Positron Annihilation Studies of Materials

AbstractPositron annihilation provides sensitive and versatile probe techniques in materials science that can characterize electronic structure and vacancy‐type, open volume, defects. The techniques utilize the information carried by the photons that result from the quantum relativistic process of the annihilation of a positron with its antiparticle the electron. For the implanted positron, the time to the annihilation event with a host electron depends on the electron density of the local environment probed. Annihilation normally results in the conversion to two anticolinear γ photons, this emitted radiation carries information on the momentum of the electron ‐positron pair at the instant of annihilation.The present article focuses on the standard e+annihilation methods applied to the study of defects in materials. Current developments in e+ annihilation are briefly described.