May 10, 2011 SiPM Electrical and Cooling

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Action Items from previous meetings

  1. Determine if swapped bias pins was accidental or in design (Chris)
  2. Develop front and back views of jumper sheets. Also get latest version of drawings (Jack)
  3. Check into AC units based on Peltier coolers for SiPM production tests (Fernando)
  4. Assemble the second SiPM puller to send to USM (Scot)
  5. Order and assemble a third SiPM puller as a backup for JLab (Jim and Scot)
  6. Setup clean tents in the ESB for gluing light guides. Prepare a plan for production testing. (Elton, Tom)

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Schedule, reporting, and manpower (Elton)
  4. Beam test experience (Elton)
    • Connections to RTD. Wires are very fragile in the field. We broke a connection when we replaced the downstream module, but were able to replace with new connector. Yesterday during the move, we lost the temperature reading to the upstream plate. For production, these connections will be internal and connectors will be more robust.
    • Installation and space for monitoring control board. Space was very limited for this board with the standoffs to adjust to the configuration for the mini-Bcal. Again the cabling will be internal and robust connectors for disconnection will be used for the production modules.
    • We had a major reconfiguration of detectors under the tagger. The PS prototype was removed, the Hall A prototype moved downstream to take its place, the mini-Bcal moved to the previous Hall A location and the Fcal prototype was brought down from the alcove into the vacated spot by the Bcal.
    • The new improved upstream electronics board was replaced on the mini-Bcal, but we have not yet had a chance to take a look at the data.
    • A major goal from this run is to establish the operating point for the SiPMs. It is likely that we will reduce the overall gain by about 2-3. Part of this may be by setting the bias of the SiPM, the remainder in the electronic gain of the preamplifier.
  5. SiPM production testing (everyone)
    • Bobby has started production testing of the SiPMs. One box (40 SiPMs) has been tested.
    • One of the three boards was noisy and removed for Chris to take a look at it. He found some samtec cables with connection problems. Should be fixed.
  6. Mechanical assembly (Scot)
    • The SiPM extractor for USM was assembled and given to Hayk to take back to Chile.
  7. Mechanical (Jim)
    • A new set of mechanical components, with all the new modifications is on order.
  8. Mechanical drawings (Chuck)
  9. Temperature compensation (Jack)
    • Has reviewed the data from USM. Based on the sequence of numbering, it appears that Hamamatsu had a failed wafer. The performance of the SiPM numbers following the gap have improved performance, suggesting that they fixed some production issues. The additional data looks consistent with previous distributions with no major outliers.
    • Decisions on the gain need to be made before final components are selected.
  10. Preamp-summing (Fernando and Chris)
    • Moving ahead on quotes for the U-boards.
    • Found that the UFL cables from different vendors have different reliability. Have decided to select the vendor with soldered (instead of crimped) center pins, which makes the assembly more reliable.
    • Purchasing of final resistors will need to wait decision from beamtest on operating point and gain of preamplifier.
    • Need to update the transition board with lemo cables so that we have a complete set of all components for the readout.
    • Will order 2-3 boards with modifications based on feedback from beamtest. These will be tested on the bench before going out for full production.
    • Note on labeling (upstream/downstream): The labeling internal to the modules will be the same for all assemblies. A different mask for the cover plate will be made for upstream and downstream so that cabling will match the mirror image.
  11. Light guide gluing setup
    • Light guides. Have requested that USM give us a schedule for delivery of complete sets of light guides (instead of deliveries of guides of a single type). Expect response tomorrow.
    • Bcal LED boards and cabling / control boards. We have made a request to Athens for their schedule on Bcal LED boards, so that we can integrate them into our gluing schedule.
    • Wrapping for light guides. Jim will develop the tooling/procedures for obtaining the patters for making the wrapping from tedlar. Wrapping will likely be done in house.

Minutes

Attending:

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