Author: Emery, L.
Paper Title Page
MOPAB043 Validation of APS-U Beam Dynamics Using 6-GeV APS Beam 189
 
  • L. Emery, P.S. Kallakuri, R.R. Lindberg, A. Xiao
    ANL, Lemont, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Several beam measurements at the Advanced Photon Sources were done with a lowered-energy beam of 6 GeV in order to verify or validate calculation codes and some predictions for the APS-U. Though the APS lattice is obviously different from that of the APS-U some aspects of the beams at 6 GeV are similar, for example, the synchrotron radiation damping rate. At 6 GeV, one can also store more current and run with a higher rf bucket allowing the characterization of larger momentum aperture lattices. We report measurements (or plans of measurements) on general instabilities thresholds, lifetime, and other subtle effects. The important topic of ion instabilities at 6 GeV is covered in a separate paper by J. Calvey at this conference.
 
poster icon Poster MOPAB043 [0.829 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB043  
About • paper received ※ 20 May 2021       paper accepted ※ 23 June 2021       issue date ※ 10 August 2021  
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MOPAB046 Plan for Operating the APS-Upgrade Booster with a Frequency Sweep 201
 
  • J.R. Calvey, T.G. Berenc, A.R. Brill, L. Emery, T. Fors, K.C. Harkay, T.J. Madden, N. Sereno, U. Wienands
    ANL, Lemont, Illinois, USA
  • A. Gu
    UCB, Berkeley, California, USA
 
  The APS-Upgrade presents several challenging demands to the booster synchrotron. Swap-out injection requires the booster to capture a high charge bunch (up to 17 nC), accelerate it to 6 GeV, and maintain a low emittance at extraction for injection into the storage ring. To accommodate these conflicting demands, the RF frequency will be ramped between injection and extraction. However, the RF cavity tuners will remain static, which means the couplers will need to withstand a high reflected power at extraction. This paper presents a plan for a system that will meet the requirements for injection efficiency, extracted emittance, and equivalent power at the coupler. Results from tracking simulations and beam studies with a frequency ramp will also be shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB046  
About • paper received ※ 28 May 2021       paper accepted ※ 02 June 2021       issue date ※ 26 August 2021  
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MOPAB077 Anomaly Detection in Accelerator Facilities Using Machine Learning 304
 
  • A. Das
    Stanford University, Stanford, California, USA
  • M. Borland, L. Emery, X. Huang, H. Shang, G. Shen
    ANL, Lemont, Illinois, USA
  • D.F. Ratner
    SLAC, Menlo Park, California, USA
  • R.M. Smith, G.M. Wang
    BNL, Upton, New York, USA
 
  Synchrotron light sources are user facilities and usually run about 5000 hours per year to support many beamlines operations in parallel. Reliability is a key parameter to evaluate machine performance. Even many facilities have achieved >95% beam reliability, there are still many hours of unscheduled downtime and every hour lost is a waste of operation costs along with a big impact on individual scheduled user experiments. Preventive maintenance on subsystems and quick recovery from machine trips are the basic strategies to achieve high reliability, which heavily depends on experts’ dedication. Recently, SLAC, APS, and NSLS-II collaborated to develop machine-learning-based approaches aiming to solve both situations, hardware failure prediction and machine failure diagnosis to find the root sources. In this paper, we report our facility operation status, development progress, and plans.  
poster icon Poster MOPAB077 [1.240 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB077  
About • paper received ※ 16 May 2021       paper accepted ※ 14 June 2021       issue date ※ 01 September 2021  
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TUXA01 Advances in Understanding of Ion Effects in Electron Storage Rings 1267
 
  • J.R. Calvey, M. Borland, T.K. Clute, J.C. Dooling, L. Emery, J. Gagliano, J.E. Hoyt, P.S. Kallakuri
    ANL, Lemont, Illinois, USA
 
  Ion instability, in which beam motion couples with trapped ions in an accelerator, is a serious concern for high-brightness electron storage rings. For the APS-Upgrade, we plan to mitigate coherent ion instability using a compensated gap scheme. To study incoherent effects (such as emittance growth), an IONEFFECTS element has been incorporated into the particle tracking code ELEGANT. The simulations include multiple ionization, transverse impedance, and charge variation between bunches. Once these effects are included, the simulations show good agreement with measurements at the present APS. We have also installed a gas injection system, which creates a controlled pressure bump of Nitrogen gas in a short section of the APS ring. The resulting ion instability was studied under a wide variety of beam conditions. For cases with no or insufficient train gaps, large emittance growth was observed. IONEFFECTS simulations of the gas injection experiment and APS-U storage ring show the possibility of runaway emittance blowup, where the blown-up beam traps more ions, driving further instability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA01  
About • paper received ※ 24 June 2021       paper accepted ※ 27 July 2021       issue date ※ 10 August 2021  
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