Sep 6, 2011 Readout
From GlueXWiki
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)
Contents
Items for followup from previous meeting
-
List of information to be stored in the data base (USM) -
Check status of light guide production and polishing (USM)
Documents to Review
Tentative Agenda
- Announcements
- Review of Action Items
- Monitoring Update (Athens)
- Geometry of monitoring board (Elton)
- USM Update
- SiPM update
- Electrical/cooling (Elton)
- Geometry and light guides
- 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.)
- Announcements
- First 500 SiPM sensors from Hamamatsu arrived on Fri.
- Review of Action Items
- Monitoring Update (Athens)
- Geometry of monitoring board (Elton)
- USM Update
- Discussion of contents of database for USM MPPC testing, by Hayk Hakobyan
- Stage 1: microscope inspection
- Tim: record dimensions (thickness and width) of chips, compare to pattern
- 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.
- 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.
- Reminder of background information from Will's talk at the last collaboration meeting
- 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.
- Will: Obtain access to refurbished lab space this week, which may result in a couple of days interruption of daily activities.
- Light guides discussion (Iñaki)
- Finish guides for Athens by end of next week (20)
- 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.
- 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
- Simulations / segmentation (David)
- Summary of work presented to a limited audience last week
- 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.
- SiPM update
- 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.
- Geometry and light guides
- 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.