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Teen Builds Nuclear Bomb Detector
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."
Must be nice to have your own portable fusion reactor.
Parity: What to do when the weekend comes.
He used his *time machine* to make the nuclear fission reactor. Geez, some people are so cynical !
Built his own fusion reactor...excellent...and also figured out a way to make sure that the resulting neutron flux doesn't turn his carcass into a smouldering ash heap. Bonus.
Well, it didn't detect any bombs, but there weren't any, so it has a 100% chance of getting the answer right when there are no bombs around.
Tabletop fusion reactors have existed since the 1950s - created by Philo T. Farnsworth (who invented television as we know it, and who is paid homage to by futurama). They have never been (and likely never will be) able to produce more energy than it takes to fuse the atoms, thus making them impractical as a fusion *power plant* but a "reactor" nevertheless, and a practical source of free neutrons for research purposes, and projects like this.
As someone pointed out: building a fusion reactor, while not trivial, is routinely done by tinkerers worldwide: see e.g. this Instructables guide .
No, the truly amazing thing here is what I found when I clicked through to the original story (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...
Fusors are a standard neutron source, and they're fairly straightforward to build.
The idea that you could throw hydrogen ions at each other with enough energy to fuse is fairly obvious. It turns out that the obvious ways of doing so are orders of magnitude short of generating net power, but they do generate neutrons.
Okay, you might call it a fusion reactor, but it's just a fusor no matter how you look at it. It could most likely be replaced with any other neutron source, since what drives this is the neutron bombardment and the detection of induced radiation, the source of neutrons doesn't matter.
Also, this is in no way revolutionary. What is revolutionary, however, is that the ICE and border guard hasn't managed to implement an automated neutron scanner yet, but a 17-years-old kid managed to. That is why I congratulate him, and hope the government takes notice of him.
Hyperbole: I use it liberally!
This boy is clearly a genius with unlimited potential. How extraordinarily sad that he is applying all that potential to something as fucking idiotic as counter-terrorism.
Well, there's not much potential use for a fusor in investment banking, so I guess counter-terrorism is where the money is.
Set your phasers on "funky"!
Nope, the bomb's fissile material is subcritical until the point of explosion, when it's compressed by an explosive charge (in crude terms, actually an explosive lens) into supercriticality. While subcritical, no amount of neutron bombardment will trigger it.
Hyperbole: I use it liberally!
You know that you can't set of dynamite that easily. Basicly the whole idea of dynamite is to have an explosive that doesn't blow in your face.
C4 can even be used in some camping stoves to heat your dinner.
"Fusion reactor" is dumbed-down terminology for the masses. What he's built is probably a Farnsworthâ"Hirsch Fusor 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.
Fusion is actually trivial to achieve. Thousands of people have built units in their garage.. it's a common science fair project.
Perhaps you're confused because you've heard that an effective fusion power plant is an area of active research and not currently available and have incorrectly assumed that this somehow implies that fusion must be hard.
You're wrong, and I hope you feel like an idiot now for being so smug.
How we know is more important than what we know.
I assure you, Farnsworthâ"Hirsch fusors exist, fit the dictionary definition of "reactor", are well within the capabilities of teenagers to build, and do emit neutrons.
And I also assure you that when you bombard fissile material with neutrons, its rate of activity goes up, and that increase in activity makes it easier to detect the fissile material with radiation detectors.
The operating principle is given in the second sentence of the goddamn summary: Fire neutrons in, watch radiation from activation products. As others have pointed out, otherwise known as Neutron Activation Spectroscopy.
Well, the article did clearly specify this was a different type of detector, which worked by emitting neutrons, exciting nearby fissionable material, and measuring the radiation given off by it after excitation. Still, it's unlikely the boy has has a portable nuclear reactor. Perhaps some of the article is true, and the journalist confused that part.
Building a fusion reactor ain't so hard. At least as long as you do not care about power input and output.
What science currently has troubles with is to create a fusion reactor with a net surplus of energy after the fusion. That's the thing that's hard. To harness the energy created by nuclear fusion in such a way that the chain reaction can remain stable (i.e. is at the very least self sustaining) is the holy grail of cold fusion power. Not getting atoms to fuse.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Again: Fusing atoms isn't rocket science. Getting more energy out of it than you put in is the nontrivial part.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
The fusion reactor is an neutron emitter is all, not a sustainable power supply that generates more energy than is needed to contain it. It's the second of these that's difficult, even the Sun's containment isn't too great, and at that mass, it has gravity doing a large amount of the work. We need to hold our fusion of levels needed to produce energy in strong magnetic fields to hold it together and not let it melt the reactor. The electromagnets needed to produce such magnetic fields use a lot of energy (until the more recent designs, more than the fusion reaction generates).
If we brainstorm a little we might come up with something. It's worth a try...
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
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
And if he does that trick on a barely subcritical mass of uranium 235 or plutonium, it goes bang.
http://michaelsmith.id.au
At first I thought the article was about this guy, another teenager building a fusion reactor.
Not likely - the amount of fissile material in a typical nuclear bomb has to be compressed to a fraction of its size by the detonation mechanism in order to achieve criticality. Exposing it to neutron flux won't set it off.
Yeah thats why I said a barely subcritical mass, not a normal fission bomb. And yes, I know that this is pretty unlikely. Such a mass would be sensitive to other factors such as humidity.
http://michaelsmith.id.au
Read the paper. 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.
People have accidentally made supercritical masses before. You can't just lump a sufficient amount of plutonium into one spot and magically it's a bomb.
Nope. It'll seriously mess up your day, but a bomb it ain't.
Stefan Axelsson
I can see a group of engineers being told " Okay this kid showed us a plan on how to make this thing you need to figure out how to make it work in the field UNLESS I SHOULD FIRE THE LOT OF YOU AND HIRE THIS KID AND HIS FRIENDS"
maybe the dosage info is not present because he did not have/take the time to get enough data for a legally/medically sound figure??
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Yes i agree, but its not approved knowledge by our federal government. Please come with us.
---- Booth was a patriot ----
Comment removed based on user account deletion
I would guess that it is a Farnsworth-Hirsch fusor which is a commercially produced device to produce free neutrons. In terms of application I'd be a little concerned what this device is used to probe. Neutrons are readily absorbed by many nuclei and can produce radioactive isotopes. So scanning an object will result in making it radioactive. While I would hope the number of neutrons required would be small, and so the activation minimal, this is still probably a concern for foodstuffs since radioactive material is a lot more dangerous inside the body than outside. Same applies for clothing too probably.
The other issue is that since a nuclear device is a sub-critical mass of fissile material bombarding it with enough neutrons may actually make it supercritical while it is in the beam if the beam balances the neutrons lost. This would let you "detect" the bomb put perhaps not in a very constructive way...although again I would guess that the number of neutrons used for scanning would probably be too small to do this.
This process is called neutron activation analysis. It's well known. The practical problems are 1) not putting in so many neutrons that the tested object becomes radioactive, and 2) detecting enough emitted particles in a reasonable length of time. There's an obvious tradeoff there. The second problem is solvable with a large number of detectors, which probably means a portal or tunnel setup, rather than a hand-held device.
Here's a commercial luggage screening machine from Russia which includes nuclear material detection by neutron activation, along with regular explosive detection.
Free as in cats.