General Meeting Summary 3/29/17

DETECTORS AT JLAB

• Discussion of fire safety requirements and relocation of equipment from room 126 to semi-clean room

• SP-11 aerogel tray

• Walter's group constructed the cover - see the fit in Pic1 or in Pic2
• next, Arthur and Jonathan will install aerogel tiles, mark the tray
• action item: install SP-11 tray into SHMS and test with cosmics

• Discussion of further analysis of KPP run (golden run=488) - coordinate dependence looks good overall - a few distributions: Events x-y on aerogel surface, NPE y-dependence total sum, NPE x-dependence total sum

• run 488 used a 0.5% carbon target (see Dave Meekins notes on target specs)and the spectrometer was set for momenta of > 1 GeV/c
• Note that HMS and SHMS runs have different numbers in the Hall C logbook

• for the currently installed tray (n=1.015 aerogel) the threshold is 800 MeV this means that all particles are above threshold and PID cuts on calorimeter will not help

• Discussion of Marco's study of PMT gains - inconclusive for now.
• action item: check aerogel performance at next possible occasion, go >1500 HV for PMTs , performance should not change with gain - any setting should have the same #p.e.

• Discussion about temperature control system for NPS prototype tests

• chiller selection

• Silviu has a program to generate temperature profiles - requires input like material, conductivity
• discussion about optical isolation of individual crystals in full NPS: tedlar affects conductivity, aluminum could damage the crystal and would have to be very thin

PBWO4 STUDIES AT CUA

• Prototype assembly (Richard)

• mechanical assembly almost complete: see Fig. 1 and Fig.2
• discussion about vibration: use thicker angle, add damping, e.g. O-ring
• next: bearing, rod, calibrate setup (vertical motion, rotation, vibration), furnace

• APS-based readout (Andres)

• overall idea is to have an APD setup and then test it in a noise-controlled environment
• built an attenuator circuit since pulser (to LED) not reproducible

• initially used resistors, but (the pulse coming from the LED Driver was having a lot of reflections (with the first circuit we tried -A voltage divider-) due to the difference in the impedance). Next, did impedance matching, i.e. attenuate signal, but with same impedance as LED driver, cables, etc. (50 Ohm)

• results are encouraging - the pulse is more decent and gives this signal. The resulting ADC spectrum
• action item: there were questions about the change in offset with changes to circuit that need to be checked

TIMELIKE COMPTON SCATTERING (Vardan)

• Figure Of Merit comparison between what can be achieved with NPS/HIPS in Hall C and HDICE in Hall B

• TCS HC seems comparable with HDICE

• Next: get an independent evaluation of the analysis

NEXT MEETING: WED 12 APRIL at 10:00 AM (EDT)