Keyword: laser
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MOPLXGD2 Progress Towards Demonstration of a Plasma-Based FEL plasma, FEL, electron, wakefield 6
 
  • E. Chiadroni
    LNF-INFN, Frascati, Italy
 
  Plasma-based technology promises a revolution in the field of particle accelerators by pushing beams to gigaelectronvolt energies within centimeter distances. Several experiments are ongoing world-wide towards demonstration of a plasma based FEL enabling the realization of ultra-compact facilities for user applications like Free-Electron Lasers (FEL). The progress towards a plasma based FEL user facility is here reported, with particular focus on the recent results about the first experimental evidence of FEL lasing by a compact (3 cm) particle beam-driven plasma accelerator at the SPARC_LAB test facility. The status and prospects are discussed.  
slides icon Slides MOPLXGD2 [17.683 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPLXGD2  
About • Received ※ 12 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022
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MOIYGD1 Progress in Developing an Accelerator on a Chip electron, acceleration, focusing, photon 16
 
  • R.J. England
    SLAC, Menlo Park, California, USA
  • R.L. Byer
    Stanford University, Stanford, California, USA
  • P. Hommelhoff
    University of Erlangen-Nuremberg, Erlangen, Germany
 
  Acceleration of particles in photonic structures fabricated using semiconductor manufacturing techniques and driven by ultrafast solid state lasers is a new and promising approach to developing future generations of compact particle accelerators. Substantial progress has been made in this area in recent years, fueled by a growing international collaboration of universities, national laboratories, and companies. Performance of these micro-accelerator devices is ultimately limited by laser-induced material breakdown limits, which can be substantially higher for optically driven dielectrics than for radio-frequency metallic cavities traditionally used in modern particle accelerators, allowing for 1 to 2 order of magnitude increase in achievable accelerating fields. The lasers required for this approach are commercially available with moderate (microJoule class) pulse energies and repetition rates in the MHz regime. We summarize progress to date and outline potential near-term applications and offshoot technologies.  
slides icon Slides MOIYGD1 [13.851 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOIYGD1  
About • Received ※ 03 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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MOPOPT013 Comparative Study of Broadband Room Temperature THz Detectors for High and Intermediate Frequency Response detector, experiment, electron, photon 257
 
  • R. Yadav, S. Preu
    IMP, TU Darmstadt, Darmstadt, Germany
  • A. Penirschke
    THM, Friedberg, Germany
 
  Funding: Scholarship from Hesse ministry of science and culture (HMWK), Germany.
Room temperature terahertz (THz) detectors based on Field effect transistors (FETs) and Zero-bias Schottky diodes (SD) are prominent members for the temporal-spatial characterization of pulses down to the picosecond scale generated at particle accelerators. Comparative study of in house developed THz detectors both at higher and intermediate frequency (IF) is carried out using table top THz systems and commercially available sources. In this paper, we present high frequency and intermediate frequency (IF) response of Gallium Arsenide (GaAs) FET and Zero-bias Schottky diode THz detectors. The IF results obtained are helpful for understanding and designing of optimized IF circuit with broader bandwidth.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT013  
About • Received ※ 19 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022
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MOPOPT016 Update of the Bunch Arrival Time Monitor at ELBE electron, controls, feedback, pick-up 260
 
  • M. Kuntzsch, A. Maalberg, A. Schwarz, K. Zenker
    HZDR, Dresden, Germany
  • M.K. Czwalinna, J. Kral
    DESY, Hamburg, Germany
 
  The bunch arrival time monitor (BAM) at the radiation source ELBE has been upgraded twofold. In order to achieve a higher precision a new frontend has been designed, based on a development by DESY, that uses state of the art 50 GHz electro-optical modulators (EOMs). The frontend allows for thermal control of critical components and monitoring of system parameters. The modulated EOM signals and monitoring data are distributed to a new readout electronic. The new MicroTCA-based receiveris based on a dedicated FMC card developed at DESY that is installed on an FMC25 carrier board. The arrival time is calculated on a FPGA with low latency and can be used for machine diagnostic. The code has been adapted to enable the processing of a data stream of the continuous train of electron bunches, allowing for the implementation of a cw beam based feedback in a next step. The contribution will describe the BAM setup as well as the performance measured at the ELBE accelerator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT016  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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MOPOPT017 Terahertz Sampling Rates with Photonic Time-Stretch for Electron Beam Diagnostics photon, software, electron, data-acquisition 263
 
  • O. Manzhura, E. Bründermann, M. Caselle, S.A. Chilingaryan, T. Dritschler, S. Funkner, A. Kopmann, A.-S. Müller, M.J. Nasse, G. Niehues, M.M. Patil, J.L. Steinmann
    KIT, Karlsruhe, Germany
  • S. Bielawski, E. Roussel, C. Szwaj
    PhLAM/CERCLA, Villeneuve d’Ascq Cedex, France
  • S. Bielawski, E. Roussel, C. Szwaj
    PhLAM/CERLA, Villeneuve d’Ascq, France
 
  Funding: Supported by the Helmholtz Program-Oriented Funding (PoF), research program Matter and Technologies (Detector Technology and System), ANR-DFG ULTRASYNC funding program, CEMPI LABEX and Wavetech CPER.
To understand the underlying complex beam diagnostic often large numbers of single-shot measurements must be acquired continuously over a long time with extremely high temporal resolution. Photonic time-stretch is a measurement method that is able to overcome speed limitations of con- ventional digitizers and enable continuous ultra-fast single- shot terahertz spectroscopy with refresh rates of trillions of consecutive frames. In this contribution, a novel ultra- fast data sampling system based on photonic time-stretch is presented and the performance is discussed. THERESA (TeraHErtz REadout SAmpling) is a data acquisition system based on the recent ZYNQ-RFSoC family. THERESA has been developed with an analog bandwidth up to 20 GHz and a sampling rate up to 90 GS/s. When combined with the photonic time-stretch setup, the system will be able to sample a THz signal with an unprecedented frame rate of 8 TS/s. Continuous acquisition for long observation times will open up new possibilities in the detection of rare events in accelerator physics.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT017  
About • Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022
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MOPOPT020 Longitudinal Phase Space Diagnostics with Corrugated Structure at the European XFEL electron, diagnostics, FEL, optics 275
 
  • S. Tomin, W. Decking, N. Golubeva, A.I. Novokshonov, T. Wohlenberg, I. Zagorodnov
    DESY, Hamburg, Germany
 
  Characterization of the longitudinal phase space (LPS) of the electron beam after the FEL process is important for its study and tuning. At the European XFEL, a single plate corrugated structure was installed after the SASE2 undulator to measure the LPS of the electron beam. The beam passing near the plate’s corrugations creates wakefields, which induce a correlation between time and the transverse distribution of the beam. The longitudinal phase space of the beam is then analyzed on a scintillating screen monitor placed in the dispersion section. In this paper, we present the result of commissioning the corrugated structure and the first LPS measurement.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT020  
About • Received ※ 12 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
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MOPOPT024 Measuring the Coherent Synchrotron Radiation Far Field with Electro-Optical Techniques detector, radiation, synchrotron, synchrotron-radiation 292
 
  • C. Widmann, M. Brosi, E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, M.-D. Noll, M.M. Patil, M. Reißig, J.L. Steinmann
    KIT, Karlsruhe, Germany
  • M. Brosi
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  Funding: M. M. P. acknowledges the support by the DFG-funded Doctoral School KSETA. C. W. achnowledges funding by BMBF contract number 05K19VKD.
For measuring the temporal profile of the coherent synchrotron radiation (CSR) a setup based on electro-optical spectral decoding (EOSD) will be installed as part of the sensor network at the KIT storage ring KARA (Karlsruhe Research Accelerator). The EOSD technique allows a single-shot, phase sensitive measurement of the complete spectrum of the CSR far field radiation at each turn. Therefore, the dynamics of the bunch evolution, e.g. the microbunching, can be observed in detail. Especially, in synchronized combination with the already established near-field EOSD, this method could provide deeper insights in the interplay of bunch profile and CSR generation for each individual electron bunch. For a successful implementation of the EOSD single shot setup, measurements with electro-optical sampling (EOS) are performed. With EOS the THz pulse shape is scanned over several turns by shifting the delay of laser and THz pulse. In this contribution different steps towards the installation of the EOSD far field setup are summarized.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT024  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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MOPOPT025 Development of an Electro-Optical Longitudinal Bunch Profile Monitor at KARA Towards a Beam Diagnostics Tool for FCC-ee electron, operation, collider, polarization 296
 
  • M. Reißig, M. Brosi, E. Bründermann, S. Funkner, B. Härer, A.-S. Müller, G. Niehues, M.M. Patil, R. Ruprecht, C. Widmann
    KIT, Karlsruhe, Germany
 
  Funding: The Future Circular Collider Innovation Study (FCCIS) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 951754. M. R. and M. M. P. acknowledge the support by the Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology". C. W. achnowledges funding by BMBF contract number 05K19VKD.
The Karlsruhe Research Accelerator (KARA) at KIT features an electro-optical (EO) near-field diagnostics setup to conduct turn-by-turn longitudinal bunch profile measurements in the storage ring using electro-optical spectral decoding (EOSD). Within the Future Circular Collider Innovation Study (FCCIS) an EO monitor using the same technique is being conceived to measure the longitudinal profile and center-of-charge of the bunches in the future electron-positron collider FCC-ee. This contribution provides an overview of the EO near-field diagnostics at KARA and discusses the development and its challenges towards an effective beam diagnostics concept for the FCC-ee.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT025  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022
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MOPOPT029 Longitudinal Phase Space Benchmarking for PITZ Bunch Compressor simulation, booster, FEL, experiment 310
 
  • A. Lueangaramwong, Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, X.-K. Li, O. Lishilin, D. Melkumyan, H.J. Qian, G. Shu, F. Stephan, G. Vashchenko, T. Weilbach
    DESY Zeuthen, Zeuthen, Germany
  • N. Chaisueb
    Chiang Mai University, Chiang Mai, Thailand
 
  The longitudinal phase space characteristics of space-charge dominated electron beams are keys to achieving bunch compression for the accelerator-based THz source at the Photo Injector Test facility at DESY in Zeuthen (PITZ). Such a THz source is proposed as a prototype for an accelerator-based THz source for pump-probe experiments at the European XFEL. A start-to-end simulation has suggested the settings of the phase of booster linear accelerator manipulating longitudinal beam characteristics to optimize the performance of the THz FEL. Although beam diagnostics after compression at PITZ are limited, the longitudinal beam characteristics as a function of the booster phase have been measured and compared with the corresponding simulations. The benchmark involves measurements of longitudinal phase space distribution for bunch charges up to 2 nC. The measurement technique assigned uses 50-um slits to achieve higher momentum and time resolution (1.8 keV/c and 0.5 ps, respectively).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT029  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022
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MOPOPT031 Renovation of the SR Beam Profile Monitors with Novel Polycrystalline Diamond Mirrors at the SuperKEKB Accelerator extraction, optics, radiation, synchrotron 313
 
  • G. Mitsuka, H. Ikeda, T.M. Mitsuhashi
    KEK, Ibaraki, Japan
 
  SR beam profile monitors are fundamental to perform the stable beam operation of SuperKEKB. To suppress thermal deformation of SR extraction mirrors–a long-standing issue in SR monitors–, we developed platinum coated diamond mirrors in 2019. The diamond mirrors are made with optical-quality polycrystal-diamond-substrate with extremely large thermal conductivity, and have a size of 20 mm (W) x 30 mm (H) x 2 mm (D). Surface flatness better than λ/5 was observed in an optical testing with a laser interferometer. The diamond mirrors have been installed in HER and LER in 2020 summer and 2021 summer, respectively. Through irradiation for an year at the beam current greater than 800 mA, no significant deformation of the diamond mirrors has been observed. In this talk, we will discuss the design, construction, and optical testing of the polycrystal diamond mirrors. Also beam measurements performed using an interferometer, a coronagraph, a streak camera, and a fast gate camera will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT031  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 02 July 2022
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MOPOPT042 Recent AWAKE Diagnostics Development and Operational Results electron, proton, plasma, experiment 343
 
  • E. Senes, S. Burger, M. Krupa, T. Lefèvre, S. Mazzoni, E. Poimenidou, A. Topaloudis, M. Wendt, G. Zevi Della Porta
    CERN, Meyrin, Switzerland
  • P. Burrows, C. Pakuza
    JAI, Oxford, United Kingdom
  • P. Burrows, C. Pakuza
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • D.A. Cooke
    UCL, London, United Kingdom
  • J. Wolfenden
    The University of Liverpool, Liverpool, United Kingdom
  • J. Wolfenden
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  The Advanced Wakefield Experiment (AWAKE) at CERN investigates the Plasma-Wakefield acceleration of electrons driven by a relativistic proton bunch. After successfully demonstrating the acceleration process in the AWAKE Run 1, the experiment has now started the Run 2. The AWAKE Run 2 consists of several experimental periods that aim to demonstrate the feasibility of the AWAKE concept beyond the acceleration experiment, showing its feasibility as accelerator for particle physics application. As part of these developments, a dramatic effort in improving the AWAKE instrumentation is sustained. This contribution reports on the current developments of the instrumentation pool upgrade, including the digital camera system for transverse beam profile measurement, beam halo measurement and the spectrometer upgrade studies. The studies on the development of high-frequency beam position monitors are also described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT042  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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MOPOPT054 A Modified Nomarski Interferometer to Study Supersonic Gas Jet Density Profiles vacuum, experiment, optics, diagnostics 385
 
  • C. Swain, O. Apsimon, A. Salehilashkajani, C.P. Welsch, J. Wolfenden, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • Ö. Apsimon, A. Salehilashkajani, C. Swain, C.P. Welsch, J. Wolfenden, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
 
  Funding: This work is supported by the AWAKE-UK phase II project grant No. ST/T001941/1, the STFC Cockcroft core grant No. ST/G008248/1 and the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1.
Gas jet-based non-invasive beam profile monitors, such as those developed for the high luminosity Large Hadron Collider (HL-LHC) upgrade, require accurate, high resolution methods to characterise the supersonic gas jet density profile. This paper proposes a modified Nomarski interferometer to non-invasively study the behaviour of these jets, with nozzle diameters of 1 mm or less in diameter. It discusses the initial design and results, alongside plans for future improvements. Developing systems such as this which can image on such a small scale allows for improved monitoring of supersonic gas jets used in several areas of accelerator science, thus allowing for improvements in the accuracy of experiments they are utilised in.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT054  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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MOPOPT057 Updates in Efforts to Data Science Enabled MeV Ultrafast Electron Diffraction System electron, network, gun, 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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MOPOTK001 The Influence of Solenoid Field on Off-Axis Travelling Beam in AREAL Accelerator solenoid, alignment, simulation, experiment 422
 
  • H. Davtyan
    CANDLE, Yerevan, Armenia
  • G.A. Amatuni, A.A. Asoyan, A. Grigoryan, M.G. Yazichyan
    CANDLE SRI, Yerevan, Armenia
  • A. Grigoryan
    YSU, Yerevan, Armenia
 
  A wide range of experiments are being held at AREAL accelerator in the fields of materials science and life sci-ence by generating ultra-short 5 MeV electron beams. Beam parameter formation and stability preservation during the experiments are one of the key tasks of stable operation of the accelerator. Laser spot displacement on the photocathode could be one of the beam parameter distortion sources, which causes off-axis bunch travel also through the solenoid. The influences of laser spot horizontal displacement and the solenoid horizontal misalignment on the beam position at the experiment location are investigated separately via computer simulations. Using a laser spot mover and solenoid movers, an experiment has been carried out to compare simulation results with experiment.
*davtyan@asls.candle.am
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK001  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
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MOPOTK045 Generation of High Emittance Ratios in High Charge Electron Beams at FACET-II emittance, quadrupole, experiment, cathode 560
 
  • O. Camacho
    UCLA, Los Angeles, USA
  • A. Halavanau, R. Robles
    SLAC, Menlo Park, California, USA
 
  Funding: DE-SC0009914
Experiments foreseen at FACET-II, including dielectric plasma wakefield acceleration and linear collider tests, call for electron beams with highly asymmetric transverse emittances - so called "flat beams". A canonical recipe for the generation of such beams is injecting a magnetized beam at a waist into an appropriately tuned skewed quadrupole triplet channel. However, due to the intense non-linear space-charge forces that dominate nC bunches, this method presents difficulties in maintaining the flatness. We proceed with generalized round-to-flat-beam (RTFB) transformation, which takes into account the non-negligible divergence of the beam at the channel entrance, using a quartet of skewed quadrupoles. Our analytical results are further optimized in ELEGANT and GPT simulation programs and applied to the case of the FACET-II beamline. Non-ideal cathode spot distributions obtained from recent FACET-II experiments are used for accurate numerical modeling. Tolerances to quadrupole strengths and alignment errors are also considered, with an eye towards developing hardware specifications.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK045  
About • Received ※ 03 June 2022 — Revised ※ 24 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 09 July 2022
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MOPOTK052 CEBAF Injector Model for KL Beam Conditions simulation, experiment, gun, 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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MOPOTK066 Damping-Ring-Free Injector Design for Linear Colliders emittance, cavity, electron, SRF 614
 
  • T. Xu, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • S.Y. Kim, P. Piot, J.G. Power
    ANL, Lemont, Illinois, USA
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
 
  Funding: This work was supported by the US DOE contracts # DE-SC0018656 and # DE-SC0018234 (U.S.-Japan Science & Technology Cooperation Program in HEP) with NIU and No.DE-AC02-06CH11357 with ANL.
The current designs of future electron-positron linear colliders incorporate large and complex damping rings to produce asymmetric beams for beamstrahlung mitigation at the interaction point. This paper presents the design of an damping-ring-free electron injector capable of delivering flat electron beams with phase-space partition comparable to the electron-beam parameters produced downstream of the damping ring in the proposed international linear collider (ILC) design. The performance of the proposed configuration, its sensitivity to jitter along with its impact on spin-polarization is discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK066  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 13 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, gun, linac 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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MOPOMS008 Diagnosis of Transverse Emittance in Laser-Driven Ion Beam emittance, target, proton, simulation 637
 
  • T. Miyatake, I. Takemoto, Y. Watanabe
    Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Kasuga-Shi, Japan
  • T.-H. Dinh, M. Kando, S. Kojima, K. Kondo, K. Kondo, M. Nishikino, M. Nishiuchi, H. Sakaki
    National Institutes for Quantum Science and Technology, Kyoto, Japan
 
  Funding: This work was supported by JST-MIRAI R&D Program No. JPMJMI17A1. This work was supported by JSPS KAKENHI Grant Number JP21J22132.
Ion beam produced in laser-driven ion acceleration by ultra-intense lasers has characteristics of high peak cur-rent and low emittance. These characteristics become an advantage to operate the request for the beam applica-tion. Therefore, we study how to control the parameters with the laser-plasma interaction. Here, we used 2D Particle-in-Cell code to simulate the laser-driven ion acceleration and investigated the results in terms of transverse emittance, beam current, and brightness. The laser spot size and target thickness were changed in the simulation. And, these qualitative results show that interaction target thickness is a major factor in controlling beam characteristics.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS008  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 18 June 2022
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MOPOMS014 Commissioning of a High-Gradient X-Band RF Gun Powered by Short RF Pulses from a Wakefield Accelerator gun, electron, 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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MOPOMS015 Temporal and Spatial Characterization of Ultrafast Terahertz Near-Fields for Particle Acceleration acceleration, electron, simulation, radiation 656
 
  • A.E. Gabriel, M.C. Hoffmann, E.A. Nanni, M.A.K. Othman
    SLAC, Menlo Park, California, USA
 
  Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515.
We have measured the THz near-field in order to inform the design of improved THz-frequency accelerating structures. THz-frequency accelerating structures could provide the accelerating gradients needed for next generation particle accelerators with compact, GV/m-scale devices. One of the most promising THz generation techniques for accelerator applications is optical rectification in lithium niobate using the tilted pulse front method. However, accelerator applications are limited by significant losses during transport of THz radiation from the generating nonlinear crystal to the acceleration structure. In addition, the spectral properties of high-field THz sources make it difficult to couple THz radiation into accelerating structures. A better understanding of the THz near-field source properties is necessary for the optimization of THz transport and coupling. We have developed a technique for detailed measurement of the THz near-fields and used it to reconstruct the full temporal 3D THz near-field close to the LN emission face. Analysis of the results from this measurement will inform designs of novel structures for use in THz particle acceleration.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS015  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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MOPOMS016 Application of Nanostructures and Metamaterials in Accelerator Physics electron, acceleration, wakefield, plasma 659
 
  • J. Resta-López
    ICMUV, Paterna, Spain
  • Ö. Apsimon, C. Bonțoiu, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • A. Bonatto
    Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
  • B. Galante
    CERN, Meyrin, Switzerland
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G.X. Xia
    UMAN, Manchester, United Kingdom
 
  Funding: This work is supported by the Generalitat Valenciana under Grant agreement No. CIDEGENT/2019/058.
Carbon-based nanostructures and metamaterials offer extraordinary mechanical and opto-electrical properties, which make them suitable for applications in diverse fields, including, for example, bioscience, energy technology and quantum computing. In the latest years, important R&D efforts have been made to investigate the potential use of graphene and carbon-nanotube (CNT) based structures to manipulate and accelerate particle beams. In the same way, the special interaction of graphene and CNTs with charged particles and electromagnetic radiation might open interesting possibilities for the design of compact coherent radiation sources, and novel beam diagnostics techniques as well. This paper gives an overview of novel concepts based on nanostructures and metamaterials with potential application in the field of accelerator physics. Several examples are shown and future prospects discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS016  
About • Received ※ 08 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 13 June 2022  
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MOPOMS023 Start-to-End Beam-Dynamics Simulations of a Compact C-Band Electron Beam Source for High Spectral Brilliance Applications electron, simulation, FEL, photon 687
 
  • L. Faillace, M. Behtouei, B. Spataro, C. Vaccarezza
    LNF-INFN, Frascati, Italy
  • R.B. Agustsson, I.I. Gadjev, S.V. Kutsaev, A.Y. Murokh
    RadiaBeam, Santa Monica, California, USA
  • F. Bosco, M. Carillo, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • D.L. Bruhwiler
    RadiaSoft LLC, Boulder, Colorado, USA
  • O. Camacho, A. Fukasawa, N. Majernik, J.B. Rosenzweig, O. Williams
    UCLA, Los Angeles, USA
  • A. Giribono
    INFN/LNF, Frascati, Italy
  • S.G. Tantawi
    SLAC, Menlo Park, California, USA
 
  Funding: This work is partially supported by DARPA under the Contract No. HR001120C0072, by DOE Contract DE-SC0009914, DOE Contract DE-SC0020409, and by the National Science Foundation Grant No. PHY-1549132.
Proposals for new linear accelerator-based facilities are flourishing world-wide with the aim of high spectral brilliance radiation sources. Most of these accelerators are based on electron beams, with a variety of applications in industry, research and medicine such as colliders, free-electron lasers, wake-field accelerators, coherent THz and inverse Compton scattering X/’ sources as well as high-resolution diagnostics tools in biomedical science. In order to obtain high-quality electron beams in a small footprint, we present the optimization design of a C-band linear accelerator machine. Driven by a novel compact C-band hybrid photoinjector, it will yield ultra-short electron bunches of few 100’s pC directly from injection with ultra-low emittance, fraction of mm-mrad, and a few hundred fs length simultaneously, therefore satisfying full 6D emittance compensation. The normal-conducting linacs are based on a novel high-efficiency design with gradients up to 50 MV/m. The beam maximum energy can be easily adjusted in the mid-GeV’s range. In this paper, we discuss the start-to-end beam-dynamics simulations in details.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS023  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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MOPOMS032 Compact-Two-Octave-Spanning Perpendicular Kicker of MeV Electrons Based on a Cubic Magnet Dipole Array electron, dipole, radiation, kicker 706
 
  • T. Rohwer, R. Bazrafshan, F.X. Kärtner, N.H. Matlis
    Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
  • R. Bazrafshan
    University of Hamburg, Hamburg, Germany
  • F.X. Kärtner
    The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
  • F.X. Kärtner
    CFEL, Hamburg, Germany
  • P. Vagin
    DESY, Hamburg, Germany
 
  Funding: This work has been supported by the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) through the Synergy Grant AXSIS (609920).
New compact particle acceleration structures, including but not limited to plasma, THz and direct laser driven accelerators, have in common that they cover a wide energy range of potential final energies and often show a large energy spread. Moreover, they may initially have a rather large emittance. To analyze the energy range of a single shot and/or to deflect the beam to safely dump the electrons away from an end-station requires an electron kicker covering a large energy range. Here, we present a magnetic dipole structure based on a 2D Halbach array. For the current experimental test accelerator in AXSIS, an electron beam in the energy range from 4 to 20 MeV is deflected by 90 degree and energetically dispersed. In direct contrast to a simple magnetic dipole, an array of cubic magnet blocks with tailored magnetization directions allows a focusing of the beam for both longitudinal and transverse directions at 90 degree bend. A generic algorithm optimizes the magnetic field array to the predefined deflection angle and divergence. The modular array structure, in combination with the algorithm enables a simple exchange of magnets to adapt for different beam parameters.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS032  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022
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MOPOMS033 Emittance Measurements of Nanoblade-Enhanced High Field Cathode cathode, electron, simulation, emittance 709
 
  • G.E. Lawler, N. Majernik, J.I. Mann, N.E. Montanez, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • V.S. Yu
    RadiaBeam, Santa Monica, California, USA
 
  Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132.
High brightness cathodes are increasingly a focus for accelerator applications ranging from free electron lasers to ultrafast electron diffraction. There is further an increasing interest in fabrication and control of cathode surface to better control the emission characteristics and improve beam brightness. One method which we can consider is based on well-known silicon nanofabrication techniques which we use to create patterned cathode surfaces. The sharp edges produced lead to field emission increases and high brightness emission. We have demonstrated that a beam can be successfully extracted with a low emittance and we have reconstructed a portion of the energy spectrum. Due to the simplicity of extended geometries in nanofabrication our beam uniquely possesses a high aspect ratio in its transverse cross section. We can begin to consider modifications for emittance exchange beamlines and having shown the patterning principle is sound we can consider additional patterns such as hollow beams. Future work will continue to characterize the produced beam and the addition of fabrication steps to remove one of the blades in the double blade geometry in order to more accurately characterize the emission.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS033  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
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MOPOMS036 Simulations of Laser Field Emission from Nanostructures with Image Charge Trapping and Band Structure Transitions electron, simulation, vacuum, photon 717
 
  • B. Wang, G.E. Lawler, J.I. Mann, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • T. Arias, J.K. Nangoi
    Cornell University, Ithaca, New York, USA
  • S.S. Karkare
    Arizona State University, Tempe, USA
 
  Funding: National Science Foundation Grant No. PHY-1549132
Laser-induced field emission from nanostructures as a means to create high brightness electron beams has been a continually growing topic of study. Experiments using nanoblade emitters have achieved peak fields upwards of 40 GV/m, begging further investigation in this extreme regime. A recent paper has provided analytical reductions of the common semi-infinite Jellium system for pulsed incident lasers. We utilize these results as well as similar previous results to further understand the physics underlying electron rescattering-type emissions. We progress in numerically evaluating the analytical solution to attempt to more efficiently generate spectra for this system. Additionally, we use the full 1-D time-dependent Schrödinger equation with a Hartree potential and a dispersion-relation transition from material to vacuum to study the same system. We determine what importance the inclusion of the material band structure may have on emissions using this computationally challenging approach.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS036  
About • Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 01 July 2022
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TUOXSP3 Evaluation of Geometrical Precision and Surface Roughness Quality for the Additively Manufactured Radio Frequency Quadrupole Prototype rfq, operation, radio-frequency, radio-frequency-quadrupole 787
 
  • T. Torims, D. Krogere, G. Pikurs, A. Ratkus
    Riga Technical University, Riga, Latvia
  • A. Cherif, M. Vretenar
    CERN, Meyrin, Switzerland
  • N. Delerue
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • M. Foppa Pedretti, M. Pozzi
    Rösler Italiana s.r.l., Concorezzo, Italy
  • S. Gruber, E. Lopez
    Fraunhofer IWS, Dresden, Germany
  • T. Otto
    TalTech, Tallinn, Estonia
  • M. Thielmann, P. Wagenblast
    TRUMPF, Ditzingen, Germany
  • M. Vedani
    POLIMI, Milano, Italy
 
  A multidisciplinary collaboration within the I.FAST project teamed-up to develop additive manufacturing (AM) technology solutions for accelerators. The first prototype of an AM pure-copper radio frequency quadrupole (RFQ) has been produced, corresponding to 1/4 of a 4-vane RFQ*. It was optimised for production with state-of-the-art laser powder bed fusion technology. Geometrical precision and roughness of the critical surfaces were measured. Alt-hough the obtained values were beyond standard RFQ specifications, these first results are promising and con-firmed the feasibility of AM manufactured complex cop-per accelerator cavities. Therefore, further post-processing trials have been conducted with the sample RFQ to im-prove surface roughness. Algorithms for the AM techno-logical processes have also been improved, allowing for higher geometrical precision. This resulted in the design of a full 4-vane RFQ prototype. At the time of the paper submission the full-size RFQ is being manufactured and will undergo through the stringent surface quality meas-urements. This paper is discussing novel technological developments, is providing an evaluation of the obtained surface roughness and geometrical precision as well as outlining the potential post-processing scenarios along with future tests plans.
* Torims T, et al. First Proof-of-Concept Prototype of an Additive Manufactured Radio Frequency Quadrupole. Instruments. 2021; 5(4):35. https://doi.org/10.3390/instruments5040035
 
slides icon Slides TUOXSP3 [10.031 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOXSP3  
About • Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 10 July 2022
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TUPOST009 Online Correction of Laser Focal Position Using FPGA-Based ML Models network, FPGA, controls, electron 857
 
  • J.A. Einstein-Curtis, S.J. Coleman, N.M. Cook, J.P. Edelen
    RadiaSoft LLC, Boulder, Colorado, USA
  • S.K. Barber, C.E. Berger, J. van Tilborg
    LBNL, Berkeley, California, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Numbers DE-SC 00259037 and DE-AC02-05CH11231.
High repetition-rate, ultrafast laser systems play a critical role in a host of modern scientific and industrial applications. We present a prototype diagnostic and correction scheme for controlling and determining laser focal position at 10 s of Hz rate by utilizing fast wavefront sensor measurements from multiple positions to train a focal position predictor. This predictor is used to determine corrections for actuators along the beamline to provide the desired correction to the focal position on millisecond timescales. Our initial proof-of-principle demonstrations leverage pre-compiled data and pre-trained networks operating ex-situ from the laser system. We then discuss the application of a high-level synthesis framework for generating a low-level hardware description of ML-based correction algorithms on FPGA hardware coupled directly to the beamline. Lastly, we consider the use of remote computing resources, such as the Sirepo scientific framework* , to actively update these correction schemes and deploy models to a production environment.
* M.S. Rakitin et al., "Sirepo: an open-source cloud-based software interface for X-ray source and optics simulations", Journal of Synchrotron Radiation 25, 1877-1892 (Nov 2018).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST009  
About • Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
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TUPOST046 Machine Learning Applied for the Calibration of the Hard X-Ray Single-Shot Spectrometer at the European XFEL FEL, photon, controls, operation 965
 
  • C. Grech, M.W. Guetg
    DESY, Hamburg, Germany
  • G. Geloni
    EuXFEL, Schenefeld, Germany
 
  Single-crystal monochromators are used in free electron lasers for hard x-ray self-seeding, selecting a very narrow spectral range of the original SASE signal for further amplification. When rotating the crystal around the roll and pitch axes, one can exploit several symmetric and asymmetric reflections as established by Bragg’s law. This work describes the implementation of a machine learning classifier to identify the crystal indices corresponding to a given reflection, and eventually calculate the difference between the photon energy as measured by a single-shot spectrometer and the actual one. The image processing techniques to extract the properties of the crystal reflection are described, as well as how this information is used to calibrate two spectrometer parameters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST046  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 09 July 2022
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TUPOPT005 Status of the Superconducting Soft X-Ray Free-Electron Laser User Facility FLASH undulator, FEL, experiment, operation 1006
 
  • M. Vogt, C. Gerth, K. Honkavaara, M. Kuhlmann, J. Rönsch-Schulenburg, L. Schaper, S. Schreiber, R. Treusch, J. Zemella
    DESY, Hamburg, Germany
 
  The XUV and soft X-ray free-electron laser FLASH at DESY is capable of operating two undulator beamlines simultaneously with up to several thousand bunches per second. It is driven by a normal conducting RF photo-cathode gun and a superconducting L-band linac. FLASH is currently undergoing a substantial refurbishment and upgrade program (FLASH2020+). The first 9-months installation shutdown started in November 2021. Here we report on the operation in 2021 and present main upgrades during the ongoing shutdown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT005  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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TUPOPT010 Virtual Commissioning of the European XFEL for Advanced User Experiments at Photon Energies Beyond 25 keV Using Low-Emittance Electron Beams FEL, electron, photon, free-electron-laser 1018
 
  • Y. Chen, F. Brinker, W. Decking, M. Scholz, L. Winkelmann, Z.H. Zhu
    DESY, Hamburg, Germany
 
  Funding: The authors acknowledge support from Deutsches Elektronen-Synchrotron DESY (Hamburg, Germany), a member of the Helmholtz Association HGF and European XFEL GmbH (Schenefeld, Germany).
Growing interests in ultra-hard X-rays are pushing forward the frontier of commissioning the European X-ray Free-Electron Laser (XFEL) for routine operation towards the sub-ångström regime, where a photon energy of 25 keV (0.5 ångström) is desired. Such X-rays allow for larger penetration depths and enable the investigation of materials in highly absorbing environments. Delivering the requested X-rays to user experiments is of crucial importance for the XFEL development. Unique capabilities of the European XFEL are formed by combining a high energy linac and the long variable-gap undulator systems for generating intense X-rays at 25 keV and pushing the limit even further to 30 keV. However, the FEL performance relies on achievable electron bunch qualities. Low-emittance electron bunch production, and the associated start-to-end modelling of beam physics thus becomes a prerequisite to dig into the XFEL potentials. Here, we present the obtained results from a virtual commissioning of the XFEL for the user experiments at 25 keV and beyond, including the optimized electron bunch qualities at variable accelerating cathode gradients and lasing studies under different conditions.
*Appl. Sci. 11(22), 10768 (2021)
**Phys. Rev. Accel. Beams 23, 044201(2020)
***NIM A 995, 11 165111 (2021)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT010  
About • Received ※ 19 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 08 July 2022
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TUPOPT013 Twin Delayed Deep Deterministic Policy Gradient for Free-electron Laser Online Optimization FEL, electron, network, undulator 1025
 
  • M. Cai, C. Feng, L. Tu, Z.T. Zhao, Z.H. Zhu
    SINAP, Shanghai, People’s Republic of China
  • C. Feng, K.Q. Zhang, Z.T. Zhao
    SSRF, Shanghai, People’s Republic of China
  • D. Gu
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
 
  X-ray free-electron lasers (FEL) have contributed to many frontier applications of nanoscale science which benefit from its extraordinary properties. During FEL commissioning, the beam status optimization especially orbit correction is particularly significant for FEL amplification. For example, the deviation between beam orbit and the magnetic center of undulator can affect the interaction between the electron beam and the FEL pulse. Usually, FEL commissioning requires a lot of effort for multi-dimensional parameters optimization in a time-varying system. Therefore, advanced algorithms are needed to facilitate the commissioning procedure. In this paper, we propose an online method to optimize the FEL power and transverse coherence by using a twin delayed deep deterministic policy gradient (TD3) algorithm. The algorithm exhibits more stable learning convergence and improves learning performance because the overestimation bias of policy gradient methods is suppressed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT013  
About • Received ※ 17 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022
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TUPOPT018 Fermi 2.0 Future Upgrade Strategy FEL, electron, simulation, bunching 1041
 
  • L. Giannessi, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, M. Coreno, M.B. Danailov, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, W.M. Fawley, M. Ferianis, G. Gaio, F. Gelmetti, G. Kurdi, M. Lonza, M. Malvestuto, M. Manfredda, C. Masciovecchio, I. Nikolov, G. Penco, K.C. Prince, E. Principi, P. Rebernik Ribič, C. Scafuri, N. Shafqat, P. Sigalotti, A. Simoncig, F. Sottocorona, S. Spampinati, C. Spezzani, L. Sturari, M. Trovò, M. Veronese, R. Visintini, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • M. Coreno
    CNR-ISM, Trieste, Italy
  • G. Penn
    LBNL, Berkeley, California, USA
  • G. Perosa
    Università degli Studi di Trieste, Trieste, Italy
  • T. Tanaka
    RIKEN SPring-8 Center, Hyogo, Japan
 
  FERMI is studying a series of developments to keep the facility in a world-leading position on the base of the requests coming from the user community, the Scientific Advisory Council and the Machine Advisory Committee. The ultimate goal of the development plan consists in doubling the photon energy range and reducing the pulse duration below the characteristic lifetime of the atomic core levels located in the energy range of the source. One of the most promising approaches is the echo-enabled harmonic generation (EEHG) scheme, relying on two external lasers to precisely control the spectro-temporal properties of the FEL pulse. The implementation of EEHG in the double-stage harmonic cascade presently in use on FEL-2, would allow harmonics as high as 120 enabling to generate coherent pulses down to 2 nm starting from UV lasers. An upgrade of FERMI aimed at reaching the oxygen K-edge requires a profound modification of the FEL configurations and of the main components of the machine, including the linac and the undulator lines. The main aspects of the upgrade strategy will be discussed in this presentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT018  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022
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TUPOPT019 FERMI FEL-1 Upgrade to EEHG FEL, electron, free-electron-laser, simulation 1044
 
  • C. Spezzani, E. Allaria, L. Badano, D. Castronovo, P. Cinquegrana, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, M. Ferianis, G. Gaio, F. Gelmetti, L. Giannessi, G. Kurdi, M. Lonza, C. Masciovecchio, I. Nikolov, G. Penco, P. Rebernik Ribič, C. Scafuri, N. Shafqat, P. Sigalotti, F. Sottocorona, S. Spampinati, L. Sturari, M. Trovò, M. Veronese, R. Visintini
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • G. Perosa
    Università degli Studi di Trieste, Trieste, Italy
 
  The Fermi free-electron laser (FEL) facility is operating since 2010 providing the user community with ultrashort pulses in the VUV- XUV range. Using the High Gain Harmonic Generation (HGHG) setup, nearly transform-limited pulses with gigawatt peak power are made available. Furthermore, several multicolor and coherent control schemes are possible and highly required from the user community. To meet the request of extending the spectral range over the whole water window, an upgrade strategy of the FERMI facility has recently initiated. During the first phase of the upgrade, the single cascade FEL-1 will be adapted to operate either in Echo Enabled Harmonic Generation (EEHG) or in HGHG. Required modifications can be achieved with limited impact on FERMI operations and will improve FEL-1’s spectral range, spectral quality and flexibility. The second phase includes modification of the FEL-2 setup and will benefit from the experience gained with phase 1. The two phases will proceed in parallel to the linac upgrade aiming at extending the beam energy to 1.8 GeV. We report here details on the upgrade of the FEL-1 foreseen to provide light to users in the new configuration by spring 2023.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT019  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 29 June 2022
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TUPOPT023 Undulator Tapering Studies of an Echo-Enabled Harmonic Generation Based Free-Electron Laser undulator, FEL, electron, radiation 1047
 
  • F. Pannek, W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • S. Ackermann, E. Ferrari, L. Schaper
    DESY, Hamburg, Germany
 
  The free-electron laser (FEL) user facility FLASH at DESY is currently undergoing an upgrade which involves the transformation of one of its beamlines to allow for external seeding via so-called Echo-Enabled Harmonic Generation (EEHG). With this seeding technique it will be possible to provide stable, longitudinal coherent and intense radiation in the XUV and soft X-ray regime at high repetition rate. To ensure an efficient FEL amplification process, sustainable energy exchange between the electrons and the electromagnetic field in the undulator is mandatory. Adequate adjustment of the undulator strength along the beamline allows to compensate for electron energy loss and to preserve the resonance condition. The impact of this undulator tapering on the temporal and spectral characteristics on the EEHG FEL radiation at 4 nm is investigated by means of numerical simulations performed with the FEL code GENESIS 1.3, version 4. Different tapering methods are examined and it is shown that specific tapering of the undulator strength allows to exceed the FEL saturation power while maintaining a clear temporal and spectral shape of the FEL pulse.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT023  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022
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TUPOPT032 Simulating Beam Transport with Permanent Magnet Chicane for THz Fel electron, FEL, undulator, GUI 1077
 
  • A.C. Fisher, M.P. Lenz, P. Musumeci, A. Ody, Y. Park
    UCLA, Los Angeles, USA
  • R.B. Agustsson, T.J. Hodgetts, A.Y. Murokh
    RadiaBeam, Santa Monica, California, USA
 
  Funding: This work was supported by NSF grant PHY-1734215 and DOE grant No. DE-SC0009914 and DE-SC0021190. The undulator construction has been carried out under SBIR/STTR DE-SC0017102 and DE-SC0018559.
Free electron lasers are an attractive option for high average and peak power radiation in the THz gap, a region of the electromagnetic spectrum where radiation sources are scarce, as the required beam and undulator parameters are readily achievable with current technology. However, slippage effects require the FEL to be driven with relatively long and low current electron bunches, limiting amplification gain and output power. Previous work demonstrated that a waveguide could be used to match the radiation and e-beam velocities in a meter-long strongly-tapered helical undulator, resulting in 10\% energy extraction from an ultrashort 200 pC, 5.5 MeV electron beam. We present simulations for a follow-up experiment targeting higher frequencies with improvements to the e-beam transport including a permanent magnet chicane for strong beam compression. FEL simulations show >20\% extraction efficiency from a 125 pC, 7.4 MeV electron beam at 0.32 THz.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT032  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
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TUPOPT034 Modelling of X-Ray Volume Excitation of the XLO Gain Medium Using Flash plasma, simulation, electron, target 1081
 
  • P. Manwani, N. Majernik, B. Naranjo, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • E.C. Galtier, A. Halavanau, C. Pellegrini
    SLAC, Menlo Park, California, USA
 
  Funding: This work was performed with the support of the US Department of Energy under Contract No. DE-AC02-76SF00515 and DESC0009914.
Plasma dynamics and crater formation of laser excited volumes in solids is a complex process due to thermalization, shockwave formation, varying absorption mechanisms, and a wide range of relevant physics timescales. The properties and interaction of such laser-matter systems can be modeled using an equation of state and opacity based multi-temperature treatment of plasma using a radiation hydrodynamics code. Here, we use FLASH, an adaptive mesh radiation-hydrodynamics code, to simulate the plasma expansion following after the initial energy deposition and thermalization of the column, to benchmark the results of experiments undertaken at UCLA on optical laser ablation. These computational results help develop a quantitative understanding of the material excitation process and enable the optimization of the gain medium delivery system for the x-ray laser oscillator project *.
* Halavanau, Aliaksei, et al. "Population Inversion X-Ray Laser Oscillator." Proceedings of the National Academy of Sciences, vol. 117, no. 27, 2020, pp. 15511-15516.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT034  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 24 June 2022
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TUPOPT035 Introduction of Westwood Linear Accelerator Test Facility in University of California Los Angeles gun, 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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TUPOPT036 Two and Multiple Bunches with the LCLS Copper Linac timing, controls, undulator, electron 1089
 
  • F.-J. Decker, W.S. Colocho, A. Halavanau, A.A. Lutman, J.P. MacArthur, G. Marcus, R.A. Margraf, J.C. Sheppard, J.J. Turner, S. Vetter
    SLAC, Menlo Park, California, USA
 
  Two, four, and even eight bunches were accelerated through the copper linac. Two and four bunches were delivered successfully to photon experiments in both the hard (HXR) and soft (SXR) LCLS x-ray lines. In this paper we will concentrate on the more challenging issues, such as: the BPM deconvolution for both bunches, RF kicks at longer separations, tuning challenges, bridging the communications gap between the photon and electron side, the lower bunch charges for the eight bunch case, and rapid timing scans over several ns. We will describe some of the developed solutions and plans for the rest.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT036  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
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TUPOPT038 FAST-GREENS: A High Efficiency Free Electron Laser Driven by Superconducting RF Accelerator undulator, electron, experiment, radiation 1094
 
  • P. Musumeci, P.E. Denham, A.C. Fisher, Y. Park
    UCLA, Los Angeles, California, USA
  • R.B. Agustsson, T.J. Hodgetts, A.Y. Murokh, M. Ruelas
    RadiaBeam, Santa Monica, California, USA
  • L. Amoudry
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • D.R. Broemmelsiek, S. Nagaitsev, J. Ruan, J.K. Santucci, G. Stancari, A. Valishev
    Fermilab, Batavia, Illinois, USA
  • D.L. Bruhwiler, J.P. Edelen, C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  • A.H. Lumpkin, A. Zholents
    ANL, Lemont, Illinois, USA
 
  Funding: This work is supported by DOE grants DE-SC0017102, DE-SC0018559 and DE-SC0009914
In this paper we’ll describe the FAST-GREENS experimental program where a 4 m-long strongly tapered helical undulator with a seeded prebuncher is used in the high gain TESSA regime to convert a significant fraction (up to 10 %) of energy from the 240 MeV electron beam from the FAST linac to coherent 515 nm radiation. We’ll also discuss the longer term plans for the setup where by embedding the undulator in an optical cavity matched with the high repetition rate from the superconducting accelerator (3,9 MHz), a very high average power laser source can be obtained. Eventually, the laser pulses can be redirected onto the relativistic electrons to generate by inverse compton scattering a very high flux of circularly polarized gamma rays for polarized positron production.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT038  
About • Received ※ 09 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 02 July 2022
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TUPOPT039 Characterization of Diamond with Buried Boron-Doped Layer Developed for Q-Switching an X-Ray Optical Cavity cavity, FEL, lattice, ECR 1097
 
  • R.A. Margraf, A. Halavanau, Z. Huang, J. Krzywiński, J.P. MacArthur, G. Marcus, M.L. Ng, A.R. Robert, R. Robles, T. Sato, D. Zhu
    SLAC, Menlo Park, California, USA
  • Z. Huang, F. Ke, R. Robles, Y. Zhong
    Stanford University, Stanford, California, USA
  • S.-K. Mo, Y. Zhong
    LBNL, Berkeley, California, USA
  • P. Pradhan
    ANL, Lemont, Illinois, USA
  • A.R. Robert
    MAX IV Laboratory, Lund University, Lund, Sweden
  • M.D. Ynsa
    UAM, Madrid, Spain
 
  Funding: This work was supported by the Department of Energy, Laboratory Directed Research and Development program at SLAC National Accelerator Laboratory, under contract DE-AC02-76SF00515.
X-ray Free-Electron Laser Oscillators (XFELOs) and X-ray Regenerative Amplifier FELs (XRAFELs) are currently in development to improve longitudinal coherence and spectral brightness of XFELs. These schemes lase an electron beam in an undulator within an optical cavity to produce X-rays. X-rays circulate in the cavity and interact with fresh electron bunches to seed the FEL process over multiple passes, producing progressively brighter and more spectrally pure X-rays. Typically, the optical cavities used are composed of Bragg-reflecting mirrors to provide high reflectivity and spectral filtering. This high reflectivity necessitates special techniques to out-couple X-rays from the cavity to deliver them to users. One method involves "Q-switching" the cavity by actively modifying the reflectivity of one Bragg-reflecting crystal. To control the crystal lattice constant and thus reflectivity, we use an infrared laser to heat a buried boron layer in a diamond crystal. Here, we build on earlier work in Krzywinski et al.* and present the current status of our Q-switching diamond, including implantation with 9 MeV boron ions, annealing, characterization and early tests.
*Krzywinski et al., "Q-switching of X-Ray Optical Cavities by using Boron Doped Buried Layer under a Surface of a Diamond Crystal," Proceedings of FEL2019, Hamburg, Germany, TUP033, 2019.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT039  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 08 July 2022
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TUPOPT044 High-Power Attosecond Pulses via Cascaded Amplification electron, FEM, experiment, ISOL 1101
 
  • P.L. Franz, Z.H. Guo, S. Li, R. Robles
    Stanford University, Stanford, California, USA
  • D.K. Bohler, D.B. Cesar, X. Cheng, J.P. Cryan, T.D.C. Driver, J.P. Duris, A. Kamalov, S. Li, A. Marinelli, R. Obaid, R. Robles, N.S. Sudar, A.L. Wang, Z. Zhang
    SLAC, Menlo Park, California, USA
 
  Funding: This work was supported by US Department of Energy Contracts No. DE-AC02-76SF00.
The timescale for electron motion in molecular systems is on the order of hundreds of attoseconds, and thus the time-resolved study of electronic dynamics requires a source of sub-femtosecond x-ray pulses. Here we report the experimental generation of sub-femtosecond duration soft x-ray free electron laser (XFEL) pulses with hundreds of microjoules of energy using fresh-slice amplification in two cascaded stages at the Linac Coherent Light Source. In the first stage, an enhanced self-amplified spontaneous emission (ESASE) pulse is generated using laser-shaping of the electron beam at the photocathode*. The electron bunch is then delayed relative to the pulse by a magnetic chicane, allowing the radiation to slip onto a fresh slice of the bunch, which amplifies the ESASE pulse in the second cascade stage. Angular streaking** characterizes the experimental pulse durations as sub-femtosecond at ~465 eV in the experiment.
* Zhang, Z. et al. New J. Phys. 22 (2020)
** Li, S. et al. Optics Express 26.4 (2018): 4531-4547.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT044  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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TUPOPT047 Progress Report on Population Inversion X-Ray Laser Oscillator at LCLS cavity, target, experiment, FEL 1107
 
  • A. Halavanau, R. Alonso-Mori, A. Aquila, U. Bergmann, F.-J. Decker, F. Fuller, M. Liang, A.A. Lutman, R.A. Margraf, R.H. Paul, C. Pellegrini
    SLAC, Menlo Park, California, USA
  • R. Ash, N.B. Welke
    UW-Madison/PD, Madison, Wisconsin, USA
  • A.I. Benediktovitch
    DESY, Hamburg, Germany
  • S.C. Krusic
    JSI, Ljubljana, Slovenia
  • N. Majernik, P. Manwani, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • R. Robles
    Stanford University, Stanford, California, USA
  • N. Rohringer
    Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
 
  We report the progress in the design and construction of a population inversion x-ray laser oscillator (XLO) using LCLS as an x-ray laser pump, being developed by a SLAC, CFEL, University of Hamburg (Germany), University of Wisconsin, Josef Stefan Institute (Slovenia) and UCLA collaboration. In this proceeding, we will present the latest XLO design and numerical simulations substantiated by our first experimental results. In our next experimental step XLO will be tested on the Coherent X-ray Imaging (CXI) end-station at LCLS as a two pass Regenerative Amplifier operating at the Copper Kα1 photon energy of 8048 eV. When built, XLO will generate fully coherent transform limited pulses with about 50 meV FWHM bandwidth. We expect the XLO will pave the way for new user experiments, e.g. in inelastic x-ray scattering, parametric down conversion, quantum science, x-ray interferometry, and external hard x-ray XFEL seeding.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT047  
About • Received ※ 12 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022
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TUPOPT052 Proposal for Non-Destructive Electron Beam Diagnostic with Laser-Compton Backscattering at the S-Dalinac photon, electron, scattering, linac 1121
 
  • M.G. Meier, M. Arnold, J. Enders, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
 
  Funding: Work supported in part by the state of Hesse within the research cluster ELEMENTS (project ID 500/10.006) and the LOEWE research cluster Nuclear Photonics and by DFG through GRK 2128 "Accelence" and Inst163/308-1 FUGG.
To recover a large fraction of energy from the accelerator process in an energy-recovery linac, experiments, secondary-beam production, and beam diagnostics must be non-destructive and/or, hence, feature a low interaction probability with the very intense electron-beam. Laser-Compton backscattering can provide a quasi-monochromatic highly polarized X-ray to γ-ray beam without strongly affecting the electron beam due to the small recoil and the small Compton cross-section. Highest energies of the scattered photons are obtained for photon-scattering angles of \ang{180}, i. e., backscattering. A project at TU Darmstadt foresees to synchronize a highly repetitive high-power laser with the Superconducting DArmstadt electron LINear ACcelerator S\hbox{-}DALINAC, capable of running in energy recovery mode * to realize a laser-Compton backscattering source with photon beam energy up to §I{180}{\kilo\electronvolt}. The source will be first used as a diagnostic tool for determining and monitoring key electron-parameters, in particular energy and the energy spread at the S\hbox{-}DALINAC operation. Results are foreseen to be used for optimizing the design of laser-Compton backscattering sources at energy-recovery linacs.
*M. Arnold et al., Phys. Rev. Accel. Beams 23, 020101(2020)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT052  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 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 feedback, LLRF, gun, 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOPT068 Transverse and Longitudinal Modulation of Photoinjection Pulses at FLUTE electron, injection, cathode, controls 1174
 
  • M. Nabinger, A.-S. Müller, M.J. Nasse, C. Sax, J. Schäfer, C. Widmann, C. Xu
    KIT, Eggenstein-Leopoldshafen, Germany
 
  Funding: Supported by the Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology" (KSETA).
To generate the electrons to be accelerated, a photoinjection laser is used at the linac-based test facility FLUTE (Ferninfrarot Linac- Und Test Experiment) at the Karlsruhe Institute of Technology (KIT). The properties of the laser pulse, such as intensity, laser spot size or temporal profile, are the first parameters to influence the characteristics of the electron bunches. In order to control the initial parameters of the electrons in the most flexible way possible, the laser optics at FLUTE are therefore supplemented by additional setups that allow transverse and longitudinal laser pulse shaping by using so-called Spatial Light Modulators (SLMs). In the future, the control of the SLMs will be integrated into a Machine Learning (ML) supported feedback system for the optimization of the electron bunch properties. In this contribution the first test experiments and results on laser pulse shaping at FLUTE on the way to this project are presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT068  
About • Received ※ 07 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 22 June 2022  
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TUPOTK023 Study on Commercial Diodes as Thermometers at Low Temperature for Temperature Mapping System of Nb3sn Superconducting Radiofrequency Cavities experiment, cavity, SRF, controls 1252
 
  • R. Wanison, K. Umemori, T. Yamada
    KEK, Ibaraki, Japan
  • K. Takahashi
    Sokendai, Ibaraki, Japan
  • R. Wanison
    Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai, Thailand
 
  Nb3Sn Superconducting radiofrequency (SRF) cavities has been researched and developed at Center for Applied Superconducting Accelerator (CASA), KEK. One of effec-tive tools for research on the performance of SRF cavities is a temperature mapping (T-map) system for detecting small increases in temperature. It is a thermometer array positioned precisely on an outer surface of cavity wall. Thermometer should cover at least from the range of typi-cal operating temperature of 4 K to the transition tempera-ture of 18 K, for the Nb3Sn SRF cavities. Therefore, car-bon resistor can not be used as a cheap thermometer due to low sensitivity at this temperature range. In this pro-ceeding, we report the results of the test for various com-mercially available diodes as a thermometer for T-map system. The sensitivity, stability and the repeatability are measured, cooled by a GM cryocooler.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK023  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 07 July 2022
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TUPOMS011 Progress Towards EEHG Seeding at the DELTA Storage Ring electron, undulator, vacuum, storage-ring 1420
 
  • B. Büsing, A. Held, H. Kaiser, S. Khan, C. Mai, A. Radha Krishnan
    DELTA, Dortmund, Germany
 
  Funding: Funded by BMBF (05K16PEB, 05K19PEB), FZ Jülich, and by the federal state NRW.
Seeding of free-electron lasers (FELs) with external laser pulses triggers the microbunching process such that the spectrotemporal properties of coherently emitted FEL radiation are under better control compared to self-amplified spontaneous emission. High-gain harmonic generation (HGHG) based on the interaction of electrons with a single laser pulse is routinely applied at a few FELs, and echo-enabled harmonic generation (EEHG) with a twofold laser-electron interaction has been demonstrated. Both schemes can be adopted in storage rings for the coherent emission of ultrashort radiation pulses. Coherent harmonic generation (CHG) is the counterpart to HGHG without FEL gain. It has been employed at several storage rings and presently provides ultrashort pulses in the vacuum ultraviolet regime at the 1.5-GeV electron storage ring DELTA operated by the TU Dortmund University. EEHG, which allows to reach higher harmonics of the seed wavelength, has not yet been implemented at any storage ring but is pursued at DELTA as an upgrade plan. The paper presents the layout of the envisaged EEHG facility, and it reviews simulation studies and the technical progress towards EEHG seeding at DELTA.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS011  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 29 June 2022
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TUPOMS012 Investigation of Spectro-Temporal Properties of CHG Radiation at DELTA electron, radiation, storage-ring, bunching 1423
 
  • A. Radha Krishnan, B. Büsing, A. Held, H. Kaiser, S. Khan, C. Mai, Z. Usfoor, V. Vijayan
    DELTA, Dortmund, Germany
 
  Funding: Funded by DFG (INST 212/236-1 FUGG), BMBF (05K16PEA, 05K19PEB), and by the federal state NRW.
At the synchrotron light source DELTA operated by the TU Dortmund University, the short-pulse facility employs the seeding scheme coherent harmonic generation (CHG) and provides ultrashort pulses in the vacuum ultraviolet and terahertz regime. Here, the interaction of laser pulses with the stored electron bunches results in a modulation of the longitudinal electron density which gives rise to coherent emission at harmonics of the laser wavelength. The spectral and temporal properties of such coherent short pulses can be manipulated by the seed laser properties and chicane strength. CHG spectra at several harmonics of the 800 nm seed laser were recorded using an image-intensified CCD (iCCD) camera and a newly installed XUV spectrometer. Numerical simulations to calculate the spectral phase properties of the seed laser from the observed spectra were carried out.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS012  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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TUPOMS024 Sensitivity of EEHG Simulations to Dynamic Beam Parameters electron, FEL, simulation, radiation 1463
 
  • D. Samoilenko, W. Hillert, F. Pannek
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • S. Ackermann, E. Ferrari, N.S. Mirian, P. Niknejadi, G. Paraskaki, L. Schaper
    DESY, Hamburg, Germany
  • F. Curbis, M.A. Pop, S. Werin
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  Currently, the Free electron laser user facility FLASH at DESY is undergoing a significant upgrade involving the complete transformation of one of its beamlines to allow external seeding. With the Echo-Enabled Harmonic Generation (EEHG) seeding method, we aim for the generation of fully coherent XUV and soft X-ray pulses at wavelengths down to 4 nm. The generated FEL radiation is sensitive to various electron beam properties, e.g., its energy profile imprinted either deliberately or by collective effects such as Coherent Synchrotron Radiation (CSR). In dedicated particle tracking simulations, one usually makes certain assumptions concerning the beam properties and the collective effects to simplify implementation and analysis. Here, we estimate the influence of some of the common assumptions made in EEHG simulations on the properties of the output FEL radiation, using the example of FLASH and its proposed seeding beamline. We conclude that the inherent properties of the FLASH1 beam, namely the negatively chirped energy profile, has dominant effect on the spectral intensity profile of the radiators output compare to that of the CSR induced chirp.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS024  
About • Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 29 June 2022
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TUPOMS043 High Power Tests of a New 4-Rod RFQ with Focus on its Mechanical Vibrations simulation, rfq, experiment, operation 1523
 
  • S.R. Wagner, D. Koser, K. Kümpel, H. Podlech
    IAP, Frankfurt am Main, Germany
  • K.B. Bahrke-Rein
    TU Darmstadt, Darmstadt, Germany
  • M. Basten
    GSI, Darmstadt, Germany
  • M. Basten
    HIM, Mainz, Germany
  • H. Podlech
    HFHF, Frankfurt am Main, Germany
 
  Because of strong mechanical vibrations of the electrodes and its sensitivity to changes of thermal load, the operational stability of the existing 4-rod RFQ at the High Charge State Injector (HLI) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, could not be ensured for all planned operating states. To resolve this issue and ensure stable injection into the HLI, a new RFQ-prototype, optimized in terms of vibration suppression and cooling efficiency, was designed at the Institute of Applied Physics (IAP) of Goethe University Frankfurt. To test the performance of this prototype and demonstrate the operational stability in terms of mechanical vibration as well as thermal load, high power tests with more than 25’kW/m were performed at GSI. After initial conditioning, detailed vibrational measurements during high power RF operation using a laser Doppler vibrometer were performed, which were then compared to previously conducted simulations using ANSYS. Ultimately, the ability for stable operation up to high power levels with an efficient vibration suppression and moderate heating have clearly been demonstrated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS043  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022
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WEIXSP1 Towards High-Repetition Rate Petawatt Laser Experiments with Cryogenic Jets Using a Mechanical Chopper System target, proton, experiment, plasma 1594
 
  • M. Rehwald, S. Assenbaum, C. Bernert, U. Schramm, K. Zeil
    HZDR, Dresden, Germany
  • C.B. Curry, M. Gauthier, S.H. Glenzer, C. Schoenwaelder, F. Treffert
    SLAC, Menlo Park, California, USA
  • S. Göde
    EuXFEL, Schenefeld, Germany
 
  Laser-plasma based ion accelerators require suitable high-repetition rate target systems that enable systematic studies at controlled plasma conditions and application-relevant particle flux. Self-refreshing, micrometer-sized cryogenic jets have proven to be an ideal target platform. Yet, operation of such systems in the harsh environmental conditions of high power laser induced plasma experiments have turned out to be challenging. Here we report on recent experiments deploying a cryogenic hydrogen jet as a source of pure proton beams generated with the PW-class ultrashort pulse laser DRACO. Damage to the jet target system during application of full energy laser shots was prevented by implementation of a mechanical chopper system interrupting the direct line of sight between the laser plasma interaction zone and the jet source.  
slides icon Slides WEIXSP1 [4.896 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIXSP1  
About • Received ※ 16 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
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WEOXSP2 All Optical Chartacterization of a Dual Grating Accelerator Structure electron, controls, acceleration, simulation 1602
 
  • S.A. Crisp, P. Musumeci, A. Ody
    UCLA, Los Angeles, USA
 
  Funding: ACHIP grant from the Gordon and Betty Moore Foundation (GBMF4744) U.S. Department of Energy grant DE-AC02-76SF00515 National Science Foundation Graduate Research Fellowship Program Grant DGE1650604.
We present progress and an experimental plan for multi-MeV relativistic energy gain in a dielectric laser-driven accelerator (DLA). Using a 780 nm, 100 fs pulse-front-tilted laser, we achieve interaction with 6 MeV electrons over a 4 mm long structure with 800 nm period. To compensate for resonant defocusing effects, the laser pulse is imprinted with a phase mask, applied by a Spatial Light Modulator, which uses alternating phase focusing (APF) to achieve stable beam transport. The DLA is mechanically mounted with a variable sized gap (600-1200 nm) in order to maximize transmission while maintaining high gradient within the channel. The combination of high interaction length and use of APF confines and accelerates the electrons by up to 3.5 MeV.
 
slides icon Slides WEOXSP2 [1.603 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXSP2  
About • Received ※ 08 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 29 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEOZGD1 Design of an LPA-Based First-Stage Injector for a Synchrotron Light Source electron, plasma, beam-loading, simulation 1639
 
  • X.Y. Shi, H.S. Xu
    IHEP, Beijing, People’s Republic of China
 
  Study of plasma-based acceleration has been a frontier of accelerator community for decades. The beam performance obtained from a laser-plasma based accelerator (LPA) becomes higher and higher. Nowadays, a combination of LPAs and the conventional RF accelerators is a trend. One of the interesting directions to go is to replace a LINAC by an LPA as the first-stage injector of a synchrotron light source. In this paper, we present a physical design of a 500 MeV LPA-based first-stage injector for a synchrotron light source.  
slides icon Slides WEOZGD1 [8.971 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZGD1  
About • Received ※ 15 June 2022 — Revised ※ 22 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 04 July 2022
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WEINGD1 Industry and Accelerator Science, Technology, and Engineering - the Need to Integrate (Building Bridges) electron, radiation, network, MMI 1644
 
  • R. Geometrante
    KYMA, Trieste, Italy
  • S. Biedron
    Element Aero, Chicago, USA
  • E. Braidotti
    CAEN ELS srl, Trieste, Italy
  • J.M.A. Priem
    VDL ETG, Eindhoven, The Netherlands
  • J.C. Rugsancharoenphol
    FTI, Bangkok, Thailand
  • S.L. Sheehy
    The University of Melbourne, Melbourne, Victoria, Australia
  • M. Vretenar
    CERN, Meyrin, Switzerland
 
  Abstract  
slides icon Slides WEINGD1 [36.079 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEINGD1  
About • Received ※ 05 July 2022 — Accepted ※ 04 July 2022 — Issue date ※ 05 July 2022  
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WEPOST010 Controlling e+/e Circular Collider Bunch Intensity by Laser Compton Scattering electron, collider, scattering, photon 1695
 
  • F. Zimmermann
    CERN, Meyrin, Switzerland
  • T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
 
  Funding: This project receives funding from the European Union’s H2020 Framework Programme under grant agreement no. 951754 (FCCIS).
In the future circular electron-positron collider "FCC-ee", the intensity of colliding bunches must be tightly controlled, with a maximum charge imbalance between collision partner bunches of less than 3-5%. Laser Compton back scattering could be used to adjust and fine-tune the bunch intensity. We discuss a possible implementation and suitable laser parameters.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST010  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 03 July 2022
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WEPOST021 Theoretical Study of Laser Energy Absorption Towards Energetic Proton and Electron Sources target, electron, proton, simulation 1737
 
  • I.M. Vladisavlevici, E. d’Humières
    CELIA, Talence, France
  • D. Vizman
    West University of Timisoara, Timisoara, Romania
 
  Funding: This work was supported by Romanian National Authority for Scientific Research PN 75/2018, Agence Nationale de la Recherche project ANR-17-CE30-0026-Pinnacle, WUT - JINR collaboration project 05-6-1119-2014/2023 (2/2019; 86/2020; 103/2021) and Erasmus+ Student grant (2018/2019; 2019/2020; 2020/2021).
Our main goal is to describe and model the energy transfer from laser to particles, from the transparent to less transparent regime of laser-plasma interaction in the ultra-high intensity regime, and using the results obtained to optimize laser ion acceleration. We investigate the case of an ultra high intensity (1022 W/cm2) ultra short (20 fs) laser pulse interacting with a near-critical density plasma made of electrons and protons of density 5 nc (where nc = 1.1·1021 cm-3 is the critical density for a laser wavelength of 1 µm). Through 2D particle-in-cell (PIC) simulations, we study the optimal target thickness for the maximum conversion efficiency of the laser energy to particles. Theoretical modelling of the predominant laser-plasma interaction mechanisms predicts the particle energy and conversion efficiency optimization. Our studies led to an optimization of the target thickness for maximizing electron and proton acceleration.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST021  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 08 July 2022
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WEPOST029 First Start-to-End Simulations of the 6 GeV Laser-Plasma Injector at DESY plasma, emittance, injection, electron 1757
 
  • S.A. Antipov, I.V. Agapov, R. Brinkmann, A. Ferran Pousa, M.A. Jebramcik, A. Martinez de la Ossa, M. Thévenet
    DESY, Hamburg, Germany
 
  DESY is studying the feasibility of a 6 GeV laser-plasma injector for top-up operation of its future flagship synchrotron light source PETRA IV. A potential design of such an injector involves a single plasma stage, a beamline for beam capture and phase space manipulation, and a X-band rf energy compressor. Numerical tracking with realistic beam distributions shows that an energy variation below 0.1%, rms and a transverse emittance about 1 nm-rad, rms can be achieved under realistic timing, energy, and pointing jitters. PETRA IV injection efficiency studies performed with a conservative 5% beta-beating indicate negligible beam losses for the simulated beams during top-up. Provided the necessary progress on high-power lasers and plasma cells, the laser plasma injector could become a competitive alternative to the conventional injector chain.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST029  
About • Received ※ 02 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022
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WEPOST030 Multitask Optimization of Laser-Plasma Accelerators Using Simulation Codes with Different Fidelities simulation, plasma, wakefield, acceleration 1761
 
  • Á. Ferran Pousa, M. Kirchen, A. Martinez de la Ossa, M. Thévenet
    DESY, Hamburg, Germany
  • S.T.P. Hudson, J.M. Larson
    ANL, Lemont, Illinois, USA
  • A. Huebl, R. Lehé, J.-L. Vay
    LBNL, Berkeley, USA
  • S. Jalas
    University of Hamburg, Hamburg, Germany
 
  When designing a laser-plasma acceleration experiment, one commonly explores the parameter space (plasma density, laser intensity, focal position, etc.) with simulations in order to find an optimal configuration that, for example, minimizes the energy spread or emittance of the accelerated beam. However, laser-plasma acceleration is typically modeled with full particle-in-cell (PIC) codes, which can be computationally expensive. Various reduced models can approximate beam behavior at a much lower computational cost. Although such models do not capture the full physics, they could still suggest promising sets of parameters to be simulated with a full PIC code and thereby speed up the overall design optimization. In this work we automate such a workflow with a Bayesian multitask algorithm, where each task has a different fidelity. This algorithm learns from past simulation results from both full PIC codes and reduced PIC codes and dynamically chooses the next parameters to be simulated. We illustrate this workflow with a proof-of-concept optimization using the Wake-T and FBPIC codes. The libEnsemble library is used to orchestrate this workflow on a modern GPU-accelerated high-performance computing system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST030  
About • Received ※ 08 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 14 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOST032 Status Report of the 50 MeV LPA-Based Injector at ATHENA for a Compact Storage Ring plasma, electron, storage-ring, target 1768
 
  • E. Panofski, C. Braun, J. Dirkwinkel, J.B. Gonzalez, T. Hülsenbusch, A.R. Maier, J. Osterhoff, G. Palmer, P.A. Walker, P. Winkler
    DESY, Hamburg, Germany
  • E. Bründermann, B. Härer, A.-S. Müller, A.I. Papash, C. Widmann
    KIT, Karlsruhe, Germany
  • T.F.J. Eichner, L. Hübner, S. Jalas, L. Jeppe, M. Kirchen, P. Messner, M. Schnepp, M. Trunk, C.M. Werle
    University of Hamburg, Hamburg, Germany
  • M. Kaluza, A. Sävert
    HIJ, Jena, Germany
 
  Laser-based plasma accelerators (LPA) have successfully demonstrated their capability to generate high-energy electron beams with intrinsically short bunch lengths and high peak currents at a setup with a small footprint. These properties make them attractive drivers for a broad range of different applications including injectors for rf-driven, ring-based light sources. In close collaboration the Deutsches Elektronen-Synchrotron (DESY), the Karlsruhe Institute of Technology (KIT) and the Helmholtz Institute Jena aim to develop a 50 MeV plasma injector and demonstrate the injection into a compact storage ring. This storage ring will be built within the project cSTART at KIT. As part of the ATHENA (Accelerator Technology HElmholtz iNfrAstructure) project, DESY will design, setup and operate a 50 MeV plasma injector prototype for this endeavor. This contribution gives a status update of the 50 MeV LPA-based injector and presents a first layout of the prototype design at DESY in Hamburg.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST032  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOST034 Magnetic Characterization of a Superconducting Transverse Gradient Undulator for Compact Laser Wakefield Accelerator-Driven FELs undulator, FEL, electron, wakefield 1772
 
  • K. Damminsek, A. Bernhard, H.J. Cha, A.W. Grau, A.-S. Müller, M.S. Ning, Y. Tong
    KIT, Karlsruhe, Germany
  • S.C. Richter
    CERN, Meyrin, Switzerland
  • R. Rossmanith
    DESY, Hamburg, Germany
 
  Funding: Federal Ministry of Education and Research of Germany and the Development and Promotion of Science and Technology Talents Project (DPST)
A transverse gradient undulator (TGU) is a key component compensating for the relatively large energy spread of Laser Wakefield Accelerator (LWFA)-generated electron beams for realizing a compact Free Electron Laser (FEL). A superconducting TGU with 40 periods has been fabricated at the Karlsruhe Institute of Technology (KIT). In this contribution, we report that the superconducting TGU has been commissioned with nominal operational parameters at an off-line test bench. An experimental set-up for mapping the magnetic field on a two-dimensional grid in the TGU gap has been employed for the magnetic characterization. We show the first preliminary results of these measurements showing the longitudinal quality, the transverse gradient and the transient behaviour of the superconducting TGU field.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST034  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 20 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOST035 Spectroscopic Measurements as Diagnostic Tool for Plasma-Filled Capillaries plasma, electron, acceleration, GUI 1776
 
  • S. Arjmand, L. Crincoli, D. Pellegrini
    INFN/LNF, Frascati, Italy
  • M.P. Anania, A. Biagioni, G. Costa, M. Ferrario, M. Galletti, V.L. Lollo, R. Pompili
    LNF-INFN, Frascati, Italy
  • M. Del Franco
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • D. Giulietti
    UNIPI, Pisa, Italy
  • A. Zigler
    The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
 
  The research concerns the study of the plasma sources for plasma-based accelerators (PBAs) at the SPARC_LAB test-facility (LNF-INFN). The interest in compact accelerators, overcoming the gigantism of the conventional radio-frequency (RF) accelerators, is growing in High Energy Physics. The plasma-based accelerating gradients can attain the GV/m scale. At the SPARC_LAB test-facility, a plasma device is under development. It consists of a capillary in which one or more inlets inject neutral gas (Hydrogen), ionized by a high-voltage (HV) discharge. Electron density has been measured as a function of time through the Stark broadening profiles of the Balmer line.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST035  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 04 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOST041 Physical Aspects of Collinear Laser Injection at SLAC FACET-II E-310: Trojan Horse Experiment plasma, radiation, experiment, electron 1787
 
  • M. Yadav, O. Apsimon, E. Kukstas, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • C.E. Hansel, P. Manwani, B. Naranjo, J.B. Rosenzweig
    UCLA, Los Angeles, USA
  • B. Hidding
    USTRAT/SUPA, Glasgow, United Kingdom
 
  Funding: This work was performed with support of the US Department of Energy, Division of High Energy Physics, un-der Contract No. DE-SC0009914, and the STFC grant ST/P006752/1.
The Facility for Advanced Accelerator Experimental Tests (FACET-II) is a test accelerator infrastructure at SLAC dedicated to the research and development of advanced accelerator technologies. We performed simulations of electron beam driven wakefields, with collinear lasers used for ionization injection of electrons. We numerically generated a witness beam using the OSIRIS code in an up ramp plasma as well as uniform plasma regimes. We report on challenges and details of the E-310 experiment which aims to demonstrate this plasma photocathode injection at FACET-II. We examine the phenomena beam hosing and drive beam depletion. Details of the witness beam generated are discussed. Computation of betatron-radiation X-ray spatial distribution and critical energy are done for FACET-II low emittance beams.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST041  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 23 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOST043 An Effective-Density Model for Accelerating Fields in Laser-Graphene Interactions plasma, target, electron, simulation 1795
 
  • C. Bonțoiu, O. Apsimon, E. Kukstas, C.P. Welsch, M. Yadav
    The University of Liverpool, Liverpool, United Kingdom
  • A. Bonatto
    Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
  • J. Resta-López
    ICMUV, Paterna, Spain
  • G.X. Xia
    UMAN, Manchester, United Kingdom
 
  Funding: This work was supported by STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT)
With the advancement of high-power UV laser technology, the use of nanostructures for particle acceleration attracts renewed interest due to its possibility of achieving TV/m accelerating gradients in solid state plasmas. Electron acceleration in ionized materials such as carbon nanotubes and graphene is currently considered as a potential alternative to the usual laser wakefield acceleration (LWFA) schemes. An evaluation of the suitability of a graphene target for LWFA can be carried out using an effective density model, thus replacing the need to model each layer. We present a 2D evaluation of the longitudinal electric field driven by a short UV laser pulse in a multi-layer graphene structure, showing that longitudinal fields of ~5 TV/m are achievable.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST043  
About • Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 20 June 2022
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WEPOPT021 A Discharge Plasma Source Development Platform for Accelerators: The ADVANCE Lab at DESY plasma, diagnostics, GUI, MMI 1886
 
  • J.M. Garland, R.T.P. D’Arcy, M. Dinter, S. Karstensen, S. Kottler, G. Loisch, K. Ludwig, J. Osterhoff, A. Rahali, A. Schleiermacher, S. Wesch
    DESY, Hamburg, Germany
 
  Novel plasma-based accelerators, as well as advanced, high-gradient beam-manipulation techniques’for example passive or active plasma lenses’require reliable and well-characterized plasma sources, each optimized for their individual task. A very efficient and proven way of producing plasmas for these applications is by directly discharging an electrical current through a confined gas volume. To host the development of such discharge-based plasma sources for advanced accelerators, the ATHENA Discharge deVelopment ANd Characterization Experiment (ADVANCE) laboratory has been established at DESY. In this contribution we introduce the laboratory, give a summary of available infrastructure and diagnostics, as well as a brief overview of current and planned scientific goals.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT021  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
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WEPOPT065 Simulations of the Upgraded Drive-Beam Photoinjector at the Argonne Wakefield Accelerator solenoid, emittance, gun, 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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WEPOTK005 Electromagnetic Analysis of a Circular Storage Ring for Quantum Computing Using Vsim controls, storage-ring, simulation, electromagnetic-fields 2034
 
  • S.I. Sosa Guitron, S. Biedron, T.B. Bolin
    UNM-ECE, Albuquerque, USA
  • S. Biedron
    UNM-ME, Albuquerque, New Mexico, USA
  • K.A. Brown
    BNL, Upton, New York, USA
  • B. Huang
    SBU, Stony Brook, USA
 
  We discuss design considerations for a circular ion trap based on electromagnetic and particle beam simulations. This is a circular radiofrequency quadrupole (rfq) being designed for quantum information applications. The circular rfq should have good electromagnetic properties to accumulate and store the beam for prolonged times, while providing apertures for laser cooling and lower voltage electrodes to provide control over the beam. We use the electromagnetic and particle-in-cell software VSim, which uses finite difference time-domain and particle-in-cell methods, together with high performance computing tools.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK005  
About • Received ※ 30 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 08 July 2022
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WEPOTK019 Status of the Laser Ion Source Upgrade (LION2) at BNL solenoid, target, extraction, plasma 2087
 
  • T. Kanesue, B.D. Coe, S. Ikeda, S.A. Kondrashev, C.J. Liaw, M. Okamura, R.H. Olsen, T. Rodowicz, R. Schoepfer, L. Smart, D. Weiss, Y. Zhang
    BNL, Upton, New York, USA
  • A. Cannavò
    NPI, Řež near Prague, Czech Republic
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, and by the National Aeronautics and Space Administration.
A laser ion source (LION) at Brookhaven National Labor-atory (BNL) has been operational since 2014 to provide low charge state heavy ions of various species for Rela-tivistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Pulsed ion beams (100~300 µs) with beam current ranging from 100 µA to 1 mA from any solid-state targets can be supplied without memory effect of previous beams at pulse-by-pulse basis. LION is an essential device for the operation of a galactic cosmic ray simulator at NSRL together with high-performance beams for RHIC. Because the importance of LION has been widely recognized, an upgraded version of LION, which is called LION2, is being developed for improved performance and reliability. The design and status of the LION2 will be shown.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK019  
About • Received ※ 15 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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WEPOTK020 Slanted Beam Extraction on Laser Ion Source extraction, plasma, solenoid, ion-source 2090
 
  • M. Okamura, S. Ikeda, T. Kanesue, S.A. Kondrashev
    BNL, Upton, New York, USA
  • A. Cannavò
    NPI, Řež near Prague, Czech Republic
 
  Funding: US DOE, Office of Science, under contract DE-SC0012704.
Laser ion sources generate plasma and supply ions by focusing energy by light onto a solid surface. The ionization is achieved during the pulsed laser irradiation period. Then the plasma expands vertically from the target surface as it moves forward. Usually, this drift distance is chosen from tens of centimeters to several meters. Once the required pulse width and plasma density are met, an extraction electric field is applied. In most cases, this electric field is set in the same direction as the direction of the plasma. In this study, we experimentally verify how performance is achieved when the direction of the extraction field is at an angle to the direction of motion of the plasma. If the extraction field can be slanted without degradation of the ion source performance, it is considered to be able to shield neutral vapors and debris generated simultaneously with the plasma, which will be advantageous for the long-term operation of the laser ion source.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK020  
About • Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 26 June 2022
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WEPOTK037 Radiation of a Particle Moving Along a Helical Trajectory in a Resistive-Wall Cylindrical Waveguide GUI, radiation, undulator, electron 2150
 
  • M. Ivanyan, A. Grigoryan, B. Grigoryan, B.K. Sargsyan
    CANDLE SRI, Yerevan, Armenia
  • K. Flöttmann, F. Lemery
    DESY, Hamburg, Germany
  • A. Grigoryan
    YSU, Yerevan, Armenia
 
  Funding: The work was supported by the Science Committee of RA, in the frames of the research project 21T-1C239
The radiation field of a particle moving on a helical trajectory in a cylindrical waveguide with resistive walls is calculated. The deformation of the energy spectrum of radiation, as a result of the finite conductivity of the walls, is investigated.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK037  
About • Received ※ 31 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022
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WEPOMS015 Basic Relations of Laser-Plasma Interaction in the 3D Relativistic, Non-Linear Regime plasma, electron, wakefield, acceleration 2265
 
  • D.F.G. Minenna, E. Bargel, L. Batista, P.A.P. Nghiem
    CEA-IRFU, Gif-sur-Yvette, France
 
  In the approximation where the plasma is considered as a fluid, basic relations are derived to describe the plasma wave driven by an ultra-intense laser pulse. A set of partial differential equations is obtained. It is then numerically solved to calculate the resulting 3D electric field structure that can be used as accelerating cavities for electrons. The laser strength parameter is varied to investigate regimes from weakly nonlinear up to total cavitation where all the initial electrons of the plasma are expelled.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS015  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022
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WEPOMS017 Space Charge Analysis for Low Energy Photoinjector emittance, space-charge, cathode, focusing 2272
 
  • M. Carillo, F. Bosco, E. Chiadroni, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • M. Behtouei, B. Spataro
    LNF-INFN, Frascati, Italy
  • O. Camacho, A. Fukasawa, J.B. Rosenzweig
    UCLA, Los Angeles, USA
  • L. Faillace
    INFN/LNF, Frascati, Italy
  • L. Ficcadenti
    INFN-Roma, Roma, Italy
 
  Funding: This work is supported by DARPA under Contract HR001120C0072, by DOE Contract DE-SC0009914 & DE-SC0020409, by the National Science Foundation Grant N.PHY-1549132 and by INFN through the project ARYA.
Beam dynamics studies are performed in the context of a C-Band hybrid photo-injector project developed by a collab- oration between UCLA/Sapienza/INFN-LNF/RadiaBeam. These studies aim to explain beam behaviour through the beam-slice evolution, using analytical and numerical approaches. An understanding of the emittance oscillations is obtained starting from the slice analysis, which allows correlation of the position of the emittance minima with the slope of the slices in the transverse phase space (TPS). At the end, a significant reduction in the normalized emittance is obtained by varying the transverse shape of the beam while assuming a longitudinal Gaussian distribution. Indeed, the emittance growth due to nonlinear space-charge fields has been found to occur immediately after moment of the beam emission from the cathode, giving insight into the optimum laser profile needed for minimizing the emittance.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS017  
About • Received ※ 16 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOMS020 FAIR SIS100 Laser Cooling Pilot Facility heavy-ion, detector, proton, synchrotron 2284
 
  • S. Klammes, T. Kühl, P.J. Spiller, T. Stöhlker, D.F.A. Winters
    GSI, Darmstadt, Germany
  • M.H. Bussmann, U. Schramm, M. Siebold
    HZDR, Dresden, Germany
  • M.H. Bussmann
    CASUS, Görlitz, Germany
  • J. Gumm, B. Langfeld, T. Walther
    TU Darmstadt, Darmstadt, Germany
  • V. Hannen, K. Ueberholz
    Westfälische Wilhelms-Universität Münster, Institut für Kernphysik, Münster, Germany
  • X. Ma, W.Q. Wen
    IMP/CAS, Lanzhou, People’s Republic of China
  • U. Schramm
    TU Dresden, Dresden, Germany
  • T. Stöhlker
    HIJ, Jena, Germany
  • T. Stöhlker
    IOQ, Jena, Germany
  • T. Walther
    HFHF, Frankfurt am Main, Germany
 
  We present new (preliminary) results from a recent (May 2021) beam experiment for laser cooling of bunched relativistic carbon ion beams at the ESR of the GSI Helmholtz Centre in Darmstadt, Germany. We were able to use the new pulsed UV laser system from the TU Darmstadt, which has a very high repetition rate, a variable pulse duration and high UV power (up to 250 mW @ 257 nm). Using this laser, we have - for the first time - demonstrated laser cooling of bunched relativistic ion beams for different laser pulse durations (166-740 ps) at a ~10 MHz repetition rate. In addition, we could use the moveable in-vacuo (X)UV detection system from Münster University to study the fluorescence from the laser-excited ions. Finally, we have observed clear effects in the amount of detected fluorescence from the ions using our new ion bunch - laser pulse timing scheme. These studies are also highly relevant for the SIS100 laser cooling pilot facility, which is currently being realized at FAIR.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS020  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 13 June 2022
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WEPOMS022 Detailed Analysis of Transverse Emittance of the FLUTE Electron Bunch emittance, simulation, electron, quadrupole 2289
 
  • T. Schmelzer, E. Bründermann, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, N.J. Smale, P. Wesolowski
    KIT, Karlsruhe, Germany
 
  The compact and versatile linear accelerator-based test facility FLUTE (Ferninfrarot Linac- Und Test-Experiment) is operated at KIT. Its primary goal is to serve as a platform for a variety of accelerator R\&D studies like the generation of strong ultra-short terahertz pulses. The amplitude of the generated coherent THz pulses is proportional to the square number of particles in the bunch. With the transverse emittance a measure for the transverse particle density can be determined. It is therefore a vital parameter in the optimization for operation. In a systematic study, the transverse emittance of the electron beam was measured in the FLUTE injector. A detailed analysis considers different influences such as the bunch charge and compares this with particle tracking simulations carried out with ASTRA. In this contribution, the key findings of this analysis are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS022  
About • Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 28 June 2022
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WEPOMS037 Microbunching Studies for the FLASH2020+ Upgrade Using a Semi-Lagrangian Vlasov Solver bunching, simulation, FEL, electron 2334
 
  • Ph. Amstutz, M. Vogt
    DESY, Hamburg, Germany
 
  Precise understanding of the microbunching instability is mandatory for the successful implementation of a compression strategy for advanced FEL operation modes such as the EEHG seeding scheme, which a key ingredient of the FLASH2020+ upgrade project. Simulating these effects using particle-tracking codes can be quite computationally intensive as an increasingly large number of particles is needed to adequately capture the dynamics occurring at small length scales and reduce artifacts from numerical shot-noise. For design studies as well as dedicated analysis of the microbunching instability semi-Lagrangian codes can have desirable advantages over particle-tracking codes, in particular due to their inherently reduced noise levels. However, rectangular high-resolution grids easily become computationally expensive. To this end we developed SelaV1D, a one dimensional semi-Lagrangian Vlasov solver, which employs tree-based domain decomposition to allow for the simulation of entire exotic phase-space densities as they occur at FELs. In this contribution we present results of microbunching studies conducted for the FLASH2020+ upgrade using SelaV1D.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS037  
About • Received ※ 06 June 2022 — Revised ※ 29 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 09 July 2022
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THOXSP2 Brixsino High-Flux Dual X-Ray and THz Radiation Source Based on Energy Recovery Linacs electron, cavity, radiation, linac 2407
 
  • I. Drebot, F. Canella, S. Cialdi, M. Giammarchi, D. Giannotti, S. Latorre, C. Meroni, M. Rossetti Conti, A.R. Rossi, M. Ruijter, S. Samsam, L. Serafini, V. Torri
    INFN-Milano, Milano, Italy
  • M.P. Abbracchio, S. Altilia, B. Paroli, A. Vanzulli
    Universita’ degli Studi di Milano, Milano, Italy
  • A. Andreone, G.P. Papari
    Naples University Federico II, Napoli, Italy
  • A. Bacci, M. Bertucci, A. Bosotti, F. Broggi, D. Giove, P. Michelato, L. Monaco, R. Paparella, L. Rossi, D. Sertore, M. Statera
    INFN/LASA, Segrate (MI), Italy
  • R. Calandrino, A. Delvecchio
    HSP, Milan, Italy
  • S. Capra, D. Cipriani, C. Lenardi, M. Opromolla, E. Suerra, A. Torresin
    Università degli Studi di Milano, Milano, Italy
  • P. Cardarelli, G. Paternò, A. Taibi
    INFN-Ferrara, Ferrara, Italy
  • M. Citterio
    Universita’ degli Studi di Milano e INFN, Milano, Italy
  • A. Esposito
    LNF-INFN, Frascati, Italy
  • R. Ferragut, G. Galzerano
    POLIMI, Milano, Italy
  • C. Koral, M.R. Masullo, A. Passarelli
    INFN-Napoli, Napoli, Italy
  • Z. Mazaheri, G. Mettivier, P. Russo
    UniNa, Napoli, Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
  • P. Paparo
    CNR-ISASI, Pozzuoi, Italy
  • V. Petrillo, F. Prelz, M. Sorbi
    Universita’ degli Studi di Milano & INFN, Milano, Italy
  • B. Piccirillo, A. Rubano
    Naples University Federico II and INFN, Napoli, Italy
  • E. Puppin
    Politecnico/Milano, Milano, Italy
 
  We present the conceptual design of a compact light source named BriXSinO. BriXSinO was born as demonstrator of the Marix project, but it is also a dual high flux radiation source Inverse Compton Source (ICS) of X-ray and Free-Electron Laser of THz spectral range radiation conceived for medical applications and general applied research. The accelerator is a push-pull CW-SC Energy Recovery Linac (ERL) based on superconducting cavities technology and allows to sustain MW-class beam power with almost just one hundred kW active power dissipation/consumption. ICS line produces 33 keV monochromatic X-Rays via Compton scattering of the electron beam with a laser system in Fabry-Pérot cavity at a repetition rate of 100 MHz. The THz FEL oscillator is based on an undulator imbedded in optical cavity and generates THz wavelengths from 15 to 50 micron.  
slides icon Slides THOXSP2 [19.118 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOXSP2  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THOXSP3 Path to High Repetition Rate Seeding: Combining High Gain Harmonic Generation with an Optical Klystron FEL, electron, simulation, klystron 2411
 
  • G. Paraskaki, E. Ferrari, L. Schaper, E. Schneidmiller
    DESY, Hamburg, Germany
  • E. Allaria
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  External seeding in combination with harmonic generation has become a hot topic in the field of high gain free-electron lasers (FELs) since it allows delivery of superior FEL radiation characterized by, for example, full coherence and unprecedented shot-to-shot stability. At low repetition rate machines operating at few 10 Hz, novel experiments have been realized already, however, at superconducting machines, current laser technology does not support exploiting the full repetition rate available. One way to overcome this problem is to reduce the requirements in seed laser power: here, an optical klystron based high gain harmonic generation (HGHG) setup is proposed to reduce the laser peak power requirements by orders of magnitude, enabling operation at drastically increased repetition rates. We report simulation results based on the seeded beamline concept of the FLASH2020+ project. Among other topics, the effect of a linear electron beam energy chirp on this setup will be discussed.  
slides icon Slides THOXSP3 [1.502 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOXSP3  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022
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THPOST013 Development of a Detection System for Quasi-Monochromatic THz Pulse by a Spatially Modulated Electron Beam electron, radiation, timing, cathode 2469
 
  • K. Murakoshi, Y. Koshiba, Y. Tadenuma, P. Wang, M. Washio
    Waseda University, Tokyo, Japan
  • R. Kuroda
    AIST, Tsukuba, Japan
  • K. Sakaue
    The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
 
  We have studied the generation of the broadband THz pulse using a compact linear accelerator. The THz pulse is generated by control of an electron beam angle to Cherenkov radiation angle. In addition, we have succeeded in producing a quasi-monochromatic THz pulse by the spatially modulated electron beam by passing through a slit. This work aims to develop a detection system to elucidate the spectrum of the quasi-monochromatic THz pulse. To detect it stably in a noisy radiation environment, the stability of probe laser system for Electro Optic sampling and timing synchronization system are important. In this conference, the generation method of each THz pulses, the results of development of detection system, and future prospect will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST013  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 24 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, linac, gun, 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOST030 Laser Instrumentation and Insertion Device Measurement System undulator, detector, controls, experiment 2513
 
  • R. Khullar, S.M. Khan, G. Mishra
    Devi Ahilya University, Indore, India
  • M. Gehlot
    MAX IV Laboratory, Lund University, Lund, Sweden
  • H. Jeevakhan
    NITTTR, Bhopal, India
 
  In this paper, we discuss the Hall probe, pulsed wire and stretched wire magnetic measurement systems indigenously developed and installed at the university laboratory at Devi Ahilya Vishwa Vidyalaya, Indore, India. The laser instrumentation such as position measuring detector, laser scanning micrometre, Wollaston interferometer and Michelson interferometer improves the Hall probe sledge alignment and magnet alignment in the undulator thus improves magnet measurement accuracy. The salient features with design specifics of the laser instrumentation along with magnetic measurement system parameters are described with context to some prototype undulators designed and developed in the laboratory.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST030  
About • Received ※ 04 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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THPOPT015 The Design of the Full Energy Beam Exploitation (FEBE) Beamline on CLARA experiment, electron, diagnostics, FEL 2594
 
  • A.R. Bainbridge, D. Angal-Kalinin, J.K. Jones, T.H. Pacey, Y.M. Saveliev, E.W. Snedden
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  The CLARA facility at Daresbury Laboratory was orig-inally designed for the study of novel FEL physics utilis-ing high-quality electron bunches at up to 250 MeV/c. To maximise the exploitation of the accelerator complex, a dedicated full energy beam exploitation (FEBE) beam-line has been designed and is currently being installed in a separate vault on the CLARA accelerator. FEBE will allow the use of high charge (up to 250 pC), moderate energy (up to 250 MeV), electron bunches for a wide variety of accelerator applications critical to ongoing accelerator development in the UK and international communities. The facility consists of a shielded enclo-sure, accessible during beam running in CLARA, with two very large experimental chambers compatible with a wide range of experimental proposals. High-power laser beams (up to 100 TW) will be available for electron-beam interactions in the first chamber, and there are concrete plans for a wide variety of advanced diagnostics (includ-ing a high-field permanent magnet spectrometer and dielectric longitudinal streaker), essential for multiple experimental paradigms, in the second chamber. FEBE will be commissioned in 2024.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT015  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOPT024 MIST - The MESA-Injector Source Two cathode, electron, booster, simulation 2624
 
  • M.A. Dehn, P.S. Plattner
    IKP, Mainz, Germany
  • K. Aulenbacher
    HIM, Mainz, Germany
  • K. Aulenbacher
    GSI, Darmstadt, Germany
  • K. Aulenbacher
    KPH, Mainz, Germany
 
  Funding: Work supported by the German science ministry BMBF through Verbundforschung
The new accelerator MESA (Mainz Energy Recovering Superconducting Accelerator) will provide an average CW electron beam current of up to 10 mA. Operating at 1.3 GHz, this corresponds to a bunch charge of 7.7 pC. The new DC photoemission source MIST is optimized for these requirements. A challenge is heating of the photocathode at high laser power. By a suitable mechanical construction and the use of specific materials, the heat can be dissipated during operation. Options for further improvements are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT024  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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THPOPT025 Photocathode Stress Test Bench at INFN LASA cathode, gun, 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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THPOPT026 Assembly and Characterization of Low-Energy Electron Transverse Momentum Measurement Device (TRAMM) at INFN LASA cathode, electron, emittance, site 2630
 
  • D. Sertore, M. Bertucci, A. Bosotti, D. Giove, L. Monaco, R. Paparella
    INFN/LASA, Segrate (MI), Italy
  • G. Guerini Rocco, C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
 
  In the framework of high-brightness electron beam generation, thermal emittance is nowadays a key parameter. While alkali tellurides are extensively used in advanced electron sources, alkali antimonides photocathodes demonstrated high QE in the visible, thus making feasible CW operations for RF-based photoinjectors. The INFN LASA laboratory in Milan is fully equipped with dedicated production systems for photocathode preparation and optical setup for QE evaluation. In this paper, we describe a newly designed device dedicated to electron transverse momentum measurement (TRAMM). It will be connected to the main production chambers and will serve as an "emittance monitoring" system during photocathode growth. From the design phase, through the parameter estimate, assembly of the components, to the installation and first measurements, we describe the status of this project and its future developments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT026  
About • Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 07 July 2022
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THPOPT028 Dependence of CsK2Sb Photocathode Performance on the Quality of Graphene Substrate Film cathode, electron, synchrotron, synchrotron-radiation 2637
 
  • L. Guo, K. Goto, Y. Takashima
    Nagoya University, Nagoya, Japan
  • H. Yamaguchi
    LANL, Los Alamos, New Mexico, USA
  • M. Yamamoto
    KEK, Ibaraki, Japan
 
  Funding: U.S.-Japan Science and Technology Cooperation Program in High Energy Physics
A photocathode that extracts electrons by irradiating a semiconductor or metal with a laser is applied to advanced accelerators and electron microscopes as a high-performance cathode. In particular, the CsK2Sb photocathode is of interest because it has features such as low emittance, excitability with visible light, and high quantum efficiency. Generally, the CsK2Sb photocathode is produced by depositing a cathode element on a substrate, so that the cathode performance strongly depends on the surface condition of the substrate. We have found graphene as reusable substrate, which has the property of being chemically inactive. In this study, graphene film quality dependence of CsK2Sb photo-cathode performance was evaluated. Specifically, CsK2Sb cathode was deposited using different quality graphene film substrates and their QE values and uniformity were compared. The quality of graphene films was analyzed using X-ray Photoelectron Spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). We found that the graphene film can be cleaned by heating at 500 deg. The QE of the cathode on a good quality graphene film was higher and more uniform than that on a poor quality graphene film.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT028  
About • Received ※ 16 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 24 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOPT029 Study on the Performance Improvement of Alkali Antimonide Photocathodes for Radio Frequency Electron Guns cathode, electron, experiment, ECR 2640
 
  • R. Fukuoka, K. Ezawa, Y. Koshiba, M. Washio
    Waseda University, Tokyo, Japan
  • K. Sakaue
    The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
 
  Semiconductor photocathodes such as Cs-Te and Cs-K-Sb are used as electron sources in accelerators to generate high brightness beams using radio frequency (rf) electron guns. Alkali antimonide photocathodes have a high quantum efficiency (Q.E.) of ~10%, and their excitation wavelength is in the visible light region (532 nm), so that they are expected to reduce the requirements on the optical system and increase the amount of charge compared to Cs-Te. However, alkali antimonide photocathodes have a short lifetime and degrade under poor vacuum conditions, so it is essential to improve durability by protective film coatings. Therefore, we are currently working on the fabrication of high Q.E. alkali antimonide photocathodes that can withstand the Q.E. reduction during coating. In this presentation, we will report the results of comparison between the fabricated alkali antimonide photocathode and Cs-Te photocathode, and future prospects.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT029  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOPT032 SUNDAE2 at EuXFEL: A Test Stand to Characterize the Magnetic Field of Superconducting Undulators undulator, vacuum, FEL, experiment 2649
 
  • J.E. Baader, S. Abeghyan, S. Casalbuoni, D. La Civita, B. Marchetti, M. Yakopov, P. Ziolkowski
    EuXFEL, Schenefeld, Germany
  • H.-J. Eckoldt, A. Hauberg, S. Lederer, L. Lilje, T. Wohlenberg, R. Zimmermann
    DESY, Hamburg, Germany
  • A.W. Grau
    KIT, Eggenstein-Leopoldshafen, Germany
 
  European XFEL foresees a superconducting undulator (SCU) afterburner in the SASE2 hard X-ray beamline. It consists of six 5m-long undulator modules with a 5mm vacuum gap, where each module contains two 2m-long coils and one phase shifter. Prior to installation, the magnetic field must be mapped appropriately. Two magnetic measurement test stands named SUNDAE 1 and 2 (Superconducting UNDulAtor Experiment) are being developed at European XFEL. While SUNDAE1 will be a vertical test stand to measure SCU coils up to two meters with Hall probes in a liquid or superfluid helium bath, SUNDAE2 will measure the SCU coils assembled in the final cryostat. This contribution presents the development status of SUNDAE2 and its main requirements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT032  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOPT042 Studies for a Laser Wakefield Driven Injector at ELSA synchrotron, booster, linac, plasma 2686
 
  • K. Kranz, K. Desch, D. Elsner, M.T. Switka
    ELSA, Bonn, Germany
 
  At the University of Bonn, Germany, the storage ring ELSA extracts electrons with energies up to 3.2 GeV to hadron physics and novel detector testing experiments. We study the feasibility of replacing the current 26 MeV LINAC injector with a laser wakefield accelerator (LWA). For this, contemporary parameters from current LWA setups at other laboratories are assumed and matched to the acceptance of the booster synchrotron. Moreover, a conceptional draft of a potential LWA setup is created. This takes into consideration the influence of building conditions such as available floor space and building vibrations to estimate a setup and laser beam stability of a plasma generating high power laser system and beamline to the plasma cell. The methods and intermediate results of this study will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT042  
About • Received ※ 08 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOTK041 Development of Programmable Bipolar Multi kHz Kicker Drivers for Long Pulse Superconducting Electron Linacs kicker, FEL, electron, gun 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOTK053 Foiled Again: Solid-State Sample Delivery for High Repetition Rate XFELs target, FEL, experiment, controls 2899
 
  • N. Majernik, N. Inzunza, P. Manwani, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • R.B. Agustsson, A. Moro
    RadiaBeam, Santa Monica, California, USA
  • R. Ash, N.B. Welke
    UW-Madison/PD, Madison, Wisconsin, USA
  • U. Bergmann, A. Halavanau, C. Pellegrini
    SLAC, Menlo Park, California, USA
 
  Funding: Department of Energy DE-SC0009914 and DE-AC02-76SF00515
XFELs today are capable of delivering high intensity pulse trains of x-rays with up-to MHz to sub-GHz frequency. These x-rays, when focused, can ablate a sample in a single shot, requiring the sample material to be replaced in time for the next shot. For some applications, especially serial crystallography, the sample may be renewed as a dilute solution in a high speed jet. Here, we describe the development and characterization of a system to deliver solid state sample material to an XFEL nanofocus. The first application of this system will be an x-ray laser oscillator operating at the copper Kα line with a ~30 ns cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK053  
About • Received ※ 06 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 02 July 2022
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THPOTK059 Laser System for SuperKEKB RF Gun in Phase III Commissioning electron, MMI, injection, gun 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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THPOTK061 Machine Learning Approach to Temporal Pulse Shaping for the Photoinjector Laser at CLARA network, target, experiment, electron 2917
 
  • A.E. Pollard, D.J. Dunning, W.A. Okell, E.W. Snedden
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  The temporal profile of the electron bunch is of critical importance in accelerator areas such as free-electron lasers and novel acceleration. In FELs, it strongly influences factors including efficiency and the profile of the photon pulse generated for user experiments, while in novel acceleration techniques it contributes to enhanced interaction of the witness beam with the driving electric field. Work is in progress at the CLARA facility at Daresbury Laboratory on temporal shaping of the ultraviolet photoinjector laser, using a fused-silica acousto-optic modulator. Generating a user-defined (programmable) time-domain target profile requires finding the corresponding spectral phase configuration of the shaper; this is a non-trivial problem for complex pulse shapes. Physically informed machine learning models have shown great promise in learning complex relationships in physical systems, and so we apply machine learning techniques here to learn the relationships between the spectral phase and the target temporal intensity profiles. Our machine learning model extends the range of available photoinjector laser pulse shapes by allowing users to achieve physically realisable configurations for arbitrary temporal pulse shapes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK061  
About • Received ※ 30 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 03 July 2022
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THPOTK062 Thermal Modeling and Benchmarking of Crystalline Laser Amplifiers simulation, experiment, software, ECR 2921
 
  • D.T. Abell, D.L. Bruhwiler, P. Moeller, R. Nagler, B. Nash, I.V. Pogorelov
    RadiaSoft LLC, Boulder, Colorado, USA
  • Q. Chen, C.G.R. Geddes, C. Tóth, J. van Tilborg
    LBNL, Berkeley, USA
  • N.B. Goldring
    STATE33 Inc., Portland, Oregon, USA
 
  Funding: This work is supported by the US Department of Energy, Office of High Energy Physics under Award Numbers DE-SC0020931 and DE-AC02-05CH11231.
Ti:sapphire crystals constitute the lasing medium of a class of lasers valued for their wide tunability and ultra-short, ultra-high intensity pulses. When operated at high power and high repetition rate (1kHz), such lasers experience multiple effects that can degrade performance. In particular, thermal gradients induce a spatial variation in the index of refraction, hence thermal lensing*. Using the open-source finite-element code FEniCS***, we solve the relevant partial differential equations to obtain a quantitative measure of the disruptive effects of thermal gradients on beam quality. We present thermal simulations of a pump laser illuminating a Ti:sapphire crystal. From these simulations we identify the radial variation in the refractive index, and hence the extent of thermal lensing. In addition, we present analytic models used to estimate the effect of thermal gradients on beam quality. This work generalizes to other types of crystal amplifiers.
* S. Cho, et al., Appl. Phys. Express, 11:092701, 2018.
** M. Born & E. Wolf, Principles of Optics, Cambridge Univ. Press, 1980.
*** The FEniCS computing platform, https://fenicsproject.org
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK062  
About • Received ※ 13 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOTK063 Open Source Software to Simulate Ti:Sapphire Amplifiers simulation, optics, photon, experiment 2925
 
  • D.L. Bruhwiler, D.T. Abell, B. Nash
    RadiaSoft LLC, Boulder, Colorado, USA
  • Q. Chen, C.G.R. Geddes, C. Tóth, J. van Tilborg
    LBNL, Berkeley, USA
  • N.B. Goldring
    STATE33 Inc., Portland, Oregon, USA
 
  Funding: This work is supported by the US Department of Energy, Office of High Energy Physics under Award Numbers DE-SC0020931 and DE-AC02-05CH11231.
The design of next-generation PW-scale fs laser systems, including scaling to kHz rates and development of new laser gain media for efficiency, will require parallel multiphysics simulations with realistic errors and nonlinear optimization. There is currently a lack of broadly available modeling software that self-consistently captures the required physics of gain, thermal loading and lensing, spectral shaping, and other effects required to quantitatively design such lasers.* We present initial work towards an integrated multiphysics capability for modeling pulse amplification in Ti:Sa lasers. All components of the software suite are open source. The Synchrotron Radiation Workshop (SRW)** is being used for physical optics, together with Python utilities. The simulations are being validated against experiments.
* R. Falcone et al., Brightest Light Initiative Workshop Report (2019).
** https://github.com/ochubar/srw
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK063  
About • Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022
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THPOMS036 HERACLES: A High Average Current Electron Beamline for Lifetime Testing of Novel Photocathodes cathode, gun, electron, vacuum 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOMS046 Generation of Flat-Laser Compton Scattering Gamma-ray Beam in UVSOR undulator, electron, simulation, experiment 3070
 
  • H. Ohgaki, K. Ali, T. Kii, H. Zen
    Kyoto University, Kyoto, Japan
  • M. Fujimoto, Y. Taira
    UVSOR, Okazaki, Japan
  • T. Hayakawa, T. Shizuma
    QST, Tokai, Japan
 
  Funding: This work is supported by JSPS KAKENHI Grant Number 21H01859. A part of this work was performed at the BL1U of UVSOR, IMS, Okazaki (IMS program 21-603).
Flat energy distribution Laser Compton scattering (F-LCS) gamma-ray beam, which has a flat distribution in the energy spectrum and the spatial distribution with a small beam size, has been developed to study an isotope selective CT Imaging application at the beamline BL1U in UVSOR. We have successfully demonstrated a three-dimensional (3D) isotope-selective CT image by using a conventional LCS gamma-ray beam[1]. However, the conventional LCS beam with a small beam size whose energy spread is narrow can’t excite a few isotopes at the same time. Therefore, we proposed the F-LCS gamma-ray beam by using the Apple-II undulator installed in BL1U in UVSOR to excite a circular motion of the electron beam. An EGS5 simulation shows that a weak magnetic field (K=0.2) can generate an F-LCS beam. The demonstration experiments have been carried out in UVSOR and the spectra of generated LCS beam with different K-values of the undulator were measured. As a result, the measured spectra agreed with the EGS5 simulation. The principle of F-LCS generation and experimental results, including the effect on the stored electron beam, will be presented at the conference.
[1] K. Ali, et. al., "Three-dimensional nondestructive isotope-selective tomographic imaging of 208Pb distribution via nuclear resonance fluorescence". Appl. Sci. 2021, 11, 3415.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS046  
About • Received ※ 02 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOMS060 Development of Analytical Light Source for Construction of Femtosecond Pulse Radiolysis System Using Er Fiber Laser radiation, FEM, injection, pulse-stretcher 3109
 
  • Y. Kaneko, Y. Koshiba, K. Sakaue, M. Sato, M. Washio
    Waseda University, Tokyo, Japan
  • K. Sakaue
    The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
 
  We are trying to elucidate the initial process of radiation chemical reactions, which is considered to be an unknown area. One of the methods to elucidate this initial process is pulse radiolysis. In pulse radiolysis, a substance is irradiated with ionizing radiation and at the same time irradiated with analytical light, and the absorption spectrum of the light can be traced back in time to the active species. However, the radiation chemical reaction starts in a very short time, and the pulse radiolysis system needs to have the same time resolution. Therefore, the analytical light should be ultra-short pulses. In addition, the absorption wavelength of the substance is not always known. Hence, the wavelength range of the analytical light should be broad. Since the absorption wavelengths of important active species are in the visible light region, it is desirable to cover the visible light region as well. We believe that supercontinuum light generated from the second harmonic of the Er fiber laser is the best analytical light to meet these requirements. In this presentation, we describe the current status of the development of the supercontinuum light generation and future prospects.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS060  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
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