SCATTERING OF PIONS AND CHANNELED MUONS BY IMPURITIES IN SINGLE CRYSTALS

Abstract

The possibility of pions and muons being used as probe particles for defects studies in materials research has been investigated for the past thirty years or so. We discuss here the similarities of π+ and µ+ with positrons and tritons so that they can be treated as light hydrogen isotopes. Incident pions occupy a lattice site (substitutional or interstitial) and then decay into muons of energy 4.12 MeV which undergo channeling effects. The scattering cross-section of pions in tantalum single crystal with oxygen impurities has been evaluated applying Born approximation and using a double screened potential. The same calculation is applicable for muons after making some relativistic corrections. This model should also be applicable in various other situations where dechanneling by heavy ion impurities existing in multiple charge states takes place in an otherwise perfect single crystal.