Observation of planar oscillations of MeV protons in silicon using ion channeling patterns

This paper describes the observation of {110} planar oscillations of 3 MeV protons transmitted through a 0.5 mu m thick [001] silicon crystal using ion channeling patterns produced on a fluorescent viewing screen. Gradual variations in the crystal thickness allowed the exit angular distribution of the protons to be sampled al different depths into the crystal, revealing effects due to the coherent planar oscillations. This work necessitated the use of a focused MeV proton beam from a nuclear microprobe to generate channeling patterns from selected, micron-size regions and the necessary ion optics are developed here. The recorded channeling patterns are interpreted with the help of Monte Carlo computer simulations.