Difference between revisions of "CDC signal integration new"
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<div id="time_over_threshold"> | <div id="time_over_threshold"> | ||
− | Look at time over threshold... or rather, signal duration | + | Look at time over threshold... |
+ | |||
+ | Search back from end of sample window until ADC value rises above a threshold, tried 3sigma, 5sigma, 8sigma (sigma= pedestal std dev). The initial hit selection is on 5sigma so all events will pass this. | ||
+ | |||
+ | {| border="0" cellpadding="2" | ||
+ | |+Time over threshold 3sigma | ||
+ | |[[Image:run_31809_tot3sig.png|thumb|x180px|No tilt, LV 3.0V, HV 2090V]] | ||
+ | |[[Image:run_31811_tot3sig.png|thumb|x180px|Tilted at 30 degrees, LV 3.0V, HV 2090V]] | ||
+ | |[[Image:run_31810_tot3sig.png|thumb|x180px|Tilted at 45 degrees, LV 3.0V, HV 2090V]] | ||
+ | |} | ||
+ | {| border="0" cellpadding="2" | ||
+ | |+Time over threshold 5sigma | ||
+ | |[[Image:run_31809_tot5sig.png|thumb|x180px|No tilt, LV 3.0V, HV 2090V]] | ||
+ | |[[Image:run_31811_tot5sig.png|thumb|x180px|Tilted at 30 degrees, LV 3.0V, HV 2090V]] | ||
+ | |[[Image:run_31810_tot5sig.png|thumb|x180px|Tilted at 45 degrees, LV 3.0V, HV 2090V]] | ||
+ | |} | ||
+ | {| border="0" cellpadding="2" | ||
+ | |+Time over threshold 8sigma | ||
+ | |[[Image:run_31809_tot8sig.png|thumb|x180px|No tilt, LV 3.0V, HV 2090V]] | ||
+ | |[[Image:run_31811_tot8sig.png|thumb|x180px|Tilted at 30 degrees, LV 3.0V, HV 2090V]] | ||
+ | |[[Image:run_31810_tot8sig.png|thumb|x180px|Tilted at 45 degrees, LV 3.0V, HV 2090V]] | ||
+ | |} | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | or rather, signal duration | ||
Peak duration is # samples after the lower threshold crossing until the ADC value decreases by 2sigma over 2 samples, this is a measure of time over threshold in units of 8ns | Peak duration is # samples after the lower threshold crossing until the ADC value decreases by 2sigma over 2 samples, this is a measure of time over threshold in units of 8ns |
Revision as of 10:45, 11 July 2012
Cosmics, 50/50 gas, 2090V
Comparison with old (underpowered preamp) data is at CDC_signal_integration
Run numbers are 31809 (horiz) 31810 (45 deg) and 31811 (30 deg) at 3.0V, 2.09kV
dEdx attempts
time over threshold (signal duration)
Ratio of fit MPV for horizontal : 30 degr : 45 degr data are 210 : 261 : 317 or 1 : 1.24 : 1.51 Ratio of vertical path lengths should be 1 : 1.15 : 1.41 or 1 : 1.16 : 1.45 after correcting for range of angles due to scintillator height and width.
Data below are for hit threshold 5 x pedestal sigma
Try to calculate dE/dx by dividing by track length (calculated in the plane parallel to the endplates)... (A) integrate signal for 700 ns (B) position of first max in amplitude (C) integrate signal up to position of first max in amplitude
Ratio of fit MPV for horizontal : 30 degr : 45 degr data are 16.9 : 21.4 : 25.7 or 1 : 1.27 : 1.52 Ratio of vertical path lengths should be 1 : 1.16 : 1.45
Ratio of fit MPV for horizontal : 30 degr : 45 degr data are 40.7 : 54.5 : 69.2 or 1 : 1.34 : 1.70
(Purple background section has histograms from previous section with the tilted data scaled by 1/cos(tilt angle))
Track length is calculated in the plane parallel to the endplates (no z information) so I scaled it by the tilt of the prototype for the 45 degree data, the upper cosmic trigger scintillator is high up enough that the cosmics are ~ vertical.
The ratio of tilted 45deg to horizontal integration means is 1.24 (old data) and 1.28 (new data); it should be 1 (as they are already scaled by track length) so this means the tilted integrations are 25-30% too large.
The ratio of tilted 45deg to horizontal MPV of Landau fitted to amplitude/track length histogram is 0.99 (old data) and 1.07 (new data).
The ratio of tilted 45deg to horizontal MPV of Landau fitted to (integration to first maximum/tracklength) histogram is 1.07 (old data) and 1.18 (new data).
Look at time over threshold...
Search back from end of sample window until ADC value rises above a threshold, tried 3sigma, 5sigma, 8sigma (sigma= pedestal std dev). The initial hit selection is on 5sigma so all events will pass this.
or rather, signal duration
Peak duration is # samples after the lower threshold crossing until the ADC value decreases by 2sigma over 2 samples, this is a measure of time over threshold in units of 8ns