Jan 27, 2011 SiPM Electrical and Cooling

Background information

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

Action Items from previous meetings

1. Develop a specification sheet for the readout electrical and cooling system (Elton)
2. Run his cooling model simulation for the situation when the electronics was turned off (Jim)
3. Develop goals for mechanical prototype (Chuck and Jim)

Tentative Agenda

1. Announcements
2. Schedule and reporting (Elton)
3. First article testing (Carl and Yi)
4. Mechanical cooling (Jim)
5. Temperature compensation (Jack)
6. Preamp-summing (Fernando)
7. Discussion

Minutes

Attendees: Jim, Carl, Jack, Fernando, Yi, Elton

1. Announcements
2. Schedule and reporting (Elton)
   1. Reviewed EVMS reporting xcel file with small updates
   2. Reviewed preliminary specification sheet.
      • Signal cables are RG58 with LEMO connectors. (Elton suggested RG174 pigtails to bring out to patch panel)
      • Power connectors not defined. However, each wedge would have +/- 5 V(?) and 4 bias leads, so about 6 inputs.
3. First article testing (Carl and Yi)
   • Carl has checked more recent Hamamatsu arrays. A 3x3 cell has dark rate ~ 1 MHz, compared to 4-5MHz on previous samples
   • New PC is being installed for testing in ARC 628
   • The front end for testing is labview, but John is providing a backend interface to KAMAX for ease of displays.
   • Yi is beginning to automate the system. He will be ordering electronics to accomplish this.
4. Mechanical cooling (Jim)
   • Gluex-doc-1663 of calculations for removing the heat from the electronic boards using air flow.
   • This results in very high flow rates: 1600 cfm for 1deg C temp rise of air, and 80 cmf for 20 deg C temp rise of air.
   • Concept for prototype box described.
5. Temperature compensation (Jack)
   • Calculations of passive compensation system are very promising, indicating that system can be kept within a +/-2% gain change. This system should dissipate about 0.8 W (20mW/ch).
6. Cooling Mechanical (Suggestion by Fernando)
   • A new idea was floated by Fernando, which is very appealing:
   • Interchange the location of the temp comp and pream/sum boards, i.e. the temp comp board would but up against the cooling plate
   • Feed the SiPM pins though the cooling plate and the temp comp board to the preamp/sum board.
   • Place a layer of Sil pad between the preamp/sum board and a metal heat spreader. The heat spreader could be used to collect the dissipated heat and this could be cooled with a secondary cooling loop or simply cooled by conduction to the outside.
   • Jim will take a look at this and review possibilities.
7. Preamp-summing (Fernando)
   • Requested updated table of Npe for dynamic range
   • Gain of 16-cell preamp board for testing has a gain of about 64
8. Discussion
   • Elton requested slides from Jack, Jim and Fernando so they could be included into his presentation at the next GlueX-Collaboration-Jan-2011.