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Muon Detector Could Thwart Nuclear Smugglers
Ben Sullivan writes "Cosmic rays that bombard Earth could help catch smugglers trying to bring nuclear weapons into the U.S. Los Alamos scientists say they've developed a detector that can see through lead or other heavy shielding in truck trailers or cargo containers to detect uranium, plutonium or other n-bomb materials. Their technique, muon radiography, is reportedly far more sensitive than x-rays, with none of the radiation hazards of x-ray or gamma-ray detectors now used at border crossings. From Science Blog."
Yeah, right. It will harmlessly pass through a bag of water like a human body, because water is such a lousy material at stopping radiation. That's why it's not used in nuclear reactors or cosmic ray detectors...
Of COURSE they're going to have this on the news and general media...they will certainly play up "hey, we have detection equipment so sensitive that it picked up on someone getting radiation treatment".
It's a propaganda tactic, play up that they can detect almost anything to make the bad guys think twice in trying to slip something in undetected. Since plutonium etc is hard to get as it is, perhaps the bad guys wouldn't want to risk losing it so easily (the risk here is losing the plutonium, not "getting caught" as human life means nothing to them as they've shown over and over).
"Leo Fender was in a 'state of grace' when he designed the Stratocaster." -- Paul Reed Smith
Remember when they couldn't find that lost nuclear weapon right off our shoreline for, like, damn near years? Inpenetrable detection net my ass. There could be a lot of material moving in and out and we might never know it.
The same people who buy that silly SDI crap believe this too.
The natural move from my point of view is to look at mu-N interactions, where a muon blows apart a nucleus in the target material, producing a shower of excited nuclear fragments and neutrons. Heavy materials such as plutonium will have a much different cascade signature than relatively light things like iron, so it may be possible to develop a quite specific finger-printing mechanism that would be hard to work around. With a muon detector on top to act as a trigger, and some combination of gamma and neutron detectors nearby, this is might be able to both speed up processing and improve accuracy dramatically.
Of course, terrorists could always fall back to the obvious plan B: smuggling the weapon in hidden in a bale of marijuana.
--Tom
Blasphemy is a human right. Blasphemophobia kills.
You can't trust what MissileThreat.com says about missile threats. Every page declars they're promoting SDI. They're interested in contracts, not truth.
--
make install -not war
At ground level muons are about the only thing you can use for this purpose because the other particles you mentioned (protons, neutrons, and electrons) do not have appreciable penetrating energy because they are all interaction products. Neutrinos, as you alluded to, interact so weakly that they are both too tough to detect, and for the same reason they wouldn't make very good probe particles. Ground-level muons are routinely used to calibrate cosmic ray detectors, except for the neutrino detectors which are located deep underground to get away from atmospheric muons.
By the way, muons have been used as probes before. The most fameous example was searching for hidden chambers in the Great Pyramid of Chefren. Apparently they're still doing it today.
Muons are the most dominant charged particle in terms of flux on the ground not because they they can travel longer through the atmosphere, but because when a high-energy primary proton comes barrelling through the atmosphere it knocks off lots of pions in the downward direction that then decay into high energy muons. For every one proton that initiates such a particle shower, you get many many muons.