EJ-444 塑料闪烁体

EJ-444 consists of a thin piece of EJ-212 plastic scintillator with a layer of silver activated zinc sulfide phosphor (ZnS:Ag) applied to one side. The primary use of EJ-444 is the detection of alpha and beta particles in health physics instrumentation. A non-coated plastic scintillator may also be used for this purpose, but the amplitudes of the alpha and beta pulses are sufficiently similar to make it difficult to separate the two by simple counting electronics making use of counting windows. In contrast, the ZnS:Ag layer on the EJ-444 is made just thick enough to stop all common alpha particles while allowing many low energy betas to pass into the plastic scintillator layer for detection. C-14 betas may be detected with moderate efficiency.