OPTICAL SPECTROSCOPY OF CE3+, TB3+ AND EU3+ IN NEW SCINTILLATING GLASSES

Optical absorption, luminescence and excitation spectra of new silicat e scintillating glasses doped with Eu3+, Ce3+ and Tb3+ have been measu red at room temperature. The spectra have been assigned and the lifeti mes of the emitting states measured. In the case of the Ce3+ doped gla ss a low Stokes shift, probably responsible for the relatively high em ission quantum yield induced by the predominantly radiative decay, has been evidenced. In the case of the Eu3+ doped glasses, information ab out the distortion of the local geometry around the impurity has been obtained through the intensity ratio I(D-5(0)-->F-7(2))/I(D-5(0)-->F-7 (1)). The Tb3+ doped glass shows a very efficient emission in the gree n spectral region characterised by a long lifetime around 2.7 ms with no evidence of concentration quenching.