Time-resolved spectroscopy of CsI(CO3) scintillator

The spectral-kinetics characteristics of short-living absorption and luminescence induced by an electron pulse irradiation (Ee=0.25 MeV, t1/2= 7ns, W=2×1010÷4×1012 electron/cm2) in CsI(CO3) crystal are studied. It is shown that the scintillation pulse of CsI(CO3) crystal is caused by the radiative annihilation of perturbed two-halogen excitons of two types, which are located in nearby impurity-vacancy dipole [CO32-−υa+] anion sites. The processes responsible for post-radiation rise and decay of both CO32--related luminescence bands with maxima at 2.8 and 3.2 eV are monomolecular with the thermal activation energy Erise=0.1 eV and Edecay=0.05 eV. The cathodoluminescence pulse kinetics is discussed in the terms of the thermally assistant release of holes captured by CO32--ions and the formation of CO32--perturbed two-halide excitons.