PrimEx Experience with HYCAL

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PrimEx Experience with HYCAL

• David Lawrence, JLab
• Apr. 21, 2005

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PrimEx A Precision Measurement of the ?o
Lifetime via the Primakoff Effect
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Primex Setup
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?o Event
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PrimEx Run 2004

• Ran from Sept. 29 - Nov. 24 (commisioning done 10
  days prior)
• Took data using 3 different fixed targets C, Sn,
  and Pb
• 400k ?os recorded

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HYCAL1152 PbWO4 576 Pb-Glass
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HYCAL TransporterRange1m in both x and
yResolution2mm
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HYCAL Temperature Control
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Light Monitoring System

• 31 NICHIA super bright blue LEDs (470nm, 40ns
  pulse)
• 6 integrating sphere
• Bundle of 2000 Si-glass fiber optics

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Light Monitoring System
LED Bundle Chosen over Nitrogen Laser because of

• Higher reliability (lower maintenance)
• Better stability - 2 over 1 week, 0.5 over
  5min
• Lower cost
• Lower noise introduced to environment

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Light Monitoring System

• System was extremely valuable in testing and
  comissioning HYCAL without beam
• Online, LMS was used mainly for macro monitoring
  (all channels reporting with no major gain
  shifts)
• Not yet implemented in offline HYCAL analysis

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Online Calibration
HYCAL was scanned through the photon beam in a
snake-like fashion such that every detector was
centered on the beamline. Automated program
collected data from DAQ and adjusted HV for each
detector.
I. Larin, ITEP
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Resolution of HYCAL Elements
3 Fastbus crates (Which detectors were plugged
into the noisy one?)
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?o Mass Resolution
Single cluster energy resolution 1.2
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Still To Do

• Finalize calibration- Utilize LMS data-
  Alignment studies using Compton events-
  Incorporate Lead-glass
• Extract ?o Yield from ? distribution
• Calculate photon flux