On effect of some impurities on LaOBr-Tb luminophor properties

The effect of some element impurities on the LaOBr-Tb luminophor optical properties is investigated, the luminophor being used for manufacturing intensifying X-ray screens. It is established that, among lanthanides, Ce3+ (luminogen and sensitizer), Sm3+ (quencher of stationary luminescence), Eu3+ and Yb3+ (quenchers of phosphorescense) exert most considerable effect on the LaOBr-Tb luminescence. Such an effect of these ions is explained by the structure of the 4f-shell. The X-ray luminescence amplification of LaOBr-Tb-luminophor is detected following introduction Nb, Dy, Tm, Yb, Fe and Ni into it in concentration approximately 10-5 g-atom x mol-1. The effect is explained by suppression of the luminescence quenching conforming to the Auger mechanism. Taces of radioactive impurities accompanying lanthanum are shown to cause weak background radio luminescence due to α-radiation. A high-sensitive photographic-luminescence method for detecting these impurities in the source material (lanthanum oxides) is developed. The significance of the decscribed phenomena for medical and indastrial roentgenography is considered