Experimental Observation of the Thomas Peak in High-Velocity Electron Capture by Protons from He

Experimental angular distributions are reported for electron capture by protons of 2.82, 5.42, and 7.40 MeV from He. A clear peak in dσdθ appears near the Thomas angle of 0.47 mrad for the higher two bombarding energies, supporting the widely held belief that the double-scattering mechanism plays an important role for high-velocity electron capture.