Improving Monitoring of Radiation Pulses at the Industrial Facilities

Abstract

In case of accidents at the industrial facilities, where there are devices that are a source of ionizing radiation, a significant part of the fission products is in a vaporous and aerosol state. There is no sharp drop in the radiation levels, which means that the terrain can be damaged for a long time and become uninhabitable. To assess the damage and eliminate the consequences of exposure to a hard radiation pulse, it is required to have such systems that register the dose fields in real time with a high temporal resolution and do not require regular verification and reference to the reference fields. To solve the problem, it is proposed to measure the dose rate of pulsed radiation by the induced conductivity in the air. This makes it possible to obtain the absolute values of the dose rate without reference to the reference fields, with a time resolution of 1·108 per second. The relationship between conductivity of the ionized air and the dose rate is given by means of experimentally determined constants: mobility of the electrons in the air and the lifetime of electrons before they stick to oxygen molecules in the air considering participation of the third particle. Proposed method is based on the microwave sounding of the highly ionized air. This allows to significantly expand the range of application of the ionization methods up to 1·108 Sv/s for photon radiation and to provide nanosecond time resolution. In the present experiments, the time dependence of the dose rate on time obtained by high-frequency probing was measured, and the dose per pulse was found by integrating over time. Measurement results were compared with the readings of a certified integral thermoluminescent dosimeter based on LiF. Measurement results indicate agreement within 20–30 %. High-frequency detectors can be used as part of information and measurement systems to alert about possible emergencies. The method allows obtaining final information in real time and forming management teams on mitigation of emergency situations consequences.