CDC prototype more on timing

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Revision as of 14:37, 21 October 2011 by Nsjarvis (Talk | contribs)

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Current analysis code procedure:

  1. Calculate s.d. of pedestal for first 100 samples, 100 events, save for later use (sigma)

For each event...

  1. Calculate mean pedestal over 100 samples ending 10 samples before the trigger time (every 4th of these samples also works)
  2. Search forward for sample x where adc value > high threshold n1 sigma
  3. Step back p samples to sample p-x, take adc value of sample p-x to be local pedestal value
  4. Subtract local pedestal value from a number (10+p) of samples starting at sample x-(p+5) to the LE algo for interpolation
  5. Search through interpolated samples, start with last sample (highest adc value) search backwards until adc value < low threshold n2 sigma
  6. Calculate time where interpolated samples cross n2 sigma, and add to time of sample p-x, this is the estimated drift time.

Interpolated adc values (z) using different values for p (local pedestal lead time ahead of first/high threshold crossing) for high threshold of 5 sigma. Sample p-x has z=0, 5 interpolated values per sample, all events for ch17 (central straw) included (no tracking)

p=2
p=3
p=4
p=5

High threshold 4 sigma

4 sigma, p=2
4 sigma, p=3

High threshold 6 sigma

6 sigma, p=2
6 sigma, p=3