INVESTIGATION THE EFFECT OF LATTICE DISORDER ON THE PENETRATION OF CHARGED PARTICLES THROUGH THE OPEN CHANNELS OF MONOCRYSTALLINE MATERIALS

Abstract

In the present thesis an attempt has been made for characterizing the disorder which may occur in crystal lattices during irradiation experiments or due to exposition to radiation sources . This has been done by studying the effect of lattice disorder on the penetration of charged particles through the open channels of single crystal materials. The three most probable types of lattice disorder according to the order oftheir configuration stability are: 1- Dumb-bell configuration (DBC). If the extra atom 1s

accommodated by sharing a site with another atom, the axis ofthe pair lying along a (100) direction. 2- Body-centered interstitial (BCI). Here, the extra atom occupies the largest space in the fcc unit cell. 3- Crowdion. In this case, a long-range relaxation occurs along a

(100) close backed row. Neighboring rows are little affected.

The study covered two types of lattice disorder that may occur in face­ centered cubic (fcc) crystals in a stable configuration namely, dumb-bell configuration (DBC) and body-centered interstitial (BCI)