Figure 1.

Simple representation of electron and hole ion pair production by ionizing radiation, movement (using arrows similar to those followed in books[14]), trapping, re-trapping, transfer between the traps, recombination, and luminescence emission. (A) Shows a simple case of TL or OSL with no intertransfer of the charge carrier among the traps. (B) Shows the delayed emission (DOSL) through photo-transfer via shallow traps (used in optically enhanced phosphorescence) and also if the luminescence center has higher lifetime (used in POSL, which is the other type of DOSL). (C) Shows the modes of photo-transferred optically stimulated luminescence (PTOS), photo-transferred thermoluminescence (PTTL), and cooled optically stimulated luminescence (COSL). 1- electron trap, 2- hole trap or recombination center associated with a luminescent center, 3- shallow trap, and 4- deep trap responsible for photo-transfer. For details, see text