# 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($10^{16}-10^{18}$) on the wiki is clearly incorrect, perhaps by as much as $10^6$. Todd reviewed his calculations and found a $10^6$ 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 $\approx 10\sigma$ 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.

## Attendance

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