Comparing deuterium retention in heavy ion damaged tungsten measured by glow discharge optical emission spectroscopy, nuclear reaction analysis and thermal desorption spectroscopy

Abstract

Hot-rolled tungsten specimen were irradiated with 5 MeV gold ion and loaded with deuterium plasma sequentially. Deuterium retention was examined by glow discharge optical emission spectroscopy, nuclear reaction analysis and thermal desorption spectroscopy. The deuterium depth profiles obtained by nuclear reaction analysis show that deuterium concentration increases significantly after irradiation, and damage region could uptake most of deuterium. The results of thermal desorption spectroscopy demonstrate that heavy ion damage can produce a large number of defects which could trap deuterium. Significant deuterium saturation was observed with damage level above 0.4 dpa. Furthermore, the depth profile and total inventory of deuterium show that the result measured by glow discharge optical emission spectroscopy is in good agreement with that by nuclear reaction analysis and thermal desorption spectroscopy.

Microstructure of a heavily irradiated metal exposed to a spectrum of atomic recoils

“…We find that vacancy concentration saturates well below the dose of 1 dpa, see Fig. 4 a, in agreement with independent simulations 13 , 14 , 16 and experimental observations 32 , 33 . This can be rationalised by recognising that the number of molten atoms per cascade is much higher than the number of ballistically displaced atoms, as suggested by their respective characteristic energy scales .…”

“…We compiled nuclear reaction analysis measurements of peak deuterium concentrations in tungsten irradiated to doses dpa under athermal conditions K for a broad range of irradiation energies from a number of studies 33 , 37 – 40 . For each particle energy represented in the experimental data, we simulated the recoil spectra, see Fig.…”

Microstructure of a heavily irradiated metal exposed to a spectrum of atomic recoils

“…We find that vacancy concentration saturates well below the dose of 1 dpa, see Fig. 4a, in agreement with independent simulations 13,14,16 and experimental observations 31,32 . This can be rationalised by recognising that the number of molten atoms per cascade is much higher than the number of ballistically displaced atoms, as suggested by their respective characteristic energy scales T d /E melt T d /E d .…”

“…First-principles simulations found that the deuterium binds preferentially to void surfaces, with a single tungsten vacancy trapping up to 5 deuterium atoms with trapping energies above 1.1 eV 41 . We compiled nuclear reaction analysis measurements of peak deuterium concentrations in tungsten irradiated to doses φ 0.3 dpa under athermal condition T < 500 K for a broad range of irradiation energies from a number of studies 32,[36][37][38][39] . For each particle energy represented in the experimental data, we simulated the recoil spectra, see Fig.…”

“…Although the experiments 32,[36][37][38][39] were conducted at temperatures below which vacancies become mobile, referred to as stage III recovery 42 , some lower-barrier interstitial migration processes may still contribute towards the interstitial-vacancy recombination. We do not expect this effect to play a significant role in tungsten, where interstitial migration barriers are so low that they are driven by the fluctuating stress fields present in the microstructure under irradiation.…”