A comprehensive comparative study of the predose effect for three quartz crystals of different origin.

The study of the thermoluminiscence (TL) sensitivity of quartz due to heat and irradiation treatments is of importance in dating and retrospective dosimetry. A comprehensive comparative study of the predose effect was carried out for three types of quartz of different origin. Complete TL vs. dose and sensitivity S vs. predose curves were obtained for the dose range of 0.1 < D < 400 Gy. Additional complete sensitivity vs. predose curves were obtained for samples which underwent a combined predose irradiation and a subsequent heat treatment to 500 degrees C. Although the TL vs. dose curves showed very different behaviours, the sensitivity vs. predose curves showed several common characteristics. The sensitivity vs. predose curves showed abrupt changes approximately 10 Gy. The sensitivity after a combined predose irradiation and heat treatment to 500 degrees C showed a very gradual change in the whole dose range studied. These results are explained qualitatively by using the modified Zimmerman model for quartz.