Difference between revisions of "20170602-JleicIonIntegration"

Revision as of 09:37, 2 June 2017

Andrew Hutton and his student Andrew Dotson have need of canonical ion collider ring harmonic numbers.
- There is some confusion about the official baseline numbers, with inconsistencies between
  - the Jun 29 2016 Study of Beam Synchronization at JLEIC arxiv note (h=3422-3437)
  - Jiquan's fall 2016 collaboration talk (h=3584)
  - Shaoheng's Ion ring RF parameters as linked in the Ion Collider Ring Requirements and Parameters area of the JLEIC Baseline Parameters wiki. (h=6832?)
Jiquan is working on a tech note based on a spreadsheet that has ion collider h=3584-3592 (with stretch goal to 3594).
- h=3584 baseline is consistent with the fall collaboration meeting slides (slide 5), with h=28 split 2⁷ times.
Path forward:
- Identify Jiquan as owner
- Establish consensus parameters (Todd favors h=3584 which is latest Jiquan documented baseline)
- Update appropriate documentation, particularly JLEIC Baseline Parameters wiki.
- Disseminate expectation that JLEIC Baseline Parameters wiki should be current canonical parameter information.

Todd and Ed presented slides on Ion Injector Complex/Parameter Development at the Thu Apr 20 R&D Meeting
This summarized some recent work on Booster h=1 capture, ramp development, and Synergia space charge simulations

Done:
- 30 kV seems like the appropriate voltage for capturing initial coasting beam
- 100 ms linear RF voltage ramp is workable (see presentation); faster may be feasible
- esme simulation is relatively straightforward: RMS sigmaE/E goes from 3.1e-3 Gaussian (coasting) to 5.4e-3 parabolic (bunched)
- Have tools in place to quickly make esme "movies"
To Do:
- Develop consensus injection energy spread (Todd/Ed/Brahim)
- Determine how fast <math>d^2B/dt^2</math> can be (Todd/Peter)
  - Emails ongoing: Peter raises interesting questions about snapback and dynamic superconducting magnet effects
- Turn on injection longitudinal space charge for realistic intensities
  - Compare to Synergia (Ed/Todd)

Done:
- Tools in place and under development for generating ramp parameters
- f(RF) = 700 to 1030 kHz as input to RF design
- h=1 through Booster to extraction appears appropriate
To Do:
- Add esme ramp generation to RampDesigner tool
- Start simulating early acceleration ramp with esme (space charge off, then on)
- Pursue cooling evaluation at 2 GeV (bunched or coasting beam? Todd/He/Ed/...)
- Evaluate addition of realistic impedances (Todd/Rui)

Done:
- Resolved chromatic resonance crossing problems in earlier simulations; reduced momentum spread
- Using default working point (7.517,5.493) and bare chromaticities (-13.9,-11.5)
- Injection emittance growth: x5-8 over hundreds of turns (~500 us)
- Cooling porch emittance growth more modest (x1.5-2); no growth seen at extraction
To Do:

ANL has mostly been simulating/optimizing the low energy linac (c.f. HB'16 talk/paper by Ostroumov)
- This affects charge state and stripping optimization, but does not affect latest optimizations to handle RFQ heavy ion losses
- Heavy ion source expected to have 1-2 pi mm-mrad normalized emittance; which is it?
Brahim has noted that 67+ may not be the optimal charge state for the baseline high energy linac
Brahim and Todd are continuing to discuss
- Tradeoff of space charge vs stripping efficiency/pulse intensity
- Todd's initial feeling is that this is a relatively flat optimization

@@ Line 2: / Line 2: @@
 ==Jun 2 2017 [[JLEIC-Ion-Integration-Meetings|JLEIC Ion Integration Meeting]] ==
-==== Harmonic Numbers ====
+==== Collider Ring Harmonic Numbers ====
-* Andrew Hutton and his student Andrew Dotson have need of canonical harmonic numbers.
+* Andrew Hutton and his student Andrew Dotson have need of canonical ion collider ring harmonic numbers.
 ** There is some confusion about the official baseline numbers, with inconsistencies between
 *** the [https://arxiv.org/abs/1606.09117 Jun 29 2016 Study of Beam Synchronization at JLEIC] arxiv note (h=3422-3437)
@@ Line 10: / Line 10: @@
 * Jiquan is working on a tech note based on a spreadsheet that has ion collider h=3584-3592 (with stretch goal to 3594).
 ** h=3584 baseline is consistent with the fall collaboration meeting slides (slide 5), with h=28 split 2<sup>7</sup> times.
+* Path forward:
+** Identify Jiquan as owner
+** Establish consensus parameters (Todd favors h=3584 which is latest Jiquan documented baseline)
+** Update appropriate documentation, particularly JLEIC Baseline Parameters wiki.
+** Disseminate expectation that JLEIC Baseline Parameters wiki should be current canonical parameter information.
 ----