Not-Fake Cold Fusion

I regret my failure to post on this news sooner, but thought an item this important worthwhile even a delayed. I discovered via Slashdot Science that Christian Science Monitor reported earlier this month that scientists at UCLA have achieved cold fusion...really. The result was published in Nature, the top-ranking scientific research journal. (If you need some background, LBL has a basic explanation of fusion in general)

The Nature's popular summary describes the experiment:

Now Putterman, a physicist at the University of California, Los Angeles, has turned a tiny crystal into a particle accelerator. When its electric field is focused by a tungsten needle, it fires deuterium ions into a target so fast that the colliding nuclei fuse to create a stream of neutrons.

Putterman is not claiming to have created a source of virtually unlimited energy, because the reaction isn't self-sustaining. But until now, achieving any kind of fusion in the lab has required bulky accelerators with large electricity supplies. Replacing that with a small crystal is revolutionary. "The amazing thing is that the crystal can be used as an accelerator without plugging it in to a power station," says Putterman.

The scientific article's abstract downplays the power genering possibilities:

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.

(I know you were pining for a portable neutron source just the other day...)

I wonder if the pessimism about power generation is technically warranted. A quick look over the scientific article doesn't explain why the authors conclude so. Certainly it would be surprising if the reacion itself were self-sustaining, since each trigger particle is injected separately, but I wonder if energy drawn from ejected particles could be channeled back into trigger-particle acceleration to make it effectively self-sustaining. (There are political reasons to cool expectations of energy generation.)

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Update

The New York Times article explains why the new process is unlikely to generate energy:

...because only one in a million of the collisions actually produce fusion, the device is an inefficient generator of energy.

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Michelle Thaller, "Coming in out of the cold: Cold fusion, for real," Christian Science Monitor (June 06, 2005).

Brian Naranjo, James K. Gimzewski and Seth Putterman, "Observation of nuclear fusion driven by a pyroelectric crystal," Nature 434:7037 (28 April 2005), 1115-1118. [Abstract]

Mark Peplow, "Physicists look to crystal device for future of fusion: Desktop apparatus yields stream of neutrons," Nature 434:7037 (28 April 2005), 1057.

Kenneth Chang, "Itty-Bitty and Shrinking, Fusion Device Has Big Ideas," New York Times (April 28, 2005), A18.