Investigation of the irradiation history of the Iranian dates and pistachio nuts using thermoluminescence technique

Abstract

Three different varieties of Iranian fresh dates and five types of raw and salted pistachio nuts have been tested for identification of irradiation histories. Doses of 2.5, 5, 7.5 and 10 kGy from a gamma cell Gc-220 have been administrated to the samples under investigation. TL response versus dose for date and for pistachio nuts have been obtained. The effect of added ingredients such as salt in pistachio nuts, and moisture in date samples on the TL response have been studied. The fading of TL intensity of the irradiated dates and pistachio nuts have also been measured. Based on the latter results, it appears possible to identify the irradiated dates (10 kGy), within (1–2) months post-irradiation. In the salted pistachio nuts, the salt itself gives a very significant and distinguishable response. In the unsalted case, however, the difference between the irradiated and unirradiated samples seem difficult to detect due to partial overlapping of the respective responses.