Dosimetry of Fission Neutrons and Gamma-Rays from Nuclear Reactors by Paired Fricke Solutions

Abstract

It is found that the heavy-water Fricke solution showed lower sensitivity to fission neutrons (G-value of 3.7) but higher sensitivity to r-rays (G=l6.3) than the light-water Fricke solution (G=5.6 for neutrons; G=l5.4 for r-rays). Using these differential G-values of the paired solutions and the basic principles of Fricke dosimeter, the following paired equations were derived for the heavy-water and the light-water solutions that were exposed to neutron-gamma mixed radiation; DN=1,400A-1,200A' and D 0 =460A'-270A, where DN and Do are the absorbed doses of neutrons and r-rays in the light-water solution, respectively, and A and A' are absorbance increases in the light-water and the heavy-water solution, respectively. The validity of the paired equations was tested by exposure of the paired solutions to the mixed fields of nuclear reactors at Kinki University and Musashi Institute of Technology. Obtained pairs of DN and Do values agreed reasonably well with those measured by paired ionization chambers.