Dose control in semi industrial irradiation plant at the Ezeiza Atomic Center

In 1975 a study was initiated at the Division of Dosimetry to develop a technique and a system of dosimetry to be applied to the radiosterilization processes in the semi industrial irradiation plant of Ezeiza Atomic Center. The result of this study was the potassium nitrate/nitrite dosimeter used as routine dosimeter for control processes in food conservation, with a dose range of 0.2 kGy-1 kGy and in radiosterilization processes of disposable medical products of 1 kGy-150kGy. The potassium nitrate crystals undergo a radiolytic reduction. A linear correlation between the dose applied to the solid and the production of potassium nitrite was observed. After the irradiation of solid, the produced nitrite solution is colorimetrically titrated by measuring the absorbency in a spectrophotometer at 504 nm. The color is due to the formation of a diazonium salt and its later copulation with N-1 naphtylethylendiamine hydrochloride in acid medium. In 1980 a postal survey was organized presenting this dosimeter to standardize the irradiation dose in industrial process for Latin America. This dosimeter was presented in 1984 at the International Symposium on High Doses of the IAEA that took place in Vienna. Since them, comparative studies were performed between this dosimeter and those internationally considered and accepted: cerium(IV)/cerium(III) sulphate, ionization chamber of parallel plates, alanine. The results of comparison with the alanine dosimeter, which was used by Dr. Regula of the GSF of Munich, were the following: February 1985: 0% deviation; February 1986: 0.43% deviation. (Author)