RTML and Linac Design: Update

1
RTML and Linac Design Update

• PT
• 12-Dec-2005

2
RTML (Ring to Main Linac)

• Baseline configuration developed and uploaded to
  BCD wiki
• Most beamlines exist only as descriptions with
  very approximate lengths, magnet counts, etc
• Bunch Compressor exists as actual lattice files,
  but still somewhat rough
• 2-stage Raubenheimer-Tenenbaum-Wolski (RTW)
  design with FCDC wiggler configurations
• PT selected as RTML Area Group (AG) design
  guru, with Eun-san Kim
• Willing to trade away the job for 1 a package
  of Tic-Tacs

3
RTML (2)

• Next steps to proceed in paralllel
• Start and/or continue design of non-controversial
  subsystems
• Betatron collimation, turnaround, spin rotator
• Study options for shortening system
• ESK-style single chicanes for BC
• Enhanced-FCDC wiggler
• Elimination of 1 skew correction section and/or 1
  laser wire emittance station
• Work with DR Area Group to define extraction
  region (DRX)
• Work with technical and global groups to begin
  costing of RTML

4
Main Linac

• Baseline configuration 8 cavity cryomodules, 1
  quad/4 modules, curved to follow curvature of a
  cue-ball earth (ie, mean radius of curvature
  6370 km)
• Not mentioned in BCD, but I like a 75/60 degree
  phase advance per cell
• Positron production wiggler at 150 GeV
• Some controversy over BPM resolution and other
  diagnostics/instrumentation
• Many details still to be worked out

5
Main Linac (2)

• K. Kubo has performed interesting studies on
  emittance preservation in curved main linac
• Proposes tuning orbit such that ?0 at D quads
  improves/eases emittance tuning
• Curvature so small that we can select this orbit,
  or others, during running (ie, the orbit
  described above does not constrain linac design
  or installation)
• Much work to be done on this general topic
• Also in RTML and BDS

6
LET Meeting?

• Tentative plan to hold meeting of emittance
  police worldwide in early Feb 2006
• Either at CERN or at SLAC
• A real WORKshop
• Plan to have sessions devoted to running
  simulations which would be reported on the next
  morning assign and collect homework
• All aspects of LET emittance tuning,
  diagnostics, algorithms, spin propagation