Nigel With water, there is the phenomenon of “proton hopping” even without cavitation.
The Hagelstein paper you cite proposes a neutron analog of electron hopping in semiconductors. This means that there are two natural phenomena on which to model neutron hopping. Protons hop from one water molecule to another naturally and consequently the principle of proton mobility in water has been known for 200 years ... now called the Grotthuss mechanism – but all attempts to split water more efficiently by using it have failed. It is a very fast mechanism and apparently recombination is too rapid to make it useful. https://en.wikipedia.org/wiki/Grotthuss_mechanism But the Grotthuss mechanism could be understood to provide a closer analogy to neutron hopping, since the mass difference is small between the two, with the huge advantage of the neutron having no difficulty with the Coulomb barrier. Radiation in the range of 1-5 keV is surely evidence of some type of LENR but not cold fusion. It is too bad that the two are conflated. From: Nigel Dyer One of the systems mentioned in Hagelstein's 2015 paper (http://www.currentscience.ac.in/Volumes/108/04/0601.pdf) is the Vysotskii system where what appears to be a coherent collapse of cavitaion bubbles causes a shock wave to travel through a metal plate and generate a very sharp pulse of 1-5keV X-rays from the metal surface on the other side. I have just come back from a conference where Vysotskii presented this. I felt that it was very clever and appeared to show some very interesting coherent energy conversion phenomena, but there did not appear to be any evidence of LENR Nigel JonesBeene wrote: Hi Robin The neutron “hopping” modality is indeed one way that gain could happen. In fact you are probably referring to Hagelstein’s 1993 paper where he introduces this concept wrt palladium. I do not think he was envisioning iron as the active metal at that time. Perhaps he will be reminded of this possibility. I like it but it also demands that the 2.4 MeV gamma is attenuated via the down-conversion aspect – so there are two miracles involved. … or do you get both miracles for the price of one when you have up and down conversion together <g> ???