Teen Builds Nuclear Bomb Detector 210
DaneM writes "An enterprising teenage boy named Taylor Wilson, 17, has created a homemade, hand-held nuclear bomb detector. It utilizes a small fusion reactor that he made when he was 14, and detects nuclear materials by shooting neutrons at closed containers and exciting any nuclear materials inside — which, in turn, causes more radiation to be produced, and is detected by the device. This may provide a simpler, more effective alternative to searching containers visually, one-at-a-time. No information is given about how safe such a practice is. Taylor also has some choice things to say about how science is, in fact, very cool."
Re:Skeptical (Score:3, Interesting)
Reality check (Score:5, Interesting)
As someone pointed out: building a fusion reactor, while not trivial, is routinely done by tinkerers worldwide: see e.g. this Instructables guide [instructables.com] .
No, the truly amazing thing here is what I found when I clicked through to the original story [pbs.org] (as usual, not linked in the summary):
Allow me to be the first to say, WHAT THE YELLOW RUBBERY FUCK? In every university department I've ever had experience of, researchers and grad students fight tooth and nail to get funding for anything more expensive than an alligator clip. Meanwhile, these guys have sufficient resources to start handing out equipment and lab space to enterprising teenagers for science fair projects! Hmm, time to start looking for a postdoc position there, I think...
Not sure if good idea... (Score:2, Interesting)
Cross-section to spall neutrons off of U238 or Th232 are ~1barn with halflife of days, but the most common isotope of iron has a n-2n cross section of around half a barn and the result has a halflife of several years. Any nuke techs care to chime in?
Re:No kidding (Score:5, Interesting)
"Fusion reactor" is dumbed-down terminology for the masses. What he's built is probably a Farnsworthâ"Hirsch Fusor [wikipedia.org] which can be made quite small. It's not useful for generating energy as it's very inefficient, but it's a good neutron source. Also, you're missing the point of how his contraption is supposed to work. The radiation detector isn't the part that uses the fusor. The fusor is used to send a neutron beam through the package under test. If it contains enriched uranium or plutonium, the interaction with neutrons will cause it to emit far higher levels of neutron flux and gamma radiation than most other materials. If you see this effect, you might want to inspect the package. I don't know how effective it is in practice, but the premise of operation makes sense.
This could work (Score:5, Interesting)
Read the paper [sciradioactive.com]. He bought or built a "Farnsworth Fusor" to send 2.5 MeV neutrons into a package, and then look for high energy products of neutron induced fission from the package. These would be high enough in energy that the natural background would be quite low, making false positives low. There is no reason why this shouldn't work (although whether its practical is another question.)
He tested it on "20 grams of Natural Uranium Trioxide (UO3) containing - 99.3% U238 and 0.7% U235." (In other words, about 0.1 grams of U235.) The integration time he found he needed was 10 minutes, rather than the 15 seconds desired by DHS, but it's an interesting concept. He doesn't do any calculations as to the expected return from an interesting about of U235 (say, 100 grams), but it would be higher, and so integration times should be less.
He also says that the incident beam is low enough not to be harmful : "the system has low enough does as to not affect the health or functionality of the cargo and operator, However, he doesn't state any dosage information, which I would fault him on if I were grading this paper.
Re:Reality check (Score:4, Interesting)
A lot of funding agencies require a certain amount of your research budget to be spent on "educational outreach." It's likely that someone went "gee, here's a cool way to spend my outreach budget that won't require me to do anything."