FLUORESCENCE PROCESSES AND SCINTILLATION OF CEF3 CRYSTALS EXCITED BY UV AND X-RAY SYNCHROTRON-RADIATION

Photoluminescence properties of CeF3 have been investigated. Two kinds of emitting centers have been identified: regular Ce3+ sites exhibiti ng two close emission bands (285 and 300 nm) and a fast fluorescence ( 20 ns) and several physically different perturbed Ce3+ sites giving ri se to a broad emission band near 340 nm and a longer fluorescence (30- 40 ns) the decay time of which varies with wavelength. An energy trans fer occurs between these two kinds of centers. Scintillation propertie s have been studied under UV and X-ray excitation. The additional fast decay always observed at short time under ionizing radiation is inter preted by a temperature dependent luminescence quenching phenomenon du e to high excitation density.