Jan 25, 2011 Calibration/Monitoring
Teleconference Time: 09:00 CST (Regina) / 10:00 EST / 17:00 GMT+2 (Athens)
- ESNET preferred, EVO as a backup
- Monitoring R&D issues for the relative gain calibration and monitoring system for the calorimeters and possibly other detector systems.
- Calibration Specifications Table for BCAL, FCAL, TOF and START
- Calibration and Monitoring System Meetings Previous minutes
- Why was the dynamic range of the APD tested over 20-450? Where there intrinsic limitations? Can it be extended to form a ratio of 400?
- Can George calculate the % deviation from linearity on his plot?
- Can George verify that the two-setting operation (low bias for near, high bias for far SiPM flashing) is feasible?
- What is the approximate power dissipation for each board? (Just LPM since LPCM will be further away).
- Zisis will bounce another idea for the one-setting operation mode.
- USM should be contacted to send more LGs to Athens (and eventually Regina).
- Discuss Action Items.
- Review goals/objectives of Monitoring system.
- Presentation to CALWG and Collaboration Meeting.
Attendees: Christina (Athens), Elton (JLab), Zisis (Regina)
- Action Items.
- Dynamic range was that of the APD (10-450). Measurements need to be repeated for SiPMs.
- % deviation from linearity: pending.
- Two-setting operation (low bias for near, high bias for far SiPM flashing) is feasible.
- LPM board power dissipation: micro-Watt. See George V's notes: Media:RadiatedPower.pdf
- Zisis presented Anderi's idea for the one-setting operation mode: glue LED to a short (1-2 cm long) SCSF-78MJ fibre, and glue fibre to LG at a suitable angle. Fibre's numerical aperture acts as a collimator, directing most of the light to the far end. This may reduce the ratio of near to far to an acceptable level. Regina will conduct quick measurements to determine if this method is feasible.
- Zisis will contact USM to send more LGs to Athens (and eventually Regina). Elton will look for a spare SiPM plus board to send to Athens.
- Other issues:
- Price quote for prototype system (180 LPM boards and 6 LPCM boards was euro 8000.
- Absolute timing offset will be impossible to determine. Check of path and TDC units will be accomplished.
- FADC current algorithm (max and integral determination) was discussed briefly. A different algorithm can be pursued and programmed if needed.
- Optical cross talk needs to be evaluated, for any method chosen.
- Our discussions will be summarized in the Thursday January 27 CALWG readout meeting.
- Zisis will adjust the Collaboration meetings agenda to have Monitoring first at 14:30 on Feb 3. Elton will provide a summary talk. Christina and Zisis will assist in the preparation of the talk.