Sep 6, 2011 Readout

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. List of information to be stored in the data base (USM)
2. Check status of light guide production and polishing (USM)

Tentative Agenda

1. Announcements
2. Review of Action Items
3. Monitoring Update (Athens)
   • Geometry of monitoring board (Elton)
4. USM Update
   1. Discussion of contents of database for USM MPPC testing, by Hayk Hakobyan
   2. Reminder of background information from Will's talk at the last collaboration meeting
   3. Photos of new bigboards and daughterboards from Alam
   4. Discussion about lightguides?
5. SiPM update
6. Electrical/cooling (Elton)
7. Geometry and light guides
8. Simulations

Minutes

Attending: Ivan, David, Tim, Beni, Elton (Jlab); Alam, Iñaki, Hayk, Will (USM); Zisis, Andrei (UofR) Note: Several Athens collaborators tried to connect via EVO, but were not successfully patched in. (Later we found Jlab had internet and e-mail connectivity problems, so this may have been a factor.)

1. Announcements
   • First 500 SiPM sensors from Hamamatsu arrived on Fri.
2. Review of Action Items
3. Monitoring Update (Athens)
   • Geometry of monitoring board (Elton)
4. USM Update
   1. Discussion of contents of database for USM MPPC testing, by Hayk Hakobyan
   2. Stage 1: microscope inspection
      • Tim: record dimensions (thickness and width) of chips, compare to pattern
   3. Stage 2: PDE and pulse shape measurement (only 3 of 32)
      • Beni: Add operating voltage? Elton: We still need to determine the operating point for the SiPMs. In our latest timing measurements, voltages higher than those proposed by Hamamatsu give optimal timing resolution.
   4. Stage 3: Dark box measurements
      • Elton: Does the power supply deliver more than 73 V (some of our samples require higher operating voltage) ? Alam: Yes (200 V). Will increase voltage until 200 microA of current is reached.
      • Zisis: How to safeguard data from accidental deletion of overwrite? Will look into this.
      • Elton: How automatic is the data logging to the data base? Hayk: Most of the data is recorded automatically.
      • Will: Final mechanism for data transfer is still under discussion. One scheme had the low level driver write a file which could be read into a ROOT file for processing.
   5. Reminder of background information from Will's talk at the last collaboration meeting
   6. Photos of new bigboards and daughterboards from Alam
      • 3rd generation of big boards. To date only previous generation board tested. Do not expect large performance differences between this board and its predecessor.
      • Photos of 2 big boards, several daughter boards, and connector boards.
      • New boards were stuffed last week. Four daughter boards mounted but not tested yet.
   7. Will: Obtain access to refurbished lab space this week, which may result in a couple of days interruption of daily activities.
   8. Light guides discussion (Iñaki)
      • Finish guides for Athens (20), sending them by Sept 26.
      • JLab can use guides as soon as they are available for gluing tests
      • UofR: Does not require light guides till mid October due to other ongoing activities.
      • Schedule has been delayed to make changes to the larger machine that can handle larger volume.
      • Question about the 1% haze specification in light guide material: Elton: I thought this was a typical spec for UVT material. Could consider alternatives if it results in poor availability.
5. SiPM tests
   • Zisis: graduate student continues with SiPM tests using the 10 first article samples which we shipped. No results yet, but work in progress
6. Simulations / segmentation (David)
   1. Summary of work presented to a limited audience last week
   2. Comments by Andrei:
      • May wish to restrict the range of energies for the table, especially at 90 deg. Elton: the resolutions are given at specific energies (0.5 GeV and 1.0 GeV), not for the range of generated photons (flat in 0-2 GeV).
      • See if introducing systematic timing offsets between individual SiPMs leads to significant changes in the resolution (of summed channels): David: Will concentrate first on writing up what has been done, and then turn to this and other issues.
7. SiPM update
8. Electrical/cooling (Elton)
   • Fernando is investigating whether an additional layer will fit on the PC board
   • Drawings for mechanical parts that do not depend on decision of new layer are being prepared.
   • Tim: Should go ahead and get first articles for all boards to make sure they fit using best guess as to final decision on inner layer.
9. Geometry and light guides
10. Simulations
    • Dave presented summary of simulations of the timing resolution of different granularity schemes.
    • The 1-2-3-4 option results in better timing performance by 20-30% compared to the 3-3-4 option.