Feeding-in and blocking processes of MeV protons transmitted through silicon single crystals

Abstract

Angular and energy distributions of protons transmitted through thin Si single crystals have been measured as a function of the impinging angle between the beam direction and the {110} planar direction. The angular distributions have been obtained by means of a mobile small-acceptance angle (∼10 −7 sr) surface barrier detector. The investigation has been performed for different crystal thicknesses (3–7 μm) and beam energies (0.5−2.5 MeV). The observed anisotropies in the angular intensity distributions have been interpreted in terms of feeding-in and blocking processes. The relative contribution from each phenomenon is determined by the target thickness t, beam energy E, and angular position ϕ of the plane with respect to the beam direction through the combination ϕE/√ t, at least in the adopted range of the experimental parameters.