Particle Physics To Aid Nuclear Cleanup

mdsolar sends this report from Symmetry Magazine: Cosmic rays can help scientists do something no one else can: safely image the interior of the nuclear reactors at the Fukushima Daiichi plant. ... [M]uon tomography is similar to taking an X-ray, only it uses naturally produced muons. These particles don't damage the imaged materials and, because they already stream through everything on Earth, they can be used to image even the most sensitive objects. Better yet, a huge amount of shielding is needed to stop muons from passing through an object, making it nearly impossible to hide from muon tomography. ... By determining how muons scatter as they interact with electrons and nuclei within the item, the team's software creates a three-dimensional picture of what's inside. ... To prove the technology, the Los Alamos team shipped a demo detector system to a small, working nuclear reactor in a Toshiba facility in Kawasaki, Japan. There, they placed one detector on either side of the reactor core. "When we analyzed our data we discovered that in addition to the fuel in the reactor core, they had put a few fuel bundles off to the side that we didn't know about," says Morris. "They were really impressed that not only could we image the core, but that we also found those bundles."

Comments

Nifty.

[GarethIwanFairclough]

I'm normally pretty mean to particle physicists, but this gear seems pretty nifty. More good info about something is rarely a bad thing.

Bullshit meter off scale

[Anonymous Coward]

These particles don't damage the imaged materials and, because they already stream through everything on Earth

That is some bullshit and whoever wrote this summary must be joking.

Muons are produced by high energy collision in the upper atmosphere. Muons (heavy form electrons) can have more than 1 TeV energy. To say "the don't damage anything" is the most retarded statement in the world. They are one of THE principal reasons for cosmic radiation at ground level. If people were transparent, you could detect 1+ muon exploding inside you. And you'd also see a nice trail of ionized flesh along its entire path.

How do I know? I've measured muons in my undergrad physics class. We used a few centimeters of lead to stop them (ones with specific energy rage, of course) and then measure their lifetime.

Fun tidbit - it's one example of Special Relativity that we can detect them at ground level at all.

Anyway, getting back to the damaging bits, they are much more dangerous than any few Bq of Cesium you eat. But hey, "natural radiation" can't be bad! Only the stuff people make must be, right? right? Too bad there is no difference.

Dr. Manhattan

[PopeRatzo]

I get the feeling there's a superhero origin story somewhere in all this "Let's bombard active nuclear fuel rods with muons and see what happens".

Re:Dr. Manhattan

[wierd_w]

except active mouons of sufficient energy are unlikely to be emitted on the fly. A mouon has a life expectency of some few dozen milliseconds, tops.

The reason that we have mouons from the sun this far into our atmosphere?

The mouons are created when highly energetic protons and iron nucleii from the solar wind hit our upper atmosphere. (Collisions many times more energetic than anything currently being done at CERN), and these resulting mouons have a significant imparted inertial energy behind them-- they come into being traveling at relativisitc velocities. So, for them, a few dozen miliseconds pass before they decay-- but to us, they exist for several dozens of seconds. Long enough for them to come streaming down from the sky in an endless daylight barrage of partical radiation.

Mouons that come into being from fission decay reactions arent quite as energetic-- but still useful for imaging purposes. However, being less energetic, they dont live as long to outside observers, like us.

What am I getting at here?

Dr Manhattan is unlikely to come into being from energetic mouons interacting with fissile reactor fuel rods. Transporting said fuel rods by air exposes them to shittons of them. So far, no superheros have been born this way. :D

Re:Dr. Manhattan

[radtea]

Mouons that come into being from fission decay reactions arent quite as energetic-- but still useful for imaging purposes.

There are (almost) no muons produced by fission. Fission events produce energies of around 200 MeV. Muons have a mass of just over 100 MeV. The phase space available for muon production is essentially nil because so much energy is almost always carried away by the fission products. Basically, to make a muon you have to have everything else stand still. The production rate isn't quite zero, but is close enough to it to not matter.

The technology they are using in this case is to look at cosmic ray muons passing through the reactor core. Similar technology was used to look for undiscovered chambers in Egyptian pyramids in the 80's, if memory serves: cosmic ray muons have ridiculous amounts of energy (they are the bane of neutrino physicists because no matter how deep the lab the muon signal is still appreciable, even under a kilometer or rock. SNO, which is one of the deepest labs in the world, is 2 km down and muons are still detectable, although only at rates of a few per day if memory serves.

Re:They can't pass through everything ...

[wierd_w]

Mouons are interesting things. Too bad that they need to have tremendous energies behind them to exist for any useful period of time-- As you have pointed out, they can and do cause damage.

It would be nice if they were more easily contained and or directed; Mouon induced fusion would be a very interesting thing to explore if focused high energy mouons were a thing.

http://en.wikipedia.org/wiki/M...

Firing such a beam through some hot water would be a very interesting thing indeed.