Difference between revisions of "2017-04-14"

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'''Computational Physics - Y. Roblin''' <br>
 
'''Computational Physics - Y. Roblin''' <br>
  
 +
He Zhang:
 +
    - Cooling simulation for bunched electron cooling simulation at IMP: First, I checked the simulations from IMP to make sure we use the same parameters. With the same parameters, the cooling time is much shorter than before, and thus much closer to the experiment. Second, I added an RF cavity element into our cooling simulation code, JSPECT. The users can define the RF voltage, harmonic number, initial phase, and the phase of the reference particle. Starting with a coasting ion beam, now we can simulate the bunching process. Depending on the height of the RF bucket, the momentum spread may increase during the bunching, then it decreases due to the cooling effect and as the same time the bunch length decreases too. I have run a few test simulations using the IMP parameters, and the result looks reasonable. I will do more test run, and do some simulations for the coming IMP experiments.
 +
    - JLEIC collaboration meeting: Prepared the slides and gave a presentation on electron cooling simulation in the JLEIC collaboration meeting.
 +
    - Paper for IPAC2017: Finished the draft for IPAC2017 paper. The paper is about the optimization of the RF cavity heat load and trip rate for CEBAF at 12 GeV. Following Balsa’s work, we implement GA on the system and find the pareto-optimal front. More important, we investigated how to find the new PF quickly, if some cavities turned off. We proposed three different ways to generate initial population for fast convergence: scaling up the gradients, scaling up the gradients with the guidance of the heat load derivative, and adding trip rate optimized individuals to the initial population. With the strategically generated initial population, the PF can be found in about 20 seconds for up to 15 cavities off.
  
 +
 +
Yves Roblin
 +
    - Continuing beam-beam comparisons btw GHOST and BB3D. Found a much better working point for the e- ring which alleviate most of the luminosity degradation.
 +
    - Worked on the upcoming isotope experiment, prepared optics and material for the readiness review.
 +
    - Reviewed IPAC paper on RF cavity optimization
 +
    - Reviewed LDRD proposal for extending GHOST with FMM method in order to go beyond the Bassetti-Erksine approx. The proposal is now submitted (No extra funding requested for B. Terzic since its already in the other contract)
 +
    - Presented talk at the JLEIC meeting, ran the session on simulations.
 +
    - Assisting Hall A physicists for the upcoming readiness review on PREX/CREX. In particular, exploring whether or not the effect of the fringe field of the non-superconducting Q1 quadrupole affects the size of the spot on the dump.
 +
    - Prototyping the new autosteer code. Essentially ready to be tested with beam this fall. Generated test cases, comparing with real archived data. Using the Raytrace data taken by M. Tiefenback to load into ELEGANT and fit for orbit+bpm gains+magnet errors similar to what I did a few years ago with the LOCO method)
  
 
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Latest revision as of 09:05, 3 November 2017

Director - M. Spata
No report



Accelerator Physics - T. Satogata

Todd Satogata

  Previous two weeks (Apr 3-Apr 14)
    - JLEIC: Collaboration Meeting (Apr 3-5)
    - JLEIC: Side meetings (Ilya from Tech-X on spin tracking)
    - SCIDAC/ASCR proposal reviews, Rockville panel (Apr 6-7)
    - OPS: BTeam prep, meeting, Hall D difference orbit analysis
    - ODU: JMU seminar planning
    - USPAS: director committee telecon, calls
    - IPAC18: Invited abstract review, SPC/2 preparation
    - PRAB article review (start)
    - ADMIN: Laptop video card failure, repair in progress
    - VACATION: half Apr 12
  Next two weeks (Apr 17-Apr 28)
    - PRAB article review (finish)
    - ADMIN: Leadership training (Apr 21)
    - JLEIC: Ion integration, coordinate with ANL linac personnel
    - JLEIC: Ramp design, development for Booster parameters
    - IPAC17: Student poster booklet layout/production
    - IPAC18: SPC committee abstract reviews, SPC/2 preparation
    - USPAS: director committee telecon, calls

Alex Bogacz

  Previous two weeks (Apr 3-Apr 14)
    - JLEIC: Collaboration Meeting (Apr 3-5)
    - USPAS: Course development for Jan 2018 Practical Lattice Design
    - PERLE: Instrumentation and tuning
  Next two weeks (Apr 17-Apr 28)
    - IPAC paper prep (Booster optics, ER@CEBAF)
    - PRAB article review
    - ERL'17 and NuFact'17 SPC meetings
    - PERLE: prep mini start to end simulations

David Douglas

  Previous two weeks (Apr 3-Apr 14)
    - JLEIC: Collaboration Meeting (Apr 3-5)
    - PERLE: Write up tech note TN-17-014 on CSR estimates
    - JLEIC: Simulation, tech note draft on transfer kicker dynamics
  Next two weeks (Apr 17-Apr 28)
    - VACATION: Apr 19-25
    - JLEIC: Work through/write up CCR LSC effects estimate
    - JLEIC: Complete and write up reqs doc for CCR arcs
    - JLEIC: Write up "Life Hacks" for magnetized beam
    - JLEIC: Write up ERL/CCR architecture reqs/tradeoffs

Rui Li

  Previous two weeks (Apr 3-Apr 14)
    - JLEIC: Collaboration Meeting (Apr 3-5)
    - Start IPAC paper/poster prep (JLEIC collective effects)
    - Learning about fundamental RF mode/coupled bunch instability growth times
    - Discussions with Rimmer re LLRF impact on fundamental mode impedance
    - Review CSR results from Cheng-Ying and Dave on EEX beamline
  Next two weeks (Apr 17-Apr 28)
    - Finish IPAC paper/poster prep (JLEIC collective effects)
    - Evaluate impedance mode contributions to coupled bunch instabilities
    - Coordinate impedance mode contributions with Jiquan cavity design
    - Review transient CSR impedance to prep for second IPAC17 paper
    - Continue with JLEIC instability estimates

Ed Nissen

  Previous two weeks (Apr 3-Apr 14)
    - JLEIC: Collaboration Meeting (Apr 3-5)
    - JLEIC: Figured out issue with Booster emittance growth
    - JLEIC: Re-run simulations with better tunes for IPAC papers
    - Start IPAC paper prep (Booster SC, beam-beam sims)
  Next two weeks (Apr 17-Apr 28)
    - Finish IPAC paper/poster prep (Booster SC, beam-beam sims)
    - JLEIC: Improve fidelity of Booster injection/SC simulations

Chris Tennant

  Previous two weeks (Apr 3-Apr 14)
    - JLEIC: Collaboration Meeting (Apr 3-5)
    - PERLE: Simulations for CSR study
    - ERL'17: Start paper prep (entering DarkLight coauthors into SPMS)
  Next two weeks (Apr 17-Apr 28)
    - JLEIC: S2E cooler work and simulations
    - ERL'17: Continue paper prep (synthesize info from talks/papers)
    - PERLE: More simulations for CSR study?

Randy Gamage

  Previous two weeks (Apr 3-Apr 14)
    - JLEIC: Collaboration Meeting (Apr 3-5)
    - JLEIC: Coasting beam instability calculations/simulations
    - Dissertation writing
  Next two weeks (Apr 17-Apr 28)
    - JLEIC: Finish coasting beam instability calculations/simulations
    - Dissertation writing: Finish coasting beam chapter

Accelerator R and D - Y. Zhang

Slava Derbenev

   Continued conceptual study of JLEIC
   Advise He Zhang on cooling theory study 

Fanglei Lin

   Helped prepare the presentations of electron collider ring nonlinear beam dynamics study and electron polarization for the JLEIC collaboration meeting.
   Attended one-week HIAF project review at Lanzhou in China.
   Miscellaneous: attended a discussion of IR magnet specification. 

Vasiliy Morozov My main activities in the past two weeks were:

   JLEIC collaboration meeting: presentations on polarization and IR design
   Ion polarization: IPAC'17 paper preparation and solenoid compensation work
   Geometry tagging LDRD: teleconferences with collaborators and 2nd-year proposal preparation
   IR magnet design: discussions with Peter McIntyre and Tim Michalski
   Synchrotron radiation mask and detector background simulations: discussions with Mike Sullivan and Latifa's group
   Crab crossing design and simulations: work with Salvador Sosa
   Muon cooling teleconferences 

Amy Sy

   Skew PIC: Finding better solutions for nonlinear compensation by simultaneously optimizing many multipole components to control distributions with large angular spreads - previously gradually incremented the multipole order along with incrementing the angular spread. Found sextupole and octupole components that control particles with angles up to 82 mrad, where previously decapoles were needed to control the same distribution. Also analyzing the linear transfer matrix for the Skew PIC channel to see how the dynamic behavior changes with the introduction of RF - parametric resonance behavior is appears in the presence of RF, and we may be hitting another resonance.
   Merger: Refined the transition section geometry and introduced a tip angle to solenoid coils in the major bend section to offset the vertical drift of the beam center. Generalized emittance evaluation method by removing the artificial longitudinal cut imposed by the emittance calculation program - working on verifying emittance projections on tilted detector planes. Working on adding space charge into the simulation.
   Ion sources: Ran polarized ion source discussion with input from potential contributors from Muons, Inc. and Argonne. Reviewing background material on ABPIS and previous Muons, Inc. proposal narrative in anticipation of future communication with potential Argonne collaborators. 

Guohui Wei

   Did analysis of ePb collision in JLEIC IR section. Currently 10,000 events are studied. Due to the correlation between evaporation neutrons and impact parameter (b), the path length traveled in the medium following the first collision, the results are reasonable.
   Dynamic aperture study with tune scan for the JLEIC ion collider ring in cluster.
   Prepare for the proceeding paper in IPAC'17 

Yuhong Zhang

   Attended JLEIC Collaboration Meeting
   Had discussions with external participants of the collaboration meeting
   Completed two IPAC posters
   Prepared to attend the cooling experiment
   Started writing the IPAC papers 



Computational Physics - Y. Roblin

He Zhang:

   - Cooling simulation for bunched electron cooling simulation at IMP: First, I checked the simulations from IMP to make sure we use the same parameters. With the same parameters, the cooling time is much shorter than before, and thus much closer to the experiment. Second, I added an RF cavity element into our cooling simulation code, JSPECT. The users can define the RF voltage, harmonic number, initial phase, and the phase of the reference particle. Starting with a coasting ion beam, now we can simulate the bunching process. Depending on the height of the RF bucket, the momentum spread may increase during the bunching, then it decreases due to the cooling effect and as the same time the bunch length decreases too. I have run a few test simulations using the IMP parameters, and the result looks reasonable. I will do more test run, and do some simulations for the coming IMP experiments.
   - JLEIC collaboration meeting: Prepared the slides and gave a presentation on electron cooling simulation in the JLEIC collaboration meeting.
   - Paper for IPAC2017: Finished the draft for IPAC2017 paper. The paper is about the optimization of the RF cavity heat load and trip rate for CEBAF at 12 GeV. Following Balsa’s work, we implement GA on the system and find the pareto-optimal front. More important, we investigated how to find the new PF quickly, if some cavities turned off. We proposed three different ways to generate initial population for fast convergence: scaling up the gradients, scaling up the gradients with the guidance of the heat load derivative, and adding trip rate optimized individuals to the initial population. With the strategically generated initial population, the PF can be found in about 20 seconds for up to 15 cavities off. 


Yves Roblin

   - Continuing beam-beam comparisons btw GHOST and BB3D. Found a much better working point for the e- ring which alleviate most of the luminosity degradation.
   - Worked on the upcoming isotope experiment, prepared optics and material for the readiness review.
   - Reviewed IPAC paper on RF cavity optimization
   - Reviewed LDRD proposal for extending GHOST with FMM method in order to go beyond the Bassetti-Erksine approx. The proposal is now submitted (No extra funding requested for B. Terzic since its already in the other contract)
   - Presented talk at the JLEIC meeting, ran the session on simulations.
   - Assisting Hall A physicists for the upcoming readiness review on PREX/CREX. In particular, exploring whether or not the effect of the fringe field of the non-superconducting Q1 quadrupole affects the size of the spot on the dump.
   - Prototyping the new autosteer code. Essentially ready to be tested with beam this fall. Generated test cases, comparing with real archived data. Using the Raytrace data taken by M. Tiefenback to load into ELEGANT and fit for orbit+bpm gains+magnet errors similar to what I did a few years ago with the LOCO method) 

Diagnostic Development - K. Jordan