Study of the structure of axial and planar aligned backscattering spectra in vanadium

The planar to axial transition for channeled 1.8 MeV He + ions has been studied. The transition between the planar mode and the axial mode appears in a very narrow angular range. The planar spectra were fitted using a stochastic model described previously. In order to check the hypothesis that the structure observed in axial spectra is of planar origin, the axial spectrum was fitted using a linear combination of the spectra obtained for the two major planes which intercept along the axis. The fit obtained is rather good and leads to the conclusion that the oscillations observed in axial spectra can be due to particles non-channeled with respect to the axis but sensitive to a planar potential and hence having quasi-periodic oscillating trajectories.