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
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Latest approach to hit finding is as follows:
  
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# Find a hit channel
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# Find a hit channel and event pedestal
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## Calculate mean pedestal P_{m} & s.d. (sigma) for first 100 samples in 100 events (trigger is approx sample 200)
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## Calculate mean pedestal P<sub>m</sub> & s.d. (&sigma;) for first 100 samples in 100 events (trigger is approx sample 200)
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## Set a threshold T_{p} (eg 3.5 sigma) for further investigation, eg P_{m} + T_{p} , select events & channels where adc value exceeds this  
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## Set a threshold T<sub>p</sub> (eg 3.5 &sigma;) for further investigation, eg P<sub>m</sub> + T<sub>p</sub> , select events & channels where adc value exceeds this  
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## Calculate event pedestal P_{e} as mean of samples 90 to 190 in current event
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## Calculate event pedestal P<sub>evt</sub> as mean of samples 90 to 190 in current event
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## Select events where adc value goes over high threshold T_{h1} + P_{e} (T_{h1} ~ 5sigma)   
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## Select events where adc value goes over high threshold T<sub>h1</sub> + P<sub>evt</sub> (T<sub>h1</sub> ~ 5sigma)   
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# Find time
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# Upsample data from samples 150 to 350 (max drift time + trigger time is approx sample 290)
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# Find high threshold time and new local pedestal
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# Search forward to find point x1 where data goes above a not quite so high threshold T_{h2} + P_{e}  where T_{h2} ~ 4sigma
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## Upsample data from samples 150 to 350 (max drift time + trigger time is approx sample 290)
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# Find a local pedestal a number of upsampled points (eg 15) before x1
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## 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 &sigma;
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# Search backward from x1 to find point x2 where data goes below second not quite so high threshold T_{h2} + P_{e} where T_{h2} ~ 4sigma
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## 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)
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# Find a local pedestal a number of upsampled points (eg 15) before x1
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# Find low threshold time and new local pedestal
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## 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> ~ &sigma;

Revision as of 15:20, 20 March 2012

Latest approach to hit finding is as follows:

  1. Find a hit channel and event pedestal
    1. Calculate mean pedestal Pm & s.d. (σ) for first 100 samples in 100 events (trigger is approx sample 200)
    2. Set a threshold Tp (eg 3.5 σ) for further investigation, eg Pm + Tp , select events & channels where adc value exceeds this
    3. Calculate event pedestal Pevt as mean of samples 90 to 190 in current event
    4. Select events where adc value goes over high threshold Th1 + Pevt (Th1 ~ 5sigma)
  1. Find high threshold time and new local pedestal
    1. Upsample data from samples 150 to 350 (max drift time + trigger time is approx sample 290)
    2. Search forward to find point x1 where data goes above a not quite so high threshold Th2 + P_{e} where Th2 ~ 4 σ
    3. Find a local pedestal Ploc as adc value at Np upsampled points before x1 (eg Np=15)
  1. Find low threshold time and new local pedestal
    1. Search backward from x1 to find point x2 where data goes below low threshold Th2 + Ploc where Th2 ~ σ
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