Kinetics of luminescence of CsI single crystals scavenged by Y3+

Abstract

AbstractCsI single crystals were grown from the melt scavenged by Y3+ (YCl3) addition in 6.7·10−4–6.7·10−3 mol·kg−1 range. The addition of the scavenger amounts comparable with the total concentration of the oxygen‐containing admixtures in molten CsI results in complete destruction of the latter. Because of this, the intensity of the band with a maximum at 2.8 eV in radioluminescence spectra caused by the oxygen‐containing admixtures (anion vacancies) considerably decreases, and the fraction of the slow 2μs‐component corresponding to these admixtures becomes lower than 0.01 (0.007). The addition of larger quantities of YCl3 leads to the appearance of a wide band with a maximum at 2.8 eV caused by cation vacancies, and the intensity of the slow 2μs‐component increases to 0.02. The maximum ratio of two faster components with the decay constants equal to 7 and 30 ns reaches 0.65:0.33 at Y3+ concentration in CsI melt equal to 6.7·10‐3 mol·kg‐1, the effective luminescence time of fastest components is ca 14 ns. The dependence of the ‘Fast/Total ratio’ on Y3+ concentration passes through its maximum (0.81) corresponding to the equivalence of Y3+ and O2− concentrations in the growth CsI melt.