Condensed matter nuclear science

This article focuses on the physics of low energy nuclear reactions. Please visit cold fusion 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 Template:Ref harvard  :

• electrolysis of heavy water using a palladium, platinum, titanium or nickel cathode, as originally used by Martin Fleischmann and Stanley Pons
• gas discharge (low energy ions) using Pd electrodes in D₂ (H₂) (see mizuno experiment)
• electrolysis of KCl-LiCl-LiD (fused salt) electrolyte using a Pd anode;
• electrolysis of various solid compounds in D₂ (Proton conduction)
• gas reaction (H₂) with Ni under special conditions
• ion bombardment (high energy ions) of various metals by D+;
• cavitation reaction involving D₂O and various metals using an acoustic field
• reaction of finely divided palladium with pressurized deuterium gas
• plasma discharge under D₂O or H₂O
• phase change or chemical reactions
• biological systems, performing biological transmutations as initially reported by Corentin Louis Kervran

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. Template:Ref harvard. In a recent review of research, a large proportion of the panelists were not convinced though.

File:SzpakIRcameraviews.jpg

A infrared picture from a video clip showing the hot spots on the cathode. Presented by Frank Gordon at ICCF10 [11][12][13]

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 Template:Ref harvard. 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 parabolically 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. Template:Ref harvard

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 -> ⁴He. Therefore, cold fusion researchers believe that Helium is partially retained in the cathode.Template:Ref harvard. In a recent review of research, 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 Template:Ref harvard:

• cracks in the palladium cathode, which can form when high deuterium loading is obtained
• minor impurities such as light water or dissolved metal in the electrolyte

Several techniques are reported to improve reproducibility :

• 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 transmutation products. Work in Japan has revealed an entirely new area of research by showing that impurity elements in palladium, through which D₂ 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. . Tadahiko Mizuno, George Miley, 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.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.

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 cesium 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 X-ray photoelectron spectroscopy 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 praseodymium and the strontium was converted to molybdenum. 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. The Iwamura experiment was replicated by experimenters from Osaka University.In later similar experiments by Iwamura Barium 138 was transmuted to Samarium 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.

Proposed mechanisms

Theoretical research in low energy nuclear reactions attempt to answer the following questions:

• how can the coulomb barrier be overcome at low temperatures ?
• how can ⁴He be produced in quantities, when it has a low probability in classic nuclear fusion? What can change these probabilities ?
• how is the energy converted to heat, when gamma rays or other particles are expected?

Here are some proposed mechanisms:

• Bose-Einstein condensate-like: Theoretical work suggests that deuterons in shallow potential wells such as may be found in a palladium metal lattice may exhibit a cooperative behaviour similar to a Bose–Einstein condensate . 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).

• Mössbauer effect-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 . It is interesting to compare this to the Mössbauer effect, 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 -> ⁸Be -> 2 ⁴He Template:Ref harvard.

• Enhanced cross section; neutron formation; particle-wave transformation; resonance, tunneling and screening; exotic particles; formation of proton or deuteron clusters; formation of electron clusters. Template:Ref harvard

• 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 solitons. (See also Zhang, W.-S. et al., 1999, 2000, and 2004.)

• Mitchell Swartz and others have theorized that the lower angular momentum of less energetic, cooler deuterons might affect the initial conditions required and the branching ratios of fusion reactions.[14]

• 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 beta decay.

See also

• Fusor
• Polywell
• Philo T. Farnsworth

• 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 EPRI)
• Naval Research Laboratory
• China Lake Naval Weapons Laboratory(?)
• Mitsubishi
• Centro Ricerche di Frascati, ENEA

• Bhabha Atomic Research Centre (BARC) - active until ??
• Technova - active until ??
• Eastern New Mexico University - Dennis Cravens, a professor of chemistry and physics, is working on a completely self-contained cold fusion device based on a Stirling engine.

References

• ^ Storms, E., Cold Fusion: An Objective Assessment. 2001. [15]
• ^ Hagelstein P. et al., "New physical effects in metal deuterides", submitted to the 2004 DOE panel

Main Papers

• McKubre, M.C.H. et al. (1994) "Isothermal Flow Calorimetric Investigations of the D/Pd and H/Pd Systems." J. Electroanal. Chem., 368, 55.
• Szpak, S. et al. (1995) "Cyclic voltammetry of Pd + D codeposition." J. Electroanal. Chem., 380, 1.
• Celani, F. et al. (1996) "Reproducible D/Pd ratio > 1 and excess heat correlation by 1-microsec-pulse, high-current electrolysis." Fusion Technol., 29, 398.
• Storms, E. (1996) "How to produce the Pons-Fleischmann effect." Fusion Technol., 29, 261.
• Yuki, H. et al. (1997) "D + D reaction in metal at bombarding energies below 5 keV." J. Phys. G: Nucl. Part. Phys., 23, 1459
• Aoki, T. et al. (1998) "Search for nuclear products of the D + D nuclear fusion." Int. J. Soc. Mat. Eng. Resources, 6, 22.
• Szpak, S. et al., (1998) "On the behavior of the Pd/D system: Evidence for tritium production." Fusion Technol., 33, 38.
• Gozzi, D. et al., (1998) "X-ray, heat excess and 4He in the D/Pd system." J. Electroanal. Chem., 452, 251.
• Zhang, W.-S. et al., (1999) "Numerical simulation of hydrogen (deuterium) absorption into β-phase hydride (deuteride) palladium electrodes under galvanostatic conditions." J. Electroanal. Chem., 474.
• Zhang, W.-S. et al. (2000) "Effects of self-induced stress on the steady concentration distribution of hydrogen in fcc metallic membranes during hydrogen diffusion." Phys. Rev. B: Mater. Phys., 62, 8884.
• Cisbani, E. et al., (2001) "Neutron Detector for CF Experiments." Nucl. Instrum. Methods Phys. Res. A, 459, 247.
• Zhang, W.-S. et al. (2002) "Some problems on the resistance method in the in situ measurement of hydrogen content in palladium electrode." J. Electroanal. Chem., 528, 1.
• Li, X.Z. et al. (2003) "Correlation between abnormal deuterium flux and heat flow in a D/Pd system." J. Phys. D: Appl. Phys., 36, 3095.
• Zhang, W.-S. et al., (2004) "Effects of reaction heat and self-stress on the transport of hydrogen through metallic tubes under conditions far from equilibrium." Acta Mater., 52, 5805.
• Szpak, S. et al. (2004) "Thermal behavior of polarized Pd/D electrodes prepared by co-deposition. Thermochim. Acta, 410, 101.
• Szpak, S. et al. (2005) "The effect of an external electric field on surface morphology of co-deposited Pd/D films." J. Electroanal. Chem., 580, 284.
• Szpak, S. et al. (2005) "Evidence of nuclear reactions in the Pd lattice." Naturwiss., 92, 394.
• Storms, E. (2006) "Comment on papers by K. Shanahan that propose to explain anomalous heat generated by cold fusion." Thermochim. Acta, 441, 207.