Feb 24, 2011 Readout

Teleconference Time: 10:30 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
• 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. Update on simulation with summed cells (Andrei and Irina)
2. Update Document Control at JLab with signed copies of QA (UofR), QC/QA (IU), and procedures for signoff of non-conforming items (Elton and Tim).
3. Plot the angular distribution of pi0 and etas (Elton)

Tentative Agenda

1. Announcements
2. Review of Action Items
3. USM update
4. SiPM update
   1. First Article testing
5. Simulations
6. Electronics/cooling
7. Geometry and light guides
   1. Monitoring system light injection: Media:athens_led_fiber.pdf

Minutes

Attending:Elton, Beni, John, Tim, Yi, David, Eugene (Jlab); Zisis (UofR); Will (USM)

1. Announcements
2. Review of Action Items
3. USM update
   1. Box shell for testing is complete, including Cu cooling plate and holes for SiPMs
   2. Working on the response to JLab solicitation
      • Exchanges with Hamamatsu ongoing
      • Some concerns regarding risk of payment in FY12, but working through them
      • There is one 1000 piece delivery (the first) vs regular 500 piece deliveries which is under discussion with Hamamatsu
   3. Light guide (2 sets of 40) to JLab are in the plan. Jlab mentioned that delivery at the end of April meets our timeline.
   4. Alam has completed the design of the main SiPM testing board in 6 layers. Presently investigating based on input from Serguei whether this can be reduced to 4 layers. This would simplify fabrication and increase options for production.
4. SiPM update
   1. First Article testing (YI)
      • Test setup is proceeding well. Control software has been completed for readout of the Multi-Channel ADC and for measuring the IV curve. Sample tests have been completed.
      • The response of the SiPM amplifier board develops oscillations when many cells are plugged in. Carl and YI are working with Fernando to solve this problem.
      • Expect the test setup to be ready when the First Article units arrive in about a week.
5. Simulations
6. Electronics/cooling
7. Geometry and light guides
   1. Monitoring system light injection: Media:athens_led_fiber.pdf
      • Testing of double-ended readout. LED is glued to a scintillating fiber, which was inserted and glued into a small hole drilled into the light guide at a 15 degree angle (few mm deep).
      • The fiber effectively "collimates" the light to direct it toward the far pmt. The near pmt receives reflected light.
      • Ratio of Far/Near signals was determined to be 1.9.
      • Multiple optimizations can still be studied. Will suggested trying an angle closer to 0 degrees. Athens has determined that the LED can be mounted on wires that provide flexibility in positioning and aiming.
      • Eugene asked about placement in actual experiment. The picture on p. 2 shows the setup for a trapezoidal guide.
      • Will: Have any timing measurements been completed? No to date.
      • Beni inquired about the asymmetry in the ADC disctribution on p. 5. This may be due to multiple reflections and should be studied further.
      • Eugene noted that if only a small fraction of the (reflected) light is visible in near pmt, it might be quite sensitive to details of geometry and or positioning.
      • Zisis will summarize the work into a document for further feedback.