Oct 13, 2011 SiPM Electrical and Cooling revised

Action Items from previous meetings

1. Carl to check instability of LED (as a possible contributor to sensor output changes) (Carl) Jack confirmed the instability was related to low photoelectron yields
2. Chris to check HV specs on coax cable. (Needs to hold at least 80 V). Greater than 200 V rms, breakdown voltage of 640 V.

Tentative Agenda

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
   • Progress, EVMS updates next week
4. SiPM testing (everyone)
   1. Light source / optics
   2. Electronic boards
   3. Cabling
   4. Cooling plate
   5. Other?
5. Mechanical (Jim)
6. Mechanical drawings (Chuck)
7. Geometry (Elton)
8. Temperature compensation (Jack)
9. Preamp-summing (Fernando)
10. Granularity (Elton)

Minutes

Attending: Carl, Chris, Scot, Jim, Ivan, Elton.

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
   • Progress, EVMS updates next week
4. SiPM testing (everyone)
   1. Light source / optics
      • completed
   2. Electronic boards
      • Boards have been completed by Chris. Fernando has visually checked the pdf file, but wants to verify the circuit files. Once Fernando signs off on them, Chris will go out for quotes to be ready to order once funds become available.
      • CAEN interface boards are completed, but awaiting funding.
   3. Cabling
      • cables are in hand.
   4. Cooling plate
   5. Other?
5. Mechanical (Jim)
   • Drawings proceeding, Chuck will get back to this next week
   • Items to be finalized: standoff locations need to be confirmed by Fernando. Chris as entered them onto the layout and they seem ok .Location and room for UFL connector for thermistor needs to finalized.
6. Mechanical drawings (Chuck)
7. Gluing/assembly (Scot)
   • Scot has issued reqs for Cu tubing, epoxy, standoffs, RTV sensors, but waiting on funding
   • Gluing tests have been completed for various epoxy samples
   • Mechanical comb/fingers are considered for fixtures for gluing the light guides into correct position. Jim will sketch one out and iterate with Scot.
8. Temperature compensation (Jack)
   • Review postponed till next week
   • One question raised is one of voltage draw as SiPMs age. The current draw on first articles is less than 4 microA.
9. Preamp-summing (Fernando)
   • Interconnect boards can be completed assuming the additional layer is implemented.
10. SiPM testing (Ivan)
    • New test setup is running without DAQ
    • Showed first scope data indicates that the pixel dead time is less than about 40 ns. Will continue to work on getting the test setup working and connecting to the DAQ,