Wednesday, March 18, 2020, 2:00 pm EDT

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Agenda

Meeting room = None. Remote only.

General

• Keep taking data!

Electron detector

• QWAD preparation progress
• Analysis updates

Laser

• Laser polarization systematic tests: Preliminary results from HWP=73 and 56 deg. [1], [2]
• Other options for "reasonable" values of RRPD: [3]

Photon Detector

• Compton edge decreasing [4]
• Steering vs. spectrum [5]
• Spectrum fitting for collimator offset: Target dependence? Drifting gain + low amplitude backgrounds?
• LED run

Analysis

• Online analysis results
• Polarization vs. time

Minutes

Mark D, Dave G, Adam Z, Kent P, Brian Q, JCC, Cip G, Amali P

1. Photon Detector
   • Table scan: Epics logger stopped writing to the CODA file so the scan is very difficult to recover. Should be redone after procedures are made more robust.
   • Planned systematic study of angles of the electron beam will be done ASAP after the Moller today.
   • Possible new additional background from calcium that was not observed earlier. Amali investigating.
   • Tube gain is decreasing but still completely functional. Increasing the voltage to recover the gain might affect the linearity.
   • Pulser trigger doesn't work when there is beam. Need someone to verify the trigger logic in the hall. Opportunistic access.
2. Laser
   • Systematic checks wen't well. Other systematic tests are the "second solution" of the same sign or to change the sign. elog 575
3. Electron Detector
   • QWADs in EEL126 for channel adjustment.
   • Possible access to reinstate old system.