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| :''This article focuses on the physics of low energy nuclear reactions. Please visit ] for a history and discussion of the controversy. | |||
| '''Condensed matter nuclear science''' (CMNS) is an area of research that focuses on the various anomalies in metal hydrides and deuterides. It is also sometimes called "Chemically assisted nuclear reaction" or "Low energy nuclear reaction". | |||
| ==Experimental evidence== | |||
| A variety of experimental setup have been used to study low energy nuclear reactions {{ref_harvard|Storms2001|Storms 2001|}} : | |||
| * ] of ] using a ], ], ] or ] ], as originally used by ] and ] | |||
| * gas discharge (low energy ions) using Pd electrodes in D<sub>2</sub> (H<sub>2</sub>) (see ]) | |||
| * electrolysis of KCl-LiCl-LiD (fused salt) electrolyte using a Pd anode; | |||
| * electrolysis of various solid compounds in D<sub>2</sub> (Proton conduction) | |||
| * gas reaction (H<sub>2</sub>) with Ni under special conditions | |||
| * ] bombardment (high energy ions) of various metals by D+; | |||
| * cavitation reaction involving D<sub>2</sub>O and various metals using an acoustic field | |||
| * reaction of finely divided palladium with pressurized deuterium gas | |||
| * plasma discharge under D<sub>2</sub>O or H<sub>2</sub>O | |||
| * phase change or chemical reactions | |||
| * biological systems, performing biological ]s as initially reported by ] | |||
| ===Evidence of excess heat and helium production=== | |||
| Cold fusion researchers say that excess heat has been observed with a variety of calorimeters based on varying operating principles and by different groups in different labs, all largely with similar results. They say that the possibility of calorimetric errors has been carefully considered, studied, tested and ultimately rejected by cold fusion researchers. {{ref_harvard|Hagelstein2004|Hagelstein 2004|}}. In a recent ], a large proportion of the panelists were not convinced though. | |||
| ] picture from a video clip showing the hot spots on the cathode. Presented by Frank Gordon at ICCF10 |220px]] | |||
| Cold fusion researchers say that the excess heat effect has been located on the surface of the metal deuteride cathode, in very small, isolated regions heating up in random fashion {{ref_harvard|Storms2001|Storms 2001|}}. They measured energy density at 450 eV/atom and above, a value much greater than what might be expected from chemical effects. They say that the effect appears to increase approximately ]ally with the level of the D:Pd atomic ratio in the cathode, above a threshold of D:Pd of about 0.875. Below that threshold of loading, they do not observe an effect; above that threshold, they say that about half the cells manifested excess heat well above measurement uncertainty. {{ref_harvard|Hagelstein2004|Hagelstein 2004|}} | |||
| Several studies have reported that the rate of helium production measured in the gas stream varies linearly with excess power. However, the amount of helium in the gas stream appears to be about half of what would be expected for a heat source of the type D + D -> <sup>4</sup>He. Therefore, cold fusion researchers believe that Helium is partially retained in the cathode.{{ref_harvard|Hagelstein2004|Hagelstein 2004|}}. In a recent ], a majority of the panelists were not convinced that there is evidence of nuclear reactions. | |||
| The following elements have been reported to prevent appearance of low energy nuclear reactions {{ref_harvard|Storms2001|Storms 2001|}}: | |||
| * cracks in the palladium cathode, which can form when high deuterium loading is obtained | |||
| * minor impurities such as ] or dissolved metal in the electrolyte | |||
| Several techniques are reported to improve reproducibility {{Fact|date=February 2007}}: | |||
| * cold-working | |||
| * oxidation in air followed by electro-reduction | |||
| * certain additives such as boron in the palladium | |||
| * using electrodeposited cathodes, which have a predictable structure and which can be co-deposited with D to produce an already loaded cathode, eliminating the delay to fusion | |||
| * certain additives such as aluminum ions | |||
| ===Evidence of nuclear transmutation=== | |||
| The presence of heavy elements having unnatural isotopic ratios and in unexpectedly large amounts have been claimed to be detected under some conditions. These are the so called ] products. Work in Japan <ref>Iwamura, Y., et al. Low Energy Nuclear Transmutation In Condensed Matter Induced By D<sub>2</sub> Gas Permeation Through Pd Complexes: Correlation Between Deuterium Flux And Nuclear Products. in Tenth International Conference on Cold Fusion. 2003. Cambridge, MA: LENR-CANR.org. </ref> <ref>Iwamura, Y., et al. Observation of Low Energy Nuclear Reactions Induced By D2 Gas Permeation Through Pd Complexes,. in The 9th International Conference on Cold Fusion, Condensed Matter Nuclear Science. 2002. Beijing, China: Tsinghua Univ. Press. </ref> <ref>Iwamura, Y., M. Sakano, and T. Itoh, Elemental Analysis of Pd Complexes: Effects of D<sub>2</sub> Gas Permeation. Jpn. J. Appl. Phys. A, 2002. 41: p. 4642. </ref> <ref>Iwamura, Y., T. Itoh, and M. Sakano. Nuclear Products and Their Time Dependence Induced by Continuous Diffusion of Deuterium Through Multi-layer Palladium Containing Low Work Function Material. in 8th International Conference on Cold Fusion. 2000. Lerici (La Spezia), Italy: Italian Physical Society, Bologna, Italy. </ref> has revealed an entirely new area of research by showing that impurity elements in palladium, through which D<sub>2</sub> is caused to pass, may be converted to heavier elements. The claims have been replicated in Japan and similar investigations are underway at the U.S. Naval Research Laboratory (NRL). | |||
| Nuclear transmutations have been reported in cold fusion experiments since 1992. .<ref>Karabut, A. B., Y. R. Kucherov, and I. B. Sarratlmova. Possible Nuclear Reactions Mechanisms of Glow Discharge in Deuterium. In Third International Conference on Cold Fusion, “Frontiers of Cold Fusion”. 1992. Nagoya Japan Universal Academy Press, Inc. Tokyo, Japan. [http://lenr-canr.org/acrobat/KarabutABpossiblenu.pdf | |||
| ]</ref> Tadahiko Mizuno, ], and Yasuhiro Iwamura and their associates are prominent transmutation experimenters. Many other experimenters also saw transmutation evidence in their experiments. In Mizuno’s experiments trace amounts of many kinds of elements appeared on palladium cathodes after electrolysis that produced excess heat. In a particular experiment the elements found were C, O, Cl, Si, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Sn, Pt, Hg, Pb, As, Ga, Sb, Te, I, Hf, Re, Ir, Br, Xe. Some of these elements existed as impurities in the cathode (palladium) , anode (platinum), or electrolyte (lithium hydroxide). However some like zinc and xenon did not. Large differences from natural isotopic ratios were seen for Cr, Cu, Zn, Xe, Pd, and Pt. In general it requires gaseous diffusion or a nuclear reaction to change an element from its natural isotope ratio. Thus an unnatural isotope ratio makes contamination an implausible explanation.<ref>Mizuno, T. “Experimental Confirmation of the Nuclear Reaction at Low Energy Caused by Electrolysis in the Electrolyte”. Proceeding for the Symposium on Advanced Research in Technology 2000, Hokkaido University, March 15, 16, 17, 2000. pp. 95-106</ref>Miley wrote a review of many experiments where transmutation occurred. He reported that transmuted element masses were higher than the maximum possible impurity masses in some experiments. Calcium, copper, zinc, and iron were the most common reported elements. Rare earth elements were found which is important because rare earth elements are unlikely to be impurities.<ref>Miley, G. H. and P. Shrestha. Review Of Transmutation Reactions In Solids. in Tenth International Conference on Cold Fusion. 2003. Cambridge, MA.</ref> | |||
| So far the clearest evidence for transmutation has come from Iwamura and associates. An important experiment was published in 2002 in the Japanese Journal of Applied Physics which is one of the top physics journals in Japan. In this experiment a thin film of palladium was deposited on top of alternating thin layers of palladium and calcium oxide on top of bulk palladium to form a gas membrane. In one case a thin layer of ] was deposited on top of the membrane. In another case a thin layer of strontium was deposited on the thin film of palladium. Deuterium gas was on the cesium or strontium side of the membrane and a vacuum chamber was on the bulk palladium side. The gas was allowed to permeate for from 2 days to a week when the deuterium gas chamber was evacuated and ] tests were conducted to measure transmutations. Then the deuterium gas was replaced to continue the test. Thus the rate of transmutation was measured against time. It was found that the cesium was converted to ] and the ] was converted to ]. These transmutations represent an addition of 4 protons and 4 neutrons to the original element. This experiment was conducted in a Mitsubishi Heavy Industries clean room. <ref>Yasuhiro Iwamura, Mitsuru Sakano, and Takehiko Itoh.</ref>The Iwamura experiment was replicated by experimenters from Osaka University.<ref>Taichi Higashiyama, Mitsuru Sakano, Hiroyuki Miyamaru, and Akito Takahashi. “Replication of MHI Transmutation Experiment by D2 Gas Permeation Through Pd Complex”. Tenth International Conference on Cold Fusion. 2003.</ref>In later similar experiments by Iwamura ] 138 was transmuted to ] 150 and Barium 137 was transmuted into Samarium. The Barium 138 experiment used a natural isotope ratio of Barium. The Barium 137 experiment used a Barium 137 enriched isotope ratio. The transmutations represent an addition of 6 protons and 6 neutrons. However attempts at a theory are being made by Takahashi and others.<ref>Takahashi A. “Mechanism of Deuteron Cluster Fusion by EQPET Model”. in Tenth International Conference on Cold Fusion. 2003</ref> | |||
| ==Proposed mechanisms== | |||
| Theoretical research in low energy nuclear reactions attempt to answer the following questions: | |||
| * how can the ] be overcome at low temperatures ? | |||
| * how can <sup>4</sup>He be produced in quantities, when it has a low probability in classic ]? What can change these probabilities ? | |||
| * how is the energy converted to heat, when ]s or other particles are expected? | |||
| Here are some proposed mechanisms: | |||
| * ''']-like''': Theoretical work suggests that ]s in shallow potential wells such as may be found in a palladium metal lattice may exhibit a cooperative behaviour similar to a ] {{Fact|date=February 2007}}. This would allow nuclei to react despite the coulomb barrier, due to tunneling and superposition. However, traditional Bose condensates only occur at much lower temperatures (close to absolute zero). | |||
| <!--"Ion band states", Bloch condensates (source)--> | |||
| * ''']-like''': Theoretical work suggests that the energy of fusion can be transmitted to the entire metal lattice rather than a single atom, preventing the emission of gamma rays {{Fact|date=February 2007}}. It is interesting to compare this to the ], in which the recoil energy of a nuclear transition is absorbed by a crystal lattice as a whole, rather than by a single atom. However, the energy involved must be less than that of a phonon, on the order of ?? keV, compared with 23 MeV in nuclear fusion. | |||
| * '''Multi-body interactions''': The following reaction, if proven to exist, would not generate gamma rays: d+d+d+d -> <sup>8</sup>Be -> 2 <sup>4</sup>He {{ref_harvard|Storms2001|Storms 2001|}}. | |||
| * Enhanced cross section; neutron formation; particle-wave transformation; resonance, tunneling and screening; exotic particles; formation of proton or deuteron clusters; formation of electron clusters. {{ref_harvard|Storms2001|Storms 2001|}} | |||
| * Deuterons embedded in palladium could settle at points and in channels within the metal's electron orbitals which substantially increase the likelihood of deuteron collisions. (Jones, S.E., ''et al.'' (1989) "Observation of Cold Nuclear Fusion in Condensed Matter," ''Nature,'' '''338,''' 737-740.) V.A. Filimonov and his colleagues in Russia have described this as a combination of deuteron cluster formation, shock wave fronts involving phase boundaries, and the directional propagation of ]s. (See also Zhang, W.-S. ''et al.,'' 1999, 2000, and 2004.) | |||
| * Mitchell Swartz and others have theorized that the lower ] of less energetic, cooler ] might affect the initial conditions required and the ]s of fusion reactions. | |||
| * In 2005, Alan Widom and Lewis Larsen proposed a theory that could explain the experimental results without D-D fusion nor tunneling through a high Coulomb barrier. Based on mainstream physics, it proposes that electrons and protons react to form low momentum neutrons, that these neutrons are absorbed by surrounding atoms, and that these atoms are transmuted by ]. <ref>Widom, Larsen, "''Ultra Low Momentum Neutron Catalyzed Nuclear Reactions on Metallic Hydride Surfaces.''", <br> cited by New Energy Times, "Newcomers to Condensed Matter Nuclear Science Rock the Boat, Part 2", Nov 10, 2005, </ref> | |||
| == See also == | |||
| *] | |||
| *] | |||
| *] | |||
| * An interesting discussion on the cold fusion theoretical viability can be seen in the Chemistry Forum: | |||
| http://www.chemicalforums.com/index.php?topic=17140.0 | |||
| where the nuclear chemist Mitch wrote in the beginning of the discussion: "In conclusion, giving coverage to this fringe science only helps perpetuate the false belief that there exists any viability in cold fusion". But in the end of the discussion he is not quite sure that cold fusion viability is a false belief, because he wrote: "I have not heard of Zitterbewegung energy before, and have been studying up on it before giving a formal response. Sorry for the delay" | |||
| ==Current research groups== | |||
| * SRI (partly funded by ]) | |||
| * Naval Research Laboratory | |||
| * China Lake Naval Weapons Laboratory(?) | |||
| * Mitsubishi | |||
| * Centro Ricerche di Frascati, ENEA | |||
| * Bhabha Atomic Research Centre (BARC) - active until ?? | |||
| * Technova - active until ?? | |||
| * ] - Dennis Cravens, a professor of chemistry and physics, is working on a completely self-contained cold fusion device based on a ]. | |||
| ==References== | |||
| * {{note|Storms2001}} Storms, E., Cold Fusion: An Objective Assessment. 2001. | |||
| * {{note|Hagelstein2004}} Hagelstein P. et al., "''''", submitted to the ] | |||
| ==Main Papers== | |||
| * McKubre, M.C.H. ''et al.'' (1994) ''J. Electroanal. Chem.,'' '''368,''' 55. | |||
| * Szpak, S. ''et al.'' (1995) ''J. Electroanal. Chem.,'' '''380,''' 1. | |||
| * Celani, F. ''et al.'' (1996) ''Fusion Technol.,'' '''29,''' 398. | |||
| * Storms, E. (1996) ''Fusion Technol.,'' '''29,''' 261. | |||
| * Yuki, H. ''et al.'' (1997) ''J. Phys. G: Nucl. Part. Phys.,'' '''23,''' 1459 | |||
| * Aoki, T. ''et al.'' (1998) ''Int. J. Soc. Mat. Eng. Resources,'' '''6,''' 22. | |||
| * Szpak, S. ''et al.,'' (1998) ''Fusion Technol.,'' '''33,''' 38. | |||
| * Gozzi, D. ''et al.,'' (1998) ''J. Electroanal. Chem.,'' '''452,''' 251. | |||
| * Zhang, W.-S. ''et al.,'' (1999) ''J. Electroanal. Chem.,'' 474. | |||
| * Zhang, W.-S. ''et al.'' (2000) ''Phys. Rev. B: Mater. Phys.,'' '''62,''' 8884. | |||
| * Cisbani, E. ''et al.,'' (2001) ''Nucl. Instrum. Methods Phys. Res. A,'' '''459,''' 247. | |||
| * Zhang, W.-S. ''et al.'' (2002) ''J. Electroanal. Chem.,'' '''528,''' 1. | |||
| * Li, X.Z. ''et al.'' (2003) ''J. Phys. D: Appl. Phys.,'' '''36,''' 3095. | |||
| * Zhang, W.-S. ''et al.,'' (2004) ''Acta Mater.,'' '''52,''' 5805. | |||
| * Szpak, S. ''et al.'' (2004) ''Thermochim. Acta,'' '''410,''' 101. | |||
| * Szpak, S. ''et al.'' (2005) ''J. Electroanal. Chem.,'' '''580,''' 284. | |||
| * Szpak, S. ''et al.'' (2005) ''Naturwiss.,'' '''92,''' 394. | |||
| * Storms, E. (2006) ''Thermochim. Acta,'' '''441,''' 207. | |||
| ==Notes== | |||
| {{reflist}} | |||
| {{fusion power}} | |||
| ] | |||
| ] | |||
| ] | |||
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