From: Eric Walker * I don't know whether Mills is avoiding disclosing testing done with rubidium or not. But I suspect that if he is still using potassium, he is seeing induced beta decay of the potassium, and that it is not more complex than this.
* There was an interesting paper from the early 1990's, if I remember correctly, in which a group was doing light water electrolysis with potassium and finding calcium. They noted that the experiment was similar to one of Mills or perhaps Thermacore. The group proposed proton capture in their own case, but I suspect the calcium came from induced beta decay of the potassium. Eric, Bush and Eagleton reported that calcium and strontium atoms are produced from K and Rb ions, respectively, in the electrolysis of light water with a nickel cathode. They used both SIMS and ICPMS. Both these papers should be in the LENR/CANR database. These are both very strong papers, however, I agree that induced beta decay is more likely than fusion, and Bush/Eagleton missed that important detail. This is especially true if UDH is being created. Long before the UDH would fuse, it would approach the alkali nucleus and disrupt an already unstable isotope, resulting in beta decay. The disruption is most likely magnetic – not electrostatic. (see http://link.aps.org/pdf/10.1103/PhysRevC.27.1199 http://arxiv.org/abs/1011.3776 and others. The near field of UDH is in the kilo-Tesla range. Here are the old papers on alkali transmutation: R. T. BUSH and R. D. EAGLETON, “Experiments Supporting the Transmission Resonance Model for Cold Fusion in Light Water: I. Correlation of Isotopic and Elemental Evidence with Excess Heat,” Proc. 3rd Int. Conf. Cold Fusion, Nagoya, Japan, 1992, p. 405, Universal Academy Press. R. T. BUSH, “A Light Water Excess Heat Reaction Suggests that ‘Cold Fusion’ May Be ‘Alkali-Hydrogen’ Fusion,” Fusion Technol., 22, 301 (1992).

