Multiple scattering and planar dechanneling in silicon and germanium

The dechanneling of MeV protons from the planar channels of silicon and germanium is investigated. The backscattering technique and transmission technique for measuring the dechanneling rate are compared and show good agreement. The data are treated in the framework of a diffusion model which describes the observed energy dependence of the dechanneling length. Various physical mechanisms which contribute to the diffusion are discussed and estimated. Direct measurements of the multiple scattering in the channels are compared to estimates of the diffusion constants.