FCal Energy Scale Predictions J.Rutherfoord 9 June 2003

9 June 2003J. Rutherfoord2 Overview  The signal path  Signal pulses  Calibration pulses  The inputs and uncertanities  Summary predictions

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9 June 2003J. Rutherfoord4 Points of Reflection At interconnect (but neglect this) Off distributed Ohmic resistance of cable At coupling capacitor At transformer (but neglect this except for sick channels) At vacuum and pedestal cables At imperfect matching of preamp input impedance to cable At many other smaller (negligible?) locations

9 June 2003J. Rutherfoord5 Calib PulserPreampShaperPipelineGainOffsetADC

9 June 2003J. Rutherfoord6 Signal Limits Pipeline limits signal size (2 nd lobe) Switch from Shaper High Gain to Medium Gain At 130, 260, and 300 GeV respectively for FCal1, FCal2, and FCal3

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9 June 2003J. Rutherfoord8 Triangle shape In principle, many things modify the shape of the triangle pulse. But none are significant. The significant parameters are initial current the drift time

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9 June 2003J. Rutherfoord12 10  H (1.8  H) 50  1.53  A/CalDAC out + Injection R 695  14 Channels in all; 4 shown preamp cable in … Calibration Pulser System

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9 June 2003J. Rutherfoord15 Courtesy of Adam and Petr

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9 June 2003J. Rutherfoord17 Table of FCal Signal Parameters

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9 June 2003J. Rutherfoord20 Summary Prediction Signal (on the electron scale ) and noise, both at High Gain Signal Noise (ADC Counts/GeV) (ADC Counts) FCal FCal FCal