Jan 20, 2011 SiPM Electrical and Cooling

Background information

• Files for discussion
• Hall D BCAL Readout Mechanical Concept (Jim Fochtman)

Tentative Agenda

1. Review schedule and list of "deliverables"
2. First article testing (Carl and Yi)
3. Mechanical cooling (Jim)
4. Temperature compensation (Jack)
5. Preamp-summing (Fernando)
6. Discussion

Minutes

Attendees: Jack, Chuck, Jim, Yi, Carl, John, Elton, Fernando.

1. Announcements
   • Next meeting will be on Jan 27, at 3 pm.
2. Review schedule and list of "deliverables"
   • Elton summarized this task as part of the 12 GeV project and the need to show progress and complete in the scheduled timeframe. According to the P6 project schedule, this activity was to be completed last year. Based on various circumstances we are already behind. The goal is for a complete prototype by May of this year.
3. First article testing (Carl and Yi)
   1. Carl
      • Basic mockup with 16 channels is almost working (lacks some cables which are on order)
      • Labview DEMO software which talks to the relevant boards has been useful to get the system working, but effort is needed to make appropriate changes.
   2. Yi
      • Would like to help out with the software control
      • Made measurements on SiPM using 2nd irradiation. Shows that previous annealing at 60 deg annealing has not impact on future irradiation.
      • Annealing rate at 40 deg is about 2-3 days (still under test), compared to <1 day at 60 deg. Therefore, annealing at 40 deg is probably fine for the experiment.
      • Has requested a key to the lab
      • Would like to put in order for testing parts. Elton encouraged him to do so.
4. Mechanical cooling (Jim and Chuck)
   • Much discussion regarding the system suggested by Jim on how the cooling is accomplished.
   • Fernando requested that Jim run his simulation for the situation when the electronics was turned off.
   • Under the present scheme, the cooling plate is kept at the constant temperature of 0 deg C; the nitrogen is heated by the electronic boards, which is in contact with the plate. Heat is also lost through the walls of the enclosure. Approximately 8 W are dissipated by the cooling system when the nitrogen is at room temperature. The electronic boards dissipate 9W (amp/summing) and 3.6 W(temp stabilization) respectively.
   • It was suggested that Chuck and Jim develop a prototype enclosure for testing the mechanical cooling. It would have the nominal dimensions for the full size calorimeter end, but mockups for the light guides and heat sources (boards with resistors) in lieu of actual electronics). It would also need to develop how to flow nitrogen through the system.
   • It was agreed that the standoff between boards would be 1 cm.
5. Temperature compensation (Jack)
   • Has been considering a passive scheme suggested by Fernando
   • Asked requirements on the variation allowed for gain. Elton said that +/-5% should be used, which is what Hamamatsu will provide with their devices.
   • It is likely that 2 divider sets will be required, one for 5 deg and one for 20 deg C. Switching between modes will be via electronic switch. The actual gain may be different between these two settings, but the uniformity kept.
6. Preamp-summing (Fernando)
   • Received files from Chuck, but needs to upgrade software to read them in (almost complete). The files will contain boundaries for laying out the electronics.
   • Hamamatsu board (with summed output) ready to ship out next week
   • Boards with 16-cell readout for testing should be ready soon and can be made available to Yi/Carl and USM.
   • Specification list must include: dynamic range, linearity
7. Next meeting
   • It was decided to meet weekly and Thu afternoon at 3:00 pm was a good time. Next meeting will be on Jan 27.