Apr 14, 2011 SiPM Electrical and Cooling

Action Items from previous meetings

1. Check impact of material at low end of readout, both in the tubes for cooling fluid but also in the Cu cooling plate. Need to check effect on particle trajectories.

Tentative Agenda

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
4. SiPM testing (Carl and Yi)
5. Mechanical cooling (Jim)
   • Review status of drawings for prototype (Chuck)
6. Temperature compensation (Jack)
7. Preamp-summing (Fernando)
   • Will present a discussion of cabling and grounding next week.
8. Discussion of production testing

Minutes

Attending: Elton, John, Carl, Yi, Jim, Chris, Eugene, Chuck

1. Announcements
   • There will be no meeting next week
2. Action Items
3. Schedule, reporting, and manpower (Elton)
   • Updated EVMS
4. SiPM testing (Carl and Yi)
   • Completed testing of all 80 SiPM units
   • Need to recheck some samples. One had low PDE measured at relatively high ambient temperature, has been retested and seems ok but final analysis not complete. A second has one noisy cell, but this is consistent with the Hamamatsu data.
   • Will start preparing a report
   • Also will retest one of the original arrays to verify present setup reproduces previous rates.
   • Yi is preparing two samples to expose to neutron source
   • Comment by Carl: pin connections are delicate and handling requires care. Need a tool to straighten pins
5. Mechanical cooling (Jim)
   • Updated drawings using rubber bellows to provide light tight seal, contain dry gas and mate with insulation
   • Found some chip pullers. Ordered one and may be able to modify for our application.
   • Single-PM testing equipment designed. Need to verify dimensions with Jack
   • Review status of drawings for prototype (Chuck)
   • Chuck will complete detailing drawings tomorrow and send out for fabrication.
   • Parts for the mechanical prototype have been ordered, and expected by the end of May.
6. Temperature compensation (Jack)
   • Proposed various schemes to connect rows of arrays to the five bias voltages.
   • Simplest scheme might not work with Fernando's bias distribution and needs to be checked.
   • Jack will provide the design to Chris, so he can incorporate the bias control on his board.
7. Preamp-summing (Chris)
   • U-board has been ordered, as well as supporting parts. Needs to add Jack's circuitry when complete.
   • Then go out for prototype board.
8. Discussion of light guide geometry as four identical columns which are phi-symmetric
   • Initial response was positive. Will need to layout in more detail to verify that it all fits.
   • Prospects for casting a unit of 10 guides might be challenging, but Jim will get feedback from companies.