Bubble-fusion group suffer setback

news@nature.com ^ | 10 May 2006 | Eugenie Samuel Reich

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Published online: 10 May 2006; | doi:10.1038/news060508-8

Bubble-fusion group suffer setback

Team admits a mix-up with one of their neutron detectors.

Eugenie Samuel Reich

Rusi Taleyarkhan with his table-top fusion equipment in a lab at Oak Ridge, Tennessee, where he conducted research before coming to Purdue.Credit: U.S. Department of Energy file photo/Lynn Freeny

A group of researchers making high-profile claims about fusion energy has admitted to accidentally using equipment different from that reported in their most recent paper.

An erratum providing details of the mistake by Rusi Taleyarkhan of Purdue University and colleagues has been published in Physical Review Letters¹. Critics interpret the admission as a sign that the group's fusion claims² are unravelling, because it comes in the wake of serious questions about the original work's validity (see 'Is bubble fusion simply hot air?').

"Confusing detectors in a discovery of this magnitude is an embarrassing mistake," says Seth Putterman of the University of California, Los Angeles. But Taleyarkhan and colleagues say that their data, analysis and conclusions are not affected by the error.

In January, Taleyarkhan published the most recent of a series of papers in respected journals that claimed to see neutrons characteristic of fusion reactions coming from collapsing bubbles in organic fluids.

If validated, such work could pave the way for cheap, green energy. Taleyarkhan claimed to have deployed three independent methods of detecting these neutrons, one of which was a boron trifluoride gas proportional tube with a polyethylene covering. His erratum notes that this actually turned out to be a lithium iodide crystal scintillation detector, also with a polyethylene covering.

According to the erratum, the error was discovered "upon disassembly of the outer coverings" of the detector and is due to "an oversight which was based on incorrect information from a person's recollection who loaned this apparatus for the study".

Knowing what you're working with

The mistake does not in itself invalidate the experiment's conclusions, but experts say it casts further doubt over the results. Neutron expert Mike Saltmarsh of Oak Ridge National Laboratory in Tennessee, where Taleyarkhan previously worked, points out that doing a good technical job involves knowing what detector is in use.

"If you don't know what you're working with, you can easily make mistakes," says Saltmarsh.

Manuals provided by Ludlum Measurements, which manufactures both types of detector, confirm that different operating voltages and different calibration checks are recommended for the two, for example.

Source of confusion

Brian Naranjo of the University of California, Los Angeles, claimed in March that Taleyarkhan's observed neutrons probably came from a standard lab source rather than fusion reactions³. Naranjo based his study on results from a different detector in Taleyarkhan's setup.

Saltmarsh points out that the data from the lithium iodide detector, as it is now known to be, are consistent with Naranjo's claim. In Taleyarkhan's experiment, the 'boron trifluoride' detector observed high levels of gamma rays (-rays) alongside the neutrons, despite the fact that boron trifluoride detectors are not very sensitive to -rays. Taleyarkhan and his colleagues suggest that neutrons from fusion were interacting with the detector's polyethylene coating to produce a slew of rays.

But the lithium iodide detector is more sensitive to -rays, says Saltmarsh, and the lab source posited by Naranjo could easily have provided enough for the levels observed.

Taleyarkhan's co-author Robert Block, of Rensselaer Polytechnic Institute in New York, disagrees. Block says he and Taleyarkhan still think the observed -rays are produced by fusion neutrons colliding in the polyethylene covering, no matter what the detector.

A university review of Taleyarkhan's work is under way and due to finish by 1 June.

Visit our newsblog to read and post comments about this story.

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References

1. Taleyarkhan R. P., et al. Physical Review Letters, 96. 179903 (2006).

2. Taleyarkhan R. P., et al. Physical Review Letters, 96. 034301 (2006).

3. http://xxx.lanl.gov/abs/physics/0603060

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[.cnI redruM]

This reminds me eerily of what happen at Utah University

[AntiGuv]

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[mikeus_maximus]

Team admits a mix-up with one of their neutron detectors.

I know how they feel. I hate when I do that.

[ClearCase_guy]

"If you don't know what you're working with, you can easily make mistakes," says Saltmarsh.

Insightful.

I think there's an old joke about a guy who invented a Perpetual Motion machine. He takes it to patent office, but they're very reluctant. "We don't accept those, sir. They don't work." But the man says his works. "My machine is different," he says. "All I need is an outlet where I can plug it in and you'll be able to see for yourself."

[pabianice]

Well, on the plus side, there is no longer any danger of a warp core breach...

[marc costanzo]

For a moment I thought this article was about the effect of 'SONOLUMINESCENSE' -

Ultrasonic waves in water or some other suitable liquid, when subjected to standing waves, create a tiny momentary bubble that as it collapses, its' insides will heat up to hotter than the the surface of the Sun for a mircosecond,
thus generating a glow about the bubble's inner surface !

BLAH Blah blah

[EEDUDE]

Don't tell me! Let me guess!

They blew themselves up in a blinding thermonuclear flash!

[Tallguy]

I thought the glow came from plankton...

[Red Badger]

When experimenting with possible nuclear fusion, it's best to know what equipment you're using...............doh!............

[norwaypinesavage]

The words: "high-profile claims" "admitted to" "claims are unraveling" "serious questions about validity" "Is bubble fusion simply hot air"

all occur in the first three sentences of the article. These are prejudicial phrases that would not be typically seen in a fair and balanced news article. Therefore, I am more skeptical of this story than I am of the original cold fusion article.

[dljordan]

"This reminds me eerily of what happen at Utah University"

I was just thinking that. Supposedly reputable scientists say "hey, we found something" then a while later it's "hey, our equipment was bad" or "hey, we made a mistake". You'd think they would be really careful about any announcements from previous experience.

[robertpaulsen]

Maybe these guys can help.

U. chemists B. Stanley Pons, left, and Martin Fleischmann describe their
cold-fusion experiments during a press conference in 1989

[Dark Skies]

You'd think they would be really careful about any announcements from previous experience.

But considering the nature of their work, I wouldn't be too surprised if they were running on adrenaline...and that multiplies the chance of error considerably (been in that position myself).

[jpl]

When experimenting with possible nuclear fusion, it's best to know what equipment you're using...............doh!............

Absolutely. If you aren't careful, you can end up like Doc Ock in "Spider Man 2".

[theFIRMbss]

I swear, Flash and Dale would be goners if Zarkov made these kinds of slips . . .

[Flightdeck]

yeah, it's not cold fusion, though.

[Ole Okie]

I know how they feel. I hate when I do that.

Sorta like landing your plane with your gear up, isn't it? You tend to have that helpless feeling. :^)

[norwaypinesavage]

"yeah, it's not cold fusion, though."

Sonofusion is cold, in the sense that the bulk temperature is "cold". I agree that theoretical temperatures in the cavitation bubbles might be very hot.

[Flightdeck]

Fine, but that's not what separates "cold fusion" from mainstream science, where fusion only occurs (however localized) at extremely high energies.