Distributed Fiber-Optic Calorimetric Dosimeter

A novel distributed fiber-optic calorimetric dosimeter is presented. The dosimeter sensors are thermally insulated spherical beads (calorimetric sensors) made of lead mounted on an optical fiber in constant steps. Under gamma radiation exposure, due to the calorimetric effect, the temperature of the beads increases proportional to the dose rate of the radiation. The temperature of the sensor is measured using a stimulated Brillouin scattering analyzer, which makes it possible to obtain the dose rate distribution over the entire length of the optical fiber at distances of up to several tens of kilometers. The results of the experiment confirm the linear nature of the dependence of the sensor temperature on the dose rate with a factor of 0.0027 °C h/Gy. The working range of the experimental sample of the dosimeter is shown to be limited to approximately 315 Gy/h–81 kGy/h. The upper limit of the working range is determined by the melting point of the polystyrene foam which is used to insulate the point sensors. This could be improved by utilizing more heat-resistant materials.