Exchange and reduction of retained hydrogen isotope by glow discharges

Following hydrogen glow discharge of stainless steel, a deuterium glow discharge was conducted to exchange the retained hydrogen in the stainless steel for deuterium. During the deuterium discharge, about 60% of the retained hydrogen desorbed. The amount of retained deuterium was 1.5 times larger than that of desorbed hydrogen. After the deuterium discharge, glow discharge cleaning with inert gas was conducted and the amount of the removed hydrogen isotope was evaluated. The removal ratio of hydrogen isotopes in the stainless steel was the largest during He glow discharge, and the smallest during Ar glow discharge. The removal ratio of retained hydrogen isotope by neon discharge cleaning did not change although sequential discharges of deuterium and neon were conducted repeatedly.