CaS:Bi,Zn: a promising new TL material for high LET dosimetry

The results are described of a study of TL properties of CaS samples doped with Bi and Zn prepared at the State University, Tartu, Estonia. The material shows a linear, slightly supralinear response against the alpha dose and strong supralinear behaviour against the gamma dose accompanied by a change in the glow curve shape. The material has only one emission band peaking around 470 nm. Experiments show that for doses less than 10 Gy it is 85 ± 10 times more sensitive to meV alpha particles than to 60Co gamma rays. This anomalously high value makes it very attractive for application in high LET radiation fields. Strong fading (54% in 112 h) and sensitivity to daylight hampers the application of this material in practice. (author)