Reduced deuterium retention in simultaneously damaged and annealed tungsten

Simmonds, M.; Wang, Y.Q.; Barton, J.L.; Baldwin, M.J.; Yu, J. H.; Doerner, R. P.; Tynan, G. R.

doi:10.1016/j.jnucmat.2017.06.010

Cited by 28 publications

(21 citation statements)

References 23 publications

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“…) − 𝐸 𝑑𝑖𝑓𝑓 𝑣𝑎𝑐 = 0.85 eV (6) This binding energy, according to equation ( 4) corresponds to a vacancy cluster of size n = 5.8. Of course sizes of vacancy clusters are integers, but this calculated size just means that the majority of cluster dissociation that explains our drop in small vacancy cluster annealing at 800 K should be mainly due to dissociation of cluster with sizes 6 and a smaller contribution by dissociation of clusters with 5 captured vacancies.…”

Section: Defect Type Iismall Vacancy Clustersmentioning

confidence: 99%

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Effect of D on the evolution of radiation damage in W during high temperature annealing

et al. 2020

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The effect of deuterium (D) on the annealing of radiation damage was studied. Tungsten (W) samples were sequentially irradiated with 20 MeV W ions at room temperature and loaded with a low-temperature D plasma at 370 K to decorate the created defects. After this, half of each sample was W irradiated at room temperature again to create additional radiation damage. To study the evolution of the created defects with D being present, samples were annealed by heating them to a desired temperature and held for two hours. The surviving displacement damage was decorated by re-exposing the samples to the same D plasma as before. At various steps of the experiment the D depth profiles were measured using Nuclear Reaction Analysis and after the last re-exposure a Thermal Desorption Spectroscopy analysis was done to determine the D desorption spectra.D release is dominated by two desorption peaks centered at 520 K and 780 K for a 3 K/min temperature ramp. For temperature holds below 500 K no measurable change in the intensity of the desorption peaks was measured. For temperature holds above 500 K, the low temperature D desorption peak started to reduce in intensity. The high temperature D desorption peak showed signs of evolution only for temperature holds above 600 K. This behaviour was independent of the number of W irradiations used.A macroscopic rate equation model was used to recreate the experimental results. Using the fill-level dependant D-defect interaction picture we were able to determine that three distinct defect types with several fill-levels each are sufficient to describe the results. The concentrations of defect 1 (vacancies) and defect 2 (small vacancy clusters) reduced by 50 % and 35 %, respectively, after an 800 K temperature hold. No reduction was found for defect 3 (large vacancy clusters).

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Section: Defect Type Iismall Vacancy Clustersmentioning

confidence: 99%

“…It is clear that in order to fully understand the influence of displacement damage on HI retention, one must understand the evolution of defects at elevated temperatures. In the recent past, several studies were conducted to address this in detail [4][5][6]. However, in all these cases the annealing of displacement damage in hydrogen-free tungsten was studied.…”

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confidence: 99%

Effect of D on the evolution of radiation damage in W during high temperature annealing

et al. 2020

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“…However, as HD contributed only an average of 28% to the total D flux this is of minor importance. As described previously [17], variable ambient laboratory humidity, temperature, and length of vacuum break influence the water content adsorbed to the TDS chamber walls. This leads to a significant H 2 background signal that was scaled to and subtracted from the raw HD and D 2 signals.…”

Section: Final Tdsmentioning

confidence: 95%

“…Contaminants from polishing were removed in successive ultrasonic baths of acetone followed by ethanol. Next, the samples were annealed at 1173 K for 1 hour in a vacuum chamber below 10 −4 Pa. As noted in [17], a broken W sample displayed elongated grains perpendicular to the surface with dimension on the order of 10 µm parallel to the surface, as viewed by a scanning electron microscope. The maximum annealing temperature is well below the recrystallization temperature, leaving an intrinsic level of various defects throughout the bulk of the sample.…”

Section: Sample Preparationmentioning

confidence: 96%

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Isolating the detrapping of deuterium in heavy ion damaged tungsten via partial thermal desorption

Simmonds

Schwarz-Selinger

et al. 2019

Journal of Nuclear Materials

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Partial Thermal Desorption Spectrometry (pTDS) progressively depopulated trapped deuterium (D) from heavy-ion damaged tungsten (W) to determine spatial location and detrapping energies. W samples were prepared identically: 5 MeV Cu 2+ damaging ions (0.12 peak dpa dose) before D 2 plasma loading (10 24 D/m 2 fluence) held at 373 K. Each sample reached one of six pTDS peak-and-hold temperatures. Nuclear Reaction Analysis (NRA) measured the D spatial profile remaining after pTDS, before final TDS. NRA and TDS measured total D retention were in good agreement. NRA displayed three zones of D-populated defects: (I) near-surface (below 0.1 µm), (II) heavy-ion damage (peaked ∼1 µm), and (III) uniform intrinsic (bulk). D concentration in zone I reduced by ∼ 97% in samples with pTDS at 597 K and higher, indicating near-surface traps have low detrapping energy. The Stopping and Range of Ions in Matter (SRIM) predicts a displacement profile

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