With the radiation sources widely used in the field of industry, agriculture, medicine, and resources all over the world, the occurrences of the lost and theft incidents are not unusual. There will be great threats to human health and environment for uncontrolled sources. It can be even worse when they are used by terrorists as weapons in the city, such as RDD, which would disperse the radioactive substances into the environment and have a long-term negative impact on human society. Besides the security control and surveillance of radiation sources, the source-searching method using radiation detectors is also needed to find the lost or stolen sources. In the case of radiation monitoring in a city, a mass of people with detectors are needed to cover the large area, while radiation dosimeters are appropriate for its portability and economy.
In this paper, a simple approach to finding and locating unknown radiation sources, which might be in static or mobile condition, using distributed mobile radiation dosimeters is put forward. This approach is able to estimate the time-dependent sources location and the intensity with the dose rate measurements over time periods.
Random data is introduced to verify the approach. Virtual radiation sources and detectors with random movement are created in the cases and the dose rate measurements are computed accordingly, with which sources location and intensity are estimated, where natural background radiation and the statistical fluctuation of measurements are taken into account. The results of the estimated sources show a good consistency with the assumptions.