Position dependent stopping power for axially channeled 10 to 160 MeV alpha-particles in silicon

Abstract

The slowing down of highly energetic charged incident along major crystallographic directions of a crystal is mainly due to conduction electrons, valence electrons and the local electron density due to inner shells at the position of the moving charged particles. Under channeling conditions the number density of atoms of the target seen by the projectile is slightly different from the bulk density of atoms. So the contribution of the valence electrons to the stopping power due to collective plasma oscillations will be different for the channeled and the random impact. Slater-type orbitals are used to calculate the local electron density due to the inner shells, and the cylindrically symmetric charge density around the channel axis due to all the six strings is obtained in the continuum approximation for the 〈110〉 axial channel is a diamond structure crystal. Using the above formulation, the position dependent electronic stopping power is calculated for 10 to 160 MeV alpha-particles channeled along the 〈110〉 axis in silicon, and the results thus obtained are compared with the experimental and theoretical results available.