Thursday, May 21, 2015, 11:00am EDT - Compton

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Revision as of 12:27, 21 May 2015 by Gaskelld (Talk | contribs) (Minutes)

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1. Dial Toll-Free Number: 1-888-240-2560 (U.S. & Canada)
2. International participants dial:
Toll Number: 1-408-740-7256
3. Enter meeting ID:140287970


Meeting room=F227 in Cebaf Center


  • Update on test at 2 pass (Gaskell) pdf


  • Lots of DAQ work planned for this summer (Bob - if available)
    • Remove old Saclay counting DAQ
    • Put in new photon counting DAQ
    • How will this impact electron detector?
    • VETROC tests

Electron detector

  • Updates from Alexandre - did we learn anything from the little bit of beam we took?
    • Cannot get closer than 22 mm
    • Run 1370 : 1857 triple coincidence ABD, 1634 no hit plane C, 223 hits plane C at thresold 21 : 12 % efficiency though cannot conclude since it could be photons and corellated noise
  • Updates from Manitoba

Photon Detector

  • Analyzer - would be nice if we could get background subtracted asymmetries from 2 pass data.
  • Plans for upgrades or improvements this summer?


  • Primary goal is implementing polarization setting and monitoring a la Hall C.
  • Other tasks: Gather spares, get laser lab fully functional


  • Dave should get the Bluejeans stuff working properly - this will make life easier for future meetings.
  • Dave went over 2 pass commissioning stuff - a lot of things went well!
  • Electron detector commissioning trickier - at "22 mm"from beam , Alex starting seeing more rate in photon detector, ion chambers tripped. Info from BPM between dipoles 3-4 suggests beam might have been at larger y than expected.
    • 2 example spectra shown - not clear if we're seeing "real" signal or not. Might be coming from photons. No clear Compton events.
    • Plans for summer include removing detector to inspect, get DAQ working better. Try with QWADs?
  • Manitoba making progress on electron detector - but it takes time getting all the parts, connectors etc. Mitra has some questions about QWADs - will talk to Dipangkar offline.
  • Photon Detector
    • Gregg notes that working on the Analyzer is a plan for the summer. Also thinks we might need something for simple online monitoring since old DAQ is going away.
    • Detector work (Brian): Add temperature monitoring to detector. Would like to do more linearity measurements at CMU - Dave will check on whether the old loan agreement is still in force.
  • Alexandre will submit proposal to EIC R&D - focus on vacuum chamber adapter that would allow putting Hall C detector in Hall A and vice versa (?).
  • Dave notes that Elke Aschenauer suggested a meeting of BNL and JLab polarimetry experts to discuss strategy at an EIC.