Enhanced hydrogen trapping due to He ion damage

Single crystals and rolled foil of Mo with and without predamage by 11 or 18 keV 4He at room temperature have been injected with 8 or 16 keV H and D isotopes. The H depth profiles and the total D retention were measured by nuclear micronalysis techniques. A strong enhancement in the trapping of hydrogen isotopes after He predamage over Mo without predamage is observed and the H depth profiles scale with the He ion energy. Cold work increases the D trapping in the absence of He damage but after 3 x 1015 He/cm2 predamage little difference remains in the total trapping for single crystals and rolled foil. The release of the D upon annealing due to detrapping occurs primarily between 100 and 4500C. A similar fractional reduction in trapping is observed for elevated temperature D injection as is found in the anneal to corresponding temperatures of room temperature injected samples. (Auth.)