National Geographic

A``````B``````BCD``````D``````D``````D``````Nuclear materialdetected``````Neutrons``````Nuclearisotope``````Photon``````Nuclear materialdetected``````To avoid harmfuldoses of radiation,the driver pulls intothe scanner, parks,and exits beforethe truck is sentthrough the system.``````JASON TREAT AND RYAN T. WILLIAMS, NGM STAFFART: MARK GRASSASOURCE: PASSPORT SYSTEMS, INC.``````When photons strikenuclear material, neutronsradiate outward.``````/RFDWLQJQXFOHDUPDWHULDOAs the 3-D model is being created, adetector D scans the cargo for neutrons,produced when x-rays interact with nuclearmaterial. When the data are combined withthe 3-D model, an operator can pinpointthe location of any nuclear contraband.3