Application of 90Sr for industrial purposes and dose assessment

Abstract Typical industry set-up, used for material thickness inspection and process monitoring of different manufactured products, is based on the detection and counting of particles emitted by the radioactive source after passing the inspected material. The sensitivity of this method for determining material thickness in the flooring industry is assessed in this paper with Monte Carlo method by simulating a simplified typical industrial set-up used for this purpose. From the results of the Monte Carlo simulations, the sensitivity corresponding to the changes in the number of the detected electrons for the thickness material in range 2–2.2 mm was obtained. It was found that it is possible to distinguish the number of detected electrons in the 3σ region for the thickness changes of order of 0.1 mm, proving the necessary sensitivity of the presented method and adequacy as a part of quality assurance procedure. Furthermore, due to radioactive source use in this type of measurements, it is necessary to estimate the dose received from ionizing radiation. Thus, ambient dose equivalent was measured several times during the production line, at the nearest position to the radioactive source reachable by hand, but also at the position of the operator. Measured dose equivalent rate was compared with absorbed dose rate to the extremities obtained by Monte Carlo simulations showing good agreement. Estimated annual equivalent dose to the extremities and annual effective doses confirmed the safe use of the radioactive source 90Sr for the thickness inspection and production process monitoring in the flooring industry.