Jan 13, 2011 Readout

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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:
    • +1-800-377-8846 : 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. Collect this information of testing (including goals and setup) on the wiki for ease of presenting information. (USM)
  2. Resolution including summing SiPMs (IU) Update today and ongoing
  3. Detailed schedule for testing at USM (Elton and Will). In progress
  4. George to send Elton information regarding the laser head so a new one can be ordered. PR submitted for replacement. Shipping documents in preparation.
  5. JLab to ship a SiPM Array to USM. Electronics and sensor to be shipped in Jan. Estimated completion in two weeks.

Documents to Review

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. Update - USM
    • SiPM test station (Alam)
    • Light guide fabrication (Iñaki)
  4. SiPM update
    • Preparations for testing
    • Regina preparations
  5. Simulations
    • Granularity Dan
  6. Electronics/cooling (Fernando)
  7. Geometry and light guides


Attending: Iñaki, Alam, Serguei, Will (USM); Beni, Elton, Jim Fochtman, Tim, Chuck, Yi, Fernando, Eugene (JLab); Andrei (UofR); Matt, Dan (IU)

  1. Announcements
    • USM has hired a new full-time technician to work in their lab.
  2. Review of Action Items
  3. Update - USM
    1. SiPM test station (Alam)
      • MPPC test facility expanding
      • Two types of preamplifiers have been designed. Type 1 with opamp, 23 boards built expected to have about 60,000 electrons input noise. Type 2 with single components expected to have 4,000 to 5,000 electrons input noise. The first type is expected to meet the needs for the SiPMs
      • Tests of gain for Type 1 preamplifiers have been completed.
    2. Light guide fabrication (Iñaki)
      • Starting prototype production of light guides.
      • Initial work showed two issues to address: fabrication time (33 hours/guide), and surface quality.
      • The time has been improved by machining two guides simultaneously and optimizing operation (down to 8 hours/ guide).
      • This work is using the small prototype machines. A larger machine that can be used for production, is expected at the end of the month. The programing of the larger machine should be the same.
      • Polishing: Irregularities in the surface quality of the first guides produced has been improved with polishing. Photos of polished guides looked good, but difficult to assess quantitatively.
      • Serguei sent the properties of the light guide material from CERN stock they are using as the base material.
  4. SiPM update
    • Preparations for testing
    • Regina preparations
  5. Simulations
    1. Granularity Dan
      • Dan presented preliminary information on the resolution of the BCAL depending on various groupings of cells. Two main configurations: outer cells 2x2 vs. 1x4; inner cells (3+3) vs (2+4)
      • Very little differences for the two configurations in the outer layers. Andrei inquired about looking at the rms vs. the fitted sigmas. Matt mentioned that the distributions themselves could be made available.
      • Some small improvement of the (3+3) configuration compared to the (2+4). Eugene inquired about the trend at very low energies where resolution seems to improve (unphysical). This is not quit understood, but seems to be systematic between the two configurations.
      • Still to be studied is the z-resolution, which comes from timing. Will suggested one should look at the timing directly.
      • Beni: Perhaps should consider looking at other particles besides photons. In that case the granularity might have different impact on parameters
      • Eugene and Matt: To make a decision on granularity one should also look at the efficiency of reconstruction (not just resolution). Another consideration was the impact of dynamic range on these measurements.
  6. Electronics/cooling (Fernando)
    • Components and boards received for 16-channel preamplifiers. They will be ready in about 2 weeks.
    • Summing readout to send to Hamamatsu should be ready next week. We have an RMA# for shipment.
  7. Mechanical and light guides
    • Light guide drawings have been updated on the portal at GlueX-doc-1642
    • Jim Fochtman is developing a mechanical cooling strategy for the Bcal readout. There was some discussion of some concepts after the meeting proper, which will presented at a later time.