Jul 28, 2011 SiPM Electrical and Cooling

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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. Ongoing study by Beni

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Schedule, reporting, and manpower (Elton)
  4. SiPM testing (Carl and Yi)
  5. Mechanical (Jim)
  6. Mechanical drawings (Chuck)
  7. Geometry (Elton)
  8. Temperature compensation (Jack)
  9. Preamp-summing (Fernando)

Minutes

Attending: Jack, Chris, Jim, Eugene, Yi, John, Elton

  1. Announcements
  2. Action Items
  3. Schedule, reporting, and manpower (Elton)
    • No progress to report on EVMS
  4. SiPM testing (Carl and Yi)
    • Carl and Yi moved equipment to EEL 126 to setup for production testing. Nw computer, VME with v430 backplane, 7 V792 boards.
    • Discussed some previous experience running that many boards at once. Jack said that this was a triggering problem at high rates and should not be an issue for us
    • Everything is being assembled. Waiting for dry nitrogen: will likely use a dewar with dry ice to purge box and keep it dry.
  5. Mechanical (Jim)
    • Verified that #6 screws can be used for the support plate
    • Orders for RTD (resistance temp device) was placed to achieve readback accuracies of 0.15 deg at 0 deg C.
    • Samples of glue from Norland Industries for guide trials have been received. Elton mentioned that some of the prototype light guides can be used
    • Decided to change cooling plate from Cu to Al and glue the copper tube into the al plate. Will try this out on plates for SiPM production testing
    • The plate for production testing setup will be designed around Fernando's electronic board.
  6. Mechanical drawings (Chuck)
  7. Geometry (Elton)
    • Need updated light guide drawings to send out for procurement. Will talk to Chuck and Tim.
  8. Temperature compensation (Jack)
    • Tested bias circuit with no jumpers and not yet connected to array
    • Tests show circuit behaves as expected (deviations about 0.2% around 5deg) for 56mV/deg C. For the range 5-20 deg, 60mV/deg change seems to work better.
    • Next need to change configuration to different jumper settings and verify operation
    • Connect up to a SiPM array and check performance
    • Yi: Has the nonlinearity been checked? Not yet. Is the difference between 56 mV/deg and 60 mV/deg due to the components, or other reason? Will investigate
  9. Preamp-summing (Fernando)
    • Fernando has dramatically improved the rise time of the SiPM pulse from 15 down to 5 ns by adding four decoupling capacitors on the bias inputs directly on the U-board.
    • Elton showed the new circuit that Fernando had assembled, which will be used to test the timing characteristics.
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