CDC prototype more on timing

Current analysis code procedure:

1. Calculate s.d. of pedestal for first 100 samples, 100 events, save for later use (sigma)

For each event...

1. Calculate mean pedestal over 100 samples ending 10 samples before the trigger time (every 4th of these samples also works)
2. Search forward for sample x where adc value > high threshold n₁ sigma
3. Step back p samples to sample x-p, take adc value of sample x-p to be local pedestal value
4. Subtract local pedestal value from a number (10+p) of samples starting at sample x-(p+5) to the LE algo for desampling
5. Search through desampled data, start with last sample (highest adc value) search backwards until adc value < low threshold n₂ sigma
6. Calculate time where interpolated unsampled data cross n₂ sigma, and add to time of sample x-p, this is the estimated drift time.

Below are plots of desampled adc values (z) using different values for p (local pedestal lead time ahead of first/high threshold crossing) for high threshold of 5 sigma. x-axis=0 corresponds to sample x-p-4.2, x-xaxis=5 corresponds to 1+x-p-4.2, etc. 5 desampled values per 8ns sample, all events for ch17 (central straw) included (no tracking)

p=4

p=5

p=2

p=3

High threshold 4 sigma

4 sigma, p=2

4 sigma, p=3

High threshold 6 sigma

6 sigma, p=2

6 sigma, p=3

Looks like p=3 should work best.

Previous best resolutions for 50/50 gas mix using single threshold of 4sigma:
Resolutions for ch20 ignoring hits before tzero, using 50/50 mix in Garfield and wire diameter of 17.8um instead of 20um, 2100V (left) and 2050V (right).

50/50 Ar/CO2 gas mix Resolution vs fitted drift distance, hit thr=4sigma dt=7ns hits before tzero ignored

50/50 Ar/CO2 gas mix Resolution vs fitted drift distance, hit thr=4sigma dt=10ns hits before tzero ignored

Current best resolutions for 50/50 gas mix and 17.8um wire, 2100V, using high threshold 5sigma followed by low threshold 1sigma, p=3
Ignoring hits before tzero (tzero = fitted value + dt, dt=6ns)

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits ignored

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits ignored

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits ignored

Resolution of ch20 (central straw, 17) with early hits moved to t0 + 1ns (left) and t0 + 2ns (right), only showing events with early hit in ch20

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits moved to t0+1ns, early hits in ch20 only

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits moved to t0+2ns, early hits in ch20 only

Moving early hits to tzero+1ns

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits moved to t0+1ns

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits moved to t0+1ns

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits moved to t0+1ns

Below: 2100V with high threshold 5sigma, low threshold 1sigma (left) high threshold 5sigma, low threshold 2sigma (center) and 2050V with high threshold 5sigma, low threshold 1sigma (right)

Ch 20 (straw 17) resolution 2100V thr 5 and 1, tz 6ns, early hits moved to t0+1ns

Ch 20 (straw 17) resolution 2100V thr 5 and 2, tz 6ns, early hits moved to t0+1ns

Ch 20 (straw 17) resolution 2050V thr 5 and 1, tz 8ns, early hits moved to t0+1ns

Resolution ch20 (straw 17) 50/50 Ar/CO2 2100V thr5, tz 6ns early hits moved to t0+1ns... With and without de-sampling, for trackfinding including hits within 0.4mm and 0.1mm of possible track

Ch 20 (straw 17) resolution 2100V thr 5, 6ns, early hits moved to t0+1ns, code track63, with and without de-sampling and for trackfinding ranges of 0.4mm and 0.1mm