Strongly Enhanced DD Fusion Reaction in Metals Observed for keV D⁺ Bombardment

Abstract

The excitation functions of the yield of protons emitted in the D(d,p)T reaction in Ti, Fe, Pd, PdO and Au were measured for bombarding energies between 2.5 and 10 keV. It was found that the reaction rate at lower energies varies greatly with the host materials. The most strongly enhanced DD reaction occurs in PdO. At E_d=2.5 keV, it is enhanced by factor of fifty from the bare deuteron rate and the screening energy deduced from the excitation function amounts to 600 eV. An enhancement of this size cannot be explained by electron screening alone but suggests the existence of an additional and important mechanism of the screening in solids.