Minutes 060808

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Attendees: Matt (Indiana), Dan Sober (CU), George, Rafael (Regina), Zisis (Calgary)

  1. Business Arising
    • None.
  2. Detector Setup/Mechanics
    • Indiana: Matt presented the results of tests for cross talk among the light guides for the BCAL. The results were quite conclusive that cross talk was minimal and of no consequence, even though a fairly luminous LED was used to illuminate each read-out cell. The results were more or less expected based on the SciFi emission angles but nevertheless resolved the question with actual data.
    • Regina: George reported that all paperwork for the shipments had been done and that the cosmic ray calibration counters (two) for the BCAL are being made locally.
  3. Hall-B Tasks:
    • Nobody from JLab was on the call today.
  4. Monte Carlo:
    • Rafael showed the results of the simulations of electron-positron pair trajectories created by photon conversion in all the beam line elements, the profile monitors and the veto counters upstream of the BCAL. The number of events hitting the BCAL is very small, less than 2%. Among those, the majority are e+-e- pairs entering the BCAL and generated just upstream in the BPM and veto counters and they carry the same energy signature and trajectory as the original tagged photon that created them. They are indistinguishable from the original photon and are therefore good events. The small fraction that results in only one charged particle entering the BCAL have deposited energies much smaller than the valid events and are easily rejected based on total energy spectra. These simulations clearly showed that such backgrounds will not affect the quality of the data and the conclusions.
  5. Any other business
    • None.

Action Items

  1. BPM, Veto: David and Elliott will work on making this a functioning system.
  2. Light Leak: Elton will look for black tedlar material (or equivalent).
  3. Cosmics counters: Regina will provide.
  4. Mu metal foil: Eric will measure the field inside the insert and mu-metal by making a single mu-metal shield out of the sheet that Regina has ordered. We will measure the field in the Alcove as a function of BCAL position.
  5. Tagger, Trigger, Cables: The trigger logic and timing details are being continously refined. The fast core cable is pending.
  6. Data storage/Silo Request: David and Zisis will deal with this offline.
  7. Online Macros/MC Data steam/MC Validation & Binning: David and Zisis will work on these offline. Zisis will provide requirements for ROOT trees.
  8. Beam Request: Elton, David and Zisis will carry this discussion offline.
  9. Safety, COOP: We will piggy-back on standard H-B documentation with the addition of our oqn equipment.
  10. Run Plan: Regina will draft this and the calibration procedure with cosmics and beam.