Applicability of NaCl as a -Ray Dosimeter in Radiological Accidents

In radiation accidents, especially those occuring in residential regions, where the general public may receive a significant dose, it will be very advantageous to define a material that could be easily found in accident location to be used as a radiation dosimeter. One of such materials is the household NaCl that always exist everywhere and could be easily collected. For that reason, the Thermoluminescence (TL) response of one of the most known NaCl brands in Egyptian market has been studied. Results showed that TL response varies considerably if the salt is directly measured. Such variations were attributed to the different particle size in the salt package. Different particle sizes have been achieved using different 10 sieving nets ranging from 45 m up to 750 m. 7-9 chips of (20 ± 0.5 mg) have been prepared for each particle size and then irradiated with constant gamma dose. The chips were measured at a heating rate of 5 C /sec from 50 C to 350 C using Harshaw Model 3500 TLD Reader. It has been found that all particle sizes have the same TL glow curve with varying TL intensity that is proportional to the particle size and approach saturation as the particle size increases. The largest size has been chosen to study the dose response and fading effect. Dose response investigations showed that the TL phenomenon in NaCl could be interpreted in terms of 1 order kinetic models. On the other hand, the integral TL intensity has a linear response in the range from 250 mGy to 20 Gy. Fading effect has been investigated along 24 days and the results showed that the TL integral intensity reaches stability after 15 days approximately. The current study showed that the household NaCl could be used as an efficient retrospective dosimeter in cases of radiological accidents. Other common brands of household NaCl should be studied in the same manner presented in this study to build a reference data base to be used for comparison in case of radiation accidents in Egypt.