Auger-free luminescence characteristics of Rb₁ ¹ _xCs_xCaCl₃

Fast scintillation materials based on ternary halide mixed crystals, Rb₁ ¹ _xCs_xCaCl₃ were synthesized. Broad luminescence bands were observed around 360 nm and can be ascribed to Auger-free Luminescence (AFL) for vacuum ultraviolet core-level excitation. Several luminescence bands for interband excitation were also observed. For X-ray excitation, the band that is ascribed to AFL could be clearly detected. The scintillation decay components due to the AFL had decay time constant of 0.8 ns for RbCaCl₃ and 2.0 ns for Rb₁ ¹ _xCs_xCaCl₃ (x º0). CsCaCl₃ had the largest light yield of the AFL component, exceeding 1200 photons/MeV, which was slightly lower than that of BaF₂. The light yield of the AFL component increased linearly with Cs content.