Comparative Study of a CsI and a ZnSe(Te/O) Scintillation Detector's Properties for a Gamma-ray Measurement

Abstract

A ZnSe crystal based on a II-VI compound semiconductor has various physical properties: electroluminescent, photoelectric, luminescent and scintillation. Activated ZnSe crystals are highly-efficient scintillators, and they are already being applied to the detecting units of a X-ray introscopy and a dosimetric system. ZnSe-based scintillators have a high absolute light output, and their radiation spectra matches well with the Si-photodiode spectral sensitivity. The present study was performed by using a polished ZnSe and CsI(TI). ZnSe is a low-density crystal(5.42 g/cm(3)). The emission wavelength of ZnSe(Te) is 610 nm and ZnSe(O) is 592 nm. We have fabricated 10x10x1 mm and 10x10x2 mm ZnSe crystals in which the activators were doped with tellurium and oxygen. ZnSe and CsI crystals were mounted on a S3590-08 HAMAMATSU PIN photodiode and an R3479 HAMAMATSU PMT. Teflon tape as a reflector for the PIN photodiode and PMT. Gamma-ray spectrum measurements were performed by using Am-241, Co-57, Ba-133 and Cs-137 radio isotopes. We have compared the measured spectra of ZnSe and CsI under the same conditions.