Thursday, September 26, 2013 2pm EST - Compton

Previous meeting: Wednesday, May 1, 2013 2pm EST - Compton

Tentative Agenda

1. Sirish - beamline/accelerator
2. Bob - DAQ status
3. Vahe - photon det
4. Alex - e- det status pdf
5. Kent - field mapping
6. Peiqing - Qweak e- det electronics
7. Juliette - various e- det issues
8. Next meeting time

Minutes

Attending: Juliette, Dipangkar, Greg, Bryan, Bob, Alex, Sirish, Ryan, Thia, Peiqing, Vahe, Kent, Mapalei

1. beamline (Sirish)
   1. 12 GeV construction winding down, mostly finished
   2. beamline is being buttoned up
   3. pump down and final alignment soon
   4. synchrotron suppression design and installed, field mapping
   5. minor things for photon detector
      1. needs to be elevated
      2. interference with a scanning detector (above GSO crystal) - could hit the beamline (needs to be looked at)
      3. could commission without the scanning scintillators (radiation issue?)
   6. gearing up for commissioning/documentation
   7. getting beamline ready for commissioning in February
2. DAQ Upgrade (Bob)
   1. commission old DAQ soon
   2. VXS-based pipelining CODA
   3. FADC - photon, VETROC - electron
   4. DT at 410 kHz
   5. by February could have this crate in the Hall and try to merge with CMU DAQ
3. electron detector (Alex)
   1. time is too short to look at cosmics with scintillators
   2. can control the HV supplies for the thin and thick detectors remotely
   3. brackets for scintillator paddles never ordered
   4. removing from can and trying to test again
4. photon detector (Vahe)
   1. GEANT 4 simulation of photon detector using Pb glass
   2. linearity, energy resolution
   3. more reliable than just energy deposition
   4. collimator and incident photons and detector
   5. generates Compton events
5. simulations (future discussion)
   1. code from Sirish - whole chicane
   2. GEANT3 - Compton separate processes (Hall C)
   3. synchrotron radiation (used GEANT3) - lots of low energy photons... bremsstrahlung
   4. GEANT4 wins big in photon transport...
6. field mapping (future discussion)
   1. never got into region where field was absolutely stable
   2. jump in measured field in bore
   3. report being worked on
7. Qweak Compton electron detector electronics
   1. modified board from TRIUMF liquid Xenon project
   2. tests at JLAB showed noise and interchannel correlations
   3. crosstalk virtually eliminated in V3
   4. gain variation (trace routing - predictable) could be improved
   5. S/N ratio of final boards
      1. gains - 100mV/fC
      2. 8000 e-, noise as low as 100 e- per channel with calibration input
      3. diamond efficiency strip by strip different - some channels have very low numbers of electrons
   6. Kapton cables added capacitance
   7. single-channel prototype board - ask Jeff Martin - test single channels
8. Next meeting first week of November?

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