Energy and flux limits of cold-fusion neutrons using a deuterated liquid scintillator

Deuterated liquid scintillator detectors (NE230), which give excellent n/γ discrimination and provide a direct measure of the neutron energy spectrum, have been used to search for 2 to 3 MeV neutrons produced in d+d cold fusion. The apparatus consisted of an electrolytic cell using high-efficiency inverted-well geometry. Several samples of annealed Pd wire and a Pd casting (up to 13 g) were studied over a period of several weeks. An upper limit of ≤${10}^{\mathrm{-}3}$ fusion (n/s g) Pd was obtained corresponding to ${10}^{\mathrm{-}24}$ fusion (n/s) dd pair in our samples which excludes most of the reported positive results. Several sources of spurious signals, which could closely mimic signals from fusion neutrons, were also observed.