Zoom link: Please contact David Armstrong for meeting coordinates, or check with the MOLLER meeting calendar.

Agenda

Attendance

Vlad, David, Rakitha, Lasitha, James, Nilanga, Shashini, brynna, Chandan, Jaydeep, Huong

Trigger Scintillator/Rotator interference (David) - Lasitha has a new CAD design of TS/PMT connection that avoids mechanical interference, Chandika confirms. This has the PMTs emerging in radial direction, and will stick out a bit from the GEM holder, but that causes no new problems. Need to detail how PMT is held by GEM holder (not by TS frame).
Trigger Scintillator tests (Rakitha) - after suggestions from last meeting, have increased thresholds on the cosmic paddles (to reduce spurious triggers) and retested the first production TS, with no other changes to the scintillator or its electronics. Now get 99.6% efficiency, uniform over TS. ADC spectrum looks reasonable, well-separated from pedestal. Conclusion - earlier low efficiency results were not correct due to fake triggers. Still probably want to minimize WLS bending, which is an advantage of the new mechanical design. The 1PE level is defined as about 20 counts above pedestal, rough estimate > 5 PEs for almost every event. Still don't fully understand timing spectrum (data taken using CAEN V1720 digitizer, 250 MHz clock (4 ns time bins) - sigma appears to be of order 5 ns, but spectrum has odd structure. Will study in more detail.