Dual ion beam study on deuterium permeation

The D permeation rate under bombardment of 50 keV D+ was measured at 5000C for Type 316 stainless steel which was pre-irradiated by 320 keV He++. In addition, the D permeation rate was also measured during simultaneous bombardment of 57.5 keV D+ and 280 keV He++ at 4420C. By pre-irradiation of 3 x 1017 He++ cm-2, the D permeation rate was reduced to about 1/4 of that without He++ irradiation. It was also found that a reduction of D permeation rate to about 1/3 occurred by simultaneous He++ irradiation of 1.3 x 1014 ion/cm2 s-1 in addition to the pre-irradiation effect. The change of the diffusion constant by the He++ irradiation was also evaluated with a computer code, which was developed to solve the diffusion equation by the Crank-Nicolson's method. (orig.)