@misc{oai:repo.qst.go.jp:00070615,
 author = {Kobayashi, Ikuo and Yajima, Kazuaki and Yasuda, Hiroshi and 矢島 千秋 and 保田 浩志},
 month = {May},
 note = {The Aluminum Oxide had been known well as TLD material for environmental measurement with high sensitivity, small fading, physical stability, but it was difficult to measure easily due to thermal quenching and light fading effect. After that Optically Stimulated Luminescence method could make Aluminum Oxide easy
measurement system. At first stage, the Laser light beam had been used as stimulation source. Currently LED stimulation method had been developed, and which could develop the compact reader, which size is note book, called as microStar, it can be supplied by automobile battery. This study was conducted to understand the characteristic of low dose in order to make sure the capability for environmental measurement use. the dosimeter, which was developed for environmental measurement
(EX), was used, this EX dosimeter is consist of e four elements, open, plastic, copper and copper filters.
Method
We had dosimeters irradiated by 74 GBq and 7.4GBq Cs-137 radiation source in National Institute of Radiological Science in the irradiation condition from 20 micro Gy to 1mGy in air. OSLD is capable for multiple reading, so we have dosimeters read by several readers and compared the result, and had kept them for several weeks, then have the dosimeters read by several readers again. 
Result and Discussion
After 20 micro Gy irradiation, we could observe the significant values,in case of less than 100 micro Gy irradiation, the coincident variation was over 10%, but more than 500 micro Gy, the coefficient variation could become less than 5%. on comparison between each readers, it depends on each reader's noise for low dose, there is no differences between each readers in high dose.
The above conclusion, microStar can be used for environmental measurement, fundamentally micorStar was developed for home land security and potable measurement equipment, so it is important to conduct the performance test and understand the feature of reader, in order to use it as environmental measurement., The Third Asian and Oceanic Congress on Radiation Protection（第3回アジア・オセアニア放射線防護会議）},
 title = {Environmental Radiation Dosimetry by the Small OSL Reader},
 year = {2010}
}