Naturally occurring radioactive materials and medical isotopes at border crossings

Countries around the world are deploying radiation detection instrumentation to interdict the illegal shipment of radioactive material crossing international borders. Some cargo contains naturally occurring radioactive material (NORM) or technologically enhanced NORM (TENORM) that triggers alarms at border crossings. This paper discusses experience with radiation portal monitors for the interdiction of radioactive materials and the issues raised by NORM. The results of observations and computations related to NORM characteristics are discussed.