Thermal helium desorption spectrometry (THDS) is applied to measure helium binding to vacancies created by ion implantation of a Cu‐(100) single crystal. Helium is found to desorb from singly filled vacancies at 780 K (H‐peak). From multiply filled vacancies helium releases at 610 K (G‐peak). Helium desorption observed at 700 K, between G‐ and H‐peak, is attributed to the desorption of helium from He2V2‐complexes. The helium trapping as a function of ion energy is also measured. Subsequently experiments are done to measure the helium binding to defects created by cold work of single crystalline copper. As for molybdenum, no clear contribution of dislocations in the desorption spectra is observed. However, the interpretation of the desorption spectra is strongly hindered by surface trapping of helium, which is also observed for nickel.
The precipitation of low energy helium injected into molybdenum has been monitored by thermal helium desorption spectrometry (THDS). Precipitates nucleating at vacancies have been studied in the range from n= 1 to n=2500 He per precipitate. The behaviour of the growing precipitates with respect to helium trapping, self-interstitial capture and emission, and helium release is discussed against the background of results of TEM work done for precipitates with n >500 He. Evidence is found for (i) "trap mutation" at tz= 10 He, i.e. formation of bound self-interstitials around the helium filled vacancy, and (ii) emission of at least one of these "mutation produced self-interstitials" (MPI) at n-12 He.For larger precipitates (12 >20 He) the emission of single MPI is not apparent. At n= 1000 signs of helium binding to MPI-loops punched out by the precipitates are observed in the spectra.
Thermal Desorption Spectrometry (TDS) has been used to study the interactions of Self-Interstitial Atoms (SIA) with noble gas associated defects in Mo and Ni. Low energy heavy ion bombardment (100 eV Ar and Xe for Mo; 50 eV Kr for Ni) has been used to introduce SIA into the metals. Interactions have been observed of SIA with He n V ( V = Vacancy; n = 1 ..... 7) and Ar V n (n = 1, 2, -• • )in Mo, and with NeV in Ni. In all these cases the defects were found to be reduced by SIA capture. Substitutional atoms were converted into (at 300 K) mobile interstitials. For Kr in Ni no capture of SIA was observed. The results and their possible consequences for noble gas agglomeration in noble gas irradiated metals are discussed.
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