Public release date: 27-Jan-2006
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Contact: Jason Gorss
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Rensselaer Polytechnic Institute

New sonofusion experiment produces results without external neutron source
A team of researchers from Rensselaer Polytechnic Institute, Purdue University, and the Russian Academy of Sciences has used sound waves to induce nuclear fusion without the need for an external neutron source, according to a paper in the Jan. 27 issue of Physical Review Letters. The results address one of the most prominent questions raised after publication of the team's earlier results in 2004, suggesting that "sonofusion" may be a viable approach to producing neutrons for a variety of applications.
By bombarding a special mixture of acetone and benzene with oscillating sound waves, the researchers caused bubbles in the mixture to expand and then violently collapse. This technique, which has been dubbed "sonofusion," produces a shock wave that has the potential to fuse nuclei together, according to the team.

The telltale sign that fusion has occurred is the production of neutrons. Earlier experiments were criticized because the researchers used an external neutron source to produce the bubbles, and some have suggested that the neutrons detected as evidence of fusion might have been left over from this external source.

"To address the concern about the use of an external neutron source, we found a different way to run the experiment," says Richard T. Lahey Jr., the Edward E. Hood Professor of Engineering at Rensselaer and coauthor of the paper. "The main difference here is that we are not using an external neutron source to kick the whole thing off."

In the new setup, the researchers dissolved natural uranium in the solution, which produces bubbles through radioactive decay. "This completely obviates the need to use an external neutron source, resolving any lingering confusion associated with the possible influence of external neutrons," says Robert Block, professor emeritus of nuclear engineering at Rensselaer and also an author of the paper.

The experiment was specifically designed to address a fundamental research question, not to make a device that would be capable of producing energy, Block says. At this stage the new device uses much more energy than it releases, but it could prove to be an inexpensive and portable source of neutrons for sensing and imaging applications.

To verify the presence of fusion, the researchers used three independent neutron detectors and one gamma ray detector. All four detectors produced the same results: a statistically significant increase in the amount of nuclear emissions due to sonofusion when compared to background levels.

As a cross-check, the experiments were repeated with the detectors at twice the original distance from the device, where the amount of neutrons decreased by a factor of about four. These results are in keeping with what would be predicted by the "inverse square law," which provides further evidence that fusion neutrons were in fact produced inside the device, according to the researchers.

The sonofusion debate began in 2002 when the team published a paper in Science indicating that they had detected neutron emissions from the implosion of cavitation bubbles of deuterated-acetone vapor. These data were questioned because it was suggested that the researchers used inadequate instrumentation, so the team replicated the experiment with an upgraded instrumentation system that allowed data acquisition over a much longer time. This led to a 2004 paper published in Physical Review E, which was subsequently criticized because the researchers still used an external neutron source to produce the bubbles, leading to the current paper in Physical Review Letters.

The latest experiment was conducted at Purdue University. At Rensselaer and in Russia, Lahey and Robert I. Nigmatulin performed the theoretical analysis of the bubble dynamics and predicted the shock-induced pressures, temperatures, and densities in the imploding bubbles. Block helped to design, set up, and calibrate a state-of-the-art neutron and gamma ray detection system for the new experiments.


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The research team leaders are all well known authorities in the field of nuclear engineering. Lahey is a fellow of both the American Nuclear Society (ANS) and the American Society of Mechanical Engineers (ASME), and is a member of the National Academy of Engineering (NAE). Block is the longtime director of the Gaerttner Linear Accelerator (LINAC) Laboratory at Rensselaer, and he is also a fellow of the ANS and recipient of their 2005 Seaborg Medal, which recognizes an individual who has made outstanding scientific or engineering research contributions to the development of peaceful uses of nuclear energy. Taleyarkhan, a fellow of the ANS and the program's director, is currently the Ardent Bement Jr. Professor of Nuclear Engineering at Purdue University. Nigmatulin is a visiting scholar at Rensselaer, a former member of the Russian Duma, and the president of the Bashkortonstan branch of the Russian Academy of Sciences (RAS).

About Rensselaer
Rensselaer Polytechnic Institute, founded in 1824, is the nation's oldest technological university. The university offers bachelor's, master's, and doctoral degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research conducted in a wide range of fields, with particular emphasis in biotechnology, nanotechnology, information technology, and the media arts and technology. The Institute is well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.

Keep our fingers crossed

So that movie with Keanu Reeves was right?

What movie?

Quoted: So that movie with Keanu Reeves was right?

Bill & Ted?

I won't believe it until it's published and reproduced independently.

Quoted: So my ex girlfriend is the source of the world's power problems?

No, my ex-wife is.  Hopefully, you and I aren't talking about the same person.

memo to self:

don't ever fart in Acetone.

That sounds "cool"




Get it? - little nerd joke there.

Ha ha

Cold Fusion.





anyway - tag

Quoted: memo to self: don't ever fart in Acetone.

 

Quoted: I won't believe it until it's published and reproduced independently.

It is published, in the next Physical Review Letters

However, it will probably be a while after that before anyone can assemble and complete a experiment.

Just juddging from Rensselaer's own history with this project, designing, setting up, running, analysing, and then writing takes a minimum of two years.

Quoted: What movie?

Chain Reaction

Quoted: Quoted: What movie? Chain Reaction

another movie where someone tries to outrun the explosion

I hope this is really true.

Quoted: I hope this is really true.

What?  Nuclear fusion or that someone can outrun an explosion????

Quoted: Quoted: I hope this is really true. What?  Nuclear fusion or that someone can outrun an explosion????

Even it it is true, it doesnt mean you can make a power plant out of it.  It may not scale.

People have been building table top fusion reactors using the Farnsworth-Hursh Inertial-Electrostatic Confinement method for 40 odd years.  It has not led to a breakthrough in fusion for electrical power production yet.  It doesnt scale up.  You try to ramp up power and the cathode vaporises.

I'm an RPI student. Kind of nice to see my school is making a name for itself.

RPI has a nuclear reactor on campus for research purposes. We do have a lot of research in nuclear physics so I would give credit to the research team. They certainly corroborate with other capable universities and institutes. After the cold fusion debacle from the 80s, universities and researchers are much more sensitive to publishing results they can't stand on.

But you're prudent in waiting for confirmation from a seperate third party. If sonofusion is real, the next question is how to apply abstract, laboratory stuff in a useful, practical way to get more juice out than we put in.

Quoted: Quoted: I hope this is really true. What?  Nuclear fusion or that someone can outrun an explosion????

Out running explosions of course.  

Quoted: Quoted: Quoted: I hope this is really true. What?  Nuclear fusion or that someone can outrun an explosion???? Out running explosions of course.

Well, I agree then!