Backscattering, trapping and post-bombardment thermal release of 100 eV to 2 keV D 2+ ions at a Mo surface

Abstract

D 2 + ions in the energy range 100 eV to 2 keV have been injected into polycrystalline [preferred (100) orientation Me] at 250 K. Measurements of total backscattering yield and ion trapping coefficient were studied as functions of ion energy and fluence. Post-bombardment gas evolution was also recorded during linear rate of rise tempering and the rates of gas release monitored mass spectrometrically to determine evolution kinetics and activation energies. The measured total backscattering yields were significantly lower than theoretical calculations based upon a randomised atomic target array but agreed more closely with estimates based upon binary scattering from a simulated single crystal. Activation energies for D 2 evolution suggest that D is trapped atomically in the Mo and recombines within the bulk or after diffusion to the surface.