USA
	Funding: DOE-NP DE-SC0021425 NSF PHY 1549132 We report on the building and commissioning of a high current beamline dedicated to testing novel photocathodes for high current and spin-polarized electron applications. The main features of the beamline are a 200 keV DC electron gun and a beam dump capable of handling 75 kW of beam power. In this report, a Cs3Sb photocathode is used to demonstrate the facilities high current capabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS036
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 30 June 2022
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FRIXSP1	Low-Emittance Compact RF Electron Gun with a Gridded Thermionic Cathode	electron, emittance, cathode, cavity	3124
	T. Asaka JASRI/SPring-8, Hyogo-ken, Japan
	A new type of rf electron gun has been developed to generate a stable electron beam with a low-emittance of ~1 um.rad, that can be injected into SX-FEL and DLSR, without using a large UV laser system nor an ultra-high voltage pulsers. This electron gun consists of a 50 kV pulsed gun equipped with a commercially available thermionic cathode with grid and a 238-MHz acceleration cavity driven by a 42 kW solid-state amplifier. The system is simple, stable, robust, and of easy-maintenance. To obtain a "grid-transparent" condition, the cathode voltage and the control grid voltage are optimized not to distort the electric field near the grid. To avoid the emittance growth due to the space charge effect, the gun and a special magnetic lens are embedded in the 238-MHz cavity at the shortest distance, and the beam energy is immediately accelerated to 500 kV. The first model of this electron gun has been operated as the 1 GeV injector of the NewSUBARU storage ring. The same electron gun will also be used in the injector linac of the 3 GeV light source under construction in Japan. The talk is expected to include the concept, overall design and the achieved performance.
	Slides FRIXSP1 [2.893 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXSP1
About •	Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 23 June 2022
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FRPLYGD2	Access to Effective Cancer Care in Low- Middle Income Countries Requires Sophisticated Linear Accelerator Based Radiotherapy	linac, radiation, survey, electron	3147
	M. Dosanjh CERN, Meyrin, Switzerland
	There are substantial and growing gaps in cancer care for millions of people in Low- Middle- Income countries (LMICs) and for geographically remote settings in High-income countries (HICs), often indigenous populations. Assessing the cancer care shortfall led to understanding the essential gap, that of a radiation therapy machine that can reliably and effectively provide the appropriate first-rate cancer treatments within the challenging environments. More than 10,000 electron linear accelerators (linacs) are currently used worldwide to treat patients. However only 10% of patients in low-income and 40% in middle-income countries who need radiotherapy have access to it. The idea to address the need for a novel medical linac for challenging environments has led to the creation of the STELLA project (Smart Technology to Extend Lives with Linear Accelerators) project. STELLA is multidisciplinary international collaborative effort to design and develop an affordable and robust yet technically sophisticated linear accelerator-based radiation therapy treatment (RTT) in LMICs. Here we describe Project STELLA.
	Slides FRPLYGD2 [6.047 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRPLYGD2
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 29 June 2022
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Paper

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MOPOPT057

Updates in Efforts to Data Science Enabled MeV Ultrafast Electron Diffraction System

electron, network, laser, experiment

397

S. Biedron, T.B. Bolin, M. Martínez-Ramón, S.I. Sosa Guitron
UNM-ECE, Albuquerque, USA
M. Babzien, M.G. Fedurin, J.J. Li, M.A. Palmer
BNL, Upton, New York, USA
S. Biedron
UNM-ME, Albuquerque, New Mexico, USA
D. Martin, M.E. Papka
ANL, Lemont, Illinois, USA

Funding: Work supported by DOEs EPSCoR award DE-SC0021365, used resources of the Brookhaven National Laboratory’s Accelerator Test Facility and of the Argonne Leadership Computing Facility.
MeV ultrafast electron diffraction (MUED) is a pump-probe characterization technique to study ultrafast phenomena in materials with high temporal and spatial resolution. This complex instrument can be advanced into a turn-key, high-throughput tool with the aid of machine learning (ML) mechanisms and high-performance computing. The MUED instrument at the Accelerator Test Facility in Brookhaven National Laboratory was employed to test different ML approaches for both data analysis and control. We characterized different materials using MUED, mainly polycrystalline gold and single crystal Ta2NiS5. Diffraction patterns were acquired in single shot mode and convolutional neural network autoenconder models were evaluated for noise reduction and the reconstruction error was studied to identify anomalous diffraction patterns. Electron beam energy jitter was analyzed from single shot diffraction patterns to be used as a novel diagnostic tool. The MUED beamline was also simulated using VSim to construct a surrogate model for control of beam shape and energy. Progress towards ML-based controls leveraging off Argonne Leadership Computing Facility resources will also be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT057

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Received ※ 02 July 2022 — Accepted ※ 26 June 2022 — Issue date ※ 08 July 2022

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MOPOTK003

Absorbed Dose Characteristics for Irradiation Experiments at AREAL 5 MeV Electron Linac

electron, experiment, radiation, simulation

429

V.G. Khachatryan, Z. Amirkhanyan, H. Davtyan, A. Grigoryan, B. Grigoryan, M. Ivanyan, V.H. Petrosyan, A. Vardanyan, A.S. Yeremyan
CANDLE SRI, Yerevan, Armenia
A. Grigoryan
YSU, Yerevan, Armenia

Existing electron photogun facility at the CANDLE SRI currently can provide electron beam with the energy up to 5 MeV. The beam is being used as an irradiation source in the number of material science and life science experiments. Performed beam particle tracking simulations along with intensive application of the beam diagnostic instruments (bending magnet, YAG stations, Faraday cups) allow control of the experimental samples’ irradiation parameters, particularly exposure times for given dose as well as absorbed dose spatial distribution. Direct application of the electron beam for the irradiation experiments allows achievement of high absorbed dose. For the calculation of the irradiation parameters of the experimental samples’ particle transport simulation results should be combined with the beam current measurements by Faraday Cup (FC). Dose measurements and the comparison with numerical simulations using various initial parameters (Transverse size, divergence and energy spread) permit to pin down their actual values.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK003

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Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022

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MOPOTK022

A Design Study of Injector System for Synchrotron Light Source

linac, electron, cavity, simulation

485

C. Kim, E.-S. Kim, C.S. Park
KUS, Sejong, Republic of Korea

This work presents a design study of a 200 MeV electron linear accelerator consisting of an electron gun, bunchers, and accelerator structures. We aimed to design the linac with low emittance and low energy spread. A coasting beam from a thermionic electron gun is bunched using a series of buncher cavities: sub-harmonic buncher (SHB), a pre-buncher (PB), and a Buncher. The bunched beam is then accelerated up to 200 MeV with 4 cascaded accelerating structures. The SHB was designed with one-cell standing wave structure for improving the bunching efficiency. The two types of the 500 MHz SHB were considered: elliptical and coupled-cavity linac types. We also investigated constant-gradient and constant-impedance types of 3 GHz multi-cell traveling wave resonators for following buncher cavities and accelerating structures. Depending on the type, geometries of each traveling wave structure (TWS) cavity were determined, and then the electromagnetic fields were calculated. RF powers and phases of each cavity along this linac system were optimized using beam dynamics simulation. Furthermore, the beam distributions in the transverse direction are adjusted using solenoid magnets in the lowenergy section as well as quad triplets in the high-energy section.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK022

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 17 June 2022

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MOPOTK023

Beam Dynamics Studies on the 50 MeV Electron Linear Accelerator for Ultra-High Dose Rates

electron, acceleration, cavity, cathode

489

Y. Lee, C. Kim, E.-S. Kim, C.S. Park
KUS, Sejong, Republic of Korea
H.-S. Lee, H.S. Shin
VITZRONEXTECH, Ansan-si, Gyeonggi-do, Republic of Korea

Electron beams with ultra-high dose rates (>40 Gy/s), which enable effective radiotherapy to act on deep-seated tumors in less than a second, can be generated by linear accelerators. To successfully achieve FLASH radiotherapy, we have performed the 50 MeV linear accelerator design studies. The designed electron accelerator consists of a thermionic electron gun, sub-harmonic buncher, buncher and 2.856 GHz traveling wave structure. In this report the design layout and particle tracking simulation results of the 50 MeV electron linac with high beam current are presented in detail.
FLASH radiotherapy

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK023

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022

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MOPOTK051

Modeling a Nb₃Sn Cryounit in GPT at UITF

cavity, SRF, simulation, electron

576

S. Pokharel, G.A. Krafft
ODU, Norfolk, Virginia, USA
A.S. Hofler, G.A. Krafft
JLab, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Nb₃Sn is a prospective material for future superconducting RF (SRF) accelerator cavities. The material can achieve higher quality factors, higher temperature operation and potentially higher accelerating gradients (E_acc 96 MV/m) compared to conventional niobium. In this work, we performed modeling of the Upgraded Injector Test Facility (UITF) at Jefferson Lab utilizing newly constructed Nb₃Sn cavities. We studied the effects of the buncher cavity and varied the gun voltages from 200-500 keV. We have calibrated and optimized the SRF cavity gradients and phases for the Nb₃Sn five-cell cavities energy gains with the framework of General Particle Tracer (GPT). Our calculations show the beam goes cleanly through the unit. There is full energy gain out of the second SRF cavity but not from the first SRF cavity due to non-relativistic phase shifts.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK051

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Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 19 June 2022

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MOPOTK052

CEBAF Injector Model for K_L Beam Conditions

laser, simulation, experiment, cathode

580

S. Pokharel, G.A. Krafft
ODU, Norfolk, Virginia, USA
M.W. Bruker, J.M. Grames, A.S. Hofler, R. Kazimi, G.A. Krafft, S. Zhang
JLab, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
The Jefferson Lab KL experiment will run at the Continuous Electron Beam Accelerator Facility with a much lower bunch repetition rate (7.80 or 15.59 MHz) than nominally used (249.5 or 499 MHz). While the proposed average current of 2.5 - 5.0 muA is relatively low compared to the maximum CEBAF current of approximately 180 muA, the corresponding bunch charge is atypically high for CEBAF injector operation. In this work, we investigated the evolution and transmission of low-rep-rate, high-bunch-charge (0.32 to 0.64 pC) beams through the CEBAF injector. Using the commercial software General Particle Tracer, we have simulated and analyzed the beam characteristics for both values of bunch charge. We performed these simulations with the existing injector using a 130 kV gun voltage. We have calculated and measured the transmission as a function of the photocathode laser spot size and pulse length. We report on the findings of these simulations and optimum parameters for operating the experiment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK052

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Received ※ 07 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 26 June 2022

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MOPOMS001

Progress on Development of AXSIS: A Femtosecond THz-Driven MeV Accelerator and keV X-Ray Source

electron, acceleration, linac, laser

621

N.H. Matlis, M. Fakhari, F.X. Kärtner, T. Kroh, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang
CFEL, Hamburg, Germany
R. Bazrafshan, F.X. Kärtner, T. Rohwer
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
R. Bazrafshan, M. Vahdani
University of Hamburg, Hamburg, Germany
M. Fakhari, D. Zhang
DESY, Hamburg, Germany
F.X. Kärtner, T. Kroh
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany

Funding: This work was supported by KA908-12/1 of the Deutsche Forschungsgemeinschaft and by the ERC under the European Union’s Seventh Framework Program (FP7/2007-2013) through Synergy Grant AXSIS (609920).
We report on the design and progress in implementing a THz-driven relativistic electron accelerator and associated X-ray source, the AXSIS Facility at DESY. We have developed a full layout of the machine based on a THz gun followed by a multi-cycle dielectric loaded metal waveguide THz linear accelerator to generate 20 MeV level, 10 fs electron bunches. The required THz pulse energies are on the mJ-level for the gun and multi-10-mJ-level for the THz linac. Customized laser technologies have been developed allowing for the generation of these pulses up to 1 kHz repetition rate. The generated electron bunches are then focused into a counter propagating optical pulse ’optical undulator’ to generate X-rays in the 6-7 keV range. We will discuss the overall layout of the machine, status of its implementation and technical challenges in the different components as well as diagnostics of this new type of accelerator and X-ray source.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS001

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022

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MOPOMS003

Single-Sided Pumped Compact Terahertz Driven Booster Accelerator

electron, booster, acceleration, experiment

625

T. Kroh, R. Bazrafshan, F.X. Kärtner, N.H. Matlis
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
M. Fakhari, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang
CFEL, Hamburg, Germany
F.X. Kärtner
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
K. Kawase
JAEA, Kizugawa, Japan

Funding: European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) through the Synergy Grant ’Frontiers in Attosecond X-ray Science: Imaging and Spectroscopy’ (609920).
Scaling the RF-accelerator concept to terahertz (THz) frequencies brings several compelling advantages, including compactness, intrinsic timing between the photoemission and driving field sources, and high field gradients associated with the short THz wavelength and high breakdown threshold. Recent demonstrations of such THz powered accelerators relied on two counter-propagating single-cycle THz pulses. However, to achieve high energy gains in the acceleration process high energy THz pulses are needed which in turn require complex optical setups. Here, we present on the development of a matchbox sized multi-layered accelerator designed to boost the 50 keV output of a DC electron gun to energies of ~400 keV that only requires a single THz pulse to be powered. An integrated tunable mirror inside the structure interferes the front of the driving THz pulse with its rear part such that the field in the interaction region is optimized for efficient acceleration. This reduces the complexity of the required optical setup. Such a compact booster accelerator is very promising as electron source in ultrafast electron diffraction experiments and as booster stage prior to THz based LINACs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS003

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Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022

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MOPOMS005

Start-to-End Simulations of a THz-Driven ICS Source

electron, linac, simulation, photon

631

M. Fakhari, Y.-K. Kan
DESY, Hamburg, Germany
F.X. Kärtner
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
F.X. Kärtner
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
N.H. Matlis, M. Vahdani
CFEL, Hamburg, Germany
M. Vahdani
University of Hamburg, Hamburg, Germany

We present start-to-end simulations for a fully THz-driven table-top X-ray source. A dielectric-loaded metallic cavity operating at its Higher Order Mode accelerates 1 PC photo emitted electron bunch up to 430 keV kinetic energy. The output beam of the gun is injected into a dielectric-loaded waveguide where phase velocity of the traveling wave is adjusted in such a way that electrons see an accelerating field all the way along the tube resulting to an 18.5-MeV output beam which is then transported to an inverse Compton scattering (ICS) stage. The injection phase of the electrons can be tuned to introduce a negative energy chirp to the electron bunch leading to a ballistic bunch compression after the linac. In addition, a set of permanent magnet quadrupoles is designed to focus the beam at the ICS interaction point where the electron beam scatters off a 250-mJ, 0.5ps, 1-µm laser beam and generates an X-ray beam with 2.6x10⁷ photons per shot containing photon energies 2keV< Eph <8keV in a beam with 50 mrad half opening angle. The required terahertz waves to power the gun and linac are 550-ps pulses at 300 GHz containing 5 mJ and 23 mJ energies respectively with 1 kHz repetition rate.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS005

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Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022

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MOPOMS013

Toward Emittance Measurements at 11.7 GHz Short-Pulse High-Gradient RF Gun

linac, emittance, GUI, experiment

649

S.V. Kuzikov, C.-J. Jing, E.W. Knight
Euclid TechLabs, Solon, Ohio, USA
G. Chen, C.-J. Jing, P. Piot, E.E. Wisniewski
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid Beamlabs, Bolingbrook, USA
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot, W.H. Tan
Northern Illinois University, DeKalb, Illinois, USA

Funding: This project is supported with DoE SBIR Phase II Grant #DE-SC0018709.
A short pulse high gradient RF gun has been recently tested at Argonne Wakefield Accelerator (AWA) facility. The carried-out test showed that the 1,5-cell gun was able to inject 3 MeV, up to 100 pC bunches at room tem-perature being fed by 9 ns up to 300 MW 11.7 GHz puls-es. The cathode field was as high as about 400 MV/m. So high field is aimed to mitigate repealing Coulomb forces substantially. In accordance with simulations the emit-tance could be as low as less than 0.2 mcm. To obtain so low emittance in the experiment, the gun is assumed to be equipped with a downstream linac to be fed from the same power extractor as the gun itself. Here we report design of the RF power distribution system splitting RF power among the gun and the linac, results of low-power tests, and emittance measurement plans for upcoming new experiment at AWA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS013

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Received ※ 01 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 01 July 2022

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MOPOMS014

Commissioning of a High-Gradient X-Band RF Gun Powered by Short RF Pulses from a Wakefield Accelerator

electron, laser, cathode, MMI

652

W.H. Tan, X. Lu, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
S.P. Antipov, C.-J. Jing, E.W. Knight, S.V. Kuzikov
Euclid TechLabs, Solon, Ohio, USA
D.S. Doran, G. Ha, C.-J. Jing, W. Liu, X. Lu, P. Piot, P. Piot, J.G. Power, J. Shao, C. Whiteford, E.E. Wisniewski
ANL, Lemont, Illinois, USA

Funding: This work is supported by the U.S. DOE, under award No. DE-SC0018656 to NIU, DOE SBIR grant No DE-SC0018709 at Euclid Techlabs LLC, and contract No. DE-AC02-06CH11357 with ANL.
A high-gradient X-band (11.7-GHz) photoinjector developed by Euclid Techlabs, was recently commissioned at the Argonne Wakefield Accelerator (AWA). The system comprises a 1+1/2-cell RF gun powered by short RF pulses generated as a train of high-charge bunches from the AWA accelerator passes through a slow-wave power extraction and transfer structure. The RF photoinjector was reliably operating with electric fields in excess of 300 MV/m on the photocathode surface free of breakdown and with an insignificant dark-current level. We report on the RF-gun setup, commissioning, and the associated beam generation via photoemission.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS014

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 19 June 2022

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MOPOMS018

Tungsten Electron Emitter (TE²) with Direct Heated Cathode by Plasma Stream

cathode, electron, plasma, ion-source

667

K.I. Thoma, M. Droba, T. Dönges, O. Meusel, H. Podlech, K. Schulte-Urlichs
IAP, Frankfurt am Main, Germany
K. Schulte-Urlichs, K.I. Thoma
GSI, Darmstadt, Germany

At Goethe-University, a novel concept of heating metallic cathodes is currently under investigation. In the scope of the ARIES collaboration WP16, an RF-modulated electron gun was developed and manufactured for application in electron lenses for space charge compensation. The goal of this project is to increase the intensity of primary beams, especially in low energy booster synchrotrons like the SIS18 and SIS100 at GSI/FAIR or the SPS at CERN. The gun was designed to produce electron currents of 10 A at extraction voltages of 30 kV. The tungsten electron emitter (TE²) and the grid electrode were designed and manufactured to be integrated in the extractor of the original volume type ion source. Significant effort was put into a robust and flexible design with highly reliable key components. The cathode is heated by a plasma stream generated in the plasma chamber of the source. Different heating options of the cathode are currently being studied. This contribution presents the working principles of the electron gun and first measurements results of cathode heating.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS018

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Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 26 June 2022

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MOPOMS019

The New SPARC_LAB RF Photo-Injector

operation, solenoid, vacuum, quadrupole

671

D. Alesini, M.P. Anania, M. Bellaveglia, A. Biagioni, F. Cardelli, G. Costa, M. Del Franco, G. Di Pirro, L. Faillace, M. Ferrario, G. Franzini, A. Gallo, A. Giribono, L. Piersanti, L. Sabbatini, A. Stella, A. Vannozzi
INFN/LNF, Frascati, Italy
A. Battisti, E. Chiadroni, G. Di Raddo, A. Liedl, V.L. Lollo, L. Pellegrino, R. Pompili, S. Romeo, V. Shpakov, C. Vaccarezza, F. Villa
LNF-INFN, Frascati, Italy
M. Carillo, E. Chiadroni
Sapienza University of Rome, Rome, Italy
A. Cianchi, M. Galletti
Università di Roma II Tor Vergata, Roma, Italy

A new RF photo-injector has been designed, realized and successfully installed at the SPARC_LAB facility (INFN-LNF, Frascati, Rome). It is based on a 1.6 cell RF gun fabricated with the new brazing free technology recently developed at the National Laboratories of Frascati. The electromagnetic design has been optimized to have a full compensation of the dipole and quadrupole field components introduced by the coupling hole with an improvement of the effective pumping speed with two added pumping ports. The gun is overcoupled (\beta=2) to reduce the filling time and to allow the operation with short RF pulses. The overall injector integrates a new solenoid with a remote control of the transverse position and a variable skew quadrupole for the compensation of residual quadrupole field components. It also allows an on axis laser injection system with the last mirror in air, and the possibility of a future integration of an X/C band cavity linearizer. In the paper we report the main characteristics of the electromagnetic and mechanical design and the low and high power test results that shows the extremely good perfomances of the new device.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS019

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Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022

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MOPOMS020

Dark Current Studies for a High Gradient SW C-Band RF Gun

cathode, simulation, solenoid, electron

675

F. Cardelli, D. Alesini, L. Faillace, A. Giribono, A. Vannozzi
INFN/LNF, Frascati, Italy
G. Di Raddo
LNF-INFN, Frascati, Italy
T.G. Lucas
PSI, Villigen PSI, Switzerland

It is now well-established that for the generation of very high brightness beams, required for fourth generation light sources, it is highly advantageous to use injectors based on Radiofrequency photo-guns with very high peak electric fields on the cathode (>120 MV/m). This very high surface electric field leads to the generation of undesirable electrons due to the field emission effect. The emitted electrons can be captured and propagate along the Linac forming a dark current beam, leading to background radiation that can damage the instrumentation and radioactivate components. Consequently, it is important that the emission of these electrons, and their subsequent transportation, is carefully evaluated. Recently, in the framework of the I-FAST project, a high gradient, standing wave, C-band (5712 MHz) RF photogun has been designed and will be realized soon. In this paper, the results of dark current studies and simulations are illustrated. The transport efficiency and the spectrum of the dark current have been evaluated by Particle-In-Cell simulations for different cathode peak field values considering also the effect of the focusing solenoid on the dark current beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS020

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022

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MOPOMS021

The New C Band Gun for the Next Generation RF Photo-Injectors

cathode, brightness, operation, quadrupole

679

D. Alesini, M. Ferrario, A. Giribono, A. Gizzi, L. Piersanti, A. Vannozzi
INFN/LNF, Frascati, Italy
F. Cardelli, G. Di Raddo, L. Faillace, S. Lauciani, A. Liedl, L. Pellegrino, C. Vaccarezza
LNF-INFN, Frascati, Italy
G. Castorina
AVO-ADAM, Meyrin, Switzerland
M. Croia
ENEA Casaccia, Roma, Italy
L. Ficcadenti
INFN-Roma, Roma, Italy
G. Pedrocchi
SBAI, Roma, Italy

Funding: European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730 and INFN Commission V.
RF photo-injectors are widely used in modern facilities, especially in FEL, as very low-emittance and high-brightness electron sources. Presently, the RF technology mostly used for RF guns is the S band (3 GHz) with typical cathode peak fields of 80-120 MV/m and repetition rates lower than 120 Hz. There are solid reasons to believe that the frequency step-up from S band to C band (6 GHz) can provide a strong improvement of the beam quality due to the potential higher achievable cathode field (>160 MV/m) and higher repetition rate (that can reach the kHz level). In the contest of the European I.FAST project, a new C band gun has been designed and will be realized and tested. It is a 2.5 cell standing wave cavity with a four port mode launcher, designed to operate with short RF pulses (<300 ns) and cathode peak field larger than 160 MV/m. In the paper we present the electromagnetic and thermo-mechanical design and the results of the prototyping activity and rf measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS021

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Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022

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MOPOMS022

Studies of a Ka-Band High Power Klystron Amplifier at INFN-LNF

klystron, cavity, electron, focusing

683

M. Behtouei, L. Faillace, A. Mostacci, B. Spataro
LNF-INFN, Frascati, Italy
F. Bosco, M. Carillo, M. Migliorati, A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy
F. Di Paolo, S. Fantauzzi, A. Leggieri, F. Marrese, L. Valletti
Università degli Studi di Roma "Tor Vergata", Roma, Italy
G. Torrisi
INFN/LNS, Catania, Italy

In the framework of the Compact Light XLS project, a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM₀₁₀ mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6 MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high- power microwave window for a Ka-band klystron providing 16MW of peak power.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS022

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Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 10 July 2022

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MOPOMS028

Stability and Lifetime Studies of Carbon Nanotubes for Electron Cooling in ELENA

electron, cathode, proton, antiproton

699

B. Galante, G. Tranquille
CERN, Meyrin, Switzerland
J. Resta-López, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J. Resta-López
ICMUV, Paterna, Spain

Funding: Work supported by EU Horizon 2020 research and innovation programme under the Marie Sk’odowska-Curie grant agreement No 721559.
Electron cooling is a fundamental process to guarantee beam quality in low energy antimatter facilities. In ELENA, the electron cooler reduces the emittance blow-up of the antiproton beam so that a focused and bright beam can be delivered to the experiments at the unprecedentedly low energy of 100 keV. To achieve a cold beam at this low energy, the electron gun must emit a monoenergetic and relatively intense electron beam. An optimization of the electron gun involving a cold cathode is studied to investigate the feasibility of using carbon nanotubes (CNTs) as cold electron field emitters. CNTs are considered among the most promising field emitting materials. However, stability data for emission over hundreds of hours, as well as lifetime and conditioning process studies to ensure optimal performance, are still incomplete or missing, especially if the aim is to use them in operation. This contribution reports experiments that characterize these properties and assess whether CNTs are suitable to be used as cold electron field emitters for many hundreds of hours.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS028

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Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022

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MOPOMS052

6 MeV Novel Hybrid (Standing Wave - Traveling Wave) Photo-Cathode Electron Gun for a THz Superradiant FEL

electron, cathode, klystron, experiment

760

A. Nause, L. Feigin, A. Friedman, A. Weinberg
Ariel University, Ariel, Israel
A. Fukasawa, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
B. Spataro
LNF-INFN, Frascati, Italy

A novel 6 MeV hybrid photo injector was designed and commissioned at Ariel University in Israel as an on-going collaboration with UCLA. This unique, new generation design provides a radically simpler approach to RF feeding of a gun/buncher system, leading to a much shorter beam via velocity bunching owed to an attached traveling wave section of the photo-injector. This design results in better performance in beam parameters, providing a high quality electron beam, with energy of 6 MeV, emittance of less than 3 ’m, and a 150 fs pulse duration at up to 1 nC per pulse. The Hybrid gun is driven by a SLAC XK5 Klystron as the high power RF source, and third harmonic of a fs level IR Laser amplifier (266 nm) to extract electrons from the Cathode. The unique e-gun will produce a bunched electron pulse to drive a THz FEL, which will operate at the super-radiance regime, and therefore requires extraordinary beam properties. It will also be used for MeV UED experiments in a separate line using a dogleg section. Here we describe the gun and presents experimental results from the gun and its sub-systems, including energy and charge measurements, compared with the design simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS052

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Received ※ 11 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022

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TUOZSP3

The European ERL Roadmap

electron, FEL, linac, SRF

831

A. Hutton
JLab, Newport News, Virginia, USA
M. Klein
The University of Liverpool, Liverpool, United Kingdom
B.C. Kuske
HZB, Berlin, Germany

Funding: AH supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177
Following the European Strategy process in 2019, five Roadmap Panels were set up to prepare the technologies needed for future accelerators and colliders: high-field magnets, SRF, muon colliders, plasma wakefield accelerators and Energy Recovery Linacs (ERLs). The ERL Roadmap Panel, consisting of ERL experts from around the world, first developed an overview of current and future ERLs. From this it was possible to carry out a gap analysis to see what R&D would be needed, from which the Roadmap could be developed. The European ERL Roadmap focused on three main aspects: 1) the continuation and development of facility programs for which no additional funds are needed, S-DALINAC in Darmstadt and MESA in Mainz; 2) technology development for room-temperature HOM damping and twin-axis SRF cavities; 3) the timely upgrade of bERLinPro for 100 mA current and the construction of PERLE at Orsay as a dedicated 10 MW power multi-turn facility. The roadmap entails a vision of future energy frontier electron-positron and electron-hadron collider and describes a high quality ERL program for 4.4 K SRF technology at high Q₀. The presentation will address the ERL Roadmap process and result in detail.

Slides TUOZSP3 [2.868 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOZSP3

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Received ※ 02 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 29 June 2022

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TUPOST056

Multi-Objective Bayesian Optimization at SLAC MeV-UED

electron, controls, detector, timing

995

F. Ji, A.L. Edelen, R.J. England, P.L. Kramer, D. Luo, C.E. Mayes, M.P. Minitti, S.A. Miskovich, M. Mo, A.H. Reid, R.J. Roussel, X. Shen, X.J. Wang, S.P. Weathersby
SLAC, Menlo Park, California, USA

SLAC MeV-UED, part of the LCLS user facility, is a powerful ’electron camera’ for the study of ultrafast molecular structural dynamics and the coupling of electronic and atomic motions in a variety of material and chemical systems. The growing demand of scientific applications calls for rapid switching between different beamline configurations for delivering electron beams meeting specific user run requirements, necessitating fast online tuning strategies to reduce set up time. Here, we utilize multi-objective Bayesian optimization(MOBO) for fast searching the parameter space efficiently in a serialized manner, and mapping out the Pareto Front which gives the trade-offs between key beam parameters, i.e., spot size, q-resolution, pulse length, pulse charge, etc. Algorithm, model deployment and first test results will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST056

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022

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TUPOPT025

Concept of Electron Beam Diagnostics for PolFEL

radiation, FEL, electron, diagnostics

1055

A.I. Wawrzyniak, G.W. Kowalski, A.M. Marendziak, R. Panaś
NSRC SOLARIS, Kraków, Poland
A. Curcio
CLPU, Villamayor, Spain
P.J. Czuma, M. Krakówiak, P. Krawczyk, R. Kwiatkowski, S. Mianowski, R. Nietubyc, M. Staszczak, J. Szewiński, M. Terka, M. Wójtowicz
NCBJ, Świerk/Otwock, Poland
K. Łasocha
Jagiellonian University, Kraków, Poland

PolFEL - Polish Free Electron Laser will be driven by a continuous wave superconducting accelerator consist-ing of low emittance superconducting RF electron gun, four accelerating cryomodules, bunch compressors, beam optics components and diagnostic elements. The acceler-ator will split in three branches leading to undulators pro-ducing VUV, IR and THz radiation, respectively. Two accelerating cryomodules will be installed before a dogleg directing electron bunches towards IR and THz branches. Additional two cryomodules will be placed in the VUV branch accelerating electron bunches up to 185 MeV at 50 kHz repetition rate. Moreover, the electron beam after passing the VUV undulator will be directed to the Inverse Compton Scattering process for high energy photons experiments in a dedicated station. In order to measure and optimise the electron beam parameters along the entire accelerator the main diagnostics components like BPMs, charge monitors, YAG screens, coherent diffrac-tion radiation (CDR) monitors and beam loss monitors are foreseen. Within this presentation the concept of the electron beam diagnostics will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT025

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Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022

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TUPOPT035

Introduction of Westwood Linear Accelerator Test Facility in University of California Los Angeles

laser, electron, FEL, klystron

1085

Y. Sakai, G. Andonian, O. Camacho, A. Fukasawa, G.E. Lawler, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, O. Williams
UCLA, Los Angeles, California, USA

Funding: U.S. DOE: DE-SC0009914 U.S. DOD: DARPA GRIT Contract 20204571 U.S. DOE: DE-SC0020409 - Cryo RF
An electron linear accelerator test facility located on UCLA’s southwest campus in Westwood, SAMURAI, is presently being constructed. A RF-based accelerator consists of a compact, 3 MeV S-band hybrid gun capable of velocity bunching to bunch lengths in the 100s fs range with 100s pC of charge. This beam is accelerated by an 1.5 m S-band linac with a peak output energy of 30 MeV which can be directed to either a secondary beamline or remain on the main beamline for final acceleration by a SLAC 3 m S-band linac to an energy of 80 MeV. Further acceleration by advanced boosters such as a cryo-cooled C-band structure or numerous optical or wakefield methods is under active investigation. In combination with a 3 TW Ti:Sapphire laser, initial proof of principle experiments will be conducted on topics including the ultra-compact x-ray free-electron laser, advanced dielectric wakefield acceleration, bi-harmonic nonlinear inverse Compton scattering, and various radiation detectors. Furthermore, development of a tertiary beamline based on an ultra low emittance, cryo-cooled gun will eventually enable two-beam experiments, expanding the facility’s unique experimental capabilities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT035

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 24 June 2022

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TUPOPT066

KEK LUCX Facility Laser-to-RF&RF-to-RF Stability Study and Optimization

laser, feedback, LLRF, timing

1167

K. Popov
Sokendai, Ibaraki, Japan
A. Aryshev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

KEK LUCX facility* is a linear accelerator devoted to the beam instrumentation R&Ds for present and future accelerator systems and colliders including ILC. According to the ILC TDR**, it is necessary to achieve RF-gun Laser-to-RF&RF-to-RF phase stability of 0.35°(RMS) and amplitude stability of 0.07%(RMS) with implementation of the Digital LLRF feedback based on commercially available FPGA board and digital trigger system. As the first step to achieve ILC stability level at KEK-LUCX facility, present Laser-to-RF&RF-to-RF phase and amplitude jitters were measured using time- and frequency-domain techniques. After that, jitter influence on beam parameters after RF-gun and main solenoid magnet was simulated with ASTRA tracking code*** and results were cross-checked during LUCX facility beam operation. Finally, stable digital trigger system and digital LLRF feedback based on SINAP EVG&EVR and RedPitaya SIGNALlab-250 modules were implemented. This report demonstrates the results of Laser-to-RF&RF-to-RF phase and amplitude jitter measurements cross-checked with ASTRA simulation and real beam parameters measurements before and after LUCX facility stabilization.
References
*A. Aryshev et al., Appl. Phys. Lett. 111, 033508 (2017).
**International Linear Collider Reference Design Report, ILC-REPORT-2007-001, 2007.
***https://www.desy.de/~mpyflo/

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT066

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022

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TUPOPT070

Surrogate Modelling of the FLUTE Low-Energy Section

simulation, network, electron, controls

1182

C. Xu, E. Bründermann, A.-S. Müller, A. Santamaria Garcia, J. Schäfer
KIT, Karlsruhe, Germany

Funding: Supported by the Helmholtz Association (Autonomous Accelerator, ZT-I-PF-5-6) and the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology".
Numerical beam dynamics simulations are essential tools in the study and design of particle accelerators, but they can be prohibitively slow for online prediction during operation or for systematic evaluations of new parameter settings. Machine learning-based surrogate models of the accelerator provide much faster predictions of the beam properties and can serve as a virtual diagnostic or to augment data for reinforcement learning training. In this paper, we present the first results on training a surrogate model for the low-energy section at the Ferninfrarot Linac- und Test-Experiment (FLUTE).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT070

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Received ※ 30 May 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022

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TUPOTK053

Design Progress of High Efficiency Klystron for CEPC LINAC

klystron, simulation, cavity, linac

1339

Z.D. Zhang, Y.L. Chi, D. Dong, M. Iqbal, G. Pei, S.C. Wang, O. Xiao, S. Zhang, Z.S. Zhou
IHEP, Beijing, People’s Republic of China
S. Zhang, Z.D. Zhang
UCAS, Beijing, People’s Republic of China

The injector linear accelerator (LINAC) for the CEPC requires a higher efficiency klystron with 80MW output power than S band 65MW pulsed klys-tron currently operating in LINAC of BEPCII to reduce energy consumption and cost. The efficiency is ex-pected to improve from the currently observed 42% to more than 55% and output power will be improved from 65MW to more than 80MW with same operation voltage. In this paper, BAC bunching method is ap-plied for klystron efficiency improvement. The optimi-zation of the gun and solenoid parameters is complet-ed with 2-D code DGUN and then 3-D code CST. The preliminary design of the cavity parameters is also completed in 1-D disk model based AJDISK code and then further checked by 2-D code EMSYS. Finally, new klystron prototype will be fabricated in Chinese com-pany after design parameters are determined.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK053

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Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022

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WEOYSP2

First Electron Beam of the ThomX Project

linac, HOM, electron, emittance

1632

C. Bruni, M. Alkadi, J-N. Cayla, I. Chaikovska, S. Chancé, V. Chaumat, O. Dalifard, N. Delerue, K. Dupraz, M. El Khaldi, N. ElKamchi, E.E. Ergenlik, P. Gauron, A. Gonnin, E. Goutierre, H. Guler, M. Jacquet, V. Kubytskyi, P. Lepercq, F. Letellier-Cohen, J.C. Marrucho, B. Mercier, E. Mistretta, H. Monard, A. Moutardier, M. Omeich, V. Soskov, F. Wicek
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

Funding: The present work is financed by the French National Research Agency (ANR) under the Equipex program ANR-10-EQPX-0051.
The ThomX accelerator beam commissioning phase is now ongoing. The 50 MeV electron accelerator complex consists of a 50 MeV linear accelerator and a pulsed mode ring. It is dedicated to the production of X-rays by Compton backscattering. The performance of the beam at the interaction point is demanding in terms of emittance, charge, energy spread and transverse size. The choice of an undamped ring in pulsed mode also stresses the performance of the beam from the linear accelerator. Thus, commissioning includes a beam based alignment and a simulation/experimental matching procedure to reach the X-ray beam requirements. We will present the first 50 MeV electron beam obtained with ThomX and its characteristics.
on behalf of the ThomX collaboration : ThomX collaboration, https://thomx.ijclab.in2p3. fr/collaboration-thomx/, [Online; accessed 19-May- 2022].

Slides WEOYSP2 [80.558 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP2

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Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 06 July 2022

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WEPOPT025

Flat Beam Generation with the Phase Space Rotation Technique at KEK-STF

emittance, collider, experiment, cathode

1897

M. Kuriki, Z.J. Liptak
HU/AdSM, Higashi-Hiroshima, Japan
S. Aramoto
Hiroshima University, Higashi-Hiroshima, Japan
H. Hayano, X.J. Jin, Y. Seimiya, N. Yamamoto, Y. Yamamoto
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
M. Washio
RISE, Tokyo, Japan

Flat beam generation from angular momentum dominated beam with a phase-space rotation technique is an unique method to manipulate the phase-space distribution of beam. As an application, the asymmetric emittance beam generation for linear colliders is considered to compensate the Beamstrahlung effect at Interaction point. By using this technique, the asymmetric beam can be generated directly with the injector, instead of radiation damping with a huge damping ring. We present the result of a proof-of-principle experiment at KEK-STF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT025

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022

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WEPOPT065

Simulations of the Upgraded Drive-Beam Photoinjector at the Argonne Wakefield Accelerator

solenoid, emittance, laser, electron

2015

E.A. Frame, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
S.Y. Kim, X. Lu, J.G. Power, D.S. Scott, E.E. Wisniewski
ANL, Lemont, Illinois, USA

Funding: Department of Energy
The Argonne Wakefield Accelerator (AWA) is planning to upgrade its photoinjector for the drive-beam accelerator. The main goal of the upgrade is to improve the beam brightness using a symmetrized RF-gun cavity. In the process, the photoinjector was reconfigured and some of the solenoid magnets redesigned. A challenging aspect of this optimization is that the injector should be able to produce bright low-charge (~1 nC) bunches while also being capable of operating at high-charge (~50 nC) bunches. This paper will discuss the optimization of the beam dynamics for the low- and high-charge cases and explore the performances of the proposed configuration using a model of the full AWA drive-beam beamline including 3D field maps for the external electromagnetic fields. The optimizations are performed with ASTRA and the DEAP toolbox and with OPAL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT065

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Received ※ 08 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022

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WEPOTK003

Status of the Development of the Electron Lens for Space Charge Compensation at GSI

electron, cathode, solenoid, space-charge

2027

K. Schulte-Urlichs, D. Ondreka, P.J. Spiller, K.I. Thoma
GSI, Darmstadt, Germany
M. Droba, T. Dönges, O. Meusel, H. Podlech
IAP, Frankfurt am Main, Germany

At GSI a prototype electron lens for space charge (SC) compensation is currently being designed and main components as the RF-modulated electron gun are already under commissioning. The goal of this project is the (partial) compensation of SC forces within the ion beam by an overlapping electron beam. This may help to increase the intensity of primary beams, especially in the FAIR facility and potentially all large synchrotrons operated at the SC limit. For an effective SC compensation, the generated electron beam needs to follow the transverse and longitudinal beam profile of the ion bunch structure. The requirements are maximum currents of 10 A and grid modulation to cover a broad frequency range from 400 kHz to 1 MHz. The RF-modulated electron gun was designed and manufactured in the scope of the ARIES collaboration and is currently being tested at the E-Lens Lab of Goethe University Frankfurt. A dedicated test bench was built for commissioning of the major e-lens components and diagnostics. In this contribution the overall set-up will be presented putting special emphasis on the beam dynamics and collector design as well as as well as simulation results of the electron gun.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK003

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Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022

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WEPOTK060

Prospects of Ultrafast Electron Diffraction Experiments at Sealab

electron, experiment, SRF, cavity

2201

B. Alberdi-Esuain, J.-G. Hwang, T. Kamps, A. Neumann, J. Völker
HZB, Berlin, Germany
T. Kamps
HU Berlin, Berlin, Germany

Ultrafast Electron Diffraction (UED) is a pump-probe experimental technique that aims to image the structural changes that happen in a target structure due to photo-excitation. Development of MeV UED capabilities is one of the main objectives at Sealab, a superconducting RF accelerator facility being commissioned in Helmholtz-Zentrum Berlin. In order to perform UED experiments, the optimization of temporal resolution is of the utmost importance. The composition of the SRF Photoinjector, currently the main beam-line in Sealab, offers superb flexibility to manipulate the longitudinal phase-space of the electron bunch. At the same time, the CW operation of the accelerator provides an enhanced beam stability compared to warm guns, together with MHz repetition rates. This work aims to show the capacity of the SRF Photoinjector in Sealab to reach the required temporal resolution and explain the development and current status of the necessary tools to perform UED experiments at the facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK060

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Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022

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WEPOMS024

Present Status of the Injector at the Compact ERL at KEK

FEL, emittance, linac, operation

2296

O.A. Tanaka, T. Miyajima, T. Tanikawa
KEK, Ibaraki, Japan

The Compact ERL at KEK is a test accelerator to develop ERL technologies and their possible applications. The first target of injector operation to demonstrate IR-FEL was to generate high bunch charge electron beams with low longitudinal emittance and short bunch length. In 2020, the injector was operated with the bunch charge of 60 pC, the DC gun voltage of 480 kV, the injector energy of 5 MeV and the bunch length of 2 ps rms, and the required beam quality for the IR-FEL has been achieved for a single-pass operation mode. The next target is to demonstrate IR-FEL generation for recirculation mode. The injector energy is decreased to 3.5 MeV due to a limitation of the energy ratio between injection and recirculation beams. Moreover, the DC gun voltage decreases to 390 kV due to the troubles of the DC gun. Therefore, control of the space charge effect is more important to design and optimize the beam transport condition of the injector. In this report, a strategy of the injector optimization together with its realization results and future prospects are summarized.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS024

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 21 June 2022

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WEPOMS055

Cathode Space Charge in Bmad

space-charge, cathode, simulation, controls

2380

N. Wang
Cornell University, Ithaca, New York, USA
J.A. Crittenden, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes
SLAC, Menlo Park, California, USA

Funding: This project was supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
We present an implementation of charged particle tracking with the cathode space charge effect included which is now openly available in the Bmad toolkit for charged particle simulations. Adaptive step size control is incorporated to improve the computational efficiency. We demonstrate its capability with a simulation of a DC gun and compare it with the well-established space charge code Impact-T.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS055

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 05 July 2022

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THPOST006

Simulations of the Suitability of a DC Electron Photogun and S-Band Accelerating Structure as Input to an X-Band Linac

simulation, emittance, electron, acceleration

2445

S.D. Williams, R.P. Rassool, S.L. Sheehy, G. Taylor, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
R. Auchettl, R.T. Dowd
AS - ANSTO, Clayton, Australia

Work has been underway for some time to design a compact electron beamline utilising X-band linear accelerating structures in the new Melbourne X-band Laboratory for Accelerators and Beams (X-LAB). The original design utilised an S-band RF photogun as an input to a pair of high gradient X-band linear accelerating structures, but we have been motivated to investigate an alternative starting section to allow for initial testing. This will utilise a DC photogun and S-band accelerating structure similar to those used at the Australian Synchrotron. Simulation results incorporating space charge of a beamline composed of a DC photogun, S-band accelerating structures, and two high gradient X-band structures will be presented. These simulation results will be optimised for minimum emittance at the end of the beamline.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST006

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Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 22 June 2022

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THPOST007

Slow-Control Loop to Stabilize the RF Power of the FLUTE Electron Gun

controls, cavity, electron, LLRF

2449

M.-D. Noll, A. Böhm, J. Jelonek, I. Križnar, O. Manzhura, A.-S. Müller, R. Ruprecht, M. Schuh, N.J. Smale
KIT, Karlsruhe, Germany

The linear accelerator FLUTE (Far Infrared Linac and Test Experiment) at KIT serves as a test facility for accelerator research and for the generation of ultra-intense coherent THz radiation. To achieve stable THz photon energy and optimal beam trajectory, the energy of the electrons emitted from the RF photo-injector must be stable. The accelerating voltage of the RF cavity has been shown to be a significant influencing factor. Here, we report on the development of a slow closed-loop feedback system to stabilize the RF power and thus the accelerating voltage in the RF photo-injector cavity. With this closed-loop feedback system the relative standard deviation of the RF power in the cavity can be improved by 8.5 %.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST007

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Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022

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THPOST017

Physical Design of a 10 MeV High Scanning Frequency Irradiation Electron Linear Accelerator

electron, radiation, simulation, kicker

2476

S. Zhang, Z.D. Zhang
UCAS, Beijing, People’s Republic of China
Y.L. Chi, M. Iqbal, J.R. Zhang, S. Zhang, Z.D. Zhang, Z.S. Zhou
IHEP, Beijing, People’s Republic of China

A compact 10 MeV irradiation S-band electron linear accelerator has been proposed to carry out the electron radiation effect test of materials and devices. The Linac includes a standing wave pre-buncher, a traveling wave bunching accelerating structure. The traveling wave accelerating structure uses a 5MW klystron as RF source and provides electron beam energy 3.5-10MeV and average current 0.01-1mA. The required irradiation scanning frequency is very high, up to 100Hz and irradiation area is large (200mm×200mm). To meet the requirements, a novel beam scanning system, including one kicker for horizontal scanning and one magnet for vertical scanning, have been proposed. This paper presents the physical design of the 10MeV electron Linac and beam dynamics simulation results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST017

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 14 June 2022

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THPOST019

Generation of Transversely Uniform Bunches from a Gaussian Laser Spot in a Photoinjector for Irradiation Experiments

space-charge, laser, linac, electron

2483

L.A. Dyks, P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
P. Burrows
JAI, Oxford, United Kingdom
R. Corsini, A. Latina
CERN, Meyrin, Switzerland

Beams of uniform transverse beam profile are desirable for a variety of applications such as irradiation experiments. The generation of beams with such profiles has previously been investigated as a method of reducing emittance growth. These methods, however, often use complicated optics setups or short, femtosecond laser pulse lengths. In this paper, we demonstrate that if ultra low emittance is not the target of the photoinjector, it is possible to produce transversely uniform beam profiles using a simple Gaussian laser, with a bunch length of a few picoseconds, utilising space-charge effects only.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST019

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Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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THPOST021

Beam Dynamics Simulations of Linear Accelerator for Natural Rubber Vulcanization at Chiang Mai University

electron, simulation, linac, cathode

2491

J. Saisut, S. Rimjaem, C. Thongbai
Chiang Mai University, Chiang Mai, Thailand
M. Jitvisate
Suranaree University of Technology, Nakhon Ratchasima, Thailand
S. Rimjaem, J. Saisut, C. Thongbai
ThEP Center, Commission on Higher Education, Bangkok, Thailand

The Linear accelerator system for natural rubber vulcanization has been developed at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The main components of the accelerator system consist of a DC electron gun with a thermionic cathode, an RF linear accelerator, an RF system, a control system, and an irradiation system. The electron beam properties for natural rubber vulcanization are predicted from the beam dynamics simulation starting from a cathode to the titanium exit window. The electron beam generation and the particle in cell simulation inside the DC electron gun are performed using CST Studio Suit software. The electron distribution at the gun exit from the CST output is covered to be an input distribution of the ASTRA beam dynamics simulation program. The electron beam enters linac and is accelerated by RF filed inside the linac. The ASTRA simulation code is used to track electron trajectories including the space-charge interaction and the simulation starts from linac entrance to the exit windows. The electron beam properties for various conditions are evaluated and will be used for further simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST021

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 03 July 2022

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THPOST040

Commissioning of an X-Band Cavity for Longitudinal Phase Space Linearization at UCLA PEGASUS Laboratory

cavity, electron, linac, emittance

2533

P.E. Denham, P. Musumeci, A. Ody
UCLA, Los Angeles, USA

This paper discusses the commissioning of an X-band (9.6 Ghz) linearizer cavity at the UCLA PEGASUS beamline. The photoinjector gun and booster linac operate at S-band (2.856 GHz) and the linearizer cavity can be used to compensate temporally correlated energy spread inherited by the use of relatively long (many ps) laser pulses at the photocathode. The cavity is comprised of 7 cells for a total length of a 9.45 cm, and is installed in the drift section between the gun and the linac. It can be used to remove higher order correlations and minimize the beam energy spread of 13 ps long beams to 10^-4.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST040

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Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 27 June 2022

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THPOST046

CrYogenic Brightness-Optimized Radiofrequency Gun (CYBORG)

cryogenics, cathode, cavity, brightness

2544

G.E. Lawler, A. Fukasawa, N. Majernik, J.R. Parsons, J.B. Rosenzweig, Y. Sakai, A. Suraj
UCLA, Los Angeles, California, USA

Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132 and DOE Contract DE-SC0020409
Producing higher brightness beams at the cathode is one of the main focuses for future electron beam applications. For photocathodes operating close to their emission threshold, the cathode lattice temperature begins to dominate the minimum achievable intrinsic emittance. At UCLA, we are designing a radiofrequency (RF) test bed for measuring the temperature dependence of the mean transverse energy (MTE) and quantum efficiency for a number of candidate cathode materials. We intend to quantify the attainable brightness improvements at the cathode from cryogenic operation and establish a proof-of-principle cryogenic RF gun for future studies of a 1.6-cell cryogenic photoinjector for the UCLA ultra compact XFEL concept (UC-XFEL). The test bed will use a C-band 0.5-cell RF gun designed to operate down to 45 K, producing an on-axis accelerating field of 120 MV/m. The cryogenic system uses conduction cooling and a load-lock system is being designed for transport and storage of air-sensitive high brightness cathodes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST046

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022

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THPOPT005

Field Enhanced, Compact S-Band Gun Employing a Pin Cathode

electron, cathode, cavity, multipactoring

2567

R. Bazrafshan, T. Rohwer
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
M. Fakhari, K. Flöttmann, F.X. Kaernter
DESY, Hamburg, Germany
N.H. Matlis
CFEL, Hamburg, Germany

S-band RF-guns are highly developed for production of low emittance relativistic electron bunches, but need powerful klystrons for driving. Here, we present the design and first experimental tests of a compact S-band gun, which can accelerate electrons up to 180 keV powered by only 10 kW from a compact rack-mountable solid-state amplifier. A pin-cathode is used to enhance the RF electric field on the cathode up to 100 MV/m as in large-scale S-band guns. An electron bunch is generated through photoemission off a flat copper surface on the pin excited by a UV laser pulse followed by a focusing solenoid producing a low emittance bunch with 0.1 mm mrad transverse emittance for up to 100 fC bunch charge. We are currently in the conditioning phase of the gun and first experiments show good agreement with simulations. The compact gun will serve three purposes: (i) it can be used directly for ultrafast electron diffraction; (ii) as an injector into a THz booster producing 0.3MeV to 2 MeV electron bunches for ultrafast electron diffraction; (iii) The system in (ii) serves as an injector into a THz linear accelerator producing a 20 MeV beam for the AXSIS X-ray source project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT005

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Received ※ 21 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022

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THPOPT019

Multi-Alkali Antimonide Photocathode Development for High Brightness Beams

cathode, SRF, brightness, electron

2610

S. Mistry, T. Kamps, J. Kühn, C. Wang
HZB, Berlin, Germany
T. Kamps
HU Berlin, Berlin, Germany
C. Wang
University Siegen, Siegen, Germany

Funding: This work is funded by the DFG CO 1509/10-1 | MI 2917/1-1
Photocathode R&D at the Helmholtz-Zentrum Berlin (HZB) is driven by the motivation to produce high brightness electron beams for the SRF photoinjector test facility, Sealab/ bERLinPro. Multi-alkali antimonides are the choice photocathode material due to high quantum efficiency (QE) and low intrinsic emittance in the visible range. In this work a more robust alternative to the tried and tested Cs-K-Sb is considered. Na-K-Sb offers similar advantages to Cs-K-Sb including, high QE at green wavelengths but moreover, it offers excellent stability at elevated temperatures. This property could lengthen the cathode lifetime by enhancing the robustness of the photocathode inside the SRF gun. In this work, a status report showcasing first results towards the development of a growth procedure for Na-K-Sb is presented by means of spectral response and XPS measurements conducted in the HZB photocathode lab.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT019

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Received ※ 03 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 04 July 2022

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THPOPT020

Status and Plans for the New CLS Electron Source Lab

electron, operation, linac, radiation

2614

M.J. Boland, D. Bertwistle, F. Le Pimpec
CLS, Saskatoon, Saskatchewan, Canada
X.F.D. Stragier
TUE, Eindhoven, The Netherlands

The Canadian Light Source (CLS) has recently created a new Electron Source Lab (ESL) that can run independently from user operations. A section of the old Saskatchewan Accelerator Laboratory experimental nuclear physics tunnels has been rebuilt with new shielding and a separate entrance. The laboratory will be used to prepare an operational spare electron gun for the 250 MeV linac. In addition, there are plans to develop RF guns for a future branch line to inject into the linac and for possible short pulse production. This paper will give an overview of the ESL space and the first electron guns which plan to be installed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT020

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Received ※ 16 June 2022 — Revised ※ 29 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 08 July 2022

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THPOPT022

Study on QE Evolution of Cs₂Te Photocathodes in ELBE SRF Gun-II

cathode, SRF, operation, vacuum

2617

R. Xiang, A. Arnold, S. Ma, P. Michel, P. Murcek, A.A. Ryzhov, J. Schaber, J. Teichert, P.Z. Zwartek
HZDR, Dresden, Germany

The quality of the photocathodes is critical for the sta-bility and reliability of the photoinjector’s operation. Thanks to the robust magnesium and Cs₂Te photocathodes, SRF gun-II at HZDR has been proven to be a suc-cessful example in CW mode for high current user operation. In this contribution, we will present our observation of the QE evolution of Cs₂Te photocathodes during SRF gun operation. The variables including substrate surface, film thickness, Cs/Te stoichiometric, multipacting, RF loading and charge extract are considered in the analysis.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT022

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Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 06 July 2022

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THPOPT025

Photocathode Stress Test Bench at INFN LASA

cathode, laser, electron, operation

2627

D. Sertore, D. Giove, L. Monaco
INFN/LASA, Segrate (MI), Italy
A. Bacci, F. Canella, S. Cialdi, I. Drebot, D. Giannotti, L. Serafini
INFN-Milano, Milano, Italy
D. Cipriani, E. Suerra
Università degli Studi di Milano, Milano, Italy
G. Galzerano
POLIMI, Milano, Italy
G. Guerini Rocco
Università degli Studi di Milano & INFN, Segrate, Italy

A UHV test bench based on a 100 kV DC gun and a 100 MHz repetition rate laser has been setup up at INFN LASA to test Cs₂Te photocathodes. This operation mode is the baseline of the BriXSinO project, currently in the design phase in our laboratory, and the qualification of the Cs₂Te photocathodes is a key issue. In this paper, we present the recent advances in the different aspects of this R&D activity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT025

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Received ※ 10 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 20 June 2022

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THPOPT027

R&D on High QE Photocathodes at INFN LASA

cathode, FEL, operation, electron

2633

D. Sertore, M. Bertucci, L. Monaco
INFN/LASA, Segrate (MI), Italy
G. Guerini Rocco
Università degli Studi di Milano & INFN, Segrate, Italy
S.K. Mohanty, H.J. Qian, F. Stephan
DESY Zeuthen, Zeuthen, Germany

We present the recent activities on antimonide and telluride alkali based photocathodes at INFN LASA. The R&D on Cs₂Te materials is focused on investigating effects of material thickness and growth procedures on the photocathodes performances during operation in RF guns. We aim to improve thermal emittance and long term stability of these films. The more recent work on alkali antimonide showed the need for substantial improvements in stability and QE during operation. We present here our recent achievements and plans for future activities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT027

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Received ※ 09 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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THPOPT036

New Microwave Thermionic Electron Gun for APS Upgrade: Test Results and Operation Experience

linac, cathode, operation, injection

2665

S.V. Kutsaev, R.B. Agustsson, A.C. Araujo Martinez, R.D. Berry, O. Chimalpopoca, A.Y. Murokh, M. Ruelas, A.Yu. Smirnov, S.U. Thielk
RadiaBeam, Santa Monica, California, USA
J.E. Hoyt, W.G. Jansma, A. Nassiri, Y. Sun, G.J. Waldschmidt
ANL, Lemont, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Basic Energy Science, under contracts DE-SC0015191 and DE- AC02-06CH11357
Recently, RadiaBeam has designed and built a robust thermionic RF gun with optimized electromagnetic per-formance, improved thermal engineering, and a robust cathode mounting technique. This gun allows to improve the performance of existing and future light sources, industrial accelerators, and electron beam driven te-rahertz sources. Unlike conventional electrically or side-coupled RF guns, this new gun operates in ’-mode with the help of magnetic coupling holes. Such a design al-lows operation at longer pulses and has negligible dipole and quadrupole components. The gun prototype was built, then installed and tested at the Advanced Photon Source (APS) injector. This paper presents the results of high power and beam tests of this RF gun, and operation-al experience at APS to this moment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT036

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Received ※ 31 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022

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THPOTK014

100 keV Electron Source Design for the New 3 GeV Synchrotron Facility in Thailand

cathode, electron, focusing, simulation

2800

N. Juntong, S. Bootiew, T. Chanwattana, Ch. Dhammatong, S. Jummunt, K. Kittimanapun, W. Phacheerak
SLRI, Nakhon Ratchasima, Thailand
K. Manasatitpong
Synchrotron Light Research Institute (SLRI), Muang District, Thailand

The Synchrotron Light Research Institute (SLRI) is developing a new synchrotron light source with an electron beam energy of 3 GeV. The DC thermionic electron gun was chosen because it is simple and less cost. The design process is well known. The operation is more stable compared to the RF gun. The cathode Y-646B was considered because it had already been used at the old synchrotron machine and the possibility of sharing the stock outweighs other disadvantages. Moreover, it is used in many synchrotron facilities, so it is easy to find references. The present of the focusing electrode was discussed. The focusing electrode will increase the complexity of the gun, but it is necessary to get a high-quality beam from the gun. The designed electron gun can produce 1.1 A beams current with the normalized emittance of 0.910 Pi·mm·mrad, which satisfied the requirement of the linac injector. The design and study results will be discussed in this report.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK014

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Received ※ 20 May 2022 — Accepted ※ 14 June 2022 — Issue date ※ 29 June 2022

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THPOTK015

Solid-State Pulsed Power Supply for a 100 keV Electron Source of the New Synchrotron Facility in Thailand

electron, high-voltage, power-supply, simulation

2803

W. Phacheerak, S. Bootiew, T. Chanwattana, Ch. Dhammatong, N. Juntong, K. Kittimanapun
SLRI, Nakhon Ratchasima, Thailand
K. Manasatitpong
Synchrotron Light Research Institute (SLRI), Muang District, Thailand

The new synchrotron light source project in Thailand will utilize a thermionic DC electron gun. The maximum operation of the gun is 100 keV, which requires a pulsed power supply of 100kV. The present synchrotron machine uses a conventional design of the gun power supply. To improve the high voltage pulsed quality, the solid-state design of the gun power supply is utilized. The output pulse width can be adjusted easily and the droop is less compared to the conventional design. The designed output of 100 kV amplitude with 5 µs pulsed width can be achieved with this design. It also produces a less droop of 1.8%. The design process and results will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK015

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022

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THPOTK041

Development of Programmable Bipolar Multi kHz Kicker Drivers for Long Pulse Superconducting Electron Linacs

kicker, FEL, electron, laser

2862

J.L. Teichgräber, W. Decking, J. Kahl, F. Obier
DESY, Hamburg, Germany

Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany Superconducting cavities allow for long rf-pulses, which enable the acceleration of thousands of electron bunches within one rf-pulse. Due to transient effects, e.g. coupler kicks, eddy currents or wakefields, bunch properties like the beam trajectory can change along the pulse train. To compensate for this, kicker systems based on high-current operational amplifiers have been developed for the free electron lasers European XFEL and FLASH at DESY in Hamburg. Here, we present the layout of the kicker system, the setup of the pulse electronics, and operational results with beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK041

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Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 19 June 2022

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THPOTK054

Proposal of a VHEE Linac for FLASH Radiotherapy

linac, electron, cavity, simulation

2903

L. Giuliano, F. Bosco, M. Carillo, D. De Arcangelis, A. De Gregorio, L. Ficcadenti, D. Francescone, G. Franciosini, M. Migliorati, A. Mostacci, L. Palumbo, V. Patera, A. Sarti
Sapienza University of Rome, Rome, Italy
D. Alesini, A. Gallo, A. Vannozzi
INFN/LNF, Frascati, Italy
M. Behtouei, L. Faillace, B. Spataro
LNF-INFN, Frascati, Italy
M.G. Bisogni, F. Di Martino, J.H. Pensavalle
INFN-Pisa, Pisa, Italy
G.A.P. Cirrone, G. Cuttone, G. Torrisi
INFN/LNS, Catania, Italy
V. Favaudon, A. Patriarca
Institut Curie - Centre de Protonthérapie d’Orsay, Orsay, France
S. Heinrich
Institut Curie, Centre de Recherche, Orsay, France

Translation of electron FLASH radiotherapy in clinical practice requires the use of high energy accelerators to treat deep tumours and Very High Electron Energy (VHEE) could represent a valid technique to achieve this goal. In this sce- nario, a VHEE FLASH linac is under study at the University La Sapienza of Rome (Italy) in collaboration with the Italian Institute for Nuclear Research (INFN) and the Curie Insti- tute (France). Here we present the preliminary results of a compact C-band system aiming to reach an high accelerating gradient and an high pulse current necessary to deliver high dose per pulse and ultra-high dose rate required for FLASH effect. We propose a system composed of a low energy high current injector linac followed by a modular section of high accelerating gradient structures. CST code is used to define the required LINAC’s RF parameters and beam dynamics simulations are performed using T-Step, ASTRA and GPT tracking codes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK054

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Received ※ 17 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022

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THPOTK059

Laser System for SuperKEKB RF Gun in Phase III Commissioning

laser, electron, MMI, injection

2914

R. Zhang, M. Yoshida, X. Zhou
KEK, Ibaraki, Japan
H.K. Kumano, N. Toyotomi
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

In order to generate high quality electron beam with high charge in Phase III commissioning of SuperKEKB, some improvements have been done in Ytterbium doped fiber and Neodymium doped YAG (Nd:YAG) hybrid laser system. Spatial reshaping part for the 4th harmonic laser beam at 266 nm has been adopted to realize low emittance electron beam. In addition, for achieving continuous and stable laser operation, position feedback system has also been used to improve the pointing stability of laser beam. In 2021 commissioning of SuperKEKB, stable 2 nC electron beam is generated for high energy ring (HER) injection. Meanwhile, we achieved the best emittance results at B-sector of linac injector and BT line for comparable low injection background and higher injection efficiency. With the aim of generating higher charge electron beam with good quality in the following commissioning, a perspective towards the next step update for current laser system is also introduced.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK059

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 04 July 2022

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THPOMS013

Electron Gun System Design for FLASH Radiotherapy

electron, cathode, power-supply, radiation

2970

H.-S. Lee, J.H. Jang, K.Y. Jang, J.C. Koo, H.S. Shin, D.H. Yu
VITZRONEXTECH, Ansan-si, Gyeonggi-do, Republic of Korea
D.H. An, S.H. Choi, K.U. Kang, G.B. Kim, J.H. Kim
KIRAMS, Seoul, Republic of Korea
Y.G. Son
PAL, Pohang, Republic of Korea

An electron gun is a device that emits electron beams used in an electron accelerator, an electron beam welder, an x-ray generator, etc. This device can be broadly divided into three components: a cathode, a grid, and an anode. A medical electron gun, which is a sub-system of an electron accelerator for FLASH radiotherapy, requires a high current. The electron gun was designed to obtain a peak current up to 15A using EIMAC Y824 cathode. We would like to introduce the structure of the electron gun and the required power supply system. In this paper, we will describe the optimization process of the electron gun structure design, the Marx-type power supply providing 200 kV pulse voltage, and the grid pulse power supply ranging from 1ns to 1.5 ’s.
Electron gun design, Accelerator, Radiotherapy, High Current

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS013

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 28 June 2022 — Issue date ※ 10 July 2022

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THPOMS036

HERACLES: A High Average Current Electron Beamline for Lifetime Testing of Novel Photocathodes

cathode, electron, vacuum, laser

3041

M.B. Andorf, J. Bae, A.C. Bartnik, I.V. Bazarov, J.M. Maxson
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
L. Cultrera
BNL, Upton, New York, USA

Funding: DOE-NP DE-SC0021425 NSF PHY 1549132
We report on the building and commissioning of a high current beamline dedicated to testing novel photocathodes for high current and spin-polarized electron applications. The main features of the beamline are a 200 keV DC electron gun and a beam dump capable of handling 75 kW of beam power. In this report, a Cs3Sb photocathode is used to demonstrate the facilities high current capabilities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS036

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 30 June 2022

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FRIXSP1

Low-Emittance Compact RF Electron Gun with a Gridded Thermionic Cathode

electron, emittance, cathode, cavity

3124

T. Asaka
JASRI/SPring-8, Hyogo-ken, Japan

A new type of rf electron gun has been developed to generate a stable electron beam with a low-emittance of ~1 um.rad, that can be injected into SX-FEL and DLSR, without using a large UV laser system nor an ultra-high voltage pulsers. This electron gun consists of a 50 kV pulsed gun equipped with a commercially available thermionic cathode with grid and a 238-MHz acceleration cavity driven by a 42 kW solid-state amplifier. The system is simple, stable, robust, and of easy-maintenance. To obtain a "grid-transparent" condition, the cathode voltage and the control grid voltage are optimized not to distort the electric field near the grid. To avoid the emittance growth due to the space charge effect, the gun and a special magnetic lens are embedded in the 238-MHz cavity at the shortest distance, and the beam energy is immediately accelerated to 500 kV. The first model of this electron gun has been operated as the 1 GeV injector of the NewSUBARU storage ring. The same electron gun will also be used in the injector linac of the 3 GeV light source under construction in Japan. The talk is expected to include the concept, overall design and the achieved performance.

Slides FRIXSP1 [2.893 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXSP1

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Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 23 June 2022

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FRPLYGD2

Access to Effective Cancer Care in Low- Middle Income Countries Requires Sophisticated Linear Accelerator Based Radiotherapy

linac, radiation, survey, electron

3147

M. Dosanjh
CERN, Meyrin, Switzerland

There are substantial and growing gaps in cancer care for millions of people in Low- Middle- Income countries (LMICs) and for geographically remote settings in High-income countries (HICs), often indigenous populations. Assessing the cancer care shortfall led to understanding the essential gap, that of a radiation therapy machine that can reliably and effectively provide the appropriate first-rate cancer treatments within the challenging environments. More than 10,000 electron linear accelerators (linacs) are currently used worldwide to treat patients. However only 10% of patients in low-income and 40% in middle-income countries who need radiotherapy have access to it. The idea to address the need for a novel medical linac for challenging environments has led to the creation of the STELLA project (Smart Technology to Extend Lives with Linear Accelerators) project. STELLA is multidisciplinary international collaborative effort to design and develop an affordable and robust yet technically sophisticated linear accelerator-based radiation therapy treatment (RTT) in LMICs. Here we describe Project STELLA.

Slides FRPLYGD2 [6.047 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRPLYGD2

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 29 June 2022

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