Feb 17, 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. Update Npe numbers on dynamic range table to include effect of attenuation length (Elton)
2. Finalize drawings for defined parts and start ordering mechanical components (Chuck)
3. Check whether additional electrical tech/design personnel is needed to assist on this project. (Fernando and Jack)

Tentative Agenda

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

Minutes

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

1. Announcements
2. Schedule, reporting, and manpower (Elton)
   • Updated EVMS schedule. Fernando has updated manpower estimates
3. First article testing (Carl and Yi)
   • All equipment has arrived
   • Fernando has updated amp circuit to eliminate ringing on output
   • Yi has DAQ and control programing well underway. Operating at 1KHz
   • Integrating voltage control and temperature settings
   • Next will work on ROOT programs for fitting
4. Mechanical integration (Chuck)
   • Drawings are being prepared. Expect completion by Mar 1
5. Mechanical cooling (Jim)
   • Introduced a new idea of a "C" mini-board to deliver bias and sum the 16 inputs from the SiPM.
   • Considerable discussion on this subject, but the concept was accepted.
   • Improvements to the concept include: a) Change pins connections to electronic board with 3 coax cables. b) Change thermal paste for Silicon pads c) Thermistor connection to heat shield on back side.
6. Temperature compensation (Jack)
   • Carefully selecting 0.5% resistors for R2, will keep variations within 2.8% at 5deg C and less than 5% at 20 deg C.
   • Dark (leakage) current of SiPM will impact set points. Currently use 10microA of dark current for SiPM array, and the circuit draws 300 microA. If dark current increases significantly, this may impact variation in outputs. Note: The project design is to keep dark rate (i.e. current) increase to less than a factor of 5.
   • These currents are likely to be ok at 5 deg. At 20 deg the 5% may be exceeded, but should be able to be brought back into range by adjusting bias.
   • We decided we should keep the power consumption of the board at its current level below 1 W.
   • But... need to check on current draw during beam conditions.
7. Preamp-summing (Fernando)
   • As per discussion last week, it appears that the amp/sum electronics can fit on the top side of the board, which allows room for bias on the bottom side. This will allow to reduce the number of boards from 2 to 1.
8. Discussion