Apr 5, 2011 Readout

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Teleconference Time: 11:00 a.m. EST

  • ESNET 8542553 and EVO session
  • JLab Phone: in CC F326 is 757-269-6337 (usual room)
  • JLab Phone in CC L207 is 757-269-7084
  • Phone in the Regina Videoconference Suite is 306-585-4204
  • Athens Phone: in Christina's office is 011-30-210-727-6947
  • Phone:
    • +1-866-740-1260 : US and Canada
    • +1-303-248-0285 : International
    • then use participant code: 3421244# (the # is needed when using the phone)
    • OR from www.readytalk.com type access code 3421244 into "join a meeting" without the # (you need java plugin)

Items for followup from previous meeting

  1. Check if connections for cooling fluid can be bent radially outward to minimize affect on photons in the gap. Yes. Simulations of impact needed.
  2. Need to get a firm number for the power dissipation in the monitoring control board (in case it is placed inside the housing box)

Documents to Review

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. USM update
  4. SiPM update
  5. Electrical/cooling (Elton)
  6. Geometry and light guides
  7. Simulations


Attending: Elton, David, Yi, John, Eugene (JLab); Will, Serguei (USM); Zisis, Andrei (UofR); Christina (Athens).

Tentative Agenda

  1. Announcements
    • DIS Conference next week at JLab; tour of Hall D next Wednesday
  2. Review of Action Items
  3. USM update
    1. Received two of the "big" electronic boards (6 layers) for testing SiPMs. They are in the process of populating the boards
    2. SiPM sample sent from Jlab is still in customs.
      • Alam has fabricated a board with 16 fast amplifiers. Should be completed in a couple of days
      • Eugene: What is the rise time of the amplifier? Serguei: 4-5 ns for a 3x3 mm sensor
    3. Light guides
      • Guides for Athens have been completed, but are still uncut and unpolished
      • Guides for UofR next
    4. Discussions with Hamamatsu continue, although no direct reply since last e-mail
      • Considering signing a contract early to avoid penalties due to currency rate changes
  4. SiPM update
    1. Yi: Carl has tested 60 samples to date
      • Found one sample with anomalous cross talk (gain and PDE normal)
      • Evaluating options for production testing: Could readout cells in groups of 4 to save electronics and check p.e. widths to evaluate uniformity.
      • Serguei: Have we checked the cross talk between cells in the array? Yi: No, but we should do that.
      • Elton: How difficult would it be for JLab to copy the USM production test setup? Will: Unclear until the setup is verified to work. Serguei estimates it will take about one month to check the system.
      • Yi: How does USM intend to measure PDE and gain?
        • Serguei: Two test setups are being constructed 1. production, where every sensor is exposed to a standard light source. 2. small setup, measure PDE accurately by comparing response to light injected from fibers in a bundle that also illuminate a calibrated reference PMT.
        • Yi noted that our fit to extract the PDE and gain takes quite a long time and is CPU intensive.
    2. Serguei: Experimenting with a light source from "BrilLanCe" crystal from St. Gobain
      • Light from response to annihilation photons from a positron source.
      • Crystal deltaE/E ~ 12%. Crystal is 25 mm diameter and 25mm long.
      • PMT signal has rise time of 15 ns and pulse length of 100 ns.
    3. Regina Preliminary Tests of Hamamatsu prototype Media:ReginaLED-SiPMScan.pdf
      • Using a computer controlled platter to align a fiber guiding light from an LED to a single cell.
      • Using Hamamatsu array from original batch
      • Recorded response on an oscilloscope of all 16 cells.
      • Initial results show that response from cells is fairly uniform and reproducible. Work is onlging.
  5. Electrical/cooling (Elton)
    • Progress continues on the mechanical setup. Drawings for prototype is complete. We have a cost estimate and fabrication is under evaluation
    • Fernando has completed the schematics for the preamp/summing board. Chris (Stanislav) is starting to route the board.
  6. Geometry and light guides
  7. Simulations
    • There was some discussion of some of the simulation results, but studies are ongoing.
    • David has checked out the version that Andrei is using and at a first glance obtains results consistent with what Andrei showed last time.