Preliminary Study on the Quantitative Value Transfer Method of Absorbed Dose to Water in 60Co γ Radiation

Absorbed dose to water in 60Co γ radiation is the basic physics quantity in the quantitative value system of radiation therapy, it is very necessary for radiation therapy. The study on the quantitative value transfer method of absorbed dose to water in 60Co γ Radiation could provide important technical support to the establishment of Chinese absorbed dose to water quantity system. Based on PTW-30013 ionization chamber, PMMA water phantom and 3D mobile platform, quantitative value transfer standard instrument was established, combined with the requirement of IAEA-TRS398, developed preliminary study of 60Co absorbed dose to water quantity value transfer method. After the quantity value transfer, the expanded uncertainty of absorbed dose to water calibration factor of PTW-30013 was 0.90% (k=2), the expanded uncertainty of absorbed dose to water of 60Co γ reference radiation in Radiation Metrology Center (SSDL of IAEA) was 1.4% (k=2). The results showed that, this value transfer method can reduce the uncertainty of 60Co absorbed dose to water effectively in Secondary Standard Dosimetry Laboratory