Luminescence and scintillation properties of the small band gap compound LaI3:Ce3+

✍ Scribed by A. Bessiere; P. Dorenbos; C.W.E. van Eijk; K.W. Krämer; H.U. Güdel; C. de Mello Donega; A. Meijerink

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 197 KB
• Volume: 537
• Category: Article
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2004.07.224

✦ Synopsis

LaI 3 :Ce 3+ has the smallest band gap in the LaX 3 :Ce 3+ (X=F, Cl, Br, I) series and hence a potentially higher scintillation yield. The luminescence properties of LaI 3 :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 Ce 3+ emission is observed peaking at 452 and 502 nm with a yield of $16 000 photons/MeV. The drastic thermal quenching of luminescence is explained by the proximity of the Ce 3+ lowest 5d excited state to the host conduction band. Autoionization of Ce 3+ therefore prevents any scintillation effect at room temperature. The positions of Ce 3+ levels relative to the host bands were estimated.