Sun in a Bottle (20 page)

Jones, Pons, and Fleischmann had entered an ever-quickening race to run experiments, prove the existence of cold fusion, write a paper for a peer-reviewed journal, and publish it. By early 1989, the competitors had agreed to submit simultaneous papers to
Nature
, so they could all cross the finish line simultaneously. But in a climate of increasing mistrust and antagonism, Pons and Fleischmann jumped the gun. They submitted their paper to the
Journal of Electroanalytical Chemistry
on March 10, and within two weeks they were in front of the microphones, touting their achievement to the world—despite the improbability of what they had found. “Stan and I often talk of doing impossible experiments,” Fleischmann said in the official University of Utah press release about cold fusion. “We each have a good track record of getting them to work.”

 

 

In truth, Pons and Fleischmann did not have the grounds for such hubris. Though they exuded confidence at the March 23 press conference, they already should have known that their data did not add up. They had several lines of evidence for the claim that they had achieved nuclear fusion in their tiny little beakers—but these lines contradicted one another.

The strongest line of evidence, as far as the chemists were concerned, was heat. When Pons and Fleischmann measured the temperature of their apparatus, their electrochemical “cell,” they discovered that the palladium was warming it up ever so slightly. Of course, many things can warm up a cell—the electricity they were running through the cell, for example, was certainly contributing to the warming—but Pons and Fleischmann argued that the energy coming from the palladium was considerably more than what they added in the form of electricity. According to Pons, an inch-long and quarter-inch-thick palladium wire brought water to a boil within minutes, and for every watt of power the scientists put in, four watts came out. More energy out than in implies a reaction of some sort. Since the reaction kept going and going, reportedly for more than one hundred hours, the amount of energy coming from the cell was too large to be explained by a chemical reaction. It was like Marie Curie’s hunk of radium; mere chemical processes couldn’t seem to explain the heat coming from the cell. To Pons and Fleischmann, this was a smoking gun of a nuclear reaction: fusion.

This sort of evidence would not convince most physicists. To them, the only way to prove that you have achieved fusion is, naturally enough, to show that you are producing some of the by-products of fusion. With deuterium-deuterium fusion, there are a few unambiguous signals that a reaction has taken place.

When two deuterium nuclei fuse (d + d), they stick together for a tiny fraction of a second: two protons and two neutrons in a quivering, energetic bundle. Because the conglomerate is so energetic, it cannot hold together completely. One particle is going to pop off and carry away some excess energy. That means either a proton (p) is going to pop off, leaving behind a tritium particle (t) with one proton and two neutrons,

 

or a neutron (n) is going to pop off, leaving behind a helium-3 nucleus with two protons and one neutron,

 

These two branches of the reaction are roughly equally likely: half of the time that you fuse two deuterium nuclei, you will get a proton and a tritium nucleus; the other half, a neutron and a helium-3 nucleus.

Free-floating protons are relatively common, but free-floating neutrons are rarer, as are tritium and helium-3. So if you think that you’ve got deuterium-deuterium fusion going on in your laboratory, the best way to convince other people is to demonstrate that you are making tritium, helium-3, and neutrons. The neutrons, arguably, should be the easiest to detect. Neutrons penetrate matter very easily, so any neutrons produced by the reaction would quickly fly out through the walls of the beaker and into the walls surrounding the room. A neutron detector need only be placed next to the reactor vessel and it would certainly pick up some of these particles. There are neutrons from other sources—cosmic rays, for example, often produce them in the lab—but luckily the neutrons from deuterium-deuterium fusion have a specific energy.

The fusion of two deuterium nuclei produces a fixed amount of energy: the energy that the particles get from rolling one step down the fusion hill toward the valley of iron. That energy is carried away by the particles created by the reaction. For the branch of the reaction that creates a neutron and a helium-3, the total energy released—in the units that nuclear physicists like to use—is nearly 3.3 million electron volts (3.3 MeV).
⁵⁵
That energy is split between the two particles. Furthermore, the heavier particle gets less energy, while the lighter particle gets more.
⁵⁶
In this particular case, the heavier helium-3 gets about 0.82 MeV while the lighter neutron gets 2.45 MeV. Every time. So, if you find neutrons flying about with 2.45 MeV of energy, it is a really good sign that you are seeing deuterium-deuterium fusion.

Before the press conference, Pons, Fleischmann, and Jones had all been looking for neutrons. Jones’s team thought it had found a few coming from their experiments—a small, unimpressive bump in a graph. The bump didn’t represent a solid discovery; after months of running the experiment, Jones claimed to see roughly twenty neutrons in the 2.45 MeV range. Unimpressive, yes, but Jones considered them a solid sign of fusion reactions. That these neutrons were there at all “provides strong evidence that room-temperature nuclear fusion is occurring at a low rate” in the experiment, Jones later wrote. Pons and Fleischmann had been looking, too, but they were having even less luck. Fleischmann used his Harwell laboratory connections to get a neutron detector, but when they put it near the cell, it didn’t show any neutrons. This was a huge problem, because for every watt of power the cell produced, about a trillion neutrons should have been flying out every second. At the power levels Pons and Fleischmann were seeing, their beaker should have been emitting dangerous and easily detectable levels of radioactivity. But it wasn’t.

As the days of fruitless searching turned into weeks and the time of the press conference drew closer, Pons and Fleischmann evidently became increasingly concerned. They sent a cell to Harwell to be analyzed with a much more sensitive machine, but the analysis required some time. In the interim, they invited a person from the University of Utah’s radiation safety office to the lab to measure gamma rays coming from the cell. The gamma rays, they hoped, would provide an indirect measure of neutrons: when a 2.45 MeV neutron strikes a hydrogen in the water surrounding the palladium, it will emit a gamma ray, again with a very specific energy: 2.22 MeV. The safety officer set up a gamma-ray detector for a few days and collected data. Apparently, Pons and Fleischmann were thrilled with what the machine found, because shortly after analyzing the data, they submitted their paper to the
Journal of Electroanalytical Chemistry
and Utah began setting up the press conference.

 

 

When Pons and Fleischmann announced their discovery to the world on March 23, 1989, Utahans immediately sought to capitalize on the news. The day after the press conference, Governor Norman Bangerter announced that he would call a special session of the legislature to appropriate $5 million for cold-fusion research. The appropriations bill passed overwhelmingly. The money would help establish a National Institute for Cold Fusion at Utah. Soon cold-fusion lobbyists would be marching up Capitol Hill seeking tens of millions of dollars, promising that Japan would steal cold-fusion momentum away from the United States if the nation didn’t invest immediately.

The scientific community was of two minds. Some were optimistic. Edward Teller called to congratulate Pons and Fleischmann and started a Livermore task force to look into cold fusion. Others, including the University of Utah’s own physics department, which had been kept in the dark by the chemists, were extremely wary of the results. No matter the level of skepticism, every scientist wanted details about the experiments, and there were few to be had.

Pons and Fleischmann had held their press conference before publishing their data and their methods. This was very unusual. Scientists communicate through scientific presentations and papers, not through press releases and press conferences. On the relatively rare occasions that a scientific result is important enough to merit a press event, it is usually held at the same moment that the data are revealed to the scientific community through a paper or in a presentation. With the cold-fusion announcement, the paper was missing. No data were available, and scientists had only the scantest details about how Pons and Fleischmann performed their experiment.

Physicists and chemists around the world were frantic; without any data, they had little way to judge whether Pons and Fleischmann were going to solve the world’s energy crisis—or whether they were merely full of it. The suspense would last for months.

In the first few days after the press conference, the news seemed good for the two chemists. The press soon learned about Jones’s work, and while Jones was much less bold in claiming to generate energy, he, too, was claiming to see fusion in palladium. It appeared to be an outside confirmation of the Pons and Fleischmann claim. No longer could cold fusion be considered the delusion of a single laboratory. As other labs rushed to replicate the experiments, news began to filter in about other confirmations. By early April, researchers at Texas A&M were seeing excess heat in palladium cells; Georgia Tech was seeing neutrons. The University of Washington was seeing tritium. These reports all seemed to provide solid support for cold fusion.

Privately, though, Pons and Fleischmann were getting bad news. Two days before the press conference, Fleischmann learned that even the hypersensitive neutron detector at Harwell wasn’t picking up anything. There was no trace of the trillions and trillions of neutrons that should have been flowing from the palladium. Fleischmann apparently explained the discrepancy away, noting that a number of cells that he and Pons had built didn’t work; perhaps Harwell was using a defunct cell. It was not a convincing explanation, but it would have to do. But worse news was to come, news that was harder to dismiss.

Four days after the press conference, Pons and Fleischmann began to reveal details of the experiments to some of their colleagues. Fleischmann visited the Harwell lab and gave a seminar on cold fusion. The room was packed with scientists, including some very esteemed ones who had been working with neutrons and gamma rays for years. When Fleischmann showed his gamma-ray measurements to the Harwell crowd, they were shocked. A typical gamma-ray spectrum is a bumpy graph that shows a series of peaks and troughs at various energies, reflecting natural background sources of gamma radiation (such as the decay of radioactive elements). Gamma rays from deuterium should have occurred at 2.22 MeV, right between a gentle peak caused by the decay of radioactive bismuth at 2.20 MeV and a much larger one caused by the decay of radioactive thallium at 2.61 MeV. Instead, Fleischmann showed a ratty little plot that displayed only a single peak, without any nearby landmarks to confirm what the peak really was. Worse yet, Fleischmann was claiming that he was seeing gamma rays that had 2.5 MeV of energy, not the 2.22 MeV that a fusion neutron should emit when it strikes a tub of water.
⁵⁷
The peak was in entirely the wrong place. The director of Harwell turned to Fleischmann and said, simply, “It’s wrong.” Fleischmann wilted. The next day, physicists at the University of Utah—who had been given a preprint of the upcoming cold-fusion paper—told Pons precisely the same thing.

What was going on? Why was the gamma-ray peak in the wrong place? To all appearances, Fleischmann and Pons dismissed the problem, attributing it to a minor error in calculation. When their paper finally came out in the
Journal of Electroanalytical Chemistry
, the lone peak was sitting in precisely the right spot: 2.22 MeV. Perhaps they told the editors about the “error” and corrected it before it was published. However, Pons and Fleischmann apparently failed to spot one occurrence of the old, incorrect value of 2.5 MeV in the manuscript: in the equation where they describe the interaction between a neutron and a hydrogen atom, they declare that the gamma ray would be at 2.5 MeV, not the 2.22 MeV shown by the spectrum.

The problem of the moving peak wasn’t public yet, though it soon would be. In the days after the press conference, scientists, still hungry for details about the Pons and Fleischmann experiments, were taking desperate measures. Physicists apparently hacked into Pons’s e-mail account looking for clues. One scientist spooked Utah chemists by loitering outside the Pons-Fleischmann lab. A team of plasma physicists at the Massachusetts Institute of Technology resorted to scouring television footage of the lab instruments for data. They succeeded: a broadcast on Utah’s KSL-TV showed the entire gamma-ray spectrum, clearly showing the bismuth and thallium peaks. Using that information, they deduced that Pons and Fleischmann’s peak had to be near 2.5 MeV as originally presented during the seminar at Harwell, not at 2.22 MeV, as reported in the journal article. Furthermore, even without the television footage, the MIT researchers showed that the Pons-Fleischmann peak was the wrong shape—too narrow and without a distinctive shoulder—for one produced by neutron-created gamma rays. It was a devastating critique, and when Pons and Fleischmann responded to the MIT criticisms in June, the peak had somehow moved back to 2.5 MeV. By that time, most mainstream physicists had already decided that cold fusion was bunk.

However, in late March and early April, the question was still open. While the physicists were still trying to figure out precisely what Pons and Fleischmann had done, the scientific and political communities were dividing into believers and nonbelievers. The biggest critics of cold fusion were plasma physicists. These were the people who knew a lot about the difficulty of achieving fusion, and who had learned through painful experience how neutrons can fool you. They were also the people who had the most to lose if cold fusion worked. Cold-fusion supporters began to sense a conspiracy to attack the Pons-Fleischmann discovery. “There is big money in hot fusion, and if we turn out to be right, hot fusion, I guess, goes away,” said the University of Utah president, Chase Peterson. “That represents entire careers, and orthodontia, and college educations for whole families of people that have lived off that dole.” In the eyes of supporters, the critics of cold fusion, largely on the East and West Coasts, threatened with obsolescence, were striking at the discoverers of cold fusion in Utah, in the heartland. The university’s vice president for research, James Brophy, supported this view: “The black hats, such as they were, came from the hot fusion community.... There was certainly an organized campaign to discredit cold fusion based on the possibility of losing funding.”