Abstract: The instant invention teaches a method of preparing a luminescent detecting material for use in UV dosimetry which utilizes phototransferred luminescence. The detecting material has a set of shallow dosimetry traps for trapping electronic charge carriers, which are thermally released upon heating to a first temperature, and a set of deep traps for trapping electronic charge carriers, which charge carriers are released upon heating to a second temperature. The detecting material is prepared by irradiating the detecting material to fill the shallow and deep traps with charge carriers, heating the material to release charge carriers from the shallow traps, and then cooling the material. When the detecting material is subsequently exposed to ultraviolet light a proportion of charge carriers will be released from the deep traps to be retrapped in the shallow traps, thereby allowing for the measurement of phototransferred luminescence by thermal or optical stimulation.