June 3, 2010 Readout

Teleconference Time: 11:00 a.m. EST

• ESNET and EVO session
• Phone in CC F326 is 757-269-6337
• Phone:
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Items for followup from previous meeting

1. Serguei agreed to send out a testing proposal for comments, including preliminary circuit designs and list of available equipment at USM for reference.
2. Start a bulleted list of testing for the SiPMs (Serguey).
3. Will to find out if there is any feedback from USM on terms and conditions from our procurement package.

Documents to Review

• GlueX-doc-1474 BCAL Dynamic Range from the Simulation with FLUKA
• GlueX-doc-1432 Trapezoidal guides for the light collection for SiPMs (Fig 22)

Tentative Agenda

1. Announcements
2. Review of Action Items
3. Update - USM
   1. Alam's presentation from last week - update on USM MPPC test setup (Alam)
   2. MPPC Measurements - time stability of current, effect of UPS (Sergey)
   3. Comments on MOU (Will/Sergey)
   4. Progress on light guide prototyping (Sergey)
4. USM MOU/contract update (Elton)
5. Simulation runs
6. Cosmic-ray setup at UofR
7. Geometry [| Latest readout assy]
8. SiPM Radiation Hardness Test (Update from Yi)
   • I updated the recovery curves with more data i collected, no major change
   • Hall A is still not ready for beam, hopefully by the end of this week they can take beam;
   • Carl needs a little bit more time to give me the 1x1 mm SiPM and start to test the dark rates of 3x3 SiPMs, hopefully early next week.
9. SiPM - Test Electronics (Fernando)
10. Light guides

Minutes

Attending: Pedro, Elton, Tim, Beni, Eugene, Chuck, John, Fernando (Jlab); Zisis, Andrei (UofR); Will, Serguei, Alam (USM).

1. Announcements
   • Responses to SiPM RFPs received, technical committee to meet next week.
   • Elton will be absent, so Zisis will run the next meeting,
2. Review of Action Items
3. Update - USM
   1. Alam's presentation from last week - update on USM MPPC test setup (Alam)
      • Test stand design outlined with much discussion, some notes follow:
      • Test setup for testing 16 SiPMs simulataneously. Design under review, especially to simplify insertion and removal of sensors to be tested.
      • Measurement of 16 expected to take 8 hours, with 2-3 hours of setup/take down time.
      • Separate setup would be used to test all SiPMs on their corresponding electronics board to be used in experiment.
      • Capability for testing at several different temperature, nominally 5, 10, 15, 20 and 25 deg C. Planning to purchase chiller to control temperature. At the lower temperatures, condensation will need to be controlled. Fernando noted that production testing may not require multiple temperatures. Will states that the plan is to prepare for exhaustive testing, a reduced list may evolve.
      • John: Concern with mechanical problems with multiple insertion and removals of SiPMs into sockets. Fernando to suggest options for robust mechanical and electrical connections of SiPMs to boards during testing and production.
      • Serguei requested JLab send him the thermal properties of the SiPM casing. Fernando volunteered.
      • Eugene: Why so many fibers? Could replace with single source and illuminate all 16 units. [Concerns with fibers include issues of uniform illumination and potentially saturating light into small region of SiPM]. Serguei indicates that light to SiPM may be adjusted by changing the distance of fiber to sensor. Mechanical design might/should include options for calibration of light intensity from each fiber.
      • Status: Design advancing with feedback at each stage. Accumunating equipment for setup; purchased VME crates with modules; chiller will be ordered soon; start making mechanical parts for box in a couple of weeks.
      • Zisis: Suggestion to collect this information on the wiki for ease of presenting information.
   2. MPPC Measurements - time stability of current, effect of UPS (Sergey)
      • Problem with draw current in current setup, traced to UPS powering of SiPMs when main power was off.
      • Zisis: UofR invested in an isolation transformer, which has been very effective at reducing noise.
   3. Comments on MOU (Will/Sergey). Suggested a change of date for readiness for testing sensors from August to December, in agreement with the schedule. Change ok'd by JLab.
   4. Progress on light guide prototyping (Sergey). Two guides are ready and will be shipped to Athens. Four additional guides will be made and sent to Regina. Inaki is working on various techniques for light guide production. A laser cutting machine used for a test, hoping that polishing can be avoided. Imperfections in the guides produced by the small CNC machine was due to software mistake and should be able to be corrected.
4. USM MOU/contract update (Elton)
5. Simulation runs
6. Cosmic-ray setup at UofR
   • Lab space being reclaimed after an interruption
   • All materials ordered.
   • Goal is to do some deliberate "gap" measurements to check with light guide calculations. Then proceed with Npe measurements.
7. Geometry [| Latest readout assy]
   • Latest geometry presented with trapezoidal guides glued to module and gap between guide and sensor.
   • Decision on geometry for sensor not finalized, but will be kept for base mechanical design.
8. SiPM Radiation Hardness Test (Update from Yi)
   • I updated the recovery curves with more data i collected, no major change
   • Hall A is still not ready for beam, hopefully by the end of this week they can take beam;
   • Carl needs a little bit more time to give me the 1x1 mm SiPM and start to test the dark rates of 3x3 SiPMs, hopefully early next week.
9. SiPM - Test Electronics (Fernando)
   • PC boards for 1x1 and 3x3 mm2 units should arrive this week, tested next week so they can be used for tests in Hall A.
   • Zisis: Asked about radiation damage to preamp boards. Fernando: No degradation seen so far, nor is it expected because the front-end FET should be radiation resistant.
   • Zisis request: consider positioning radiation monitor as close to sensor as possible, as radiation "pockets" could occur in the hall. According to Eugene the neutron fluxes should be relatively uniform in this part of the hall.