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(Tl). ZnSe is a low-density crystal(5.42 g/cm3). The emission wavelength of ZnSe(Te) is 610 nm and ZnSe(O) is 592 nm. We have fabricated 10×10×1 mm and 10×10×2 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 241Am, 57Co, 133Ba and 137Cs radio isotopes. We have compared the measured spectra of ZnSe and CsI under the same conditions.