# Presentation: 522626

## Study of the QIE Calibration & Response (Current Injection Mode) at CalDet

- N.Saoulidou 28-10-03

## 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.

## Rms vs Mean for all channels

- 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.

**(rms/mean)  vs mean**

**               ****rms  vs mean**

## “Pathological” channels

- 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**

**Strip vs Plane**

**(rms/mean)  vs mean for Run 80302**

**Strip vs Plane**

**Strip vs Plane**

## 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  % 

- 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  % **

- Removing “Pathological” channels

## Linearity 

- 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 these channels (not just a broader distribution with the same mean).

**  ****:15.83 **
**  ****: 1.68**

**  ****:15.12 **
**  ****: 1.51**

**  ****:15.09 **
**  ****: 1.37**

**Mean vs dac value**

**Residuals no cuts**

**Residuals     (Range 7 excluded)**

**Residuals     (Range 7  &  “bad” channels excluded)**

**Residuals for “bad” channels     (Range 7 excluded)**

## Summary

- After processing all Near Current Injection runs at CalDet 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.