Difference between revisions of "CDC prototype more on timing"
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#Search forward for sample x where adc value > high threshold n1 sigma | #Search forward for sample x where adc value > high threshold n1 sigma | ||
#Step back p samples to sample p-x, take adc value of sample p-x to be local pedestal value | #Step back p samples to sample p-x, take adc value of sample p-x to be local pedestal value | ||
| − | #Subtract local pedestal value from a number (10+p) of samples starting at sample x-(p+5) to the LE algo for | + | #Subtract local pedestal value from a number (10+p) of samples starting at sample x-(p+5) to the LE algo for unsampling |
| − | #Search through | + | #Search through unsampled data, start with last sample (highest adc value) search backwards until adc value < low threshold n2 sigma |
| − | #Calculate time where interpolated | + | #Calculate time where interpolated unsampled data cross n2 sigma, and add to time of sample p-x, this is the estimated drift time. |
| − | + | ||
| − | + | Unsampled adc values (z) using different values for p (local pedestal lead time ahead of first/high threshold crossing) for high threshold of 5 sigma. | |
| − | + | 5 unsampled values per 8ns sample, all events for ch17 (central straw) included (no tracking) | |
{| border="0" cellpadding="2" | {| border="0" cellpadding="2" | ||
|width="450pt"| | |width="450pt"| | ||
Revision as of 09:44, 24 October 2011
Current analysis code procedure:
- Calculate s.d. of pedestal for first 100 samples, 100 events, save for later use (sigma)
For each event...
- Calculate mean pedestal over 100 samples ending 10 samples before the trigger time (every 4th of these samples also works)
- Search forward for sample x where adc value > high threshold n1 sigma
- Step back p samples to sample p-x, take adc value of sample p-x to be local pedestal value
- Subtract local pedestal value from a number (10+p) of samples starting at sample x-(p+5) to the LE algo for unsampling
- Search through unsampled data, start with last sample (highest adc value) search backwards until adc value < low threshold n2 sigma
- Calculate time where interpolated unsampled data cross n2 sigma, and add to time of sample p-x, this is the estimated drift time.
Unsampled adc values (z) using different values for p (local pedestal lead time ahead of first/high threshold crossing) for high threshold of 5 sigma. 5 unsampled values per 8ns sample, all events for ch17 (central straw) included (no tracking)
High threshold 4 sigma
High threshold 6 sigma
