Scientists at the University of California at Los Angeles have built a desktop-size fusion device, according to a report published Wednesday.
If the claim seems familiar, it's because 16 years ago, the University of Utah announced that two of its chemists, B. Stanley Pons and Martin Fleischmann, had achieved the impossible: cold fusion. Their small apparatus would provide cheap, clean energy for the world, the U. asserted.
The Utah Legislature quickly appropriated $5 million to pursue patents. Today, long after the project's end, nearly the entire scientific establishment has concluded that the U. project was a pipe dream. The supposed excess energy was never reproduced.
The UCLA device does not pretend to release excess energy that could be used to generate power. But it does use fusion to produce a flux of subatomic particles called neutrons, potentially of real value to medicine and other disciplines.
A difference between the U. device and the one built at UCLA is that the description of the new discovery was accepted and the report was printed in a major peer-reviewed publication, Nature. Based in England, Nature is acknowledged as one of the top scientific journals in the world.
Seth Putterman, physics professor at UCLA and the project's principal investigator, told the Deseret Morning News another way his apparatus is different: "We've shown that what's happening is actually consistent with the laws of physics."
The Nature report is titled "Observation of nuclear fusion driven by a pyroelectric crystal." The co-principal investigator is professor Jim Gimzewski of the chemistry department, and the other author is graduate student Brian Naranjo, both at UCLA. The report is Naranjo's Ph.D. thesis, Putterman said.
A pyroelectric crystal is a mineral that produces electricity as a result of temperature changes. In the experiment, a lithium tantalate crystal was placed in a vacuum chamber covered by lead shielding. The device was cooled by liquid nitrogen.
A heater was turned on, warming the crystal. The temperature change caused an electrostatic field to form. The crystal fired off a beam made up of the nuclei of deuterium atoms. This ion beam was aimed by a tiny tungsten wire attached to the crystal.
The beam smashed into a target with such force that it caused fusion. The fused material released a flux of subatomic particles called neutrons, which were detected by lab equipment.
One hundred seconds after the experiment began, the crystal was producing X-rays. At 160 seconds, neutrons were present at a level higher than the background occurrence. Eventually, "a neutron flux over 400 times background level" was measured, according to the Nature article. The heater was switched off at 170 seconds and the output dropped.
At 393 seconds "the crystal spontaneously discharged by sparking, halting the effect," says the article.
On the surface level, Putterman said in a telephone interview, some people might think that "what we've done looks like it has similarities with cold fusion."
The UCLA device uses a crystal of lithium tentalate. Pons and Fleischmann used palladium. The U. stressed the palladium through electrolysis. UCLA stressed their crystal through heating.
"And then, presto, you get fusion, right?" he said. Actually, the similarities don't continue, he said.
"In their experiment, they never found neutrons, which is a telltale sign of fusion. In our experiment, we found the neutrons."
The apparatus can be built as a "very small device," he added. Unlike the gigantic experimental fusion reactions intended to generate electricity, this is a small neutron generator, he said.
"We would like to see the development of a neutron camera," Putterman added. Like Superman, it could peer through the walls of a steel container.
Or an apparatus could search underground for land mines, he believes. "And we'd like to build millimeter-size X-ray devices that could be threaded through a body" for medical purposes.
Asked if tritium, a product of fusion, was observed, he said, "In addition to producing the neutrons, a certain percent of the fusion events should be producing tritium. So in principle if we analyze our system we should find some residual tritium."
This is not the first time anyone has achieved fusion.
"It's important to realize that you can purchase neutron generators from commercial companies." The cost may be around $100,000, he said. They are basically miniature accelerators, about the size of a dentist's X-ray machine and its power supply.
The authors don't believe the apparatus will be useful for generating electricity.
"What we've shown," Putterman said, "is that we can build something that you can hold in your hands that can produce neutrons."
E-mail: bau@desnews.com