Writing in Wired Steven Johnson has written an article about efforts underway to detect nuclear weapons in vehicles being driven into cities:
Then there's the more pressing issue: How easy would it be to subvert the network? After the scanning demo in Massachusetts, I sit down in a conference room with Callerame, and he walks me through the physics of concealment. High atomic-weight materials like lead can block gamma radiation, but the large quantities of lead that would be needed would show up on other scanning devices. Callerame's solution is to combine radiation sensors with advanced X-ray technologies, like the backscatter system that produced the startling image of the Mercedes. "I still think you're going to have to X-ray these things," Callerame says. "If you run only a radiation detector and somebody shields their source well enough, you may not pick it up. On the other hand, if you're simultaneously doing X-ray imaging, you'll see this big blob in the middle of the cargo, which would be a dead giveaway of something being clandestinely brought in." He shows me printouts of scans done at a demo in Washington, where they concealed the radioactive material in a container of lead the size of a bowling ball. In the image, the lead container pops out immediately, a bright-white circular shape in the middle of translucent grays. "Now, I should mention, even though we wrapped the cesium in this lead casing, we still managed to pick up the gamma radiation. It's just easier when you do the two in combination."
But a ship carrying a nuke could make it into a harbor and blow up before its cargo was scanned.
|Share |||Randall Parker, 2002 October 21 12:23 PM Dangers Tech Terrorism|