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152) Recent cold fusion claims:
are they valid?

Ludwik Kowalski (6/28/04)
Department of Mathematical Sciences
Montclair State University, Montclair, NJ, 07043

Introduction
Cold fusion (CF), presumably discovered 15 years ago, is any process in which a nuclear reaction is produced without relying on traditional means, such as particle accelerators, neutron sources, cosmic rays, alpha particles or stellar temperatures. In 1989, several months after the discovery was announced (through a press release at the University of Utah) a panel of scientists, appointed by the US Department of Energy (DOE), examined the evidence supporting the CF claims. That evidence was declared insufficient. But, as summarized in1 “there remain unresolved issues which may have interesting implications. The Panel is, therefore, sympathetic toward modest support for carefully focused and cooperative experiments within the present funding system.”

CF became highly controversial and only several hundred researchers continued working on it, world-wide. Most scientists still think that cold fusion is pseudoscience. On that basis editors of many journals refuse to publish papers devoted to CF research. Only a small fraction of scientists is familiar with recent progress in the area. The purpose of this article is to objectively summarize recent findings2 and to supply references with which I am familiar. The article was triggered by the reported initiative of DOE to review3,4 cold fusion research. I will focus on four cold fusion claims which are, in my opinion, the most important. As a nuclear physicist, and a physics teacher, I examined many CF publications and attended one cold fusion conference5.

Claim #1: unexpected emission of nuclear particles
In the early 1980’s Steven Jones, working at the Los Alamos National Laboratory, explored muonic atoms of hydrogen and the unstable molecules they form6. Such molecules are about 200 times smaller than their stable electronic counterparts. According to a well verified theory of the so-called “tunneling effect,” the proximity of hydrogen atoms in muonic molecules increases the probability of nuclear fusion by many orders of magnitude. This is associated with the release of energy, as in stellar interiors and hydrogen bombs. For nearly a decade the work on muonic atoms was supported by the US government as a possible path toward a new source of energy. The grant, however, was not renewed after it became clear that practical applications, if any, would not materialize in the immediate future.

These investigations led to the idea that cold fusion might be occurring at very high pressures inside planets, as described in7,8. The notion that guides Jones, of a large electron screening effect in the D-D fusion reaction for deuterons embedded in metals, has been independently confirmed by other experimental physicists9,14,15. Can screening be responsible for lowering of the D-D coulomb barrier in a metal? Recent observations of rare neutrons and charged particles, reported by Jones10, give credence to such speculations. The rates of observed emission are usually very low but significantly higher than the background; in one experiment the rate of proton emission was 400 times higher than the background.

The particles, identified as 3 MeV protons, were emitted from spots inside thin titanium foils loaded with deuterium. To load hydrogen ions into the foils Jones placed them (for several hours) into a cylinder filled with deuterium gas at elevated temperature (500o C) and pressure (40 psi). Emission of nuclear particles was subsequently recorded with scintillation and silicon detectors in the low-noise environment. An aluminum foil of 19 microns helped to identify charged particles as protons. Coincidences between protons and other charged particles (tentatively assumed to be 3H) were observed with a set of two silicon detectors. It is worth adding that protons and alpha particles have also been reported by A. Lipson11, R. Oriani12 and A. Karabut13. These researchers worked independently of each other; their methods of loading metals with ions, and their methods of particle detection, were very different from those used by Jones.

The process of emission of such particles remains to be interpreted. For the time being Jones favors the model according to which the 2.45 MeV neutrons and the 3.02 MeV protons are accompanied by 0.82 MeV 3He and by 1.01 MeV 3H, respectively, as in well known thermonuclear reactions. The probability of emission of these particles in a metallic environment, however, is much higher than in hot plasma. A recent paper, published by a team of German scientists9, does show that the cross section of the D(d,p)t reaction, at very low energies (down to 5 keV), is about one order of magnitude larger in the deuterated Ta than in a gas target. Similar observations were made earlier in Japan14,15. Very recently, a team of researchers, from Russian Academy of Science16, found a unique way of observing protons (presumably from the same reaction) down to the energy of 0.8 keV. The observed rate of emission, at the lowest energy, turned out to be nine orders of magnitude higher than predicted by an accepted theory. This seems to indicate that the theory which agrees with experimental data above the energy of 10 keV fails to account for what happens to the embedded ions in titanium at much lower energies. But arguments about a model (screening versus other possible explanations) should not be confused with arguments about the validity of experimental data (observing unexpected neutrons protons and tritons).

Claim #2: accumulation of 4He in excess heat experiments
The claim of excess heat was first made in a famous press conference, on March 23, 1989. That event, and its consequences, are described in several books about cold fusion1,17,18,19,20. Two scientists, M. Fleischmann and S. Pons, announced that they had been conducting research on highly unusual electrochemical cells for several years. These cells were said to be outputting more thermal energy than received in the form of electric energy. The authors wrote that chemical contributions to excess heat were found to be insignificant. On that basis they tentatively concluded that the origin of excess heat was nuclear. Rejecting this hypothesis the critics pointed out that rates of nuclear reactions accompanying excess heat, if the origin of that heat were nuclear, would be many orders of magnitude higher than what was observed. Fleischmann’s research, prompted by theoretical considerations21, was purely experimental. The arguments against it, however, were based on the theoretical model of tunneling effect. The critics assumed that nuclear reactions, presumably responsible for excess heat, should be the same as those in hot plasma. Difficulties reproducing the effect also contributed to initial skepticism.

Subsequent work in the area is described in two books22,23 and in many papers, such as24,25. The authors of these references describe experiments in which excess heat was generated. But they do not always provide enough data to rule out the possibility that a large fraction of excess heat can be due to parasitic chemical reactions, or other non-nuclear processes. Furthermore, according to Shanahan26, the excess heat claims are due to calibration errors. It is difficult to accept this accusation because similar results have been reported by a large number of highly qualified scientists in several countries. On the other hand, one should not ignore the possibility of experimental bias, mutual self-deception, or even fraud. The best evidence that the excess heat is nuclear would be to show the commensurate accumulation of byproducts of nuclear reactions, such as 4He. This will be addressed in connection with claim #4 below.

The most recent contribution, in the area of excess heat, belongs to a group of Chinese scientists27. X. Li, a veteran of cold fusion research, did not use electrochemistry to load palladium with deuterium. The excess heat was generated when compressed gas was allowed to diffuse through a thin palladium wall. According to the authors, that heat could not be explained by the well known Joule-Thomson effect or by chemical reactions. They write: “this experiment has been repeated 6 times already in various configurations. The ‘excess power’ density in the Pd disk is more than 100 W per cubic centimeter, which is about the power density in a fuel rod of a thermal neutron fission reactor.” Reproducible results on generation of excess heat, in a glow discharge chamber (another non-electrolytic method of loading metals with D+ ions), were also reported by Russian scientists13.

Generation of excess heat without producing radioactive material would certainly be desirable. But how can nuclear energy be released without commensurate amounts of radioactivity? According to some theoretical considerations27, deuterium ions embedded in crystals might be influenced by a large number of atoms able to supply and to remove energy “in unison”. Theoretical modeling of natural phenomena, however, and attempts to validate these phenomena experimentally, are two different things. Arguments for or against models do not resolve disputes about validity of experimental data.

Claim #3: highly abnormal isotopic ratios
Chemical elements, not initially present, often accumulate in cold fusion setups, as reported in13, 22, 29, 30. Are new chemical elements due to nuclear reactions or are they impurities introduced during various manipulations? The most direct way of answering this question is to subject the residual chemicals to isotopic analysis. Such analysis shows that isotopic compositions of residuals are often very different from those expected from contamination. According to13, for example, nickel found in a palladium cathode (after the cathode was used to generate excess heat) contained less than 1% of 58Ni; the natural abundance of that isotope is nearly 68%. On the other hand, carbon found in the cathode contained 20% of 13C, while the natural abundance of that isotope is about 1%. Similar results were reported by other researchers22,30. Such findings, if confirmed, would indicate that nuclear processes do take place in some CF setups.

Claim #4: nuclear transmutations
Absence of anticipated products (unjustifiably expected to be the same as in well known thermonuclear reactions) was often used as an argument against cold fusion. A thermonuclear fusion of two deuterons (2H + 2H), for example, nearly always results in production of either 3He or 3H (associated with the emission of neutrons and protons, respectively). Absence of commensurate amounts of neutrons and protons, in excess heat experiments, was often compared to fire without any ashes. That is why the claim of nuclear origin of excess heat was not taken seriously when it was first made in 1989. But several years later progressive accumulation of 4He was reported by several investigators31,32. The authors found that helium generated via cold fusion is mainly 4He; the 3H and 3He atoms are produced much less frequently. The situation is dramatically different from what happens in thermonuclear reactions taking place in ionized gasses. In these reactions the probability of the 2D+2D--> 4He (releasing about 24 MeV of energy) is 10-6 while the probabilities of reactions producing 3H and 3He (releasing about 3 MeV of energy) are roughly 0.5 each.

Furthermore, the energy released in cold fusion (24 MeV per dominant cold fusion event) appears in the form of heat and not in the form of gamma rays (as in rare hot fusion events). How can such differences be explained? That is one of the many unanswered theoretical questions. At present, however, the main issue is experimental rather than theoretical. Is the accumulation of 4He, at the rate of about one atom per 24 MeV of excess heat, real or apparent? Skeptics suspect that helium comes from the surrounding air and not from a totally unexpected nuclear reaction. The authors of the above mentioned reports, however, addressed this issue and ruled out the possibility of atmospheric contamination. If confirmed, such findings could become very significant. They would indicate that 4He is the main “ash” of the mysterious CF “burning,” at least in some cases. Those who objected to cold fusion claims in 1989 expected 3H and 3He to be dominant ashes; how would the discovery of cold fusion have been received if information about 4He was available at that time?

As it turned out, 4He, is not always a dominant “ash” accumulating in excess heat experiments. Production of elements heavier that helium, first reported and then withdrawn by Bockris, was later heralded by some investigators13,22,33. Results from a very extensive study are summarized in 34. The most recent report in this disputed area was presented by Iwamura, from Advanced Technology Research Center, Mitsubishi Heavy Industries, Ltd., in Japan. Addressing the 10th international CF conference (August 2003) Iwamura described a fascinating setup35 in which cesium was turned into praseodymium and strontium was turned into molybdenum. The paper describing these experiments36 had already been published in the Japanese Journal of Applied Physics (JJAP). It is highly significant that the isotopic composition of Mo, produced from Sr, is drastically different from that found in nature. This seems to rule out the possibility of contamination (redistribution of impurities). Low energy transmutations in condensed matter, reported by Iwamura, have been repeated by scientists from Osaka University37.

Final Comments
Cold fusion is not taken seriously by most scientists. But, according to my own informal survey, the opinion of many is still based on what was known in 1989 and not on recent findings. I think that the often repeated labels, such as “pseudoscience” and “fiasco of the century” were perhaps justifiable in 1989, when the first DOE review was conducted. But are such labels justifiable today? Most of us are not equipped to answer this question through laboratory investigations. That is why another official evaluation is desirable. Are the credentials of CF scientists doubtful or not? Are their ways of validation consistent with scientific methodologies? Is there any evidence of deliberate deception? Answers to such questions should help us decide what to think about the controversial field, and what to tell students when they ask questions about it.

Cold fusion claims have often been criticized for being in conflict with the existing theory of nuclear phenomena. Reacting to this one can say that in science a theory should guide while experiments should decide. That is a recognized principle of our scientific method in which theories are models of objective reality. Models often lead scientists to discoveries of new facts but a single confirmed fact contradicting a model is a good reason to modify a theory. On the other hand, an established theory, one that is not only logically consistent, but is also supported by a large number of experimental facts, has a special place in the arsenal of scientific tools. Leaning on such theory is like leaning on the experimental facts supporting it. A theory often protects us from drawing wrong conclusions from experimental data. The initial skepticism about cold fusion was mostly based on the accepted theory; it was not based on critical analysis of new data. The cold fusion controversy, no matter how it is resolved, offers us an insight into the delicate interplay between theoretical and experimental investigations.

References:
References:
1. Huizenga, J. Cold Fusion: the Scientific Fiasco of the Century. Oxford University Press, Oxford, 1993.
2. Cold fusion papers are usually published at specialized scientific conferences. Many of them are 
    downloadable from the library at http://www.lenr-canr.org.
3. Daviss, B. "No Cold Shoulder." New Scientist, March 20, 2004, p 6.
4.  Feder, T. “DOE Warms to Cold Fusion,” Physics Today, April 2004, page 27.
5. The Tenth International Conference on Cold Fusion was held in Cambridge, Massachusetts 24 - 29 August 2003. 
     Conference proceedings, can be downloaded from http://www.lenr-canr.org/iccf10/iccf10.htm
6. Jones, S.E. et al., Phys. Rev. Lett, 51, 1757 (1983)
7. Jones, S.E. et al., Phys. Rev. Lett, 56, 588 (1986)
8.  Jones, S.E. et al., “Cold Nuclear Fusion,” Scientific American, July 1987, p 7 
9.  Raiola, F. et al., "Enhanced electron screening in d(d,p)t for deuterated Ta" Eur. Phys. J. A 13, 377-382 (2002).
10. Jones, S.E.  et al.; August 2003. (Papers at the 10th International Cold Fusion Conference, item 2 above).
11. Lipson, A. et al.;  August 2003. (Paper at the 10th International Conference on Cold Fusion (item 2 above).
12.  Oriani, R. et al.; August 2003. (Paper at the 10th International Cold Fusion Conference (item 2 above).
13. Karabut, A.B. et al.;“Nuclear product ratio for glow discharge in deuterium;” Phys. Let. A, 170, p 265, 1992. 
     Recent findings were presented at the 9th International Cold Fusion Conference in China, 2002. (See 2 above.) 
14. Kasagi, J. et al., “Measurements of the D+D Reaction in Ti Metal with Incident Energies between 4.7 
      and 18 keV;” J.Phys.Soc.Jpn. 64, 3716-3722 (1995)
15. Kasagi, J. et al., “Strongly Enhanced DD Fusion Reaction in Metals Observed for keV D+ Bombardment;” 
      J.Phys.Soc.Jpn. 71, 2881-2885 (2002)
16. Lipson, A. et al., “Enhancement of DD-reaction Accompanied by X-ray Generation in a Pulsed Low Voltage 
      High-Current Deuterium Glow Discharge with a Ti-Cathode.” (Available over the Internet; see item 2 above).
17.  Peat, F.D. Cold Fusion, Contemporary Books, Chicago, 1989.
18. Close, F. Too Hot to Handle: the Race for Cold Fusion, Princeton University Press, New Jersey, 1991.
19.  Mallove, E.F. Fire from Ice: Searching for Truth Behind the Cold Fusion Furror, John Wiley & Sons, Inc., 
       New York, 1991.
20.  Taubes, G. Bad Science: the Short Life and Weird Times of Cold Fusion, Random House, New York, 1993.
21. Fleischmann, M. “Reflections on the Sociology of Science and Social Responsibility in Science, in 
      Relationship to Cold Fusion;” Accountability in Research, 2000. 8: p. 19.
22.  Mizuno, T. Nuclear Transmutations: The Reality of Cold Fusion, Oak Grow Press, Concord, NH, 1998.
23.  Beaudette, C. Excess Heat. Why Cold Fusion Research Prevailed.  Concord, NH, 2000.
24. McKubre, M. at the 10th International Cold Fusion Conference, (Paper available over the Internet; see 2 above).
25. Storms, E. "Excess Power Production from Platinum Cathodes Using the Pons-Fleischmann Effect," in 8th 
      International Conference on Cold Fusion. 2000 Lerici, Italy. (Available over the Internet; see item 2 above). 
26. Shanahan, K. “A systematic error in mass flow calorimetry demonstrated,” Thermochimica Acta 387 (2002) 
      pages 95–100. This article is available over the Internet (see ref. 2 above).
27.  Li, X.Z. et al., “Correlation between abnormal deuterium flux and heat flow in a D/Pd system, ” J.Phys, D: 
        Appl.Phys.36 (2003) 3095-3097. This article is available over the Internet (see item 2 above)
28. Chubb, T., Chubb, S. and Hagelstein, P. presented theoretical papers at the March 2004 meeting of American 
      Physical Society. Their earlier papers are downloadable from the library at 
29. Bockris, J.  “Early Contributions From Workers at Texas A&M University to (So-Called) Low Energy Nuclear 
      Reactions.” Journal of New Energy, 4, no 2, 1999, p. 40.
30.  Miley, G. et al., 2000. "Advances in Thin-Film Electrode Experiments;" 8th International Conference on Cold 
       Fusion Lerici, Italy. This paper is downloadable from the library at 
31. Miles, M. and B.F. Bush, "Heat and Helium Measurements in Deuterated Palladium." Trans. Fusion Technol., 
      26(4T), p. 156., 1994.
32. Arata, Y. and Zhang, Y, "Helium (4He, 3He) within deuterated Pd-black." Proc. Japan Acad. B, 73, p. 1, 1997. 
33. Ohmori, T. et al., “Iron Formation in Gold and Palladium Cathodes,” J. New Energy, 1, no 1, 1996, pp 15-22.
34.  Miley, G. et al., 2000. "Advances in Thin-Film Electrode Experiments;" 8th International Conference on Cold 
       Fusion, Lerici, Italy. This paper is downloadable from the library at 
35. Iwamura, Y. et al. “Energy Nuclear Transmutation In Condensed Matter Induced By 2D Gas Permeation Through 
      Pd Complexes: Correlation Between Deuterium Flux And Nuclear Products” (Paper is available over the 
     Internet (see item 2 above).
36. Iwamura, Y. et al. “Elemental Analysis of Pd Complexes: Effects of 2D gas permeation. Jpn. J. Appl. 
      Phys. 41 (2002), pp. 4642-4648.
37. Higashiyama, T. et al. “Low Energy Nuclear Transmutation In Condensed Matter Induced By 2D Gas 
      Permeation Through Pd Complexes: Correlation Between Deuterium Flux And Nuclear Products.” (This 
      paper is available over the Internet; see item 2 above).

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