LUMINESCENCE OF CE-3+ AND EU-2+ ACTIVATED BAMGF4 UNDER X-RAY-EXCITATION

The luminescence of Ce**3** plus and Eu**2** plus -doped BaMgF//4 over a wide range of compositions under X-ray excitation is described. It is found that under X-ray excitation, however, the emission characteristics are completely different (curve X). The Eu**2** plus emission now shows up as the stronger band centered at 2. 95 ev. This can be explained as follows. X-ray radiation will result in the formation of electrons and holes. The results then suggest that the excitation of the emitting center is mainly due to the trapping of holes. The large amount of Eu**2** plus emission upon X-ray excitations as compared to that of Ce**3** plus emission is ascribed to efficient hole trapping by the Eu**2 plus ions.