Twelve days ago I wrote: Presumably the experiment ran for a while, but nonetheless one gets the > impression that the tritium is more than simply the result of some side > reaction, and it looks like the main daughter in this case. >
This was in connection with a slide presented by Michael McKubre at the meeting in Brussels convened to take a look at work on the Fleischmann and Pons effect. The slide summarized a replication by SRI of an experiment by Arata and Zhang using a unique "DS" cathode, where a palladium outer shell was filled with palladium black and then the whole thing electrolyzed in LiOD and LiOH. I thought the slide was very interesting because it indicated that SRI had measured 10^15 atoms of tritium, and I wondered whether it was the main daughter in that reaction. I have since read more about that replication in an appendix to a review paper that was prepared for the U.S. Department of Energy review in 2004. It seems the 10^15 atoms of tritium were generated over a period of 86 days. The amount was very significant -- the original amount was about 0.05 percent of the final amount. But the final amount was not at a level to produce the excess heat SRI saw, and it was not even at a level to be measured in their calorimeter. In that replication, they did not find the daughter product that was causing the heat; they found no 4He, and the 3He was at levels and in a spatial distribution consistent with tritium decay. So the source of the excess heat in that replication was unaccounted for. The appendix to the DoE paper mentions three possible sources of the excess heat, and the last one is that the heat was produced by 4He formation at the surface of the cathode, rather than within it, and, as a consequence, the 4He vented into the atmosphere. This possibility is an interesting one, because it is consistent with the hypothesis that the tritium was also produced at the cathode surface and then migrated (as hydrogen can be expected to) into the cathode under the voltage that was applied during the electrolysis. In this scenario, one source of the tritium would be from 6Li(d,t)5Li reactions from prompt d's shooting into the electrolyte. (Ed has mentioned another possibility -- a d+e+p reaction.) Eric
