The association of hydrogen with nanometre bubbles of helium implanted into zirconium

Electron energy-loss spectroscopy (EELS) is used to investigate the association of hydrogen with helium bubbles in zirconium. Conventional EELS data yield a signal at 13.5 eV (similar to the hydrogen K-edge, 13 eV), which is spatially distributed around the peripheries of bubbles and may correlate with the concentration of hydrogen/deuterium in the material. Ultra-high energy resolution EELS yields a signal at 148.6 meV (comparable to a range of ZrH bonds, 130–156 meV) from a region containing bubbles and no visible hydrides. These signals are interpreted in the context of either bubble surface chemisorption or bubble stress field trapping mechanisms