journal

• Hall-A beam transport issues    OPS SELECT
  2008-11-19 Wed 11:06
  Meet with Hall-A personnel (Chudakov, Saha, RC) and optics on call (Benesch, Krafft, Zhang) on why the beam is not centered through their line. The main problem they are trying to solve is
  • Minimize the amount of steering at the start and end of m{\o}ller setups.

  The beam is not centered at the M{\o}ller target due to:

  1. A shift in the compton chicane beam pipe, resulting in non-standard beam transport at the exit of the beam pipe
  2. Non zero target locations requiring that all the correctors in the beamline downstream of the compton to be invoked to get the beam to the target and transport to the dump.
  3. This configuration does not put the beam at the M{\o}ller target center.

  Basically the line is over constrained. There are four constraint locations.

  1. Compton
  2. M{\o}ller Target
  3. Experimental target
  4. Dump

  And not enough knobs to satisfy the constraints. The following tasks are to be pursued:

  • TODO Verify BPM SOFs and GOFs are properly loaded    OPS
    
  • TODO Create a save set for M{\o}ller runs in A    OPS
    Either save the corrector values for the next M{\o}ller setup or dig them out from the Moller setup on 2008-11-17 Mon
  • TODO Investigate correcting beampipe shift in Compton location    HallA
    
  • TODO Re-survey the Harps    HallA OPS
    Determine if the survey group has re-surveyed the harps, if not schedule this, if so communicate the new values to OPS so that they can be loaded into the Harp software.
  • TODO Investigate adding corrector strength downstream of compton    HallA
    
  • TODO Investigate adding diagnostics to aid quad centering in M{\o}ller region    HallA