IPAC2022 - List of Keywords (positron)

Paper	Title	Other Keywords	Page
MOPLXGD3	The Accelerator and Beam Physics of the Muon g-2 Experiment at Fermilab	storage-ring, experiment, lattice, betatron	10
	D.A. Tarazona Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The physics case of the Muon g-2 Experiment at Fermilab is outstanding and has recently attracted significant attention from its first official results. Although its measurements involve high energy physics methods, such as counting positron production rates with the use of calorimeters and beam diagnostics with tracking detectors, this experiment is strongly bound to accelerator and beam physics. This paper reviews the principles of the experiment and the details necessary to provide a solid ground for the beam-dynamics uncertainties and the corrections of the systematic effects influencing the output of the experiment: a single numerical value, which may unveil new physics.
	Slides MOPLXGD3 [29.311 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPLXGD3
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 09 July 2022
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MOPOTK012	Concept of a Polarized Positron Source for CEBAF	electron, target, cavity, experiment	457
	S.H. Habet, R.M. Bodenstein, S.A. Bogacz, J.M. Grames, A.S. Hofler, R. Kazimi, F. Lin, M. Poelker, Y. Roblin, A. Seryi, R. Suleiman, A.V. Sy, D.L. Turner JLab, Newport News, Virginia, USA A. Ushakov Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France C.A. Valerio-Lizárraga ECFM-UAS, Culiacan, Sinaloa, Mexico E.J-M. Voutier LPSC, Grenoble Cedex, France
	Funding: Laboratoire de Physique des 2 Infinis Irène Joliot-Curie Université Paris-Saclay -> Eric Voutier : eric.voutier@ijclab.in2p3.fr. Positron beams would provide new and meaningful probes for the experimental program at the Thomas Jefferson National Accelerator Facility (JLab), including but not limited to future hadronic physics and dark matter experiments. Critical requirements involve generating positron beams with a high degree of spin polarization, sufficient intensity and a continuous-wave (CW) bunch train compatible with acceleration to 12 GeV at the Continuous Electron Beam Accelerator Facility (CEBAF). To address these requirements, a polarized positron injector based upon the bremsstrahlung of an intense CW spin polarized electron beam is considered. First a polarized electron beam line provides >1 mA of polarized electrons at ~120 MeV to a high-power target for positron production. Next, a second beam line collects, shapes and aligns the spin of positrons for users. Finally, the positron beam is matched into the CEBAF acceptance for acceleration and transport to the end stations with energies up to 12 GeV. An optimized layout to provide positrons beams with intensity >100 nA (polarized) or intensity >3 µA (unpolarized) will be discussed in this poster. D. Abbott et al., "Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies", Phys. Rev. Lett., 116, 214801 (2016)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK012
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 06 July 2022
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TUIZSP1	Status of the e⁺e⁻ Collider Projects in Asia and Europe: CEPC and FCC-ee	collider, cavity, booster, operation	815
	X.C. Lou IHEP, Beijing, People’s Republic of China M. Boscolo LNF-INFN, Frascati, Italy F. Zimmermann CERN, Meyrin, Switzerland
	Since the Higgs boson discovery at CERN, precision measurement of its properties has become the first priority in the field of High Energy Physics. Two laboratories, CERN from Europe and IHEP from China, have proposed large scale circular electron-positron colliders, namely FCC-ee and CEPC. Record luminosities are expected in the center of mass energy range from 90 to about 365 GeV. In this talk the statuses of both projects are reviewed: Following the publication of the first CDR FCC-ee and CEPC entering the phase of consolidation and feasibility study. Special focus will be put on R&D plans, prototyping and key technologies.
	Slides TUIZSP1 [6.718 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP1
About •	Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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WEOXGD3	An Alternative Design for BEPCII Upgrade	cavity, lattice, survey, emittance	1591
	H. Geng, J. Xing, C.H. Yu, Y. Zhang IHEP, Beijing, People’s Republic of China
	The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high energy physics study. Along with the deepening of the research, more important physics is expected in higher energy region (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1 GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. The baseline design which kept the survey of the North Collision Region (NCR) unchanged for the upgrade of BEPCII has been studied in previous work. In this paper, we show an alternative design that modifies the survey of NCR, but enables the online maintenance of both RF cavities in each ring of BEPCII. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of BEPCII beam with reasonable margin.
	Slides WEOXGD3 [3.761 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD3
About •	Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022
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WEPOST009	Muon Collider Based on Gamma Factory, FCC-ee and Plasma Target	plasma, electron, emittance, target	1691
	F. Zimmermann, A. Latina CERN, Meyrin, Switzerland M. Antonelli, M. Boscolo LNF-INFN, Frascati, Italy A.P. Blondel DPNC, Genève, Switzerland J.P. Farmer MPI-P, München, Germany
	Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730 (iFAST). The LEMMA-type muon collider generates muon pairs by the annihilation of 45 GeV positrons with electrons at rest. Due to the small cross section, an extremely high rate of positrons is required, which could be achieved by a ’Gamma factory’ based on the LHC. Other challenges with the LEMMA-type muon production scheme include the emittance preservation of muons and muon-generating positrons upon multiple traversals through a target, and the merging of many separate muon bunchlets. These two challenges may potentially be overcome by (1) operating the FCC-ee booster with a barrier bucket and induction acceleration, so that all positrons of a production cycle are merged into one single superbunch instead of storing ~10,000 separate bunches; and (2) sending the positron superbunch into a plasma target. During the passage of the positron superbunch, the electron density is enhanced 100–1000 fold without any increase in the density of nuclei, so that beamstrahlung and Coulomb scattering are essentially absent. We investigate prospects and difficulties of this approach, including emittance growth due to filamentation in the nonlinear plasma channel and due to positron self-modulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST009
About •	Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 05 July 2022
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WEPOST040	Comparing Methods of Recovering Gamma Energy Distributions from PEDRO Spectrometer Responses	photon, electron, site, scattering	1784
	M.H. Oruganti, B. Naranjo, J.B. Rosenzweig, M. Yadav UCLA, Los Angeles, California, USA
	To calculate the energy levels of the photons emitted from high-energy particle interactions, the new pair spectrometer (PEDRO) channels the photons through several Beryllium nuclear fields to produce electron-positron pairs through the nuclear field interaction. This project compared several methods of reconstruction and determined which best predicts original energy distributions based on simulated spectra. These methods included using Maximum Likelihood Estimation, Machine Learning, and directly analyzing a response matrix that modeled PEDRO’s response to any photon energy distribution. We report that performing the direct analysis, also known as QR decomposition, on a PEDRO-generated spectrum provides by far the most accurate calculation of the spectrum’s original energy distribution. These methods were tested against results from experimental cases, including Nonlinear Compton Scattering and Filamentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST040
About •	Received ※ 15 June 2022 — Revised ※ 01 July 2022 — Accepted ※ 08 July 2022 — Issue date ※ 08 July 2022
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WEPOPT017	First Optics Design for a Transverse Monochromatic Scheme for the Direct S-Channel Higgs Production at FCC-ee Collider	optics, collider, luminosity, site	1878
	H.P. Jiang Harbin Institute of Technology (HIT) , Harbin, People’s Republic of China A. Faus-Golfe, Z.D. Zhang Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France K. Oide KEK, Ibaraki, Japan Z.D. Zhang IHEP, Beijing, People’s Republic of China Z.D. Zhang UCAS, Beijing, People’s Republic of China F. Zimmermann CERN, Meyrin, Switzerland
	The FCC-ee collider baseline foresees four different energy operation modes: Z, WW, H(ZH) and ttbar. An optional fifth mode, called s-channel Higgs production mode, could allow the measurement of the electron Yukawa coupling, in dedicated runs at 125 GeV centre-of-mass energy, provided that the centre-of-mass energy spread, can be reduced by at least an order of magnitude (5-10 MeV). The use of a special collision technique: a monochromatization scheme is one way to accomplish it. There are several methods to implement a monochromatization scheme. One method, named transverse monochromatization scheme, consists of introducing a dispersion different from zero but opposite sign for the two colliding beams at the Interaction Point (IP); In this paper we will report about the first attempt to design a new optics to implement a transverse monochromatic scheme for the FCC-ee Higgs production totally compatible with the standard mode of operation without dispersion at the IP.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT017
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022
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WEPOPT023	A Design of ILC E-Driven Positron Source	cavity, electron, linac, acceleration	1889
	M. Kuriki, S. Konno, Z.J. Liptak HU/AdSM, Higashi-Hiroshima, Japan M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan H. Tajino HU ADSE, Hiroshima, Japan T. Takahashi Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	ILC is an electron-positron linear collider based on Superconducting linear accelerator. Linear collider is an only solution to realinze high energy electron-positron collision beyond the limit of synchrotron radiation energy loss by ring colliders. Beam current of injector of linear colliders is much larger than that of ring colliders because the beam is not reusable. Providing an enough amount of particles, especially positron is a technical issue. In this article, we present a design of electron driven positron source for ILC. After optimizations, the system design is established with an enough technical margin, e.g. avoiding potential damage on the production target.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT023
About •	Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 23 June 2022
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WEPOPT024	Beam Loading Compensation of Standing Wave Linac with Off-Crest Acceleration	cavity, beam-loading, acceleration, klystron	1893
	M. Kuriki, S. Konno, Z.J. Liptak HU/AdSM, Higashi-Hiroshima, Japan M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan H. Tajino HU ADSE, Hiroshima, Japan T. Takahashi Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	In E-Driven positron source of ILC, the generated positron is captured by a standing wave cavity. Because the deceleration capture method is employed, the positron is off-crest over the linac. Because the beam-loading is expected to be more than 1A in a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation controlling the timing doesn’t work because RF and Beam induced field are in different phase. In this manuscript, we discuss the compensation with the off-crest acceleration case. A simple phase modulation on the input RF is a solution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT024
About •	Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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WEPOPT046	Preparation of a Prototype Plasma Lens as an Optical Matching Device for the ILC e⁺ Source	plasma, simulation, focusing, optical-matching	1961
	M. Formela, N. Hamann, G.A. Moortgat-Pick University of Hamburg, Hamburg, Germany K. Flöttmann, G. Loisch, G.A. Moortgat-Pick DESY, Hamburg, Germany
	In recent years, high-gradient, symmetric focusing with active plasma lenses has regained significant interest due to the potential advantages in compactness and beam dynamics compared to conventional focusing elements. One potential application is the optical matching of highly divergent positrons from the undulator-based ILC positron source into the downstream accelerating structures. A collaboration between University Hamburg and DESY Hamburg has been established to develop a prototype design for this application. Here, we discuss beam dynamics simulation results, preliminary parameters of the lens prototype, and the current status of the prototype design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT046
About •	Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 17 June 2022
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WEPOPT054	Target Studies for the FCC-ee Positron Source	target, radiation, electron, photon	1979
	F. Alharthi, I. Chaikovska, R. Chehab, S. Ogur, A. Ushakov, S. Wallon Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France L. Bandiera, A. Mazzolari, M. Romagnoni, A.I. Sytov INFN-Ferrara, Ferrara, Italy J. Diefenbach, W. Lauth IKP, Mainz, Germany O. Khomyshyn Taras Shevchenko National University of Kyiv, Kyiv, Ukraine D.M. Klekots National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine V.V. Mytrochenko NSC/KIPT, Kharkov, Ukraine P. Sievers, Y. Zhao CERN, Meyrin, Switzerland M. Soldani Università degli Studi di Ferrara, Ferrara, Italy
	FCC-ee injector study foresees 3.5~nC electron and positron bunches with 200 Hz repetition and 2 bunches per linac pulse at 6~GeV extraction energy. Regarding the possible options of positron production, we retain both of the conventional amorphous target and the hybrid target options. The hybrid scheme uses an intense photon production by 6 GeV electrons impinging on a crystal oriented along a lattice axis. In such a way, it involves two targets: a crystal as a photon radiator and an amorphous target-converter. Therefore, to avoid early failure or damage of the target, the candidate materials for the crystal and conversion targets have started to be tested by using the intense electron beam at Mainzer Mikrotron in Germany by the end of 2021. By manipulating the beam intensity, focusing, and chopping, a Peak Energy Deposition Density in the tested targets could be achieved close to that generated by the electron/photon beam in the FCC-ee positron target. Radiation-damage studies of the crystal sample have been also performed allowing estimating the effect on the photon enhancement used in the hybrid positron source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT054
About •	Received ※ 16 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022
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WEPOPT062	Optimisation of the FCC-ee Positron Source Using a HTS Solenoid Matching Device	solenoid, target, linac, simulation	2003
	Y. Zhao, S. Döbert, A. Latina, S. Ogur CERN, Meyrin, Switzerland B. Auchmann, P. Craievich, J. Kosse, R. Zennaro PSI, Villigen PSI, Switzerland I. Chaikovska, R. Chehab Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France M. Duda IFJ-PAN, Kraków, Poland P.V. Martyshkin BINP SB RAS, Novosibirsk, Russia
	In this paper, we present the simulation and optimisation of the FCC-ee positron source, where a high-temperature superconducting (HTS) solenoid is used as the matching device to collect positrons from the target. The "conventional" target scheme is used which simply consists of amorphous tungsten. The target is placed inside the bore of the HTS solenoid to improve the accepted positron yield at the entrance of the damping ring and the location of the target is optimised. The latest recommended baseline beam parameters are used and presented. An optimisation of the ideal positron yield using the analytic SC solenoid on-axis field is also performed and shows that the design of the HTS solenoid is optimal as far as the accepted positron yield is concerned.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT062
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022
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WEPOPT063	The FCCee Pre-Injector Complex	linac, electron, injection, collider	2007
	P. Craievich, B. Auchmann, S. Bettoni, H.-H. Braun, M. Duda, D. Hauenstein, E. Hohmann, R. Ischebeck, P.N. Juranič, J. Kosse, G.L. Orlandi, M. Pedrozzi, J.-Y. Raguin, S. Reiche, S.T. Sanfilippo, M. Schaer, N. Vallis, R. Zennaro PSI, Villigen PSI, Switzerland F. Alharthi, I. Chaikovska, S. Ogur Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France W. Bartmann, M. Benedikt, M.I. Besana, M. Calviani, S. Döbert, Y. Dutheil, O. Etisken, J.L. Grenard, A. Grudiev, B. Humann, A. Latina, A. Lechner, K. Oide, A. Perillo-Marcone, H.W. Pommerenke, R.L. Ramjiawan, Y. Zhao, F. Zimmermann CERN, Meyrin, Switzerland A. De Santis INFN/LNF, Frascati, Italy Y. Enomoto, K. Furukawa, K. Oide KEK, Ibaraki, Japan O. Etisken Kirikkale University, Kirikkale, Turkey C. Milardi LNF-INFN, Frascati, Italy T.O. Raubenheimer SLAC, Menlo Park, California, USA N. Vallis EPFL, Lausanne, Switzerland
	The international FCC study group published in 2019 a Conceptual Design Report for an electron-positron collider with a centre-of-mass energy from 90 to 365 GeV with a beam currents of up to 1.4 A per beam. The high beam current of this collider create challenging requirements on the injection chain and all aspects of the linac need to be carefully reconsidered and revisited, including the injection time structure. The entire beam dynamics studies for the full linac, damping ring and transfer lines are major activities of the injector complex design. A key point is that any increase of positron production and capture efficiency reduces the cost and complexity of the driver linac, the heat and radiation load of the converter system, and increases the operational margin. In this paper we will give an overview of the status of the injector complex design and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration. In this framework, furthermore, we also present the preliminary studies of the FCC-ee positron source highlighting the main requirements and constraints.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT063
About •	Received ※ 11 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022
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THPOST003	Collective Effects Estimates for the Damping Ring Design of the FCC-ee	electron, emittance, impedance, damping	2435
	O. Etisken Ankara University, Faculty of Sciences, Ankara, Turkey F. Antoniou, F. Zimmermann CERN, Meyrin, Switzerland A. De Santis INFN/LNF, Frascati, Italy C. Milardi LNF-INFN, Frascati, Italy
	The current injector complex design of the FCC-e⁺e⁻ project consists of e⁺/e⁻ linacs, which accelerate the beams up to 6 GeV, a damping ring at 1.54 GeV, a pre-booster ring, accelerating the beam up to 16 GeV and a booster synchrotron ring integrated in the collider tunnel accelerating the beams up to the collision energies. The purpose of the damping ring is to accept the 1.54 GeV beam coming from the linac-1, damp the positron/electron beams and provide the required beam characteristics for the injection into the linac-2. In this presentation the current damping ring design is introduced and analytical calculations on various collective effect such as space charge, intra-beam scattering, longitudinal micro-wave instability, transverse mode coupling instability, ion effects, electron cloud and coherent synchrotron radiation, are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST003
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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THPOST011	SuperKEKB Electron Positron Injector Linac Upgrade for Higher Charge and Lower Emittance	linac, emittance, electron, injection	2461
	K. Furukawa, H. Ego, Y. Enomoto, N. Iida, T. Kamitani, M. Kawamura, S. Matsumoto, T. Matsumoto, T. Miura, M. Satoh, A. Shirakawa, T. Suwada, M. Yoshida KEK, Ibaraki, Japan
	KEK electron positron injector linac has established simultaneous top-up injections in 2019 for 5 rings of SuperKEKB DR, LER, HER, PF ring and PF-AR as a base of the both elementary particle physics and photon science experiments even under a quite short beam lifetime. It improved the injection stabilities while the SuperKEKB broke the world record of the collision luminosity of the previous project KEKB. As the collision performance improves, the beam-beam effect makes the dynamic aperture shrink, and the beam lifetime reduces further. Thus, it became inevitable for the injector to be upgraded in order to resolve the contradictory improvements of higher charge and lower emittance of injection beams regarding beam wakefield till 2025. The upgrade plan is described including pulsed magnets, an energy compression system, accelerating structures, girders, positron generator and so on.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST011
About •	Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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THPOST012	Achievement of 200, 000 Hours of Operation at KEK 7-GeV Electron 4-GeV Positron Injector Linac	injection, linac, operation, electron	2465
	K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, Y. Enomoto, T. Higo, H. Honma, N. Iida, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, S. Matsumoto, T. Matsumoto, H. Matsushita, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, T. Natsui, Y. Ogawa, S. Ohsawa, Y. Okayasu, T. Oogoe, M.A. Rehman, I. Satake, M. Satoh, Y. Seimiya, T. Shidara, A. Shirakawa, H. Someya, T. Suwada, M. Tanaka, D. Wang, Y. Yano, K. Yokoyama, M. Yoshida, T. Yoshimoto, R. Zhang, X. Zhou KEK, Ibaraki, Japan Y. Bando Sokendai, Ibaraki, Japan
	KEK electron positron injector linac initiated the injection operation into Photon Factory (PF) light source in 1982. Since then for 39 years, it has served for multiple projects, namely, TRISTAN, PF-AR, KEKB, and SuperKEKB. Its total operation time has accumulated 200 thousand hours on May 7, 2020. We are extremely proud of the achievement following continuous efforts by our seniors. The construction of the injector linac started in 1978, and it was commissioned for PF with 2.5 GeV electron in 1982. In parallel, the positron generator linac was constructed for the TRISTAN collider project. The slow positron facility was also commissioned in 1992. After the KEKB asymmetric-energy collider project was commissioned in 1998 with direct energy injections, the techniques such as two-bunch acceleration and simultaneous injection were developed. As the soft structure design of the linac was too weak against the great east Japan earthquake, it took three years to recover. Then the construction and commissioning for the SuperKEKB project went on, and the simultaneous top-up injection into four storage rings contributes to the both elementary particle physics and photon science.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST012
About •	Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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THPOTK048	Radiation Load Studies for the FCC-ee Positron Source with a Superconducting Matching Device	target, collider, shielding, electron	2879
	B. Humann TU Vienna, Wien, Austria B. Auchmann, J. Kosse PSI, Villigen PSI, Switzerland I. Chaikovska, S. Ogur Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France B. Humann, A. Latina, A. Lechner, Y. Zhao CERN, Meyrin, Switzerland
	For an electron-positron collider like FCC-ee, the production of positrons plays a crucial role. One of the design options considered for the FCC-ee positron source employs a superconducting solenoid made of HTS coils as an adiabatic matching device. The solenoid, which is placed around the production target, is needed to capture positrons before they can be accelerated in a linear accelerator. A superconducting solenoid yields a higher peak field than a conventional-normal conducting magnetic flux concentrator, therefore increasing the achievable positron yield. In order to achieve an acceptable positron production, the considered target is made of tungsten-rhenium, which gives also a significant flux of un-wanted secondary particles, that in turn could generate a too large radiation load on the superconducting coils. In this study, we assess the feasibility of such a positron source by studying the heat load and long-term radiation damage in the superconducting matching device and surrounding structures. Results are presented for different geometric configurations of the superconducting matching device.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK048
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 07 July 2022
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Paper

Title

Other Keywords

Page

MOPLXGD3

The Accelerator and Beam Physics of the Muon g-2 Experiment at Fermilab

storage-ring, experiment, lattice, betatron

10

D.A. Tarazona
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The physics case of the Muon g-2 Experiment at Fermilab is outstanding and has recently attracted significant attention from its first official results. Although its measurements involve high energy physics methods, such as counting positron production rates with the use of calorimeters and beam diagnostics with tracking detectors, this experiment is strongly bound to accelerator and beam physics. This paper reviews the principles of the experiment and the details necessary to provide a solid ground for the beam-dynamics uncertainties and the corrections of the systematic effects influencing the output of the experiment: a single numerical value, which may unveil new physics.

Slides MOPLXGD3 [29.311 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPLXGD3

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 09 July 2022

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MOPOTK012

Concept of a Polarized Positron Source for CEBAF

electron, target, cavity, experiment

457

S.H. Habet, R.M. Bodenstein, S.A. Bogacz, J.M. Grames, A.S. Hofler, R. Kazimi, F. Lin, M. Poelker, Y. Roblin, A. Seryi, R. Suleiman, A.V. Sy, D.L. Turner
JLab, Newport News, Virginia, USA
A. Ushakov
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
C.A. Valerio-Lizárraga
ECFM-UAS, Culiacan, Sinaloa, Mexico
E.J-M. Voutier
LPSC, Grenoble Cedex, France

Funding: Laboratoire de Physique des 2 Infinis Irène Joliot-Curie Université Paris-Saclay -> Eric Voutier : eric.voutier@ijclab.in2p3.fr.
Positron beams would provide new and meaningful probes for the experimental program at the Thomas Jefferson National Accelerator Facility (JLab), including but not limited to future hadronic physics and dark matter experiments. Critical requirements involve generating positron beams with a high degree of spin polarization, sufficient intensity and a continuous-wave (CW) bunch train compatible with acceleration to 12 GeV at the Continuous Electron Beam Accelerator Facility (CEBAF). To address these requirements, a polarized positron injector based upon the bremsstrahlung of an intense CW spin polarized electron beam is considered*. First a polarized electron beam line provides >1 mA of polarized electrons at ~120 MeV to a high-power target for positron production. Next, a second beam line collects, shapes and aligns the spin of positrons for users. Finally, the positron beam is matched into the CEBAF acceptance for acceleration and transport to the end stations with energies up to 12 GeV. An optimized layout to provide positrons beams with intensity >100 nA (polarized) or intensity >3 µA (unpolarized) will be discussed in this poster.
* D. Abbott et al., "Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies", Phys. Rev. Lett., 116, 214801 (2016)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK012

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 06 July 2022

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TUIZSP1

Status of the e⁺e⁻ Collider Projects in Asia and Europe: CEPC and FCC-ee

collider, cavity, booster, operation

815

X.C. Lou
IHEP, Beijing, People’s Republic of China
M. Boscolo
LNF-INFN, Frascati, Italy
F. Zimmermann
CERN, Meyrin, Switzerland

Since the Higgs boson discovery at CERN, precision measurement of its properties has become the first priority in the field of High Energy Physics. Two laboratories, CERN from Europe and IHEP from China, have proposed large scale circular electron-positron colliders, namely FCC-ee and CEPC. Record luminosities are expected in the center of mass energy range from 90 to about 365 GeV. In this talk the statuses of both projects are reviewed: Following the publication of the first CDR FCC-ee and CEPC entering the phase of consolidation and feasibility study. Special focus will be put on R&D plans, prototyping and key technologies.

Slides TUIZSP1 [6.718 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP1

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Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022

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WEOXGD3

An Alternative Design for BEPCII Upgrade

cavity, lattice, survey, emittance

1591

H. Geng, J. Xing, C.H. Yu, Y. Zhang
IHEP, Beijing, People’s Republic of China

The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high energy physics study. Along with the deepening of the research, more important physics is expected in higher energy region (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1 GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. The baseline design which kept the survey of the North Collision Region (NCR) unchanged for the upgrade of BEPCII has been studied in previous work. In this paper, we show an alternative design that modifies the survey of NCR, but enables the online maintenance of both RF cavities in each ring of BEPCII. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of BEPCII beam with reasonable margin.

Slides WEOXGD3 [3.761 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD3

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Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022

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WEPOST009

Muon Collider Based on Gamma Factory, FCC-ee and Plasma Target

plasma, electron, emittance, target

1691

F. Zimmermann, A. Latina
CERN, Meyrin, Switzerland
M. Antonelli, M. Boscolo
LNF-INFN, Frascati, Italy
A.P. Blondel
DPNC, Genève, Switzerland
J.P. Farmer
MPI-P, München, Germany

Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730 (iFAST).
The LEMMA-type muon collider generates muon pairs by the annihilation of 45 GeV positrons with electrons at rest. Due to the small cross section, an extremely high rate of positrons is required, which could be achieved by a ’Gamma factory’ based on the LHC. Other challenges with the LEMMA-type muon production scheme include the emittance preservation of muons and muon-generating positrons upon multiple traversals through a target, and the merging of many separate muon bunchlets. These two challenges may potentially be overcome by (1) operating the FCC-ee booster with a barrier bucket and induction acceleration, so that all positrons of a production cycle are merged into one single superbunch instead of storing ~10,000 separate bunches; and (2) sending the positron superbunch into a plasma target. During the passage of the positron superbunch, the electron density is enhanced 100–1000 fold without any increase in the density of nuclei, so that beamstrahlung and Coulomb scattering are essentially absent. We investigate prospects and difficulties of this approach, including emittance growth due to filamentation in the nonlinear plasma channel and due to positron self-modulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST009

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Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 05 July 2022

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WEPOST040

Comparing Methods of Recovering Gamma Energy Distributions from PEDRO Spectrometer Responses

photon, electron, site, scattering

1784

M.H. Oruganti, B. Naranjo, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, California, USA

To calculate the energy levels of the photons emitted from high-energy particle interactions, the new pair spectrometer (PEDRO) channels the photons through several Beryllium nuclear fields to produce electron-positron pairs through the nuclear field interaction. This project compared several methods of reconstruction and determined which best predicts original energy distributions based on simulated spectra. These methods included using Maximum Likelihood Estimation, Machine Learning, and directly analyzing a response matrix that modeled PEDRO’s response to any photon energy distribution. We report that performing the direct analysis, also known as QR decomposition, on a PEDRO-generated spectrum provides by far the most accurate calculation of the spectrum’s original energy distribution. These methods were tested against results from experimental cases, including Nonlinear Compton Scattering and Filamentation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST040

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

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WEPOPT017

First Optics Design for a Transverse Monochromatic Scheme for the Direct S-Channel Higgs Production at FCC-ee Collider

optics, collider, luminosity, site

1878

H.P. Jiang
Harbin Institute of Technology (HIT) , Harbin, People’s Republic of China
A. Faus-Golfe, Z.D. Zhang
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
K. Oide
KEK, Ibaraki, Japan
Z.D. Zhang
IHEP, Beijing, People’s Republic of China
Z.D. Zhang
UCAS, Beijing, People’s Republic of China
F. Zimmermann
CERN, Meyrin, Switzerland

The FCC-ee collider baseline foresees four different energy operation modes: Z, WW, H(ZH) and ttbar. An optional fifth mode, called s-channel Higgs production mode, could allow the measurement of the electron Yukawa coupling, in dedicated runs at 125 GeV centre-of-mass energy, provided that the centre-of-mass energy spread, can be reduced by at least an order of magnitude (5-10 MeV). The use of a special collision technique: a monochromatization scheme is one way to accomplish it. There are several methods to implement a monochromatization scheme. One method, named transverse monochromatization scheme, consists of introducing a dispersion different from zero but opposite sign for the two colliding beams at the Interaction Point (IP); In this paper we will report about the first attempt to design a new optics to implement a transverse monochromatic scheme for the FCC-ee Higgs production totally compatible with the standard mode of operation without dispersion at the IP.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT017

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022

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WEPOPT023

A Design of ILC E-Driven Positron Source

cavity, electron, linac, acceleration

1889

M. Kuriki, S. Konno, Z.J. Liptak
HU/AdSM, Higashi-Hiroshima, Japan
M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
H. Tajino
HU ADSE, Hiroshima, Japan
T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

ILC is an electron-positron linear collider based on Superconducting linear accelerator. Linear collider is an only solution to realinze high energy electron-positron collision beyond the limit of synchrotron radiation energy loss by ring colliders. Beam current of injector of linear colliders is much larger than that of ring colliders because the beam is not reusable. Providing an enough amount of particles, especially positron is a technical issue. In this article, we present a design of electron driven positron source for ILC. After optimizations, the system design is established with an enough technical margin, e.g. avoiding potential damage on the production target.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT023

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Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 23 June 2022

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WEPOPT024

Beam Loading Compensation of Standing Wave Linac with Off-Crest Acceleration

cavity, beam-loading, acceleration, klystron

1893

M. Kuriki, S. Konno, Z.J. Liptak
HU/AdSM, Higashi-Hiroshima, Japan
M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
H. Tajino
HU ADSE, Hiroshima, Japan
T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

In E-Driven positron source of ILC, the generated positron is captured by a standing wave cavity. Because the deceleration capture method is employed, the positron is off-crest over the linac. Because the beam-loading is expected to be more than 1A in a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation controlling the timing doesn’t work because RF and Beam induced field are in different phase. In this manuscript, we discuss the compensation with the off-crest acceleration case. A simple phase modulation on the input RF is a solution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT024

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Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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WEPOPT046

Preparation of a Prototype Plasma Lens as an Optical Matching Device for the ILC e⁺ Source

plasma, simulation, focusing, optical-matching

1961

M. Formela, N. Hamann, G.A. Moortgat-Pick
University of Hamburg, Hamburg, Germany
K. Flöttmann, G. Loisch, G.A. Moortgat-Pick
DESY, Hamburg, Germany

In recent years, high-gradient, symmetric focusing with active plasma lenses has regained significant interest due to the potential advantages in compactness and beam dynamics compared to conventional focusing elements. One potential application is the optical matching of highly divergent positrons from the undulator-based ILC positron source into the downstream accelerating structures. A collaboration between University Hamburg and DESY Hamburg has been established to develop a prototype design for this application. Here, we discuss beam dynamics simulation results, preliminary parameters of the lens prototype, and the current status of the prototype design.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT046

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Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 17 June 2022

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WEPOPT054

Target Studies for the FCC-ee Positron Source

target, radiation, electron, photon

1979

F. Alharthi, I. Chaikovska, R. Chehab, S. Ogur, A. Ushakov, S. Wallon
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
L. Bandiera, A. Mazzolari, M. Romagnoni, A.I. Sytov
INFN-Ferrara, Ferrara, Italy
J. Diefenbach, W. Lauth
IKP, Mainz, Germany
O. Khomyshyn
Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
D.M. Klekots
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
V.V. Mytrochenko
NSC/KIPT, Kharkov, Ukraine
P. Sievers, Y. Zhao
CERN, Meyrin, Switzerland
M. Soldani
Università degli Studi di Ferrara, Ferrara, Italy

FCC-ee injector study foresees 3.5~nC electron and positron bunches with 200 Hz repetition and 2 bunches per linac pulse at 6~GeV extraction energy. Regarding the possible options of positron production, we retain both of the conventional amorphous target and the hybrid target options. The hybrid scheme uses an intense photon production by 6 GeV electrons impinging on a crystal oriented along a lattice axis. In such a way, it involves two targets: a crystal as a photon radiator and an amorphous target-converter. Therefore, to avoid early failure or damage of the target, the candidate materials for the crystal and conversion targets have started to be tested by using the intense electron beam at Mainzer Mikrotron in Germany by the end of 2021. By manipulating the beam intensity, focusing, and chopping, a Peak Energy Deposition Density in the tested targets could be achieved close to that generated by the electron/photon beam in the FCC-ee positron target. Radiation-damage studies of the crystal sample have been also performed allowing estimating the effect on the photon enhancement used in the hybrid positron source.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT054

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Received ※ 16 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022

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WEPOPT062

Optimisation of the FCC-ee Positron Source Using a HTS Solenoid Matching Device

solenoid, target, linac, simulation

2003

Y. Zhao, S. Döbert, A. Latina, S. Ogur
CERN, Meyrin, Switzerland
B. Auchmann, P. Craievich, J. Kosse, R. Zennaro
PSI, Villigen PSI, Switzerland
I. Chaikovska, R. Chehab
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
M. Duda
IFJ-PAN, Kraków, Poland
P.V. Martyshkin
BINP SB RAS, Novosibirsk, Russia

In this paper, we present the simulation and optimisation of the FCC-ee positron source, where a high-temperature superconducting (HTS) solenoid is used as the matching device to collect positrons from the target. The "conventional" target scheme is used which simply consists of amorphous tungsten. The target is placed inside the bore of the HTS solenoid to improve the accepted positron yield at the entrance of the damping ring and the location of the target is optimised. The latest recommended baseline beam parameters are used and presented. An optimisation of the ideal positron yield using the analytic SC solenoid on-axis field is also performed and shows that the design of the HTS solenoid is optimal as far as the accepted positron yield is concerned.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT062

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022

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WEPOPT063

The FCCee Pre-Injector Complex

linac, electron, injection, collider

2007

P. Craievich, B. Auchmann, S. Bettoni, H.-H. Braun, M. Duda, D. Hauenstein, E. Hohmann, R. Ischebeck, P.N. Juranič, J. Kosse, G.L. Orlandi, M. Pedrozzi, J.-Y. Raguin, S. Reiche, S.T. Sanfilippo, M. Schaer, N. Vallis, R. Zennaro
PSI, Villigen PSI, Switzerland
F. Alharthi, I. Chaikovska, S. Ogur
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
W. Bartmann, M. Benedikt, M.I. Besana, M. Calviani, S. Döbert, Y. Dutheil, O. Etisken, J.L. Grenard, A. Grudiev, B. Humann, A. Latina, A. Lechner, K. Oide, A. Perillo-Marcone, H.W. Pommerenke, R.L. Ramjiawan, Y. Zhao, F. Zimmermann
CERN, Meyrin, Switzerland
A. De Santis
INFN/LNF, Frascati, Italy
Y. Enomoto, K. Furukawa, K. Oide
KEK, Ibaraki, Japan
O. Etisken
Kirikkale University, Kirikkale, Turkey
C. Milardi
LNF-INFN, Frascati, Italy
T.O. Raubenheimer
SLAC, Menlo Park, California, USA
N. Vallis
EPFL, Lausanne, Switzerland

The international FCC study group published in 2019 a Conceptual Design Report for an electron-positron collider with a centre-of-mass energy from 90 to 365 GeV with a beam currents of up to 1.4 A per beam. The high beam current of this collider create challenging requirements on the injection chain and all aspects of the linac need to be carefully reconsidered and revisited, including the injection time structure. The entire beam dynamics studies for the full linac, damping ring and transfer lines are major activities of the injector complex design. A key point is that any increase of positron production and capture efficiency reduces the cost and complexity of the driver linac, the heat and radiation load of the converter system, and increases the operational margin. In this paper we will give an overview of the status of the injector complex design and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration. In this framework, furthermore, we also present the preliminary studies of the FCC-ee positron source highlighting the main requirements and constraints.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT063

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Received ※ 11 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022

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THPOST003

Collective Effects Estimates for the Damping Ring Design of the FCC-ee

electron, emittance, impedance, damping

2435

O. Etisken
Ankara University, Faculty of Sciences, Ankara, Turkey
F. Antoniou, F. Zimmermann
CERN, Meyrin, Switzerland
A. De Santis
INFN/LNF, Frascati, Italy
C. Milardi
LNF-INFN, Frascati, Italy

The current injector complex design of the FCC-e⁺e⁻ project consists of e⁺/e⁻ linacs, which accelerate the beams up to 6 GeV, a damping ring at 1.54 GeV, a pre-booster ring, accelerating the beam up to 16 GeV and a booster synchrotron ring integrated in the collider tunnel accelerating the beams up to the collision energies. The purpose of the damping ring is to accept the 1.54 GeV beam coming from the linac-1, damp the positron/electron beams and provide the required beam characteristics for the injection into the linac-2. In this presentation the current damping ring design is introduced and analytical calculations on various collective effect such as space charge, intra-beam scattering, longitudinal micro-wave instability, transverse mode coupling instability, ion effects, electron cloud and coherent synchrotron radiation, are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST003

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022

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THPOST011

SuperKEKB Electron Positron Injector Linac Upgrade for Higher Charge and Lower Emittance

linac, emittance, electron, injection

2461

K. Furukawa, H. Ego, Y. Enomoto, N. Iida, T. Kamitani, M. Kawamura, S. Matsumoto, T. Matsumoto, T. Miura, M. Satoh, A. Shirakawa, T. Suwada, M. Yoshida
KEK, Ibaraki, Japan

KEK electron positron injector linac has established simultaneous top-up injections in 2019 for 5 rings of SuperKEKB DR, LER, HER, PF ring and PF-AR as a base of the both elementary particle physics and photon science experiments even under a quite short beam lifetime. It improved the injection stabilities while the SuperKEKB broke the world record of the collision luminosity of the previous project KEKB. As the collision performance improves, the beam-beam effect makes the dynamic aperture shrink, and the beam lifetime reduces further. Thus, it became inevitable for the injector to be upgraded in order to resolve the contradictory improvements of higher charge and lower emittance of injection beams regarding beam wakefield till 2025. The upgrade plan is described including pulsed magnets, an energy compression system, accelerating structures, girders, positron generator and so on.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST011

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Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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THPOST012

Achievement of 200, 000 Hours of Operation at KEK 7-GeV Electron 4-GeV Positron Injector Linac

injection, linac, operation, electron

2465

K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, Y. Enomoto, T. Higo, H. Honma, N. Iida, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, S. Matsumoto, T. Matsumoto, H. Matsushita, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, T. Natsui, Y. Ogawa, S. Ohsawa, Y. Okayasu, T. Oogoe, M.A. Rehman, I. Satake, M. Satoh, Y. Seimiya, T. Shidara, A. Shirakawa, H. Someya, T. Suwada, M. Tanaka, D. Wang, Y. Yano, K. Yokoyama, M. Yoshida, T. Yoshimoto, R. Zhang, X. Zhou
KEK, Ibaraki, Japan
Y. Bando
Sokendai, Ibaraki, Japan

KEK electron positron injector linac initiated the injection operation into Photon Factory (PF) light source in 1982. Since then for 39 years, it has served for multiple projects, namely, TRISTAN, PF-AR, KEKB, and SuperKEKB. Its total operation time has accumulated 200 thousand hours on May 7, 2020. We are extremely proud of the achievement following continuous efforts by our seniors. The construction of the injector linac started in 1978, and it was commissioned for PF with 2.5 GeV electron in 1982. In parallel, the positron generator linac was constructed for the TRISTAN collider project. The slow positron facility was also commissioned in 1992. After the KEKB asymmetric-energy collider project was commissioned in 1998 with direct energy injections, the techniques such as two-bunch acceleration and simultaneous injection were developed. As the soft structure design of the linac was too weak against the great east Japan earthquake, it took three years to recover. Then the construction and commissioning for the SuperKEKB project went on, and the simultaneous top-up injection into four storage rings contributes to the both elementary particle physics and photon science.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST012

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Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022

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THPOTK048

Radiation Load Studies for the FCC-ee Positron Source with a Superconducting Matching Device

target, collider, shielding, electron

2879

B. Humann
TU Vienna, Wien, Austria
B. Auchmann, J. Kosse
PSI, Villigen PSI, Switzerland
I. Chaikovska, S. Ogur
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
B. Humann, A. Latina, A. Lechner, Y. Zhao
CERN, Meyrin, Switzerland

For an electron-positron collider like FCC-ee, the production of positrons plays a crucial role. One of the design options considered for the FCC-ee positron source employs a superconducting solenoid made of HTS coils as an adiabatic matching device. The solenoid, which is placed around the production target, is needed to capture positrons before they can be accelerated in a linear accelerator. A superconducting solenoid yields a higher peak field than a conventional-normal conducting magnetic flux concentrator, therefore increasing the achievable positron yield. In order to achieve an acceptable positron production, the considered target is made of tungsten-rhenium, which gives also a significant flux of un-wanted secondary particles, that in turn could generate a too large radiation load on the superconducting coils. In this study, we assess the feasibility of such a positron source by studying the heat load and long-term radiation damage in the superconducting matching device and surrounding structures. Results are presented for different geometric configurations of the superconducting matching device.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK048

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 07 July 2022

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