Quantitative study of the transmission of axially channeled protons in thin silicon crystals

The azimuthal distributions of protons transmitted through thin silicon single crystals near the $〈110〉$ axis were measured using a two-dimensional position-sensitive detector. The data are composed of ringlike distributions with strong azimuthal and transverse energy dependence. The azimuthal distributions are compared with theoretical predictions based on the random string approximation using different forms of the interatomic potential. "Blocking" in the transverse plane is also observed. In addition, from an analysis of the radial spreading of the distribution the effects of inelastic scattering in the transverse plane are clearly seen.