May 6, 2010 Readout

Teleconference Time: 11:00 a.m. EST

• ESNET and EVO session
• Phone in CC F326 is 757-269-6337
• Phone:
  • +1-800-377-8846 : US
  • +1-888-276-7715 : Canada
  • +1-302-709-8424 : International
  • then enter participant code: 77438230# (remember the "#"). Phone connection only upon request.

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. Fill out loan agreement for SiPM arrays at UofR (Elton).
3. Start a bulleted list of testing for the SiPMs (Serguey).
4. Distribution of p.e. corresponding to each sensor within the readout sum (Andrei).

Documents to Review

• File:SiPM contracting timeline v0.pdf
• GlueX-doc-1474 BCAL Dynamic Range from the Simulation with FLUKA

Tentative Agenda

1. Announcements
2. Review of Action Items
3. Update - USM
4. USM MOU/contract update (Elton)
5. Simulation runs
6. Geometry
7. SiPM Radiation Hardness Test (Yi)
8. SiPM - Testing Schedules
9. Light guides

Minutes

Attending: Will, Serguei, Alam (USM); George, Andrei (UofR); Elton, Chuck, Fernando, Beni, John, Yi

1. Announcements
2. Review of Action Items
3. USM MOU/contract update (Elton)
   • Reviewed timeline for SiPM procurement and contract with USM and was discussed.
4. Simulation runs
   • Andrei presented number of p.e. for 2x2 cm2 segments at 2.5 GeV at 12 deg. and center of readout segment.
   • Fernando: For the gain adjustment will need min and max for both upstream and downstream readouts
   • Beni: Based on the plots, we might want to consider summing 2, 2 and 6 instead of 3, 3 and 4. [Other arrangements should be considered in this optimization]
   • Eugene: What PDE is assumed? Andrei: The numbers use the QE for the Hamamatsu pmt of 18%. To obtain numbers hitting the SiPMs, we should adjust for response and light guide efficiency.
   • Cosmic-ray measurements to determine response of module to particles is underway.
5. Update - USM
   1. Light Guides
      • Straight tapered Light guide produced at USM. 3.75deg angle included. Surface quality is being checked.
      • After pliching would like to attach to baby Cal and measure light transmission.
   2. SiPMs
      • Test setup is under fabrication to test gain and dark current of 16 SiPMs at fixed temperatures between T=5-25 deg in DeltaT=5 deg steps.
      • Will went through a slide presentation prepared by Alam Toro showing the test setup
      • John: Are the cable connections between arrays and preamps a problem for the test? (they will be outside the light-tight temp-stabilized box.
      • Goal is to measure response to blue (495 nm) LED system. Dark current to be measured in between LED pulses.
      • Considering option for injecting test pulses onto electronics board. Several layers of the board will be devoted to ground planes to help shielding.
      • USM does not have any arrays. It is presently working with single 3x3 mm2 Hamamatsu SiPMs.
      • Side project includes using Zecotek 3x3 mm2 SiPMs for NA61. Measurements of this setup can be made available if it is of interest. The units have high pixel count (10^4/mm2), but low gain ~ 10^3 - 10^5.
6. Geometry
   • Elton asked if STP files have been successfully transfered back and forth between JLab and USM. Procedures are in place but full circle has not been completed.
7. SiPM Radiation Hardness Test (Yi)
   • After a 2 week cooldown in the Hall A labyrinth, they have been transfered to a location in the ARC for further testing.
   • Dark rate has decreased for both units (Hamamatus from 200 -> 135 microA, SensL from 1600->1100 micro A).
   • The measured change in amplitude could be (in part) attributed to radiation damage of the LED. However, the measured ratio of Hamamatu/SensL is not constant, which would be the case if only the LED was affected.
   • SiPMs will be continued to be monitored for recovery. The room temperature in the ARC is about 1.5 deg higher than in Hall A.
   • All documentation has been updated on the wiki page.
8. Other/ Fernando passed on a couple of items from Carl, who was unable to attend:
   • Werner Boeglin has received one array for testing the start counter
   • Hamamatsu advertises the 2x2 sub-array used in our 4x4 arrays as a standard catalog item now, and is available for sale.