Critique: Widom-Larsen Theory

Theoretical Standard Model Rates of Proton to Neutron Conversions Near Metallic Hydride Surfaces

This is a Widom-Larsen paper, published on arXiv in 2006, last version 2007. From comments by Widom and Larsen on New Energy Times, the intention was to submit this to a refereed journal. That apparently never happened.

This is the beginning of a review of that paper.

Excess heats of reaction have often been observed to be generated in the metallic hydride cathodes of certain
electrolytic chemical cells. The conditions required for such observations include high electronic current densities
passing through the cathode surface as well as high packing fractions of hydrogen or deuterium atoms within the metal. Also directly observed in such chemical cells are nuclear transmutations into elements not originally present prior to running a current through and/or prior to applying a LASER light beam incident to the cathode surface[1, 2, 3, 4, 5, 6]. It seems unlikely that the direct cold fusion of two deuterons can be a requirement to explain at least many of such observations[7] because in many of these experiments, deuterons were initially absent. For simplicity of presentation, we consider “light water” chemical cells in which deuterons are not to any appreciable degree present before the occurrence of heat producing nuclear transmutations.

Immediately obvious to me is a degree of misrepresentation of LENR research, as if by a caricature of it. It is true that correlation has been shown between excess heat, and current density (but not what would ordinarily be considered “high”),  and packing fraction (which was, indeed, higher than normally thought attainable); however, these conditions were not sufficient to create the heat effect, and more recent evidence indicates that high current may be correlated to high deuterium flux, as well, which is then correlated with expansion and contraction of the material, causing material changes, and possibly accumulated surface impurities, and it is these material changes, when specific conditions are present, that lead to the heat effect.

Hydrogen generally either produces no effect or the effect is greatly reduced. As well, transmutations are observed, but at very low levels; the predominant ash from the reaction is helium; other transmutations may be a million times or lower in level.

“Direct cold fusion of two deuterons” is a red herring (though it would be common for people first approaching LENR); while some theories do still posit something like that, it is obvious that the reaction, whatever it is, is not ordinary fusion of two deuterons, and most theorists are working with collective or multibody effects in some way (as do Widom and Larsen).

I was moved to look at this carefully by a private discussion of W-L theory as to the “ultralow momentum neutrons,” bringing out certain problems there.

Nuclear transmutations in the work which follows are attributed to the creation and absorption of ultra low momentum neutrons as well as related production of neutrinos.

What is an “ultra low momentum neutron”?

Numerically, for na ∼ 10^22/cm3 neutron absorbers per unit volume with an imaginary part of the scattering length b ∼ 10^−13 cm and with ultra-low momentum neutrons formed with a wavelength of λ ∼ 10^−3 cm, a neutron will move on a length scale of Λ ∼ 10^−6 cm before being absorbed. The externally detectible [sic] neutron flux into the laboratory from the cathode is thereby negligible[12].

A neutron with a wavelength of 10^-3 cm, or 10^7 angstrom, will have an energy of equivalent temperature of 10^-7 degrees K. (See neutron scattering conversion factors). A tenth of a million of a degree K.

That is not merely cold, it is freaking cold. I have not seen yet how W-L makes such supercold neutrons, but the question arises, “temperature with respect to what?” Temperature is a bulk characteristic, and I suspect that the very low temperature is related to an idea of a Mossbauer-like effect that ties the momentum of the neutron to the recoil of a much larger mass of particles. If I’m correct, then the neutron has very low velocity with respect to that mass. So let’s assume here, arguendo, that the ULM neutrons are created. (I could have calculated velocity instead, but I wanted to make the point as to how supercold this is.)

Then what? Here is the problem: the material of the cell is not so cold, and any individual neutron interaction will be with a particle that has a far wider range of momenta at the time of interaction. It is the relative momentum that will determine scattering cross section, not the supposed bulk properties.

So many of the neutrons will scatter, thermalizing and then becoming far more detectable.

This is really a draft, the beginning of an article, but I’m posting this immediately to solicit comment  from those far more knowledgeable than I. It takes a community. I will then edit this as needed. I may create a drafts page so that any comments may be referred to the version up when the comment was made.


Author: Abd ulRahman Lomax


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