EVIDENCE FOR A TARGET-MATERIAL DEPENDENCE OF THE NEUTRON–PROTON BRANCHING RATIO IN d + d REACTIONS FOR DEUTERON ENERGIES BELOW 20 keV

摘要

Angular distributions and the neutron–proton branching ratio of the mirror reactions 2H(d,p)3H and 2H(d,n)3He have been investigated using different deuterized metallic targets at projectile energies ranging from 5 to 60 keV. Whereas the experimental results obtained for Al, Zr, Pd, and Ta targets do not differ from those known from gas-target experiments, an enhancement of the angular anisotropy in the neutron channel and a quenching of the neutron–proton branching ratio have been observed for Li and Sr targets at deuteron energies below 20 keV. Both effects can be explained assuming an induced adiabatic polarization of the reacting deuterons in the crystal lattice.