Beam Test Meeting Mon. May. 07, 2012

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  1. Planning for down time on Wednesday
    • Remove pair spectrometer prototype from Hall (current in 60% position)
    • Move Hall A prototype from 35% to 60% position
    • Move Bcal prototype from 22% to 35% position
    • Move Fcal prototype from 5% to 22% position
  2. Preliminary look at pulse heights and times (Elton)
  3. What gains do we want to run at?
    • Gain Ratio (from Andrei's plot): Vbr=0.9/Vbr=1.2 = 1800/2500 = 0.72
    • Maximum ADC from downstream ch2 R491/R498 = 3300/4000 = 0.83
  4. FADC range from Run 484: Vbr=1.2V (Andrei)
  5. Bcal data to be taken
    • TDC threshold scan
    • Vover=1.2 V, 4 files 80k each, nominal TDC threshold
    • Vover=0.9 V, 4 files 80k each, nominal TDC threshold
    • Vover=1.2 V, 4 files 80k each, 1/2 TDC threshold
    • Vover=0.9 V, 4 files 80k each, 1/2 TDC threshold
    • Vover=1.2 V, 4 files 80k each, 1/4 TDC threshold
    • Vover=0.9 V, 4 files 80k each, 1/4 TDC threshold
  6. Considerations in choosing the SiPM operating voltage (Notes by Elton)
    • PDE increases with overbias (favors 1.2 V)
    • Noise increases with overbias (favors 0.9 V)
    • Higher voltage decreases sensitivity to absolute bias voltage setting (favors 1.2 V)
    • Gain increases with overbias, relaxing the electronic gain requirements (favors 1.2 V)


Minutes

FCAL

- time extraction mode still broken, hope to fix soon

- data taken at 7 degrees lower than nominal alignment

BCAL

- see above and logbook for more details

- data taking at 20 degree point complete

- will fix upstream electronics during beam studies on Wednesday

Overall

- will slide all detectors down 1 energy position on Wednesday

- FCAL to 22.8 %, BCAL to 35 %, Hall A to 50 %, pair spectrometer out