The Lu-doping effect on the emission and the coloration of pure and Ce-doped BaF2 crystals

The absorption and luminescence properties of as-grown and X-ray irradiated pure, Lu- and Ce-doped and Lu/Ce co-doped BaF2 crystals were studied. The intensity of the fast cross-valence emission in Lu-doped crystal is similar to that for pure BaF2, whereas the slow component is three times lower. A weak coloration in the visible range appears under high dose irradiation of BaF2:Lu. The introduction of lutetium into BaF2:Ce crystal leads to the main emission bands (305/325nm) quenching and appearance of luminescence at 355nm. The defects responsible for the additional emission and coloration of BaF2:Ce, Lu can probably be connected with charge compensative fluorine interstitials.