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Muon Detector Could Thwart Nuclear Smugglers

Posted by Hemos on from the interesting-applicatons dept.

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."

7 of 54 comments (clear)

  1. Hope it performs better... by 3waygeek · · Score: 4, Interesting

    than what these guys used.

    1. Re:Hope it performs better... by sgant · · Score: 4, Insightful

      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
    2. Re:Hope it performs better... by DustMagnet · · Score: 4, Interesting

      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.

      --
      'SBEMAIL!' is better than a goat!!
  2. Re:Safety by ecotax · · Score: 5, Insightful

    Regardless of how harmful these muons are when passing through your body, there is certainly no *added* harm in this detection method, because the muons used are the ones from space that has passed through you anyhow.

    --
    "Money is a sign of poverty." - Iain Banks
  3. tin foil foiled by Patrik_AKA_RedX · · Score: 4, Funny

    We should have seen it coming: tin foil hats are useless now...

  4. Why muons go straight through by PiMuNu · · Score: 5, Informative

    The reason muons don't stop inside our bodies is because they (a) don't interact with atomic nuclei much and (b) are quite heavy.

    So there are lots of different particles, like protons and neutrons or electrons, that you could use.

    But protons bounce off atomic nuclei because they see something called the "strong force". This means they stop very quickly.

    On the other hand, electrons don't see the strong force, which means they don't bounce off the atomic nuclei much at all. In fact, electrons spend all their time bouncing off the electrons that whizz round the outside of the atom.

    The thing is though that electrons are much lighter than protons, so even though they only see the electrons in the atom, they still bounce right off them. The same goes with photons (e.g. light, x-rays).

    This means that the electrons (and x-rays) get stopped very quickly too.

    So both the electrons and protons get stopped very quickly, which means they deposit much more energy inside you = nasty radiation damage!

    Muons, OTOH, will zip straight through as they don't see the atomic nuclei and are relatively heavy. This means they do less radiation damage, and you need fewer of them.

    This is why you can get away with using atmospheric muons. It also explains why the atmospheric muons are there in the first place - all the other particles get stopped in the atmosphere.*

    *Except some special particles called neutrinos - but let's not go there.

    Here's a general particle physics wikipedia

  5. This looks promising but... by radtea · · Score: 4, Insightful

    ...3% false positives is still orders of magnitude too high for a deployable system. There are a range of interesting things they might do to improve the accuracy.

    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.