The temporal stability of the CsI detector gains can be studied by plotting the software gains against the data run number, for each illuminated CsI crystal. Figure 4.8 shows this plot for the CsI detectors during 100 runs, or a time period of 4 days. One can see that the gains show a large shift beginning at run 492, at which time the CsI array was warmed from 14C to 25. The software gains increase to compensate for the fact that the CsI crystals output less light at warmer temperatures.
Figure 4.8: Gain plotted against Run Number for the CsI detectors.