Scintillation properties of K 2 LaCl 5 :Ce microcrystals embedded in KCl host

Scintillation properties under γ‐ray excitation and luminescence properties under X‐ray excitation of KCl with embedded K 2 LaCl 5 :Ce microphase crystals have been investigated. KCl–LaCl 3 (2 mol%)–CeCl 3 (0.1 mol% and 0.02 mol%) show scintillation yields of 15000–18000 photons/MeV with two decay time components of 300–420 ns and 1.2–1.9 µs. These properties compare with those of K 2 LaCl 5 :Ce bulk crystal. The luminescence study and scanning electron microscopy data indicate that the KCl–LaCl 3 –CeCl 3 system contains K 2 LaCl 5 :Ce microcrystals of 10–50 μm size. The decrease of the intensity contribution and decay times of the slow component in the scintillation pulse of microcrystals compared with those in K 2 LaCl 5 :Ce single crystals are discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)