Difference between revisions of "CDC algo tuning"
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#Event pedestal is mean of 100 samples ending at trigger time | #Event pedestal is mean of 100 samples ending at trigger time | ||
#Find hit threshold crossing | #Find hit threshold crossing | ||
− | #Step back <pedlead> points to find new pedestal | + | #Step back <pedlead> points to find new local pedestal |
#Search forward to find high threshold crossing | #Search forward to find high threshold crossing | ||
#Search backward to find low threshold crossing | #Search backward to find low threshold crossing | ||
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|} | |} | ||
+ | #Event pedestal is mean of 4 samples ending at trigger time | ||
+ | |||
+ | {| border="0" cellpadding="2" | ||
+ | |+ Both thresholds found using upsampled data; for timing, used low threshold xing only, with interpolation; 4 sample event pedestal | ||
+ | |[[Image:cdc_run_31942_track127f_np16_thr_5_1.png|thumb|x200px|Thresholds 5-1 pedlead 16 tz 7 tfix 1000]] | ||
+ | |} | ||
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#Use the 3rd sample (or mean of 3rd & 4th samples) before hit threshold as local pedestal | #Use the 3rd sample (or mean of 3rd & 4th samples) before hit threshold as local pedestal | ||
#Try reverting to one threshold crossing instead of the extrapolation - only slight increase to res width | #Try reverting to one threshold crossing instead of the extrapolation - only slight increase to res width | ||
− | #Try something easier for event pedestal - mean of 4 samples immediately before trigger | + | #Try something easier for event pedestal - mean of 4 samples immediately before trigger - this might be an improvement |
Revision as of 22:14, 4 December 2013
Using prototype data from CDC_50_50 (run 31942) with offline analysis
50/50 Ar/CO2 and cosmics, 2100V, prototype horizontal
Original code, many samples upsampled
- Event pedestal is mean of 100 samples ending at trigger time
- Find hit threshold crossing
- Step back <pedlead> points to find new local pedestal
- Search forward to find high threshold crossing
- Search backward to find low threshold crossing
- Project through both thresholds to find pedestal crossing time
- Event pedestal is mean of 4 samples ending at trigger time
Fewer samples upsampled
- Event pedestal is mean of 100 samples ending at trigger time
- Find hit threshold crossing
- Upsample region around threshold crossing, with threshold crossing sample in set position
- Step back <pedlead> points to find new pedestal
- Search forward to find high threshold crossing
- Search backward to find low threshold crossing
- Project through both thresholds to find pedestal crossing time
Ideas
- Check whether interpolating threshold xings makes any difference - no, not if extrapolating through thresholds to pedestal.
- Use the 3rd sample (or mean of 3rd & 4th samples) before hit threshold as local pedestal
- Try reverting to one threshold crossing instead of the extrapolation - only slight increase to res width
- Try something easier for event pedestal - mean of 4 samples immediately before trigger - this might be an improvement