Keyword: 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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)