Keyword: solenoid
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MOZD4 Uncertainty Quantification of Beam Parameters in a Linear Induction Accelerator Inferred from Bayesian Analysis of Solenoid Scans experiment, electron, induction, space-charge 34
  • M.A. Jaworski, D.C. Moir, S. Szustkowski
    LANL, Los Alamos, New Mexico, USA
  Linear induction accelerators (LIAs) such as the DARHT at Los Alamos National Laboratory make use of the beam envelope equation to simulate the beam and design experiments. Accepted practice is to infer beam parameters using the solenoid scan technique with optical transition radiation (OTR) beam profiles. These scans are then analyzed with an envelope equation solver to find a solution consistent with the data and machine parameters (beam energy, current, magnetic field, and geometry). The most common code for this purpose with flash-radiography LIAs is xtr [1]. The code assumes the machine parameters are perfectly known and that beam profiles will follow a normal distribution about the best fit and solves by minimizing a chi-square-like metric. We construct a Bayesian model of the beam parameters allowing maching parameters, such as solenoid position, to vary within reasonable uncertainty bounds. Posterior distribution functions are constructed using Markov-Chain Monte Carlo (MCMC) methods to evaluate the accuracy of the xtr solution uncertainties and the impact of finite precision in measurements.
[1] P.W. Allison, "Beam dynamics equations for xtr," Los Alamos Technical Report LA-UR-01-6585. November 2001.
slides icon Slides MOZD4 [1.082 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOZD4  
About • Received ※ 05 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 20 August 2022
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MOPA08 Beamline Optimization Methods for High Intensity Muon Beams at PSI dipole, experiment, target, quadrupole 63
  • E.V. Valetov
    PSI, Villigen PSI, Switzerland
  Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 884104 (PSI-FELLOW-III-3i).
We perform beamline design optimization for the High Intensity Muon Beams (HIMB) project at the Paul Scherrer Institute (PSI), which will deliver muon beams at the unprecedented rate of 1·1010 muons/s to next-generation intensity frontier particle physics and material science experiments. For optimization of the design and operational parameters to maximize the beamline transmission, we use the asynchronous Bayesian optimization package DeepHyper and a custom build of G4beamline with variance reduction and measured cross sections. We minimize the beam spot size at the final foci using a COSY INFINITY model with differential-algebraic system knobs, where we minimize the respective transfer map elements using the Levenberg-Marquardt and simulated annealing optimizers. We obtained a transmission of 1.34·1010 muons/s in a G4beamline model of HIMB’s MUH2 beamline into the experimental area.
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA08  
About • Received ※ 02 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 23 August 2022
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MOPA17 Symplectic Particle Tracking in a Thick Nonlinear McMillan Lens for the Fermilab Integrable Optics Test Accelerator (IOTA) electron, optics, simulation, lattice 83
  • B.L. Cathey, G. Stancari, T. Zolkin
    Fermilab, Batavia, Illinois, USA
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The McMillan system is a novel method to increase the tune spread of a beam without decreasing its dynamic aperture due to the system’s integrability. While the ideal system is based on an infinitely thin kick, the physical design requires a thick electron lens, including a solenoid. Particle transport through the lens is difficult to simulate due to the nature of the force on the circulating beam. This paper demonstrates accurate simulation of a thick McMillan lens in a solenoid using symplectic integrators derived from Yoshida’s method.
poster icon Poster MOPA17 [2.290 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA17  
About • Received ※ 03 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 09 October 2022
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MOPA36 Optimization of Superconducting Linac for Proton Improvement Plan-II (PIP-II) emittance, linac, cavity, quadrupole 132
  • A. Pathak, E. Pozdeyev
    Fermilab, Batavia, Illinois, USA
  PIP-II is an essential upgrade of the Fermilab complex that will enable the world’s most intense high-energy beam of neutrinos for the international Deep Underground Neutrino Experiment at LBNF and support a broad physics program at Fermilab. Ultimately, the PIP-II superconducting linac will be capable of accelerating the H CW beam to 800 MeV with an average power of 1.6 MW. To operate the linac with such high power, beam losses and beam emittance growth must be tightly controlled. In this paper, we present the results of global optimization of the Linac options towards a robust and efficient physics design for the superconducting section of the PIP-II linac. We also investigate the impact of the nonlinear field of the dipole correctors on the beam quality and derive the requirement on the field quality using statistical analysis. Finally, we assess the need to correct the quadrupole focusing produced by Half Wave, and Single Spoke accelerating cavities. We assess the feasibility of controlling the beam coupling in the machine by changing the polarity of the field of Linac focusing solenoids  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA36  
About • Received ※ 02 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 01 October 2022
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MOPA69 Adjoint Optimization Applied to Flat to Round Transformers quadrupole, lattice, space-charge, electron 199
  • T.M. Antonsen, B.L. Beaudoin, S. Bernal, L. Dovlatyan, I. Haber, P.G. O’Shea, D.F. Sutter
    UMD, College Park, Maryland, USA
  Funding: This work was supported by DOE-HEP Awards No. DESC0010301 and DESC0022009
We present the numerical optimization, using adjoint techniques, of Flat-to-Round (FTR) transformers operating in the strong self-field limit. FTRs transform an unmagnetized beam that has a high aspect ratio, elliptical spatial cross section, to a round beam in a solenoidal magnetic field. In its simplest form the flat to round conversion is accomplished with a triplet of quadrupoles, and a solenoid. FTR transformers have multiple applications in beam physics research, including manipulating electron beams to cool co-propagating hadron beams. Parameters that can be varied to optimize the FTR conversion are the positions and strengths of the four magnet elements, including the orientations and axial profiles of the quadrupoles and the axial profile and strength of the solenoid’s magnetic field. The adjoint method we employ [1] allows for optimization of the lattice with a minimum computational effort including self-fields. The present model is based on a moment description of the beam. However, the generalization to a particle description will be presented. The optimized designs presented here will be tested in experiments under construction at the University of Maryland.
[1] Optimization of Flat to Round Transformers with self-fields using adjoint techniques, L. Dovlatyan, B. Beaudoin, S. Bernal, I. Haber, D. Sutter and TMA, PhysRevAccelBeams.25.044002 (2022).
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA69  
About • Received ※ 03 August 2022 — Revised ※ 25 September 2022 — Accepted ※ 05 December 2022 — Issue date ※ 05 December 2022
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MOPA83 Automation of Superconducting Cavity and Superconducting Magnet Operation for FRIB cavity, operation, linac, cryomodule 239
  • W. Chang, Y. Choi, X.-J. Du, W. Hartung, S.H. Kim, T. Konomi, S.R. Kunjir, H. Nguyen, J.T. Popielarski, K. Saito, T. Xu, S. Zhao
    FRIB, East Lansing, Michigan, USA
  The superconducting (SC) driver linac for the Facility for Rare Isotope Beams (FRIB) is a heavy-ion accelerator that accelerate ions to 200 MeV per nucleon. The linac has 46 cryomodules that contain 324 SC cavities and 69 SC solenoid packages. For linac operation with high availability and high reliability, automation is essential for such tasks as fast device turn-on/off, fast recovery from trips, and real-time monitoring of operational performance. We have implemented several automation algorithms, including one-button turn-on/off of SC cavities and SC magnets; automated degaussing of SC solenoids; mitigation of field emission-induced multipacting during recovery from cavity trips; and real-time monitoring of the cavity field level calibration. The design, development, and operating experience with automation will be presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA83  
About • Received ※ 02 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 26 August 2022
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TUZE5 Studies of Ion Beam Heating by Electron Beams electron, emittance, experiment, gun 343
  • S. Seletskiy, A.V. Fedotov, D. Kayran
    BNL, Upton, New York, USA
  Presence of an electron beam created by either electron coolers or electron lenses in an ion storage ring is associated with an unwanted emittance growth (heating) of the ion bunches. In this paper we report experimental studies of the electron-ion heating in the Low Energy RHIC electron Cooler (LEReC).  
slides icon Slides TUZE5 [1.368 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUZE5  
About • Received ※ 01 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 17 September 2022
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TUPA14 Fast First-Order Spin Propagation for Spin Matching and Polarization Optimization with Bmad polarization, quadrupole, lattice, electron 369
  • J.M. Asimow, G.H. Hoffstaetter, D. Sagan, M.G. Signorelli
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  Accurate spin tracking is essential for the simulation and propagation of polarized beams, in which a majority of the particles’ spin point in the same direction. Bmad, an open-sourced library for the simulation of charged particle dynamics, traditionally tracks spin via integrating through each element of a lattice. While exceptionally accurate, this method has the drawback of being slow; at best, the runtime is proportional to the length of the element. By solving the spin transport equation for simple magnet elements, Bmad can reduce this algorithm to constant runtime while maintaining high accuracy. This method, known as "Sprint," enables quicker spin matching and prototyping of lattice designs via Bmad.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA14  
About • Received ※ 30 July 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 24 August 2022
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WEXD5 Benchmarking Simulation for AWA Drive Linac and Emittance Exchange Beamline Using OPAL, GPT, and Impact-T simulation, emittance, linac, gun 552
  • S.Y. Kim, G. Chen, D.S. Doran, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • E.A. Frame, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  At the Argonne Wakefield Accelerator (AWA) facility, particle-tracking simulations have been critical to guiding beam-dynamic experiments, e.g., for various beam manipulations using an available emittance-exchange beamline (EEX). The unique beamline available at AWA provide a test case to perform in-depth comparison between different particle-tracking programs including collective effects such as space-charge force and coherent synchrotron radiation. In this study, using AWA electron injector and emittance exchange beamline, we compare the simulations results obtained by GPT, OPAL, and Impact-T beam-dynamics programs. We will specifically report on convergence test as a function of parameters that controls the underlying algorithms.  
slides icon Slides WEXD5 [1.847 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD5  
About • Received ※ 03 August 2022 — Revised ※ 06 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 22 August 2022
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WEYD6 Design of a PIP-II Era Mu2e Experiment proton, target, experiment, collider 568
  • M.A. Cummings, R.J. Abrams, R.P. Johnson, T.J. Roberts
    Muons, Inc, Illinois, USA
  • D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  We propose a design of an upgraded Mu2e experiment for the future Fermilab PIP-II era based on the muon collider front end. The consensus is that such an upgrade should provide a factor of 10 increase in the rate of stopping muons in the experimental target. The current Mu2e design is optimized for 8 kW of protons at 8 GeV. The PIP-II upgrade project is a 250-meter-long CW linac capable of accelerating a 2-mA proton beam to a kinetic energy of 800 MeV (total power 1.6 MW). This would significantly improve the Fermilab proton source to enable next-generation intensity frontier experiments. But using this 800 MeV beam poses challenges to the Mu2E experiment. Bright muon beams generated from sources designed for muon collider and neutrino factory facilities have been shown to generate two orders of magnitude more muons per proton than the current Mu2e production target and solenoid. In contrast to the current Mu2e, the muon collider design has forward-production of muons from the target.  
slides icon Slides WEYD6 [1.937 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEYD6  
About • Received ※ 06 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 09 October 2022
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WEPA02 Beam Dynamics Studies on a Low Emittance Injector for LCLS-II-HE emittance, cathode, gun, cavity 619
  • F. Ji, C. Adolphsen, R. Coy, L. Ge, C.E. Mayes, T.O. Raubenheimer, L. Xiao
    SLAC, Menlo Park, California, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  The SLAC High Energy upgrade of LCLS-II (LCLS-II-HE) will double the beam energy to 8 GeV, increasing the XFEL photon energy reach to about 13 keV. The energy reach can be extended to 20 keV if the beam emittance can be halved, which requires a higher gradient electron gun with a lower intrinsic emittance photocathode. To this end, the Low Emittance Injector (LEI) will be built that will run parallel to the existing LCLS-II Injector. The LEI design will be based on a state-of-the-art SRF gun with a 30 MV/m cathode gradient. The main goal is to produce transverse beam emittances of 0.1 mm-mrad for 100 pC bunch charges. This paper describes the beam dynamics studies on the design of the LEI including the simulations and multi-objective genetic algorithm (MOGA) optimizations. Performance with different injector layouts, cathode gradients, bunch charges and cathode mean transverse energies (MTEs) will be presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA02  
About • Received ※ 02 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 17 August 2022
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THXD2 6D Phase Space Diagnostics Based on Adaptive Tuning of the Latent Space of Encoder-Decoder Convolutional Neural Networks controls, feedback, network, electron 837
  • A. Scheinker
    LANL, Los Alamos, New Mexico, USA
  We present a general approach to 6D phase space diagnostics for charged particle beams based on adaptively tuning the low-dimensional latent space of generative encoder-decoder convolutional neural networks (CNN). Our approach first trains the CNN based on supervised learning to learn the correlations and physics constrains within a given accelerator system. The input of the CNN is a high dimensional collection of 2D phase space projections of the beam at the accelerator entrance together with a vector of accelerator parameters such as magnet and RF settings. The inputs are squeezed down to a low-dimensional latent space from which we generate the output in the form of projections of the beam’s 6D phase space at various accelerator locations. After training the CNN is applied in an unsupervised adaptive manner by comparing a subset of the output predictions to available measurements with the error guiding feedback directly in the low-dimensional latent space. We show that our approach is robust to unseen time-variation of the input beam and accelerator parameters and a study of the robustness of the method to go beyond the span of the training data.  
slides icon Slides THXD2 [19.086 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-THXD2  
About • Received ※ 18 July 2022 — Revised ※ 05 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 09 August 2022
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