Study of the QIE Calibration Response Current Injection
Study of the QIE Calibration & Response (Current Injection Mode) at Cal. Det N. Saoulidou 28 -10 -03 1
Procedure • Processed all Near Cal Check Runs from 26 -9 -03 to 20 – 10 -03. • Examined the behavior of the mean & the rms of all the Near Electronics Channels. • Identified “pathological” cases. 2
Rms vs Mean for all channels (rms/mean) vs mean • • • rms vs mean The distributions of the rms or the (rms/mean) vs mean, appears to have for all 8 ranges some relatively large values. The frequency of channels with (rms/mean) > 1. % is : Dac value > 0. 13 % Dac value > 3000. 0. 18 % Dac value > 36000. (Range 7) 0. 50 % For small dac values the (rms/mean) may not be a good estimator of the performance of each channel and that is why the percentage of “problematic” channels drops significantly if we consider only events with dac values >3000. 3
“Pathological” channels • Strip vs Plane (rms/mean) vs mean for Run 80302 Plotting the strip vs plane for the channels that had large rms values we found three that mostly show that kind of behavior : crate module minder ch. master ch. 1 6 8 2 2 2 10 5 2 1 13 1 4
Removing “Pathological” channels • After removing the problematic channels the only cases with large rms values that remain are mostly in range 7 and the range transitions. • The frequency of channels with (rms/mean) > 1. % is now : Dac value > 0. 11 % Dac value > 3000. 0. 06 % Dac value > 36000. (Range 7) 0. 33 % 5
Linearity Mean vs dac value Residuals no cuts Residuals : 15. 83 : 15. 12 : 1. 68 : 1. 51 Residuals (Range 7 & “bad” channels excluded) (Range 7 excluded) Residuals for “bad” channels (Range 7 excluded) : 15. 09 : 1. 37 • • The distribution of the residuals (for all channels) is a gaussian with a sigma of ~ 15 counts if we exclude range 7 and the “bad” channels (that do not affect the overall distribution much due to their small number). The distribution of the residuals for the “bad” channels has a larger rms and long tails (excluding again range 7) which indicates that the mean value is also shifted for 6 these channels (not just a broader distribution with the same mean).
Summary • After processing all Near Current Injection runs at Cal. Det from 26 -9 -03 to 20 -10 -03 we identified 3 (out of 1440) “pathological” channels (large rms & relatively large residuals). • After excluding these channels the percentage of large rms events (for dac values > 3000. ) is ~ 0. 06%, with 60 % of them occurring at range 7. 7
- Slides: 7