Application of optical techniques to phoswich detectors composed of ZnS(Ag) for simultaneous counting of radiations emitted from actinides

Usuda, Shigekazu; Yasuda, Kenichiro   ; Sakurai, Satoshi 

The authors have developed phoswich detectors with ZnS(Ag) as an essential component. The phoswich detectors consist of plural scintillators, which have specific sensitivity for each radiation and different decay time from each scintillator, and enable us to count simultaneously alpha, beta() rays, thermal and/or fast neutrons emitted, when pulse shape and/or pulse height discrimination techniques are skillfully applied. In addition, if optical filters are suitably applied to the phoswich detectors, discrimination properties are improved. In this presentation, the authors introduce (1) summary of the rise time properties of scintillators and effects of optical techniques such as optical filters obtained under the almost same conditions, and (2) examples of application of optical techniques to improve the discrimination characteristics of the phoswich detectors.