Room-Temperature, Small-Scale Fusion at UCLA

gnuman99 writes "A UCLA collaboration (Seth Putterman, Brian Naranjo and Jim Gimzewski) appear to have developed a fusion device powered by a pyroelectric crystal, a type of crystal used in cell phones to filter signals. When heated, such a crystal produces a large electric charge on its surface. The UCLA researchers placed a lithium tantalate (LiTaO3) pyroelectric crystal so that one side touches a copper disc. A tiny tungsten probe is then placed at the center of the copper disc. When the crystal is subsequently heated, a very large large electric field is produced at the end of the tugsten tip, ~25 billion volts per meter. This field gradient is so high that it strips the electrons from nearby deuterium atoms. The ionized deuterium atoms then accelerated by this field towards a solid target of erbium deuteride (ErD2). They collide with it at such high energies that some fuse with the target. A measurement of almost 900 neutrons per second was observed. This is 400 times the background! Although the amount of energy produced in this initial experiment was miniscule (~1E-8 jules), this technology could be used for things like microthrusters. There are pictures and movies on the UCLA's physics site." Reader richmlpdx adds a link to coverage at MSNBC.

Comments

Re:Pyroelectric?

[grmoc]

pyroelectric-- Converts heat energy into electrical energy

piezoelectric-- Converts kinetic energy into electrical energy

In this experiment, they heat up a (Lithium tantalate) crystal which reacts by creating a very high charge.. etc.

In other words, the crystal is a pyroelectric crystal, and not necessarily piezoelectric.

Other contested fusion report

[kebes]

In 2002 there was a report claiming fusion due to cavitation. The article appeared in Science:
Science, Vol 295, Issue 5561, 1868-1873 , 8 March 2002 [DOI: 10.1126/science.1067589]

The method involves irradiating a liquid with sound. The acoustic waves can cause microscopic bubbles to form in solution (cavitation). When these bubbles collapse, their temperatures can become quite high. Done properly, in fact, these cavitations can lead to sonoluminescence (creation of light from sound). The creation of a plasma under these conditions has been confirmed. The Science article further claimed that neutrons were measured, indicating that fusion temperatures had been achieved. They were certainly not claiming this as a power source (yet), since energy input was much greater than output.

The interesting thing is the controversy that resulted, and, as far as I know, is still not resolved. Scientists worldwide are still split on whether or not fusion has really been achieved. It will take some time longer before we know for sure (altough the most recent reports I've read lean towards this really being fusion).

I'm bringing this up because it seems rather similar to what we have here. It is a high-profile announcement of fusion in a rather unusual setup. I anticipate that this will be met with much skepticism (rightly), and that it will take some time before we know "for sure" that it's really fusion.

Anyways, highly interesting results, and I'm looking forward for future confirmation/elaboration of these experiments. But I wouldn't get too excited, since these kinds of discoveries sometimes have subtle flaws (or mis-interpretations) that only become revealled when the full scrutiny of the scientific process is applied to them.

Useful for neutrons, not power (and it's hot)

[radtea]

What these guys have done is found a novel application of a relatively well-known means of generating extremely high electric fields. This is good, and may produce more compact, robust neutron generators than we currently have.

But it is clear from the article--and the basic physics--that this isn't a practical means of generating fusion power. This is just another hot fusion mechanism--it isn't "room temperature". The deuterium ions from the gas discharge are accelerated by the field and smash into the ErD surface with high energies.

The interaction cross-sections are such that virtually all of the D ions will slow down without fusing, and the energy that went into accelerating them will be only recoverable as heat, with the usual thermodynamic (in)efficiencies. The DD fusion cross-section just isn't high enough to overcome those losses.

Cool experiment, though.

--Tom

Re:Takes a lot more energy than it produces

[kebes]

The only other ways to achieve neutron flux (that I'm aware of) are to (1) use a particle accelerator collision to release neutrons (i.e.: spallation) or (2) to use a radioactive source (or running nuclear recator) and guide the flux of exiting neutrons. Both of these are quite large and not very portable.

Although this research is not going to give us energy production, it is the smallest neutron source I've heard of (palm-sized according to article). This in and of itself is quite exciting, and it would have numerous applications in industry. Neutron sources right now are used to image industrial materials (it can be used to map the internal stress distribution in pipes, aircraft components, etc... and it can get images through materials that would block x-rays). Having portable neutron-imagers would be useful to industry for doing stress analysis/imaging on components while they are in actual use. I can think of lots more applications, but I'll leave it at that.

For those interested, here is the abstract of the Nature article in question (the article is already available online, to subscribers, even though it officially releases in tomorrow's issue of Nature):
Nature 434, 1115-1117 (28 April 2005) | doi: 10.1038/nature03575

While progress in fusion research continues with magnetic[1] and inertial[2] confinement, alternative approaches--such as Coulomb explosions of deuterium clusters[3] and ultrafast laser-plasma interactions[4]--also provide insight into basic processes and technological applications. However, attempts to produce fusion in a room temperature solid-state setting, including 'cold' fusion[5] and 'bubble' fusion[6], have met with deep scepticism[7]. Here we report that gently heating a pyroelectric crystal in a deuterated atmosphere can generate fusion under desktop conditions. The electrostatic field of the crystal is used to generate and accelerate a deuteron beam (> 100 keV and >4 nA), which, upon striking a deuterated target, produces a neutron flux over 400 times the background level. The presence of neutrons from the reaction D + D --> 3He (820 keV) + n (2.45 MeV) within the target is confirmed by pulse shape analysis and proton recoil spectroscopy. As further evidence for this fusion reaction, we use a novel time-of-flight technique to demonstrate the delayed coincidence between the outgoing alpha-particle and the neutron. Although the reported fusion is not useful in the power-producing sense, we anticipate that the system will find application as a simple palm-sized neutron generator.

Re:Takes a lot more energy than it produces

[kebes]

muon-catalyzed fusion would only viably occur in a particle accelerator setup, which I already mentioned (where else are you getting the muons from). In any case (as far as I know) no such thing is actually used today at neutron facilities.

For examples of neutron-beamline research facilities that exist today, I refer you to NIST, HMI, and the Spallation Neutron Source (still being built).