Since 1993, the International Atomic Energy Agency (IAEA) has tracked reported incidents of illicit radioactive material trafficking in their Incident and Trafficking Database. Between 1993 and 2021 there have been 320 recorded incidents of malicious trafficking that included industrial radioactive sources, special nuclear material, and scam/fraudulent material. In order to detect and intercept the illicit movement of radioactive material, countries have developed radiation detection regimes at border crossings and at ports of entry. The chapter discusses the key concepts behind radiation detection at borders, highlighting the commonly deployed defence-in-depth security strategy that utilizes multiple different types of detectors. These detection systems range in size from large, fixed-location radiation portal monitors (RPMs) to hand-held instruments such as personal radiation detectors and radioisotope identification devices. Typically, RPMs monitor moving vehicular and pedestrian traffic and the hand-held systems are employed to isolate and identify radioactive sources registered by the larger systems. With a properly trained force, these radiation detection systems can be effective at detecting the illicit transport of radioactive material across points of entry at borders.
