Encouraged, and armed with this background radiation survey to reduce false alarms, the team is now testing a homemade detector based on a 4-inch by 4-inch by 16-inch sodium iodide crystal, custom grown by Saint Gobain, a subsidiary of Compagnie de Saint-Gobain headquartered in Paris. It is the same technology used in many monitors currently deployed at ports around the country. It will also be used in most of the new Advanced Spectroscopic Portals being purchased by DHS.
"The crystal is like Frodo's sword," explained a Glaros collaborator. "It starts to glow when the bad stuff's around, kind of a blue fluorescence."
Faced with a large-crystal scanner, terrorists would find it extremely difficult to hide 10 kilograms of uranium 235, the amount needed to construct a first-generation Chinese- or Pakistani-designed weapon. To shield it, a terrorist "would have to get a shit load of lead bricks and put the source inside," said Glaros. Theoretically, the device could also detect a Soviet-era, plutonium-fueled suitcase bomb.