Axial channelling of low-energy antiprotons

Abstract

Monte Carlo computer simulation of the passage of antiprotons and protons through a silicon crystal under axial channelling conditions is performed. The energy spectra and angular distribution of channelled protons and antiprotons moving along the (110) direction are calculated and compared. The projectile energy range is from 300 keV to several megaelectronvolts. It is shown that the energy loss corresponding to the maximum of the antiproton spectrum is close to the energy loss of particles moving in a random direction. Moreover, the most probable energy loss of the channelled part of the antiproton beam is slightly less than the random energy loss. The Barkas correction to the energy loss has little effect on the energy spectra of channelled particles and can hardly be studied with this type of experiment. The angular distributions of protons and antiprotons differ considerably. The characteristic features of the angular distribution may serve as evidence of channelling of low-energy antiprotons.