Dec 10, 2010 SiPM Electrical and Cooling

Background information

• Files for discussion

Tentative Agenda

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

Minutes

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

1. Review schedule and list of "deliverables"
   • Enclose 3D model
   • Light guide grating
   • SiPM mount
   • cooling plate
   • preamp/summing board
   • ADDED: Electronic heat removal (possibly heat plate)
   • temp feedback/ bias board
   • light covers
   • cable supports/layout
   • cooling tubes support/layout
   • mechanical support
2. First article testing (Carl)
   • Reviewed list of tests to be conducted for first article
   • Estimated time is 1.5 to 2 hours per unit (i.e. 120 - 160 hours of testing for 80 units). Note that nominal schedule has 1 month for accepting first article.
   • Yi: Automation using labview interfaces may help speed up testing.
   • Will continue discussion at meeting next week
3. Mechanical cooling (Jim)
   1. Issue with current plate and 4 mm tubing requires 80 psi with 4% pressure drop to equilize temperature.
   2. New concept with 3/8" od tubing uses 10 psi (nominal chiller output) with 0.1 psi pressure drop.
   3. New concept replaces SiPM mounting plate with PC board and SiPM pin connection via traces to a connector that mates with pre-amp/summing board.
   4. Fernando: Several issues with this new idea:
      • Primarcy concern: increased inductance of leads due to routing through board connector
      • SiPMs are soldered onto PC board, which makes replacing arrays difficult
      • Can do some tests to check impact of these changes on performance, but they are likely to be large
4. Temperature compensation (Jack)
   • Difficulty with design for continuous operation between 5 and 25 deg. Likely two settings will be required, one at 5 deg and one at 20 deg.
   • Carl: DeltaG/DeltaT is constant with temperature, so gradients are expected to be the same for the two settings.
   • Discussion of various design options. Current ideas lead to about 65 mW/channel or about 1 mA/ device at 70 V. Precision resistor consumes 45 mW. Off the self items are equivalent to 100 KOhms for $2/resistor. At 1 MOhm sell for $20/channel, reducing power consunmption.
   • Fernando to share previous design ideas with Jack for reference
5. Preamp-summing (Fernando)

Next Meeting

1. Will meet Christmas to continue discussion of First Article Testing. No optimal time is available. Proposal
   • Thursday at 4 pm, or Friday at 1:30 pm. Based on feedback, I will chose the day/time.