Absorption, excitation and photoluminescence spectra
The optical transmission spectra of glasses are shown in Fig. 1.
Increase in the concentration of cerium ions leads to a slight red-
associated with f–f transitions in the terbium ion [7]. The trans-
mission coefficient at 350 nm is ?70%. The absorption peak at
485 nm is recorded in all samples (Fig. 1). After irradiation with
electron pulse train (100 pulses) it was observed a decrease of the
samples transmittance with a shift of the transmission edge. The
absorption peaks in the range 350–378 nm could not be distin-
guished in the spectra of the irradiated samples. (Fig. 1, b). It was
also found that the samples with the lowest concentration of
cerium are most sensitive to changes in the optical properties
under electron irradiation.