Novel γ- and X-ray scintillator research: on the emission wavelength, light yield and time response of Ce3+ doped halide scintillators

This work reviews the scintillation properties of many Ce3+ doped halide compounds studied during the past two decades with the aim to find new relationships between scintillation performance and materials properties. Three major types of compounds are reviewed; lanthanide trihalides LnX(3), (pseudo)-elpasolites M(2)ALnX(6) and ternary halides A(m)Ln(n)X(o) where M and A are alkali cations, Ln is a rare earth cation and X is a halide anion. We will address the relationship of the emission wavelength of Ce3+ and its Stokes shift with the structure, type of anions, coordination number, band gap etc. A comparison between the observed absolute scintillation yield with the fundamental limits will be made. Scintillation losses due to thermal ionization processes and the relationship between Stokes shift, self absorption, and decay time lengthening are treated. Various trends will be identified that may guide us in the continuing quest for better scintillators. (C) 2009 WILEY-VCH Veriag GmbH & Co. KGaA, Weinheim