Search for Neutrons from Deuterium - Deuterium Nuclear Reactions in Electrochemically Charged Palladium.

We report on a search for neutrons from dd fusion in Pd rods loaded electrochemically with deuterium. The rods were held in two electrolytic cells (D sub 2 O (99.5% D)+ 0.1 M LiOD) and placed before a 12.5 dia. x 12.5 cm Nal(T1) spectrometer system. The apparatus was housed within a polyethylene (PE) moderator, which was shielded on the outside with Pb and borax. A pair of plastic scintillator plates above and below the NaI (T1) vetoed cosmic muons. Fusion neutrons are moderated inside the PE housing, creating a slow neutron gas that can be detected by two gamma-ray producing reaction signals: (np gamma) capture in the PE (2.224 MeV gamma) and thermal neutron capture by Na and sup (127) I, yielding gamma-rays in the 3.5-7 MeV range. The background in the latter region is far less than the background below 3.3 MeV, which is dominated by natural ambient radioactivity. The overall neutron detection efficiency (measured with an Am-Be source) of this system is 0.015. In a four-week measurement we observe 0.007 n/sec/g Pd, compared to 2.6x10 sup 3 n/ sec/g Pd, claimed recently by Pons, Fleischmann, and Hawkins. Our result implies 2.2x10 sup (-24) (ddn) fusions/dd pair/sec, as compared to ~10- sup (-23) (ddn) fusions/dd pair/sec observed by Jones et al in a Ti electrode.