Fundamental Characteristics of Thermoluminescent Dosimeter.

In recent years, thermoluminescent dosimeter has been studied as the medical dosimetry. Especially it hasbecame to be used widely for personal monitoring. Though there are so many reports obout TLD in our country, almost all of them are concered with LiF. This study was tried to detect some fundamental characteristics of Mf2SiO4 : Tb and MgB4O7 : Tb. The results indicated the follwings. (1) Directional dependency of Mg2SiO4 : Tb was not observed for 15 MV and 200kVp x-rays in water, and was negligible for 200 kVp x-rays in air, but for diagnostic x-rays it was sbout 50% in air. (2) The fading of Mg2SiO4 : Tb in the room temperature was not observed at least within 3 days after irradiations. (3) The average of Coefficient of Varrition (CV) of thirty Mg2SiO4 : Tb rods,when irradiated in the range of 16.7mR to 71.45R was nearly 5%. While MgB4O7 : Tb, when irradiated in the range of 7.5R to 1294.5R was nearly 16%. As a result, it was conclude that MgB4O7 : Tb is not so reliable as dosimeter.