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 14
C 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.