[Note for new readers: This blog is part of the New Energy Times Web site and News Service. Readers can find out much more about LENR from our home page.]
I received a question from a New Energy Times reader a few days ago:
“What exactly is causing the energy to be produced in the LENR reaction according to the Widom-Larsen theory? Is it energy produced due to the transmutation of elements, or something else entirely?”
According to the Widom-Larsen theory, the reaction chain includes this four-step process:
I describe this process in my article “Widom-Larsen Theory Simplified” as well as in the chapter I co-wrote with Joseph Zawodny of NASA for the Wiley Nuclear Energy Encyclopedia.
Let’s first answer a question the reader didn’t ask: “How much energy is required to initiate the reactions and where does it come from?”
In experiments with hydrogen, there is an energy cost of 0.78 MeV to create the neutron that initiates the reaction chain and each subsequent neutron that is used. This takes place in step 1 of the Widom-Larsen theory. In the case of deuterium, there is a cost of 0.39 MeV to initiate the reaction chain and each subsequent neutron that is used.
Each of steps 2 – 4 in the Widom-Larsen theory release energy. According to Larsen, these may include neutron capture processes (that create gamma rays which are converted into infra-red heat energy by nearby heavy electrons,) alpha decays, beta decays, beta-delayed neutron emissions and beta-delayed alpha decays among others. Different values of energy release are associated with each process and each set of particles involved in the reaction network.
These are all well-known, conventional nuclear physics processes and the values can be found in textbooks and online tables such as the Brookhaven National Laboratory Q-Value Calculator.
These reactions take place in a complex network of possible reaction pathways. In the diagram below, taken from Larsen’s Sept. 3, 2009 slides, one of the many reactions shows a carbon-12 atom capturing a neutron and going to carbon-13. This releases 5.0 MeV of energy through the neutron capture process.
But nobody has even seen carbon-14 in LENR so it is very unlikely that the reaction chain stops in the neighborhood of carbon-13 or carbon-14.
If the reaction chain goes through seven steps, it can end up as helium-4, which has been seen many times.
The final step in this chain shows nitrogen-17 undergoing a beta-delayed alpha decay to helium-4. This releases 2.3 MeV of energy in that single step. This particular chain, from start-to-finish, C-12 to He-4, via N-17, is only one of many possible pathways. In this network path, the total energy release is 39.9 MeV, which accounts for the cost of the neutrons.
Readers who are ready for more may wish to look at Larsen’s Sept. 3, 2009 slides pages 11-12 and June 25, 2009 slides, pages 45, 46, 50 and 62-64.
A good resource to learn about the Widom-Larsen theory is my WL Portal page.
If neutrons are present during the reaction, is anyone looking to ‘seed’ an experiment with an isotope with a very high neutron cross-section, then detect the distinct gammas that would be produced? Would this not be a sound scientific means to examine the WL theory? If one suspects an intermediate stage in a reaction, then one should, ordinarily, set about trying to detect the intermediate stages.
Received via e-mail:
The reactions 2a and 2b (weak interactions) give released energy (mass defect) mostly to neutrino, so that we see no heat deposit in matter used in the experiment.
The supposed neutron capture reactions, 3; (Z,A) + n-ULM: produce for many cases of target nuclei exothermic (mass defect) energy:
In competition of 1) prompt gamma-rays from the intermediate compound nucleus M(Z,A+1: Ex)* making electromagnetic (EM) transitions (E1, E2, E3, M1, M2, M3) to lower excited states and finally to the ground state M(Z,A+1:Ex=0), and 2) break-ups by emitting plural particles (p, alpha, n, 2n, etc.). So, this may be energy source of heat deposit.
Prompt gamma-rays should almost leak from the reaction cell (the W-L hypothesis of complete absorption by “heavy electrons” is out law of nuclear and radiation physics, namely nonsense.), so that net heat deposit in a small CF/LENR cell does not happen. Heat deposit by charged particles, by break-ups of M(Z,A+1:Ex)*, in their slowing down in matter has possibility (W-L did not acknowledge it).
If the ground state M(Z, A+1; Ex=0) is radioactive isotope; the reaction 4: EC(electron capture to RI nucleus), e+ (positron) and e- (beta) decay processes emit less energy, which is however carried off mostly by neutrino to the universe (no heat deposit).
We know (for instance, see ENDF/B-6 file by BNL) that neutron capture cross section at low (less than 0.1 eV) energy is inversely proportional to neutron velocity v, namely = C/v, with constant C. = = C-times-No-times-n-density, which is independent of neutron velocity.
Therefore, W-L assertion that ULM-n is totally absorbed due to low velocity is WRONG! Instead neutron capture rate is constant for neutrons less than 0.1eV: it is common sense in Fission Reactor Physics.
There are other mistakes in W-L theory as I criticized in my review Cold Fusion Frontier 2011:
http://jcfrs.org/file/CFfrontier2011.pdf
So, I think the W-L theory is wrong in many ways, especially in quantitatively estimating weak interaction rates, neutron reaction rates, their final state interactions. I hope they will elaborate such cheating parts.
Regards,
Akito Takahashi
Osaka, Japan
Received via e-mail:
I noticed Akito included the linked post (as a comment) that seems to very directly and technically, in a detailed fashion, dispute some of the assertions and assumptions made by Larsen in the WLT. I also noticed that neither you or Larsen has responded to that post, which is disappointing. I’ve also found other, very detailed questions about specific processes in WLT in comments of other posts, which likewise, had no response. With respect to Akito, he offers a link to a journal where he more fully disputes WLT. Are these opposing views such as his available on your website for readers to investigate and discern for themselves? Are there many more like it? I had been led to believe that no researcher had come out with credible arguments against WLT, but this post seems to dispute what I’ve been led to believe from Larsen’s comments and on your site.
Although I can come no where near understanding the physics of his arguments, it seems to me that it is very well thought out and detailed in a very specific fashion, and that all of these-type arguments should be brought to the forefront and rebutted by you (or more importantly) Larsen on your website. Such intellectual debates should strengthen WLT and weaken the opponents if WLT represents sound science. With the level of confidence shared by you and Larsen, I would expect immediate responses to such attacks against the validity of WLT.
I had been led to believe in my personal conversion with Larsen that no one had successfully rejected his theory in a scientific manner. Maybe Akito’s rejection is not a sound scientific rejection, but the lack of a rebuttal certainly leaves one wondering.
Greg from Tennesse
Hi Greg,
Thank you for this very important comment. Scientists are not always the best communicators, particularly when they are under fire from every direction. Often, in such unusual cases, they do not know when it is best for them to speak up and when it is best for them to shut up. This would be true for any person who suddenly becomes the object of media attention. Even for me, I too do not always have complete clarity on what is appropriate to publish as you will see in my next comment. I strive to do my best and learn as I go.
I spoke with Larsen this morning. It is appropriate and helpful that he and I provide some response to you and all readers. Please let me know right away if the following statement does not completely satisfy your concern. There is certainly more that I can say, but I’d like to first see if you understand this without me saying more.
Let me point out one fact. You are mistaken that Takahashi has published his comment in a journal. JCFRS is the Japan Cold Fusion Research Society, an organization which hosts LENR conferences in Japan. Takahashi’s paper appears to be part of a conference proceeding.
SBK
Larsen is aware of Takahashi’s comment on this blog. Larsen was also aware of the dozen informal comments about the Widom-Larsen theory that New Energy Times solicited and published in 2008. In hindsight, it was unwise and inappropriate for us to solicit scientific critique in that manner.
In response to my inquiry today, Larsen has advised me that he will not be engaging in e-mail or blog warfare with competing theorists. He advises people who believe they have substantive comments to submit their thoughts to a peer-reviewed journal and he and his coauthors will decide whether their publication merits any reply.
For Larsen, qualified journals do not include Naturwissenschaften*, the Journal Of Condensed Matter Nuclear Science, Infinite Energy magazine, and any other scientific publication that would not be recognized by mainstream physicists as a credible publication.
I have not arrived at a final conclusion whether it was wise and appropriate for me to publish Takahashi’s comment here.
* Multiple conflicts of interest exist with Naturwissenschaften. All LENR papers submitted there are communicated through (or rejected by) Edmund Storms. He has consistently and publicly (in New Energy Times, World Scientific and the American Chemical Society) demonstrated a bias against the Widom-Larsen theory. He also considers himself to be a competing theorist.
SBK
Hi Greg,
I have arrived at some additional clarity.
You and I, lay people, have little ability to know when one theoretical physicist is blowing smoke and another is not. Because of our lack of specialized expertise, we can easily be manipulated to provide or deny popular support for something when, if fact, knowledge of the truth would have us do otherwise.
For this reason, high-level scientific argument – particularly with theory – is best left to reputable journals. Additionally, for the lay public, third-party references from independent sources who are either qualified, or have the means to consult with qualified experts, are valuable for our individual assessments.
I now think the process of evaluating competing theories by academic bloodbath has little utility. That is why, instead, I am enthusiastic about providing a platform for competing theories to show their best face. Let the competition be based on the demonstration of merit. I cannot devote time to all of the other theories, but I will put some attention on the Hagelstein ideas. McKubre seems to think that his colleagues’ ideas are the best explanations of LENR.
In the case of Widom-Larsen, I have noticed something profound: No published arguments from mainstream theorists. Only one published argument from a cold fusion theorist. Lots of unpublished noise from many cold fusion theorists.
SBK
It would help to have some historical perspective:
“Perhaps we have a theory that explains all the anomalous phenomena. The transmutation observed from Yasuhiro Iwamura [Mitsubishi Heavy Industries] are explained without the problematic multiple reactions of Takahashi.”
Source: “Lino Daddi” on 11/05/2005 22.06.52
Subject: miniatomi
Il presente messaggio inviato a quel ristretto gruppo che in passato si interessato alle reazioni p+e=n. Ricorderete i miei tentativi di spiegare i fenomeni CF e LENR mediante l’ipotesi dei miniatomi (FUSION TECHNOLOGY vol. 39, n2 pag 249 (2001). Ebbene, ora abbiamo la teoria di A.Widom e L.Larsen, pubblicata in tempo reale sul sito INTERNET http://xxx.lanl.gov/PS_cache/cond-mat/pdf/0505/0505026.pdf. Non fa ricorso ad ipotesi ad hoc ma solo a teorie gi accettate relative all’elettromagnetismo. Nelle references figurano Autori di tutto rispetto, Nobel compresi, e riviste indiscusse, soprattutto il Physical Review. Cito, Landau, Berestetskii, Schwinger ed il nostro Bertin.
I miniatomi si formano per effetto elettromagnetico quando idrogeno o deuterio purissimi sono depositati su superfici solide. Il rapporto di riduzione del raggio di Bohr arriva a 20, grazie all?AUMENTO DI MASSA DELL?ELETTRONE. La formazione di neutroni (vedasi don Borghi) sembra finalmente giustificata.
Chi interessato alle questioni teoriche potrebbe perderci qualche giorno di studio. Forse siamo alla teoria che spiega tutti i fenomeni anomali. Sono giustificate anche le trasmutazioni osservate da Iwamura, senza le problematiche reazioni multiple di Takahashi.
Ciao, Lino