Thermally and optically stimulated processes in X-irradiated scheelite type crystals

Abstract

Abstract. -In tungstate and molybdate crystals having scheelite structure various (intrinsic and extrinsic) hole and electron centres are created by X-irradiation at liquid nitrogen temperature. Several of these centres have been thoroughly investigated by electron paramagnetic resonance (EPR) measurements. Their thermal decay and optical bleaching, resp., can be related to glow peaks of thermoluminescence and thermally resp. optically stimulated conductivity as well as characteristic changes in optical absorption. For the case of CaW0 4 doped with lead some of these centres and typical transport processes are discussed. From analysis of EPR data, polarization and spectral composition of thermoluminescence, optical absorption, spectral response of optically stimulated conductivity and re-excited thermoluminescence detailed information about electronic structure can be obtained.

Influence of Gd3+ Concentration on PbWO4:Gd3+ Scintillation Characteristics

“…However, the Pb 3+ centre was not detected by EPR in PWO [24,25], contrary to what was observed e.g. in isostructural CaWO 4 : Pb [26]. Suppression of the red emission due to Gd 3+ doping is in agreement with the proposed compensation effect of these trivalent dopants on hole centres [3].…”