A STUDY OF THERMAL DESORPTION OF HELIUM FROM HIGH-PURE \alpha-Ti AND HYDROGENATED Ti SAMPLES

Helium ions have been implanted into highly pure \alpha-Ti and hydrogenated Ti samples with energy of 140keV and at dose of 5.2×10¹⁷He·cm^-2. The retained amount and depth pro-files of helium in the samples were determined by means of proton-enhanced-backscattering (PEBS) at room temperature. The changes of He peaks during isochronical annealing at 100, 200, 300℃,… were monitored in-situ by PEBS for groups of samples. The process of temperature ramping was not stopped until He peaks almost disappeared and hence the release curves were obtained. It was found that ～ 60% of helium was released at 200℃ for high-pure \alpha-Ti samples, whereas massive release occurred at 300℃ for the samples with H/Ti=0.9 and at 350℃ for the samples with H/Ti=0.2. The mechanism of He release and the effect of hydrogen were also discussed.