Wednesday, March 4, 2020, 2:00 pm EST
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Contents
Agenda
Meeting room = Counting House Meeting Room
General
- Compton position lock, orbit
- Periodic low current runs
- Decreasing photon detector rates [1]
Electron detector
Laser
- Laser polarization systematic tests [5]
- Low threshold vs. high threshold spectra at full and half gain (low current): [6]
Photon Detector
- Spectrum fitting for collimator offset (low threshold, high threshold)
Analysis
- Online analysis results
- Polarization vs. time
Minutes
Mark, Michael G, Alex C, Bob M, Chip, Iris, Kent, Dave, Alex, JC, Amali,
- Photon Detector
- Adam did jaws test, 28 Feb.
- Jaws aperture at 8 mm (should let most through) but cut everything. Are jaws not aligned with collimator?
- Adam took pictures in access. Jaws center look look to be offset low by a few 4 mm. [7]
- Home position puts jaws in similar position to the finger (which see interactions.)
- Adam to show finger scan data at next meeting.
- Try running with jaws wide open for a run?
- Dropping accumulator size versus time (about 15% over a couple of weeks.) [8]
- Compton edge is same, so it's not gain change.
- Spot size change (we've seen changes at the target.) Study with vertical scan data.
- Polarization change with time. Dropped and then recovered with spot move. (Appears to be QE.)
- Study the spectrum with different gains and trigger thresholds. There appear to be issues at low energy which might be triggering on reflections. [9] Can randoms be used to help with this? Mark, Amali, JC will meet to discuss.
- Adam did jaws test, 28 Feb.
- Laser
- Gaskell found some options to study the laser polarization but needs to be repeated from different starting point.
- Electron Detector
- Discussions about noise on the detector.
- Running at block 1 leads to missed MPS triggers.
- Helicity decoding algorithm was confirmed.
- Analysis
- Polarization versus time plots.