6.3. Inorganic Scintillators 355
Figure 6.3.4: Decrease in gain of a detector based on undopedCsI(19).Figure 6.3.5: Effect of proton irradiation on light transmission in
PhWO 4 (26).The biggest problem withNaI:Tlis its vulnerability to moisture. Because of
this hygroscopicity it must be used in a sealed assembly. This, however, is not a
bottleneck for using it in real systems since the size of the detector is usually small
and the light can be guided through optical fibers.