The Fifth Conference “ Nuclear Science and Its Application”, 14-17 October 2008
INTRODUCTION
OF
SECONDARY
STANDARD
DOSIMETRY
LABORATORY AND ACTIVITIES
D. YASAR
Metroloji Unit, Secondary Standard Dosimetry Laboratory (SSDL) TAEA-Çekmece Nuclear Research and Training Center, Istanbul, Turkey [email protected]
The SSDL was established in 1983 and is a member of the IAEA/WHO Network of SSDLs. The laboratory has acquired the status of national standard laboratory with the basic aim o f improving accuracy in radiation dosimetry in the country. It is also the national focal point for the calibration of radiation measuring instruments used in radiation protection and radiotherapy. More than 2500 radiation instruments are normally calibrated every year. The laboratory has also the responsibility to ensure that the calibration services provided by the laboratory follow internationally accepted metrological standards. This is achieved by calibrating the laboratory’s protection and therapy levels dosimeters against those in the Primary Standard Dosimetry Laboratories (PSDLs).
External radiation quantity can be measured in terms of exposure, air kerma, absorbed dose, dose equivalent, ambient dose equivalent by using radiation measuring instruments. Various kinds o f radiation measuring instruments such as survey meters, area monitors, personal dosimeters, contamination-monitoring instruments are used in irradiation facilities for radiation protection purposes. Area dosimeters or dose rate meters should be calibrated in terms o f the ambient dose equivalent. In radiotherapy centers, the radiation dosimeters are normally used for determinations of the output of Cobalt-60 teletherapy units and medical linear accelerators (linacs) and should be calibrated in terms of exposure, air kerma or absorbed dose to water. Radiation measuring instruments need to be calibrated to ensure that they give accurate and correct reading with a certain uncertainties. They should be calibrated annually or after major repair.
Key words: Dosimetry, dosimeter, calibration, absorbed dose..
