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."

Hope it performs better...

[3waygeek]

than what these guys used. [10news.com]

Troy Hurtubise might help

[Anonymous Coward]

Troy, inventor of such far-out yet functional devices like the bear encounter suit and fire paste, has finally flipped out [baytoday.ca], or maybe he's on to something.

Re:Hope it performs better...

[Nuffsaid]

Lesson learned. Next time you try to smuggle radioactive material through a border, send someone who verifiably has had recent radioactive treatements.

Customs officer: It's OK, we checked with your doctor. You can bring in that... uh... strange glowing giant lead cat toy!

Re:Hope it performs better...

[DustMagnet]

False alarms are a huge problem with any detection system. I had a coworker stopped while entering the U.S. because they detected explosive residue. He'd been working with explosives for months. The residue level was so high they couldn't get the machine clean again. It kept detecting explosives without any sample. It cost a lot of people a lot of time to verify that he was safe.

Re:Why muons go straight through

[gumbi west]

Oops, muons [wikipedia.org] are leptons [wikipedia.org] just like electrons [wikipedia.org] . They have electric charge and interact with electrons via the electromagnetic force. As such, at relativistic velocities (which they are at, otherwise their half life would prevent them from descending so far into the atmosphere) they act as "minimum ionizing particles" and deposit about 2 MeV per cm^2/gram. multiply the density of an object and its track length and you will get about the amount of energy a meuon will give up while traversing it. For lead (density of about 12 g/cc), at 3 GeV, a muon will go about 4 feet in lead (it's an approximation, so being off by almost exactly the proverbial sqrt(2) from what is in the article almost proves I'm right).

Anyway, the reason muons are so penetrating is that they have so much energy to start with, so they can afford to give it up slowly.

BTW, as a coarse approximation, at sea level, cosmic background is about 1/3 x-rays and electrons, perhaps 1/6 neutrons and the balance is muons. That is by dose, not flux.