Difference between revisions of "CDC prototype more on timing 3"
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(Created page with "Latest approach to hit finding is as follows # Find a hit channel ## Calculate mean pedestal P_{m} & s.d. (sigma) for first 100 samples in 100 events (trigger is approx sample 2...") |
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− | Latest approach to hit finding is as follows | + | Latest approach to hit finding is as follows: |
− | # Find a hit channel | + | # Find a hit channel and event pedestal |
− | ## Calculate mean pedestal | + | ## Calculate mean pedestal P<sub>m</sub> & s.d. (σ) for first 100 samples in 100 events (trigger is approx sample 200) |
− | ## Set a threshold | + | ## Set a threshold T<sub>p</sub> (eg 3.5 σ) for further investigation, eg P<sub>m</sub> + T<sub>p</sub> , select events & channels where adc value exceeds this |
− | ## Calculate event pedestal | + | ## Calculate event pedestal P<sub>evt</sub> as mean of samples 90 to 190 in current event |
− | ## Select events where adc value goes over high threshold | + | ## Select events where adc value goes over high threshold T<sub>h1</sub> + P<sub>evt</sub> (T<sub>h1</sub> ~ 5sigma) |
− | # Find time | + | |
− | # Upsample data from samples 150 to 350 (max drift time + trigger time is approx sample 290) | + | # Find high threshold time and new local pedestal |
− | # Search forward to find point x1 where data goes above a not quite so high threshold | + | ## Upsample data from samples 150 to 350 (max drift time + trigger time is approx sample 290) |
− | # Find a local pedestal | + | ## Search forward to find point x1 where data goes above a not quite so high threshold T<sub>h2</sub> + P_{e} where T<sub>h2</sub> ~ 4 σ |
− | # Search backward from x1 to find point x2 where data goes below | + | ## Find a local pedestal P<sub>loc</sub> as adc value at N<sub>p</sub> upsampled points before x1 (eg N<sub>p</sub>=15) |
− | + | ||
+ | # Find low threshold time and new local pedestal | ||
+ | |||
+ | ## Search backward from x1 to find point x2 where data goes below low threshold T<sub>h2</sub> + P<sub>loc</sub> where T<sub>h2</sub> ~ σ |
Revision as of 15:20, 20 March 2012
Latest approach to hit finding is as follows:
- Find a hit channel and event pedestal
- Calculate mean pedestal Pm & s.d. (σ) for first 100 samples in 100 events (trigger is approx sample 200)
- Set a threshold Tp (eg 3.5 σ) for further investigation, eg Pm + Tp , select events & channels where adc value exceeds this
- Calculate event pedestal Pevt as mean of samples 90 to 190 in current event
- Select events where adc value goes over high threshold Th1 + Pevt (Th1 ~ 5sigma)
- Find high threshold time and new local pedestal
- Upsample data from samples 150 to 350 (max drift time + trigger time is approx sample 290)
- Search forward to find point x1 where data goes above a not quite so high threshold Th2 + P_{e} where Th2 ~ 4 σ
- Find a local pedestal Ploc as adc value at Np upsampled points before x1 (eg Np=15)
- Find low threshold time and new local pedestal
- Search backward from x1 to find point x2 where data goes below low threshold Th2 + Ploc where Th2 ~ σ