Shielding Structure Design of ⁹⁰Sr Isotope Radiation Source

The bremsstrahlung spectrum on the surface of a ⁹⁰SrTiO₃ ceramic radiation source was computed by using MCNPX on the base of the designed structure of the ⁹⁰Sr radioactive source. The distribution of the dose equivalent was calculated and analyzed. The results showed that the average photon flux was 1.2×10¹⁰ cm^-2•s^-1 on the surface of the radiation source, and the minimum dose equivalent rate of the surface was 20 Sv/h. By using 7 cm tungsten as the shielding structure, the maximum dose equivalent was 1.35 mSv/h on the surface and 0.027 mSv/h at 1 m below the surface. So the shielding material and structure designed meet the limit of radiation dose equivalent during the transportation.