Compton Meeting, June 2, 2011

Previous Meeting: Compton Meeting, May 23, 2011

Following Meeting:

Agenda

Laser

1. Final dates for RadCon support
2. Transfer function measurement
3. Modifications to the LabView program

DAQ

1. Update on summer upgrade plans

Photon detector

1. Replay:
   1. Pedestals
   2. Analyzer status
2. PbWO4:
   1. Detector modification update

Electron detector

1. Analysis
   1. Update on analysis

Minutes

Attendance: Amrendra, Don, Manolis, Juan Carlos, Seth, Mark (chair), Wouter (minutes)

• Introduction Seth, working as REU summer student on LabView controls for laser polarization measurement

• Laser
  1. Mark will create atlis for radcon support to break vacuum
  2. LabView (Seth)
     • got used to LabView during first week
     • laser polarization measurement when light comes out of cavity (rotate polarizer to measure linear polarization)
     • added pause button, added delay to flipper (get rid of early signal spike)
     • all channels on same graph, working on error bars now
  3. Postpone transfer function measurement until after Qweak collab meeting (June 22--24), now start on June 27, Mark will double-check for conflicts with SAD schedule
  4. Measure gain/linewidth/etc precisely for NIM paper on laser cavity

• DAQ
  1. Spare CPU board (6100) arrived at W&M, will bring to JLab, will get used in electron test stand

• Photon detector
  1. PbWO4 modifications
     • Big bolt on stand might interfere with thermos, or would have to reposition PLT on thermos
     • Thermos measurements 12 inch (z) by 10 inch (width) by 9 inch (tall)
     • Great big styrofoam box, hopefully only for test
     • No room for lead under detector, lowering stand seems lot of work, room for 1 inch lead, need to find narrow lead, see picture.
     • Thermal model of thermos: total power of Compton signal, is there a gradient?
     • Hamlet wants to install fibers only once, Juan Carlos will look up fibers
     • Gamma beam profiler system: quote on XY translation stage (travel range of 6 inches), needs to be developed during summer, two scintillators with small PMT
     • Monte Carlo: modify geant3 to write events, then throw those into geant4 model of detector
  2. Replay
     • Mark collected info on pedestals, should be accurate enough for replay, Wouter requests table with run range where which pedestal is valid, and divide by number of samples
     • Kent is interested in also seeing the beam on, laser on/off pedestals, in addition to what is posted in elog 119
     • Analyzer status: BCMs are working now, combined BCMs in progress, same procedure for BPMs so should be straight-forward porting

• Electron detector
  1. Analyzer: added event mode reading, not yet possible to calculate asymmetries
     • Only Amrendra working on this, Don created some macros
     • Weighting not done correctly (?), normalization by current
     • Electron detector meeting Thursday 4pm