Difference between revisions of "New fADC with cosmics"
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− | Below: Cosmics, 2050V, max amplitude histograms, new fADC with unmodified HVB (left), with modified HVB (attenuation x0.5 before the preamp input) (center) and Struck fADCs with modified HVB (right), same straw for each. The pedestal has been subtracted (this is around 100 for the new fADC, could go down to 50.) | + | Below: Cosmics, 2050V, max amplitude histograms, new fADC with unmodified HVB (left), with modified HVB (attenuation x0.5 before the preamp input) (center) and Struck fADCs with modified HVB (right), same straw for each. The pedestal has been subtracted (this is around 100 for the new fADC, could go down to 50.) Each event contributes one entry to the histogram, if the ADC value goes above a threshold. The threshold is the pedestal mean (calculated for 100 events, the first 100 time samples in each event are included) + 5 x its standard deviation. The max amplitude is the first maximum in the ADC value after crossing the threshold, minus the pedestal mean. |
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NB different x axis scales, full scale is 4096 for both ADCs. | NB different x axis scales, full scale is 4096 for both ADCs. | ||
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[[Image:run_31598_amp7.png|thumb|420px|Max amplitude histo for cosmics, Struck fADCs, modified HVB, mixed 50/50 at 60 sccm, 2050V]] | [[Image:run_31598_amp7.png|thumb|420px|Max amplitude histo for cosmics, Struck fADCs, modified HVB, mixed 50/50 at 60 sccm, 2050V]] | ||
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+ | Below: the threshold was reduced to mean + 3 sigma | ||
+ | {| border="0" cellpadding="2" | ||
+ | |width="420pt"| | ||
+ | |width="420pt"| | ||
+ | [[Image:run_31599_amp6_thr3.png|thumb|420px|Max amplitude histo with ped threshold=mean + 3sigma, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V]] | ||
+ | |width="420pt"| | ||
+ | |} | ||
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Revision as of 15:46, 12 April 2011
- 50/50 mixed Ar, CO2
- Recalibrated MFCs
- Outer plenum added to CDC prototype to prevent leaks
- New preamp
- New HVB
Software methods are mostly as described in [Yves's NIM paper] (start at page 9)
Below: Cosmics, 2050V, max amplitude histograms, new fADC with unmodified HVB (left), with modified HVB (attenuation x0.5 before the preamp input) (center) and Struck fADCs with modified HVB (right), same straw for each. The pedestal has been subtracted (this is around 100 for the new fADC, could go down to 50.) Each event contributes one entry to the histogram, if the ADC value goes above a threshold. The threshold is the pedestal mean (calculated for 100 events, the first 100 time samples in each event are included) + 5 x its standard deviation. The max amplitude is the first maximum in the ADC value after crossing the threshold, minus the pedestal mean.
NB different x axis scales, full scale is 4096 for both ADCs.
Below: the threshold was reduced to mean + 3 sigma
Below: Cosmics, 2050V, drift time - untracked, new fADC (left) and Struck fADCs (right), same straw for both.
Below: Cosmics, 2050V, drift radius fit residuals (radius of fitted track - radius interpolated from Garfield drift time calcs)
New fADC with unmodified HVB (left), with modified HVB (center) and Struck fADCs with modified HVB (right), same straw for each.
Below: Cosmics, 2050V, drift radius fit residuals with chosen straw omitted from fit
New fADC with unmodified HVB (left), with modified HVB (center) and Struck fADCs with modified HVB (right), same straw for each.
Below: Fits to drift radius fit residuals