Perimeter Radiation Monitors

Radiation portal monitors (RPMs) have uses in a wide variety of application spaces. Certain facilities, such as scrap metal processing plants, use RPMs to screen all incoming feed material to protect their facility, workers, and product from scrap metal contaminated with radiation sources that can include orphan industrial or medical radiation sources. In the nuclear security arena, RPMs are frequently used to screen people, vehicles, and cargo containers as they enter or exit a country via a land border crossing, an international airport, or a seaport. At nuclear facilities, perimeter radiation monitors are located at the periphery of nuclear-material and radioactive-contamination control areas to detect accidental or covert removal of radioactive materials. This chapter discusses various applications of perimeter monitors and gives primary emphasis to RPMs used to screen for material found out of regulatory control.