20160923-JleicIonIntegration

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Sep 23 2016 JLEIC Ion Integration Meeting (and Notes)

Ion linac parameters and extending linac baseline files to high energy (Todd)

  • Added the ion linac parameters to the JLEIC baseline parameters page.
    • Ed et al. pointed out that the pulse charge of o(<math>10^{16}-10^{18}</math>) on the wiki is clearly incorrect, perhaps by as much as <math>10^6</math>. Todd reviewed his calculations and found a <math>10^6</math> error, and fixed the spreadsheet and PDF. This should also resolve observations Ed had about space charge challenges at low energy.
  • Added TRACK code and supporting lattices to the JLEIC svn repository.
  • These parameters are currently only modeled for the low energy (134 MeV p, 44 MeV Pb) option.
  • Consulted earlier this week with Peter Ostroumov about the best way to extend the linac to high energy (280 MeV p, 100 MeV Pb)
    • Do not need additional types of HWR cryomodules with different cavities; existing cavities optimized for beta=0.3 will do.
  • Have about 7.5 MeV of energy gain per cryomodule for Pb, so need 8 more beta=0.3 cryomodules in linac for high energy.
    • This is despite final high-energy option betas of 0.64 (p) and 0.43 (Pb).
  • Expect to have parameter and lattice update for high energy option before collaboration meeting in two weeks.
  • Several people noted some concern about the length of the high energy linac variation. Todd will produce a lattice and we will check the site constraints.

Summary of current state of ion beam formation plan (Jiquan)

  • Bunch Formation Scheme (from Jiquan email Jun 24 2016)
  • Jiquan noted that he sent around a bunch formation document to some folks in late June; not much has changed since then. This will be used as the basis for the collaboration meeting talk.
    • This design has 4-6 binary splits in the collider ring, with maximum bunch length limited by injection kicker rise time.
  • Vasiliy noted that there is some concern about acceleration of long bunches and the impact on collider ring ramping time.
  • Todd also noted there is some more general concern about the collider ring ramp design, including longitudinal emittance, momentum spread, transition crossing etc.
  • Todd has some tools from Brookhaven to start looking at initial parameters for ramp design. We will iterate through ramp design and bunch formation implications in future meetings.

Comments on preliminary space charge studies for Booster injection energy options (Ed)

  • Ed noted that beam pretty much immediately dies with the existing low energy linac parameters in the wiki.
  • We noted that the pulse charges are obviously too large and miscalculated.
  • Todd updated the wiki parameters for the linac bunch intensities and will work with Ed to establish new space charge estimates.

AOB

  • Amy is splitting a talk on ion sources with Vadim Dudnikov at the collaboration meeting.
  • Yves is working with Rui and others to start developing an impedance budget
    • This partly uses ZAP for some calculations, but some calculations (e.g. IR region beampipe) require calculations with approximate expected geometry.
    • Todd is also concerned about BPM designs for the collider ring with long and short bunches (before and after splitting).
    • Vasiliy noted that Roman Pots in the ion collider ring at <math>\approx 10\sigma</math> may also have significant impedance impact.
    • Tim notes that an engineering team is starting to assemble to evaluate integration needs, e.g. power supply/magnets. BPM and instrumentation design may be part of this.

Reference Materials

Attendance

  • Jiquan Guo, Geoff Krafft, Fanglei Lin, Tim Michalski, Vasiliy Morozov, Yves Roblin, Todd Satogata, Amy Sy