Detector Characteristics

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Detector Characteristics
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Detector Details
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Vital Statistics

• Overall detector area 6.4 cm by 6.4 cm
• Wafer thickness 400 mm
• Silicon n-type substrate, p-type strips
• Large substrate resistivity 5-8 kW
• Number of strips 320
• Strip pitch 194 mm
• Strip width 50 mm
• AC coupled strip readout

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Some Considerations in Estimating Energy from TOT

• Detector Energy deposited gt Charge Q in
  detector
• Landau Distribution of deposited energy
• Shot noise
• Preamplifier and Front End Electronics
• Threshold Calibration
• Charge Saturation plateau in TOT vs. Input
  charge response
• Controller and Readout gt TOT
• Estimated charge Q gt Estimated particle energy

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Leakage Current

• Possible source of detector noise
• Minimized with care. Usually a small noise
  source
• Shot noise. Mainly affects long shaping time.
• Temperature dependence
• Leakage current doubles for each 7C rise in
  detector temperature
• Bias voltage dependence
• Illustrated on following chart

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I-V Characteristics
HKM Factory Data, Detector 312. Factory Data for
other 3 detectors similar. 25C
SCIPP Data, Apr. 25, 2001 24C
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Energy Deposition
Comparison of Landau distribution (theoretical
line) with ToT data from GLAST
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Two MIP Events
Comparison of theoretical and observed energy
deposition for possibility of 2 tracks passing
through the same strip