IPAC2021 - List of Keywords (photon)

Paper	Title	Other Keywords	Page
MOXA02	Status of the APS-U Project	emittance, lattice, injection, storage-ring	7
	R.O. Hettel ANL, Lemont, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Sci- ence, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357. The Advanced Photon Source Upgrade (APS-U) project at the Argonne National Laboratory will re-place the existing 7-GeV, 1.1-km circumference dou-ble bend storage ring lattice with a new 6-GeV hybrid 7BA lattice that will reduce horizontal electron emit-tance from 3 nm-rad to 42 pm-rad, including IBS ef-fects for 200-mA operation. With new optimized per-manent magnet and superconducting undulators, an increase in spectral brightness of two to three orders of magnitude in the 10-100 keV X-ray energy range will be realized. The project includes nine new high performance beamlines and fifteen enhanced beam-lines that will exploit the high brightness and coher-ence of the new facility. The project is in full swing, more than 50% complete by cost, and is on schedule for first beam sometime in mid-2024, a slip of 10 months from the original schedule due to the impact of COVID-19. Project status, challenges and outstanding issues will be discussed in this article.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXA02
About •	paper received ※ 21 May 2021 paper accepted ※ 09 June 2021 issue date ※ 11 August 2021
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MOPAB018	SASE Gain-Curve Measurements with MCP-Based Detectors at the European XFEL	FEL, detector, undulator, radiation	96
	E. Syresin, O.I. Brovko, A.Yu. Grebentsov JINR, Dubna, Moscow Region, Russia W. Freund, J. Grünert, J. Liu, Th. Maltezopoulos, D. Mamchyk EuXFEL, Schenefeld, Germany M.V. Yurkov DESY, Hamburg, Germany
	Radiation detectors based on microchannel plates (MCP) are used for characterization of the Free-Electron Laser (FEL) radiation and measurements of the Self-amplified spontaneous emission (SASE) gain curve at the European XFEL. Photon pulse energies are measured by the MCPs with an anode and by a photodiode. There is one MCP-based detector unit installed in each of the three photon beamlines downstream of the SASE1, SASE2, and SASE3 undulators. MCP detectors operate in a wide dynamic range of pulse energies, from the level of spontaneous emission up to FEL saturation. Their wavelength operation range overlaps with the whole range of radiation wavelengths of SASE1 and SASE2 (from 0.05 nm to 0.4 nm), and SASE3 (from 0.4 nm to 5 nm). In this paper we present results of SASE gain-curve measurements by the MCP-based detectors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB018
About •	paper received ※ 18 May 2021 paper accepted ※ 17 August 2021 issue date ※ 23 August 2021
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MOPAB042	Beam Dynamics Investigation for a New Project of Compton Back Scattering Photon Source at NRNU MEPhI	linac, electron, scattering, laser	186
	V.S. Dyubkov, I.A. Ashanin, M. Gusarova, Yu.D. Kliuchevskaia, M.V. Lalayan, S.M. Polozov, A.I. Pronikov, V.I. Rashchikov MEPhI, Moscow, Russia
	Funding: This project is supported by Russian Foundation for Basic Research, Grant no. 19-29-12036. The activities on physical models design of a compact monochromatic radiation source in the x-ray range based on inverse Compton scattering are started at NRNU MEPhI. There are comparison of two schemes of the photon source here: one of them is considered to be based on linac with variable energy of 20-60 MeV only and the other one is considered as accelerator complex where linac is supposed to be used as injector to medium size storage ring (energy up to 60 MeV). Preliminary results of linac structures and storage ring design as well as electron dynamics simulation are discussed
	Poster MOPAB042 [0.962 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB042
About •	paper received ※ 13 May 2021 paper accepted ※ 20 May 2021 issue date ※ 10 August 2021
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MOPAB044	Gas Bremsstrahlung Measurements in the Advanced Photon Source Storage Ring	radiation, operation, detector, injection	193
	J.C. Dooling, A.R. Brill, J.R. Calvey ANL, Lemont, Illinois, USA
	Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357. In the Advanced Photon Source Upgrade storage ring (SR), small-aperture vacuum chambers provide limited conductance for pumping. Non-evaporable getter (NEG) coatings will be used in the SR to support the vacuum. Ion pumps and cold-cathode gauges are typically located away from the vacuum chamber transporting the beam. Measuring gas bremsstrahlung (GB) photons in low-conductance chambers provides a method to determine the pressure at the beam location. We report on GB measurements made in the ID-25 beamline. A Pb:Glass calorimeter radiator generates Cherenkov radiation when high-energy photons cause pair-production within the glass. A photomultiplier tube converts the light pulses to electrical signals. Data was obtained during normal machine operations starting in January 2020. Data collection was facilitated using a 4-channel ITech Beam Loss Monitor FPGA that allows for control of thresholds and attenuation settings in both counting and pulse-height acquisition modes. Count rates and spectra were recorded for the three primary fill patterns typically used during SR operations as well as during gas injection experiments; results of these measurements will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB044
About •	paper received ※ 22 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021
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MOPAB055	Generation of Coherent Attosecond X-ray Pulses in the Southern Advanced Photon Source	laser, electron, storage-ring, emittance	237
	W. Liu, Y. Zhao IHEP CSNS, Guangdong Province, People’s Republic of China Y. Jiao, S. Wang IHEP, Beijing, People’s Republic of China
	Southern Advanced Photon Source (SAPS) is a fourth-generation storage ring light source that has been considered for construction in Guangdong province of China, adjacent to the China Spallation Neutron Source. As a low-emittance storage ring, the natural emittance of SAPS is below 100 pm. One of the benefits is that the brightness is about 2 orders high than 3rd generation light sources. However, like many other storage ring-based light sources, the time resolution is limited by the electron bunch length in the range of picoseconds. In this work, we propose a new scheme for the generation of coherent attoseconds X-ray pulses with a high repetition rate in SAPS. A numerical demonstration of the scheme is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB055
About •	paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 26 August 2021
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MOPAB058	Swap-Out Safety Tracking for the Advanced Photon Source Upgrade	dipole, simulation, electron, power-supply	249
	M. Borland, J.S. Downey, M.S. Jaski ANL, Lemont, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The Advanced Photon Source upgrade will operate in swap-out mode, which is similar to top-up but involves complete replacement of individual depleted bunches in a single shot. As with top-up, safety is a concern given that this process will take place with beamline shutters open. We describe the methods used to model swap-out safety, including creation and validation of a full ring lattice based on 3D field maps. We also describe a new method of implementing complex, intersecting channels for electron beams and photon beams, as well as a method of easily identifying potentially dangerous stray particles. Numerous potential errors (e.g., magnet shorts) were modeled, giving a reliable indication of performance of proposed stored beam and magnet interlocks.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB058
About •	paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 29 August 2021
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MOPAB073	Beam Loss Simulations During Beam Dumping in Heps	kicker, lattice, simulation, dumping	294
	X. Cui, Y. Jiao, Y.L. Zhao IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is a 6 GeV storage ring light source under construction in China. Several collimators installed in the vacuum chamber will be used as beam dump in the storage ring operation. Preliminary simulations showed that the temperature rise caused by the beam power deposited on the collimators will far exceed the melting point of the collimator material. In order to cure this problem, special kickers are proposed to be installed in the ring to modulate the beam during beam dumping, thereby increasing the size of the beam hit on the collimators. In this article, some simulation results of the density of particles on the collimators during beam dumping for different HEPS lattice and different kicker parameters are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB073
About •	paper received ※ 17 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021
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MOPAB075	Proposal of the Southern Advanced Photon Source and Current Physics Design Study	linac, storage-ring, lattice, emittance	300
	S. Wang, J. Chen, L. Huang, Y. Jiao, B. Li, Z.P. Li, W. Liu, S.Y. Xu IHEP, Beijing, People’s Republic of China Y. Han, X.H. Lu, Y. Zhao IHEP CSNS, Guangdong Province, People’s Republic of China X. Liu Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
	It has been considered to build a mid-energy fourth-generation storage ring light source neighbouring the China Spallation Neutron Source, in Guangdong Province, the south of China. The light source is named the Southern Advanced Photon Source (SAPS). Preliminary physics design studies on the SAPS have been implemented for a few years. In this paper, we will describe considerations of technical roadmap and key parameter choice for this light source, and introduce the up-to-date lattice designs and related physics studies on the SAPS.
	Poster MOPAB075 [1.689 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB075
About •	paper received ※ 12 May 2021 paper accepted ※ 20 May 2021 issue date ※ 21 August 2021
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MOPAB084	Acceptance Tests and Installation of the IVU and Front End for the XAIRA Beamline of ALBA	undulator, vacuum, experiment, insertion	318
	J. Campmany, J. Marcos, V. Massana ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	XAIRA is a new beamline being built at ALBA synchrotron for macromolecular crystallography (MX) devoted to the study of small bio crystals. It aims at providing a full beam with a size of 3x1 µm² FWHM (hxv) and flux of >3·10¹² ph/s (250 mA in Storage Ring) at 1 Å wavelength (12.4 keV) to tackle MX projects for which only tiny (<10 μm) or imperfect crystals are obtained. Besides, XAIRA aims at providing photons at low energies, down to 4 keV, to support MX experiments exploiting the anomalous signal of the metals naturally occurring in proteins (native phasing), which is enhanced in the case of small crystals and long wavelengths. To this end, an in-vacuum undulator has been built by a consortium between Kyma and Research Instruments companies. In this paper, we present the results of the Site Acceptance Tests made at ALBA using a new bench developed to measure closed structures, and also the steps done for its installation in the ALBA tunnel.
	Poster MOPAB084 [1.715 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB084
About •	paper received ※ 11 May 2021 paper accepted ※ 20 May 2021 issue date ※ 25 August 2021
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MOPAB085	Design and Fabrication of a Short Multipole Wiggler and the Front End for the New ALBA Beamline FAXTOR	wiggler, vacuum, insertion, insertion-device	321
	J. Campmany, J. Marcos, V. Massana ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	FAXTOR is a new hard XR tomography beam line that is being built at ALBA in order to fulfil the needs that cannot be currently covered by the MISTRAL VUV and soft XR beamline. This beam line needs a small source size as well higher than 10¹² Photons per second through an aperture of 4x1 mm2 in the whole range 5 to 60 keV, for a current of 250 mA in Storage Ring with source size maintained below 310 µm horizontal and 25 µm vertical. The contract was awarded to AVS-US Company. In this paper we present the design finally selected as well as the preliminary design carried out by manufacturer to implement the conceptual model designed by ALBA.
	Poster MOPAB085 [1.879 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB085
About •	paper received ※ 11 May 2021 paper accepted ※ 20 May 2021 issue date ※ 31 August 2021
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MOPAB086	Design of Front End and a 3-Pole-Wiggler as a Photon Source for BEATS Beamline at SESAME	wiggler, vacuum, synchrotron, insertion	324
	J. Campmany, J. Marcos ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain M. Al Nadjawi, M. Attal, G. Lori SESAME, Allan, Jordan I. Cudin Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy S. Guiducci INFN/LNF, Frascati, Italy P. Van Vaerenbergh ESRF, Grenoble, France
	BEATS is an international collaboration funded by EU in order to design and implement an XR tomography beam line in SESAME Jordanian synchrotron. ALBA contribution consists in the design of the photon source and the Front End elements. In this paper we present the conceptual designs of both the 3-pole wiggler uses as photon source as well as the Front End elements designed for the beamline.
	Poster MOPAB086 [2.306 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB086
About •	paper received ※ 11 May 2021 paper accepted ※ 21 May 2021 issue date ※ 17 August 2021
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MOPAB090	Status of HEPS Insertion Devices Design	undulator, radiation, wiggler, insertion	339
	X.Y. Li, Y. Jiao, H.H. Lu, S.K. Tian IHEP, Beijing, People’s Republic of China
	HEPS is a 4th generation light source with the energy of 6 GeV and ultralow emittance of 34 pm.rad. A total of 14 beamlines with 19 insertion devices has been planned in the first phase, including 6 cryogenic undulators, 5 in-vacuum undulators, and two special non-planar IDs. The schemes and parameters of all the IDs are planned to be determined in this year. We report on the status of the design of these IDs and their effects on beam dynamics.
	Poster MOPAB090 [0.633 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB090
About •	paper received ※ 13 May 2021 paper accepted ※ 01 July 2021 issue date ※ 10 August 2021
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MOPAB096	Rocking Curve Imaging Experiment at SSRL 10-2 Beamline	wiggler, experiment, radiation, lattice	357
	A. Halavanau, R. Arthur, B. Johnson, J.P. MacArthur, G. Marcus, R.A. Margraf, Z. Qu, T. Rabedeau, T. Sato, C.J. Takacs, D. Zhu SLAC, Menlo Park, California, USA
	Stanford Synchrotron Radiation Lightsource (SSRL) serves a wide scientific community with its variety of X-ray capabilities. Recently, we have employed a wiggler source located at beamline 10-2 to perform high resolution rocking curve imaging (RCI) of diamond and silicon crystals. In-house X-ray RCI capability is important for the upcoming cavity-based x-ray source development projects at SLAC, such as cavity-based XFEL (CBXFEL) and X-ray laser oscillator (XLO). In this proceeding, we describe theoretical considerations, and provide experimental results, validating the design of our apparatus. We also provide a plan for future improvements of the RCI@SSRL program.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB096
About •	paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 10 August 2021
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MOPAB097	Two Color Grating design for Soft X-Ray Self-Seeding at LCLS-II	FEL, electron, simulation, laser	361
	A. Halavanau, D. Cocco, E. Hemsing, G. Marcus, D.S. Morton SLAC, Menlo Park, California, USA G.R. Wilcox Cornell University, Ithaca, New York, USA
	A new grating design is examined for the soft x-ray self-seeding system (SXRSS) at LCLS-II to ultimately produce stable two-color XFEL pulses. The grating performance is analyzed with Fourier optics methods. The final XFEL performance is assessed via full numerical XFEL simulations that substantiate the feasibility of the proposed design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB097
About •	paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 21 August 2021
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MOPAB120	Update on Injector for the New Synchrotron Light Source in Thailand	linac, storage-ring, synchrotron, injection	435
	T. Chanwattana, S. Chunjarean, N. Juntong, K. Kittimanapun, S. Klinkhieo, P. Sudmuang SLRI, Nakhon Ratchasima, Thailand K. Manasatitpong Synchrotron Light Research Institute (SLRI), Muang District, Thailand
	Design of the new 3-GeV synchrotron light source in Thailand, Siam Photon Source II (SPS-II), has been updated. The SPS-II accelerator complex consists of a 150-MeV injector linac, a 3-GeV booster synchrotron and a 3-GeV storage ring. The RF system of both storage ring and booster is based on a frequency of 119 MHz. In this paper, design considerations and specifications of the SPS-II injector linac are presented. A study on the injector linac in multi-bunch mode (MBM) and single-bunch mode (SBM) was done to get appropriate parameters for top-up injection and different filling patterns in the storage ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB120
About •	paper received ※ 18 May 2021 paper accepted ※ 20 May 2021 issue date ※ 24 August 2021
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MOPAB126	BESSY III & MLS II - Status of the Development of the New Photon Science Facility in Berlin	undulator, radiation, lattice, emittance	451
	P. Goslawski, M. Abo-Bakr, F. Andreas, M. Arlandoo, J. Bengtsson, V. Dürr, K. Holldack, J.-G. Hwang, A. Jankowiak, B.C. Kuske, J. Li, A.N. Matveenko, T. Mertens, A. Meseck, E.C.M. Rial, M. Ries, M.K. Sauerborn, A. Schälicke, M. Scheer, P. Schnizer, L. Shi, J. Viefhaus HZB, Berlin, Germany J. Lüning UPMC, Paris, France
	HZB operates and develops two synchrotron radiation sources at Berlin Adlershof. The larger one, BESSY II with an energy of 1.7 GeV and 240 m circumference is optimized for soft-X rays and in operation since 1999. The smaller one is the MLS (Metrology Light Source), owned by the Physikalische Technische Bundesanstalt (PTB) - Germany’s National Metrology Institute. It is designed to fulfill the special metrology needs of the PTB with an energy of 0.6 GeV and 48 m circumference, covering the spectral range from THz and IR to EUV/VUV. In 2020 a discussion process has been started to define the requirements for successors of BESSY II and MLS and to study the possibilities integrate them into a new photon science facility in Berlin Adlershof. Here, we give a status report and present a first envisaged parameter space to both machines (see also MOPAB262, MOPAB220, MOPAB048, MOPAB242).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB126
About •	paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 18 August 2021
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MOPAB131	Synchrotron SOLEIL Upgrade Project	lattice, emittance, vacuum, injection	463
	A. Nadji SOLEIL, Gif-sur-Yvette, France
	To remain competitive in the future, SOLEIL is also working on an upgrade project plan based on Multi-Bend Achromat (MBA) lattices. The Technical Design Report of the project is expected to start in early 2021 immediately after the completion of the Conceptual Design Report (CDR) phase. The achieved equilibrium emittance in the CDR reference lattice (80 pm-rad) is about 50 times smaller than that of the existing storage ring (4000 pm-rad). By operating on a linear coupling resonance, round beam sizes in Insertion Devices straight sections of less than 10 microns RMS in both planes can be produced. These performances rely on the use of a 10 mm inner diameter circular copper vacuum chamber with NEG-coating allowing reaching strong quadrupole gradients and very strong sextupole and octupole strengths. As all these technical challenges are pushing the engineering technology to the limits, they are being investigated through an intensive R&D program based on extensive numerical simulations, prototyping, and measurement with the beam. Extensive use of the pure permanent magnet technology beyond what has been done so far in the other similar projects is considered in this project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB131
About •	paper received ※ 22 May 2021 paper accepted ※ 27 July 2021 issue date ※ 30 August 2021
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MOPAB240	Estimates of Damped Equilibrium Energy Spread and Emittance in a Dual Energy Storage Ring	emittance, storage-ring, damping, radiation	774
	B. Dhital, G.A. Krafft ODU, Norfolk, Virginia, USA Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, and Office of Nuclear Physics under Contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. / Jefferson Lab EIC Fellowship2020. A dual energy storage ring design consists of two loops at markedly different energies. As in a single-energy storage ring, the linear optics in the ring design may be used to determine the damped equilibrium emittance and energy spread. Because the individual radiation events in the two rings are different and independent, we can provide analytical estimates of the damping times in a dual energy storage ring. Using the damping times, the values of damped energy spread, and emittance can be determined for a range of parameters related to lattice design and rings energies. We present analytical calculations along with simulation results to estimate the values of damped energy spread and emittance in a dual energy storage ring. We note that the damping time tends to be dominated by the damping time of the high energy ring in cases where the energy of the high energy rings is significantly greater than that of the low energy ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB240
About •	paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 13 August 2021
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MOPAB279	Non-Invasive Beam Profile Monitoring for the HL-LHC Hollow Electron Lens	electron, proton, background, luminosity	884
	A. Salehilashkajani, N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom M. Ady, N.S. Chritin, N. Jens, O.R. Jones, R. Kersevan, T. Lefèvre, S. Mazzoni, G. Papazoglou, A. Rossi, G. Schneider, R. Veness CERN, Geneva, Switzerland P. Forck, S. Udrea GSI, Darmstadt, Germany N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work was supported by the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1 and the STFC Cockcroft core grant No. ST/G008248/1. A Hollow Electron Lens (HEL) is currently under development for the High-Luminosity upgrade of the Large Hadron Collider (HL-LHC). In this device, a hollow electron beam co-propagates with a central proton beam and provides active halo control in the LHC. To ensure the concentricity of the two beams, a non-invasive diagnostic instrument is currently being commissioned. This instrument is a compact version of an existing prototype that leverages beam induced fluorescence with supersonic gas curtain technology. This contribution includes the design features of this version of the monitor, recent progress, and future plans for tests at the Cockcroft Institute and the electron lens test stand at CERN.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB279
About •	paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 02 September 2021
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MOPAB296	Statistical Analysis of 2D Single-Shot PPRE Bunch Measurements	radiation, operation, diagnostics, storage-ring	939
	M. Koopmans, J.-G. Hwang, A. Jankowiak, M. Ries, A. Schälicke, G. Schiwietz HZB, Berlin, Germany
	The pulse picking by resonant excitation (PPRE) method* is used to realize pseudo single-bunch radiation from a complex filling pattern at the BESSY II storage ring. The PPRE bunch is excited in the horizontal plane by a quasi-resonant incoherent perturbation to increase the emittance of this bunch. Therefore, the synchrotron light of the PPRE bunch can be separated by collimation from the radiation of the main bunch train at dedicated beamlines for timing users. The properties of the PPRE bunch depend on the storage ring settings and on the excitation parameters. It is not trivial to distinguish between the wanted intrinsic bunch broadening and an additional position fluctuation of the PPRE bunch. Using the potential of the new diagnostics beamline with the possibility to observe an additional spatial dimension with a fast streak camera, we introduce a new method to study the properties of the PPRE bunch. Applying a statistical analysis to a series of single-turn images enables distinguishing between horizontal orbit motion and the broadening of the bunch due to the excitation. Measurements are presented and the results are compared with data from the BPM system. K. Holldack et al., Nature Commun. 5 (2014) 4010. J.-G. Hwang et al., Nucl. Instrum. Methods A940 (2019) 387. * G. Schiwietz et al., Nucl. Instrum. Methods A990 (2021) 164992.
	Poster MOPAB296 [2.074 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB296
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 23 August 2021
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MOPAB303	Design of the X-Ray Beam Size Monitor for the Advanced Photon Source Upgrade	emittance, electron, detector, storage-ring	956
	K.P. Wootton, F.K. Anthony, K. Belcher, J.S. Budz, J. Carwardine, W.X. Cheng, S. Chitra, G. Decker, S.J. Izzo, S.H. Lee, J. Lenner, Z. Liu, P. McNamara, H.V. Nguyen, F.S. Rafael, C. Roehrig, J. Runchey, N. Sereno, G. Shen, J.B. Stevens, B.X. Yang ANL, Lemont, Illinois, USA
	Funding: This research used resources of the Advanced Photon Source, operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. A beam size monitor provides an intuitive display of the status of the beam profile and motion in an accelerator. In the present work, we outline the design of the X-ray electron beam size monitor for the Advanced Photon Source Upgrade. Components and anticipated performance characteristics of the beam size monitor are outlined.
	Poster MOPAB303 [0.577 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB303
About •	paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 24 August 2021
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MOPAB328	Beam Instrumentation for Linear Accelerator of SKIF Synchrotron Light Source	electron, diagnostics, radiation, simulation	1016
	X.C. Ma BINP, Novosibirsk, Russia M.V. Arsentyeva, E.A. Bekhtenev, V.M. Borin, G.V. Karpov, Yu.I. Maltseva, O.I. Meshkov, D.A. Nikiforov, O.A. Pavlov, V.G. Tcheskidov, V. Volkov BINP SB RAS, Novosibirsk, Russia M.V. Arsentyeva, E.A. Bekhtenev, V.M. Borin, Yu.I. Maltseva, O.I. Meshkov, D.A. Nikiforov NSU, Novosibirsk, Russia V.M. Borin NSTU, Novosibirsk, Russia
	A new synchrotron light source SKIF of the 4th generation is under construction at BINP SB RAS (Novosibirsk, Russia). The linear accelerator is SKIF’s injector to provide 200 MeV electron beam. The set of diagnostics will be applied for tuning of the linear accelerator and measurements of beam parameters from electron RF gun to output of the accelerator. It includes 8 fluorescent screens for the beam transverse dimensions measurement, 2 Cherenkov probes for the beam duration measurement, magnetic spectrometer with range from 0.6 to 200 MeV, and some beam charge and current measurement devices, as Faraday cup, FCT, BPM along linear accelerator. Numerical simulations of diagnostics elements and results of beam dynamics simulations are introduced in paper. Brief description of the design and parameters of each diagnostics system is presented. Possible scenarios of linear accelerator tuning are also discussed.
	Poster MOPAB328 [2.324 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB328
About •	paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 31 August 2021
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MOPAB380	Status and Progress of the RF System for High Energy Photon Source	cavity, storage-ring, booster, low-level-rf	1165
	P. Zhang, J. Dai, Z.W. Deng, L. Guo, T.M. Huang, D.B. Li, J. Li, Z.Q. Li, H.Y. Lin, Y.L. Luo, Q. Ma, F. Meng, Z.H. Mi, Q.Y. Wang, X.Y. Zhang, F.C. Zhao, H.J. Zheng IHEP, Beijing, People’s Republic of China
	Funding: This work was supported in part by High Energy Photon Source, a major national science and technology infrastructure in China and in part by the Chinese Academy of Sciences. High Energy Photon Source (HEPS) is a 6 GeV diffraction-limited synchrotron light source currently under construction in Beijing. It adopts a double-frequency RF system with 166.6 MHz as fundamental and 499.8 MHz as third harmonic. The fundamental cavity is making use of a superconducting quarter-wave β=1 structure and the third harmonic is of superconducting elliptical single-cell geometry for the storage ring, while normal-conducting 5-cell cavities are chosen for the booster ring. A total of 900 kW RF power shall be delivered to the beam by the 166.6 MHz cavities and the third harmonic cavities are active. All cavities are driven by solid-state power amplifiers and the RF fields are regulated by digital low-level RF control systems. The cavity and ancillaries, high-power RF system and low-level RF control system are in the prototyping phase. This paper presents the current status and progress of the RF system for HEPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB380
About •	paper received ※ 09 May 2021 paper accepted ※ 09 June 2021 issue date ※ 24 August 2021
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MOPAB390	Development of a 166.6 MHz Low-Level RF System by Direct Sampling for High Energy Photon Source	cavity, LLRF, controls, pick-up	1189
	D.B. Li, H.Y. Lin, Q.Y. Wang, P. Zhang IHEP, Beijing, People’s Republic of China
	Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China. A digital low-level radio frequency (LLRF) system by direct sampling has been proposed for 166.6 MHz superconducting cavities at High Energy Photon Source (HEPS). The RF field inside the cavities has to be controlled better than ±0.1% (peak to peak) in amplitude and ±0.1 deg (peak to peak) in phase. Considering that the RF frequency is 166.6 MHz, which is well within the analog bandwidth of modern high-speed ADCs and DACs, direct RF sampling and direct digital modulation can be achieved. A digital LLRF system utilizing direct sampling has therefore been developed with embedded experimental physics and industrial control system (EPICS) in the field programmable gate array (FPGA). The performance in the lab has been characterized in a self-closed loop with a residual peak-to-peak noise of ±0.05% in amplitude and ±0.03 deg in phase, which is well below the HEPS specifications. Further tests on a warm 166.6 MHz cavity in the lab are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB390
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021
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MOPAB405	Study of Targets to Produce Molybdenum-99 Using 30 MeV Electron Linear Accelerator	target, electron, radiation, linac	1222
	T.S. Dixit, A.P. Deshpande, R. Krishnan, A. Shaikh SAMEER, Mumbai, India
	Funding: Ministry of Electronics and Information Technology, Government of India (MeitY) Two approaches to produce 99Mo are studied using GEANT4 are reported in this paper. First, in converter target approach, bremsstrahlung photons are generated in a high Z target. The emitted photons then hit 100Mo secondary target, producing 99Mo through (gamma, n) reaction. Second, in direct target approach, high energy electron beam hits 100Mo target, where both (e, gamma) and (gamma, n) reactions take place simultaneously. A 30 MeV, 5-10 kW beam power electron linac is under development at SAMEER. The acceleration gradient required to achieve 30 MeV energy will be provided by two linacs operated in series configuration and the high average beam power will be achieved by running the system at high duty operation. Main aim of this study is to optimize experimental parameters to maximize specific activity of 99Mo. Since, 100Mo is very expensive material therefore judicious use of the material is very important. Hence, optimization of electron beam energy and target dimensions are studied in detail in both the approaches. It is found that the direct target approach gives higher specific activity compared to the converter target approach.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB405
About •	paper received ※ 19 May 2021 paper accepted ※ 06 June 2021 issue date ※ 14 August 2021
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MOPAB409	FLUKA Simulations of ²²⁵Ac Production Using Electron Accelerators: Validation Through Comparison with Published Experiments	electron, experiment, target, radiation	1226
	T.V. Szabo, I.C. Moraes CNPEM, Campinas, SP, Brazil F.A. Bacchim Neto LNLS, Campinas, Brazil P.V. Guillaumon USP/LAL, Sao Paulo, Brazil H.B. de Oliveira IPEN, São Paulo, Brazil
	Targeted Alpha Therapy (TAT) is an active area of study worldwide. This technique has shown a potential in nuclear medicine to treat metastatic disease by alpha particles that deposit energy in small regions nearby cancer cells. Ac-225 is an important alpha-emitting that can be used for cancer TAT. This radioisotope shows good potential for medical applications, therefore is important to study ways of increase its production and availability. One possible path for the Ac-225 product is to radiate a radium target (Ra-226) on a linear electron accelerator (LINAC). Isotope production studies could be implemented using computational tools. In this work, Monte Carlo simulations with FLUKA code were performed and compared to experimental results . We studied Ac-225 production by photonuclear reactions using a 24 MeV electron beam LINAC hitting a tungsten electron-photon converter. Different energies and geometries were also simulated to obtain optimal production conditions. The specific activity values obtained with simulations had a good agreement with published experimental results. MASLOV, O., et. al. Preparation of 225Ac by 226Ra(g, n) photonuclear reaction on an mt25 microtron. Radiochemistry
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB409
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021
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TUPAB027	Review of Accelerator Limitations and Routes to Ultimate Beams	collider, acceleration, electron, luminosity	1397
	F. Zimmermann CERN, Geneva, Switzerland R.W. Aßmann DESY, Hamburg, Germany M. Bai, G. Franchetti GSI, Darmstadt, Germany
	Funding: This work was supported in part by the European Commission under the HORIZON 2020 project I.FAST, no. 101004730. Various physical and technology-dependent limits are encountered for key performance parameters of accelerators such as high-gradient acceleration, high-field bending, beam size, beam brightness, beam intensity and luminosity. This paper will review these limits and the associated challenges. Possible figures-of-merit and pathways to ultimate colliders will also be explored.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB027
About •	paper received ※ 16 May 2021 paper accepted ※ 02 August 2021 issue date ※ 23 August 2021
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TUPAB046	Preliminary design of the Full Energy Linac Injector for the Southern Advanced Photon Source	linac, FEL, gun, injection	1454
	X. Liu Institute of High Energy Physics, CAS, Guangdong, People’s Republic of China Y. Jiao, B. Li, S. Wang IHEP, Beijing, People’s Republic of China
	A 4th generation mid-energy range diffraction limited storage ring, named as the Southern Advanced Photon Source (SAPS), is under consideration to be built at the same campus as China Spallation Neutron Source (CSNS), providing a charming one-stop solution for fundamental sciences and industrial applications. While the design of the ring is still under study, a full energy Linac has been proposed as one candidate option for its injector, with the capability of being used as an X-ray Free Electron Laser (XFEL) in the near future. In this paper, an overview of the preliminary design of the Linac is given and simulation results are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB046
About •	paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 10 August 2021
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TUPAB052	Current Study of Applying Machine Learning to Accelerator Physics at IHEP	network, electron, lattice, target	1477
	J. Wan, Y. Jiao IHEP, Beijing, People’s Republic of China
	Funding: National Natural Science Foundation of China(No.11922512), Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y201904) and National Key R&D Program of China(No.2016YFA0401900). In recent years, machine learning (ML) has attracted increasing interest among the accelerator field. As a complex collection of multiple physical subsystems, the design and operation of an accelerator can be very nonlinear and complicated, while ML is taken as a powerful tool to solve such nonlinear and complicated problems. In this study, we report on several successful applications of ML to accelerator physics at IHEP. The nonlinear dynamics optimization of the High Energy Photon Source (HEPS) that is a 4th-generation light source is a challenging topic. In this optimization, we use a ML surrogate model to fast select the potentially competitive solutions for a multiobjective genetic algorithm that can significantly improve the convergence rate and the diversity among obtained solutions. Besides, we also tried to apply a generative adversarial net to solve one-to-many problems of longitudinal beam current profile shaping. Unlike most supervised machine learning methods than cannot learn one-to-many maps, the generative adversarial net-based method is able to predict multiple solutions instead of one for a 4-dipole chicane to realize several desired custom current profiles.
	Poster TUPAB052 [0.913 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB052
About •	paper received ※ 11 May 2021 paper accepted ※ 21 June 2021 issue date ※ 27 August 2021
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TUPAB054	CDR BASELINE LATTICE FOR THE UPGRADE OF SOLEIL	lattice, emittance, injection, coupling	1485
	A. Loulergue, D. Amorim, P. Brunelle, A. Gamelin, A. Nadji, L.S. Nadolski, R. Nagaoka, R. Ollier, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Previous MBA studies converged toward a lattice composed of 20 7BA solution elaborated by adopting the sextupole pairing scheme with dispersion bumps originally developed at the ESRF-EBS. It provided a low natural horizontal emittance value of 70-80 pm-rad range at an energy of 2.75 GeV. Due to difficulties to accommodate such lattice geometry in the SOLEIL present tunnel as well as to preserve at best the beamline positioning, alternative lattice based on HOA (Higher-Order Achromat) type cell has been recently investigated. The HOA type cell being more modular and possibly exhibiting larger momentum acceptance as well as low emittances, a solution alternating 7BA and 4BA cells was then identified as the best to adapt the current beamline positioning. The SOLEIL CDR upgrade reference lattice is then composed of 20 HOA cells alternating 7BA and 4BA giving a natural horizontal emittance of 80 pm-rad. The linear and non-linear beam dynamic properties of the lattice along with the possibility of horizontal off-axis injection at full betatron coupling are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB054
About •	paper received ※ 21 May 2021 paper accepted ※ 02 July 2021 issue date ※ 10 August 2021
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TUPAB058	Online Optimizations of Several Observable Parameters at the Advanced Photon Source	injection, storage-ring, kicker, sextupole	1492
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Online optimizations are known to be powerful tools which may quickly and efficiently improve the particle accelerator key performance parameters in a model-independent way. In this paper, it is presented on the online optimizations of several observable parameters at the Advanced Photon Source storage ring. These observable parameters include the beam lifetime, injection efficiency and topup efficiency, transverse beam sizes, and turn by turn beam position monitors. It is demonstrated that the particle accelerator performance may be greatly enhanced in a relatively short time frame, by optimizing these observable parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB058
About •	paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 16 August 2021
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TUPAB060	Machine Learning on Beam Lifetime and Top-Up Efficiency	network, operation, storage-ring, emittance	1499
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Both unsupervised and supervised machine learning techniques are employed for automatic clustering, modeling and prediction of Advanced Photon Source (APS) storage ring beam lifetime and top-up efficiency archived in operations. The naive Bayes classifier algorithm is developed and combined with k-means clustering to improve accuracy, where the unsupervised clustering of APS beam lifetime and top-up efficiency is consistent with either true label from data archive or Gaussian kernel density estimation. Artificial neural network algorithms have been developed, and employed for training and modelling the arbitrary relations of beam lifetime and top-up efficiency on many observable parameters. The predictions from artificial neural network reasonably agree with the APS operation data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB060
About •	paper received ※ 22 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021
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TUPAB061	Anomaly Detection by Principal Component Analysis and Autoencoder Approach	network, operation, power-supply, storage-ring	1502
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Several different approach are employed to identify the abnormal events in some Advanced Photon Source (APS) operation archived dataset, where dimensionality reduction are performed by either principal component analysis or autoencoder artificial neural network. It is observed that the APS stored beam dump event, which is triggered by magnet power supply fault, may be predicted by analyzing the magnets capacitor temperatures dataset. There is reasonable agreement among two principal component analysis based approaches and the autoencoder artificial neural network approach, on predicting future overall system fault which may result in a stored beam dump in the APS storage ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB061
About •	paper received ※ 22 May 2021 paper accepted ※ 18 June 2021 issue date ※ 19 August 2021
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TUPAB069	The Sabina Terahertz/Infrared Beamline at SPARC-Lab Facility	radiation, electron, experiment, laser	1525
	S. Macis La Sapienza University of Rome, Rome, Italy M. Bellaveglia, M. Cestelli Guidi, E. Chiadroni, F. Dipace, A. Ghigo, L. Giannessi, A. Giribono, L. Sabbatini, C. Vaccarezza INFN/LNF, Frascati, Italy A. Doria, A. Petralia ENEA C.R. Frascati, Frascati (Roma), Italy S. Lupi Sapienza University of Rome, Roma, Italy V. Petrillo INFN-Milano, Milano, Italy
	Funding: SABINA is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program. Following the EU Terahertz (THz) Road Map, high-intensity, ps-long, THz)/Infrared (IR) radiation is going to become a fundamental spectroscopy tool for probing and control low-energy quantum systems ranging from graphene, and Topological Insulators, to novel superconductors* **. In the framework of the SABINA project, a novel THz/IR beamline based on an APPLE-X undulator emission will be developed at the SPARC-Lab facility at LNF-INFN. Light will be propagated from the SPARC-Lab to a new user lab facility nearly 20 m far away. This beamline will cover a broad spectral region from 3 THz to 30 THz, showing ps- pulses and energy of tens of µJ with variable polarization from linear to circular. The corresponding electric fields up to 10 MV/cm, are able to induce non-linear phenomena in many quantum systems. The beamline, open to user experiments, will be equipped with a 5 T magnetic cryostat and will be synchronized with a fs laser for THz/IR pump, VIS/UV probe experiments. [] S.S. Dhillon et al., J. Phys. D: Appl. Phys. 50, 043001 (2017); [] F. Giorgianni et al., Nature Commun. 7, 11421 (2016); [*] P. Di Pietro et al., Phys. Rev. Lett. 124, 226403 (2020);
	Poster TUPAB069 [0.884 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB069
About •	paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 25 August 2021
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TUPAB104	Redesign of the FLASH2 Post-SASE Undulator Beamline	undulator, electron, quadrupole, MMI	1626
	F. Christie, J. Rönsch-Schulenburg, S. Schreiber, M. Vogt, J. Zemella DESY, Hamburg, Germany
	FLASH2 is one of the two SASE (Self-Amplified Spontaneous Emission) undulator beamlines lines comprising variable gap undulators to produce radiation in the XUV and soft X-ray regime at FLASH. Downstream of the SASE undulators the beamline is currently undergoing a major redesign. During shutdowns in summer 2020 and winter 2021 two PolariX TDSs (Polarizable X-band Transverse Deflecting Structure) were installed, as well as additional diagnostics, to monitor the longitudinal phase space density of the electron bunches. Additionally, an afterburner undulator will be integrated in the next shutdown to produce circularly polarized light with wavelengths down to 1.39 nm. In this paper, we will present the modifications that were and will be made to the electron beamline in the course of this redesign.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB104
About •	paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 23 August 2021
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TUPAB114	FEL Performance and Beam Quality Assessment of Undulator Line for the CompactLight Facility.	undulator, FEL, brilliance, electron	1655
	H.M. Castañeda Cortés, D.J. Dunning, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: H2020 CompactLight has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 777431 The H₂020 CompactLight Project aims for the design of innovative, cost-effective, compact FEL facilities to generate higher peak brilliance radiation in the soft and hard X-ray. In this paper we assess via simulation studies the performance of a variably polarising APPLE-X afterburner positioned downstream of a helical Super Conducting Undulator (SCU). We discuss the optimum balance between the active SCU length and the afterburner length, considering the peak brilliance and pulse energy of the output. Our studies are complemented with analysis of the optical beam quality of the afterburner output to determine the design constraints of the photon beamline that delivers the FEL output to the experimental areas. * Mak, A., Salen, P., Goryashko, V., Clarke, J., http://uu.diva-portal.org/smash/record.jsf?pid=diva2\%3A1280300&dswid=3236 ** Lutman, A. et al. Nature Photonics 10, 468
	Poster TUPAB114 [1.210 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB114
About •	paper received ※ 11 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021
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TUPAB141	On the Development of a Low Peak-Power, High Repetition-Rate Laser Plasma Accelerator at IPEN	laser, plasma, electron, experiment	1713
	A. Bonatto Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil E.P. Maldonado ITA, São José dos Campos, Brazil R.P. Nunes UFRGS, Porto Alegre, Brazil R.E. Samad, F.B.D. Tabacow, N.D. Vieira, A.V.F. Zuffi IPEN-CNEN/SP, São Paulo, Brazil
	Funding: FAPESP (Grant #2018/25961), CNPq and CAPES. In this work, the current status on the development of a laser plasma accelerator at the Nuclear and Energy Research Institute (Instituto de Pesquisas Nucleares e Energéticas, IPEN/CNEN), in São Paulo, Brazil, is presented. Short pulses to be produced by an under-development near-TW, kHz laser system will be used to ionize a gas jet, with a density profile designed to optimize the self-injection of plasma electrons. The same laser pulse will also drive a plasma wakefield, which will allow for electron acceleration in the self-modulated regime. The current milestone is to develop the experimental setup, including electron beam and plasma diagnostics, required to produce electron bunches with energies of a few MeV. Once this has been achieved, the next milestone is to produce beams with energies higher than 50 MeV. Besides kickstarting the laser wakefield accelerator (LWFA) technology in Brazil, this project aims to pave the way for conducting research on the production of radioisotopes by photonuclear reactions, triggered by LWFA-accelerated beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB141
About •	paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 10 August 2021
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TUPAB246	Numerical Simulation and Beam-Dynamics Study of a Hollow-Core Woodpile Coupler for Dielectric Laser Accelerators	GUI, laser, acceleration, electron	2022
	G.S. Mauro, D. Mascali, G. Sorbello, G. Torrisi INFN/LNS, Catania, Italy A. Bacci INFN/LASA, Segrate (MI), Italy C. De Angelis, A. Locatelli University of Brescia, Brescia, Italy A.R. Rossi INFN-Milano, Milano, Italy G. Sorbello University of Catania, Catania, Italy
	Hollow core dielectric microstructures powered by lasers represent a new and promising area of accelerator research thanks to the higher damage threshold and accelerating gradients with respect to metals at optical wavelengths. In this paper we present the design of a dielectric Electromagnetic Band Gap (EBG) mode converter for high-power coupling of the accelerating mode in Dielectric Laser Accelerators (DLAs). The design is wavelength-independent, and here we propose an implementation operating at 90.505 GHz (wavelength 3.3 mm) based on a silicon woodpile structure. The coupler is composed by two perpendicularly coupled hollow-core waveguides: a TE-like mode waveguide (excited from RF/laser power) and a TM-like mode accelerating waveguide. The structure has been numerically designed and optimized, presenting Insertion Losses (IL) < 0.3 dB and an efficient mode conversion in the operating bandwidth. The properties and effectiveness of the confined accelerating mode have been optimized in order to derive the needed accelerating gradient. The simulated electric field has been used as input for Astra beam-dynamics simulations in order to compute the beam properties.
	Poster TUPAB246 [2.209 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB246
About •	paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 13 August 2021
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TUPAB287	Application of Artificial Neural Network in the APS Linac Bunch Charge Transmission Efficiency	linac, operation, kicker, controls	2155
	H. Shang, R. Maulik, Y. Sun ANL, Lemont, Illinois, USA T. Xu Northern Illinois University, DeKalb, Illinois, USA
	Funding: * Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. In recent years there has been a rapid growth in machine learning (ML) and artificial intelligence (AI) applications in accelerators. As the scale of complexity and sophistication of modern accelerators grows, the difficulties in modeling the machine increase greatly in order to include all the interacting subsystems and to consider the limitation of various diagnostics to benchmark against measurements. Tools based on ML can help substantially in revealing correlations of machine condition and beam parameters that are not easily discovered using traditional physics model-based simulations, reducing machine tuning up time etc among the many possible applications. While at APS we have many excellent tools for the optimization, diagnostics, and controls of the accelerators, we do not yet have ML-based tools established. It is our desire to test ML in our machine operation, optimization, and controls. In this paper, we introduce the application of neural networks to the APS linac bunch charge transmission efficiency.
	Poster TUPAB287 [0.781 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB287
About •	paper received ※ 12 May 2021 paper accepted ※ 16 June 2021 issue date ※ 29 August 2021
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TUPAB290	Demonstration of Machine Learning Front-End Optimization of the Advanced Photon Source Linac	linac, controls, gun, electron	2163
	A. Hanuka, J.P. Duris SLAC, Menlo Park, California, USA H. Shang, Y. Sun ANL, Lemont, Illinois, USA
	The electron beam for the Advanced Photon Source (APS) at Argonne National Laboratory is generated from a thermionic RF gun and accelerated by an S-band linear accelerator – the APS linac. While the APS linac lattice is set up using a model developed with ELEGANT, the thermionic RF gun front-end beam dynamics have been difficult to model. One of the issues is that beam properties from thermionic guns can vary. As a result, linac front-end beam tuning is required to establish good matching and maximize the charge transported through the linac. A traditional Nelder-Mead simplex optimizer has been used to find the best settings for the sixteen quadrupoles and steering magnets. However, it takes a long time and requires some fair initial conditions. The Gaussian Process (GP) optimizer does not have the initial condition limitation and runs several times faster. In this paper, we report our data collection and analysis for the training of the GP hyperparameters and discuss the application of GP optimizer on the APS linac front-end optimization for maximum bunch charge transportation efficiency through the linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB290
About •	paper received ※ 09 May 2021 paper accepted ※ 28 July 2021 issue date ※ 27 August 2021
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TUPAB316	New Operational Quantities for Radiation Protection by ICRU and ICRP: Impact on Workplaces at Accelerators	radiation, operation, MMI, target	2231
	Th. Otto, M. Widorski CERN, Meyrin, Switzerland
	In radiation protection, Effective Dose E quantifies stochastic radiation detriment. E is defined as a weighted sum of absorbed dose to organs and tissues and cannot be measured directly. ICRU has defined operational quantities to measure effective dose approximately, such as Ambient dose equivalent H(10). At high energies, the estimates provided by H(10) deviate strongly from effective dose. In 2020, ICRU and ICRP have recommended new operational quantities for external radiation with a definition close to the one of effective dose, and published an extensive collection of conversion coefficients from particle fluence to the new quantities (1). Ambient dose H* serves for operational monitoring purposes. The new definition alleviates the observed discrepancies of H(10) with effective dose. In this paper, we present a numerical study of effective dose E, ambient dose equivalent H(10) and ambient dose H* in radiation fields at workplaces at proton- and electron accelerators. These places include locations behind primary shielding, in access mazes and in the vicinity of activated accelerator components. (1) ICRU Report 95, Operational quantities for external radiation
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB316
About •	paper received ※ 11 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021
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TUPAB318	The Beamline Safety Interlock System of Taiwan Photon Source	radiation, vacuum, controls, synchrotron-radiation	2239
	C.F. Chang, C.Y. Chang, C.Y. Liu, H.Y. Yan NSRRC, Hsinchu, Taiwan
	The energy of synchrotron radiation generated by bremsstrahlung radiation and magnet is rather high, which may cause serious radiation damage to human body or even imperil people’s life. The beamline therefore must be equipped with radiation-protection system; in addition, the overheat of optical components exposed to synchrotron radiation will lead to the damage of optical components and devices. In consequence, the beamline should be furnished with the cooling-protection system to cool down optical components and devices. The Beamline Safety Interlock System targets at protecting the personnel and the safety of devices, limiting the radiation dose to a security value for experimental personnel or staffs exposing to radiation on the site as well as preventing beamline components from being exposed to overheat or vacuum damages to improve the effectiveness of beamline.
	Poster TUPAB318 [3.440 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB318
About •	paper received ※ 09 May 2021 paper accepted ※ 10 June 2021 issue date ※ 31 August 2021
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TUPAB340	Design of the Magnetic Shielding for 166 MHz and 500 MHz Superconducting RF Cavities at High Energy Photon Source	cavity, shielding, simulation, superconducting-cavity	2289
	L. Guo, Y. Chen, J. Li, Z.Q. Li, Q. Ma, P. Zhang, X.Y. Zhang, H.J. Zheng IHEP, Beijing, People’s Republic of China
	Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China. Five 166 MHz quarter-wave β=1 superconducting cavities and two 500 MHz single-cell elliptical superconducting cavities have been designed for the storage ring of High Energy Photon Source (HEPS). It is necessary to shield magnetic field for superconducting cavities to reduce the residual surface resistance due to magnetic flux trapping during cavity cool down. The magnetic shielding for both 166 MHz and 500 MHz superconducting cavities have been designed. The residual magnetic field inside the cavities have been calculated by using Opera-3D simulation software. The geographic location of the cavity being installed at the HEPS site and the fringe field of the upstream magnet are considered. These are reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB340
About •	paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 10 August 2021
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TUPAB346	Development of a 500-MHz 150-kW Solid-State Power Amplifier for High Energy Photon Source	GUI, cavity, controls, booster	2312
	Y.L. Luo, T.M. Huang, J. Li, H.Y. Lin, Q. Ma, Q.Y. Wang, P. Zhang, F.C. Zhao IHEP, Beijing, People’s Republic of China
	A 500-MHz 150-kW solid-state power amplifier (SSA) has been developed to test the 500-MHz normal conducting cavities for High Energy Photon Source (HEPS) booster ring. It will also be used to power normal conducting cavities in the initial beam commissioning stage of the HEPS storage ring. A total number of 96 amplifier modules are combined initially by coaxial and later by waveguide combiners to deliver the 150-kW RF power. The final output is of EIA standard WR1800 rectangular waveguide. Each amplifier module consists four transistors equipped with individual circulator and load and outputs 2-kW RF power. Modularity, redundancy and satisfactory RF performance are demonstrated. In the final stage of HEPS project, this 150-kW amplifier will be modified to a 100-kW amplifier to join the other five 100-kW SSAs for normal operation of the booster cavities. The development and test results are presented in this paper.
	Poster TUPAB346 [1.870 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB346
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 15 August 2021
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TUPAB347	Development of a 166-MHz 260-kW Solid-State Power Amplifier for High Energy Photon Source	controls, status, power-supply, cavity	2315
	Y.L. Luo, T.M. Huang, J. Li, H.Y. Lin, Q. Ma, Q.Y. Wang, P. Zhang, F.C. Zhao IHEP, Beijing, People’s Republic of China
	166-MHz 260-kW solid-state power amplifiers have been chosen to drive the 166.6-MHz superconducting cavities for the storage ring of High Energy Photon Source. Highly modular yet compact are desired. A total number of 112 amplifier modules of 3 kW each are combined in a multi-stage power combining topology. The final output is of 9-3/16" 50 Ω coaxial rigid line. Each amplifier module consists of 3 LDMOS transistors with individual circulator and load. Thermal simulations of the amplifier module have been conducted to optimize cooling capabilities for both travelling-wave and full-reflection operation scenarios. High efficiency, sufficient redundancy and excellent RF performances of the 260-kW system are demonstrated. A control system is also integrated and EPICS is used to manage the monitored data. The design and test results of the amplifier system are presented in this paper.
	Poster TUPAB347 [1.972 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB347
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 29 August 2021
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TUPAB373	Design of a Delta-type Superconducting Undulator at the IHEP	undulator, polarization, permanent-magnet, radiation	2391
	J.H. Wei IHEP CSNS, Guangdong Province, People’s Republic of China C.D. Deng DNSC, Dongguan, People’s Republic of China L. Gong, X.Y. Li, X.C. Yang IHEP, Beijing, People’s Republic of China Y. Li DESY, Hamburg, Germany
	Undulators play an important role in the 4th generation radiation light source. In order to satisfy different requirements of the experiments, various undulator structures have been proposed. The Delta-type undulator can provide circular polarized radiation. Conventional undulators are usually made of permanent magnets, but the application of the superconducting technology in the undulator is developing quickly. Compared to the permanent magnet undulators, superconducting undulators can provide higher photon flux with the same magnetic pole gap and period length, especially when the period length is longer than 20 mm. An R&D project is underway to produce a protype of a Delta-type superconducting undulator with 28 mm long period and 12 mm gap at the IHEP. The structure design and the simulation results of the magnetic field are presented in this paper.
	Poster TUPAB373 [1.752 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB373
About •	paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 15 August 2021
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TUPAB375	Commissioning and Operation of Superconducting Multipole Wiggler at Siam Photon Source	MMI, operation, wiggler, electron	2398
	P. Sunwong, S. Boonsuya, S. Chaichuay, T. Chanwattana, Ch. Dhammatong, A. Kwankasem, C.P. Preecha, T. Pulampong, K. Sittisard, V. Sooksrimuang, S. Srichan, P. Sudmuang, N. Suradet, S. Tancharakorn SLRI, Nakhon Ratchasima, Thailand
	A new insertion device, Superconducting Multipole Wiggler (SMPW) with the peak field strength of 3.5 T, was installed in the storage ring of Siam Photon Source as a radiation source for a new hard X-ray beamline. Cool-down process, as well as magnet training, was performed with careful tuning of liquid helium filling procedure for efficient management of liquid helium supply. The filling procedure was also optimized for safe operation of the magnet. The SMPW commission-ing was successfully carried out with electron beam and the effect of SMPW on electron beam dynamics was observed. It can be minimized using quadrupole magnets and horizontal/vertical correctors.
	Poster TUPAB375 [1.160 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB375
About •	paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 31 August 2021
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TUPAB392	Conceptual Design of the Vacuum System for the Future Circular Collider FCC-ee Main Rings	vacuum, collider, quadrupole, scattering	2438
	R. Kersevan, C. Garion CERN, Geneva, Switzerland
	The Future Circular Collider study program comprises several machine concepts for the future of high-energy particle physics. Among them there is a twin-ring e⁻e⁺ collider capable to run at beam energies between 45.6 and 182.5 GeV, i.e. the energies corresponding to the resonances of the Z, W, H bosons and the top quark. The conceptual design of the two 100-km rings has advanced to what is believed to be a working solution, i.e. capability to deal with low-energy (45.6 GeV) high-current (1390 mA) version as well as the high-energy (182.5 GeV) low-current (5.4 mA) one, with intermediate energy and current steps for the other 2 resonances. The limit for all of the versions is given by the 50 MW/beam allotted to the synchrotron radiation (SR) losses. The paper will outline the main beam/machine parameters, the vacuum requirements, and the choices made concerning the vacuum chamber geometry, material, surface treatments, pumping system, and the related pressure profiles. The location of lumped SR photon absorbers for the generic arc cell has been determined. An outline of the studies needed and envisaged for the near future will also be given.
	Poster TUPAB392 [3.036 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB392
About •	paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 25 August 2021
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TUPAB404	Monte Carlo Studies for Shielding Design for High Energy Linac for Medical Isotope Generation	neutron, shielding, radiation, target	2469
	N. Upadhyay, S. Chacko University of Mumbai, Mumbai, India A.P. Deshpande, T.S. Dixit, P.S. Jadhav, R. Krishnan SAMEER, Mumbai, India
	The widely used radioactive tracer Technetium-99m (99mTc) is traditionally produced from Uranium via 235U (n, f) 99Mo reactions which depends heavily on nuclear reactors. Design studies for an alternative, cleaner approach for radioisotope generation using a high energy electron linac were initiated at SAMEER to generate 99Mo. The electron beam from a 30 MeV linac with an average current of 350 µA will be bombarded on a convertor target to produce X-rays which will be bombarded on enriched 100Mo target to produce 99Mo via (g, n) reaction. 99mTc will be eluted from 99Mo. The photons and neutrons produced in the process should be shielded appropriately to ensure radiation safety. This paper brings out the use of Monte Carlo techniques for photon and neutron shielding for our application. We used FLUKA to calculate the fluence, angular distribution and dose for photons and neutrons. Then, we introduced various layers of lead followed by HDPE, 5% borated HDPE and 40% boron rubber to ensure that the proposed shielding is sufficient to completely shield the photon as well as neutron radiation and hence is safe for operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB404
About •	paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 25 August 2021
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TUPAB409	FLUKA and Geant4 Monte Carlo Simulations of a Desktop, Flat Panel Source Array for 3D Medical Imaging	simulation, electron, experiment, detector	2483
	T. Primidis, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom T. Primidis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom V. Soloviev Adaptix Imaging, Didcot, United Kingdom
	Funding: Funded by the Accelerators for Security, Healthcare and Environment CDT from the United Kingdom Research and Innovation Science and Technology Facilities Council, reference ID ST/R002142/1 Digital tomosynthesis (DT) is a 3D imaging modality with a lower cost and lower dose than computed tomography. A DT system made of a flat panel array with 45 X-ray sources, but compact enough to fit on the desktop is near market realisation by the company Adaptix Ltd. This work presents a framework of FLUKA and Geant4 Monte Carlo (MC) simulations of the Adaptix system including the X-ray beam generation and the final image quality. The results show that MC methods offer an insight into the performance details of such an innovative device at different levels between the X-ray emitter array and the detector. As such, a large portion of the design and optimisation of such novel X-ray imaging systems can be done with a single toolkit. Finally, the modularity of the approach allows other tools to be imported at various steps within the framework and thus provide answers to questions that cannot be addressed by general-purpose MC codes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB409
About •	paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 24 August 2021
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TUPAB410	Finite Element Analysis and Experimental Validation of Low-Pressure Beam Windows for XCET Detectors at CERN	experiment, Windows, detector, background	2487
	J. Buesa Orgaz, M. Brugger, G. Romagnoli, O. Sacristan De Frutos, F. Sanchez Galan CERN, Meyrin, Switzerland
	In the framework of the renovation and consolidation of experimental areas at CERN, a low-pressure design beam superimposed windows (250 µm Mylar and 150 µm polyethylene) for the Threshold Cherenkov counters (XCET) has been modelled and verified for its implementation. The XCET is a detector used to count the number of selected charged particles in the beam by adjusting the pressure that leads to the emission of Cherenkov photons only above certain pressure threshold. Simultaneously, the charged particles pass from a vacuum environment to the pressurized refractive gas vessel through a solid interface. Minimal material in this solid interface is therefore crucial to avoid interactions of the low-energy particles which may lead to beam intensity loss or background production. Hence, thin and low-density materials are required to mitigate multiple scattering and energy loss of the incoming particles while still allowing the needed pressures inside the counter vessel. A XCET validation methodology was conducted using Finite Element Analysis (FEA), followed by experimental validations performing burst pressure tests and using Digital Image Correlation (DIC).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB410
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 24 August 2021
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WEXC04	Simulations of Beam Strikes on Advanced Photon Source Upgrade Collimators using FLASH, MARS, and elegant	simulation, electron, storage-ring, radiation	2562
	J.C. Dooling, M. Borland, A.M. Grannan, C.J. Graziani, R.R. Lindberg, G. Navrotski ANL, Lemont, Illinois, USA N.M. Cook RadiaSoft LLC, Boulder, Colorado, USA D.W. Lee, Y. Lee UCSC, Santa Cruz, California, USA
	Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357. Modeling of high-energy-density electron beams on collimators proposed for the Advanced Photon Source Upgrade (APS-U) storage ring (SR) is carried out with codes FLASH, MARS, and elegant. Code results are compared with experimental data from two separate beam dump studies conducted in the present APS SR. Whole beam dumps of the 6-GeV, 200 mA, ultra-low emittance beam will deposit acute doses of 30 MGy within 10 to 20 microseconds, leading to hydrodynamic behavior in the collimator material. Goals for coupling the codes include accurate modeling of the hydrodynamic behavior, methods to mitigate damage, and understanding the effects of the resulting shower downstream of the collimator. Relevant experiments, though valuable, are difficult and expensive to conduct. The coupled codes will provide a method to model differing geometries, materials, and loss scenarios. Efforts thus far have been directed toward using FLASH to reproduce observed damage seen in aluminum test pieces subjected to varying beam strike currents. Stabilizing the Eulerian mesh against large energy density gradients as well as establishing release criteria from solid to fluid forms are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXC04
About •	paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 30 August 2021
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WEXC05	First Results Operating a Long-Period EPU in Universal Mode at the Canadian Light Source	polarization, focusing, undulator, injection	2566
	W.A. Wurtz, C.K. Baribeau, D. Bertwistle, M.J. Sigrist CLS, Saskatoon, Saskatchewan, Canada
	The Quantum Materials Spectroscopy Centre beamline at the Canadian Light Source (CLS) requires photons with energies as low as 15 eV with circular polarization at the end station. This energy range is accomplished on the 2.9 GeV CLS storage ring using an elliptically polarizing undulator (EPU) with a 180 mm period, which we call EPU180. In order to realize circular polarized photons at the end station with this low energy, we must overcome two technical issues. First, the beamline optics distort the polarization of the light, so we compensate by providing light with a flattened, tilted polarization ellipse at the source point - a mode of operation known as universal mode. Second, the device has a strong effect on the electron beam due to dynamic focusing and is capable of reducing the injection efficiency to zero. We overcome this non-linear dynamic focusing using current strips adhered to the vacuum chamber. In this report, we present the first results with operating EPU180 in universal mode and we recover the dynamic aperture using the current strips.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXC05
About •	paper received ※ 13 May 2021 paper accepted ※ 05 July 2021 issue date ※ 11 August 2021
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WEPAB021	Development and Testing of a Cherenkov Beam Loss Monitor in CLEAR Facility	experiment, detector, electron, beam-losses	2640
	S. Benitez Berrocal, E. Effinger, W. Farabolini, A. Gilardi, P. Korysko, E. Lima, B. Salvachua, W. Viganò CERN, Geneva 23, Switzerland P. Lane University of Huddersfield, Huddersfield, United Kingdom
	Beam Loss Monitors are fundamental diagnostic systems in particle accelerators. Beam losses are measured by a wide range of detectors with excellent results; most of these devices are used to measure local beam losses. However, in some accelerators there is the need to measure beam losses continuously localized over longer distances i.e., several tens of meters. For this reason, a beam loss detector based on long optical fibres is now under study. As part of the design, several simulations, comparing different possible detection scenarios, have been performed in FLUKA and bench-marked with experimental data. An experimental campaign was performed with an electron beam in the CERN Linear Electron Accelerator for Research (CLEAR) in November 2020. The light emitted from the optical fibre was captured using Silicon Photo-Multipliers (SiPM) coupled at each fibre’s end. In this poster, the first results of a beam loss detector based on the capture of Cherenkov photons generated by charged particles inside multimode silica fibres are presented.
	Poster WEPAB021 [0.724 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB021
About •	paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 31 August 2021
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WEPAB029	Challenges for the Interaction Region Design of the Future Circular Collider FCC-ee	detector, simulation, background, collider	2668
	M. Boscolo, A. Ciarma, F. Fransesini, L. Pellegrino INFN/LNF, Frascati, Italy N. Bacchetta INFN- Sez. di Padova, Padova, Italy M. Benedikt, H. Burkhardt, M.A. Jones, R. Kersevan, M. Lueckhof, E. Montbarbon, K. Oide, L. Watrelot, F. Zimmermann CERN, Meyrin, Switzerland L. Brunetti, M. Serluca IN2P3-LAPP, Annecy-le-Vieux, France M. Dam NBI, København, Denmark M. Koratzinos MIT, Cambridge, Massachusetts, USA M. Migliorati INFN-Roma1, Rome, Italy A. Novokhatski, M.K. Sullivan SLAC, Menlo Park, California, USA F. Poirier CNRS - DR17, RENNES, France
	Funding: This work was partially supported by the EC HORIZON 2020 project FCC-IS, grant agreement n.951754, and by the U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-76SF-00515. The FCC-ee is a proposed future high-energy, high-intensity and high precision lepton collider. Here, we present the latest developments for the FCC-ee interaction regions, which shall ensure optimum conditions for the particle physics experiments. We discuss measures of background reduction and a revised interaction region layout including a low impedance compact beam chamber design. We also discuss the possible impact of the radiation generated in the interaction region including beamstrahlung.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB029
About •	paper received ※ 11 May 2021 paper accepted ※ 23 June 2021 issue date ※ 30 August 2021
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WEPAB062	Investigation of the Thomson Scattering Influence on Electron Beam Parameters in an Energy-Recovering Linear Accelerator on the Example of MESA	electron, scattering, HOM, laser	2732
	C.L. Lorey, K. Aulenbacher, A. Meseck KPH, Mainz, Germany
	Funding: funded by DFG through GRK2128 ACCELENCE At the Johannes Gutenberg University (JGU) in Mainz, the Mainz Energy-recovering Superconducting Accelerator (MESA) is currently under construction. It is designed to deliver electron beams of up to 155 MeV. As it can be operated in an energy-recovery (ER) mode thus allowing for high repetition rate, it is a promising candidate for a high flux Thomson scattering based gamma source. This paper will provide a status update on the study of the impact of Thomson scattering on electron beam parameters and the underlying mechanics. Further, the implementation into a simulation code will be discussed.
	Poster WEPAB062 [1.307 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB062
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 02 September 2021
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WEPAB067	High Duty Cycle EUV Radiation Source Based on Inverse Compton Scattering	laser, electron, gun, emittance	2748
	R. Huang, Q.K. Jia, C. Li USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: Work supported by the National Natural Science Foundation of China Grant Number 11805200, and National Key Research and Development Program of China No. 2016YFA0401901. ICS can obtain quasi-monochromatic and directional EUV radiation via a MeV-scale energy electron beam and a micron-scale wavelength laser beam, which enables a dramatic reduction in dimension and expense of the system, and makes it an attractive technology in research, industry, medicine and homeland security. Here we describe an EUV source based on high repetition ICS system. The scheme exploits the output from the laser-electron interaction between a MW-ps laser at MHz repetition-rate and a high quality electron beam with an energy of a few MeV at MHz repetition-rate.
	Poster WEPAB067 [1.551 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB067
About •	paper received ※ 23 May 2021 paper accepted ※ 24 June 2021 issue date ※ 02 September 2021
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WEPAB075	Xenos: X-Ray Monte Carlo Code Suite	electron, simulation, positron, operation	2766
	S. Humphries Field Precision, Albuquerque, New Mexico, USA
	Xenos is an integrated 3D code suite for the design of X-ray sources and electron beam devices. The component programs run under all versions of Windows. This paper describes unique features of Xenos compared to other Monte Carlo packages: 1) representation of geometry and deposited dose on a finite-element mesh supported by an interactive mesh generator, 2) inclusion of full 3D electric and magnetic fields in Monte Carlo simulations, 3) an integrated user environment for input and output calculations (e.g., electron gun design, target heating, …) and 4) extended parallel-computing support for high-accuracy solutions. Xenos employs the full capabilities of multi-core computers and allows parallel computations on an unlimited number of independent computers. * Sempau J., et.al. (2003), "Experimental benchmarks of the Monte Carlo code PENELOPE", Nucl. Instrum. Meth. B 207, 107-123.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB075
About •	paper received ※ 10 May 2021 paper accepted ※ 23 June 2021 issue date ※ 25 August 2021
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WEPAB080	Near Threshold Pion Photoproduction on Deuterons	experiment, multipole, polarization, scattering	2775
	V. Shastri, V. Aswathi, S.P. Shilpashree Christ University, School of Engineering and Technology, Bangalore, India
	The study of photoproduction of mesons is a prime tool in understanding the properties of strong interactions. The only photoproduction reaction on deuteron with two-body final state is coherent pion photoproduction reaction. Several theoretical studies are being carried out on the pion photoproduction on deuterons since several decades. On the experimental side, the accelerator and detector technology has improved the developments. In the recent years, measurements of tensor analyzing powers associated with coherent and incoherent pion photoproduction are also being carried out at the VEPP-3 electron storage ring. In one of the recent measurements, Rachek et al"" have observed discrepancy between theory and experiment at higher photon energies and have suggested for improvement of the theoretical models. In a more recent analysis,"" the role of D-wave component on spin asymmetries have been identified. In view of these developments, the purpose of the present contribution is to study coherent pion photoproduction on deuterons using model independent irreducible tensor formalism developed earlier to study the photodisintegration of deuterons."*" I A Rachek et al., Few-Body Syst., 58, 29 (2017) H M Al Ghamdi et al, Brazillian Journal of Physics, 50, 615 (2020) * G Ramachandran, S P Shilpashree Phys. Rev. C 74, 052801(R) (2006)
	Poster WEPAB080 [0.203 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB080
About •	paper received ※ 29 May 2021 paper accepted ※ 01 July 2021 issue date ※ 16 August 2021
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WEPAB087	Observation of Undulator Radiation Generated by a Single Electron Circulating in a Storage Ring and Possible Applications	synchrotron, electron, radiation, undulator	2790
	I. Lobach University of Chicago, Chicago, Illinois, USA A. Halavanau, Z. Huang SLAC, Menlo Park, California, USA K. Kim ANL, Lemont, Illinois, USA S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev Fermilab, Batavia, Illinois, USA
	An experimental study into the undulator radiation, generated by a single electron was carried out at the Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab. The individual photons were detected by a Single Photon Avalanche Diode (SPAD) at an average rate of 1 detection per 300 revolutions in the ring. The detection events were continuously recorded by a picosecond event timer for as long as 1 minute at a time. The collected data were used to test if there is any deviation from the classically predicted Poissonian photostatistics. It was motivated by the observation * of sub-Poissonian statistics in a similar experiment. The observation * could be an instrumentation effect related to low detection efficiency and long detector dead time. In our experiment, the detector (SPAD) has a much higher efficiency (65%) and a much lower dead time. In addition, we show that the collected data (recorded detection times) can be used to study the synchrotron motion of a single electron and infer some parameters of the ring. For example, by comparing the results of simulation and measurement for the synchrotron motion we were able to estimate the magnitude of the RF phase jitter. * Teng Chen and John M. J. Madey, Phys. Rev. Lett. 86, 5906, June 2001
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB087
About •	paper received ※ 17 May 2021 paper accepted ※ 24 June 2021 issue date ※ 16 August 2021
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WEPAB099	Near-Threshold Nonlinear Photoemission From Cu(100)	electron, laser, cathode, experiment	2822
	C.J. Knill, S.S. Karkare Arizona State University, Tempe, USA H.A. Padmore LBNL, Berkeley, California, USA
	Funding: National Science Foundation Grant No. PHY-1549132 Photocathodes that have a low mean transverse energy (MTE) are crucial to the development of compact X-ray Free Electron Lasers (XFEL) and ultrafast electron diffraction (UED) experiments. For FELs, low MTE cathodes result in a lower requirement for electron energy when lasing at a defined energy, and for a defined electron energy result in lasing at higher energy. For UED experiments, low MTE cathodes give a longer coherence length, allowing measurements on larger unit cell materials. A record low MTE of 5 meV has been recently demonstrated from a Cu (100) surface when measured near the photoemission threshold and cooled down to 30 K with liquid Helium []. For UED and XFEL applications that require a high charge density, the low quantum efficiency of Cu (100) near threshold necessitates the use of a high laser fluence to achieve the desired charge density []. At high laser fluences the MTE is limited by nonlinear effects, and therefore it is necessary to investigate near photoemission threshold at these high laser fluences. In this paper we report on nonlinear, near-threshold photoemission from a Cu (100) cathode, and its effect on the MTE. S. Karkare et al, Phys. Rev. Lett. 125, 054801 (2020) ** J. Bae et al, J. Appl. Phys., 124, 244903 (2018)
	Poster WEPAB099 [0.829 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB099
About •	paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 29 August 2021
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WEPAB112	Performance Characterisation of a Cu (100) Single-Crystal Photocathode	cathode, electron, emittance, experiment	2860
	L.A.J. Soomary, D.P. Juarez-Lopez, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom L.B. Jones, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The search for high performance photocathode electron sources is a priority in the accelerator science community. The surface characteristics of a photocathode define important factors of the photoemission including the intrinsic emittance, the quantum efficiency and the work function of the photocathode. These factors in turn define the electron beam performance which are measurable as emittance, brightness and energy spread. We have used ASTeC’s Multiprobe (SAPI)* to characterise and analyse photocathode performance using multiple techniques including XPS, STM, and LEED imaging, and their Transverse Energy Spread Spectrometer (TESS)** to measure mean transverse energy (MTE). We present characterisation measurements for a Cu (100) single-crystal photocathode sample with data from SAPI confirming the crystallographic face and showing surface composition and roughness, supported by data from TESS showing the photocathode electron beam energy spread. * B.L. Militsyn, 4-th EuCARD2 WP12.5 meeting, Warsaw, 14-15 March 2017 **Proc. FEL’13, TUPPS033, 290-293
	Poster WEPAB112 [0.814 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB112
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 22 August 2021
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WEPAB127	Accurate Measurements of Undulator Particle Beam Entrance/Exit Angles Using Improved Hall Probes and Calibration Process	undulator, insertion, insertion-device, closed-orbit	2907
	I. Vasserman, R.J. Dejus, Y. Piao, M.F. Qian, J.Z. Xu ANL, Lemont, Illinois, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357. The Advanced Photon Source Upgrade (APS-U) undulator requirements were changed from the first and second field integrals to the entrance and exit angles of the particle beam. This provides the user with the best radiation view angle by the storage ring closed orbit correction system. To satisfy such requirements we use improved Senis Hall probes and calibration process. In addition to the normal NMR calibration of the sensors, the calibration was further refined using stretch-coil integrals to make accurate measurements.
	Poster WEPAB127 [0.620 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB127
About •	paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 19 August 2021
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WEPAB128	Recent Experience with Magnet Sorting for APS-U Hybrid Undulators	undulator, quadrupole, permanent-magnet, synchrotron	2910
	I. Vasserman, R.J. Dejus, Y. Piao, M.F. Qian, J.Z. Xu ANL, Lemont, Illinois, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357. The quality of permanent magnets plays a particularly important role in undulator performance. Many different types of magnet sorting to enhance undulator performance have been carried out at different facilities. Meanwhile, progress in improving magnet quality has been made by different vendors. At the Advanced Photon Source (APS) we have assembled, measured, and analyzed over 14 new undulators of the same mechanical design, some of them with sorted magnets and some unsorted. The performance differences appear to be insignificant in meeting the tight APS Upgrade (APS-U) undulator requirements.
	Poster WEPAB128 [0.395 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB128
About •	paper received ※ 16 May 2021 paper accepted ※ 09 June 2021 issue date ※ 10 August 2021
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WEPAB132	Towards a Superconducting Undulator Afterburner for the European XFEL	FEL, undulator, electron, vacuum	2921
	S. Casalbuoni, J.E. Baader, G. Geloni, V. Grattoni, D. La Civita, C. Lechner, B. Marchetti, S. Serkez, H. Sinn EuXFEL, Schenefeld, Germany W. Decking, L. Lilje, S. Liu, T. Wohlenberg, I. Zagorodnov DESY, Hamburg, Germany
	We propose to develop, characterize and operate a superconducting undulator (SCU) afterburner consisting of 5 undulator modules (1 module = 2 times SCU coil of 2 m length and 1 phase shifter) at the SASE2 hard X-ray beamline of European XFEL. This afterburner has the potential to produce an output of more than 10¹⁰ ph/pulse at photon energies above 30 keV. The project is divided into the production of a pre-series prototype module and a small-series production of 5 modules. Central goals of this R&D activity are: the demonstration of the functionality of SCUs at an X-ray FEL, the set up of the needed infrastructure to characterize and operate SCUs, the industrialization of such undulators, and the reduction of the price per module. In this contribution, the main parameters and specifications of the pre-series prototype module (S-PRESSO) are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB132
About •	paper received ※ 15 May 2021 paper accepted ※ 05 July 2021 issue date ※ 14 August 2021
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WEPAB209	Review of Medical Accelerator Development at Sameer, India	linac, electron, cavity, acceleration	3113
	T.S. Dixit, N. Bansode, A.P. Bhagwat, S.T. Chavan, A.P. Deshpande, G. Gaikwad, S. Ghosh, R. Krishnan, C.S. Nainwad, G.D. Panchal, S.N. Pethe, K.A. Thakur, V.B. Ukey, M.M. Vidwans SAMEER, Mumbai, India
	Funding: Ministry of Electronics and Information Technology (MeitY), Government of India At the Medical Electronics Division of SAMEER, R&D for the development of a 4 MeV energy electron linac for Cancer therapy was taken up in the late ’80s. An S-band standing wave side coupled structure operating at pi/2 mode was developed for electron acceleration. The linac was integrated with other subsystems in collaboration with CSIO and PGIMER and the first machine was commissioned at PGI, Chandigarh in 1990. Thereafter, a lot of modifications like energy, dose rate, iso-center height etc. were made in the system, and later 4 more machines were commissioned in hospitals for treatment. More than 1,50,000 patients have been treated using SAMEER’s 6 MeV oncology system. Subsequently, development of dual-mode and variable energy electron and photon output machines was undertaken. Two-photon energies of 6 and 15 MV and multiple electron energies starting from 6 to 18 MeV for treatment was offered from the linac. The electron energy variation was done using plunger mechanism in the side coupling cavity. This linac was successfully baked and RF tested for various parameters. This paper describes the experimental parameters achieved for both low and high energy dual-mode linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB209
About •	paper received ※ 14 May 2021 paper accepted ※ 07 July 2021 issue date ※ 13 August 2021
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WEPAB255	Simulation Studies on the Interactions of Electron Beam with Wastewater	electron, radiation, simulation, target	3236
	X. Li, H. Baumgart, G. Ciovati ODU, Norfolk, Virginia, USA G. Ciovati, F.E. Hannon, S. Wang JLab, Newport News, Virginia, USA
	Funding: Jefferson Lab LDRD The manufactured chemical pollutants, like 1,4 dioxane and PFAS (per- and polyfluroralkyl substances), found in the underground water and/or drinking water are challenging to be removed or biodegraded. Energetic electrons are capable of mediating and removing them. This paper utilizes FLUKA code to evaluate the beam-wastewater interaction effects with different energy, space and divergence distributions of the electron beam. With 8 MeV average energy, the electron beam exits from a 0.0127 cm thick titanium window, travels through a 4.3 cm distance air and a second 0.0127 cm thick stainless water container window with 2.43 cm radius, and finally is injected into the water area, where the volume of water is around 75 cubic cm. The distribution parameters of the electron beam are from the GPT (General Particle Tracer) simulations for UITF (Upgraded Injector Test Facility) in Jefferson lab. By varying the distributions, several measurements including the dose (or energy deposition) distribution, electron fluence, photon fluence are scored and compared. Taking the comparisons into consideration, this paper is aiming to find better electron beams for the wastewater irradiation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB255
About •	paper received ※ 20 May 2021 paper accepted ※ 25 June 2021 issue date ※ 14 August 2021
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WEPAB340	Pressure Simulations for the EIC Interaction Region	vacuum, electron, detector, simulation	3483
	M.L. Stutzman JLab, Newport News, Virginia, USA
	Background detector rates in the Electron Ion Collider depend in part on the pressure in the interaction region. Materials choice, synchrotron radiation induced desorption, conditioning time and pumping configuration all affect the pressure in the system. Simulations of the region using Synrad and Molflow+ coupled simulation codes will be presented for various configruations and conditioning times.

Paper

Title

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MOXA02

Status of the APS-U Project

emittance, lattice, injection, storage-ring

7

R.O. Hettel
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Sci- ence, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357.
The Advanced Photon Source Upgrade (APS-U) project at the Argonne National Laboratory will re-place the existing 7-GeV, 1.1-km circumference dou-ble bend storage ring lattice with a new 6-GeV hybrid 7BA lattice that will reduce horizontal electron emit-tance from 3 nm-rad to 42 pm-rad, including IBS ef-fects for 200-mA operation. With new optimized per-manent magnet and superconducting undulators, an increase in spectral brightness of two to three orders of magnitude in the 10-100 keV X-ray energy range will be realized. The project includes nine new high performance beamlines and fifteen enhanced beam-lines that will exploit the high brightness and coher-ence of the new facility. The project is in full swing, more than 50% complete by cost, and is on schedule for first beam sometime in mid-2024, a slip of 10 months from the original schedule due to the impact of COVID-19. Project status, challenges and outstanding issues will be discussed in this article.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXA02

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paper received ※ 21 May 2021 paper accepted ※ 09 June 2021 issue date ※ 11 August 2021

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MOPAB018

SASE Gain-Curve Measurements with MCP-Based Detectors at the European XFEL

FEL, detector, undulator, radiation

96

E. Syresin, O.I. Brovko, A.Yu. Grebentsov
JINR, Dubna, Moscow Region, Russia
W. Freund, J. Grünert, J. Liu, Th. Maltezopoulos, D. Mamchyk
EuXFEL, Schenefeld, Germany
M.V. Yurkov
DESY, Hamburg, Germany

Radiation detectors based on microchannel plates (MCP) are used for characterization of the Free-Electron Laser (FEL) radiation and measurements of the Self-amplified spontaneous emission (SASE) gain curve at the European XFEL. Photon pulse energies are measured by the MCPs with an anode and by a photodiode. There is one MCP-based detector unit installed in each of the three photon beamlines downstream of the SASE1, SASE2, and SASE3 undulators. MCP detectors operate in a wide dynamic range of pulse energies, from the level of spontaneous emission up to FEL saturation. Their wavelength operation range overlaps with the whole range of radiation wavelengths of SASE1 and SASE2 (from 0.05 nm to 0.4 nm), and SASE3 (from 0.4 nm to 5 nm). In this paper we present results of SASE gain-curve measurements by the MCP-based detectors.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB018

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paper received ※ 18 May 2021 paper accepted ※ 17 August 2021 issue date ※ 23 August 2021

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MOPAB042

Beam Dynamics Investigation for a New Project of Compton Back Scattering Photon Source at NRNU MEPhI

linac, electron, scattering, laser

186

V.S. Dyubkov, I.A. Ashanin, M. Gusarova, Yu.D. Kliuchevskaia, M.V. Lalayan, S.M. Polozov, A.I. Pronikov, V.I. Rashchikov
MEPhI, Moscow, Russia

Funding: This project is supported by Russian Foundation for Basic Research, Grant no. 19-29-12036.
The activities on physical models design of a compact monochromatic radiation source in the x-ray range based on inverse Compton scattering are started at NRNU MEPhI. There are comparison of two schemes of the photon source here: one of them is considered to be based on linac with variable energy of 20-60 MeV only and the other one is considered as accelerator complex where linac is supposed to be used as injector to medium size storage ring (energy up to 60 MeV). Preliminary results of linac structures and storage ring design as well as electron dynamics simulation are discussed

Poster MOPAB042 [0.962 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB042

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paper received ※ 13 May 2021 paper accepted ※ 20 May 2021 issue date ※ 10 August 2021

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MOPAB044

Gas Bremsstrahlung Measurements in the Advanced Photon Source Storage Ring

radiation, operation, detector, injection

193

J.C. Dooling, A.R. Brill, J.R. Calvey
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357.
In the Advanced Photon Source Upgrade storage ring (SR), small-aperture vacuum chambers provide limited conductance for pumping. Non-evaporable getter (NEG) coatings will be used in the SR to support the vacuum. Ion pumps and cold-cathode gauges are typically located away from the vacuum chamber transporting the beam. Measuring gas bremsstrahlung (GB) photons in low-conductance chambers provides a method to determine the pressure at the beam location. We report on GB measurements made in the ID-25 beamline. A Pb:Glass calorimeter radiator generates Cherenkov radiation when high-energy photons cause pair-production within the glass. A photomultiplier tube converts the light pulses to electrical signals. Data was obtained during normal machine operations starting in January 2020. Data collection was facilitated using a 4-channel ITech Beam Loss Monitor FPGA that allows for control of thresholds and attenuation settings in both counting and pulse-height acquisition modes. Count rates and spectra were recorded for the three primary fill patterns typically used during SR operations as well as during gas injection experiments; results of these measurements will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB044

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paper received ※ 22 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021

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MOPAB055

Generation of Coherent Attosecond X-ray Pulses in the Southern Advanced Photon Source

laser, electron, storage-ring, emittance

237

W. Liu, Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Jiao, S. Wang
IHEP, Beijing, People’s Republic of China

Southern Advanced Photon Source (SAPS) is a fourth-generation storage ring light source that has been considered for construction in Guangdong province of China, adjacent to the China Spallation Neutron Source. As a low-emittance storage ring, the natural emittance of SAPS is below 100 pm. One of the benefits is that the brightness is about 2 orders high than 3rd generation light sources. However, like many other storage ring-based light sources, the time resolution is limited by the electron bunch length in the range of picoseconds. In this work, we propose a new scheme for the generation of coherent attoseconds X-ray pulses with a high repetition rate in SAPS. A numerical demonstration of the scheme is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB055

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paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 26 August 2021

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MOPAB058

Swap-Out Safety Tracking for the Advanced Photon Source Upgrade

dipole, simulation, electron, power-supply

249

M. Borland, J.S. Downey, M.S. Jaski
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source upgrade will operate in swap-out mode, which is similar to top-up but involves complete replacement of individual depleted bunches in a single shot. As with top-up, safety is a concern given that this process will take place with beamline shutters open. We describe the methods used to model swap-out safety, including creation and validation of a full ring lattice based on 3D field maps. We also describe a new method of implementing complex, intersecting channels for electron beams and photon beams, as well as a method of easily identifying potentially dangerous stray particles. Numerous potential errors (e.g., magnet shorts) were modeled, giving a reliable indication of performance of proposed stored beam and magnet interlocks.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB058

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paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 29 August 2021

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MOPAB073

Beam Loss Simulations During Beam Dumping in Heps

kicker, lattice, simulation, dumping

294

X. Cui, Y. Jiao, Y.L. Zhao
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is a 6 GeV storage ring light source under construction in China. Several collimators installed in the vacuum chamber will be used as beam dump in the storage ring operation. Preliminary simulations showed that the temperature rise caused by the beam power deposited on the collimators will far exceed the melting point of the collimator material. In order to cure this problem, special kickers are proposed to be installed in the ring to modulate the beam during beam dumping, thereby increasing the size of the beam hit on the collimators. In this article, some simulation results of the density of particles on the collimators during beam dumping for different HEPS lattice and different kicker parameters are shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB073

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paper received ※ 17 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021

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MOPAB075

Proposal of the Southern Advanced Photon Source and Current Physics Design Study

linac, storage-ring, lattice, emittance

300

S. Wang, J. Chen, L. Huang, Y. Jiao, B. Li, Z.P. Li, W. Liu, S.Y. Xu
IHEP, Beijing, People’s Republic of China
Y. Han, X.H. Lu, Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China
X. Liu
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan

It has been considered to build a mid-energy fourth-generation storage ring light source neighbouring the China Spallation Neutron Source, in Guangdong Province, the south of China. The light source is named the Southern Advanced Photon Source (SAPS). Preliminary physics design studies on the SAPS have been implemented for a few years. In this paper, we will describe considerations of technical roadmap and key parameter choice for this light source, and introduce the up-to-date lattice designs and related physics studies on the SAPS.

Poster MOPAB075 [1.689 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB075

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paper received ※ 12 May 2021 paper accepted ※ 20 May 2021 issue date ※ 21 August 2021

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MOPAB084

Acceptance Tests and Installation of the IVU and Front End for the XAIRA Beamline of ALBA

undulator, vacuum, experiment, insertion

318

J. Campmany, J. Marcos, V. Massana
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

XAIRA is a new beamline being built at ALBA synchrotron for macromolecular crystallography (MX) devoted to the study of small bio crystals. It aims at providing a full beam with a size of 3x1 µm² FWHM (hxv) and flux of >3·10¹² ph/s (250 mA in Storage Ring) at 1 Å wavelength (12.4 keV) to tackle MX projects for which only tiny (<10 μm) or imperfect crystals are obtained. Besides, XAIRA aims at providing photons at low energies, down to 4 keV, to support MX experiments exploiting the anomalous signal of the metals naturally occurring in proteins (native phasing), which is enhanced in the case of small crystals and long wavelengths. To this end, an in-vacuum undulator has been built by a consortium between Kyma and Research Instruments companies. In this paper, we present the results of the Site Acceptance Tests made at ALBA using a new bench developed to measure closed structures, and also the steps done for its installation in the ALBA tunnel.

Poster MOPAB084 [1.715 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB084

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paper received ※ 11 May 2021 paper accepted ※ 20 May 2021 issue date ※ 25 August 2021

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MOPAB085

Design and Fabrication of a Short Multipole Wiggler and the Front End for the New ALBA Beamline FAXTOR

wiggler, vacuum, insertion, insertion-device

321

J. Campmany, J. Marcos, V. Massana
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

FAXTOR is a new hard XR tomography beam line that is being built at ALBA in order to fulfil the needs that cannot be currently covered by the MISTRAL VUV and soft XR beamline. This beam line needs a small source size as well higher than 10¹² Photons per second through an aperture of 4x1 mm2 in the whole range 5 to 60 keV, for a current of 250 mA in Storage Ring with source size maintained below 310 µm horizontal and 25 µm vertical. The contract was awarded to AVS-US Company. In this paper we present the design finally selected as well as the preliminary design carried out by manufacturer to implement the conceptual model designed by ALBA.

Poster MOPAB085 [1.879 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB085

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paper received ※ 11 May 2021 paper accepted ※ 20 May 2021 issue date ※ 31 August 2021

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MOPAB086

Design of Front End and a 3-Pole-Wiggler as a Photon Source for BEATS Beamline at SESAME

wiggler, vacuum, synchrotron, insertion

324

J. Campmany, J. Marcos
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
M. Al Nadjawi, M. Attal, G. Lori
SESAME, Allan, Jordan
I. Cudin
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
S. Guiducci
INFN/LNF, Frascati, Italy
P. Van Vaerenbergh
ESRF, Grenoble, France

BEATS is an international collaboration funded by EU in order to design and implement an XR tomography beam line in SESAME Jordanian synchrotron. ALBA contribution consists in the design of the photon source and the Front End elements. In this paper we present the conceptual designs of both the 3-pole wiggler uses as photon source as well as the Front End elements designed for the beamline.

Poster MOPAB086 [2.306 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB086

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paper received ※ 11 May 2021 paper accepted ※ 21 May 2021 issue date ※ 17 August 2021

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MOPAB090

Status of HEPS Insertion Devices Design

undulator, radiation, wiggler, insertion

339

X.Y. Li, Y. Jiao, H.H. Lu, S.K. Tian
IHEP, Beijing, People’s Republic of China

HEPS is a 4th generation light source with the energy of 6 GeV and ultralow emittance of 34 pm.rad. A total of 14 beamlines with 19 insertion devices has been planned in the first phase, including 6 cryogenic undulators, 5 in-vacuum undulators, and two special non-planar IDs. The schemes and parameters of all the IDs are planned to be determined in this year. We report on the status of the design of these IDs and their effects on beam dynamics.

Poster MOPAB090 [0.633 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB090

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paper received ※ 13 May 2021 paper accepted ※ 01 July 2021 issue date ※ 10 August 2021

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MOPAB096

Rocking Curve Imaging Experiment at SSRL 10-2 Beamline

wiggler, experiment, radiation, lattice

357

A. Halavanau, R. Arthur, B. Johnson, J.P. MacArthur, G. Marcus, R.A. Margraf, Z. Qu, T. Rabedeau, T. Sato, C.J. Takacs, D. Zhu
SLAC, Menlo Park, California, USA

Stanford Synchrotron Radiation Lightsource (SSRL) serves a wide scientific community with its variety of X-ray capabilities. Recently, we have employed a wiggler source located at beamline 10-2 to perform high resolution rocking curve imaging (RCI) of diamond and silicon crystals. In-house X-ray RCI capability is important for the upcoming cavity-based x-ray source development projects at SLAC, such as cavity-based XFEL (CBXFEL) and X-ray laser oscillator (XLO). In this proceeding, we describe theoretical considerations, and provide experimental results, validating the design of our apparatus. We also provide a plan for future improvements of the RCI@SSRL program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB096

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 10 August 2021

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MOPAB097

Two Color Grating design for Soft X-Ray Self-Seeding at LCLS-II

FEL, electron, simulation, laser

361

A. Halavanau, D. Cocco, E. Hemsing, G. Marcus, D.S. Morton
SLAC, Menlo Park, California, USA
G.R. Wilcox
Cornell University, Ithaca, New York, USA

A new grating design is examined for the soft x-ray self-seeding system (SXRSS) at LCLS-II to ultimately produce stable two-color XFEL pulses. The grating performance is analyzed with Fourier optics methods. The final XFEL performance is assessed via full numerical XFEL simulations that substantiate the feasibility of the proposed design.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB097

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 21 August 2021

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MOPAB120

Update on Injector for the New Synchrotron Light Source in Thailand

linac, storage-ring, synchrotron, injection

435

T. Chanwattana, S. Chunjarean, N. Juntong, K. Kittimanapun, S. Klinkhieo, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand
K. Manasatitpong
Synchrotron Light Research Institute (SLRI), Muang District, Thailand

Design of the new 3-GeV synchrotron light source in Thailand, Siam Photon Source II (SPS-II), has been updated. The SPS-II accelerator complex consists of a 150-MeV injector linac, a 3-GeV booster synchrotron and a 3-GeV storage ring. The RF system of both storage ring and booster is based on a frequency of 119 MHz. In this paper, design considerations and specifications of the SPS-II injector linac are presented. A study on the injector linac in multi-bunch mode (MBM) and single-bunch mode (SBM) was done to get appropriate parameters for top-up injection and different filling patterns in the storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB120

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paper received ※ 18 May 2021 paper accepted ※ 20 May 2021 issue date ※ 24 August 2021

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MOPAB126

BESSY III & MLS II - Status of the Development of the New Photon Science Facility in Berlin

undulator, radiation, lattice, emittance

451

P. Goslawski, M. Abo-Bakr, F. Andreas, M. Arlandoo, J. Bengtsson, V. Dürr, K. Holldack, J.-G. Hwang, A. Jankowiak, B.C. Kuske, J. Li, A.N. Matveenko, T. Mertens, A. Meseck, E.C.M. Rial, M. Ries, M.K. Sauerborn, A. Schälicke, M. Scheer, P. Schnizer, L. Shi, J. Viefhaus
HZB, Berlin, Germany
J. Lüning
UPMC, Paris, France

HZB operates and develops two synchrotron radiation sources at Berlin Adlershof. The larger one, BESSY II with an energy of 1.7 GeV and 240 m circumference is optimized for soft-X rays and in operation since 1999. The smaller one is the MLS (Metrology Light Source), owned by the Physikalische Technische Bundesanstalt (PTB) - Germany’s National Metrology Institute. It is designed to fulfill the special metrology needs of the PTB with an energy of 0.6 GeV and 48 m circumference, covering the spectral range from THz and IR to EUV/VUV. In 2020 a discussion process has been started to define the requirements for successors of BESSY II and MLS and to study the possibilities integrate them into a new photon science facility in Berlin Adlershof. Here, we give a status report and present a first envisaged parameter space to both machines (see also MOPAB262, MOPAB220, MOPAB048, MOPAB242).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB126

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paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 18 August 2021

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MOPAB131

Synchrotron SOLEIL Upgrade Project

lattice, emittance, vacuum, injection

463

A. Nadji
SOLEIL, Gif-sur-Yvette, France

To remain competitive in the future, SOLEIL is also working on an upgrade project plan based on Multi-Bend Achromat (MBA) lattices. The Technical Design Report of the project is expected to start in early 2021 immediately after the completion of the Conceptual Design Report (CDR) phase. The achieved equilibrium emittance in the CDR reference lattice (80 pm-rad) is about 50 times smaller than that of the existing storage ring (4000 pm-rad). By operating on a linear coupling resonance, round beam sizes in Insertion Devices straight sections of less than 10 microns RMS in both planes can be produced. These performances rely on the use of a 10 mm inner diameter circular copper vacuum chamber with NEG-coating allowing reaching strong quadrupole gradients and very strong sextupole and octupole strengths. As all these technical challenges are pushing the engineering technology to the limits, they are being investigated through an intensive R&D program based on extensive numerical simulations, prototyping, and measurement with the beam. Extensive use of the pure permanent magnet technology beyond what has been done so far in the other similar projects is considered in this project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB131

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paper received ※ 22 May 2021 paper accepted ※ 27 July 2021 issue date ※ 30 August 2021

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MOPAB240

Estimates of Damped Equilibrium Energy Spread and Emittance in a Dual Energy Storage Ring

emittance, storage-ring, damping, radiation

774

B. Dhital, G.A. Krafft
ODU, Norfolk, Virginia, USA
Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, and Office of Nuclear Physics under Contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. / Jefferson Lab EIC Fellowship2020.
A dual energy storage ring design consists of two loops at markedly different energies. As in a single-energy storage ring, the linear optics in the ring design may be used to determine the damped equilibrium emittance and energy spread. Because the individual radiation events in the two rings are different and independent, we can provide analytical estimates of the damping times in a dual energy storage ring. Using the damping times, the values of damped energy spread, and emittance can be determined for a range of parameters related to lattice design and rings energies. We present analytical calculations along with simulation results to estimate the values of damped energy spread and emittance in a dual energy storage ring. We note that the damping time tends to be dominated by the damping time of the high energy ring in cases where the energy of the high energy rings is significantly greater than that of the low energy ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB240

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paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 13 August 2021

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MOPAB279

Non-Invasive Beam Profile Monitoring for the HL-LHC Hollow Electron Lens

electron, proton, background, luminosity

884

A. Salehilashkajani, N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
M. Ady, N.S. Chritin, N. Jens, O.R. Jones, R. Kersevan, T. Lefèvre, S. Mazzoni, G. Papazoglou, A. Rossi, G. Schneider, R. Veness
CERN, Geneva, Switzerland
P. Forck, S. Udrea
GSI, Darmstadt, Germany
N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was supported by the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1 and the STFC Cockcroft core grant No. ST/G008248/1.
A Hollow Electron Lens (HEL) is currently under development for the High-Luminosity upgrade of the Large Hadron Collider (HL-LHC). In this device, a hollow electron beam co-propagates with a central proton beam and provides active halo control in the LHC. To ensure the concentricity of the two beams, a non-invasive diagnostic instrument is currently being commissioned. This instrument is a compact version of an existing prototype that leverages beam induced fluorescence with supersonic gas curtain technology. This contribution includes the design features of this version of the monitor, recent progress, and future plans for tests at the Cockcroft Institute and the electron lens test stand at CERN.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB279

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 02 September 2021

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MOPAB296

Statistical Analysis of 2D Single-Shot PPRE Bunch Measurements

radiation, operation, diagnostics, storage-ring

939

M. Koopmans, J.-G. Hwang, A. Jankowiak, M. Ries, A. Schälicke, G. Schiwietz
HZB, Berlin, Germany

The pulse picking by resonant excitation (PPRE) method* is used to realize pseudo single-bunch radiation from a complex filling pattern at the BESSY II storage ring. The PPRE bunch is excited in the horizontal plane by a quasi-resonant incoherent perturbation to increase the emittance of this bunch**. Therefore, the synchrotron light of the PPRE bunch can be separated by collimation from the radiation of the main bunch train at dedicated beamlines for timing users. The properties of the PPRE bunch depend on the storage ring settings and on the excitation parameters. It is not trivial to distinguish between the wanted intrinsic bunch broadening and an additional position fluctuation of the PPRE bunch. Using the potential of the new diagnostics beamline with the possibility to observe an additional spatial dimension with a fast streak camera, we introduce a new method to study the properties of the PPRE bunch***. Applying a statistical analysis to a series of single-turn images enables distinguishing between horizontal orbit motion and the broadening of the bunch due to the excitation. Measurements are presented and the results are compared with data from the BPM system.
* K. Holldack et al., Nature Commun. 5 (2014) 4010.
** J.-G. Hwang et al., Nucl. Instrum. Methods A940 (2019) 387.
*** G. Schiwietz et al., Nucl. Instrum. Methods A990 (2021) 164992.

Poster MOPAB296 [2.074 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB296

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 23 August 2021

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MOPAB303

Design of the X-Ray Beam Size Monitor for the Advanced Photon Source Upgrade

emittance, electron, detector, storage-ring

956

K.P. Wootton, F.K. Anthony, K. Belcher, J.S. Budz, J. Carwardine, W.X. Cheng, S. Chitra, G. Decker, S.J. Izzo, S.H. Lee, J. Lenner, Z. Liu, P. McNamara, H.V. Nguyen, F.S. Rafael, C. Roehrig, J. Runchey, N. Sereno, G. Shen, J.B. Stevens, B.X. Yang
ANL, Lemont, Illinois, USA

Funding: This research used resources of the Advanced Photon Source, operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.
A beam size monitor provides an intuitive display of the status of the beam profile and motion in an accelerator. In the present work, we outline the design of the X-ray electron beam size monitor for the Advanced Photon Source Upgrade. Components and anticipated performance characteristics of the beam size monitor are outlined.

Poster MOPAB303 [0.577 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB303

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 24 August 2021

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MOPAB328

Beam Instrumentation for Linear Accelerator of SKIF Synchrotron Light Source

electron, diagnostics, radiation, simulation

1016

X.C. Ma
BINP, Novosibirsk, Russia
M.V. Arsentyeva, E.A. Bekhtenev, V.M. Borin, G.V. Karpov, Yu.I. Maltseva, O.I. Meshkov, D.A. Nikiforov, O.A. Pavlov, V.G. Tcheskidov, V. Volkov
BINP SB RAS, Novosibirsk, Russia
M.V. Arsentyeva, E.A. Bekhtenev, V.M. Borin, Yu.I. Maltseva, O.I. Meshkov, D.A. Nikiforov
NSU, Novosibirsk, Russia
V.M. Borin
NSTU, Novosibirsk, Russia

A new synchrotron light source SKIF of the 4th generation is under construction at BINP SB RAS (Novosibirsk, Russia). The linear accelerator is SKIF’s injector to provide 200 MeV electron beam. The set of diagnostics will be applied for tuning of the linear accelerator and measurements of beam parameters from electron RF gun to output of the accelerator. It includes 8 fluorescent screens for the beam transverse dimensions measurement, 2 Cherenkov probes for the beam duration measurement, magnetic spectrometer with range from 0.6 to 200 MeV, and some beam charge and current measurement devices, as Faraday cup, FCT, BPM along linear accelerator. Numerical simulations of diagnostics elements and results of beam dynamics simulations are introduced in paper. Brief description of the design and parameters of each diagnostics system is presented. Possible scenarios of linear accelerator tuning are also discussed.

Poster MOPAB328 [2.324 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB328

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paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 31 August 2021

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MOPAB380

Status and Progress of the RF System for High Energy Photon Source

cavity, storage-ring, booster, low-level-rf

1165

P. Zhang, J. Dai, Z.W. Deng, L. Guo, T.M. Huang, D.B. Li, J. Li, Z.Q. Li, H.Y. Lin, Y.L. Luo, Q. Ma, F. Meng, Z.H. Mi, Q.Y. Wang, X.Y. Zhang, F.C. Zhao, H.J. Zheng
IHEP, Beijing, People’s Republic of China

Funding: This work was supported in part by High Energy Photon Source, a major national science and technology infrastructure in China and in part by the Chinese Academy of Sciences.
High Energy Photon Source (HEPS) is a 6 GeV diffraction-limited synchrotron light source currently under construction in Beijing. It adopts a double-frequency RF system with 166.6 MHz as fundamental and 499.8 MHz as third harmonic. The fundamental cavity is making use of a superconducting quarter-wave β=1 structure and the third harmonic is of superconducting elliptical single-cell geometry for the storage ring, while normal-conducting 5-cell cavities are chosen for the booster ring. A total of 900 kW RF power shall be delivered to the beam by the 166.6 MHz cavities and the third harmonic cavities are active. All cavities are driven by solid-state power amplifiers and the RF fields are regulated by digital low-level RF control systems. The cavity and ancillaries, high-power RF system and low-level RF control system are in the prototyping phase. This paper presents the current status and progress of the RF system for HEPS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB380

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paper received ※ 09 May 2021 paper accepted ※ 09 June 2021 issue date ※ 24 August 2021

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MOPAB390

Development of a 166.6 MHz Low-Level RF System by Direct Sampling for High Energy Photon Source

cavity, LLRF, controls, pick-up

1189

D.B. Li, H.Y. Lin, Q.Y. Wang, P. Zhang
IHEP, Beijing, People’s Republic of China

Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China.
A digital low-level radio frequency (LLRF) system by direct sampling has been proposed for 166.6 MHz superconducting cavities at High Energy Photon Source (HEPS). The RF field inside the cavities has to be controlled better than ±0.1% (peak to peak) in amplitude and ±0.1 deg (peak to peak) in phase. Considering that the RF frequency is 166.6 MHz, which is well within the analog bandwidth of modern high-speed ADCs and DACs, direct RF sampling and direct digital modulation can be achieved. A digital LLRF system utilizing direct sampling has therefore been developed with embedded experimental physics and industrial control system (EPICS) in the field programmable gate array (FPGA). The performance in the lab has been characterized in a self-closed loop with a residual peak-to-peak noise of ±0.05% in amplitude and ±0.03 deg in phase, which is well below the HEPS specifications. Further tests on a warm 166.6 MHz cavity in the lab are also presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB390

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021

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MOPAB405

Study of Targets to Produce Molybdenum-99 Using 30 MeV Electron Linear Accelerator

target, electron, radiation, linac

1222

T.S. Dixit, A.P. Deshpande, R. Krishnan, A. Shaikh
SAMEER, Mumbai, India

Funding: Ministry of Electronics and Information Technology, Government of India (MeitY)
Two approaches to produce 99Mo are studied using GEANT4 are reported in this paper. First, in converter target approach, bremsstrahlung photons are generated in a high Z target. The emitted photons then hit 100Mo secondary target, producing 99Mo through (gamma, n) reaction. Second, in direct target approach, high energy electron beam hits 100Mo target, where both (e, gamma) and (gamma, n) reactions take place simultaneously. A 30 MeV, 5-10 kW beam power electron linac is under development at SAMEER. The acceleration gradient required to achieve 30 MeV energy will be provided by two linacs operated in series configuration and the high average beam power will be achieved by running the system at high duty operation. Main aim of this study is to optimize experimental parameters to maximize specific activity of 99Mo. Since, 100Mo is very expensive material therefore judicious use of the material is very important. Hence, optimization of electron beam energy and target dimensions are studied in detail in both the approaches. It is found that the direct target approach gives higher specific activity compared to the converter target approach.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB405

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paper received ※ 19 May 2021 paper accepted ※ 06 June 2021 issue date ※ 14 August 2021

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MOPAB409

FLUKA Simulations of ²²⁵Ac Production Using Electron Accelerators: Validation Through Comparison with Published Experiments

electron, experiment, target, radiation

1226

T.V. Szabo, I.C. Moraes
CNPEM, Campinas, SP, Brazil
F.A. Bacchim Neto
LNLS, Campinas, Brazil
P.V. Guillaumon
USP/LAL, Sao Paulo, Brazil
H.B. de Oliveira
IPEN, São Paulo, Brazil

Targeted Alpha Therapy (TAT) is an active area of study worldwide. This technique has shown a potential in nuclear medicine to treat metastatic disease by alpha particles that deposit energy in small regions nearby cancer cells. Ac-225 is an important alpha-emitting that can be used for cancer TAT. This radioisotope shows good potential for medical applications, therefore is important to study ways of increase its production and availability. One possible path for the Ac-225 product is to radiate a radium target (Ra-226) on a linear electron accelerator (LINAC). Isotope production studies could be implemented using computational tools. In this work, Monte Carlo simulations with FLUKA code were performed and compared to experimental results *. We studied Ac-225 production by photonuclear reactions using a 24 MeV electron beam LINAC hitting a tungsten electron-photon converter. Different energies and geometries were also simulated to obtain optimal production conditions. The specific activity values obtained with simulations had a good agreement with published experimental results.
* MASLOV, O., et. al. Preparation of 225Ac by 226Ra(g, n) photonuclear reaction on an mt25 microtron. Radiochemistry

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB409

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021

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TUPAB027

Review of Accelerator Limitations and Routes to Ultimate Beams

collider, acceleration, electron, luminosity

1397

F. Zimmermann
CERN, Geneva, Switzerland
R.W. Aßmann
DESY, Hamburg, Germany
M. Bai, G. Franchetti
GSI, Darmstadt, Germany

Funding: This work was supported in part by the European Commission under the HORIZON 2020 project I.FAST, no. 101004730.
Various physical and technology-dependent limits are encountered for key performance parameters of accelerators such as high-gradient acceleration, high-field bending, beam size, beam brightness, beam intensity and luminosity. This paper will review these limits and the associated challenges. Possible figures-of-merit and pathways to ultimate colliders will also be explored.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB027

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paper received ※ 16 May 2021 paper accepted ※ 02 August 2021 issue date ※ 23 August 2021

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TUPAB046

Preliminary design of the Full Energy Linac Injector for the Southern Advanced Photon Source

linac, FEL, gun, injection

1454

X. Liu
Institute of High Energy Physics, CAS, Guangdong, People’s Republic of China
Y. Jiao, B. Li, S. Wang
IHEP, Beijing, People’s Republic of China

A 4th generation mid-energy range diffraction limited storage ring, named as the Southern Advanced Photon Source (SAPS), is under consideration to be built at the same campus as China Spallation Neutron Source (CSNS), providing a charming one-stop solution for fundamental sciences and industrial applications. While the design of the ring is still under study, a full energy Linac has been proposed as one candidate option for its injector, with the capability of being used as an X-ray Free Electron Laser (XFEL) in the near future. In this paper, an overview of the preliminary design of the Linac is given and simulation results are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB046

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paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 10 August 2021

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TUPAB052

Current Study of Applying Machine Learning to Accelerator Physics at IHEP

network, electron, lattice, target

1477

J. Wan, Y. Jiao
IHEP, Beijing, People’s Republic of China

Funding: National Natural Science Foundation of China(No.11922512), Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y201904) and National Key R&D Program of China(No.2016YFA0401900).
In recent years, machine learning (ML) has attracted increasing interest among the accelerator field. As a complex collection of multiple physical subsystems, the design and operation of an accelerator can be very nonlinear and complicated, while ML is taken as a powerful tool to solve such nonlinear and complicated problems. In this study, we report on several successful applications of ML to accelerator physics at IHEP. The nonlinear dynamics optimization of the High Energy Photon Source (HEPS) that is a 4th-generation light source is a challenging topic. In this optimization, we use a ML surrogate model to fast select the potentially competitive solutions for a multiobjective genetic algorithm that can significantly improve the convergence rate and the diversity among obtained solutions. Besides, we also tried to apply a generative adversarial net to solve one-to-many problems of longitudinal beam current profile shaping. Unlike most supervised machine learning methods than cannot learn one-to-many maps, the generative adversarial net-based method is able to predict multiple solutions instead of one for a 4-dipole chicane to realize several desired custom current profiles.

Poster TUPAB052 [0.913 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB052

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paper received ※ 11 May 2021 paper accepted ※ 21 June 2021 issue date ※ 27 August 2021

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TUPAB054

CDR BASELINE LATTICE FOR THE UPGRADE OF SOLEIL

lattice, emittance, injection, coupling

1485

A. Loulergue, D. Amorim, P. Brunelle, A. Gamelin, A. Nadji, L.S. Nadolski, R. Nagaoka, R. Ollier, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Previous MBA studies converged toward a lattice composed of 20 7BA solution elaborated by adopting the sextupole pairing scheme with dispersion bumps originally developed at the ESRF-EBS. It provided a low natural horizontal emittance value of 70-80 pm-rad range at an energy of 2.75 GeV. Due to difficulties to accommodate such lattice geometry in the SOLEIL present tunnel as well as to preserve at best the beamline positioning, alternative lattice based on HOA (Higher-Order Achromat) type cell has been recently investigated. The HOA type cell being more modular and possibly exhibiting larger momentum acceptance as well as low emittances, a solution alternating 7BA and 4BA cells was then identified as the best to adapt the current beamline positioning. The SOLEIL CDR upgrade reference lattice is then composed of 20 HOA cells alternating 7BA and 4BA giving a natural horizontal emittance of 80 pm-rad. The linear and non-linear beam dynamic properties of the lattice along with the possibility of horizontal off-axis injection at full betatron coupling are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB054

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paper received ※ 21 May 2021 paper accepted ※ 02 July 2021 issue date ※ 10 August 2021

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TUPAB058

Online Optimizations of Several Observable Parameters at the Advanced Photon Source

injection, storage-ring, kicker, sextupole

1492

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Online optimizations are known to be powerful tools which may quickly and efficiently improve the particle accelerator key performance parameters in a model-independent way. In this paper, it is presented on the online optimizations of several observable parameters at the Advanced Photon Source storage ring. These observable parameters include the beam lifetime, injection efficiency and topup efficiency, transverse beam sizes, and turn by turn beam position monitors. It is demonstrated that the particle accelerator performance may be greatly enhanced in a relatively short time frame, by optimizing these observable parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB058

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paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 16 August 2021

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TUPAB060

Machine Learning on Beam Lifetime and Top-Up Efficiency

network, operation, storage-ring, emittance

1499

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Both unsupervised and supervised machine learning techniques are employed for automatic clustering, modeling and prediction of Advanced Photon Source (APS) storage ring beam lifetime and top-up efficiency archived in operations. The naive Bayes classifier algorithm is developed and combined with k-means clustering to improve accuracy, where the unsupervised clustering of APS beam lifetime and top-up efficiency is consistent with either true label from data archive or Gaussian kernel density estimation. Artificial neural network algorithms have been developed, and employed for training and modelling the arbitrary relations of beam lifetime and top-up efficiency on many observable parameters. The predictions from artificial neural network reasonably agree with the APS operation data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB060

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paper received ※ 22 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021

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TUPAB061

Anomaly Detection by Principal Component Analysis and Autoencoder Approach

network, operation, power-supply, storage-ring

1502

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Several different approach are employed to identify the abnormal events in some Advanced Photon Source (APS) operation archived dataset, where dimensionality reduction are performed by either principal component analysis or autoencoder artificial neural network. It is observed that the APS stored beam dump event, which is triggered by magnet power supply fault, may be predicted by analyzing the magnets capacitor temperatures dataset. There is reasonable agreement among two principal component analysis based approaches and the autoencoder artificial neural network approach, on predicting future overall system fault which may result in a stored beam dump in the APS storage ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB061

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paper received ※ 22 May 2021 paper accepted ※ 18 June 2021 issue date ※ 19 August 2021

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TUPAB069

The Sabina Terahertz/Infrared Beamline at SPARC-Lab Facility

radiation, electron, experiment, laser

1525

S. Macis
La Sapienza University of Rome, Rome, Italy
M. Bellaveglia, M. Cestelli Guidi, E. Chiadroni, F. Dipace, A. Ghigo, L. Giannessi, A. Giribono, L. Sabbatini, C. Vaccarezza
INFN/LNF, Frascati, Italy
A. Doria, A. Petralia
ENEA C.R. Frascati, Frascati (Roma), Italy
S. Lupi
Sapienza University of Rome, Roma, Italy
V. Petrillo
INFN-Milano, Milano, Italy

Funding: SABINA is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program.
Following the EU Terahertz (THz) Road Map*, high-intensity, ps-long, THz)/Infrared (IR) radiation is going to become a fundamental spectroscopy tool for probing and control low-energy quantum systems ranging from graphene, and Topological Insulators, to novel superconductors** ***. In the framework of the SABINA project, a novel THz/IR beamline based on an APPLE-X undulator emission will be developed at the SPARC-Lab facility at LNF-INFN. Light will be propagated from the SPARC-Lab to a new user lab facility nearly 20 m far away. This beamline will cover a broad spectral region from 3 THz to 30 THz, showing ps- pulses and energy of tens of µJ with variable polarization from linear to circular. The corresponding electric fields up to 10 MV/cm, are able to induce non-linear phenomena in many quantum systems. The beamline, open to user experiments, will be equipped with a 5 T magnetic cryostat and will be synchronized with a fs laser for THz/IR pump, VIS/UV probe experiments.
[*] S.S. Dhillon et al., J. Phys. D: Appl. Phys. 50, 043001 (2017);
[**] F. Giorgianni et al., Nature Commun. 7, 11421 (2016);
[***] P. Di Pietro et al., Phys. Rev. Lett. 124, 226403 (2020);

Poster TUPAB069 [0.884 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB069

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paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 25 August 2021

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TUPAB104

Redesign of the FLASH2 Post-SASE Undulator Beamline

undulator, electron, quadrupole, MMI

1626

F. Christie, J. Rönsch-Schulenburg, S. Schreiber, M. Vogt, J. Zemella
DESY, Hamburg, Germany

FLASH2 is one of the two SASE (Self-Amplified Spontaneous Emission) undulator beamlines lines comprising variable gap undulators to produce radiation in the XUV and soft X-ray regime at FLASH. Downstream of the SASE undulators the beamline is currently undergoing a major redesign. During shutdowns in summer 2020 and winter 2021 two PolariX TDSs (Polarizable X-band Transverse Deflecting Structure) were installed, as well as additional diagnostics, to monitor the longitudinal phase space density of the electron bunches. Additionally, an afterburner undulator will be integrated in the next shutdown to produce circularly polarized light with wavelengths down to 1.39 nm. In this paper, we will present the modifications that were and will be made to the electron beamline in the course of this redesign.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB104

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paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 23 August 2021

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TUPAB114

FEL Performance and Beam Quality Assessment of Undulator Line for the CompactLight Facility.

undulator, FEL, brilliance, electron

1655

H.M. Castañeda Cortés, D.J. Dunning, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: H2020 CompactLight has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 777431
The H₂020 CompactLight Project aims for the design of innovative, cost-effective, compact FEL facilities to generate higher peak brilliance radiation in the soft and hard X-ray. In this paper we assess via simulation studies the performance of a variably polarising APPLE-X afterburner positioned downstream of a helical Super Conducting Undulator (SCU). We discuss the optimum balance between the active SCU length and the afterburner length, considering the peak brilliance and pulse energy of the output. Our studies are complemented with analysis of the optical beam quality of the afterburner output to determine the design constraints of the photon beamline that delivers the FEL output to the experimental areas.
* Mak, A., Salen, P., Goryashko, V., Clarke, J., http://uu.diva-portal.org/smash/record.jsf?pid=diva2\%3A1280300&dswid=3236
** Lutman, A. et al. Nature Photonics 10, 468

Poster TUPAB114 [1.210 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB114

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paper received ※ 11 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021

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TUPAB141

On the Development of a Low Peak-Power, High Repetition-Rate Laser Plasma Accelerator at IPEN

laser, plasma, electron, experiment

1713

A. Bonatto
Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
E.P. Maldonado
ITA, São José dos Campos, Brazil
R.P. Nunes
UFRGS, Porto Alegre, Brazil
R.E. Samad, F.B.D. Tabacow, N.D. Vieira, A.V.F. Zuffi
IPEN-CNEN/SP, São Paulo, Brazil

Funding: FAPESP (Grant #2018/25961), CNPq and CAPES.
In this work, the current status on the development of a laser plasma accelerator at the Nuclear and Energy Research Institute (Instituto de Pesquisas Nucleares e Energéticas, IPEN/CNEN), in São Paulo, Brazil, is presented. Short pulses to be produced by an under-development near-TW, kHz laser system will be used to ionize a gas jet, with a density profile designed to optimize the self-injection of plasma electrons. The same laser pulse will also drive a plasma wakefield, which will allow for electron acceleration in the self-modulated regime. The current milestone is to develop the experimental setup, including electron beam and plasma diagnostics, required to produce electron bunches with energies of a few MeV. Once this has been achieved, the next milestone is to produce beams with energies higher than 50 MeV. Besides kickstarting the laser wakefield accelerator (LWFA) technology in Brazil, this project aims to pave the way for conducting research on the production of radioisotopes by photonuclear reactions, triggered by LWFA-accelerated beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB141

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 10 August 2021

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TUPAB246

Numerical Simulation and Beam-Dynamics Study of a Hollow-Core Woodpile Coupler for Dielectric Laser Accelerators

GUI, laser, acceleration, electron

2022

G.S. Mauro, D. Mascali, G. Sorbello, G. Torrisi
INFN/LNS, Catania, Italy
A. Bacci
INFN/LASA, Segrate (MI), Italy
C. De Angelis, A. Locatelli
University of Brescia, Brescia, Italy
A.R. Rossi
INFN-Milano, Milano, Italy
G. Sorbello
University of Catania, Catania, Italy

Hollow core dielectric microstructures powered by lasers represent a new and promising area of accelerator research thanks to the higher damage threshold and accelerating gradients with respect to metals at optical wavelengths. In this paper we present the design of a dielectric Electromagnetic Band Gap (EBG) mode converter for high-power coupling of the accelerating mode in Dielectric Laser Accelerators (DLAs). The design is wavelength-independent, and here we propose an implementation operating at 90.505 GHz (wavelength 3.3 mm) based on a silicon woodpile structure. The coupler is composed by two perpendicularly coupled hollow-core waveguides: a TE-like mode waveguide (excited from RF/laser power) and a TM-like mode accelerating waveguide. The structure has been numerically designed and optimized, presenting Insertion Losses (IL) < 0.3 dB and an efficient mode conversion in the operating bandwidth. The properties and effectiveness of the confined accelerating mode have been optimized in order to derive the needed accelerating gradient. The simulated electric field has been used as input for Astra beam-dynamics simulations in order to compute the beam properties.

Poster TUPAB246 [2.209 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB246

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paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 13 August 2021

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TUPAB287

Application of Artificial Neural Network in the APS Linac Bunch Charge Transmission Efficiency

linac, operation, kicker, controls

2155

H. Shang, R. Maulik, Y. Sun
ANL, Lemont, Illinois, USA
T. Xu
Northern Illinois University, DeKalb, Illinois, USA

Funding: * Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
In recent years there has been a rapid growth in machine learning (ML) and artificial intelligence (AI) applications in accelerators. As the scale of complexity and sophistication of modern accelerators grows, the difficulties in modeling the machine increase greatly in order to include all the interacting subsystems and to consider the limitation of various diagnostics to benchmark against measurements. Tools based on ML can help substantially in revealing correlations of machine condition and beam parameters that are not easily discovered using traditional physics model-based simulations, reducing machine tuning up time etc among the many possible applications. While at APS we have many excellent tools for the optimization, diagnostics, and controls of the accelerators, we do not yet have ML-based tools established. It is our desire to test ML in our machine operation, optimization, and controls. In this paper, we introduce the application of neural networks to the APS linac bunch charge transmission efficiency.

Poster TUPAB287 [0.781 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB287

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paper received ※ 12 May 2021 paper accepted ※ 16 June 2021 issue date ※ 29 August 2021

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TUPAB290

Demonstration of Machine Learning Front-End Optimization of the Advanced Photon Source Linac

linac, controls, gun, electron

2163

A. Hanuka, J.P. Duris
SLAC, Menlo Park, California, USA
H. Shang, Y. Sun
ANL, Lemont, Illinois, USA

The electron beam for the Advanced Photon Source (APS) at Argonne National Laboratory is generated from a thermionic RF gun and accelerated by an S-band linear accelerator – the APS linac. While the APS linac lattice is set up using a model developed with ELEGANT, the thermionic RF gun front-end beam dynamics have been difficult to model. One of the issues is that beam properties from thermionic guns can vary. As a result, linac front-end beam tuning is required to establish good matching and maximize the charge transported through the linac. A traditional Nelder-Mead simplex optimizer has been used to find the best settings for the sixteen quadrupoles and steering magnets. However, it takes a long time and requires some fair initial conditions. The Gaussian Process (GP) optimizer does not have the initial condition limitation and runs several times faster. In this paper, we report our data collection and analysis for the training of the GP hyperparameters and discuss the application of GP optimizer on the APS linac front-end optimization for maximum bunch charge transportation efficiency through the linac.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB290

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paper received ※ 09 May 2021 paper accepted ※ 28 July 2021 issue date ※ 27 August 2021

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TUPAB316

New Operational Quantities for Radiation Protection by ICRU and ICRP: Impact on Workplaces at Accelerators

radiation, operation, MMI, target

2231

Th. Otto, M. Widorski
CERN, Meyrin, Switzerland

In radiation protection, Effective Dose E quantifies stochastic radiation detriment. E is defined as a weighted sum of absorbed dose to organs and tissues and cannot be measured directly. ICRU has defined operational quantities to measure effective dose approximately, such as Ambient dose equivalent H*(10). At high energies, the estimates provided by H*(10) deviate strongly from effective dose. In 2020, ICRU and ICRP have recommended new operational quantities for external radiation with a definition close to the one of effective dose, and published an extensive collection of conversion coefficients from particle fluence to the new quantities (1). Ambient dose H* serves for operational monitoring purposes. The new definition alleviates the observed discrepancies of H*(10) with effective dose. In this paper, we present a numerical study of effective dose E, ambient dose equivalent H*(10) and ambient dose H* in radiation fields at workplaces at proton- and electron accelerators. These places include locations behind primary shielding, in access mazes and in the vicinity of activated accelerator components.
(1) ICRU Report 95, Operational quantities for external radiation

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB316

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paper received ※ 11 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021

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TUPAB318

The Beamline Safety Interlock System of Taiwan Photon Source

radiation, vacuum, controls, synchrotron-radiation

2239

C.F. Chang, C.Y. Chang, C.Y. Liu, H.Y. Yan
NSRRC, Hsinchu, Taiwan

The energy of synchrotron radiation generated by bremsstrahlung radiation and magnet is rather high, which may cause serious radiation damage to human body or even imperil people’s life. The beamline therefore must be equipped with radiation-protection system; in addition, the overheat of optical components exposed to synchrotron radiation will lead to the damage of optical components and devices. In consequence, the beamline should be furnished with the cooling-protection system to cool down optical components and devices. The Beamline Safety Interlock System targets at protecting the personnel and the safety of devices, limiting the radiation dose to a security value for experimental personnel or staffs exposing to radiation on the site as well as preventing beamline components from being exposed to overheat or vacuum damages to improve the effectiveness of beamline.

Poster TUPAB318 [3.440 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB318

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paper received ※ 09 May 2021 paper accepted ※ 10 June 2021 issue date ※ 31 August 2021

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TUPAB340

Design of the Magnetic Shielding for 166 MHz and 500 MHz Superconducting RF Cavities at High Energy Photon Source

cavity, shielding, simulation, superconducting-cavity

2289

L. Guo, Y. Chen, J. Li, Z.Q. Li, Q. Ma, P. Zhang, X.Y. Zhang, H.J. Zheng
IHEP, Beijing, People’s Republic of China

Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China.
Five 166 MHz quarter-wave β=1 superconducting cavities and two 500 MHz single-cell elliptical superconducting cavities have been designed for the storage ring of High Energy Photon Source (HEPS). It is necessary to shield magnetic field for superconducting cavities to reduce the residual surface resistance due to magnetic flux trapping during cavity cool down. The magnetic shielding for both 166 MHz and 500 MHz superconducting cavities have been designed. The residual magnetic field inside the cavities have been calculated by using Opera-3D simulation software. The geographic location of the cavity being installed at the HEPS site and the fringe field of the upstream magnet are considered. These are reported in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB340

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 10 August 2021

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TUPAB346

Development of a 500-MHz 150-kW Solid-State Power Amplifier for High Energy Photon Source

GUI, cavity, controls, booster

2312

Y.L. Luo, T.M. Huang, J. Li, H.Y. Lin, Q. Ma, Q.Y. Wang, P. Zhang, F.C. Zhao
IHEP, Beijing, People’s Republic of China

A 500-MHz 150-kW solid-state power amplifier (SSA) has been developed to test the 500-MHz normal conducting cavities for High Energy Photon Source (HEPS) booster ring. It will also be used to power normal conducting cavities in the initial beam commissioning stage of the HEPS storage ring. A total number of 96 amplifier modules are combined initially by coaxial and later by waveguide combiners to deliver the 150-kW RF power. The final output is of EIA standard WR1800 rectangular waveguide. Each amplifier module consists four transistors equipped with individual circulator and load and outputs 2-kW RF power. Modularity, redundancy and satisfactory RF performance are demonstrated. In the final stage of HEPS project, this 150-kW amplifier will be modified to a 100-kW amplifier to join the other five 100-kW SSAs for normal operation of the booster cavities. The development and test results are presented in this paper.

Poster TUPAB346 [1.870 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB346

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 15 August 2021

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TUPAB347

Development of a 166-MHz 260-kW Solid-State Power Amplifier for High Energy Photon Source

controls, status, power-supply, cavity

2315

Y.L. Luo, T.M. Huang, J. Li, H.Y. Lin, Q. Ma, Q.Y. Wang, P. Zhang, F.C. Zhao
IHEP, Beijing, People’s Republic of China

166-MHz 260-kW solid-state power amplifiers have been chosen to drive the 166.6-MHz superconducting cavities for the storage ring of High Energy Photon Source. Highly modular yet compact are desired. A total number of 112 amplifier modules of 3 kW each are combined in a multi-stage power combining topology. The final output is of 9-3/16" 50 Ω coaxial rigid line. Each amplifier module consists of 3 LDMOS transistors with individual circulator and load. Thermal simulations of the amplifier module have been conducted to optimize cooling capabilities for both travelling-wave and full-reflection operation scenarios. High efficiency, sufficient redundancy and excellent RF performances of the 260-kW system are demonstrated. A control system is also integrated and EPICS is used to manage the monitored data. The design and test results of the amplifier system are presented in this paper.

Poster TUPAB347 [1.972 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB347

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 29 August 2021

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TUPAB373

Design of a Delta-type Superconducting Undulator at the IHEP

undulator, polarization, permanent-magnet, radiation

2391

J.H. Wei
IHEP CSNS, Guangdong Province, People’s Republic of China
C.D. Deng
DNSC, Dongguan, People’s Republic of China
L. Gong, X.Y. Li, X.C. Yang
IHEP, Beijing, People’s Republic of China
Y. Li
DESY, Hamburg, Germany

Undulators play an important role in the 4th generation radiation light source. In order to satisfy different requirements of the experiments, various undulator structures have been proposed. The Delta-type undulator can provide circular polarized radiation. Conventional undulators are usually made of permanent magnets, but the application of the superconducting technology in the undulator is developing quickly. Compared to the permanent magnet undulators, superconducting undulators can provide higher photon flux with the same magnetic pole gap and period length, especially when the period length is longer than 20 mm. An R&D project is underway to produce a protype of a Delta-type superconducting undulator with 28 mm long period and 12 mm gap at the IHEP. The structure design and the simulation results of the magnetic field are presented in this paper.

Poster TUPAB373 [1.752 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB373

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 15 August 2021

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TUPAB375

Commissioning and Operation of Superconducting Multipole Wiggler at Siam Photon Source

MMI, operation, wiggler, electron

2398

P. Sunwong, S. Boonsuya, S. Chaichuay, T. Chanwattana, Ch. Dhammatong, A. Kwankasem, C.P. Preecha, T. Pulampong, K. Sittisard, V. Sooksrimuang, S. Srichan, P. Sudmuang, N. Suradet, S. Tancharakorn
SLRI, Nakhon Ratchasima, Thailand

A new insertion device, Superconducting Multipole Wiggler (SMPW) with the peak field strength of 3.5 T, was installed in the storage ring of Siam Photon Source as a radiation source for a new hard X-ray beamline. Cool-down process, as well as magnet training, was performed with careful tuning of liquid helium filling procedure for efficient management of liquid helium supply. The filling procedure was also optimized for safe operation of the magnet. The SMPW commission-ing was successfully carried out with electron beam and the effect of SMPW on electron beam dynamics was observed. It can be minimized using quadrupole magnets and horizontal/vertical correctors.

Poster TUPAB375 [1.160 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB375

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 31 August 2021

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TUPAB392

Conceptual Design of the Vacuum System for the Future Circular Collider FCC-ee Main Rings

vacuum, collider, quadrupole, scattering

2438

R. Kersevan, C. Garion
CERN, Geneva, Switzerland

The Future Circular Collider study program comprises several machine concepts for the future of high-energy particle physics. Among them there is a twin-ring e⁻e⁺ collider capable to run at beam energies between 45.6 and 182.5 GeV, i.e. the energies corresponding to the resonances of the Z, W, H bosons and the top quark. The conceptual design of the two 100-km rings has advanced to what is believed to be a working solution, i.e. capability to deal with low-energy (45.6 GeV) high-current (1390 mA) version as well as the high-energy (182.5 GeV) low-current (5.4 mA) one, with intermediate energy and current steps for the other 2 resonances. The limit for all of the versions is given by the 50 MW/beam allotted to the synchrotron radiation (SR) losses. The paper will outline the main beam/machine parameters, the vacuum requirements, and the choices made concerning the vacuum chamber geometry, material, surface treatments, pumping system, and the related pressure profiles. The location of lumped SR photon absorbers for the generic arc cell has been determined. An outline of the studies needed and envisaged for the near future will also be given.

Poster TUPAB392 [3.036 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB392

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 25 August 2021

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TUPAB404

Monte Carlo Studies for Shielding Design for High Energy Linac for Medical Isotope Generation

neutron, shielding, radiation, target

2469

N. Upadhyay, S. Chacko
University of Mumbai, Mumbai, India
A.P. Deshpande, T.S. Dixit, P.S. Jadhav, R. Krishnan
SAMEER, Mumbai, India

The widely used radioactive tracer Technetium-99m (99mTc) is traditionally produced from Uranium via 235U (n, f) 99Mo reactions which depends heavily on nuclear reactors. Design studies for an alternative, cleaner approach for radioisotope generation using a high energy electron linac were initiated at SAMEER to generate 99Mo. The electron beam from a 30 MeV linac with an average current of 350 µA will be bombarded on a convertor target to produce X-rays which will be bombarded on enriched 100Mo target to produce 99Mo via (g, n) reaction. 99mTc will be eluted from 99Mo. The photons and neutrons produced in the process should be shielded appropriately to ensure radiation safety. This paper brings out the use of Monte Carlo techniques for photon and neutron shielding for our application. We used FLUKA to calculate the fluence, angular distribution and dose for photons and neutrons. Then, we introduced various layers of lead followed by HDPE, 5% borated HDPE and 40% boron rubber to ensure that the proposed shielding is sufficient to completely shield the photon as well as neutron radiation and hence is safe for operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB404

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paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 25 August 2021

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TUPAB409

FLUKA and Geant4 Monte Carlo Simulations of a Desktop, Flat Panel Source Array for 3D Medical Imaging

simulation, electron, experiment, detector

2483

T. Primidis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
T. Primidis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
V. Soloviev
Adaptix Imaging, Didcot, United Kingdom

Funding: Funded by the Accelerators for Security, Healthcare and Environment CDT from the United Kingdom Research and Innovation Science and Technology Facilities Council, reference ID ST/R002142/1
Digital tomosynthesis (DT) is a 3D imaging modality with a lower cost and lower dose than computed tomography. A DT system made of a flat panel array with 45 X-ray sources, but compact enough to fit on the desktop is near market realisation by the company Adaptix Ltd. This work presents a framework of FLUKA and Geant4 Monte Carlo (MC) simulations of the Adaptix system including the X-ray beam generation and the final image quality. The results show that MC methods offer an insight into the performance details of such an innovative device at different levels between the X-ray emitter array and the detector. As such, a large portion of the design and optimisation of such novel X-ray imaging systems can be done with a single toolkit. Finally, the modularity of the approach allows other tools to be imported at various steps within the framework and thus provide answers to questions that cannot be addressed by general-purpose MC codes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB409

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 24 August 2021

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TUPAB410

Finite Element Analysis and Experimental Validation of Low-Pressure Beam Windows for XCET Detectors at CERN

experiment, Windows, detector, background

2487

J. Buesa Orgaz, M. Brugger, G. Romagnoli, O. Sacristan De Frutos, F. Sanchez Galan
CERN, Meyrin, Switzerland

In the framework of the renovation and consolidation of experimental areas at CERN, a low-pressure design beam superimposed windows (250 µm Mylar and 150 µm polyethylene) for the Threshold Cherenkov counters (XCET) has been modelled and verified for its implementation. The XCET is a detector used to count the number of selected charged particles in the beam by adjusting the pressure that leads to the emission of Cherenkov photons only above certain pressure threshold. Simultaneously, the charged particles pass from a vacuum environment to the pressurized refractive gas vessel through a solid interface. Minimal material in this solid interface is therefore crucial to avoid interactions of the low-energy particles which may lead to beam intensity loss or background production. Hence, thin and low-density materials are required to mitigate multiple scattering and energy loss of the incoming particles while still allowing the needed pressures inside the counter vessel. A XCET validation methodology was conducted using Finite Element Analysis (FEA), followed by experimental validations performing burst pressure tests and using Digital Image Correlation (DIC).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB410

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 24 August 2021

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WEXC04

Simulations of Beam Strikes on Advanced Photon Source Upgrade Collimators using FLASH, MARS, and elegant

simulation, electron, storage-ring, radiation

2562

J.C. Dooling, M. Borland, A.M. Grannan, C.J. Graziani, R.R. Lindberg, G. Navrotski
ANL, Lemont, Illinois, USA
N.M. Cook
RadiaSoft LLC, Boulder, Colorado, USA
D.W. Lee, Y. Lee
UCSC, Santa Cruz, California, USA

Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357.
Modeling of high-energy-density electron beams on collimators proposed for the Advanced Photon Source Upgrade (APS-U) storage ring (SR) is carried out with codes FLASH, MARS, and elegant. Code results are compared with experimental data from two separate beam dump studies conducted in the present APS SR. Whole beam dumps of the 6-GeV, 200 mA, ultra-low emittance beam will deposit acute doses of 30 MGy within 10 to 20 microseconds, leading to hydrodynamic behavior in the collimator material. Goals for coupling the codes include accurate modeling of the hydrodynamic behavior, methods to mitigate damage, and understanding the effects of the resulting shower downstream of the collimator. Relevant experiments, though valuable, are difficult and expensive to conduct. The coupled codes will provide a method to model differing geometries, materials, and loss scenarios. Efforts thus far have been directed toward using FLASH to reproduce observed damage seen in aluminum test pieces subjected to varying beam strike currents. Stabilizing the Eulerian mesh against large energy density gradients as well as establishing release criteria from solid to fluid forms are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXC04

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paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 30 August 2021

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WEXC05

First Results Operating a Long-Period EPU in Universal Mode at the Canadian Light Source

polarization, focusing, undulator, injection

2566

W.A. Wurtz, C.K. Baribeau, D. Bertwistle, M.J. Sigrist
CLS, Saskatoon, Saskatchewan, Canada

The Quantum Materials Spectroscopy Centre beamline at the Canadian Light Source (CLS) requires photons with energies as low as 15 eV with circular polarization at the end station. This energy range is accomplished on the 2.9 GeV CLS storage ring using an elliptically polarizing undulator (EPU) with a 180 mm period, which we call EPU180. In order to realize circular polarized photons at the end station with this low energy, we must overcome two technical issues. First, the beamline optics distort the polarization of the light, so we compensate by providing light with a flattened, tilted polarization ellipse at the source point - a mode of operation known as universal mode. Second, the device has a strong effect on the electron beam due to dynamic focusing and is capable of reducing the injection efficiency to zero. We overcome this non-linear dynamic focusing using current strips adhered to the vacuum chamber. In this report, we present the first results with operating EPU180 in universal mode and we recover the dynamic aperture using the current strips.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXC05

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paper received ※ 13 May 2021 paper accepted ※ 05 July 2021 issue date ※ 11 August 2021

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WEPAB021

Development and Testing of a Cherenkov Beam Loss Monitor in CLEAR Facility

experiment, detector, electron, beam-losses

2640

S. Benitez Berrocal, E. Effinger, W. Farabolini, A. Gilardi, P. Korysko, E. Lima, B. Salvachua, W. Viganò
CERN, Geneva 23, Switzerland
P. Lane
University of Huddersfield, Huddersfield, United Kingdom

Beam Loss Monitors are fundamental diagnostic systems in particle accelerators. Beam losses are measured by a wide range of detectors with excellent results; most of these devices are used to measure local beam losses. However, in some accelerators there is the need to measure beam losses continuously localized over longer distances i.e., several tens of meters. For this reason, a beam loss detector based on long optical fibres is now under study. As part of the design, several simulations, comparing different possible detection scenarios, have been performed in FLUKA and bench-marked with experimental data. An experimental campaign was performed with an electron beam in the CERN Linear Electron Accelerator for Research (CLEAR) in November 2020. The light emitted from the optical fibre was captured using Silicon Photo-Multipliers (SiPM) coupled at each fibre’s end. In this poster, the first results of a beam loss detector based on the capture of Cherenkov photons generated by charged particles inside multimode silica fibres are presented.

Poster WEPAB021 [0.724 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB021

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paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 31 August 2021

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WEPAB029

Challenges for the Interaction Region Design of the Future Circular Collider FCC-ee

detector, simulation, background, collider

2668

M. Boscolo, A. Ciarma, F. Fransesini, L. Pellegrino
INFN/LNF, Frascati, Italy
N. Bacchetta
INFN- Sez. di Padova, Padova, Italy
M. Benedikt, H. Burkhardt, M.A. Jones, R. Kersevan, M. Lueckhof, E. Montbarbon, K. Oide, L. Watrelot, F. Zimmermann
CERN, Meyrin, Switzerland
L. Brunetti, M. Serluca
IN2P3-LAPP, Annecy-le-Vieux, France
M. Dam
NBI, København, Denmark
M. Koratzinos
MIT, Cambridge, Massachusetts, USA
M. Migliorati
INFN-Roma1, Rome, Italy
A. Novokhatski, M.K. Sullivan
SLAC, Menlo Park, California, USA
F. Poirier
CNRS - DR17, RENNES, France

Funding: This work was partially supported by the EC HORIZON 2020 project FCC-IS, grant agreement n.951754, and by the U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-76SF-00515.
The FCC-ee is a proposed future high-energy, high-intensity and high precision lepton collider. Here, we present the latest developments for the FCC-ee interaction regions, which shall ensure optimum conditions for the particle physics experiments. We discuss measures of background reduction and a revised interaction region layout including a low impedance compact beam chamber design. We also discuss the possible impact of the radiation generated in the interaction region including beamstrahlung.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB029

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paper received ※ 11 May 2021 paper accepted ※ 23 June 2021 issue date ※ 30 August 2021

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WEPAB062

Investigation of the Thomson Scattering Influence on Electron Beam Parameters in an Energy-Recovering Linear Accelerator on the Example of MESA

electron, scattering, HOM, laser

2732

C.L. Lorey, K. Aulenbacher, A. Meseck
KPH, Mainz, Germany

Funding: funded by DFG through GRK2128 ACCELENCE
At the Johannes Gutenberg University (JGU) in Mainz, the Mainz Energy-recovering Superconducting Accelerator (MESA) is currently under construction. It is designed to deliver electron beams of up to 155 MeV. As it can be operated in an energy-recovery (ER) mode thus allowing for high repetition rate, it is a promising candidate for a high flux Thomson scattering based gamma source. This paper will provide a status update on the study of the impact of Thomson scattering on electron beam parameters and the underlying mechanics. Further, the implementation into a simulation code will be discussed.

Poster WEPAB062 [1.307 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB062

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 02 September 2021

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WEPAB067

High Duty Cycle EUV Radiation Source Based on Inverse Compton Scattering

laser, electron, gun, emittance

2748

R. Huang, Q.K. Jia, C. Li
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by the National Natural Science Foundation of China Grant Number 11805200, and National Key Research and Development Program of China No. 2016YFA0401901.
ICS can obtain quasi-monochromatic and directional EUV radiation via a MeV-scale energy electron beam and a micron-scale wavelength laser beam, which enables a dramatic reduction in dimension and expense of the system, and makes it an attractive technology in research, industry, medicine and homeland security. Here we describe an EUV source based on high repetition ICS system. The scheme exploits the output from the laser-electron interaction between a MW-ps laser at MHz repetition-rate and a high quality electron beam with an energy of a few MeV at MHz repetition-rate.

Poster WEPAB067 [1.551 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB067

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paper received ※ 23 May 2021 paper accepted ※ 24 June 2021 issue date ※ 02 September 2021

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WEPAB075

Xenos: X-Ray Monte Carlo Code Suite

electron, simulation, positron, operation

2766

S. Humphries
Field Precision, Albuquerque, New Mexico, USA

Xenos is an integrated 3D code suite for the design of X-ray sources and electron beam devices. The component programs run under all versions of Windows. This paper describes unique features of Xenos compared to other Monte Carlo packages: 1) representation of geometry and deposited dose on a finite-element mesh supported by an interactive mesh generator, 2) inclusion of full 3D electric and magnetic fields in Monte Carlo simulations, 3) an integrated user environment for input and output calculations (e.g., electron gun design, target heating, …) and 4) extended parallel-computing support for high-accuracy solutions. Xenos employs the full capabilities of multi-core computers and allows parallel computations on an unlimited number of independent computers.
* Sempau J., et.al. (2003), "Experimental benchmarks of the Monte Carlo code PENELOPE", Nucl. Instrum. Meth. B 207, 107-123.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB075

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paper received ※ 10 May 2021 paper accepted ※ 23 June 2021 issue date ※ 25 August 2021

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WEPAB080

Near Threshold Pion Photoproduction on Deuterons

experiment, multipole, polarization, scattering

2775

V. Shastri, V. Aswathi, S.P. Shilpashree
Christ University, School of Engineering and Technology, Bangalore, India

The study of photoproduction of mesons is a prime tool in understanding the properties of strong interactions. The only photoproduction reaction on deuteron with two-body final state is coherent pion photoproduction reaction. Several theoretical studies are being carried out on the pion photoproduction on deuterons since several decades. On the experimental side, the accelerator and detector technology has improved the developments. In the recent years, measurements of tensor analyzing powers associated with coherent and incoherent pion photoproduction are also being carried out at the VEPP-3 electron storage ring. In one of the recent measurements, Rachek et al"*" have observed discrepancy between theory and experiment at higher photon energies and have suggested for improvement of the theoretical models. In a more recent analysis,"**" the role of D-wave component on spin asymmetries have been identified. In view of these developments, the purpose of the present contribution is to study coherent pion photoproduction on deuterons using model independent irreducible tensor formalism developed earlier to study the photodisintegration of deuterons."***"
*I A Rachek et al., Few-Body Syst., 58, 29 (2017)
**H M Al Ghamdi et al, Brazillian Journal of Physics, 50, 615 (2020)
*** G Ramachandran, S P Shilpashree Phys. Rev. C 74, 052801(R) (2006)

Poster WEPAB080 [0.203 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB080

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paper received ※ 29 May 2021 paper accepted ※ 01 July 2021 issue date ※ 16 August 2021

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WEPAB087

Observation of Undulator Radiation Generated by a Single Electron Circulating in a Storage Ring and Possible Applications

synchrotron, electron, radiation, undulator

2790

I. Lobach
University of Chicago, Chicago, Illinois, USA
A. Halavanau, Z. Huang
SLAC, Menlo Park, California, USA
K. Kim
ANL, Lemont, Illinois, USA
S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA

An experimental study into the undulator radiation, generated by a single electron was carried out at the Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab. The individual photons were detected by a Single Photon Avalanche Diode (SPAD) at an average rate of 1 detection per 300 revolutions in the ring. The detection events were continuously recorded by a picosecond event timer for as long as 1 minute at a time. The collected data were used to test if there is any deviation from the classically predicted Poissonian photostatistics. It was motivated by the observation * of sub-Poissonian statistics in a similar experiment. The observation * could be an instrumentation effect related to low detection efficiency and long detector dead time. In our experiment, the detector (SPAD) has a much higher efficiency (65%) and a much lower dead time. In addition, we show that the collected data (recorded detection times) can be used to study the synchrotron motion of a single electron and infer some parameters of the ring. For example, by comparing the results of simulation and measurement for the synchrotron motion we were able to estimate the magnitude of the RF phase jitter.
* Teng Chen and John M. J. Madey, Phys. Rev. Lett. 86, 5906, June 2001

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB087

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paper received ※ 17 May 2021 paper accepted ※ 24 June 2021 issue date ※ 16 August 2021

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WEPAB099

Near-Threshold Nonlinear Photoemission From Cu(100)

electron, laser, cathode, experiment

2822

C.J. Knill, S.S. Karkare
Arizona State University, Tempe, USA
H.A. Padmore
LBNL, Berkeley, California, USA

Funding: National Science Foundation Grant No. PHY-1549132
Photocathodes that have a low mean transverse energy (MTE) are crucial to the development of compact X-ray Free Electron Lasers (XFEL) and ultrafast electron diffraction (UED) experiments. For FELs, low MTE cathodes result in a lower requirement for electron energy when lasing at a defined energy, and for a defined electron energy result in lasing at higher energy. For UED experiments, low MTE cathodes give a longer coherence length, allowing measurements on larger unit cell materials. A record low MTE of 5 meV has been recently demonstrated from a Cu (100) surface when measured near the photoemission threshold and cooled down to 30 K with liquid Helium [*]. For UED and XFEL applications that require a high charge density, the low quantum efficiency of Cu (100) near threshold necessitates the use of a high laser fluence to achieve the desired charge density [**]. At high laser fluences the MTE is limited by nonlinear effects, and therefore it is necessary to investigate near photoemission threshold at these high laser fluences. In this paper we report on nonlinear, near-threshold photoemission from a Cu (100) cathode, and its effect on the MTE.
* S. Karkare et al, Phys. Rev. Lett. 125, 054801 (2020)
** J. Bae et al, J. Appl. Phys., 124, 244903 (2018)

Poster WEPAB099 [0.829 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB099

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paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 29 August 2021

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WEPAB112

Performance Characterisation of a Cu (100) Single-Crystal Photocathode

cathode, electron, emittance, experiment

2860

L.A.J. Soomary, D.P. Juarez-Lopez, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The search for high performance photocathode electron sources is a priority in the accelerator science community. The surface characteristics of a photocathode define important factors of the photoemission including the intrinsic emittance, the quantum efficiency and the work function of the photocathode. These factors in turn define the electron beam performance which are measurable as emittance, brightness and energy spread. We have used ASTeC’s Multiprobe (SAPI)* to characterise and analyse photocathode performance using multiple techniques including XPS, STM, and LEED imaging, and their Transverse Energy Spread Spectrometer (TESS)** to measure mean transverse energy (MTE). We present characterisation measurements for a Cu (100) single-crystal photocathode sample with data from SAPI confirming the crystallographic face and showing surface composition and roughness, supported by data from TESS showing the photocathode electron beam energy spread.
* B.L. Militsyn, 4-th EuCARD2 WP12.5 meeting, Warsaw, 14-15 March 2017
**Proc. FEL’13, TUPPS033, 290-293

Poster WEPAB112 [0.814 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB112

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 22 August 2021

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WEPAB127

Accurate Measurements of Undulator Particle Beam Entrance/Exit Angles Using Improved Hall Probes and Calibration Process

undulator, insertion, insertion-device, closed-orbit

2907

I. Vasserman, R.J. Dejus, Y. Piao, M.F. Qian, J.Z. Xu
ANL, Lemont, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
The Advanced Photon Source Upgrade (APS-U) undulator requirements were changed from the first and second field integrals to the entrance and exit angles of the particle beam. This provides the user with the best radiation view angle by the storage ring closed orbit correction system. To satisfy such requirements we use improved Senis Hall probes and calibration process. In addition to the normal NMR calibration of the sensors, the calibration was further refined using stretch-coil integrals to make accurate measurements.

Poster WEPAB127 [0.620 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB127

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paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 19 August 2021

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WEPAB128

Recent Experience with Magnet Sorting for APS-U Hybrid Undulators

undulator, quadrupole, permanent-magnet, synchrotron

2910

I. Vasserman, R.J. Dejus, Y. Piao, M.F. Qian, J.Z. Xu
ANL, Lemont, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
The quality of permanent magnets plays a particularly important role in undulator performance. Many different types of magnet sorting to enhance undulator performance have been carried out at different facilities. Meanwhile, progress in improving magnet quality has been made by different vendors. At the Advanced Photon Source (APS) we have assembled, measured, and analyzed over 14 new undulators of the same mechanical design, some of them with sorted magnets and some unsorted. The performance differences appear to be insignificant in meeting the tight APS Upgrade (APS-U) undulator requirements.

Poster WEPAB128 [0.395 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB128

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paper received ※ 16 May 2021 paper accepted ※ 09 June 2021 issue date ※ 10 August 2021

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WEPAB132

Towards a Superconducting Undulator Afterburner for the European XFEL

FEL, undulator, electron, vacuum

2921

S. Casalbuoni, J.E. Baader, G. Geloni, V. Grattoni, D. La Civita, C. Lechner, B. Marchetti, S. Serkez, H. Sinn
EuXFEL, Schenefeld, Germany
W. Decking, L. Lilje, S. Liu, T. Wohlenberg, I. Zagorodnov
DESY, Hamburg, Germany

We propose to develop, characterize and operate a superconducting undulator (SCU) afterburner consisting of 5 undulator modules (1 module = 2 times SCU coil of 2 m length and 1 phase shifter) at the SASE2 hard X-ray beamline of European XFEL. This afterburner has the potential to produce an output of more than 10¹⁰ ph/pulse at photon energies above 30 keV. The project is divided into the production of a pre-series prototype module and a small-series production of 5 modules. Central goals of this R&D activity are: the demonstration of the functionality of SCUs at an X-ray FEL, the set up of the needed infrastructure to characterize and operate SCUs, the industrialization of such undulators, and the reduction of the price per module. In this contribution, the main parameters and specifications of the pre-series prototype module (S-PRESSO) are described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB132

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paper received ※ 15 May 2021 paper accepted ※ 05 July 2021 issue date ※ 14 August 2021

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WEPAB209

Review of Medical Accelerator Development at Sameer, India

linac, electron, cavity, acceleration

3113

T.S. Dixit, N. Bansode, A.P. Bhagwat, S.T. Chavan, A.P. Deshpande, G. Gaikwad, S. Ghosh, R. Krishnan, C.S. Nainwad, G.D. Panchal, S.N. Pethe, K.A. Thakur, V.B. Ukey, M.M. Vidwans
SAMEER, Mumbai, India

Funding: Ministry of Electronics and Information Technology (MeitY), Government of India
At the Medical Electronics Division of SAMEER, R&D for the development of a 4 MeV energy electron linac for Cancer therapy was taken up in the late ’80s. An S-band standing wave side coupled structure operating at pi/2 mode was developed for electron acceleration. The linac was integrated with other subsystems in collaboration with CSIO and PGIMER and the first machine was commissioned at PGI, Chandigarh in 1990. Thereafter, a lot of modifications like energy, dose rate, iso-center height etc. were made in the system, and later 4 more machines were commissioned in hospitals for treatment. More than 1,50,000 patients have been treated using SAMEER’s 6 MeV oncology system. Subsequently, development of dual-mode and variable energy electron and photon output machines was undertaken. Two-photon energies of 6 and 15 MV and multiple electron energies starting from 6 to 18 MeV for treatment was offered from the linac. The electron energy variation was done using plunger mechanism in the side coupling cavity. This linac was successfully baked and RF tested for various parameters. This paper describes the experimental parameters achieved for both low and high energy dual-mode linac.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB209

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paper received ※ 14 May 2021 paper accepted ※ 07 July 2021 issue date ※ 13 August 2021

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WEPAB255

Simulation Studies on the Interactions of Electron Beam with Wastewater

electron, radiation, simulation, target

3236

X. Li, H. Baumgart, G. Ciovati
ODU, Norfolk, Virginia, USA
G. Ciovati, F.E. Hannon, S. Wang
JLab, Newport News, Virginia, USA

Funding: Jefferson Lab LDRD
The manufactured chemical pollutants, like 1,4 dioxane and PFAS (per- and polyfluroralkyl substances), found in the underground water and/or drinking water are challenging to be removed or biodegraded. Energetic electrons are capable of mediating and removing them. This paper utilizes FLUKA code to evaluate the beam-wastewater interaction effects with different energy, space and divergence distributions of the electron beam. With 8 MeV average energy, the electron beam exits from a 0.0127 cm thick titanium window, travels through a 4.3 cm distance air and a second 0.0127 cm thick stainless water container window with 2.43 cm radius, and finally is injected into the water area, where the volume of water is around 75 cubic cm. The distribution parameters of the electron beam are from the GPT (General Particle Tracer) simulations for UITF (Upgraded Injector Test Facility) in Jefferson lab. By varying the distributions, several measurements including the dose (or energy deposition) distribution, electron fluence, photon fluence are scored and compared. Taking the comparisons into consideration, this paper is aiming to find better electron beams for the wastewater irradiation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB255

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paper received ※ 20 May 2021 paper accepted ※ 25 June 2021 issue date ※ 14 August 2021

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WEPAB340

Pressure Simulations for the EIC Interaction Region

vacuum, electron, detector, simulation

3483

M.L. Stutzman
JLab, Newport News, Virginia, USA

Background detector rates in the Electron Ion Collider depend in part on the pressure in the interaction region. Materials choice, synchrotron radiation induced desorption, conditioning time and pumping configuration all affect the pressure in the system. Simulations of the region using Synrad and Molflow+ coupled simulation codes will be presented for various configruations and conditioning times.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB340

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paper received ※ 18 May 2021 paper accepted ※ 20 July 2021 issue date ※ 11 August 2021

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WEPAB402

Status and Progress of the High-Power RF System for High Energy Photon Source

cavity, booster, GUI, storage-ring

3653

T.M. Huang, J. Li, H.Y. Lin, Y.L. Luo, Q. Ma, W.M. Pan, P. Zhang, F.C. Zhao
IHEP, Beijing, People’s Republic of China

Funding: Work was supported in part by High Energy Photon Source, a major national science and technology infrastructure in China, and in part by the National Natural Science Foundation of China(12075263).
High Energy Photon Source is a 6-GeV diffraction-limited synchrotron light source currently under construction in Beijing. Three types of high-power RF systems are used to drive the booster and the storage ring. For the booster ring, a total of 600-kW continuous-wave (CW) RF power is generated by six 500-MHz solid-state power amplifiers (SSA) and fed into six normal-conducting copper cavities. Concerning the storage ring, five CW 260-kW SSAs at 166 MHz and two CW 260-kW SSAs at 500-MHz are used to drive five fundamental and two third-harmonic superconducting cavities respectively. The RF power distributions are realized by 9-3/16" rigid coaxial line for the 166-MHz system and EIA standard WR1800 waveguide for the 500-MHz one. High-power circulators and loads are installed at the outputs of all SSAs to further protect the power transmitters from damages due to reflected power although each amplifier module is equipped with individual isolators. The overall system layout and the progress of the main components are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB402

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paper received ※ 18 May 2021 paper accepted ※ 02 July 2021 issue date ※ 14 August 2021

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WEPAB405

Supercontinuum Generation for the Improvement of Pulse Radiolysis System

laser, radiation, polarization, electron

3657

M. Sato, Y. Kaneko, Y. Koshiba, M. Washio
RISE, Tokyo, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

Pulse radiolysis is one of the absorption measurement methods for investigating the fundamental, ultrafast process of radiation chemical reactions. Analytical light is transmitted simultaneously with the timing of electron beam irradiation, and its absorption by reactive species is detected. Since the target reactions arise in pico second time scale or even shorter, analytical light is required to have such duration. Besides, so as not to be buried in noise of the radiation source, the optical power of the analytical light must be high enough. Furthermore, it is desirable that the analytical light covers visible region because important absorptions caused by irradiation products such as hydrated electron, hydroxyl radical, or so exist in the region. We considered that the supercontinuum light generated from an ultrashort pulse laser is suitable as an analytical light because it has all these characteristics. In this study, we generate the second harmonic (775 nm) of an erbium fiber laser (1550 nm) as a seed laser for supercontinuum generation. In this presentation, we report the current situation of our laser system and prospects.

Poster WEPAB405 [0.734 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB405

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paper received ※ 18 May 2021 paper accepted ※ 01 September 2021 issue date ※ 20 August 2021

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THPAB009

A Hard X-Ray Compton Source at CBETA

electron, laser, scattering, brilliance

3765

K.E. Deitrick, C. Franck, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J. Crone, H.L. Owen
UMAN, Manchester, United Kingdom
G.A. Krafft
JLab, Newport News, Virginia, USA
G.A. Krafft, B. Terzić
ODU, Norfolk, Virginia, USA
B.D. Muratori, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
B.D. Muratori, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Inverse Compton scattering (ICS) holds the potential for future high flux, narrow bandwidth x-ray sources driven by high quality, high repetition rate electron beams. CBETA, the Cornell-BNL Energy recovery linac (ERL) Test Accelerator, is the world’s first superconducting radiofrequency multi-turn ERL, with a maximum energy of 150 MeV, capable of ICS production of x-rays above 400 keV. We present an update on the bypass design and anticipated parameters of a compact ICS source at CBETA. X-ray parameters from the CBETA ICS are compared to those of leading synchrotron radiation facilities, demonstrating that, above a few hundred keV, photon beams produced by ICS outperform those produced by undulators in term of flux and brilliance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB009

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paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 10 August 2021

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THPAB035

Study of the Tolerances for Superconducting Undulators at the European XFEL

undulator, FEL, electron, simulation

3819

B. Marchetti, S. Casalbuoni, V. Grattoni, S. Serkez
EuXFEL, Schenefeld, Germany

European XFEL is investing in the development of superconducting undulators (SCUs) for future upgrade of its beamlines SCUs made of NbTi, working at 2K, with a period length of 15 mm and a vacuum gap of 5 mm allow covering a range between 54 keV and 100 keV for 17.5 GeV electron energy. The effect of mechanical errors in the distribution of K along the undulators is more relevant for working points at lower photon energy, which are obtained using a higher magnetic field in the undulator. In this article we investigate the effect of error distribution in the K-parameter for a working point at 50keV photon energy obtained injecting an electron beam with 16.5 GeV energy from the XFEL linear accelerator in a undulator line composed by SCUs with 1.58 T peak magnetic field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB035

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paper received ※ 12 May 2021 paper accepted ※ 05 July 2021 issue date ※ 18 August 2021

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THPAB036

Superconducting Phase Shifter Design for the Afterburner at the European XFEL

electron, FEL, undulator, operation

3823

V. Grattoni, J.E. Baader, S. Casalbuoni
EuXFEL, Schenefeld, Germany

At the European XFEL, a superconducting afterburner is under design for the SASE2 hard X-ray beamline. It will consist of 5 undulator modules. One module corresponds to two superconducting undulator (SCU) coils of 2 m length plus one phase shifter. Such an afterburner will enable photon energies above 30 keV. Superconducting (SC) phase shifters will be installed in each undulator module to keep the correct phase delay between the electron beam and photon beam. In this contribution, we present the required SC phase shifter parameters to enable operation in the electron beam energy range 11.5-17.5 GeV. We also analyze different magnetic designs satisfying the calculated specifications.

Poster THPAB036 [0.991 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB036

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paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 12 August 2021

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THPAB040

A Phase Shifter for Inline Undulators at the Advanced Photon Source Upgrade Project

undulator, electron, permanent-magnet, radiation

3830

E.R. Moog, R.J. Dejus, A.T. Donnelly, Y. Piao, M.F. Qian, I. Vasserman, J.Z. Xu
ANL, Lemont, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE AC02-06CH11357.
Several undulator lines for the Advanced Photon Source Upgrade (APS-U) will consist of two inline undulators. In order to keep the undulators operating with optimal phasing over the full range of gaps, a phase shifter will be included between the undulators. A design has been developed for a phase shifter that will serve for a variety of undulator period lengths and gap ranges. The permanent-magnet phase shifter will use SmCo magnets to reduce the risk of radiation-induced demagnetization. The available space between the undulators is tight, so magnetic shields are placed between the undulators, the phase shifter, and the corrector magnet that is also located in the inter-undulator space. While these shields guard against magnetic cross-talk between the devices as the undulator and phase shifter gaps change, they do have an effect on the end fields of the devices. These end-field effects are examined and relevant tolerances are set and presented.

Poster THPAB040 [0.429 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB040

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paper received ※ 23 May 2021 paper accepted ※ 21 June 2021 issue date ※ 14 August 2021

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THPAB041

Design of Photon Masks for the ILC Positron Source

undulator, positron, site, target

3834

K.S. Alharbi, G.A. Moortgat-Pick, A. Ushakov
University of Hamburg, Hamburg, Germany
K.S. Alharbi, S. Riemann
DESY Zeuthen, Zeuthen, Germany
K.S. Alharbi, A.O. Alrashdi
King Abdulaziz City for Science and Technology (KACST), The National Center for Accelerator Technology, Riyadh, Kingdom of Saudi Arabia
G.A. Moortgat-Pick
DESY, Hamburg, Germany
P. Sievers
CERN, Geneva, Switzerland

A long superconducting helical undulator is planned as baseline to produce polarized positrons at the International Linear Collider (ILC). To protect the undulator walls from synchrotron radiation, masks must be inserted along the undulator line. The power distribution deposited at these masks is studied in order to design the photon masks.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB041

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paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 12 August 2021

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THPAB045

Design of a Short Period Helical Superconducting Undulator

undulator, FEL, electron, simulation

3844

A.G. Hinton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
J. Boehm, L. Cooper, B. Green, T. Hayler, P. Jeffery, C.P. Macwaters
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
S. Milward
DLS, Oxfordshire, United Kingdom
B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
B.J.A. Shepherd
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Superconducting technology provides the possibility to develop short period, small bore undulators that can generate much larger magnetic fields than alternative technologies. This may allow an XFEL with optimised superconducting undulators to cover a broader range of wavelengths than traditional undulators. At STFC, we have undertaken work to design and build a prototype helical superconducting undulator (HSCU) module with parameters suitable for use on a future XFEL facility. This work includes the design of a full 2 m long undulator module, including an undulator with 13 mm period and 5 mm inner winding diameter, the supporting cryogenic and vacuum systems required for operation, and quadrupoles, phase shifters and correction magnets for use between undulator sections. We present here the magnetic and mechanical design of the HSCU. The choice of undulator parameters and their influence on the design is discussed. A turnaround scheme to allow continuous winding of the undulator without the need for superconducting joints is also presented. Techniques for winding the undulator are currently being investigated and a short prototype will soon be wound and tested.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB045

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paper received ※ 17 May 2021 paper accepted ※ 18 June 2021 issue date ※ 21 August 2021

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THPAB050

Compact Hybrid Planar Permanent Magnet Undulator Design for the APS Upgrade

undulator, ECR, lattice, permanent-magnet

3859

M. Abliz, M. Borland, J.H. Grimmer, J.S. Kerby, M. Ramanathan, A. Xiao
ANL, Lemont, Illinois, USA

We report on the successful design of a compact 28-mm period hybrid planar permanent magnet (HPPM) undulator for the Advanced Photon Source Upgrade (APS-U) project. The design produces a peak field of 9750 G at a gap of 8.5 mm, with a pole width reduced to 35 mm as compared to the planar undulators currently in use at the Advanced Photon Source. The design includes a detailed investigation into the origin of the HPPM undulator demagnetization. We report on a finding of an optimization method that reduces the demagnetization field and increases the field at the gap center of the design. It includes an optimization of the pole edges to increase the field and decrease roll-off in the transverse direction. Further design optimizations include analyses of the mechanical assembly tolerances and comparison with the original design before building the device. Beam physics analyses included kick-map analysis, dynamic acceptance (DA), local momentum acceptance (LMA), and Touschek lifetime of this design were performed with the 42-pm lattice of the APS-U. Detailed magnetic design, effective field, field roll-off, magnetic force, and tracking results are reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB050

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paper received ※ 14 May 2021 paper accepted ※ 01 September 2021 issue date ※ 21 August 2021

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THPAB051

Vertical Septum Magnet Design for the APS Upgrade

septum, simulation, electron, magnet-design

3862

M. Abliz, M. Borland, H. Cease, G. Decker, A.K. Jain, M.S. Jaski, M. Kasa, J.S. Kerby, U. Wienands, A. Xiao
ANL, Lemont, Illinois, USA
J.W. Amann
SLAC, Menlo Park, California, USA
D.J. Harding
Fermilab, Batavia, Illinois, USA

The vertical injection scheme proposed for the APS Upgrade (APS-U) Project requires a challenging septum magnet that must meet stringent beam physics, magnetic field leakage, and vacuum requirements. The current iteration of this magnet design includes an enlarged stored-beam chamber aperture of 9 mm x 12 mm and a reduction of the septum thickness to 1.5 mm. The enlarged aperture accommodates a non-evaporable getter (NEG)-coated stored beam chamber to better achieve the required vacuum. A prototype septum magnet has been built and measurements confirm the cancellation of a peak leakage field even though the value is six times larger than the design. The leakage field measured at the upstream (US) end cancels the downstream (DS) end as was expected by design. The measured and simulated leakage field and the stored beam trajectories are reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB051

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paper received ※ 14 May 2021 paper accepted ※ 01 September 2021 issue date ※ 27 August 2021

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THPAB052

Insertion Devices at the MAX IV 3 GeV Ring

wiggler, undulator, MMI, vacuum

3865

H. Tarawneh, M. Ebbeni, M. Gehlot, M. Holz
MAX IV Laboratory, Lund University, Lund, Sweden

Currently, there are 8 Insertion Devices (ID) installed and in operation and 2 new ones to be installed end of 2021 at the MAX IV 3 GeV storage ring. In this paper, the first commissioning results of the three newly installed IDs in 2020 will be described. The new IDs are one APPLE II for SoftiMAX beamline and two In-vacuum Undulators (IVU) for the DanMAX and CoSAXS beamlines. The mitigation scheme adopted to reduce undulator-like radiation from BALDER in-vacuum wiggler will be discussed. Two new IVUs with a period length of 17 mm and 18 mm for the ForMAX and MicroMAX beamlines will be installed during the winter shutdown of 2021-2022. Both IDs have 3 m lengths and a minimum gap of 4 mm. In this paper, the magnetic measurement results will be presented in terms of the achieved field quality and phase error.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB052

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paper received ※ 11 May 2021 paper accepted ※ 02 July 2021 issue date ※ 02 September 2021

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THPAB053

Magnetic Field Calculation of Planar SCUs Using ANSYS Maxwell

undulator, FEL, software, software-tool

3868

Y. Shiroyanagi, E.A. Anliker, Q.B. Hasse, H. Hu, Y. Ivanyushenkov, M. Kasa, I. Kesgin
ANL, Lemont, Illinois, USA

Funding: This work was supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) Upgrade includes a 4.8-m-long superconducting undulator (SCU) cryostat containing two 1.9-m-long, 16.5-mm-period planar NbTi undulator magnets. The magnetic and mechanical design of this magnet follows the design of the existing 1.1-m-long, 18-mm-period planar SCU that is currently in operation at the APS *. Although OPERA is a reliable standard software tool for magnetic field calculations, ANSYS Maxwell 3D has the advantage of calculating a large and complex geometry. In this paper, first, the magnetic field map, including the peak field and end fields, is bench-marked against the magnetic measurement data of the existing planar SCU18-1. Then, corrector current optimization is presented for the 1.5-m-long, 21-mm-period planar SCU. Finally, a magnetic field model of a full-scale, 1.9-m-long planar SCU is presented.
* Y. Ivanyushenkov et al., Phys. Rev. Accel. Beams 20, 100701 (2017).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB053

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paper received ※ 18 May 2021 paper accepted ※ 18 June 2021 issue date ※ 11 August 2021

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THPAB054

Measurement Results of the First Scape Prototype

undulator, insertion, superconducting-magnet, insertion-device

3872

M. Kasa, E.A. Anliker, Q.B. Hasse, Y. Ivanyushenkov, I. Kesgin, Y. Shiroyanagi, E. Trakhtenberg
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The SCAPE (SuperConducting Arbitrarily Polarizing Emitter) undulator is under development at the Advanced Photon Source (APS) as a part of the APS upgrade. SCAPE is comprised of four superconducting magnets which are arranged to create an on-axis undulator field that can be planar, elliptical, or circular. As a first step towards developing a full length device, a 0.5-meter long prototype was manufactured and assembled for testing in a liquid helium bath cryostat. A description of the mechanical assembly and subsequent measurement results of the first prototype will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB054

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paper received ※ 19 May 2021 paper accepted ※ 01 September 2021 issue date ※ 22 August 2021

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THPAB061

Pulse-Burst CO₂ Laser for High-Brilliance Compton Light Sources

laser, electron, synchrotron, brightness

3890

I. Pogorelsky, M.N. Polyanskiy, T.V. Shaftan
BNL, Upton, New York, USA

Funding: U.S. Department of Energy under contract DE-SC0012704
We propose a novel architecture for a mid-IR, high-repetition, kilowatt-class, CO₂ laser system operating in a pulse-burst regime and its implementation in In-verse Compton Scattering (ICS) sources of x-ray and gamma-ray radiation. Different types of particle accelerators are considered for conversion to such ICS sources, including energy recovery linacs and synchrotron storage rings. The expected ICS performance parameters are compared with earlier proposals where CBETA and DAΦNE accelerators have been paired with near-IR, mode-locked solid-state lasers operating at a multi-megahertz repetition rate. A considerable increase in acting laser energy attainable in our CO₂ laser-based scheme, combined with an order of magnitude higher number of laser photons per Joule of energy allows maintaining a similarly high average flux of produced hard x-rays while the peak flux and brilliance will be raised by three to four orders of magnitude compared to aforementioned schemes based on near-IR lasers.

Poster THPAB061 [1.082 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB061

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paper received ※ 12 May 2021 paper accepted ※ 21 June 2021 issue date ※ 29 August 2021

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THPAB065

Experimental Verification of the Source of Excessive Helical SCU Heat Load at APS

vacuum, radiation, synchrotron-radiation, synchrotron

3904

V. Sajaev, J.C. Dooling, K.C. Harkay
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Immediately after the installation of the Helical superconducting undulator (HSCU) in the APS storage ring, higher than expected heating was observed in the cryogenic cooling system. Steering the electron beam orbit in the upstream dipole reduced the amount of synchrotron radiation reaching into the HSCU and allowed the device to properly cool and operate. The simplest explanation of the excessive heat load was higher than expected heat transfer from the vacuum chamber to the magnet coils. However, modeling of the synchrotron radiation interaction with the HSCU vacuum chamber showed that Compton scattering could also result in synchrotron radiation penetrating the vacuum chamber and depositing energy directly into the HSCU coils**. In this paper, we present experimental evidence that the excessive heat load of the HSCU coils is not caused by the heat transfer from the vacuum chamber but resulted from the synchrotron radiation penetrating the vacuum chamber.
* M. Kasa et. al., Phys. Rev. AB, v. 23 050701 (2020)
** J. Dooling et. al., IPAC 2019 Proc., THPTS093 (2019)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB065

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paper received ※ 12 May 2021 paper accepted ※ 02 September 2021 issue date ※ 16 August 2021

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THPAB067

Simulation of the APS-U Orbit Motion Due to RF Noise

simulation, synchrotron, resonance, cavity

3911

V. Sajaev
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
APS Upgrade storage ring will keep the same rf system that is presently used at APS. This rf system has amplitude and phase noise dominated by the lines at 60, 180, and 360 Hz. APS presently operates with synchrotron frequency close to 2 kHz, which is far away from the rf noise frequencies, and still the rf system noise contributes over 2 micrometers rms into the horizontal orbit noise due to beam energy variation. APS-U will operate with a bunch-lengthening cavity, which will lower the synchrotron frequency down to about 200 Hz. This could potentially lead to large orbit noise and other negative consequences due to energy variation caused by the rf system noise. In this paper, we will present simulations of the rf noise-induced orbit motion at APS and APS-U and define the rf amplitude and phase noise requirements that need to be achieved for APS-U operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB067

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paper received ※ 12 May 2021 paper accepted ※ 13 July 2021 issue date ※ 23 August 2021

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THPAB078

SOLEIL Update Status

controls, injection, synchrotron, vacuum

3945

L.S. Nadolski, G. Abeillé, Y.-M. Abiven, F. Bouvet, P. Brunelle, A. Buteau, N. Béchu, I. Chado, M.-E. Couprie, X. Delétoille, A. Gamelin, C. Herbeaux, N. Hubert, J.-F. Lamarre, V. Leroux, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, A. Nadji, R. Nagaoka, S. Pierre-Joseph Zéphir, F. Ribeiro, G. Schagene, K. Tavakoli, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

SOLEIL is both a synchrotron light source and a research laboratory at the cutting edge of experimental techniques dedicated to matter analysis down to the atomic scale, as well as a service platform open to all scientific and industrial communities. This French 2.75 GeV third generation synchrotron light source provides today extremely stable photon beams to 29 beamlines (BLs) complementary to ESRF. We report facility performance, ongoing projects and recent major achievements. Major R&D areas will also be discussed, and progress towards a lattice baseline for making SOLEIL a diffraction limited storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB078

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paper received ※ 22 May 2021 paper accepted ※ 12 July 2021 issue date ※ 22 August 2021

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THPAB085

Status of Insertion Device Tuning for the APS Upgrade

undulator, storage-ring, MMI, permanent-magnet

3966

R.J. Dejus, Y. Piao, M.F. Qian, J.M. TerHAAR, I. Vasserman, J.Z. Xu
ANL, Lemont, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE AC02-06CH11357.
The Advanced Photon Source Upgrade (APS-U) project is developing a multi-bend achromat (MBA) lattice at 6.0-GeV beam energy to replace the existing APS storage ring lattice operating at 7.0 GeV. One of the key components of the project is to design, fabricate, and install optimized insertion devices (IDs) for 35 beamlines. A plan was developed to standardize on four new undulator period lengths for 44 new undulators and to reuse 23 existing undulators with four more different period lengths. Early in the Upgrade project we anticipated there would be large challenges in meeting the tight fabrication and tuning schedules so that all undulators would be ready for installation in the upgraded storage ring prior to beam commissioning. With recent developments and techniques used in the magnetic measurement laboratory, we have successfully tuned many of the new and reused undulators to demanding magnetic field requirements. We will report on the tools and techniques used and on results to date.

Poster THPAB085 [0.890 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB085

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 15 August 2021

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THPAB142

Optical and Surface Characterization of Alkali-Antimonide Photocathodes

cathode, electron, emittance, vacuum

4037

P. Saha, O. Chubenko, G.S. Gevorkyan, A.H. Kachwala, S.S. Karkare, C.J. Knill
Arizona State University, Tempe, USA
E.J. Montgomery, S. Poddar
Euclid Beamlabs, Bolingbrook, USA
H.A. Padmore
LBNL, Berkeley, California, USA

Alkali-antimonides, characterized by high quantum efficiency and low mean transverse energy in visible light, are excellent electron sources to drive x-ray free electron lasers, electron cooling and ultrafast electron diffraction applications etc. Existing studies of alkali-antimonides have focused on quantum efficiency and emittance, but information is lacking on the fundamental aspects of the electronic structure, such as the energy gap of the semiconductor and the density of defects as well as the overall nano-structure of the materials. We are, therefore, conducting photoconductivity measurements to measure fundamental semiconductor properties as well as using atomic force microscope (AFM) and kelvin probe force microscope (KPFM) to measure the nanostructure variations in structure and surface potential.

Poster THPAB142 [1.211 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB142

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paper received ※ 16 May 2021 paper accepted ※ 14 July 2021 issue date ※ 13 August 2021

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THPAB249

X-Ray Beam Position Monitor (XBPM) Calibration at NSRC Solaris

controls, undulator, insertion, radiation

4292

M. Waniczek, A. Curcio, G.W. Kowalski, R. Panaś, A.I. Wawrzyniak
NSRC SOLARIS, Kraków, Poland

During the installation of Front-ends in sections 4th (XMCD beamline frontend) and 6th (PHELIX beamline frontend) at National Synchrotron Radiation Centre Solaris (NSRC Solaris), two units (one for each front end) of X-ray Beam Position Monitors (XBPM) have been installed as a diagnostic tool enabling for measurement of photon beam position. Hardware units of XBPM were manufactured, delivered, and eventually installed in Solaris by FMB Berlin. In order to get readouts of beam position from XBPM units, Libera Photon 2016 controller has been used as a complementary electronic device. Since XBPM units are supposed to be used along with the insertion device, an on-site Libera calibration was necessary. Libera’s calibration required few iterations of scans involving gap and phase movement of insertion devices at the 4th and 6th sections of the Solaris ring. The main focus was put on the derivation of Kx, and Ky coefficients. The content of this document describes step by step the procedure of Libera’s Kx, Ky coefficients value derivation at NSRC Solaris.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB249

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paper received ※ 19 May 2021 paper accepted ※ 17 July 2021 issue date ※ 13 August 2021

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THPAB270

Pair Spectrometer for FACET-II

electron, positron, scattering, detector

4336

B. Naranjo, G. Andonian, A. Fukasawa, N. Majernik, M.H. Oruganti, J.B. Rosenzweig, Y. Sakai, O. Williams, M. Yadav
UCLA, Los Angeles, California, USA
N. Cavanagh, G. Sarri
Queen’s University of Belfast, Belfast, Northern Ireland, United Kingdom
A. Di Piazza, C.H. Keitel
MPI-K, Heidelberg, Germany
E. Gerstmayr, S. Meuren, D.A. Reis, D.W. Storey, V. Yakimenko
SLAC, Menlo Park, California, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA
C. Nielsen
AU, Aarhus, Denmark

Funding: DARPA GRIT Contract 20204571, DOE HEP Grant DE-SC0009914
We present the design of a pair spectrometer for use at FACET-II, where there is a need for spectroscopy of photons having energies up to 10 GeV. Incoming gammas are converted to high-energy positron-electron pairs, which are then subsequently analyzed in a dipole magnet. These charged particles are then recorded in arrays of acrylic Cherenkov counters, which are significantly less sensitive to background x-rays than scintillator counters in this case. To reconstruct energies of single high-energy photons, the spectrometer has a sensitivity to single positron-electron pairs. Even in this single-photon limit, there is always some low-energy continuum present, so spectral deconvolution is not trivial, for which we demonstrate a maximum likelihood reconstruction. Finally, end-to-end simulations of experimental scenarios, together with anticipated backgrounds, are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB270

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paper received ※ 20 May 2021 paper accepted ※ 28 July 2021 issue date ※ 18 August 2021

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THPAB273

Spectral Reconstruction for FACET-II Compton Spectrometer

network, electron, site, positron

4346

Y. Zhuang, B. Naranjo, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, USA

Funding: This work was supported by DOE Contract DE-SC0009914, NSF Grant No. PHY-1549132, and DARPA GRIT Contract 20204571.
The Compton spectrometer under development at UCLA for FACET-II is a versatile tool to analyze gamma-ray spectra in a single shot, in which the energy and angular position of the incoming photons are recorded by observing the momenta and position of Compton scattered electrons. We present methods to reconstruct the primary spectrum from these data via machine learning and the EM Algorithm. A multi-layer fully connected neural network is used to perform the regression task of reconstructing both the double-differential spectrum and the photon energy spectrum incident with zero angular offset. We present the expected performance of these techniques, concentrating on the achievable energy resolution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB273

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paper received ※ 20 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021

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THPAB276

X-Ray Double Slit Interferometer Progress at CLS

synchrotron, simulation, storage-ring, emittance

4349

N.A. Simonson, Y. Yousefi Sigari
University of Saskatchewan, Saskatoon, Canada
M.J. Boland
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source (CLS) is a 3rd generation synchrotron that is used to produce extremely bright synchrotron light that can be used for research. The light at the CLS is produced by an electron storage ring that has an emittance of 20 nm. A 4th generation synchrotron (CLS2) is planned which will reduce the emittance to less than 1 nm and thus reduce the transverse beam size significantly, making it very challenging to measure. A double slit interferometer can be used to measure small transverse beam sizes, as first described by Mitsuhashi. An x-ray double slit interferometer will be designed and tested at the current CLS with the goal of using this setup at CLS2.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB276

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paper received ※ 20 May 2021 paper accepted ※ 23 July 2021 issue date ※ 01 September 2021

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THPAB291

DYVACS (DYnamic VACuum Simulation) Code: Gas Density Profiles in Presence of Electron Cloud in the LHC

electron, proton, vacuum, injection

4373

S. Bilgen, B. Mercier, G. Sattonnay
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
V. Baglin
CERN, Meyrin, Switzerland

The computation of residual gas density profiles in particle accelerators is an essential task to optimize beam pipes and vacuum system design. In a hadron collider such as the LHC, the beam induces dynamic effects due to ion, electron, and photon-stimulated gas desorption. The well-known VASCO* code developed at CERN in 2004 is already used to estimate vacuum stability and density profiles in steady-state conditions. Nevertheless, some phenomena are not taken into account such as the ionization of residual gas by the electron clouds and the evolution of the electronic density related to the electron cloud build-up. Therefore, we propose an upgrade of this code by introducing electron cloud maps** to estimate the electron density and the ionization of gas by electrons leading to an increase of induced desorption. The pressure evolution computed with DYVACS reproduces with good accuracy the experimental pressure recorded in the VPS beam pipes sector*** of the LHC from the proton beam injection to the stable beam period. Additionally, DYVACS can also be used as a predictive tool to compute the pressure evolution in the beam pipes for Future Circular Colliders (FCC-hh or -ee).
* A. Rossi, Tech. Report, LHC Project Note 341
** T. Demma et al Phys. Rev. Acceler. and Beams 10, 114401 (2007)
*** B. Henrist et al, Proc. IPAC2014, Dresden

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB291

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 31 August 2021

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