Comparative study of uniaxial channeling-blocking and single-alignment channeling backscattering—reversibility and defect analysis

Abstract

Scattering yields are examined for 200-keV proton channeling in silicon and gold under conditions of single and double alignment. Results are presented for 180° uniaxial channeling—blocking and 150° channeling—backscattering for nondamaged but thermally vibrating crystals (300 K). The analysis of the data is approached, however, from the point of view of the formalism required for decomposing an arbitrary mixture of interstitial and lattice-distortion-type crystal defects in order to assess the applicability of the reversibility rule of channeling and blocking to the defect analysis equations. In the limiting condition of thermal dechanneling it is observed that the equations are applicable only when the double-aligned spectra are corrected for the energy dependence of scattering into blocking configurations. The transformation is discussed in terms of scaling according to a set of energy-loss parameters that can be obtained from the scattered-energy spectrum. These procedures appear necessary since strict reversibility in channeling and blocking cannot be expected under conditions where electronic stopping introduces significant energy loss during penetration of the channeled beam.