Difference between revisions of "Feb 10, 2011 SiPM Electrical and Cooling"
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# Announcements | # Announcements |
Revision as of 18:46, 11 February 2011
Contents
Background information
- Files for discussion
- Hall D BCAL Readout Mechanical Concept (Jim Fochtman)
Action Items from previous meetings
-
Run his cooling model simulation for the situation when the electronics was turned off (Jim) - Update Npe numbers on dynamic range table to include effect of attenuation length (Elton)
Tentative Agenda
- Announcements
- Schedule, reporting, and manpower (Elton)
- First article testing (Carl and Yi)
- Mechanical cooling (Jim)
- Temperature compensation (Jack)
- Preamp-summing (Fernando)
- Discussion
Minutes
Attendees: Elton, Fernando, Tim, Chuck, Jim, Carl, Yi
- Announcements
- Schedule, reporting, and manpower (Elton)
- New ETC change request indicates we will need about 2 more people on this project, mostly in electrical sector.
- Fernando and Jack should check whether additional persons are required. Fernando said that Chris Stanislav will assist with the board design. He is in the process of hiring another tech.
- First article testing (Carl and Yi)
- Carl is installing a backup DAQ.
- Carl will work with Fernando to reduce ringing on signals from the new amplifier board.
- John McKisson will help with any histograming requirements.
- Yi has ordered parts and all have been received
- He has written all the drivers for the devices, and is now working on integration.
- The test setup should be ready in about a week and shakedown will take another week. It should be ready when the first article pieces arrive first week in March.
- Mechanical cooling (Jim)
- Considerable discussion on the present mechanical design. The goal is to have a volume enclosure starting from the end of the Bcal to the preamp/sum board. With this design the heat of the board can be vented to the outside.
- Connectors are suggested for the end of the preamp/sum board to allow for gas tightness
- Most of the design up to the electronic boards is fixed and can be ordered.
- Temperature compensation (Jack) Jack is in Baltimore, but sent the following updates
- I have a solution for 3 - 7 C that will keep divider errors within 6% with nominal 1% (EIA-96) resistor values. The error can stay within about 4% if the trim resistors are selected from the 0.5% values (EIA-192).
- This solution appears to be also very close for operation at 18 - 22 C but has an offset. This could be compensated for by modifying the Vsupply when operating at the 20 C range.
- This approach works for any arbitrary Vbr for a SiPM but imposes a requirement that we group the SiPMs so that the values of the Vbr are within 0.2 V or better. Error drops within 5% if the binning is by 0.1V Vbr steps. I think that may be difficult. Grouping the SiPM devices that share similar Vbr *may* not allow this simpler solution given the number of devices and the number of bias supplies.
- I'm now looking more closely at a slightly more complex passive solution that would still require binning the devices by Vbr but could widen the range to perhaps 0.25V or 0.4V. This solution uses a pre-trim divider network to widen the allowable Vsupply. It adds two more resistors to each passive divider (all EIA-96).
- The total power consumption would again rise - but only slightly. The trade-off there is power consumption for immunity to count rate gain shifts.
- Preamp-summing (Fernando)
- Fernando suggested a mini-PC board that could connect signal lines from the SiPM connector onto a single line for connection to the electronic boards.
- This suggestion was well-received, as it would greatly reduce the size of cutouts in the boards, as well as additional connectors.
- Discussion