Neutron dosimetry with a calorimeter

Abstract

A calorimeter has been used to measure the absorbed dose in tissue from a beam of fast neutrons. The calorimeter is of the twin type and is made of tissue-equivalent plastic. The calorimeter was calibrated electrically using the electrical resistivity of the plastic. The partial dose due to gamma -radiation was measured separately with photographic film in order to derive the neutron dose alone. The results were compared with those found using ionization chambers. Satisfactory results were only obtained after pre-irradiation of the plastic by at least 100 krad of electrons. The accuracy obtainable by the calorimetric method seems similar to or slightly better than that obtainable with ionization chambers.