Trapping of deuterium in krypton-implanted nickel

Krypton ions with energy 600 keV were implanted in nickel to fluences of 2 x 1016 cm-2 under three different conditions. Deuterium was subsequently introduced into the implanted regions by electrolysis at room temperature. After the diffusible deuterium was permitted to escape, the 2H(3He,1H)4He nuclear reaction was used to analyze for the trapped deuterium during an isochronal annealing program. The region implanted at 1000C with no higher temperature anneal had the largest number of traps; the region implanted at 1000C and annealed for 100 min at 5000C had considerably less; the region implanted at 5000C had the least. Electron diffraction patterns confirmed the existence of solid crystalline krypton in all three regions. Transmission electron microscope studies revealed precipitates with an average diameter of 8 nm in the region implanted at 5000C. The two regions implanted at 1000C contained smaller precipitates. Trap binding enthalpies were obtained by math modeling. In addition to the traps with binding enthalpy of 0.55 eV reported earlier by other investigators for helium implanted in nickel, a smaller number of traps with binding enthalpies up to 0.83 eV were also found. The trapping of deuterium by various types of imperfections, including the solid krypton precipitates, is discussed