NAPAC2022 - List of Keywords (radiation)

Paper	Title	Other Keywords	Page
MOYE5	In Situ Plasma Processing of Superconducting Cavities at JLab	cavity, plasma, cryomodule, HOM	22
	T. Powers, N.C. Brock, T.D. Ganey JLab, Newport News, Virginia, USA
	Jefferson Lab has an ongoing R&D program in plasma processing which is close to going into production processing in the CEBAF accelerator. Plasma processing is a common technique for removing hydrocarbons from surfaces, which increases the work function and reduces the secondary emission coefficient. Unlike helium processing which relies on ion bombardment of the field emitters, plasma processing uses free oxygen produced in the plasma to break down the hydrocarbons on the surface of the cavity. The initial focus of the effort was processing C100 cavities by injecting RF power into the HOM coupler ports. Results from processing cryomodule in the cryomodule test bunker as well as vertical test results will be presented. We plan to start processing cryomodules in the CEBAF tunnel within the next year. The goal will be to improve the operational gradients and the energy margin of the linacs. This work will describe the systems and methods used at JLAB for processing cavities using an argon oxygen gas mixture. Before and after plasma processing results will also be presented.
	Slides MOYE5 [2.679 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOYE5
About •	Received ※ 01 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 01 October 2022
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MOZD2	Preliminary Study of a High Gain THz FEL in a Recirculating Cavity	electron, undulator, FEL, GUI	30
	A.C. Fisher, P. Musumeci UCLA, Los Angeles, California, USA
	The THz gap is a region of the electromagnetic spectrum where high average and peak power radiation sources are scarce while at the same time scientific and industrial applications are growing in demand. Free-electron laser coupling in a magnetic undulator is one of the best options for radiation generation in this frequency range, but slippage effects require the use of relatively long and low current electron bunches to drive the THz FEL, limiting amplification gain and output peak power. Here we use a circular waveguide in a 0.96 m strongly tapered helical undulator to match the radiation and e-beam velocities, allowing resonant energy extraction from an ultrashort 200 pC 5.5 MeV electron beam over an extended distance. E-beam energy measurements, supported by energy and spectral measurement of the THz FEL radiation, indicate an average energy efficiency of ~ 10%, with some particles losing > 20% of their initial kinetic energy.
	Slides MOZD2 [7.005 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOZD2
About •	Received ※ 04 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 13 August 2022
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MOPA02	Activation of the IBA Proteus One Proton Therapy Beamline Using BDSIM and FISPACT-II	proton, neutron, shielding, simulation	59
	E. Ramoisiaux, E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse, M. Vanwelde ULB, Bruxelles, Belgium C. Hernalsteens CERN, Meyrin, Switzerland
	Cyclotron-based proton therapy systems generate large fluxes of secondary particles due to the beam interactions with the beamline elements, with the energy degrader being the dominant source. Compact systems exacerbate these challenges for concrete shielding and beamline element activation. Our implementation of the Rigorous Two-Step method uses Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code, for primary and secondary particles transport and fluence scoring, and FISPACT-II for time-dependent nuclear inventory and solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system, for which a complete model has been built, validated, and used for shielding activation simulations. We detail the first simulations of the activation on quadrupole magnets in high-fluence locations downstream of the degrader. Results show the evolution of the long-lived nuclide concentrations for short and long timescales throughout the facility lifetime for a typical operation scenario.
	Poster MOPA02 [0.553 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA02
About •	Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 19 August 2022 — Issue date ※ 21 September 2022
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MOPA18	Residual Dose and Environmental Monitoring for the Fermilab Main Injector Tunnel Using the Data Acquisition Logging Engine (Dale)	survey, detector, proton, operation	87
	N. Chelidze, R. Ainsworth, B.C. Brown, D. Capista, K.J. Hazelwood, D.K. Morris, M.J. Murphy Fermilab, Batavia, Illinois, USA
	Funding: Fermi National Accelerator Laboratory The Recycler and the Main Injector are part of the Fermilab Accelerator complex used to deliver proton beam to the different experiments. It is very important to control and minimize losses in both machines during operation, to reduce personnel dose from residual activation and to preserve component lifetime. To minimize losses, we need to identify the loss points and adjust the components accordingly. The Data Acquisition Loss Engine (DALE) platform has been developed within the Main Injector department and upgraded throughout the years. DALE is used to survey the entire enclosure for residual dose rates and environmental readings when unrestricted access to the enclosure is possible. Currently DALE has two radiation meters, which are aligned along each machine, so loss points can be identified for both at the same time. DALE attaches to the enclosure carts and is continuously in motion monitoring dose rates and other environmental readings. In this paper we will describe how DALE is used to provide radiation maps of the residual dose rates in the enclosure. We will also compare the loss points with the Beam Loss monitor data.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA18
About •	Received ※ 02 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 21 September 2022
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MOPA34	Noise in Intense Electron Bunches	electron, laser, FEL, experiment	128
	S. Nagaitsev, D.R. Broemmelsiek, J.D. Jarvis, A.H. Lumpkin, J. Ruan, G.W. Saewert, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA Z. Huang, G. Stupakov SLAC, Menlo Park, California, USA Y.K. Kim University of Chicago, Chicago, Illinois, USA
	We report on our investigations into density fluctuations in electron bunches. Noise and density fluctuations in relativistic electron bunches, accelerated in a linac, are of critical importance to various Coherent Electron Cooling (CEC) concepts as well as to free-electron lasers (FELs). For CEC, the beam noise results in additional diffusion that counteracts cooling. In SASE FELs, a microwave instability starts from the initial noise in the beam and eventually leads to the beam microbunching yielding coherent radiation, and the initial noise in the FEL bandwidth plays a useful role. In seeded FELs, in contrast, such noise interferes with the seed signal, so that reducing noise at the initial seed wavelength would lower the seed laser power requirement. Status of the project will be presented.
	Poster MOPA34 [0.638 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA34
About •	Received ※ 10 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 14 August 2022 — Issue date ※ 24 August 2022
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MOPA45	Vacuum Electron Devices in the 88-Inch Cyclotron	cyclotron, ECR, electron, plasma	154
	M. Kireeff Covo, J.Y. Benitez, P. Bloemhard, J.P. Garcia, B. Ninemire, L. Phair, D.S. Todd, D.Z. Xie LBNL, Berkeley, California, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC02-05CH11231 The 88-Inch Cyclotron at Lawrence Berkeley National Laboratory is a sector-focused cyclotron that has light- and heavy-ion capabilities and supports a local research program in Nuclear Science and is the home of the Berkeley Accelerator Space Effects Facility, which studies effects of radiation on microelectronics, optics, materials, and cells. The cyclotron utilizes several vacuum electron devices (VEDs) in different systems, mainly to convey plasma heating, high power RF generation, and high-voltage and current DC power generation. VEDs have been proven reliable, robust, and radiation resistant. They also have wide range, good response against transients, and stable operation with load mismatch during system tuning, instabilities, or breakdowns. The paper will describe applications of these devices in the 88-Inch Cyclotron
	Poster MOPA45 [1.434 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA45
About •	Received ※ 02 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 12 September 2022
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MOPA57	Online Models for X-Ray Beamlines	optics, emittance, synchrotron, controls	170
	B. Nash, D.T. Abell, M.V. Keilman, P. Moeller, I.V. Pogorelov RadiaSoft LLC, Boulder, Colorado, USA Y. Du, A. Giles, J. Lynch, T. Morris, M.S. Rakitin, A. Walter BNL, Upton, New York, USA N.B. Goldring STATE33 Inc., Portland, Oregon, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, under Award Number DE-SC0020593 X-ray beamlines transport synchrotron radiation from the magnetic source to the sample at a synchrotron light source. Alignment of elements such as mirrors and gratings are often done manually and can be quite time consuming. The use of photon beam models during operations is not common in the same way that they are used to great benefit for particle beams in accelerators. Linear and non-linear optics including the effects of coherence may be computed from source properties and augmented with measurements. In collaboration with NSLS-II, we are developing software tools and methods to include the model of the x-ray beam as it passes on its way to the sample. We are integrating the Blue-Sky beamline control toolkit with the Sirepo interface to several x-ray optics codes. Further, we are developing a simplified linear optics approach based on a Gauss-Schell model and linear canonical transforms as well as developing Machine Learning models for use directly from diagnostics data. We present progress on applying these ideas on NSLS-II beamlines and give a future outlook on this rather large and open domain for technological development.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA57
About •	Received ※ 27 July 2022 — Revised ※ 02 August 2022 — Accepted ※ 07 August 2022 — Issue date ※ 11 August 2022
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MOPA63	Multiphysics Simulation of the Thermal Response of a Nanofibrous Target in a High-Intensity Beam	target, simulation, experiment, proton	185
	W.J. Asztalos IIT, Chicago, Illinois, USA S.K. Bidhar, F. Pellemoine Fermilab, Batavia, Illinois, USA P. Rath IIT Bhubaneswar, Jatni, India Y. Torun Illinois Institute of Technology, Chicago, Illlinois, USA
	Nanofibrous structures are of high interest to the fields of engineering and materials science, and investigation of their properties as well as discovery of novel applications for them both constitute lively areas of research. A very promising application of nanofiber mats lies in the field of accelerator technology: beam targets made from nanofiber mats offer a solution to the problem of advancing the "intensity frontier"–-the limit on the beam intensities that can be realized in fixed target experiments and neutrino production facilities. However, testing has shown that the survivability of these nanofiber targets depends strongly on their manufacturing parameters, such as the packing density of fibers. In this work, we will use multiphysics simulations to perform a thermal study on how nanofiber targets react to high intensity beams, so that the dependency of the targets’ lifetime on their construction parameters can be better understood.
	Poster MOPA63 [3.656 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA63
About •	Received ※ 14 July 2022 — Revised ※ 02 August 2022 — Accepted ※ 04 August 2022 — Issue date ※ 25 August 2022
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MOPA70	Film Dosimetry Characterization of the Research Linac at the University of Maryland	electron, linac, vacuum, experiment	203
	A.S. Johnson, L.T. Gilde, M.K. Hottinger, T.W. Koeth UMD, College Park, Maryland, USA
	A heavily modified Varian linac was installed as part of the University of Maryland Radiation Facilities in the early 1980s. The electron linac was initially used for materials testing and pulsed radiolysis. Overtime, diagnostics such as a spectrometer magnet and scintillator screens have been removed, limiting the ability to describe the electron beam. The beamline is currently configured with a thin titanium window to allow the electrons to escape the vacuum region and interact with samples in air. A calibrated film dosimetry system was used to characterize the transverse beam dimensions and uniformity in air. The results of these experimental measurements will be described in this paper.
	Poster MOPA70 [3.423 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA70
About •	Received ※ 27 July 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 20 August 2022
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TUXD3	Production Pathways for Medically Interesting Isotopes	target, proton, neutron, isotope-production	271
	L. Rosado Del Rio University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico L.F. Dabill Coe College, Cedar Rapids, Iowa, USA A. Hutton JLab, Newport News, Virginia, USA
	Funding: LR was supported by the U.S. NSF REU at Old Dominion University Grant No. 1950141. AH was supported by the U.S. DOE, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177 Radioisotopes are commonly used in nuclear medicine for treating cancer and new, more effective treatment options are always desired. As a result, there is a national need for new radioisotopes and ways to produce them. A computer program was created that evaluates the daughters for all known reactions of projectiles (gamma rays, protons or neutrons) with every stable target isotope by comparing the cross-sections for each reaction at a desired energy, and outputs a list of the potential daughter isotopes that are most likely to be generated. The program then evaluates the decay chains of these daughters to provide a list of the possible decay chains that contain the radioisotope of interest. By knowing the daughter production and decay chain for each isotope, it is possible to go from the desired radioisotope to the stable isotope that can be used as a target for its production. This project would facilitate the search for new pathways to creating useful theranostic isotopes.
	Slides TUXD3 [0.591 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUXD3
About •	Received ※ 17 July 2022 — Revised ※ 01 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 25 August 2022
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TUPA30	Development of a Compact 2D Carbon Beam Scanner for Cancer Therapy	proton, power-supply, simulation, magnet-design	417
	B. Mustapha, A. Barcikowski, J.A. Nolen ANL, Lemont, Illinois, USA V.P. Derenchuk, P. Osucha ProNova Solutions, Knoxville, USA N. Tsoupas BNL, Upton, New York, USA
	Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC02-06CH11357. This research was support through the DOE’s Accelerator Stewardship program. A novel trapezoidal coil 2D carbon beam scanner has been designed, and a prototype has been successfully developed and tested. The field performance of the magnet has been characterized and it is in excellent agreement with the simulations. A better than 1% field uniformity in both planes has been achieved within the useful aperture of the magnet. This represents a significant improvement over the prior art of the elephant-ear scanner design. A comparison of the two designs and the results from the new trapezoidal-coil design will be presented and discussed. Higher power and online beam testing are planned in the near future.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA30
About •	Received ※ 25 July 2022 — Revised ※ 14 August 2022 — Accepted ※ 15 August 2022 — Issue date ※ 25 August 2022
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TUPA37	A Distributed Beam Loss Monitor Based upon Activation of Oxygen in Deionised Cooling Water	storage-ring, detector, photon, experiment	433
	K.P. Wootton 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. We propose a novel beam loss detection scheme whereby activation of deionised cooling water is used to observe elevated radiation around the APS storage ring. This is based on radioactivation of oxygen within deionised cooling water by gamma rays above 10 MeV and neutrons above 15 MeV. Losses would be detected using a gamma ray detector monitoring process water flow out of the accelerator enclosure. We anticipate that this could be used to provide a segmented, distributed loss monitor system covering the accelerator components closest to locations where radiation is generated.
	Poster TUPA37 [0.528 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA37
About •	Received ※ 02 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 26 September 2022
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TUPA53	Modeling of Nonlinear Beam Dynamics via a Novel Particle-Mesh Method and Surrogate Models with Symplectic Neural Networks	simulation, network, electron, synchrotron-radiation	462
	C.-K. Huang, O. Beznosov, J.W. Burby, B.E. Carlsten, G.A. Dilts, J. Domine, R. Garimella, A. Kim, T.J. Kwan, H.N. Rakotoarivelo, R.W. Robey, B. Shen, Q. Tang LANL, Los Alamos, New Mexico, USA F.Y. Li New Mexico Consortium, Los Alamos, USA
	Funding: Work supported by the LDRD program at Los Alamos National Laboratory and the ASCR SciML program of DOE. The self-consistent nonlinear dynamics of a relativistic charged particle beam, particularly through the interaction with its complete self-fields, is a fundamental problem underpinning many accelerator design issues in high brightness beam applications, as well as the development of advanced accelerators. A novel self-consistent particle-mesh code, CoSyR [1], is developed based on a Lagrangian method for the calculation of the beam particles’ radiation near-fields and associated beam dynamics. Our recent simulations reveal the slice emittance growth in a bend and complex interplay between the longitudinal and transverse dynamics that are not captured in the 1D longitudinal static-state Coherent Synchrotron Radiation (CSR) model. We further show that surrogate models with symplectic neural networks can be trained from simulation data with significant time-savings for the modeling of nonlinear beam dynamics effects. Possibility to extend such surrogate models for the study of spin-orbital coupling is also briefly discussed. [1] C.-K. Huang et al., Nucl. Instruments Methods Phys. Res. Sect. A, vol. 1034, p. 166808, 2022.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA53
About •	Received ※ 25 July 2022 — Revised ※ 03 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 11 August 2022
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TUPA72	Comparison Study on First Bunch Compressor Schemes by Conventional and Double C-Chicane for MaRIE XFEL	dipole, emittance, electron, FEL	496
	H. Xu, P.M. Anisimov, L.D. Duffy, Q.R. Marksteiner LANL, Los Alamos, New Mexico, USA
	Funding: Laboratory Directed Research and Development program of Los Alamos National Laboratory, project number 20200287ER. We report our comparison study on the first stage electron bunch compression schemes at 750 MeV using a conventional and a double C-chicane for the X-ray free electron laser (XFEL) under development for the Matter-Radiation Interactions in Extremes (MaRIE) initiative at Los Alamos National Laboratory. Compared to the performance of the conventional C-chicane bunch compressor, the double C-chicane scheme exhibits the capability of utilizing the transverse momentum shift induced by the coherent synchrotron radiation in the second C-chicane to compensate that generated in the first C-chicane, resulting in a compressed electron bunch with minimized transverse momentum shift along the beam. It is also found that the double C-chicane scheme can be designed to significantly better preserve the beam emittance in the course of the bunch compression. This is particularly beneficial for the MaRIE XFEL whose lasing performance critically depends on the preservation of the ultralow beam emittance.
	Poster TUPA72 [1.339 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA72
About •	Received ※ 01 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 15 August 2022
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TUPA74	Numerical Calculations of Wave Generation from a Bunched Electron Beam in Space	electron, plasma, simulation, experiment	502
	H. Xu, G.L. Delzanno, L.D. Duffy, Q.R. Marksteiner, G.D. Reeves LANL, Los Alamos, New Mexico, USA
	Funding: This project was supported by the Laboratory Directed Research and Development program of Los Alamos National Laboratory. We present our numerical approach and preliminary results of the calculations of whistler and X-mode wave generation by a bunched electron beam in space. The artificial generation of whistler and X-mode plasma waves in space is among the candidate techniques to accomplish the radiation belt remediation (RBR), in an effort to precipitate energetic electrons towards the atmosphere to reduce their threat to low-Earth orbit satellites. Free-space propagation of an electron pulse in a constant background magnetic field was simulated with the CST particle-in-cell (PIC) solver, with the temporal evolution of the beam recorded. The SpectralPlasmaSolver (SPS) was then modified to use the recorded electron pulse propagation to calculate the real-time plasma waves generated by the beam. SPS simulation results of the wave generation for the upcoming Beam-PIE experiment as well as an ideal bunched electron beam are shown.
	Poster TUPA74 [0.963 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA74
About •	Received ※ 18 July 2022 — Revised ※ 02 August 2022 — Accepted ※ 07 August 2022 — Issue date ※ 08 August 2022
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TUPA84	Reconstructing Beam Parameters from Betatron Radiation Through Machine Learning and Maximum Likelihood Estimation	betatron, simulation, diagnostics, plasma	527
	S. Zhang, N. Majernik, B. Naranjo, J.B. Rosenzweig, M. Yadav UCLA, Los Angeles, California, USA Ö. Apsimon, C.P. Welsch, M. Yadav The University of Liverpool, Liverpool, United Kingdom
	Funding: US Department of Energy, Division of High Energy Physics, under Contract No. DE-SC0009914. The dense drive beam used in plasma wakefield acceleration generates a linear focusing force that causes electrons inside the witness beam to undergo betatron oscillations, giving rise to betatron radiation. Because information about the properties of the beam is encoded in the betatron radiation, measurements of the radiation such as those recorded by the UCLA-built Compton spectrometer can be used to reconstruct beam parameters. Two possible methods of extracting information about beam parameters from measurements of radiation are machine learning (ML), which is increasingly being implemented for different fields of beam diagnostics, and a statistical technique known as maximum likelihood estimation (MLE). We assess the ability of both machine learning and MLE methods to accurately extract beam parameters from measurements of betatron radiation.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA84
About •	Received ※ 02 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 05 October 2022
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TUPA87	Simulations for the Space Plasma Experiments at the SAMURAI Lab	electron, plasma, simulation, experiment	539
	P. Manwani, H.S. Ancelin, A. Fukasawa, G.E. Lawler, N. Majernik, B. Naranjo, J.B. Rosenzweig, Y. Sakai, O. Williams UCLA, Los Angeles, California, USA G. Andonian RadiaBeam, Santa Monica, California, USA
	Funding: This work was performed with support of the US Department of Energy under Contract No. DE-SC0017648 and DESC0009914, and the DARPA GRIT Contract 20204571 Plasma wakefield acceleration using the electron linear accelerator test facility, SAMURAI, can be used to study the Jovian electron spectrum due to the high energy spread of the beam after the plasma interaction. The SAMURAI RF facility which is currently being constructed and commissioned at UCLA, is is capable of producing beams with 10 MeV energy, 2 nC charge, and 200 fsec bunch lengths with a 4 um emittance. Particle-in-cell (PIC) simulations are used to study the beam spectrum that would be generated from plasma interaction. Experimental methods and diagnostics are discussed in this paper.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA87
About •	Received ※ 04 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 06 September 2022
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WEXD3	Map Tracking Including the Effect of Stochastic Radiation	emittance, lattice, damping, photon	548
	D. Sagan, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA E. Forest KEK, Ibaraki, Japan
	Funding: Department of Energy Using transfer maps to simulate charged particle motion in accelerators is advantageous since it is much faster than tracking step-by-step. One challenge to using transfer maps is to properly include radiation effects. The effect of radiation can be divided into deterministic and stochastic parts. While computation of the deterministic effect has been previously reported, handling of the stochastic part has not. In this paper, an algorithm for including the stochastic effect is presented including taking into account the finite opening angle of the emitted photons. A comparison demonstrates the utility of this approach. Generating maps which include radiation has been implemented in the PTC software library which is interfaced to the Bmad toolkit.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD3
About •	Received ※ 06 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 24 August 2022
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WEPA04	Simulating Two Dimensional Transient Coherent Synchrotron Radiation in Julia	synchrotron-radiation, GPU, synchrotron, emittance	627
	W. Lou, Y. Cai, C.E. Mayes SLAC, Menlo Park, California, USA
	Coherent Synchrotron Radiation (CSR) in bending magnets poses a limit for electron beams to reach high brightness in novel accelerators. While the longitudinal wakefield has been well studied in the one-dimensional CSR theory and implemented in various simulation codes, transverse wakefields have received less attention. Following the recently developed two and three-dimensional CSR theory, we developed software packages in Python and Julia to simulate the 2D CSR effects. The Python packages, PyCSR2D and PyCSR3D, utilize parallel processing in CPU to compute the steady-state CSR wakes. The Julia package, CSR2D.jl, additionally computes the 2D transient CSR wakes with GPU compatibility. We applied these codes to simulate the 2D CSR effects in the LCLS-II and FACET-II particle accelerators at the SLAC National Accelerator Laboratory.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA04
About •	Received ※ 03 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 18 August 2022
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WEPA08	Design and Operation Experience of a Multi-Collimator/YAG Screen Device on LCLS II Low Energy Beamline	wakefield, simulation, electron, gun	631
	X. Liu, C. Adolphsen, M. Santana-Leitner, L. Xiao, F. Zhou SLAC, Menlo Park, California, USA
	During the commissioning of the normal conducting VHF RF gun of LCLS II, it was observed that field emission (dark current) of roughly 2 µA level was present under normal operation of the gun. While the dark current of this level is deemed manageable with existing beamline configurations, it is desired in precaution to add a collimator on the low energy beamline to block the dark current, being concerned that the dark current situation might worsen with time. Since no spare longitudinal space is available, the new device takes place of the existing YAG screen. The new device is made of a 15 mm thick copper plate, with four round apertures of 6, 8, 10, and 12 mm radius respectively. At the end of the collimator plate, features are made for clamping two YAG screens and mounting their corresponding mirrors for beam/halo profile imaging. The collimator plate is electrically insulated from the chamber so that it can also be used for measuring the dark current. A motor-driven UHV compatible linear translator shifts the device between positions. Besides design details, related thermal, beam dynamics, and radiation analyses as well as operation experience will be presented. * Work supported by US DOE under contract AC02-76SF00515.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA08
About •	Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 13 September 2022
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WEPA25	Field Emission Mitigation in CEBAF SRF Cavities Using Deep Learning	cavity, detector, neutron, linac	676
	K. Ahammed, J. Li ODU, Norfolk, Virginia, USA A. Carpenter, R. Suleiman, C. Tennant, L.S. Vidyaratne JLab, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. The Continuous Electron Beam Accelerator Facility (CEBAF) operates hundreds of superconducting radio frequency (SRF) cavities in its two main linear accelerators. Field emission can occur when the cavities are set to high operating RF gradients and is an ongoing operational challenge. This is especially true in newer, higher gradient SRF cavities. Field emission results in damage to accelerator hardware, generates high levels of neutron and gamma radiation, and has deleterious effects on CEBAF operations. So, field emission reduction is imperative for the reliable, high gradient operation of CEBAF that is required by experimenters. Here we explore the use of deep learning architectures via multilayer perceptron to simultaneously model radiation measurements at multiple detectors in response to arbitrary gradient distributions. These models are trained on collected data and could be used to minimize the radiation production through gradient redistribution. This work builds on previous efforts in developing machine learning (ML) models, and is able to produce similar model performance as our previous ML model without requiring knowledge of the field emission onset for each cavity.
	Poster WEPA25 [1.586 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA25
About •	Received ※ 01 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 05 August 2022 — Issue date ※ 20 September 2022
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WEPA44	Compact Inter-Undulator Diagnostic Assembly for TESSA-515	undulator, quadrupole, electron, diagnostics	732
	T.J. Hodgetts, R.B. Agustsson, Y.C. Chen, A.Y. Murokh, M. Ruelas RadiaBeam, Santa Monica, California, USA P.E. Denham, A.C. Fisher, J. Jin, P. Musumeci, Y. Park UCLA, Los Angeles, USA
	Funding: DOE grant DE-SC0009914, DE-SC0018559, and DE-SC0017102. Beamline space is a very expensive and highly sought-after commodity, which makes the creation of compact integrated optics and diagnostics extremely valuable. The FAST- GREENS experimental program aims at demonstrating 10 % extraction efficiency from a relativistic electron beam using four helical undulators operating in the high gain TESSA regime. The inter-undulator gap needs to be as short as possible (17 cm in the current plans) to maximize the output power. Within this short distance, we needed to fit two focusing quadrupoles, a variable strength phase shifter, a transverse profile monitor consisting of a YAG-OTR combination for co-aligning the electron beam and laser, and an ion pump. By making the quadrupoles tunable with a variable gradient, in combination with vertical displacement, we can meet the optics requirements of matching the beam transversely to the natural focusing of the undulators. The two quadrupoles in conjunction with the electromagnetic dipole also serve as a phase shifter to realign the radiation and the bunching before each undulator section. This paper will discuss the mechanical design of this inter-undulator break section and its components.
	Poster WEPA44 [0.752 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA44
About •	Received ※ 27 July 2022 — Revised ※ 03 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 11 August 2022
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WEPA73	Numerical Studies of Geometric Impedance at NSLS-II with GdfidL and ECHO3D	impedance, simulation, vacuum, wakefield	802
	A. Khan, M. Seegitz, V.V. Smaluk, R.J. Todd BNL, Upton, New York, USA A. Blednykh Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
	The beam intensity in future low-emittance light sources with small gap wigglers and undulators is limited by the effects of short-range wakefields, especially by the beam-induced heating of the vacuum chamber components. We have cross-checked two electromagnetic solvers, GdfidL and ECHO3D, by simulation of the short-range wakefields in the NSLS-II flange absorber and in the taper transition of an in-vacuum undulator to test the consistency and precision of the wakefield models.
	Poster WEPA73 [1.057 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA73
About •	Received ※ 01 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 01 September 2022
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THYD6	Arrival Time and Energy Jitter Effects on the Performance of X-Ray Free Electron Laser Oscillator	FEL, cavity, electron, laser	866
	G. Tiwari BNL, Upton, New York, USA K.-J. Kim, R.R. Lindberg ANL, Lemont, Illinois, USA K.-J. Kim University of Chicago, Chicago, Illinois, USA
	Funding: U.S. Dept. of Energy Office of Sciences under Contract No. DE-AC02-06CH11357. We report on the effects of electron beam arrival time and energy jitter on the power level and the fluctuations of the output of an X-ray FEL oscillator (XFELO). For this study, we apply the FEL driven paraxial resonator model of XFELO along with an analytical reflectivity profile to mimic the phase shift and spectral filtering effects of Bragg-crystals. The thresholds for acceptable timing jitters and energy jitters are determined in terms of the fluctuations of the steady-state power output. We explore potential ways to mitigate the power output fluctuations in the presence of unavoidable electron beam jitters.
	Slides THYD6 [1.935 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-THYD6
About •	Received ※ 01 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 03 October 2022
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THYE4	Development of an Ultra-Low Vibration Cryostat Based on a Closed-Cycle Cryocooler	vacuum, cryogenics, instrumentation, synchrotron	874
	R.W. Roca Illinois Institute of Technology, Chicago, Illinois, USA E.W. Knight, R.A. Kostin, Y. Zhao Euclid TechLabs, Solon, Ohio, USA
	Low temperature and low vibration cryostats are useful in a variety of applications such as x-ray diffraction, quantum computing, x-ray monochromators and cryo-TEMs. In this project, we explore an ultra-low vibration cryostat with the cooling provided by a closed cycle cryocooler. Closed-cycle cryocoolers inevitably introduce vibrations into the system, and in this project, flexible copper braiding was used to decouple vibrations and provide cooling at the same time. In order to develop the cryostat, capacity map of a two stage Sumitomo cryocooler was measured as well as vibration transmission through different copper braids using an IR interferometer. This paper covers the capacity map and vibration measurements in the first prototype.
	Slides THYE4 [4.989 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-THYE4
About •	Received ※ 16 July 2022 — Revised ※ 10 August 2022 — Accepted ※ 20 August 2022 — Issue date ※ 12 September 2022
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Paper

Title

Other Keywords

Page

MOYE5

In Situ Plasma Processing of Superconducting Cavities at JLab

cavity, plasma, cryomodule, HOM

22

T. Powers, N.C. Brock, T.D. Ganey
JLab, Newport News, Virginia, USA

Jefferson Lab has an ongoing R&D program in plasma processing which is close to going into production processing in the CEBAF accelerator. Plasma processing is a common technique for removing hydrocarbons from surfaces, which increases the work function and reduces the secondary emission coefficient. Unlike helium processing which relies on ion bombardment of the field emitters, plasma processing uses free oxygen produced in the plasma to break down the hydrocarbons on the surface of the cavity. The initial focus of the effort was processing C100 cavities by injecting RF power into the HOM coupler ports. Results from processing cryomodule in the cryomodule test bunker as well as vertical test results will be presented. We plan to start processing cryomodules in the CEBAF tunnel within the next year. The goal will be to improve the operational gradients and the energy margin of the linacs. This work will describe the systems and methods used at JLAB for processing cavities using an argon oxygen gas mixture. Before and after plasma processing results will also be presented.

Slides MOYE5 [2.679 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOYE5

About •

Received ※ 01 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 01 October 2022

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MOZD2

Preliminary Study of a High Gain THz FEL in a Recirculating Cavity

electron, undulator, FEL, GUI

30

A.C. Fisher, P. Musumeci
UCLA, Los Angeles, California, USA

The THz gap is a region of the electromagnetic spectrum where high average and peak power radiation sources are scarce while at the same time scientific and industrial applications are growing in demand. Free-electron laser coupling in a magnetic undulator is one of the best options for radiation generation in this frequency range, but slippage effects require the use of relatively long and low current electron bunches to drive the THz FEL, limiting amplification gain and output peak power. Here we use a circular waveguide in a 0.96 m strongly tapered helical undulator to match the radiation and e-beam velocities, allowing resonant energy extraction from an ultrashort 200 pC 5.5 MeV electron beam over an extended distance. E-beam energy measurements, supported by energy and spectral measurement of the THz FEL radiation, indicate an average energy efficiency of ~ 10%, with some particles losing > 20% of their initial kinetic energy.

Slides MOZD2 [7.005 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOZD2

About •

Received ※ 04 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 13 August 2022

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MOPA02

Activation of the IBA Proteus One Proton Therapy Beamline Using BDSIM and FISPACT-II

proton, neutron, shielding, simulation

59

E. Ramoisiaux, E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse, M. Vanwelde
ULB, Bruxelles, Belgium
C. Hernalsteens
CERN, Meyrin, Switzerland

Cyclotron-based proton therapy systems generate large fluxes of secondary particles due to the beam interactions with the beamline elements, with the energy degrader being the dominant source. Compact systems exacerbate these challenges for concrete shielding and beamline element activation. Our implementation of the Rigorous Two-Step method uses Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code, for primary and secondary particles transport and fluence scoring, and FISPACT-II for time-dependent nuclear inventory and solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system, for which a complete model has been built, validated, and used for shielding activation simulations. We detail the first simulations of the activation on quadrupole magnets in high-fluence locations downstream of the degrader. Results show the evolution of the long-lived nuclide concentrations for short and long timescales throughout the facility lifetime for a typical operation scenario.

Poster MOPA02 [0.553 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA02

About •

Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 19 August 2022 — Issue date ※ 21 September 2022

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MOPA18

Residual Dose and Environmental Monitoring for the Fermilab Main Injector Tunnel Using the Data Acquisition Logging Engine (Dale)

survey, detector, proton, operation

87

N. Chelidze, R. Ainsworth, B.C. Brown, D. Capista, K.J. Hazelwood, D.K. Morris, M.J. Murphy
Fermilab, Batavia, Illinois, USA

Funding: Fermi National Accelerator Laboratory
The Recycler and the Main Injector are part of the Fermilab Accelerator complex used to deliver proton beam to the different experiments. It is very important to control and minimize losses in both machines during operation, to reduce personnel dose from residual activation and to preserve component lifetime. To minimize losses, we need to identify the loss points and adjust the components accordingly. The Data Acquisition Loss Engine (DALE) platform has been developed within the Main Injector department and upgraded throughout the years. DALE is used to survey the entire enclosure for residual dose rates and environmental readings when unrestricted access to the enclosure is possible. Currently DALE has two radiation meters, which are aligned along each machine, so loss points can be identified for both at the same time. DALE attaches to the enclosure carts and is continuously in motion monitoring dose rates and other environmental readings. In this paper we will describe how DALE is used to provide radiation maps of the residual dose rates in the enclosure. We will also compare the loss points with the Beam Loss monitor data.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA18

About •

Received ※ 02 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 21 September 2022

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MOPA34

Noise in Intense Electron Bunches

electron, laser, FEL, experiment

128

S. Nagaitsev, D.R. Broemmelsiek, J.D. Jarvis, A.H. Lumpkin, J. Ruan, G.W. Saewert, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
Z. Huang, G. Stupakov
SLAC, Menlo Park, California, USA
Y.K. Kim
University of Chicago, Chicago, Illinois, USA

We report on our investigations into density fluctuations in electron bunches. Noise and density fluctuations in relativistic electron bunches, accelerated in a linac, are of critical importance to various Coherent Electron Cooling (CEC) concepts as well as to free-electron lasers (FELs). For CEC, the beam noise results in additional diffusion that counteracts cooling. In SASE FELs, a microwave instability starts from the initial noise in the beam and eventually leads to the beam microbunching yielding coherent radiation, and the initial noise in the FEL bandwidth plays a useful role. In seeded FELs, in contrast, such noise interferes with the seed signal, so that reducing noise at the initial seed wavelength would lower the seed laser power requirement. Status of the project will be presented.

Poster MOPA34 [0.638 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA34

About •

Received ※ 10 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 14 August 2022 — Issue date ※ 24 August 2022

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MOPA45

Vacuum Electron Devices in the 88-Inch Cyclotron

cyclotron, ECR, electron, plasma

154

M. Kireeff Covo, J.Y. Benitez, P. Bloemhard, J.P. Garcia, B. Ninemire, L. Phair, D.S. Todd, D.Z. Xie
LBNL, Berkeley, California, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC02-05CH11231
The 88-Inch Cyclotron at Lawrence Berkeley National Laboratory is a sector-focused cyclotron that has light- and heavy-ion capabilities and supports a local research program in Nuclear Science and is the home of the Berkeley Accelerator Space Effects Facility, which studies effects of radiation on microelectronics, optics, materials, and cells. The cyclotron utilizes several vacuum electron devices (VEDs) in different systems, mainly to convey plasma heating, high power RF generation, and high-voltage and current DC power generation. VEDs have been proven reliable, robust, and radiation resistant. They also have wide range, good response against transients, and stable operation with load mismatch during system tuning, instabilities, or breakdowns. The paper will describe applications of these devices in the 88-Inch Cyclotron

Poster MOPA45 [1.434 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA45

About •

Received ※ 02 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 12 September 2022

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MOPA57

Online Models for X-Ray Beamlines

optics, emittance, synchrotron, controls

170

B. Nash, D.T. Abell, M.V. Keilman, P. Moeller, I.V. Pogorelov
RadiaSoft LLC, Boulder, Colorado, USA
Y. Du, A. Giles, J. Lynch, T. Morris, M.S. Rakitin, A. Walter
BNL, Upton, New York, USA
N.B. Goldring
STATE33 Inc., Portland, Oregon, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, under Award Number DE-SC0020593
X-ray beamlines transport synchrotron radiation from the magnetic source to the sample at a synchrotron light source. Alignment of elements such as mirrors and gratings are often done manually and can be quite time consuming. The use of photon beam models during operations is not common in the same way that they are used to great benefit for particle beams in accelerators. Linear and non-linear optics including the effects of coherence may be computed from source properties and augmented with measurements. In collaboration with NSLS-II, we are developing software tools and methods to include the model of the x-ray beam as it passes on its way to the sample. We are integrating the Blue-Sky beamline control toolkit with the Sirepo interface to several x-ray optics codes. Further, we are developing a simplified linear optics approach based on a Gauss-Schell model and linear canonical transforms as well as developing Machine Learning models for use directly from diagnostics data. We present progress on applying these ideas on NSLS-II beamlines and give a future outlook on this rather large and open domain for technological development.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA57

About •

Received ※ 27 July 2022 — Revised ※ 02 August 2022 — Accepted ※ 07 August 2022 — Issue date ※ 11 August 2022

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MOPA63

Multiphysics Simulation of the Thermal Response of a Nanofibrous Target in a High-Intensity Beam

target, simulation, experiment, proton

185

W.J. Asztalos
IIT, Chicago, Illinois, USA
S.K. Bidhar, F. Pellemoine
Fermilab, Batavia, Illinois, USA
P. Rath
IIT Bhubaneswar, Jatni, India
Y. Torun
Illinois Institute of Technology, Chicago, Illlinois, USA

Nanofibrous structures are of high interest to the fields of engineering and materials science, and investigation of their properties as well as discovery of novel applications for them both constitute lively areas of research. A very promising application of nanofiber mats lies in the field of accelerator technology: beam targets made from nanofiber mats offer a solution to the problem of advancing the "intensity frontier"–-the limit on the beam intensities that can be realized in fixed target experiments and neutrino production facilities. However, testing has shown that the survivability of these nanofiber targets depends strongly on their manufacturing parameters, such as the packing density of fibers. In this work, we will use multiphysics simulations to perform a thermal study on how nanofiber targets react to high intensity beams, so that the dependency of the targets’ lifetime on their construction parameters can be better understood.

Poster MOPA63 [3.656 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA63

About •

Received ※ 14 July 2022 — Revised ※ 02 August 2022 — Accepted ※ 04 August 2022 — Issue date ※ 25 August 2022

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MOPA70

Film Dosimetry Characterization of the Research Linac at the University of Maryland

electron, linac, vacuum, experiment

203

A.S. Johnson, L.T. Gilde, M.K. Hottinger, T.W. Koeth
UMD, College Park, Maryland, USA

A heavily modified Varian linac was installed as part of the University of Maryland Radiation Facilities in the early 1980s. The electron linac was initially used for materials testing and pulsed radiolysis. Overtime, diagnostics such as a spectrometer magnet and scintillator screens have been removed, limiting the ability to describe the electron beam. The beamline is currently configured with a thin titanium window to allow the electrons to escape the vacuum region and interact with samples in air. A calibrated film dosimetry system was used to characterize the transverse beam dimensions and uniformity in air. The results of these experimental measurements will be described in this paper.

Poster MOPA70 [3.423 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA70

About •

Received ※ 27 July 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 20 August 2022

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TUXD3

Production Pathways for Medically Interesting Isotopes

target, proton, neutron, isotope-production

271

L. Rosado Del Rio
University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico
L.F. Dabill
Coe College, Cedar Rapids, Iowa, USA
A. Hutton
JLab, Newport News, Virginia, USA

Funding: LR was supported by the U.S. NSF REU at Old Dominion University Grant No. 1950141. AH was supported by the U.S. DOE, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177
Radioisotopes are commonly used in nuclear medicine for treating cancer and new, more effective treatment options are always desired. As a result, there is a national need for new radioisotopes and ways to produce them. A computer program was created that evaluates the daughters for all known reactions of projectiles (gamma rays, protons or neutrons) with every stable target isotope by comparing the cross-sections for each reaction at a desired energy, and outputs a list of the potential daughter isotopes that are most likely to be generated. The program then evaluates the decay chains of these daughters to provide a list of the possible decay chains that contain the radioisotope of interest. By knowing the daughter production and decay chain for each isotope, it is possible to go from the desired radioisotope to the stable isotope that can be used as a target for its production. This project would facilitate the search for new pathways to creating useful theranostic isotopes.

Slides TUXD3 [0.591 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUXD3

About •

Received ※ 17 July 2022 — Revised ※ 01 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 25 August 2022

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TUPA30

Development of a Compact 2D Carbon Beam Scanner for Cancer Therapy

proton, power-supply, simulation, magnet-design

417

B. Mustapha, A. Barcikowski, J.A. Nolen
ANL, Lemont, Illinois, USA
V.P. Derenchuk, P. Osucha
ProNova Solutions, Knoxville, USA
N. Tsoupas
BNL, Upton, New York, USA

Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC02-06CH11357. This research was support through the DOE’s Accelerator Stewardship program.
A novel trapezoidal coil 2D carbon beam scanner has been designed, and a prototype has been successfully developed and tested. The field performance of the magnet has been characterized and it is in excellent agreement with the simulations. A better than 1% field uniformity in both planes has been achieved within the useful aperture of the magnet. This represents a significant improvement over the prior art of the elephant-ear scanner design. A comparison of the two designs and the results from the new trapezoidal-coil design will be presented and discussed. Higher power and online beam testing are planned in the near future.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA30

About •

Received ※ 25 July 2022 — Revised ※ 14 August 2022 — Accepted ※ 15 August 2022 — Issue date ※ 25 August 2022

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TUPA37

A Distributed Beam Loss Monitor Based upon Activation of Oxygen in Deionised Cooling Water

storage-ring, detector, photon, experiment

433

K.P. Wootton
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.
We propose a novel beam loss detection scheme whereby activation of deionised cooling water is used to observe elevated radiation around the APS storage ring. This is based on radioactivation of oxygen within deionised cooling water by gamma rays above 10 MeV and neutrons above 15 MeV. Losses would be detected using a gamma ray detector monitoring process water flow out of the accelerator enclosure. We anticipate that this could be used to provide a segmented, distributed loss monitor system covering the accelerator components closest to locations where radiation is generated.

Poster TUPA37 [0.528 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA37

About •

Received ※ 02 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 26 September 2022

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TUPA53

Modeling of Nonlinear Beam Dynamics via a Novel Particle-Mesh Method and Surrogate Models with Symplectic Neural Networks

simulation, network, electron, synchrotron-radiation

462

C.-K. Huang, O. Beznosov, J.W. Burby, B.E. Carlsten, G.A. Dilts, J. Domine, R. Garimella, A. Kim, T.J. Kwan, H.N. Rakotoarivelo, R.W. Robey, B. Shen, Q. Tang
LANL, Los Alamos, New Mexico, USA
F.Y. Li
New Mexico Consortium, Los Alamos, USA

Funding: Work supported by the LDRD program at Los Alamos National Laboratory and the ASCR SciML program of DOE.
The self-consistent nonlinear dynamics of a relativistic charged particle beam, particularly through the interaction with its complete self-fields, is a fundamental problem underpinning many accelerator design issues in high brightness beam applications, as well as the development of advanced accelerators. A novel self-consistent particle-mesh code, CoSyR [1], is developed based on a Lagrangian method for the calculation of the beam particles’ radiation near-fields and associated beam dynamics. Our recent simulations reveal the slice emittance growth in a bend and complex interplay between the longitudinal and transverse dynamics that are not captured in the 1D longitudinal static-state Coherent Synchrotron Radiation (CSR) model. We further show that surrogate models with symplectic neural networks can be trained from simulation data with significant time-savings for the modeling of nonlinear beam dynamics effects. Possibility to extend such surrogate models for the study of spin-orbital coupling is also briefly discussed.
[1] C.-K. Huang et al., Nucl. Instruments Methods Phys. Res. Sect. A, vol. 1034, p. 166808, 2022.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA53

About •

Received ※ 25 July 2022 — Revised ※ 03 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 11 August 2022

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TUPA72

Comparison Study on First Bunch Compressor Schemes by Conventional and Double C-Chicane for MaRIE XFEL

dipole, emittance, electron, FEL

496

H. Xu, P.M. Anisimov, L.D. Duffy, Q.R. Marksteiner
LANL, Los Alamos, New Mexico, USA

Funding: Laboratory Directed Research and Development program of Los Alamos National Laboratory, project number 20200287ER.
We report our comparison study on the first stage electron bunch compression schemes at 750 MeV using a conventional and a double C-chicane for the X-ray free electron laser (XFEL) under development for the Matter-Radiation Interactions in Extremes (MaRIE) initiative at Los Alamos National Laboratory. Compared to the performance of the conventional C-chicane bunch compressor, the double C-chicane scheme exhibits the capability of utilizing the transverse momentum shift induced by the coherent synchrotron radiation in the second C-chicane to compensate that generated in the first C-chicane, resulting in a compressed electron bunch with minimized transverse momentum shift along the beam. It is also found that the double C-chicane scheme can be designed to significantly better preserve the beam emittance in the course of the bunch compression. This is particularly beneficial for the MaRIE XFEL whose lasing performance critically depends on the preservation of the ultralow beam emittance.

Poster TUPA72 [1.339 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA72

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Received ※ 01 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 15 August 2022

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TUPA74

Numerical Calculations of Wave Generation from a Bunched Electron Beam in Space

electron, plasma, simulation, experiment

502

H. Xu, G.L. Delzanno, L.D. Duffy, Q.R. Marksteiner, G.D. Reeves
LANL, Los Alamos, New Mexico, USA

Funding: This project was supported by the Laboratory Directed Research and Development program of Los Alamos National Laboratory.
We present our numerical approach and preliminary results of the calculations of whistler and X-mode wave generation by a bunched electron beam in space. The artificial generation of whistler and X-mode plasma waves in space is among the candidate techniques to accomplish the radiation belt remediation (RBR), in an effort to precipitate energetic electrons towards the atmosphere to reduce their threat to low-Earth orbit satellites. Free-space propagation of an electron pulse in a constant background magnetic field was simulated with the CST particle-in-cell (PIC) solver, with the temporal evolution of the beam recorded. The SpectralPlasmaSolver (SPS) was then modified to use the recorded electron pulse propagation to calculate the real-time plasma waves generated by the beam. SPS simulation results of the wave generation for the upcoming Beam-PIE experiment as well as an ideal bunched electron beam are shown.

Poster TUPA74 [0.963 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA74

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Received ※ 18 July 2022 — Revised ※ 02 August 2022 — Accepted ※ 07 August 2022 — Issue date ※ 08 August 2022

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TUPA84

Reconstructing Beam Parameters from Betatron Radiation Through Machine Learning and Maximum Likelihood Estimation

betatron, simulation, diagnostics, plasma

527

S. Zhang, N. Majernik, B. Naranjo, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, California, USA
Ö. Apsimon, C.P. Welsch, M. Yadav
The University of Liverpool, Liverpool, United Kingdom

Funding: US Department of Energy, Division of High Energy Physics, under Contract No. DE-SC0009914.
The dense drive beam used in plasma wakefield acceleration generates a linear focusing force that causes electrons inside the witness beam to undergo betatron oscillations, giving rise to betatron radiation. Because information about the properties of the beam is encoded in the betatron radiation, measurements of the radiation such as those recorded by the UCLA-built Compton spectrometer can be used to reconstruct beam parameters. Two possible methods of extracting information about beam parameters from measurements of radiation are machine learning (ML), which is increasingly being implemented for different fields of beam diagnostics, and a statistical technique known as maximum likelihood estimation (MLE). We assess the ability of both machine learning and MLE methods to accurately extract beam parameters from measurements of betatron radiation.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA84

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Received ※ 02 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 05 October 2022

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TUPA87

Simulations for the Space Plasma Experiments at the SAMURAI Lab

electron, plasma, simulation, experiment

539

P. Manwani, H.S. Ancelin, A. Fukasawa, G.E. Lawler, N. Majernik, B. Naranjo, J.B. Rosenzweig, Y. Sakai, O. Williams
UCLA, Los Angeles, California, USA
G. Andonian
RadiaBeam, Santa Monica, California, USA

Funding: This work was performed with support of the US Department of Energy under Contract No. DE-SC0017648 and DESC0009914, and the DARPA GRIT Contract 20204571
Plasma wakefield acceleration using the electron linear accelerator test facility, SAMURAI, can be used to study the Jovian electron spectrum due to the high energy spread of the beam after the plasma interaction. The SAMURAI RF facility which is currently being constructed and commissioned at UCLA, is is capable of producing beams with 10 MeV energy, 2 nC charge, and 200 fsec bunch lengths with a 4 um emittance. Particle-in-cell (PIC) simulations are used to study the beam spectrum that would be generated from plasma interaction. Experimental methods and diagnostics are discussed in this paper.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA87

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Received ※ 04 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 06 September 2022

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WEXD3

Map Tracking Including the Effect of Stochastic Radiation

emittance, lattice, damping, photon

548

D. Sagan, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
E. Forest
KEK, Ibaraki, Japan

Funding: Department of Energy
Using transfer maps to simulate charged particle motion in accelerators is advantageous since it is much faster than tracking step-by-step. One challenge to using transfer maps is to properly include radiation effects. The effect of radiation can be divided into deterministic and stochastic parts. While computation of the deterministic effect has been previously reported, handling of the stochastic part has not. In this paper, an algorithm for including the stochastic effect is presented including taking into account the finite opening angle of the emitted photons. A comparison demonstrates the utility of this approach. Generating maps which include radiation has been implemented in the PTC software library which is interfaced to the Bmad toolkit.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD3

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Received ※ 06 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 24 August 2022

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WEPA04

Simulating Two Dimensional Transient Coherent Synchrotron Radiation in Julia

synchrotron-radiation, GPU, synchrotron, emittance

627

W. Lou, Y. Cai, C.E. Mayes
SLAC, Menlo Park, California, USA

Coherent Synchrotron Radiation (CSR) in bending magnets poses a limit for electron beams to reach high brightness in novel accelerators. While the longitudinal wakefield has been well studied in the one-dimensional CSR theory and implemented in various simulation codes, transverse wakefields have received less attention. Following the recently developed two and three-dimensional CSR theory, we developed software packages in Python and Julia to simulate the 2D CSR effects. The Python packages, PyCSR2D and PyCSR3D, utilize parallel processing in CPU to compute the steady-state CSR wakes. The Julia package, CSR2D.jl, additionally computes the 2D transient CSR wakes with GPU compatibility. We applied these codes to simulate the 2D CSR effects in the LCLS-II and FACET-II particle accelerators at the SLAC National Accelerator Laboratory.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA04

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Received ※ 03 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 18 August 2022

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WEPA08

Design and Operation Experience of a Multi-Collimator/YAG Screen Device on LCLS II Low Energy Beamline

wakefield, simulation, electron, gun

631

X. Liu, C. Adolphsen, M. Santana-Leitner, L. Xiao, F. Zhou
SLAC, Menlo Park, California, USA

During the commissioning of the normal conducting VHF RF gun of LCLS II, it was observed that field emission (dark current) of roughly 2 µA level was present under normal operation of the gun. While the dark current of this level is deemed manageable with existing beamline configurations, it is desired in precaution to add a collimator on the low energy beamline to block the dark current, being concerned that the dark current situation might worsen with time. Since no spare longitudinal space is available, the new device takes place of the existing YAG screen. The new device is made of a 15 mm thick copper plate, with four round apertures of 6, 8, 10, and 12 mm radius respectively. At the end of the collimator plate, features are made for clamping two YAG screens and mounting their corresponding mirrors for beam/halo profile imaging. The collimator plate is electrically insulated from the chamber so that it can also be used for measuring the dark current. A motor-driven UHV compatible linear translator shifts the device between positions. Besides design details, related thermal, beam dynamics, and radiation analyses as well as operation experience will be presented.

* Work supported by US DOE under contract AC02-76SF00515.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA08

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Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 13 September 2022

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WEPA25

Field Emission Mitigation in CEBAF SRF Cavities Using Deep Learning

cavity, detector, neutron, linac

676

K. Ahammed, J. Li
ODU, Norfolk, Virginia, USA
A. Carpenter, R. Suleiman, C. Tennant, L.S. Vidyaratne
JLab, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
The Continuous Electron Beam Accelerator Facility (CEBAF) operates hundreds of superconducting radio frequency (SRF) cavities in its two main linear accelerators. Field emission can occur when the cavities are set to high operating RF gradients and is an ongoing operational challenge. This is especially true in newer, higher gradient SRF cavities. Field emission results in damage to accelerator hardware, generates high levels of neutron and gamma radiation, and has deleterious effects on CEBAF operations. So, field emission reduction is imperative for the reliable, high gradient operation of CEBAF that is required by experimenters. Here we explore the use of deep learning architectures via multilayer perceptron to simultaneously model radiation measurements at multiple detectors in response to arbitrary gradient distributions. These models are trained on collected data and could be used to minimize the radiation production through gradient redistribution. This work builds on previous efforts in developing machine learning (ML) models, and is able to produce similar model performance as our previous ML model without requiring knowledge of the field emission onset for each cavity.

Poster WEPA25 [1.586 MB]

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reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA25

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Received ※ 01 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 05 August 2022 — Issue date ※ 20 September 2022

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WEPA44

Compact Inter-Undulator Diagnostic Assembly for TESSA-515

undulator, quadrupole, electron, diagnostics

732

T.J. Hodgetts, R.B. Agustsson, Y.C. Chen, A.Y. Murokh, M. Ruelas
RadiaBeam, Santa Monica, California, USA
P.E. Denham, A.C. Fisher, J. Jin, P. Musumeci, Y. Park
UCLA, Los Angeles, USA

Funding: DOE grant DE-SC0009914, DE-SC0018559, and DE-SC0017102.
Beamline space is a very expensive and highly sought-after commodity, which makes the creation of compact integrated optics and diagnostics extremely valuable. The FAST- GREENS experimental program aims at demonstrating 10 % extraction efficiency from a relativistic electron beam using four helical undulators operating in the high gain TESSA regime. The inter-undulator gap needs to be as short as possible (17 cm in the current plans) to maximize the output power. Within this short distance, we needed to fit two focusing quadrupoles, a variable strength phase shifter, a transverse profile monitor consisting of a YAG-OTR combination for co-aligning the electron beam and laser, and an ion pump. By making the quadrupoles tunable with a variable gradient, in combination with vertical displacement, we can meet the optics requirements of matching the beam transversely to the natural focusing of the undulators. The two quadrupoles in conjunction with the electromagnetic dipole also serve as a phase shifter to realign the radiation and the bunching before each undulator section. This paper will discuss the mechanical design of this inter-undulator break section and its components.

Poster WEPA44 [0.752 MB]

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reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA44

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Received ※ 27 July 2022 — Revised ※ 03 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 11 August 2022

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WEPA73

Numerical Studies of Geometric Impedance at NSLS-II with GdfidL and ECHO3D

impedance, simulation, vacuum, wakefield

802

A. Khan, M. Seegitz, V.V. Smaluk, R.J. Todd
BNL, Upton, New York, USA
A. Blednykh
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA

The beam intensity in future low-emittance light sources with small gap wigglers and undulators is limited by the effects of short-range wakefields, especially by the beam-induced heating of the vacuum chamber components. We have cross-checked two electromagnetic solvers, GdfidL and ECHO3D, by simulation of the short-range wakefields in the NSLS-II flange absorber and in the taper transition of an in-vacuum undulator to test the consistency and precision of the wakefield models.

Poster WEPA73 [1.057 MB]

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reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA73

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Received ※ 01 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 01 September 2022

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THYD6

Arrival Time and Energy Jitter Effects on the Performance of X-Ray Free Electron Laser Oscillator

FEL, cavity, electron, laser

866

G. Tiwari
BNL, Upton, New York, USA
K.-J. Kim, R.R. Lindberg
ANL, Lemont, Illinois, USA
K.-J. Kim
University of Chicago, Chicago, Illinois, USA

Funding: U.S. Dept. of Energy Office of Sciences under Contract No. DE-AC02-06CH11357.
We report on the effects of electron beam arrival time and energy jitter on the power level and the fluctuations of the output of an X-ray FEL oscillator (XFELO). For this study, we apply the FEL driven paraxial resonator model of XFELO along with an analytical reflectivity profile to mimic the phase shift and spectral filtering effects of Bragg-crystals. The thresholds for acceptable timing jitters and energy jitters are determined in terms of the fluctuations of the steady-state power output. We explore potential ways to mitigate the power output fluctuations in the presence of unavoidable electron beam jitters.

Slides THYD6 [1.935 MB]

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reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-THYD6

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Received ※ 01 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 03 October 2022

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THYE4

Development of an Ultra-Low Vibration Cryostat Based on a Closed-Cycle Cryocooler

vacuum, cryogenics, instrumentation, synchrotron

874

R.W. Roca
Illinois Institute of Technology, Chicago, Illinois, USA
E.W. Knight, R.A. Kostin, Y. Zhao
Euclid TechLabs, Solon, Ohio, USA

Low temperature and low vibration cryostats are useful in a variety of applications such as x-ray diffraction, quantum computing, x-ray monochromators and cryo-TEMs. In this project, we explore an ultra-low vibration cryostat with the cooling provided by a closed cycle cryocooler. Closed-cycle cryocoolers inevitably introduce vibrations into the system, and in this project, flexible copper braiding was used to decouple vibrations and provide cooling at the same time. In order to develop the cryostat, capacity map of a two stage Sumitomo cryocooler was measured as well as vibration transmission through different copper braids using an IR interferometer. This paper covers the capacity map and vibration measurements in the first prototype.

Slides THYE4 [4.989 MB]

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reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-THYE4

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Received ※ 16 July 2022 — Revised ※ 10 August 2022 — Accepted ※ 20 August 2022 — Issue date ※ 12 September 2022

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