Difference between revisions of "Sep 2, 2008 Calorimetry"
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| Location of calibration input ||From front to monitor rad damage || || || | | Location of calibration input ||From front to monitor rad damage || || || | ||
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− | | Geometrical constraints || Approximately 90% of area available || || || | + | | Geometrical constraints || Approximately 90% of front 4x4 cm2 area available || || || |
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Revision as of 13:15, 2 September 2008
- Phone:
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- then enter participant code: 39527048# (remember the "#")
Contents
Items for followup from last meeting
- George: report on trip to Edmonton
- Estimates of pedestal width (electronic noise, etc.) for FM PMTs. The dark rate should be negligigle in this case.
- Resolution studies with up-to-date geometry (Blake) ONGOING
- Resolution studies with different segmentation for the outer section. - LOWER PRIORITY
- Add F100 rad hard glass to simulation. - Matt will do this
- Decision on Bcal sampling fraction needed by Sep. - Work by Stamatis (on vacation) will be summarized upon his return.
Documents to Review
- Please place documents here for review in advance of meeting
- Calibration-Monitoring
- Paul Smith's Fiber Pulser
Tentative Agenda
Note: This meeting will be dedicated to reviewing calibration issues. Other reports will be included as time permits.
- Announcements
- Review of Calibration Issues
- Athens update report: GlueX-doc-1092
- Reports
- Fiber Test Stand at JLAB (Beni)
- Fiber Tests at Regina (Kathryn)
- Updates
- FCAL
- BCAL
- Comments on the collaboration meeting. Suggestions from last meeting
- Any other business
Minutes
Attending: Athens: Christina, George, Pavlos; UofR: Zisis, George, Kathryn, Blake; JLab: Elton, Beni, Tim, Fernando; IU: Matt, Mijahlo, Claire Tareert; FIU: Werner.
Announcements
- Claire Tareert is a new research associate at IU. Welcome!
Review of Calibration Issues
- Athens update report: GlueX-doc-1092
- Christina went over the posted presentation
- First the laser option was presented
- APD used to monitor the absolute light from the laser, but noise pick up from the laser was a problem. Elton indicated that a full shield was necessary to shield the laser. Method for shielding similar laser can be found on the bottom of page 3 of Hall B CLAS-NOTE 91-002.
- The second LED option was presented.
- 2x1 cm2 boards with the LED and pulsing electronics have been made; 35 boards produced.
- The idea is to place the boards near each pmt to be calibrated, e.g. on the light guide of the SiPMs. George: could be placed on the tapered length of the guide.
- Fernando asked about the temperature dependence: it has not yet been measured.
- Control board (for about 30 LEDs) has been constructed and would be placed about 2-3 m away from the LED.
- Question about masking individual channels for firing? This would check (optical) cross talk between channels.
- The calibration system needs to have its requirements clearly defined. Each subsystem (Fcal, Bcal, Start counter) reviewed its requirements, but further refinement is necessary.
- Elton prepared the following table to clarify the requirements. We need to complete it to provide adequate feedback to Athens:
Characteristic | Fcal | Bcal | TOF | Start |
---|---|---|---|---|
Light uniformity channel-to-channel | ||||
Dynamic range of input (number of photoelectrons) | ||||
Requirement on absolute light input | none (PRIMEX might have) | |||
Time stability (one channel) | ||||
Location of calibration input | From front to monitor rad damage | |||
Geometrical constraints | Approximately 90% of front 4x4 cm2 area available |
Reports
- Fiber Test Stand at JLAB (Beni)
- Fiber Tests at Regina (Kathryn)