Afterglow Suppression and Non-Radiative Charge-Transfer in CsI:Tl,Sm

Suppression of afterglow in co-doped CsI:Tl is found to be an order of magnitude more effective in CsI:Tl, Sm than in CsI:Tl, Eu. Rate equations predict that deep electron traps introduced by co-doping with samarium effectively scavenge electrons from shallow traps associated with thallium, thus suppressing afterglow in the time domain of tens of milliseconds. In addition, combined radioluminescence and thermoluminescence experiments suggest that electrons released by samarium recombine non-radiatively with trapped holes, thus providing a mechanism for suppression of hysteresis.
Ab

initio
quantum chemistry calculations support the conclusion that non-radiative charge-transfer transitions in CsI:Tl, Sm are enabled by the presence of low-energy excited states of within the ground configuration.