1976 Volume 31 Issue 6 Pages 534-538
In recent years, thermoluminescent dosimeter has been studied as the medical dosimetry. Especially it has become to be used widely for personal monitoring. Though there are so many reports about TLD in our conutry, almost all of them are concerned with LiF. This study was tried to detect some fundamental characteristics of Mg_2SiO_4 : Tb and MgB_4O_7 : Tb. The results indicated the followings. 1. Directional dependency of Mg_2SiO_4 : Tb was not observed for 15 MV and 200 kVp X-rays in water, and was negligible for 200 kVp X-rays in air, but for diagnostic X-rays it was about 50% in air. 2. The fading of Mg_2SiO_4 : Tb in the room temperature was not observed at least within 13 days after irradiations. 3. The average of Coefficinet of Variation (CV) of thirty Mg_2SiO_4 : Tb rods, when irradiated in the range of 16.7 mR to 71.45R was nearly 5%. While MgB_4O_7 : Tb, when irradiated in the range of 7.5R to 1,294.5 R was nearly 16%. As a result, it was concluded that MgB_4O_7 : Tb is not so reliable as dosimeter.