Feb 2, 2011 SiPM Electrical and Cooling

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Action Items from previous meetings

  1. Populate interface cards to the ADC (Chris)
  2. Complete 3 remaining boards for SiPM testing (Chris)
  3. Determine if swapped bias pins was accidental or in design (Chris)
  4. Modify design so that the samtek/ADC transition board the locking mechanism works (Chris)
  5. Provide cost information to Chris regarding the thermistor (Jack)
  6. Check to see if files sent from Athens can be read (Jim/Chris) Yes.

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Schedule, reporting, and manpower (Elton)
  4. SiPM production testing (everyone)
  5. Mechanical assembly (Scot)
  6. Mechanical (Jim)
  7. Mechanical drawings (Chuck)
  8. Temperature compensation (Jack)
  9. Preamp-summing (Fernando/Chris)
  10. SiPM testing (Ivan)

Minutes

Attending: Chris, Jim, Ivan, Carl, Yi, Elton, Jack, Scot, Eugene

  1. Announcements
  2. Action Items
  3. Schedule, reporting, and manpower (Elton)
  4. SiPM production testing (everyone)
    1. Testing (Yi)
      • One SiPM tested to check performance. Several issues were found and fixed. Noise was generated by the lack of ground connection to the ribbon cable. Adaptor board does not seat completely due to interference with the latch. One board has been filed down and works adequately. A second board has been damaged, and will be returned to Chris for possible repair.
      • Following adaptations, distributions are somewhat wider than measured for the FA, but acceptable. Temperature is 23-24 deg C.
      • Control software is almost done. Automatic upload of data file to work disk is finished. Manual e-log entries are not implemented.
      • Pedestal levels are a problem. The coupling of SiPMs to the V792 module generates levels that are too positive and disturb the measured distributions. Changes of a 10 Ohm resistor to a 0.01 microF capacitor are made on a second board to check if they solve this problem.
    2. OSP (Carl)
      • OSP will be required for the test setup
      • Carl will generate a draft and pass on to Elton for comments.
      • We discussed various precautions including a) gloves b) grounding strap / anti-static prevention c) tool for extraction.
  5. Mechanical assembly (Scot)
    • Working with EH&S to be able to chemically polish the unpolished light guides.
    • Setup is essentially ready: oven, beaker, resting plate,
    • Awaiting feedback from safety.
    • Alternative option is to have guides hand polished at $32/hr.
    • New glue has been received and will be tried soon.
  6. Mechanical (Jim)
    • Scheme for wrapping light guides is in the works. Suggest to use Tedlar. There should be several scraps at the lab to check this out.
    • Pin fixture is underway.
    • Rework of the vacuum wand is ordered, and should be ready by the end of next week.
  7. Mechanical drawings (Chuck)
  8. Temperature compensation (Jack)
    • Thermistors are special order. Due to the reduced cost for large quantity decided to order 4200 (0.5 % tolerance) with 5-7 week delivery. Also order 100 with 5% tolerance for use in the mini-Bcal
  9. Preamp-summing (Fernando/Chris)
    • Wedge board and thermistor boards are in hand. Populating the boards will take a couple of weeks.
    • SiPM compact design boards should arrive next week and be populated in house
  10. SiPM testing (Ivan)
    • Waiting for EH&S to approve laser operation
    • Requires a second engineering control, but in the short term may be substituted with an administrative lock.
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