Dec 06, 2010 Calibration/Monitoring

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Revision as of 18:29, 7 December 2010 by Zisis (Talk | contribs) (Minutes)

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Teleconference Time: 09:10 CST (Regina) / 10:10 EST / 17:10 GMT+2 (Athens)

  • ESNET preferred, EVO as a backup

Background information

Tentative Agenda

  1. Go over goals/objectives of Monitoring system and review past discussions.
  2. Discuss LED-fibre-light guide concept.
  3. Summarize info, prepare recommendations and discuss it in Working Group to reach conclusion and proceed with Athens Construction MOU.


Attendees: Christina (Athens), Elton (JLab), Zisis (Regina)

  1. System Goals: (see Item 2 October 26 and Item 2 November 23 -- backup info in Nov 30 minutes)
    1. SiPM dead/alive (or on/off) check: Agreed that it is needed but by itself not enough to justify a system.
    2. Time check/offset: Agreed to have and together with previous point starts supporting the use of a system.
    3. Relative gain check: Agreed that this is a main/important goal. Degradation should be monitored continuously (on the scale of hours).
    4. Linearity check: There is no conclusion on this issue and it should be discussed further. Such a test should be done on the bench when evaluating the performance of the SiPMs prior to installation. We need to consider the number of pixels that would need to fail and likely scenarios to see whether such a check is needed. Considering the dynamic range (400) even a few LEDs beaming together would only test a small part of this range.
    5. Temperature stability: Agreed that this is most likely not an issue. Athens LEDs at max light (stable region) show 0.5%/ oC variation. Hall D will have ~1 oC stability at any given point, over time. Inside the solenoid we are planning for ±2 oC, so a 4 oC range for the stability, after thermal equilibrium is reached. SiPM boards will have temp sensors and are only ~10cm away from LED board (when mounted on light guide). SiPM feedback system on temp aims at better than 0.1 oC stability.