Mar 10, 2011 SiPM Electrical and Cooling

References

• Files for discussion
• Hall D BCAL Readout Mechanical Concept (Jim Fochtman)
• Dynamic Range (See section 6 under simulations)

Action Items from previous meetings

1. Provide thermistor data sheet to Jim (Jack)
2. Get cable specs to Jim (Fernando)
3. Send "U" board to Fernando once finished (Jim)

Tentative Agenda

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
4. First article testing (Carl and Yi)
5. Mechanical cooling (Jim)
   • Review status of drawings for prototype (Chuck)
6. Temperature compensation (Jack)
7. Preamp-summing (Fernando)
8. Discussion

Minutes

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

1. Announcements
2. Action Items
   • All completed
3. Schedule, reporting, and manpower (Elton)
   • Drawings for mechanical FA completed
4. Mechanical cooling (Jim)
   • Model and drawings reviewed for prototype
   • Discussion of cables to the outside. Fernando mentioned that the cables from the patch panel to the electronics will be RG58 with Lemo connectors on the Bcal end. Connection inside the box will be from Lemo bulkhead to MMCX connectors.
   • Review status of drawings for prototype (Chuck)
   • Drawings for prototype are all ready except for the cooling board and this one is close. Should be completed tomorrow. Materials will be ordered next week
   • Fernando will have a dummy board made with resistors and connections to a power supply for heating test
5. Monitoring system
   • Chuck made a sketch of the Athens LED board to show how it might fit into the arrangement of light guides.
   • Elton mentioned that the circuit should allow for daisy chaining the power and trigger pulse.
   • Fernando said that the original controller board had a USB connection and this one should be replaced with a more practical protocol for the full detector.
6. First article testing (Carl and Yi)
   • Data for the first two samples was shown. Tests to date look very good. The noise is a factor of 4 lower than original test samples.
   • Digital power supply (computer controlled) is limited to 72 V, so the tests are being conducted with an analog PS which goes up to 120V. (Note the mean suggested voltage for the new samples ranges from 71.5 to 72.9 V).
   • Will investigate whether a similar digital supply can be obtained with higher voltage capability.
7. Temperature compensation (Jack)
   • Based on the data sent from Hamamatsu for the first article samples, Jack laid out a scheme for adjustment of bias voltages to each individual SiPMs. This can be accomplished with 4 voltage settings, and 3 trim resistors (each) for Rs and R2 on his board. This keeps all gains within 3% of their nominal setting.
8. Preamp-summing (Fernando)
   • Suggested that we should start the purchase of power supplies for the SiPMs, because the process is expected take some time.
9. Discussion