Radiation Damage and Gas Diffusion in Molybdenum Under Deuteron Bombardment

Abstract

The release of gas from metals after implantation has been studied for many years⁽¹⁾. A case of interest both from a fundamental point of view and from the application to controlled thermonuclear experiments is the bombardment of metals with hydrogen ions. This case is unique because of the high diffusion coefficient and high solubility of hydrogen in metals. In previous papers we have examined in detail the trapping and release of deuterium in nickel.^(2,3) It was shown that the release rate is much less rapid than expected on the basis of thermal diffusion and there is considerable evidence that radiation damage by the incident ions produced trapping sites which inhibited subsequent diffusion by the implanted gas atoms. Similar evidence has been obtained for the helium tungsten system by Kornelsen⁽⁴⁾ who was also able to identify the types of defect responsible for sites of different binding energies. In the investigation of nickel, estimates were made of the binding energies of different sites and their population as a function of incident ion dose.