20170602-JleicIonIntegration

Apr 21 2017 JLEIC Ion Integration Meeting

Report at R&D Meeting

• 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

Booster h=1 Capture

• 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)

Booster Ramping

• 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)

Booster Space Charge

• 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:

Linac/Booster Pb Charge State

• 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

Other Items

• AOB

Reference Materials

• JLEIC Fall 2016 Collaboration Meeting (Oct 5-7 2016, InDiCo)
• JLEIC Spring 2017 Collaboration Meeting (Apr 3-5 2017, website)
• JLEIC svn repository
• Last meeting (Mar 10 2017)

Attendance

• TBD