General Meeting Summary 8/2/17

SHMS AEROGEL DETECTOR (Arthur, Andres, Marco,...)

• Aerogel tray exchange from SP-11 to SP-30 planned for next few days

• Discussion about events detected from outside the active area for SP-11 aerogel tray

• Cosmic data suggest that these are scintillation events
• for comparison, data from full trays show background (not from aerogel) on order 1 photoelectron

• Action Item: estimate impact of few photoelectron background on particle identification (proton rejection)

HMS AEROGEL DETECTOR (Arthur, Richard, Salim)

• CUA received 5 Burle 8854 PMTs from former SOS aerogel cherenkov detector (aerogel was n=1.05) - 2 more PMTs and the detector box are at JLab

• These PMTs are about 20 years old
• HV range up to 2500 V, tests at 2200 V show good signals on scope without noise
• Action Item: Need to check single photoelectron and quantum efficiency for these PMTs

• CUA also received 19 XP4500 PMTs, originally from MIT/Bates

• Initial checks in darkbox promising - full tests ongoing
• PMTs show small after-pulses - can be considered noise. Question: what was the helium source at MIT/Bates?

DIRC (Greg)

• Discussion about optimizations of the monitoring system for transporting SLAC DIRC bars to JLab

• prototype built at Indiana
• expect transport to happen this fall

• Discussion about sensor tests and lens prototype tests at CERN

PION AND KAON STRUCTURE FUNCTIONS (Dannie)

• Completed kinematic studies for kaons, working on pions next

• Working on offshellness correction

• Next will start looking at detector simulation to include resolutions

IMPACT OF REFLECTOR ON CRYSTAL LIGHT YIELD (Casey)

• Tested different materials, difference combinations, and different thicknesses

• Teflon performs best, mylar not very good

• Next will test additional materials including Gore reflector (that was used in SHMS aerogel Cherenkov detector construction)

• Discussion about cutting reflector to shape rather than trying to wrap