EJ-444 塑料闪烁体

ej-444 consistsof a thin piece of ej-212plastic scintillator with alayer of silver activated zinc sulfide phosphor (zns:ag) applied toone side. the primary use of ej-444 is the detection of alpha andbeta particles in health physics instrumentation. a non-coatedplastic scintillator may also be used for this purpose, but theamplitudes of the alpha and beta pulses are sufficiently similar tomake it difficult to separate the two by simple countingelectronics making use of counting windows. in contrast, the zns:aglayer on the ej-444 is made just thick enough to stop all commonalpha particles while allowing many low energy betas to pass intothe plastic scintillator layer for detection. c-14 betas may bedetected with moderate efficiency.