Difference between revisions of "CDC 60 40"
Line 21: | Line 21: | ||
|[[Image:run_31838_pedsig.png|thumb|x150px|Pedestal std. dev. of samples 0-99, ch20, over 1 day ]] | |[[Image:run_31838_pedsig.png|thumb|x150px|Pedestal std. dev. of samples 0-99, ch20, over 1 day ]] | ||
|[[Image:run_31838_amp20.png|thumb|x150px|Max amplitude ch20, hit threshold 4sigma ]] | |[[Image:run_31838_amp20.png|thumb|x150px|Max amplitude ch20, hit threshold 4sigma ]] | ||
− | |[[Image: | + | |[[Image:run_31838_thr5_fitamp20.png|thumb|x150px|Max amplitude ch20, hit threshold 5sigma ]] |
|} | |} | ||
Line 29: | Line 29: | ||
|[[Image:run_31840_pedsig.png|thumb|x150px|Pedestal std. dev. of samples 0-99, ch20, over 1 day ]] | |[[Image:run_31840_pedsig.png|thumb|x150px|Pedestal std. dev. of samples 0-99, ch20, over 1 day ]] | ||
|[[Image:run_31840_amp20.png|thumb|x150px|Max amplitude ch20, hit threshold 4sigma ]] | |[[Image:run_31840_amp20.png|thumb|x150px|Max amplitude ch20, hit threshold 4sigma ]] | ||
− | |[[Image: | + | |[[Image:run_31840_thr5_fitamp20.png|thumb|x150px|Max amplitude ch20, hit threshold 5sigma ]] |
|} | |} | ||
Line 37: | Line 37: | ||
|[[Image:run_31839_pedsig.png|thumb|x150px|Pedestal std. dev. of samples 0-99, ch20, over 1 day ]] | |[[Image:run_31839_pedsig.png|thumb|x150px|Pedestal std. dev. of samples 0-99, ch20, over 1 day ]] | ||
|[[Image:run_31839_amp20.png|thumb|x150px|Max amplitude ch20, hit threshold 4sigma ]] | |[[Image:run_31839_amp20.png|thumb|x150px|Max amplitude ch20, hit threshold 4sigma ]] | ||
− | |[[Image: | + | |[[Image:run_31839_thr5_fitamp20.png|thumb|x150px|Max amplitude ch20, hit threshold 5sigma ]] |
|} | |} | ||
Revision as of 14:38, 13 September 2012
60/40 Ar/CO2 and cosmics, prototype horizontal
This does not look nearly as good as 50/50 gas mix. Resolution is calculated as fitted drift distance - measured (interpolated) distance, so it is positive when the measured drift time and distance are too small. In this case they are slightly too small at small drift distance but too large at large drift distance. This could be a problem with the gas mix. For reference, plot res vs distance for tz=5,7,and 0.
Increasing tz_add to 8ns shifts the resolution up at earlier times but it hardly moves at later times. This would probably have been obvious from the tz=0 data (below) where all the measured drift distances are too large. "Measured" drift distances are actually interpolated from a table of distance calculated for a given gas mix and a range of time measurements. So for this data I should use Garfield tables for a gas mix with slower drift velocity, ie less Ar.
Suspect total flow of 60sccm might be too low for the CO2 MFC. Increase to 80sccm and repeat. Also try Garfield for different gas mixes and look at tmax.
Fitted Tmax was 573, edge is from 560 to 600ns. Garfield calcs give 560ns for 60/40, 573ns (ta-daa!) for 59/41, 588ns for 28/42 and 610ns for 57/43.
It's easiest to look at resolution far from the wire to find the best gas mix model.