05: Beam Dynamics
Paper Title Page
MOPA17 Symplectic Particle Tracking in a Thick Nonlinear McMillan Lens for the Fermilab Integrable Optics Test Accelerator (IOTA) 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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MOPA33 Waker Experiments at Fermilab Recycler Ring 124
 
  • O. Mohsen, R. Ainsworth, N. Eddy
    Fermilab, Batavia, Illinois, USA
  
  Attaining high-intensity hadron beams is often limited due to the transverse collective instabilities, whose understanding is thus required to see and possibly extend the intensity limitations. To explore such instabilities, a novel artificial wake system, the waker, has been built and tested at the Fermilab Recycler Ring (RR). In this report, we show recent upgrades of the waker. Also, we present experimental studies of instabilities at various space charge and wake parameters.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA33  
About • Received ※ 03 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 28 August 2022
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MOPA36 Optimization of Superconducting Linac for Proton Improvement Plan-II (PIP-II) 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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MOPA60 HFSS Enables Multipaction Analysis of High Power RF/Microwave Components 176
 
  • S.A. Ahmed
    Ansys, Inc., Canonsburg, USA
  
  The radiofrequency (RF) components in particle accelerators operated under a vacuum and driven by high RF power may be prone to electron multipaction ’ an RF triggered electron resonance phenomenon causing malfunction or complete breakdown. Therefore, exploring the design challenges of vacuum RF windows, cavities, and other devices for the electron multipaction becomes necessary. Setting up an experiment to mitigate the failure of RF devices is expensive and time-consuming, which may cause a significant delay in the project. Therefore, a high-fidelity computer simulation modeling the arbitrary geometry and tracking the particles (electrons) in a complex electromagnetic environment is desirable. Ansys HFSS through Finite Element Mesh (FEM) for the full-wave RF simulation combined with the particle-in-cell (PIC) technique for tracking particles in EM fields; enables the engineers/physicist successful prediction of system failure against the electron multipaction. This paper will demonstrate the workflow of the HFSS multipaction analysis.
The author like to thank Robert Chao for the valuable discussions and his efforts in developing this capability in the Ansys Electronics Desktop. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA60  
About • Received ※ 03 August 2022 — Revised ※ 13 August 2022 — Accepted ※ 26 August 2022 — Issue date ※ 06 October 2022
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MOPA64 Circular Modes for Mitigating Space-Charge Effects and Enabling Flat Beams 189
 
  • O. Gilanliogullari
    IIT, Chicago, Illinois, USA
  • B. Mustapha
    ANL, Lemont, Illinois, USA
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illlinois, USA
  
  Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC02-06CH11357
Flat beams are preferred in high-intensity accelerators and high-energy colliders due to one of the transverse plane emittances being smaller, which enhances luminosity and beam brightness. However, flat beams are devastating at low energies due to space charge forces which are significantly enhanced in one plane. The same is true, although to a lesser degree, for non-symmetric elliptical beams. In order to mitigate this effect, circular mode beam optics can be used. In this paper, we show that circular mode beams dilute space charge effects at lower energies, and can be transformed to flat beams later on. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA64  
About • Received ※ 09 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 23 August 2022
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MOPA69 Adjoint Optimization Applied to Flat to Round Transformers 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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MOPA72 Preliminary Tests and Beam Dynamics Simulations of a Straight-Merger Beamline 206
 
  • A.A. Al Marzouk, P. Piot, T. Xu
    Northern Illinois University, DeKalb, Illinois, USA
  • S.V. Benson, K.E. Deitrick, J. Guo, A. Hutton, G.-T. Park, S. Wang
    JLab, Newport News, Virginia, USA
  • D.S. Doran, G. Ha, P. Piot, J.G. Power, C. Whiteford, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • C.E. Mitchell, J. Qiang, R.D. Ryne
    LBNL, Berkeley, California, USA
  
  Funding: NSF award PHY-1549132 to Cornell University and NIU, U.S. DOE contract DE-AC02-06CH11357 with ANL and DE-AC05-06OR23177 with JLAB.
Beamlines capable of merging beams with different energies are critical to many applications related to advanced accelerator concepts and energy-recovery linacs (ERLs). In an ERL, a low-energy "fresh" bright bunch is generally injected into a superconducting linac for acceleration using the fields established by a decelerated "spent" beam traveling on the same axis. A straight-merger system composed of a selecting cavity with a superimposed dipole magnet was proposed and recently test at AWA. This paper reports on the experimental results obtained so far along with detailed beam dynamics investigations of the merger concept and its ability to conserve the beam brightness associated with the fresh bunch. 		 
poster icon Poster MOPA72 [1.659 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA72  
About • Received ※ 11 August 2022 — Accepted ※ 13 August 2022 — Issue date ※ 02 October 2022  
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MOPA78 Temporally-Shaped Ultraviolet Pulses for Tailored Bunch Generation at Argonne Wakefield Accelerator 222
 
  • T. Xu, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • S. Carbajo
    UCLA, Los Angeles, California, USA
  • S. Carbajo, R.A. Lemons
    SLAC, Menlo Park, California, USA
  • P. Piot
    ANL, Lemont, Illinois, USA
  
  Photocathode laser shaping is an appealing technique to generate tailored electron bunches due to its versatility and simplicity. Most photocathodes require photon energies exceeding the nominal photon energy produced by the lasing medium. A common setup consists of an infrared (IR) laser system with nonlinear frequency conversion to the ultraviolet (UV). In this work, we present the numerical modeling of a temporal shaping technique capable of producing electron bunches with linearly-ramped current profiles for application to collinear wakefield accelerators. Specifically, we show that controlling higher-order dispersion terms associated with the IR pulse provides some control over the UV temporal shape. Beam dynamics simulation of an electron-bunch shaping experiment at the Argonne Wakefield Accelerator is presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA78  
About • Received ※ 01 August 2022 — Revised ※ 06 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 31 August 2022
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MOPA81 Study of Nonlinear Dynamics in the 4-D Hénon Map Using the Square Matrix Method and Iterative Methods 232
 
  • K.J. Anderson, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • L.H. Yu
    BNL, Upton, New York, USA
  
  Funding: Accelerator Stewardship program under award number DE-SC0019403 US Department of Energy, Office of Science, High Energy Physics under award number DE-SC0018362 and Michigan State University
The Hénon Map represents a linear lattice with a single sextupole kick. This map has been extensively studied due to its chaotic behavior. The case for the two dimensional phase space has recently been revisited using ideas from KAM theory to create an iterative process that transforms nonlinear perturbed trajectories into rigid rotations*. The convergence of this method relates to the resonance structure and can be used as an indicator of the dynamic aperture. The studies of this method have been extended to the four dimensional phase space case which introduces coupling between the transverse coordinates.
*Hao, Y., Anderson, K., & Yu, L. H. (2021, August). Revisit of Nonlinear Dynamics in Hénon Map Using Square Matrix Method. https://doi.org/10.18429/JACoW-IPAC2021-THPAB016 		 
poster icon Poster MOPA81 [3.103 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA81  
About • Received ※ 19 July 2022 — Revised ※ 04 August 2022 — Accepted ※ 15 August 2022 — Issue date ※ 26 August 2022
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MOPA82 Space Charge Driven Third Order Resonance at AGS Injection 236
 
  • M.A. Balcewicz, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • Y. Hao, H. Huang, C. Liu, K. Zeno
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
Resonance line crossings at significant space charge tune shifts can exhibit various phenomena due to periodic resonance crossing from synchrotron motion* and manifests as halo generation and bunch shortening along with the more mundane emittance growth and beam loss. An injection experiment is conducted at the AGS using the fast wall current monitor and electron collecting Ionization Profile Monitor (eIPM) to probe third order resonances to better characterize the resonance crossing over a 4 ms time scale. This experiment shows some agreement with previous experiments, save for lack of bunch shortening, possibly due to relative resonance strength.
* G. Franchetti et al. PRSTAB 13, 114203. 2010 		 
poster icon Poster MOPA82 [1.924 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA82  
About • Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 19 August 2022 — Issue date ※ 24 August 2022
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TUZE1 Experimental Phase-Space Tracking of a Single Electron in a Storage Ring 329
 
  • A.L. Romanov, J.K. Santucci, G. Stancari, A. Valishev
    Fermilab, Batavia, Illinois, USA
  
  This paper presents the results of the first ever experimental tracking of the betatron and synchrotron phases for a single electron in the Fermilab’s IOTA ring. The reported technology makes it is possible to fully track a single electron in a storage ring, which requires tracking of amplitudes and phases for both, slow synchrotron and fast betatron oscillations.  
slides icon Slides TUZE1 [3.600 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUZE1  
About • Received ※ 08 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 27 August 2022
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TUZE2
 Nonlinear Optics from Off-Energy Closed Orbits  
 
  • D.K. Olsson
    MAX IV Laboratory, Lund University, Lund, Sweden
  
  Among several techniques used to characterize and correct the non-linear optics of a storage ring, NOECO (Non-linear optics from Off-Energy Closed Orbits) is the natural expansion of the well-known scheme LOCO for quadrupoles. This approach is based on measuring an orbit response matrix at an off-nominal energy and it is valid for chromatic sextupoles. In this contribution the method [1] will be presented as deployed for the MAX IV 3 GeV ring.
[1] https://link.aps.org/doi/10.1103/PhysRevAccelBeams.23.102803
 		 
slides icon Slides TUZE2 [3.080 MB]  
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TUZE3 Optimizing the Discovery of Underlying Nonlinear Beam Dynamics 335
 
  • L.A. Pocher, T.M. Antonsen, L. Dovlatyan, I. Haber, P.G. O’Shea
    UMD, College Park, Maryland, USA
  
  Funding: Work supported by US DOE-HEP grants: DE-SC0010301 and DE-SC0022009
One of the DOE-HEP Grand Challenges identified by Nagaitsev et al. relates to the use of virtual particle accelerators for beam prediction and optimization. Useful virtual accelerators rely on efficient and effective methodologies grounded in theory, simulation, and experiment. This paper uses an algorithm called Sparse Identification of Nonlinear Dynamical systems (SINDy), which has not previously been applied to beam physics. We believe the SINDy methodology promises to simplify the optimization of accelerator design and commissioning, particularly where space charge is important. We show how SINDy can be used to discover and identify the underlying differential equation system governing the beam moment evolution. We compare discovered differential equations to theoretical predictions and results from the PIC code WARP modeling. We then integrate the discovered differential system forward in time and compare the results to data analyzed in prior work using a Machine Learning paradigm called Reservoir Computing. Finally, we propose extending our methodology, SINDy for Virtual Accelerators (SINDyVA), to the broader community’s computational and real experiments. 		 
slides icon Slides TUZE3 [3.141 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUZE3  
About • Received ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 22 August 2022  
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TUZE4 Particle-in-Cell Simulations of High Current Density Electron Beams in the Scorpius Linear Induction Accelerator 339
 
  • S.E. Clark, Y.-J. Chen, J. Ellsworth, A.T. Fetterman, C.N. Melton, W.D. Stem
    LLNL, Livermore, USA
  
  Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Particle-in-cell (PIC) simulations of a high current density (I > 1 kA), and highly relativistic electron beam (E ~ 2-20 MeV) in the Scorpius Linear Induction Accelerator (LIA) are presented. The simulation set consists of a 3D electrostatic/magnetostatic simulation coupled to a 2D XY slice solver that propagates the beam through the proposed accelerator lattice for Scorpius, a next-generation flash X-ray radiography source. These simulations focus on the growth of azimuthal modes in the beam (e.g. Diocotron instability) that arise when physical ring distributions manifest in the beam either due to electron optics or solenoidal focusing and transport. The saturation mechanism appears to lead to the generation of halo particles and conversion down to lower mode numbers as the width of the ring distribution increases. The mode growth and saturation can contribute to the generation of hot spots on the target as well possible azimuthal asymmetries in the radiograph. Simulation results are compared to linear theory and tuning parameters are investigated to mitigate the growth of azimuthal modes in the Scorpius electron beam.
* LLNL-ABS-830595, Approved for public release. Distribution Unlimited. 		 
slides icon Slides TUZE4 [4.305 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUZE4  
About • Received ※ 02 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 21 September 2022
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TUZE5 Studies of Ion Beam Heating by Electron Beams 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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TUZE6 Studies of Ion Instability Using a Gas Injection System 347
 
  • J.R. Calvey, M. Borland, L. Emery, P.S. Kallakuri
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Ion trapping occurs when a negatively charged beam ionizes residual gas inside an accelerator vacuum chamber, and the resulting ions become trapped in the beam potential. Trapped ions can cause a variety of undesirable effects, including coherent instability and incoherent emittance growth. Because of the challenging emittance and stability requirements of next generation light sources, ion trapping is a serious concern. To study this effect at the present APS, a gas injection system was designed and installed at two different locations in the ring. The system creates a controlled and localized pressure bump of nitrogen gas, so the resulting ion instability can be studied. Measurements were taken under a wide variety of beam conditions, using a spectrum analyzer, pinhole camera, and bunch-by-bunch feedback system. The feedback system was also used to perform grow-damp measurements, allowing us to measure the growth rate of individual unstable modes. This paper will present some of the results of these experiments. Simulations using the IONEFFECTS element in the particle tracking code elegant will also be presented. 		 
slides icon Slides TUZE6 [2.425 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUZE6  
About • Received ※ 03 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 24 August 2022
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TUPA16 Singularity-Free Exact Dipole Bend Transport Equations 375
 
  • D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: Department of Energy
Exact transport equations for a pure dipole bend (a bend with a dipole field and nothing else) have been derived and formulated to avoid singularities when evaluated. The transport equations include finite edge angles and no assumption is made in terms of the bending field being matched to the curvature of the coordinate system. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA16  
About • Received ※ 05 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 16 September 2022
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TUPA26 Fringe Field Maps for Cartesian Dipoles with Longitudinal and/or Transverse Gradients 401
 
  • R.R. Lindberg, M. Borland
    ANL, Lemont, Illinois, USA
  
  Funding: This work was supported by U.S. Dept. of Energy Office of Sciences under Contract No. DE-AC02-06CH11357.
Fringe fields effects in dipoles can give rise to important linear and nonlinear contributions. This paper describes how to extend the classic results of Brown [1] and the more recent calculations of Hwang and Lee [2] to Cartesian dipoles with transverse and/or longitudinal gradients. We do this by 1) introducing a more general definition of the fringe field that can be applied to longitudinal gradient dipoles, 2) allowing for quadrupole and/or sextupole content in the magnet body, and 3) showing how to employ the resulting fringe field maps as a symplectic transformation of the coordinates. We compare our calculation results with tracking for longitudinal and transverse gradient dipoles planned for the APS-U.
[1] K.L. Brown, Report SLAC-75, 1982.
[2] K. Hwang and S.Y. Lee, Phys. Rev. Accel. Beams, vol. 18, p. 122401 2015. 		 
poster icon Poster TUPA26 [2.090 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA26  
About • Received ※ 26 July 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 21 August 2022
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TUPA27 Longitudinal Feedback Dynamics in Storage Rings with Small Synchrotron Tunes 405
 
  • R.R. Lindberg
    ANL, Lemont, Illinois, USA
  
  Funding: This work was supported by U.S. Dept. of Energy Office of Sciences under Contract No. DE-AC02-06CH11357.
We analyze the dynamics of multibunch longitudinal instabilities including bunch-by-bunch feedback under the assumption that the synchrotron tune is small. We find that increasing the feedback response does not always guarantee stability, even in the ideal case with no noise. As an example, we show that if the growth rate of a cavity-driven mode is of the order of the synchrotron frequency, then there are parameter regions for which the instability cannot be controlled by feedback irrespective of its gain. We verify these calculations with tracking simulations relevant to the APS-U, and find that the dynamics do not depend upon whether the longitudinal feedback relies on phase-sensing or energy-sensing technology. Hence, this choice should be dictated by measurement accuracy and noise considerations. 		 
poster icon Poster TUPA27 [1.180 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA27  
About • Received ※ 26 July 2022 — Revised ※ 05 August 2022 — Accepted ※ 07 August 2022 — Issue date ※ 26 August 2022
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TUPA34 Model-Based Calibration of Control Parameters at the Argonne Wakefield Accelerator 427
 
  • I.P. Sugrue, B. Mustapha, P. Piot, J.G. Power
    ANL, Lemont, Illinois, USA
  • N. Krislock
    Northern Illinois University, DeKalb, Illinois, USA
  
  Particle accelerators utilize a large number of control parameters to generate and manipulate beams. Digital models and simulations are often used to find the best operating parameters to achieve a set of given beam parameters. Unfortunately, the optimized physics parameters cannot precisely be set in the control system due to, e.g., calibration uncertainties. We developed a data-driven physics-informed surrogate model using neural networks to replace digital models relying on beam-dynamics simulations. This surrogate model can then be used to perform quick diagnostics of the Argonne Wakefield accelerator in real time using nonlinear least-squares methods to find the most likely operating parameters given a measured beam distribution.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA34  
About • Received ※ 05 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 24 September 2022
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TUPA42 LANSCE Modernization Project at LANL 443
 
  • D.V. Gorelov, J. Barraza, D.A.D. Dimitrov, I. Draganić, E. Henestroza, S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
  
  In the framework of LANSCE Accelerator Modernization Project preliminary research, during evaluation of critical technology elements it was found that the proposed RFQ design had not yet been demonstrated experimentally worldwide. Such an RFQ should combine the ability of traditional light ion RFQs (i.e., [1]) and the flexibility of acceleration of pre-bunched beams, like RFQs for heavy ions [2]. The proposed RFQ should be able to accelerate H+ and H− beams with 35-mA beam current from 100 keV to 3 MeV and at the same time preserve the prescribed macro-bunch beam time structure required by experiments. New algorithms for RFQ geometry generation have been proposed, and optimization algorithms are being developed at LANL. LAMP demonstration plans also include development of a new set of electrodes for the existing RFQ at our Test Stand that will allow us to demonstrate the critical technology ahead of time in a laboratory experimental setup with low duty factor and low energy.
[1] S. Henderson et al., Nucl. Instrum. Methods Phys. Res., Sect. A, v. 763, pp. 610-673 (2014).
[2] H. Ren et al., J. Phys. Conf. Ser., v. 1067, 052010 (2018). 		 
poster icon Poster TUPA42 [0.635 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA42  
About • Received ※ 04 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 18 August 2022
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TUPA53 Modeling of Nonlinear Beam Dynamics via a Novel Particle-Mesh Method and Surrogate Models with Symplectic Neural Networks 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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TUPA56 Beam Coupling Impedances of Asymmetric Components of the Scorpius Induction Linac 469
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
  
  The transverse beam coupling impedance of induction linacs must be minimized to avoid beam breakdown instability. The vacuum chamber of the Scorpius linac contains complicated asymmetric elements. We present calculations of the transverse impedance for three asymmetric discontinuities: (1) a pumping section between accelerating cells, which contains vacuum plenum, pumping grid, and bellows; (2) a fast flapper valve; and (3) a debris blocker at the end of the linac. The dipole transverse impedance is calculated with CST Studio using both wakefield solver and eigen solver.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA56  
About • Received ※ 01 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 06 October 2022
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TUPA77 X-Band Harmonic Longitudinal Phase Space Linearization at the PEGASUS Photoinjector 508
 
  • P.E. Denham, P. Musumeci, A. Ody
    UCLA, Los Angeles, USA
  
  Due to the finite bunch length, photoemitted electron beams sample RF-nonlinearities that lead to energy-time correlations along the bunch temporal profile. This is an important effect for all applications where the projected energy spread is important. In particular, for time-resolved single shot electron microscopy, it is critical to keep the beam energy spread below 1·10-4 to avoid chromatic aberrations in the lenses. Higher harmonic RF cavities can be used to compensate for the RF-induced longitudinal phase space nonlinearities. Start-to-end simulations suggest that this type of compensation can reduce energy spread to the 1·10-5 level. This work is an experimental study of x-band harmonic linearization of a beam longitudinal phase space at the PEGASUS facility, including developing high-resolution spectrometer diagnostics to verify the scheme.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA77  
About • Received ※ 25 July 2022 — Revised ※ 04 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 10 August 2022
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TUPA82 Transverse Stability in an Alternating Symmetry Planar Dielectric Wakefield Structure 519
 
  • W.J. Lynn, G. Andonian, N. Majernik, S.M. OTool, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • D.S. Doran, S.Y. Kim, J.F. Power, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  
  Funding: DE-SC0017648 - AWA.
Dielectric Wakefield Acceleration (DWA) is a promising technique for realizing the next generation of linear colliders. It provides access to significantly higher accelerating gradients than traditional radio-frequency cavities. One impediment to realizing a DWA-powered accelerator is the issue of the transverse stability of the beams within the dielectric structure due to short-range wakefields. These short-range wakefields have a tendency to induce a phenomenon known as single-bunch beam breakup, which acts as its name implies and destroys the relevant beam. We attempt to solve this issue by leveraging the quadrupole mode excited in a planar dielectric structure and then alternating the orientation of said structure to turn an unstable system into a stable one. We examine this issue computationally to determine the limits of stability and based on those simulations describe a future experimental realization of this strategy. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA82  
About • Received ※ 02 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 30 September 2022
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WEXD1
 Advances in Beam Dynamics at Nuclear Physics Accelerator Facilities  
 
  • A.V. Sy
    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.
Beam dynamics of particle accelerators is a rich subfield that enables accelerators to be used in pursuit of fundamental topics in particle physics in increasingly complex ways. The field is constantly evolving as new and advanced accelerators push the limits of energy, luminosity, and accelerated species. This talk will cover some recent beam dynamics developments for future operation of DOE nuclear physics user facilities, including upgrade options for Jefferson Lab’s 12 GeV CEBAF. 		 
slides icon Slides WEXD1 [4.936 MB]  
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WEXD2 Storage Ring Tracking Using Generalized Gradient Representations of Full Magnetic Field Maps 542
 
  • R.R. Lindberg, M. Borland
    ANL, Lemont, Illinois, USA
  
  Funding: This work was supported by U.S. Dept. of Energy Office of Sciences under Contract No. DE-AC02-06CH11357.
We have developed a set of tools to simulate particle dynamics in the full magnetic field using the generalized gradients representation. Generalized gradients provide accurate and analytic representations of the magnetic field that allow for symplectic tracking [1]. We describe the tools that convert magnetic field data into generalized gradients representations suitable for tracking in Elegant, and discuss recent results based upon tracking with the full field representations for all magnets in the APS-U storage ring.
[1] A. Dragt. Lie Methods for Nonlinear Dynamics with Applications to Accelerator Physics. University of Maryland (2019). 		 
slides icon Slides WEXD2 [3.841 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD2  
About • Received ※ 16 July 2022 — Accepted ※ 29 July 2022 — Issue date ※ 04 August 2022  
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WEXD3 Map Tracking Including the Effect of Stochastic Radiation 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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WEXD4
 OPAL for Self-Consistent Start-to-End Simulation of Undulator-Based Facilities  
 
  • A. Albà, A. Adelmann
    PSI, Villigen PSI, Switzerland
  • A. Fallahi
    ETH Zurich, Photonics Laboratory, Zurich, Switzerland
  
  The Object Oriented Parallel Accelerator Library (OPAL), a parallel open source tool for charged-particle optics is augmented with a new flavor OPAL-FEL. With OPAL-FEL we solve the electromagnetic potential equations in free-space for radiating particles propagating along an undulator using an FDTD/PIC scheme. We present results of two benchmark [1] studies where OPAL-FEL simulations are compared to experimental results. Both experiments are about electron beamlines where the longitudinal phase space is modulated with a short magnetic wiggler. To our knowledge, this is the only beam dynamics model that allows a start-to-end simulation of FELs, in a fully 3D fashion including radiation.
[1] arXiv:2112.02316 (https://arxiv.org/pdf/2112.02316.pdf) 		 
slides icon Slides WEXD4 [7.843 MB]  
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WEXD5 Benchmarking Simulation for AWA Drive Linac and Emittance Exchange Beamline Using OPAL, GPT, and Impact-T 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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WEXD6 Electron Cloud Measurements in Fermilab Booster 556
 
  • S.A.K. Wijethunga, J.S. Eldred, E. Pozdeyev, C.-Y. Tan
    Fermilab, Batavia, Illinois, USA
  
  Fermilab Booster synchrotron requires an intensity upgrade from 4.5×1012 to 6.5×1012 protons per pulse as a part of Fermilab’s Proton Improvement Plan-II (PIP-II). One of the factors which may limit the high-intensity performance is the fast transverse instabilities caused by electron cloud effects. According to the experience in the Recycler, the electron cloud gradually builds up over multiple turns in the combined function magnets and can reach final intensities orders of magnitude greater than in a pure dipole. Since the Booster synchrotron also incorporates combined function magnets, it is important to discover any existence of an electron cloud. And if it does, its effects on the PIP-II era Booster and whether mitigating techniques are required. As the first step, the presence or absence of the electron cloud was investigated using a gap technique. This paper presents experimental details and observations of the bunch-by-bunch tune shifts of beams with various bunch train structures at low and high intensities and simulation results conducted using PyECLOUD software.  
slides icon Slides WEXD6 [4.483 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD6  
About • Received ※ 02 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 09 September 2022
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WEPA02 Beam Dynamics Studies on a Low Emittance Injector for LCLS-II-HE 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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WEPA04 Simulating Two Dimensional Transient Coherent Synchrotron Radiation in Julia 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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WEPA15 High-Field Design Concept for Second Interaction Region of the Electron-Ion Collider 648
 
  • B.R. Gamage, R. Ent, R. Rajput-Ghoshal, T. Satogata, A. Seryi, W. Wittmer, Y. Zhang
    JLab, Newport News, Virginia, USA
  • D. Arbelaez, P. Ferracin, G.L. Sabbi
    LBNL, Berkeley, California, USA
  • E.C. Aschenauer, J.S. Berg, H. Witte
    BNL, Upton, New York, USA
  • V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • F. Savary
    CERN, Meyrin, Switzerland
  • P.N. Vedrine
    CEA-DRF-IRFU, France
  • A.V. Zlobin
    Fermilab, Batavia, Illinois, USA
  
  Funding: Contract No. DE-AC05-06OR23177, Contract No. DE-SC0012704 and Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Efficient realization of the scientific potential of the Electron Ion Collider (EIC) calls for addition of a future second Interaction Region (2nd IR) and a detector in the RHIC IR8 region after the EIC project completion. The second IR and detector are needed to independently cross-check the results of the first detector, and to provide measurements with complementary acceptance. The available space in the existing RHIC IR8 and maximum fields achievable with NbTi superconducting magnet technology impose constraints on the 2nd IR performance. Since commissioning of the 2nd IR is envisioned in a few years after the first IR, such a long time frame allows for more R&D on the Nb3Sn magnet technology. Thus, it could provide a potential alternative technology choice for the 2nd IR magnets. Presently, we are exploring its potential benefits for the 2nd IR performance, such as improvement of the luminosity and acceptance, and are also assessing the technical risks associated with use of Nb3Sn magnets. In this paper, we present the current progress of this work. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA15  
About • Received ※ 04 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 17 August 2022 — Issue date ※ 31 August 2022
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WEPA34 Transfer Maps in the Hard-Edge Limit of Quadrupole and Bend Magnets Fringe Fields 705
 
  • T.V. Gorlov
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: This work has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Beam dynamics of charged particles in the fringe field of a quadrupole and a dipole magnet is considered. An effective method for solving symplectic Lie map exp(:f:) in such cases has been developed. A precise analytic solution for nonlinear transverse beam dynamics in a quadrupole magnet with hard-edge fringe field has been obtained. The method of Lie map calculation considered here can be applied for other magnets and for soft edge type of fringe field. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA34  
About • Received ※ 23 July 2022 — Revised ※ 29 July 2022 — Accepted ※ 07 August 2022 — Issue date ※ 12 August 2022
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WEPA36 Emittance Growth Due to RF Phase Noise in Crab Cavities 708
 
  • H. Huang, S. Zhao
    ODU, Norfolk, Virginia, USA
  • F. Lin, V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • Y. Luo
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
  • T. Satogata, Y. Zhang
    JLab, Newport News, Virginia, USA
  • B.P. Xiao, D. Xu
    BNL, Upton, New York, USA
  
  The Electron-Ion Collider (EIC) incorporates beam crabbing to recover geometric luminosity loss from the nonzero crossing angle at the interaction point (IP). It is well-known that crab cavity imperfections can cause growth of colliding beam emittances, thus degrading collider performance. Here we report a particle tracking study to quantify these effects. Presently the study is focused on crab cavity RF phase noise. Simulations were carried out using Bmad. Dependence of emittance growth on phase noise level was obtained which could be used for developing crab cavity phase control specifications. We also benchmarked these simulations with theory.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA36  
About • Received ※ 02 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 02 September 2022
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WEPA67 Effects of Transverse Dependence of Kicks in Simulations of Microbunched Electron Cooling 780
 
  • W.F. Bergan
    BNL, Upton, New York, USA
  • G. Stupakov
    SLAC, Menlo Park, California, USA
  
  Funding: This work was supported by Brookhaven Science Associates, LLC under contract No. DE-SC0012704 with the U.S. Department of Energy, and by the Department of Energy, contract DE-AC03-76SF00515.
Microbunched electron cooling (MBEC) is a cooling scheme in which a beam of hadrons to be cooled induces energy perturbations in a beam of electrons. These electron energy perturbations are amplified and turned into density modulations, which in turn provide energy kicks to the hadrons, tending to cool them. For simplification, previous work has modelled the electron-hadron interactions using a disc-disc model, assuming that the inter-particle kicks depend only on the longitudinal distances between individual hadrons and electrons. In reality, these kicks will also have a transverse dependence, which will impact the cooling process. We incorporate this transverse kick dependence into our simulations of the cooling process, allowing us to better understand the physics and provide improved design goals for the MBEC cooler for the Electron-Ion Collider. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA67  
About • Received ※ 19 July 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 26 August 2022
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WEPA72 Analysis of Beam-Induced Heating of the NSLS-II Ceramic Vacuum Chambers 799
 
  • G. Bassi, C. Hetzel, A. Khan, B.N. Kosciuk, 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
  
  We discuss impedance calculations and related heating issues of the titanium-coated NSLS-II kicker ceramic chambers, with the titanium coating thickness estimated from in situ measurements of the end-to-end resistance of each chamber. Power densities are calculated on the titanium coating to allow for thermal analysis with the code ANSYS and comparison with heating measurements. The impedance analysis is performed using a realistic model of the ceramic complex permittivity, and special consideration is given to the impedance calculation in the limit of zero titanium coating thickness.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA72  
About • Received ※ 03 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 26 September 2022
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WEPA73 Numerical Studies of Geometric Impedance at NSLS-II with GdfidL and ECHO3D 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
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WEPA74 Characterization of Fully Coupled Linear Optics with Turn-by-Turn Data 805
 
  • Y. Li, R.S. Rainer, V.V. Smaluk
    BNL, Upton, New York, USA
  
  Funding: This research used resources of the NSLS-II, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.
In the future diffraction-limited light source rings, fully coupled linear optics to generate round beams is preferable. While machine tune approaching to linear difference resonances, small random errors, such as quadrupole rolls, can result in fully coupled optics. Consequently, some uncertainty exists in such optics due to random errors distributions. Given beam position monitors turn-by-turn readings, the harmonic analysis method was used to characterize the coupled Ripken Twiss parameters. 		 
poster icon Poster WEPA74 [0.889 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA74  
About • Received ※ 25 July 2022 — Revised ※ 30 July 2022 — Accepted ※ 08 August 2022 — Issue date ※ 19 August 2022
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WEPA78 Proton-Electron Focusing in EIC Ring Electron Cooler 820
 
  • S. Seletskiy, A.V. Fedotov, D. Kayran, J. Kewisch
    BNL, Upton, New York, USA
  
  The Electron Ion Collider (EIC) requires a cooling of protons at the top energy. The Ring Electron Cooler (REC) is a suitable option for such a cooling. In this paper we consider an effect of a proton-electron space charge (SC) focusing on the quality of the electron beam in the REC. We show that, with properly adjusted parameters of the Ring Electron Cooler, the SC focusing in the REC cooling section does not significantly affect the cooler performance.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA78  
About • Received ※ 02 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 20 August 2022
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WEPA80 Progress on Convergence Map Based on Square Matrix for Nonlinear Lattice Optimization 823
 
  • L.H. Yu, Y. Hao, Y. Hidaka, F. Plassard, V.V. Smaluk
    BNL, Upton, New York, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
  
  Funding: DOE.
We report progress on applying the square matrix method to obtain in high speed a "convergence map", which is similar but different from a frequency map. We give an example of applying the method to optimize a nonlinear lattice for the NSLS-II upgrade. The convergence map is obtained by solving the nonlinear dynamical equation by iteration of the perturbation method and studying the convergence. The map provides information about the stability border of the dynamical aperture. We compare the map with the frequency map from tracking. The result in our example of nonlinear optimization of the NSLS-II lattice shows the new method may be applied in nonlinear lattice optimization, taking advantage of the high speed (about 30~300 times faster) to explore x, y, and the off-momentum phase space. 		 
poster icon Poster WEPA80 [5.392 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA80  
About • Received ※ 19 July 2022 — Revised ※ 26 July 2022 — Accepted ※ 08 August 2022 — Issue date ※ 10 August 2022
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WEPA85 Localized Beam Induced Heating Analysis of the EIC Vacuum Chamber Components 833
 
  • M.P. Sangroula, D.M. Gassner, C.J. Liaw, C. Liu, P. Thieberger
    BNL, Upton, New York, USA
  • J.R. Bellon, A. Blednykh, C. Hetzel, S. Verdú-Andrés
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The Electron-Ion Collider (EIC), to be built at Brookhaven National Laboratory (BNL), is designed to provide a high electron-proton luminosity of 1034 cm-2 s-1. One of the challenging tasks for the Electron Storage Ring (ESR) is to operate at an average beam current of 2.5 A within 1160 bunches with a ~ 7 mm bunch length. The Hadron Storage Ring (HSR) will accumulate an average current of 0.69 A within 290 bunches with a 60 mm bunch length. Both rings require the impedance budget simulations. The intense e-beam in the ESR can lead to the overheating of vacuum chamber components due to localized metallic losses. This paper focuses on the beam-induced heating analysis of the ESR vacuum components including bellows, gate-valve, and BPM. To perform thermal analysis, the resistive loss on individual components is calculated with CST and then fed to ANSYS to determine the temperature distribution on the vacuum components. Preliminary results suggest that active water cooling will be required for most of the ESR vacuum components. Similar approach is applied to the HSR vacuum components. The thermal analysis of the HSR stripline injection kicker is presented. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA85  
About • Received ※ 03 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 10 September 2022
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FRXD1
 Demonstration of Optical Stochastic Cooling in an Electron Storage Ring  
 
  • J.D. Jarvis, D.R. Broemmelsiek, K. Carlson, D.R. Edstrom, V.A. Lebedev, S. Nagaitsev, H. Piekarz, A.L. Romanov, J. Ruan, J.K. Santucci, G. Stancari, A. Valishev
    Fermilab, Batavia, Illinois, USA
  • S. Chattopadhyay, A.J. Dick, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  
  Optical stochastic cooling (OSC), proposed nearly thirty years ago, replaces the conventional microwave elements of stochastic cooling (SC) with optical-frequency analogs, such as undulators, optical lenses and optical amplifiers. Here we discuss the first experimental observation of OSC, which was performed at the Fermi National Accelerator Laboratory’s Integrable Optics Test Accelerator (IOTA) with 100-MeV electrons and a radiation wavelength of 950 nm. The experiment employed a non-amplified configuration of OSC and achieved a longitudinal damping rate close to one order of magnitude larger than the beam’s natural damping due to synchrotron radiation. The integrated system demonstrated sub-femtosecond stability and a bandwidth of ~20 THz, a factor of ~2000-times higher than conventional microwave SC systems. Coupling to the transverse planes enabled simultaneous cooling of the beam in all degrees of freedom. This first demonstration of SC at optical frequencies serves as a foundation for more advanced experiments with high-gain optical amplification and advances opportunities for future operational OSC systems at colliders and other accelerator facilities.  
slides icon Slides FRXD1 [32.041 MB]  
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FRXD2
 Experimental Demonstration of Multi-Function Longitudinal Beam Phase-Space Manipulation via Double Emittance-Exchange  
 
  • J. Seok
    ANL, Lemont, Illinois, USA
  • J. Seok
    UNIST, Ulsan, Republic of Korea
  
  Beam manipulation in the longitudinal direction is not straightforward due to the speed and duration of the bunch. Longitudinal manipulation usually require dedicated radio-frequency (RF) cavities and anisochronous beamlines (e.g., chicane) to control beam’s time-energy correlation (called chirp). In this talk, a new method using a double emittance exchange (DEEX) beamline was demonstrated for the first time at the Argonne Wakefield Accelerator Facility. It allows control of the longitudinal phase space using relatively simple transverse manipulation techniques. This method enables various longitudinal manipulations such as tunable bunch compression, longitudinal chirp control, and nonlinearity compensation in a remarkably flexible manner. We report proof-of-principle experiment results demonstrating three key functions of the DEEX bunch compressor.  
slides icon Slides FRXD2 [3.396 MB]  
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FRXD3 Measurements of the Five-Dimensional Phase Space Distribution of an Intense Ion Beam 910
 
  • A.M. Hoover, A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: Supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics; authored by UT- Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
No simulation of intense beam transport has accurately reproduced measurements at the level of beam halo. One potential explanation of this discrepancy is a lack of knowledge of the initial distribution of particles in six-dimensional (6D) phase space. A direct 6D measurement of an ion beam was recently performed at the Spallation Neutron Source (SNS) Beam Test Facility (BTF), revealing nonlinear transverse-longitudinal correlations in the beam core that affect downstream evolution. Unfortunately, direct 6D measurements are limited in resolution and dynamic range; here, we discuss the use of three slits and one screen to measure a 5D projection of the 6D phase space distribution, overcoming these limitations at the cost of one dimension. We examine the measured 5D distribution before and after transport through the BTF and compare to particle-in-cell simulations. We also discuss the possibility of reconstructing the 6D distribution from 5D and 4D projections. 		 
slides icon Slides FRXD3 [4.078 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-FRXD3  
About • Received ※ 03 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 02 September 2022
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FRXD4 Suppressing the Microbunching Instability at ATF using Laser Assisted Bunch Compression 914
 
  • Q.R. Marksteiner, P.M. Anisimov, B.E. Carlsten, G. Latour, E.I. Simakov, H. Xu
    LANL, Los Alamos, New Mexico, USA
  
  Funding: This project was supported by funding from the Los Alamos National Laboratory Laboratory Research and Development program.
The microbunching instability in linear accelerators can significantly increase the energy spread of an electron beam. The instability can be suppressed by artificially increasing the random energy spread of an electron beam, but this leads to unacceptably high energy spreads for future XFEL systems. One possibility of suppressing this instability is to use laser assisted bunch compression (LABC) instead of the second chicane in an XFEL system, thereby eliminating the cascaded chicane effect that magnifies the microbunching instability. An experiment is proposed at ATF to test this concept, and numerical simulations of the experiment are shown. 		 
slides icon Slides FRXD4 [4.629 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-FRXD4  
About • Received ※ 03 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 28 September 2022
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FRXD5
 Nonlinearly Shaped Pulses at LCLS-II  
 
  • N.R. Neveu, S. Carbajo, Y. Ding, J.P. Duris, R.A. Lemons, A. Marinelli, J. Tang
    SLAC, Menlo Park, California, USA
  
  Funding: DOE
With the goal of improving emittance and longitudinal phase space of the electron beam, we consider nonlinear shaping of the temporal laser profile at the cathode. The operational Ultraviolet (UV) optics installed at the LCLS and LCLS-II currently produce Gaussian shaped pulses. Our simulations show the potential to reduce emittance and increase peak brightness when comparing nonlinear UV laser shapes on the cathode to baseline Gaussian pulses at the cathode. 		 
slides icon Slides FRXD5 [3.597 MB]  
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FRXD6 Bunch Length Measurements at the CEBAF Injector at 130 kV 917
 
  • S. Pokharel, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • M.W. Bruker, J.M. Grames, A.S. Hofler, R. Kazimi, G.A. Krafft, S. Zhang
    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.
In this work, we investigated the evolution in bunch length of beams through the CEBAF injector for low to high charge per bunch. Using the General Particle Tracer (GPT), we have simulated the beams through the beamline of the CEBAF injector and analyzed the beam to get the bunch lengths at the location of chopper. We performed these simulations with the existing injector using a 130 kV gun voltage. Finally, we describe measurements to validate these simulations. The measurements have been done using chopper scanning technique for two injector laser drive frequency modes: one with 500 MHz, and another with 250 MHz. 		 
slides icon Slides FRXD6 [0.800 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-FRXD6  
About • Received ※ 02 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 01 September 2022
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