Effects of Positron Diffusion and Its Application in Composite System

摘要

The effects of positron diffusion on the measured S parameter have been investigated by a point- source diffusion model and a δ function method. Firstly, the theoretical analyses of the effects are presented for the samples of a homogeneous semi-infinite medium and a film of definite thickness. Then the results are used to analyze the S parameters in several composite systems and interface models.