Pfc/ja-89-24 Rev

Fleischmann, Pons, and Hawkins (FPH)1, 2 recently announced that significant fusion heating was occurring in their cold fusion experiments. As compelling evidence of fusion processes, they reported the detection of 2.2 MeV y rays that result from neutron-capture-on-hydrogen. We have carefully analyzed the published y-ray spectra of FPH. We have also performed detailed terrestrial y background measurements and neutroncapture-on-hydrogen experiments. From our analyses we conclude that the FPH y line is specious on the basis of three quantitative considerations: (1) it has a line width a factor of 2 smaller than the detector instrumental resolution would allow at 2.2 MeV; (2) there is no evidence of a Compton edge at 1.99 MeV (i.e., 2.22 MeV 0.23 MeV), and this edge should be distinctly prominent; and (3) FPH's estimate of the neutron source rate, based on their purported y signal, is a factor of 50 too large. Additionally, from terrestrial y background considerations, we argue that FPH's y "line" actually resides at 2.5 MeV rather than 2.2 MeV. Based on these arguments, we conclude that the y signal of FPH cannot be the 2.2 MeV neutron-capture-on-hydrogen y ray. We can offer no plausible explanation for the feature, other than it is possibly an instrumental artifact unrelated to a y-ray interaction.