Dose measurement of 90Sr source for radiation chemical reaction.

The irradiation characteristics for a plate source of 90 Sr 222GBq (6 Ci) were examined with the blue cellophane dosimeter and the thermoluminescence dosimeter. The 90Sr source used has the active area of 35x20mm2 and the surface concentration of 31.5 GBq (0.85 Ci)/cm2. The high dose rate of 1.1 kGy (1.1x10(5) rad)/h was obtained at the distance of 5 cm from this source. At that time, the isodose curve determined by the blue cellophane was similar to a circle. The peak in depth dose curve was fairly displaced to the shallow direction in comparison with that obtained from the irradiation with an electron beam accelerator (2 MeV). The calculated dose rate attains to 800 kGy (i.0x10(7) rad)/h at the distance of 5 cm from the source when the infinite plate source with the maximum surface concentration (1.51 TBq(40.7Ci)/cm2) is placed on a plane.