Spectral changes in the thermoluminescence of erbium in strontium fluoride

Thermoluminescence from alkaline-earth halides with rare-earth ions shows e mission signals from both the host and the dopants. In many cases each glow peak contains a complete set of emission lines from the rare-earth dopant, but in the case of Er in SrF2 the spectra change significantly with temper ature. In part this is interpreted as evidence for a range of erbium sites, and in part as evidence for energy transfer between erbium states. Near 20 0 degreesC the conversion between the 545 and 525 nm emission lines follows a thermally activated pattern consistent with the differences in their ini tial energy states; This pair of transitions define more glow peaks than si gnals from the other Er lines. Spectrally analysed recording of the thermol uminescence is thus essential to separate the closely spaced glow peaks.