Sep 3, 2009 Calorimetry

Meeting will be dedicated to Calibration and Monitoring

Teleconference Time: 11:00 a.m. EST

• ESNET and EVO session
• Phone:
  • +1-800-377-8846 : US
  • +1-888-276-7715 : Canada
  • +1-302-709-8424 : International
  • then enter participant code: 77438230# (remember the "#"). Note: code changed 7/2/09

Items for followup from previous meeting(s)

1. Review calibration procedures. Use next meeting to review calibration and monitoring
2. Two components fit for fiber attenuation (Zisis)

Documents to Review

1. Link to Calibration-Monitoring page

Tentative Agenda - Meeting dedicated to calibration and monitoring

Focus on the primary issues and consider what changes are needed to the mechanical configuration.

1. Announcements
   • We anticipate receipt of SensL SiPMs by mid Sep, and Hamamatsu units first week of October
   • Bcal fabrication Readiness Review tentative date: Wed Oct 7.
2. Review of Action Items
3. Calibration/Monitoring Options (Christina) [1]
4. Calibration using pions/protons (Andrei/Irina) Media:pions.pdf
5. Calibration/Monitoring Requirements
   • Fcal
   • Bcal
   • Other systems
6. Collaboration Meeting Agenda
   • Times of talks need adjusting
   • Comments?
7. Quick updates
   • Fcal
   • Bcal
   • BCAL Readout - Lightguide simulation study
8. Other business

Minutes

Attendees:UofA: Christina, George V., IU: Matt, Ryan, Claire, UofR: Zisis, Geore, Andrei, Danny, USM: Alam, Will, JLab: Elton, Sasha, Beni, John, Tim, Eugene

1. Announcements
   • We anticipate receipt of SensL SiPMs by mid Sep, and Hamamatsu units first week of October
   • Bcal fabrication Readiness Review tentative date: Wed Oct 7.
2. Review of Action Items
3. Calibration/Monitoring Options (George V.)
4. Calibration/Monitoring Requirements
   1. Fcal
      • Main calibration will use pi0s. Claire has shown that 1 day can accumulate sufficient statistics for a 1% calibration.
      • Pulser system will simply need to monitor detector between pi0 calibrations. Will be used to balance pmts and checking for dead channels.
      • Question: What precision is required in the trigger for hardware gain matching of blocks?
      • Monitoring required at the 1% to carry calibration between pi0 runs
      • Sheet of plexiglass seems to be a good option for Fcal. Eugene: 10-100 times more rad hard than Pb glass. Elton: UVT acrylic has the least radiation resistance.
      • Intensity control over monitoring light intensity desirable.
      • Eugene: For LED solution: use groups to pulse many channels to minimize the number of light sources that need to be stabilized (e.g. with respect to temperature).
      • Tim: asked whether plexiglass system could be used to inject sufficient light for curing glass. The consensus was that it would not be able to deliver enough light to blocks.
      • Final thoughts Matt: Some consideration has been given to LED pulsing individual channels. This is not favored since the number of monitoring sources is as large as the number of Fcal channels, even if they are paired for redundancy and cross calibration.
   2. Calibration using pions/protons (Andrei/Irina)
      • Systematics are a great concern for this procedure. The back segments show no peak in the spectra and have low yield, so are very dependent on the tails of the hadronic showers, and therefore very dependent on the modeling of hadronic interactions.
      • Christina: Hadronic interactions have very poor resolution in the calorimeter, so these are not the ideal calibration sources.
   3. Other systems
5. Collaboration Meeting Agenda
   • Elton will increase times. Fcal could use reduced time.
6. BCAL Readout - Lightguide simulation study
   • Three efforts are ongoing: 1. full GEANT4 simulation, 2. Geometric ray tracing (discussed in today's talk), 3. Wavelength dependent absoption and reflection.
   • The geometrical ray-tracking for Pedro's configuration of light guides shows very high (geometric) transmission for inner segments, which recommends this geometry.
7. Other business