Jan 24, 2011 Calibration/Monitoring

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Teleconference Time: 09:00 CST (Regina) / 10:00 EST / 17:00 GMT+2 (Athens)

  • ESNET preferred, EVO as a backup

Background information

Tentative Agenda

  1. Review goals/objectives of Monitoring system and past discussions.
  2. George Voulgaris' slides: Media:AnswersaboutLED.pdf
  3. Discuss Matt's suggestion: groove in light guides, radial fibres. (sent as email)
  4. Summarize info, prepare recommendations and discuss it in Working Group to reach conclusion and proceed with Athens Construction MOU (decision by May 2011).


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

  1. Review goals/objectives and background information:
    • Revised ETC request timetable for the BCAL/FCAL Monitoring Project will indicate May 2011 - April 2012. There is a reasonably firm plan for the FCAL and the same needs to be achieved for the BCAL by May or sooner. This will aid in getting the contract in place, money flowing to Athens and will help with crew morale.
    • Athens could use some funds right away to purchase additional boards and go to the next phase which comprises a large-scale evaluation as well as light-leaking into adjacent cells. USM should be contacted to get more light guides sent to Athens.
    • Dynamic range of SiPMs is planned to be 400. Andrei's plots show at least 200, so there is some safety margin built in.
  2. George Voulgaris' slides. The information looks good. Some questions:
    1. Why was the dynamic range of the APD tested over 20-450? Can it be extended to form a ratio of 400?
    2. Can George calculate the % deviation from linearity on his plot?
    3. Can George verify that the two-setting operation (low bias for near, high bias for far SiPM flashing) is feasible?
    4. What is the power dissipation for each board? (Just LPM since LPCM will be further away).
    • Christina will report back on these questions.
  3. Discuss Matt's idea:
    • The committee found the idea interesting. There are challenges that would need to be evaluated experimentally, such as getting light out of the fibre, machining, coupling. The implementation looks difficult and most likely not achievable considering the above timetable. The committee decided to go back to the nominal plan and identify serious weaknesses. There appear to be none, as long as the tw0-setting operation can be implemented. Zisis will bring up another idea towards the one-setting operation in tomorrow's meeting.
  4. Summarize info:
    • Meeting adjourned until tomorrow, owing to the use of the JLab video conference room.

Action Items

  1. USM should be contacted for shipping additional LGs to Athens (and to Regina eventually).
  2. Christina will collect answers to questions in item 2.
  3. Zisis will bring up a new idea for the one-setting method.