Thermal desorption of deuterium from polycrystalline nickel pre-implanted with helium

The thermal desorption technique has been used to study the trapping of deuterium atoms in high-purity polycrystalline nickel pre-implanted with helium from 1 × 1019 to 5 × 1020 ions/m2. The effect of post implantation annealing at 703 K and 923 K on the desorption behavior was investigated. Measured values of the total amount of detrapped deuterium (QT) and helium concentration were used in a computer simulation of the desorption curve. It was found that the simulation using one or two discrete trap energies resulted in an inadequate fit between the simulated and the measured data. The binding mechanism is discussed. An effective binding energy, Ebeff, was estimated to be in the range of 0.4–0.6 eV. Deuterium charging appears to stimulate a release of helium at a relatively low temperature.