New fADC with cosmics

• 50/50 mixed Ar, CO₂
• Recalibrated MFCs
• Outer plenum added to CDC prototype to prevent leaks
• New preamp
• New HVB

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.
Each event contributes one entry to the histogram, if the ADC value goes above a threshold and if the ADC passes the track-finding test. 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. The pedestal is around 100 for the new fADC, could go down to 50.
If the ADC value passes the threshold, that is a hit channel. 5 or more hits are required for track-finding. The track-finding test entails fitting the drift time histogram to find tzero (the earliest track arrival time), calculating the drift time, drift radius, finding the track which best fits any 2 hit straws and then the best track for all combinations of pairs, then fitting the drift radii for that one best track. This is described in [Yves's NIM paper] (start at page 9) The test value is true if the straw is included in the best track. For the new fADC data, 6 hits were required for the drift time to be included in the tzero fit.
NB different x axis scales, full scale is 4096 for both ADCs.

Max amplitude histo for cosmics, new fADC, unmodified HVB, mixed 50/50 at 60 sccm 2050V

Max amplitude histo for cosmics, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V

Max amplitude histo for cosmics, Struck fADCs, modified HVB, mixed 50/50 at 60 sccm, 2050V

Below: threshold set to mean + 3sigma (left); mean + 4sigma (centre); mean + 10sigma (right) for new fADC, modified HVB. Black: all hits Blue: tracked hits only (Statistics box is for tracked hits) We used mean + 10sigma for the first preamp. It looks like 4sigma is best for our current setup (sigma ~ 6)

Max amplitude histo with ped threshold=mean + 3sigma, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V

Max amplitude histo with ped threshold=mean + 4sigma, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V

Max amplitude histo with ped threshold=mean + 10sigma, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V

Below: Cosmics, 2050V, drift time - untracked, new fADC (left) and Struck fADCs (right), same straw for both.

New fADC cosmics drift time (untracked), mixed 50/50 at 60 sccm 2050V

Struck fADCs cosmics drift time (untracked), mixed 50/50 at 60 sccm, 2050V

Below: Cosmics, 2050V, drift time - untracked, new fADC, at least 6 hits, threshold 4sigma

New fADC cosmics drift time (untracked), mixed 50/50 at 60 sccm 2050V

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.

Drift radius fit residuals, new fADC, unmodified HVB, mixed 50/50 at 60 sccm 2050V

Drift radius fit residuals, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V

Drift radius fit residuals, Struck fADCs, modified HVB, mixed 50/50 at 60 sccm, 2050V

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.

Drift radius fit residuals, new fADC, unmodified HVB, mixed 50/50 at 60 sccm 2050V

Drift radius fit residuals, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V

Drift radius fit residuals, Struck fADCs, modified HVB, mixed 50/50 at 60 sccm, 2050V

Below: Fits to drift radius fit residuals

Drift radius fit residuals, new fADC, unmodified HVB, mixed 50/50 at 60 sccm 2050V

Drift radius fit residuals, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V