K2CeCl5: A new scintillator material

We report the scintillation properties of a new material, K2CeCl5, which was grown by vertical Bridgman technique. Under excitation of 4.5 MeV α-particles, the Ce3+ emission had a single peak centered at 370 nm with a width of 20 nm. The scintillation light output was estimated to be ∼30,000 photons/MeV for γ excitation at 662 keV and ∼24,000 photons/MeV γ equivalent (assuming an α/γ ratio of 0.34) under α excitation. The smaller light yield for α s can be partly explained by surface damage of the sample during polishing and subsequent partial oxidation of the Ce luminescence centers. The energy resolution at 662 keV was measured to be about 5.8%. Importantly, K2CeCl5 is found to be much less hygroscopic than lanthanum halide scintillators and may therefore preferred in applications where enclosing the material is not feasible.