Determination of scanning rate correction factor on the dose rate measured by a dosimeter in motion

Abstract

This study analyzed the scanning rate correction of the dose rate using a mobile dosimeter. An accident at a nuclear power plant exposes nearby residents to external radiation from radioactive nuclides released into the atmosphere. Residents resort to indoor sheltering or evacuate using vehicles according to the disaster evacuation plan. Considering this process, a vehicle-mounted mobile dosimeter was developed to manage the radiation exposure of residents and monitor the dose along the evacuation route. Monitoring the on-site dose along the evacuation route using a mobile radiation detector mounted in a vehicle can cause dose rate underestimation depending on the scan speed. Compensating for the underestimated dose is necessary to determine the risk area from the dose measurement results and ensure greater safety in the process after the secondary evacuation. In this study, MCNP (Monte Carlo N-Particle Transport) 6.2 simulation based on experimental verification using a moving point source was employed to evaluate the degree of dose reduction according to the scan speed, and a function to compensate for the dose reduction was determined.