Cerium fluoride, a new fast, heavy scintillator

The authors describe the scintillation properties of cerium fluoride CeF₃, a recently discovered, heavy (6.16 g/cm³ ), inorganic scintillator. Its fluorescence decay lifetime, measured with the delayed coincidence method, is described by a single exponential with a time constant of 20±1 ns. The emission spectrum peaks at a wavelength of 340 nm, and drops to less than 10% of its peak value at 315 nm and 460 nm. When a 1-cm optical-quality cube of CeF₃ is excited with 511-keV photons, a photopeak with a 20% full width at half maximum is observed at approximately half the light output of a bismuth germanate (BGO) crystal with similar geometry. Also presented are measurements of the decay time and light output of CeF₃ doped with three rare-earth elements (Dy, Er, and Pr). The short fluorescence lifetime, high density, and reasonable light output of this scintillator suggest that it would be useful for applications where high counting rates, good stopping power, and nanosecond timing are important, such as medical imaging and nuclear science