1.7.2.2 Average displacement energy

This chapter discusses on average atomic displacement energy). In analytical displacement models, the effective displacement energy at high recoil energies is equated to the displacement energy, averaged over all lattice directions. This quantity average atomic displacement energy can be obtained from electron damage rate measurements on single crystals or on polycrystals. The values of average atomic displacement energy and values of effective displacement energies derived from neutron irradiations are tabulated. Resistivity per unit concentration of Frenkel pair values are used for the evaluation of effective displacement energy. Damage rate measurements with ions or neutrons irradiations show that at high recoil energies, effective displacement energy is no longer constant but exceeds atomic displacement energy considerably.