Abstracts 2005

Abstract of Publication No. 502

A. Bessiere, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer, H. U. Güdel, C. de Mello Donega and A. Meijerink
Luminescence and scintillation properties of the small band gap compound LaI3:Ce3+
Nucl. Instr. Methods Phys. Res. A 537, 22-26 (2005)      Full Text (PDF)      DOI-Link     

Abstract: LaI3:Ce3+ has the smallest band gap in the LaX3:Ce3+ (X=F, Cl, Br, I) series and hence a potentially higher scintillation yield. The luminescence properties of LaI3:Ce were investigated by means of optical, X-ray, and g-ray excitation. Unexpectedly, the compound is a poor scintillator at room temperature but presents good scintillation properties for temperatures below 100 K where Ce3+ emission is observed peaking at 452 and 502 nm with a yield of 16000 photons/MeV. The drastic thermal quenching of luminescence is explained by the proximity of the Ce3+ lowest 5d excited state to the host conduction band. Autoionization of Ce3+ therefore prevents any scintillation effect at room temperature. The positions of Ce3+ levels relative to the host bands were estimated.

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