A study of fundamental characteristic about the fluorescent glass dosimeter

Abstract

The radiophotoluminescence glass dosimeter has realized high measurement accuracy owing to its various advantages. Several fundamental examinations were performed in order to use this system for radiation control measurement. When annealing was repeated, pre-dose increased gradually. Therefore, the elements needed to be washed after about every ten times of annealing. When measurement was made without performing annealing, the coefficient of variation increased as a function of the irradiation count. When stored at room temperature, measured value increased sharply for 3 hours after the start of irradiation. Then, it increased moderately until after approximately 24 hours from the start. On the other hand, when preheating was performed (for 30 minutes, 70 ℃), measured value was about 31 mGy, which is equivalent to an exposure dose, irrespective of elapsed time. An exposure dose and measured value showed a good correlation. The coefficient of variation decreased as the exposure dose increased, and in the range of 1 mGy or more, it decreased to 3% or less. As for direction dependency, the sensitivity was highest at the front of the element (0 degree), and decreased gradually toward 45 degrees right and left. Use of the glass dosimeter in high magnetic field did not affect the measured values.