Thursday, February 27, 2014 2:30pm EST - Compton

Previous meeting: Tuesday, December 10, 2013 11am EST - Compton

Tentative Agenda

1. Updates
   1. laser (Kent)
   2. DAQ (Bob/Alex)
   3. photon detector (Greg/Vahe)
   4. electron detector (Juliette/Dipangkar)
   5. magnetic field mapping (Kent)
   6. beamline status/accelerator schedule (Alex)
2. consequences of restructuring (Dave/Thia)
3. Next meeting time

Minutes

Attending: Juliette, Dustin, Dave, Alex, Brian, Greg, Kent

1. Updates - Near term and long term goals, mostly near term (DVCS, PREX/CREX)
   1. laser (Kent -> Dave)
      1. near term - getting running again (how it was set up before)
      2. few kW green power (easier then IR)
      3. green good for PREX
      4. work in hall (not in laser lab - 2nd floor ARC)
      5. Chuck Long (spectrometer group - Jack Segal running)
      6. single-pass frequency doubling only problem (expertise at the lab)
         1. still trying to locate parts - crystal (several purchased)
         2. thermoelectric chillers to control temp
         3. stage still on table
         4. Abdurahim - thesis - photos, etc.
      7. trying to organize after restructuring
      8. Just photon okay for DVCS (don't want to break anything :))
      9. actuators for optics (after laser is running)
      10. with 12 GeV, green won't fit in beampipe at 12 GeV - redesign e- det can
      11. small slot - French connection? - redesigned?
      12. last real-world experience - power 5kW? - mirrors degrade in tunnel
   2. DAQ (Bob/Alex)
      1. put computer back in counting house
      2. trying to run the flash ADC DAQ on it
      3. High flip rate capability of the DAQ (MOLLER)
         1. old DAQ - ran at 30 Hz
         2. trigger supervisor, event triggered DAQ
         3. PREX won't use e- det - flash ADC with photon det
   3. photon detector (Greg/Brian)
      1. existing GSO brought back to CMU
         1. modified so it will fit
         2. more adjustability - need some safety stops on xy table
         3. eventual plan - two detectors one for higher energy
      2. analyzing power factor of 2 with green laser
      3. with GSO photon energy is not as much of a factor
      4. photon used for DVCS
      5. looking at PbW for 12 GeV
         1. no timeline
         2. Sirish had a source for large crystal - Shanghai?
         3. 2cm square are common - wrap them together... if no choice
         4. 3% would be pretty useful for DVCS
         5. Hall C four crystals will fit (but not the box they're in)
      6. cooling PbW
         1. light output fluctuates near room temp.
         2. more light with cooler - 15 C?
         3. need to calibrate with spectrum in counting, and would be distorted
         4. if energy changes, then effects from that, too
   4. electron detector (Juliette)
   5. magnetic field mapping (Kent)
   6. beamline status/accelerator schedule (Alex)
      2. DVCS in the fall
      3. 12 GeV halo bigger
      4. Synchrotron light at 12 GeV running
2. consequences of restructuring
3. next meeting time

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