Dechanneling of MeV Protons from Axial and Planar Channels of Germanium Crystal

Abstract

Energy spectra of protons backscattered from the surface of germanium single crystals are measured. The dechanneling rate of channeled protons into random direction and the stopping power ratio of the aligned to the random beam are obtained. The stopping power ratios for 1.5 MeV protons in the ⟨112⟩, ⟨111⟩, and ⟨100⟩ directions are 0.31±0.04, 0.40±0.06, and 0.43±0.06 respectively. The dechanneling rate of 1.5 MeV protons at the axial channel in which atoms in the row are uniformly spaced is proportional to the reverse of the square of the critical angle. The theoretical values of the dechanneling rate are calculated using the diffusion model and compared with the experimental valules. The experimental dechanneling rate in the ⟨111⟩ direction is considerably lower than the theoretical value.