Positron Annihilation Spectroscopy

A review of recent developments in positron annihilation spectroscopy (PAS) is presented. Positron annihilation from a radioactive source by injecting a positron into a solid and its entrapment in lattice defects such as vacancies to yield detailed defect-specific information is described; the experimental techniques including positron lifetime spectrometers which provide information on the defect annealing state of a sample, and angular correlation which provides detailed electronic structure of Cu or Al are described. The Doppler broadening can be measured by means of an energy sensitive PAS detector using Ge(Li) or intrinsic Ge. PAS techniques are used to study the shapes and dimensions of Fermi surfaces in metals from discontinuities in the angular correlation curves of single-crystal samples; they have also been utilized for studies of vacancies, vacancy clusters, and dislocation lines and jogs in metals and alloys.