Nuclear Fusion Discovered

prostoalex writes "Both USA Today and The New York Times are reporting on research group from UCLA led by Seth J. Putterman which has discovered a form of nuclear fusion. The impact of the discovery? 'While the device is probably too inefficient to produce electricity or other forms of energy, the scientists say, egg-size fusion generators could someday find uses in spacecraft thrusters, medical treatments and scanners that search for bombs.' The findings are published in Nature magazine."

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[waldoiverson]

I remember reading an article in Wired back in 1998 that was fascinating. It talked about Cold Fusion, the historical *ahem* problems with theories, and the current research. I am not a physicist but still found this to be informative and interesting. Thanks to the internet, you can still find it here: http://www.wired.com/wired/archive/6.11/coldfusion .html?pg=1

Re:great result, but not really a "discovery"

[Anonymous Coward]

>And I'm afraid it's a little bit of a dodge to
>say it's "at room temperature". The article
>doesn't say this, but presumably this takes place
>in a vaccum, where temperature is basically
>undefined in any conventional sense.

From the NY Times Article:

"In the experiment, the crystal, a cylinder about an inch and a quarter in diameter and a half-inch in length, was mounted inside the footlong cylinder and surrounded by a gas of deuterium, a heavy version of hydrogen."

The problem isn't the (lack of) vacuum, but the 50F heating. 50F + Room Temp != Room Temp. It's a heck of a lot cooler than most fusion, but 100F is where I draw my personal line at the end of the abstract notion of "room temperature" ;)

Re:great result, but not really a "discovery"

[Anonymous Coward]

Sure, its easy for someone to overhype this, but to say it's "not a discovery" seems equally silly. These folks have demonstrated a new means to *produce* fusion. What seems to be promising here is the ability to switch it on and off. The interesting byproduct in this case is not energy (which is negligible) but a controlled source of neutrons. Neutron generators based on high voltage ion accelerators already exist, but are bulky and expensive. The tease in this case is smaller, cheaper neutron generators to combat evil wherever it exists...

homeland security applicatins

[khrtt]

It took me a while to realize what the heck neutron sources might have to do with homeland security. I think what they have in mind is detection of fissile material (i.e. uranium and plutonium, as in nukes).

You irradiate the baggage/cargo (or whatever) with neutrons, and check the outgoing neutron flux with a geigerzahler or some other neutron detector. If there is fissile material in the baggage, some of it would split, generating detectably more neutrons.

If you want to get cute about it, note that fission neutrons have lower energy than fusion neutrons. Then use a neutron detector that can differentiate neutrons by energy.

Now, you can probably detect neutron flux from spontaneous fission without any irradiation, but depending on type of fissile material and amount of shielding that flux might be too low to detect reliably. And you wouldn't be able to tell an isotopic neutron source from fissile materials. Not that isotopic neutron sources shouldn't raise suspicion if found in cargo/baggage.

The only real problem with a detector based on neutron irradiation is that you have to keep people the hell away from it:-).

Re:homeland security applicatins

[Andy Dodd]

Another reply to your post already commented on this, but neutron sources can be used directly for imaging of non-radioactive materials in a manner very similar to X-ray imaging, except that the capabilities of neutraon imaging are far greater. (For example, neutron imaging can find small stress fractures in metals that X-ray imaging cannot find.)

For a few decades, Cornell University ran a low-power fission reactor (unpressurized, approx. 100-200KW output power), and neutron generation for just such imaging techniques was the primary use for the Ward reactor.

Sadly, the reactor, one of the only low-power research reactors in the country, was shut down around 2000-2002. (I can't remember exactly, but it was the last half of my time as an undergrad there.)

Looking down into the containment pool to see the Cerenkov radiation coming from the core below was one of the most amazing sights I will ever see. (Cerenkov radiation is a bluish light that is emitted when a particle travels faster than the speed of light in the medium it travels through. In this case it was neutrons passing through the water at the bottom of the containment pool.)

Re:great result, but not really a "discovery"

[Andy Mitchell]

Muon catalysed cold fusion has looked like a good possibility for decades. However, as far as I'm aware, the problem is that the muons end up sticking to the fusion products too often rather than going on to catalyse the next fusion. As muons are short lived and "expensive" in terms of energy to produce this is not yet a practical source of power.

I seem to recall that in the forward to one of his books (probably 2010, or one of the other 2001 sequels) Arthur C Clarke talks about this as a possible source of power and that he describes it as working best at about 700C. Very cold compared to every other form of fusion that has been conclusively shown to actually work.

Lead into gold ???

[willCode4Beer.com]

I think it would be easier to turn gold into lead.

Gold having an atomic number 79 compared to 82 of lead. Isn't it easier to fuse on extra protons and neutrons with an accelerator than it is to split off just a few. With the atomic weights 197 (Gold) and 207(Lead) You'll need to hit the gold with a hydrogen, a helium, and some extra nuetrons to turn it into lead.
To turn lead into gold, you need a way to strip off this little bit, or split, split, fuse, fuse, and pull out the extra in the middle step.

Just MHO.

I am not a nuclear (or nuclar for those from the red states) physicist. I will not be held responsible if you destroy the planet.

neutrons and cells

[micromuncher]

Though I find the (dup) article very cool, there are a couple things about neutron emitters...

1) as a propulsion source, ion emitters are cheaper/safer
2) from a safety PoV, neutrons don't interact too well with living cells (in any amount) - producing free radicals - almost impossible to shield against

Still smaller

[swordfishBob]

Yes, it's only about creating a controlled stream of neutrons, with a device the size of a toaster. It's a good step forward for that though.

aparatus for identifying unknown substances non-invasively can now be made cheaper and more portable.

Make it smaller still, and perhaps you could swallow a radiation source to treat bowell cancer on the way through, instead of irradiating your whole body from the outside.

Re:great result, but not really a "discovery"

[Goldsmith]

Magnetically confined fusion plamas reached the "break even" point a number of years ago.

The point now is to make a fusion reactor which can get that energy out safely in a useful form for less than $1 billion in hardware. Also, they do inject high temperature ions into the chamber, it would be silly not to.

Finally, if you think expensive and complicated are what get physicists prestige, you don't know enough about physicists.