Ron Maimon's theory (2)

In a previous post, I attempted to provide a layman's overview of a theory put forward by Ron Maimon concerning what is generating anomalous heat in the palladium deuteride LENR experiments.  The theory, which I have nicknamed a theory of "Auger deuterons," nicely incorporates the primary elements of the signatures seen in many of the Pd/D experiments:

• Heat
• Broadband x-ray spectra
• Fast alpha particles and protons
• 4He off-gas
• Transmutations of various kinds

Part of the motivation for the earlier blog post was to get feedback from people on vortex-l, and as I hoped would happen, Robin, who is on that list, pinpointed several difficulties that needed to be addressed.  Here are questions from him (1 and 2) and me (3 and 4) that resulted from the thread:

1. How do two deuterons approach the Pd nucleus concurrently, as this seems a very unlikely thing to occur?
2. The d+d fusion cross section becomes negligible below 5 keV.  Assuming a loss of 400 eV per palladium atom that a 20 keV deuteron passes through as a result of interactions with its electrons, the energy of the deuteron will drop below the 5 keV threshold after passing through 38 palladium atoms.  In the unlikely event that it hits another deuteron head-on before that, even then a fusion is not assured.  So all-in-all the likelihood of a self-sustaining reaction seems small.  How can one be obtained under these circumstances?
3. The regular branches for d+d fusion are (a) d+d→t+p (50 percent), (b) d+d→3He+n (50 percent) and (c) d+d→4He+ɣ (almost negligible).  What causes branches (a) and (b) to be suppressed and branch (c) to become dominant?
4. When you have fast particles flying through a deuterated metal lattice, a particle is likely to bump into a deuteron, and it in turn will hit another deuteron. Occasionally a side reaction of branch (b), above, will occur, yielding a significant number of neutrons which would then exit the system.  But neutrons are only rarely seen and at levels barely above the sensitivity of the neutron counters.  For this reason Peter Hagelstein places a 20 keV upper limit on the energy of the particles in the system.  Ron's account involves alpha particles with energies of tens of MeV, so the lack of neutrons from side reactions on an order above that currently seen could be expected, presenting a challenge to be addressed.

The full vortex-l thread can be found here.  I am sure that the difficulties go back to my own understanding and have been anticipated by Ron.  I will be interested to hear how he addresses them, especially (3).

EDIT: Concerning items (1) and (3), above, Ron addresses these questions in his original physics.SE post:

The fusion of deuterons always happens through unstable intermediate states, and the cross section to alpha particle is only small because of the same non-relativistic issue. To get an alpha, you need to emit a gamma-ray photon, and emissions of photons are suppressed by 1/c factors. When there is a nucleus nearby, it can be kicked electrostatically, and this process is easier than kicking out a photon, because it is nonrelativistic (the same holds for an electron, but with much smaller cross section due to the smaller charge, and there is no reason to suspect concentration of wavefunction around electron density, as there is for a nucleus). 

The time-scale for kicking a nucleus is the lifetime of the two-deuteron resonance, which is not very long, in terms of distance, it is about 100 fermis, this is about the same size as the inner shell. If the deuterons are kicking about at random, this coincidence is not significant, but if the deuteron-hole excitations are banded, it is plausible that nearly all the energetic deuteron-deuteron collisions take place very close to a nucleus, as explained above. 

There are conservation laws broken when a nucleus is nearby. The nucleus breaks parity, so it might open up a fusion channel, by allowing deuteron pairs to decay to an alpha from a parity odd state. Such a transition would never be observed in a dilute beam fusion, because these fusions happen far away from anything else. This hypothesis is not excluded by alpha particle spectroscopy (there are a lot of relevant levels of different parities), but it is not predicted either.

This only hints at an answer to question (1), by saying that the banded state makes it "plausible" that the energetic deuterons will encounter one another near a palladium nucleus.

Ron Maimon's theory of Auger deuterons

There are plenty of theories available to explain some or most cold fusion experimental results, but none of them has gained general approval among cold fusion researchers. The rudiments of a less-known but interesting theory have been proposed by Ron Maimon, who up until the end of 2012 was an active participant on physics.stackexchange.com.  The theory goes well beyond my knowledge of nuclear physics, but I was able to get ahold of some details about it that make it more recognizable to a hobbyist like myself, which are mentioned in this Stack Exchange chat transcript.  Prior to the chat with Ron I participated in an interesting discussion with Robin van Spaandonk, on the Vortex list, about some of the details of the theory as set out in the reply to the physics.SE question linked to above.  Robin is knowledgeable about nuclear physics, and the discussion helped me to know what to ask later when I was talking to Ron.

The basic mechanism occurs when a K-shell electron is kicked out of its orbit around a heavy palladium atom in the metal lattice.  That in turn creates a hole which can decay in various ways; normally it will decay either through an electron from another orbital filling the hole with a subsequent x-ray photon emission or, alternatively, through the ejection of an Auger electron.  The energy involved in the decay of such a K-shell hole is on the order of 20 keV, an amount sufficient to cause two deuterium nuclei to fuse a significant portion of the time in a beam of deuterons.

Ron posits that when a deuteron is in the immediate vicinity of a palladium atom from which a K-shell electron has been ejected by action of an x-ray or a traveling alpha particle, the deuteron will preferentially receive the energy of the K-shell hole decay via electrostatic repulsion, thereby gaining 20 keV of energy.  This makes the deuteron in a sense an "Auger deuteron." Should it fuse with another deuteron, the Q value of the reaction will be a very large 24 MeV, which will be shared with the daughter alpha particle and the spectator palladium atom.  If I have understood Ron's account, there will be no gamma photon, as the reaction will have occurred close enough to the palladium atom for it to share in the momentum of the daughter alpha.  The fusion cross section will be enhanced in the case where two energetic deuterons approach a palladium atom simultaneously; at the "classical turning point," i.e., the point at which the electrostatic repulsion of the positively charged palladium nucleus will start to push the approaching deuterons away, they will be in close enough to one another, as Ron alludes to and Robin clarifies, for their de Broglie waves to overlap enough to possibly result in a fusion.

Occasionally a fast daughter alpha particle will interact with a spectator palladium atom, causing it to gain or lose some number of nucleons and resulting in a transmutation to another element.  This is understood to be a side channel and not the main source of heat. The reaction is sustained as a result of the energetic daughter alpha racing through the lattice, ionizing palladium atoms as it travels, triggering in turn the mechanism described above.  According to this theory, the things to look for during and after anomalous heat are x-rays, helium and transmutations certain numbers above and below the mass of palladium.

An issue that Robin had with Ron's theory is that he thought that the ionization caused by the traveling alpha particles would be too inefficient to result in enough K-shell holes.  But he also pointed out that, if something like this were happening, you might see a similar effect in the nickel/hydrogen system. In that case it would be the fraction of deuterium in light water interacting with energetic protons, rather than p+p fusion, that would be taking place.  If I have understood Robin, an attractive detail of Ron's Pd/D-focused theory is that it potentially provides a way to keep the energy needed for D-D fusion around long enough to sustain a continuous reaction.

Vortex-L temporarily down

The Vortex mailing list is a list that I've been following for over a year now.  The list was started in 1995 and is one of the best places for the general observer to get the latest news about cold fusion.  The subject matter ranges far beyond cold fusion, however, and gets into some pretty wild topics, such as the Papp engine and magnet motors, which can be quite entertaining to learn about.

Unfortunately the list was suspended recently after a prolonged dispute.  Hopefully it will be brought back up soon.

The Martin Fleischmann Memorial Project

At a conference this year, Francesco Celani, a cold fusion researcher, demonstrated a novel wire reactor apparatus.  The apparatus showed what Celani believes to be clear evidence of anomalous heat—more energy coming out of the device, over time, than has been put into it, a central claim of Fleischmann and Pons.

The Martin Fleischmann Memorial Project is a project that started up this year with the aim of assembling a kit that will replicate Celani's experiment.  Celani's device consists of a long glass tube with specially treated wire coiled around a rod of sorts contained within the tube (the composition of the wire is a secret).  The effect is seen when the glass chamber is filled with hydrogen and a current passed through the wire.  Once the Martin Fleischmann Memorial Project have the design worked out for their kit, they will make the kit available to universities and third parties for study.

The project's intention is to be transparent in everything they do, and in this spirit they're keeping a regular blog of their progress and are making their data available.  In one of their blog entries, they show a graphic of impedance in the wire versus the temperature in one of the thermocouples over a number of calibration runs.  I downloaded their data and put together the same graphic:

One detail that stands out right away is that they are smoothing their graphs somewhat.

The following columns are available in the calibration data sets:  Date, T_Board, T_Mica, T_GlassIn, T_Well, T_GlassOut, Pressure, Current Blue, Voltage Blue, Power Blue, Impedance Blue, Current Red, Voltage Red, Power Red, Impedance Red, T_Ambient, Pressure, Total Power, T_Mica Rise, T_GlassIn Rise, T_Well Rise and T_GlassOut Rise.

The blog entry with the graphic mentions that an error of +/-3 percent has been calculated with a 95 percent confidence interval from three identical runs (which statistic is being analyzed is not yet clear).  This error level means that they will be looking for at least 3W excess power.  I would like to try to duplicate their calculation of the error.

Details to be explained or addressed

I'm starting to get a sense of what I think might be going on in the LENR experiments.  The idea is that there's a photoelectric effect involving a gamma or an X-ray and an electron, which gives rise to a bosonic quasiparticle which can then combine with a free proton in the metal lattice and yield a neutron. An earlier post has already noted some difficulties in adopting an explanation that involves neutrons.

In addition, there are other details which may not seem contradictory to an account involving neutrons but which nonetheless need to be explained or addressed.  Edmond Storms mentions some of these details in his excellent paper, "A Student's Guide to Cold Fusion." For a Pd/D electrolysis experiment, these details include (possible explanations in parentheses):

• Lack of correlation between neutron detection and heat (neutrons were absorbed during heat generation and so could not be detected).
• Far too few gammas for generated heat, lack of correlation (gammas are also absorbed in the reaction).
• X-rays are not always detected in proportion to generated heat.
• High Pd/D average loading is usually required (high loading is a proxy for the flux of free protons through the nuclear-active environment).
• High Pd/D average loading is not always required (there are sufficient free protons in the nuclear active environment, despite the low loading).
• Current must be maintained for a sufficient amount of time, but this time can be short for thin layers of palladium and a long time for bulk palladium (there has to be 1, sufficient proton flux, and 2, an energetic photon that comes along for some reason to set off the reaction).
• Impurities can activate inactive palladium (the palladium is not what is involved in the reaction; it is a catalyzer).
• Success in getting a reaction depends upon the batch of palladium (there has to be something that gives rise to the right optical phenomena, e.g., microcavities).
• H2O contamination will stop a reaction (the atomic hydrogen does not ionize and prevents the deuterium from entering the lattice).
• A higher temperature causes the reaction to go more quickly.

There are details in other types of experiments that need to be addressed as well:

• There is an effective positive charge for hydrogen migrating through palladium in some electrodiffusion experiments (I have speculated elsewhere that it is atomic hydrogen and not ions that migrate).
• Energy and nuclear products have been seen when >1 MHz sonic waves are used to react deuterium with solid metals.

Challenges for neutron production

Any explanation for cold fusion that involves neutrons will run into a number of objections.  Edmond Storms sets out several of these objections in section 8.2.1 of his invaluable book, The Science of Low Energy Nuclear Reaction.  (I highly recommend this book to anyone exploring cold fusion.)  In that section there is a numbered list of considerations, and considerations 2 and 4 seem to involve in part a lack of observed beta particle emission.  I wrote Dr Storms and asked him about these two considerations, specifically, and the basis for concluding that beta particle emission is missing.  I wondered whether this conclusion was based on the CR-39 evidence, which involves detecting tracks left in a kind of plastic that is used in sunglasses.  This plastic is typically inserted directly into the electrolyte.  A method of detection along these lines is necessary because beta particles cannot pass through the walls of the closed systems that are used in the cold fusion experiments.

In his helpful reply, Dr Storms seemed to indicate that these considerations were getting at something else in addition to the lack of beta particle emission.  Here is the gist of what he said:

1. Occasionally neutrons are seen, but their levels are very low and their source unknown and unrelated to heat production.
2. The radioactivity expected when neutrons interact with their surroundings is easy to detect using a cheap Geiger-Muller counter and has been sought and rarely seen.
3. Neutrons are short-lived, with a half-life of ~ 16 minutes, so they must be constantly replenished in a sustained reaction.  This is not possible in ordinary materials.

Storms' points have obviously been given some thought, and I hope to learn more about each of them.  I understand that he discusses the low levels of neutrons that are occasionally seen in his "Student's Guide" and offers a possible explanation, so I will read that paper first before drawing any conclusions in the present connection.

Ionization of hydrogen isotopes

I'm redacting an email I sent to vortex-l and putting it up here, since the list appears to be down.

In a recent thread on vortex-l, Axil mentioned that tungsten has a low hydrogen permeability and that this causes problems for Brillouin's and Widom and Larsen's hypotheses. He provided some interesting links, and he appears to be correct about the permeability of hydrogen-1 in tungsten.

I find the low hydrogen-1 permeability an encouraging result, for roundabout reasons. A conjecture that I think we should consider is that ionization of the hydrogen isotope (hydrogen-1, hydrogen-2, etc.) is a requirement for a cold fusion reaction to proceed. One of the questions that has been bugging me is why hydrogen-1 appears to work well with nickel but palladium seems to require deuterium, and hydrogen-1, if anything, seems to interfere. This could be an overstatement; there have been many experiments, and I wouldn't be surprised if there is some countervailing evidence, but this seems to be the general trend of what is being seen, as far as I can tell.

The low hydrogen-1 permeability of tungsten lends credence to the notion that the size of the lattice (and, apparently, it's Miller number -- 100, 110, etc.) is a factor here. So we might guess that palladium allows for the diffusion of monoatomic hydrogen, but it does not yield high levels of hydrogen ions, whereas nickel perhaps does. The following link is suggestive concerning the migration of monoatomic hydrogen (rather than unshielded protons) in palladium:

http://pureguard.net/cm/Library/Palladium_Membrane_Purification.html

Like others, I think the heat-after-death effect, where a reaction continues after the current has been stopped, is not central to what is going on, so I see no strict need to require diffusion of hydrogen in the bulk of the cathode. Indeed, there is evidence that what is going on is a surface or near-surface reaction; the low permeability of hydrogen in tungsten seems to point in this direction as well. There is the question of the need for high loading in Pd/D electrolytic systems to see an effect; one possible explanation here is that you just need a high enough concentration of free deuterons on (or near) the surface of the cathode to see results in a situation in which we barely control the reaction, and high loading gives rise to this as a side effect, due to the desorption over time of large numbers of deuterons.

Ionization is also something that would happen in the glow discharge and electric arc experiments.

What role might ionization play? To pursue my pet hypothesis, perhaps you need an unshielded proton or deuteron in order for something to happen in connection with the its electrostatic charge. If bulk loading only plays an indirect role in specific systems and it was not needed in previous tungsten experiments because, for example, sufficient ionization was brought about through other means, it's not clear what the implications are for Brillouin's, Widom and Larsen's, or for that matter, Peter Hagelstein's hypotheses.