Indian scientist claims holy grail of physics

THE TIMES OF INDIA ^ | TUESDAY, MARCH 05, 2002 9:04:47 PM | CHIDANAND RAJGHATTA

[Madiuq]

WASHINGTON: An Indian-American scientist with the IIT imprimatur has, along with several American colleagues, caused a stir in the world scientific community by claiming to have achieved nuclear fusion in a small table top experiment.

If it is proved right and authenticated by peers, such a fusion – the same principle that fuels the sun – could be the source of cheap, clean and limitless energy, and could change the world.

Scientists have worked for decades in this direction and the possibility that a team might have cracked the problem is considered so remote that the announcement, to be reported in the journal Science later this week, has been greeted with scepticism in the academic community.

Leading the research team making a stab at what is considered the holy grail in the world of physics is Rusi Taleyarkhan, a senior scientist at the Oak Ridge National Laboratory in Tennessee and Richard Lahey, a professor of engineering at the Rensselaer Polytechnic Institute in Troy.

Taleyarkhan earned a bachelor's degree in mechanical engineering from the Indian Institute of Technology, Chennai, and came to the United States in 1977, earning a master's degrees in nuclear engineering and business administration and later a doctorate in nuclear engineering, also from Rensselaer. He considers Dr Lahey, who is also close to India and has consulted with the Indian nuclear establishment, his mentor.

Achieving sustainable nuclear fusion would be a scientific milestone, if not manna. Unlike nuclear fission, splits heavy atoms like uranium and releases some of the excess energy stored as mass in the uranium atoms, fusion joins together light atoms, such as hydrogen, in a reaction that creates a third heavier atom and converts some of the original atoms’ mass into energy.

Because fissionable elements are rare, complex and dangerous, often producing radioactive wastes, scientists have long sought to exploit more readily available elements like hydrogen.

In their article, Taleyarkhan and Lahey report that by blasting liquid acetone (which has deuterium, a heavy hydrogen isotope) with ultrasound, they cause bubbles in the acetone to collapse with such ferocity that they briefly reach temperatures of several million degrees like in the sun. This enabled hydrogen atoms to fuse together and release bursts of energy.

The experiment produced only minuscule amounts of energy, but the scientists feel it might be possible to enlarge the process to a commercially-viable scale. The experiment’s entire apparatus is well within the bounds of “table-top physics,” about “the size of three coffee cups stacked one on top of the other,” says Dr Taleyarkhan.

But many experts scoffed at the claim, although it came with some caveats and a cautionary note from Science magazine editors. Some of them questioned the sustainability of the experiment on a larger scale while others said the work could be contaminated or the researchers may have been fooled by false evidence.

Science writers recalled a similar 1989 hoopla over “cold fusion” that roiled the world of physics before being dismissed as dud. But Taleyarekhan and Lahey say the contretemps was very much on their mind and the experiment had been reviewed extensively before reporting it in Science.

“Of course Mother Nature does throw googlies at us, but we believe it can be scaled and are optimistically cautious,” Dr Taleyarkhan told this correspondent in an interview Tuesday from his lab in Oakridge. “Such a process also has applications other than mass energy production, such as food radiation and chemical synthesis.”

The journal Science itself was non-committal. "In this instance, we see no good reason for suppressing the paper, and even less for attempts to discredit in advance. The premature critics of the result, and those who believe in it, would both do well to cool it, and wait for the scientific process to do its work," it said in an editorial comment.

Dr Taleyarkhan’s has impressive scientific pedigree and credentials. He has been the group leader and program manager in the Engineering and Technology Division of Oak Ridge National Laboratory.

One of his more remarkable inventions is a rifle that can be adjusted so its user fires bullets at varying speeds. The US government has shown great interest in the project because such a non-lethal weapon can be used effectively for peace-keeping, riot-control, and school security.

Son of a prominent Parsi clan of Mumbai, Dr Taleyarkhan’s larger family includes luminaries such as the late Bobby Talyarekhan, the famous radio broadcaster, and Homi Taleyarkhan, a former diplomat. He is married to Navaz Rusi and they have three children, Pervin, Manaz and Meher.

[CWRWinger]

Just a hunch, but Taleyarkhan probably got his masters from the University of North Carolina.

[rdww]

Typical Indian -- they're nuts for cricket.

[JasonC]

I have since read the "Science" article in which the data is presented. My basic attitude is the same - interesting, but probably not what they hope it is. I'll go over what they saw and what the alternate explanations are.

They were using high speed neutrons to start the bubbles - 15 MeV. They did not try to detect fusion by energy budgeting, but by tritium build up and slow neutrons, 2.5 MeV, which is about what you would see released by fusion reactions. They reported a 4% increase in the slow neutron emissions, and a large build up in tritium over a time scale of several hours.

The implied fusion reactions, if that is the source of both, are an order of magnitude higher by the tritium measure, which is reasonable when you allow for the difficulty of detecting the fleeting slow neutrons, compared to the lasting tritium which can be measured afterward.

The most intriguing aspect of it, though, was the use of controls and the sensitivity. They found neither marker effect when using acetone with hydrogens as opposed to heavy hydrogen (regardless of temperature), and they also saw neither marker effect when using a room temperature target instead of a 0 C cooled target. They also did not see it without sonic stimulation.

Why does the last bit matter? Two reasons. One, the failure of others to rapidly duplicate it may be due to the sensitivity of the conditions needed to bring about the effect, whatever its cause. Two, on the surface the obvious competing explanation for the origin of the tritium build up should occur in at least one of the control cases.

The alternate explanation (which is not in the article, but clear enough to me) is that their bubble originating neutrons are causing the nuclear reactions indeed taking place in their sample, not fusions of deuterium with deuterium in the target itself. The order of magnitude of the neutrons fired at the target and of the amount of tritium seen afterward is consistent with this explanation.

They don't think that can be the cause for two reasons. One, the controls. If their stimulus neutrons are the cause, why didn't they see the same in e.g. the warmer deuterium trial? Second, some delicate timing analysis, trying to match the order of neutrons detected with the timing of bubble collapse, which they interprete to mean the slow neutrons originate very close to the center-line of the target cylinder near the final stages of bubble collapse.

I don't find the timing analysis very compelling. It is easy to get such things wrong, experimentally - it is a matter of matching events recorded by different detectors, spaced by milliseconds. Also, they have many events going on, on after another, and many bubbles forming and collapsing at once. It is just as likely they have picked out one of the myriad ways of associating neutrons detected with bubble collapses, which they happen to find encouraging.

The controls are more compelling, but an alternative explanation of them is possible. They think the temperature sensitivity reflects dynamics of bubble formation and collapse - longer build times and more violent collapses are associated with the cooler initial temperature. Fine. But the cooler temperature combined with sonic stimulation should also make for more concentrated targets for the fast neutrons.

See, the sound waves should set up pressure density variations throughout the sample. And the colder target has the atoms more closely packed to begin with. The fast neutrons may be more likely to hit something, when moving through a sample with some denser areas, a more regular lattice, or both.

The obvious way to try to eliminate this possibility is to try a test in which the bubble forming stimulus is not fast neutrons, to avoid the ambiguity they create. Instead of trying to disentangle possible causes of tritium formation, design a test in which the same conditions of bubble collapse they postulate as the cause, is the only possible way for tritium to build up in the sample. Until they do that, they will not convince me.

It remains interesting that they saw tritium build up in some cases (temperature and sound stimulation) and not in others still using deuterium in the acetone target. But it doesn't have to be caused by what they hope they've found.