Feb 4, 2015 BCAL Commissioning

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Meeting Time: 3:00 p.m. Eastern

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  • JLab Phone: in CC F326 is 757-269-6460 (usual room)
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Resources

Tentative Agenda

  1. Announcements
  2. Action Items
  3. What do we need to do before the spring run?
    • Verify fixes with LED runs
    • Humidity settings
    • Attempt +5 C?
    • Check channel efficiencies
    • Verify pi0 statistics, estimate amount required
  4. Parameters
    • DAQ thresholds (Nominal: 105, or 5 above pedestal)
    • Bias voltage setting (Nominal: 1.2V above breakdown)
    • Temperature setting (Chiller = 64 deg F, 18 deg C)
    • N_sa and N_sb (N_sa=55 , N_sb=5)
    • Effective velocity
    • Time offsets
    • Time-walk corrections
  5. LED pulser runs
    • Verify fixes to hardware channels
    • Check humidity readback/settings
    • Create configuration that takes data through the TS for concurrent north and south running
    • Automate and enhance scripts to analyze the pulser runs.
  6. Cosmic-Ray runs
    • Settings for cosmic runs: shall we match settings for April running?
    • Can we check efficiencies for a given DAQ threshold?
    • How to effectively use data triggered on the BCAL?
    • How to calibrate timing?
    • What simulations are needed to support all calibration?
  7. Any other business

Minutes

Attendees: Elton, Will, Noemi, Mark (JLab); Zisis, Tegan, Ahmed, Andrei (UofR)

  1. Announcements
    • Running this spring: accelerator will start mid-Fed, Tagger Hall possible lock down on Feb. 20. Elton will schedule a walk-through on that date. Regina has bunched up all its shifts (36-38) in April.
    • Beam schedule: opportunistic physics in the fall Accelerator needs to go from 10 to 12 GeV, necessitating 2x more power. The new scheme will deliver 11 GeV to the three halls, and 12 GeV to Hall D, using 250 MHz at the injector (500 MHz to some halls, but 250 MHz to GlueX).
  2. Action Items
  3. What do we need to do before the spring run?
    • Verify fixes with LED runs
    • Humidity settings
    • Attempt +5 C? Repairs connected to the high dew point in one BCAL sector revealed a miscabled sensor and holes at the bottom of the detector that were plugged. The up side humidity went from 23->16% already (same day) but no change on the down side. Will continue to monitor.
    • Check channel efficiencies
    • Verify pi0 statistics, estimate amount required. Will M. is continuing with the analysis and is expecting results soon.
  4. Parameters
    • DAQ thresholds. DAQ system not fully functional; CODA update. Not clear if we will have TS and all crates or just TI trigger with 6 crates at a time, for the upcoming cosmics runs.
    • Bias voltage setting: in the fall we ran at 1.2 V overbias. We need to rethink running at 0.9-1.0 V (our decision from last year) where we gain in S/N. Also, our gain appears to be to high anyway (400 MeV pi0).
    • N_sa and N_sb: their sum is 55 x 4ns = 220 ns; wide but captures the longest-tail pulse. Probably leave as is.
    • Effective velocity: currently using 17 cm/ns from Regina measurements with SiPMs and cosmics on a prototype module. Extract it from data. Will need tracking and timing info.
    • Time offsets: we have rough detector-wide factor. Need channel-by-channel offsets.
    • Time-walk corrections: not urgent.
  5. LED pulser runs
    • Verify fixes to hardware channels
    • Check humidity readback/settings
    • Create configuration that takes data through the TS for concurrent north and south running
    • Automate and enhance scripts to analyze the pulser runs.
  6. Cosmic-Ray runs
    • Settings for cosmic runs: shall we match settings for April running? In the fall we took a lot of cosmics at +18 C and some at +12C. Threshold was at 5 counts above, which had been lowered from 10 counts.
    • Can we check efficiencies for a given DAQ threshold?
    • How to effectively use data triggered on the BCAL?
    • How to calibrate timing?
    • What simulations are needed to support all calibration?
  7. Any other business

Action Items

  1. Take LED runs to check system (Elton and Noemi)
  2. Investigate pedestal parameters for different temperatures (Tegan)
  3. Analyze runs at different overbias for efficiency/noise (?)
  4. Think about how best to use BCAL-triggered runs to study calibrations (Andrei and Zisis)
  5. Investigate how to check efficiency vs DAQ thresholds (Elton)
  6. Determine effective velocity for each channel (George?)
  7. Determine time-walk corrections (George?)
  8. Determine time offsets (?)
  9. Implement David's dark hits code.