Feb 24, 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. Check current draw of SiPMs during beam conditions (Yi and Carl)
2. Provide thermistor data sheet to Jim (Jack)
3. Get cable specs to Jim (Fernando)

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, Jim, Carl, Yi, Chuck, Tim, John, Elton, Eugene

1. Announcements
2. Schedule, reporting, and manpower (Elton)
   • No updates
3. First article testing (Carl and Yi)
   1. Ringing on the 16-cell preamp board. Not expected to be a problem for the first article testing.
      • apparent when more than 4 channels are fired simultaneously
      • due to very long cables attached to each cell, but not due to reflections or grounding
      • Fernando has updated the feedback look for the production preamp as well
      • Yi: concern that this may broaden pedestal, but expected not to be a problem for a sufficiently wide gate.
      • Yi: concern that ringing will behave differently for signals and dark noise
   2. Labview programs completed
      • DAQ multi-channel QDC taking data at 2 KHz
      • VI curve scan automated. Cycle time limited by settling time of about 5 s.
      • The web page has been updated with test results
      • Working on producing a ROOT file with summary histograms
4. Mechanical cooling (Jim)
   • Went over latest version of mechanical drawings. Much discussion, but basic concept remains
   • Jim would like access to one of the thermistor signals. Jack said that the thermistors for bias should not be used, but additional thermistors can be installed for use with the mechanical system
5. Temperature compensation (Jack)
6. Preamp-summing (Fernando)
   • Fernando presented slides of signals and simulation of the preamp/sum circuits
7. Discussion