Trap-level spectroscopy of actinide-doped phosphors. II. SrSO₄:²⁴¹Am

Abstract

For pt.I see ibid., vol.17, p.5851 (1984). Trap-level spectroscopic studies of SrSO4 phosphor doped with 241Am were conducted using ESR and thermally stimulated luminescence (TSL) techniques. The formation of electron and hole traps due to internal alpha -irradiation (from the decay of 241Am) and external gamma -irradiation were distinguished by carrying out the studies on pure SrSO4 and also on SrSO4 doped with europium (lanthanide analogue of Am). The ESR studies on these samples have shown that the paramagnetic radicals SO4-, SO3-, O3-, S5+, SH2- were stabilised in SrSO4 under different dopant and irradiation conditions. The radical SH2- is detected for the first time. From the ESR studies of thermal stabilities of radical ions produced and their correlation with TSL peaks, the role of paramagnetic molecular species in the electron and hole trapping and thermally stimulated free radical reactions were identified and the corresponding activation energies and frequency factors were determined.