Enhancement of the electron screening effect for d + d fusion reactions in metallic environments

Abstract

PACS. 95.30.-k – Fundamental aspects of astrophysics. PACS. 95.30.Dr – Atomic processes and interactions. Abstract. – To study the electron screening of nuclear reactions in metallic environments, angular distributions and thick target yields of the fusion reactions 2 H(d,p) 3 Hand 2 H(d,n) 3 He have been measured on deuterons implanted in three different metal targets (Al, Zr and Ta) for beam energies ranging from 5 to 60 keV. The experimentally determined values of the screening energy are about one order of magnitude larger than the value achieved in a gas target experiment and significantly larger than the theoretical predictions. A clear target material dependence of the screening energy has been established. Introduction. – At sufficiently low projectile energies an enhancement of the cross-section for charged-particle–induced nuclear reactions can be observed. This is due to the shielding of the charges of reacting nuclei by surrounding electrons which leads to an increase of the Coulomb barrier penetrability and enhances the measured cross-section in comparison to the bare nuclei case. This effect, known as electron screening, was originally discussed for the dense