MEASUREMENT OF DAILY ENVIRONMENTAL RADIATION-DOSES USING HYPERSENSITIVE THERMOLUMINESCENCE MATERIALS

Lower detection limits below I mu Gy have been reported for the hypers ensitive thermoluminescence phosphors such as LiF:Mg,P,Cu and alpha-Al 2O3:C. Considering that usual daily environmental doses are in the ran ge of 1-5 mu Gy, the CIEMAT Dosimetry Unit has designed an experiment to validate the real capability of these dosemeters to assess extremel y low doses in two different environmental situations (indoor, outdoor ). Three types of these phosphors (GR-200A from China, MCP-N from Pola nd, alpha-Al2O3:C from Russia) and one electronic dosemeter EPD from S iemens-Plessey have been studied. The experiment consisted of the dete rmination of the integrated dose after exposure periods to environment al radiation ranging from one day to six months. These measurements we re carried out with each one of the systems using a high pressure ioni sation chamber as a reference instrument. The results demonstrate that the hypersensitive phosphors are capable of estimating these very low doses in agreement with the active detector.