The form of the defect clusters produced in copper by Cu+ ion irradiation

A detailed electron microscope study has been made of the damage produced in copper by Cu+ ions. 30 kev and 90 kev Cu+ ions give rise to point defect clusters having a structure based on the vacancy type Frank sessile loop with Burgers vectors a/3〈111〉 there is evidence that parts of the circumference of many loops are dissociated into stair-rod dislocations and Shockley partials according to a mechanism proposed by Silcox and Hirsch (1959). This dissociation gives rise to areas of stacking fault on {111} planes other than that of the loop plane, and in the case of a triangular loop can produce a stacking-fault tetrahedron, though such defects have not been observed in Cu+ ion damaged copper.