SCINTILLATION PROPERTIES OF K2LACL5 WITH CE DOPING

In this work we present the scintillation properties of K-2 LaCl5 doped with Ce3+ concentrations of 0, 0.1, 1 and 10%. Under X-ray excitation the crystals show efficient Ce3+ (5d-4f) luminescence between 340 and 400nm. Depending on the Ce concentration, the light yields vary between 24,000 and 50,000 photons/MeV (ph/MeV). Experiments with 662keV gamma ray excitation show light yields varying between 13,000 and 30,000 ph/MeV. For Ce luminescence a single exponential decay time of approximately 40 ns is expected. However, for K2LaCl5:10%Ce, the decay is not single exponential. As a function of the time t, it can be described by a 1/t(1.63) behaviour for large t. With a crystal of K2LaCl5:10%Ce we obtained an energy resolution of 5.1% for 662 keV gamma ray excitation of Cs-137.