Desperately Seeking Fusion in Laboratories
BOSTON — A MONTH and a half after the original report of its ``discovery,'' the outlook is unfavorable for fusion. Many experiments have been run in laboratories around the world seeking to confirm that hydrogen fusion - the power source of the stars - can be made to run at room temperature in a small jar to produce useful amounts of energy.
None of the experimenters has fully confirmed this phenomenon, although a few have reported some signs of fusion or of a net energy output. A number of experimenters, however, have failed to find the phenomenon at all.
The spotlight again returned to the original claimants - B. Stanley Pons of the University of Utah and Martin Fleischmann of the University of Southampton (England). They presented the results of further research to bolster their case Monday night at a meeting of the Electrochemical Society in Los Angeles.
During the meeting they claimed that their latest experiments generated even more excess heat than previous ones.
Drs. Pons and Fleischmann have been experimenting with battery-powered electrolytic cells.
In these cells, two electrodes - one of which is palladium - are immersed in water that has deuterium (doubly heavy hydrogen) in its molecules. The palladium absorbs the deuterium. Then, the Utah researchers claim, deuterium fusion takes place.
Since their March 23 press conference, they haven't released enough details of their work for other scientists to know exactly what they have done. This has left that work open to charges of substantial experimenter error. It also leaves the pair's critics vulnerable to charges that they didn't conduct their experiments properly: During Monday's meeting, Pons said that researchers are not duplicating the Utah results because their palladium electrodes are too small.
Some of the most careful attempts to confirm the Utah claims have been made at the California Institute of Technology and the Massachusetts Institute of Technology. Members of these research teams told an American Physical Society meeting last week that they could find no sign either of fusion or of a net energy output from their electrolytic cells.
They raise several questions. Did Pons and Fleischmann measure energy output correctly? Did they ensure the heat was evenly distributed or did they just detect a local ``hot spot'' near the palladium electrode? Did they measure the voltage difference between the electrodes accurately? A difference of a few tenths of a volt could make the difference between net energy gain and energy loss in the Utah experimenters' calculations. Did they really detect fusion neutrons or were the neutrons from other processes, such as the action of cosmic rays whose effect is as large as that expected from the claimed fusion reactions? This means researchers are looking for a very slight excess of neutrons that might be because of fusion. Even then, experimenters have to make sure they actually count neutrons. Pons and Fleischmann observed gamma rays, which they think were due to neutrons. Skeptics dispute that. Fleischmann said Monday night that he and Pons were working to get better measurements on this aspect of their experiment.
So far, there have been no answers to such questions.
Not even a rival research team led by Steven E. Jones of Brigham Young University in Utah believes in cold fusion as an energy source. It published a detailed paper in the April 27 issue of Nature explaining that team members believe they have detected fusion in electrolytic cells but with energy releases billions of times less than the Utah workers claim. Dr. Jones later said he expects this kind of fusion, even if it is real, will not be a practical source of energy.