What type of detection do Radiation Portal Monitors utilize?

Radiation Portal Monitors utilize passive detection. This method is effective for identifying radioactive materials because it involves the detection of radiation emitted from sources without the need for an active signal or interrogation. Passive detection systems, such as Radiation Portal Monitors, continuously scan the environment and measure any radiation that is naturally emitted by isotopes present in items passing through or near the monitor. This approach is key in security contexts, particularly at ports and checkpoints, where it allows for continuous and unobtrusive monitoring of cargo and individuals to ensure safety and compliance with regulations regarding radioactive materials.