A description of bubble growth and gas release during thermal annealing of helium implanted copper

Abstract

This paper describes an investigation into the migration and coalescence of equilibrium bubbles in helium implanted copper. Using computer simulation methods, the results indicate that when the swelling averaged over the implant depth approached 12%, the subsequent migration and coalescence leads to the unexpected formation of relatively massive bubbles with radii of the order of the helium range (∼130 nm), some 10 times the average bubble radius. Such behaviour would appear to provide an explanation for the surface pores and the large helium loss during annealing observed in the experimental results of Escobar Galindo et al. [Nucl. Instr. and Meth. B, in press].