THE SCINTILLATION PROPERTIES OF CERIUM-DOPED LANTHANUM FLUORIDE

We report on the scintillation properties of cerium-doped lanthanum fluoride (LaF3), a newly discovered dense (5.9 g/cm3) heavy-atom scintillator. We have investigated four dopant concentrations (0.01%, 1%, 10% and 50% mole fraction of CeF3) and measured the emission spectrum, light output and decay time distribution. The light output increases with increasing cerium concentration until a maximum is reached at 2200 photons/MeV at 10% CeF3, then decreases to 1900 photons/MeV at 50% CeF3. The emission spectrum depends on concentration, but tends to consist of a pair of peaks centered at approximately 350 and 290 nm, with the lower cerium concentrations having a greater fraction of shorter-wavelength emissions. While the decay time distribution also depends on concentrations, all samples are well described by the sum of three exponential components (3.0 ns, 26.5 ns, and a long component that varies between 140 and 275 ns), with the fraction of the 3.0 ns fast component increasing from 10% at 50% cerium to 15% at 1% cerium, and the fraction of the long component increasing from 3% at 50% cerium to 21% at 1% cerium. These scintillating compounds may be useful for applications where high rates and good stopping power are required, such as medical imaging and nuclear instrumentation.