Image from U.S. Customs and Border Protection, a bureau of the United States Department of Homeland Security, showing the hidden contents of a truck trailer that wouldn’t be visible by looking in the back door.
More than two billion tons of cargo pass through ports and waterways in the United States every year. Many of these ports rely on cobalt-60 scanners for cargo screening. Because of the radioactive nature of cobalt-60, the industry is leaning toward the use of high-energy X-rays generated by particle accelerators. Improved accelerator and detector technology could be used to detect threats, such as special nuclear material (SNM) or weapons in ship-borne cargo containers and at stand-off distances before the materials enter U.S. ports.
Electron beam accelerators produce higher energy X-rays, which can penetrate deeper than existing systems and provide more information about the nature of the cargo. High-intensity X-rays are imperative for active interrogation methods for SNMs such as photo-fission, delayed neutron and gamma measurements, pulse-shaped discrimination and nuclear resonance fluorescence.
At present, electron beam accelerators reside in a fixed location. Development of new technology at Fermilab allows for the construction of efficient, compact, high-power, high-energy accelerators that enables increased and portable cargo scanning. These systems can produce high-quality X-ray images and initiate more sensitive interrogation for SNM.