Ion beam analysis of Li-Sn alloys for fusion applications

Mateus, R.; Costa, Miguel; Alves, L.C.; Catarino, N.; Silva, R.C. da; Dias, M.; Guedes, M.; Ferro, A.C.; Alves, E.

doi:10.1016/j.nimb.2020.09.019

Cited by 1 publication

(1 citation statement)

References 27 publications

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“…However, both require an experimentally obtained cross-section and such cross-sections are not always available. The EBS cross-section for H-Li has been recently measured at a similar angle as in our setup, [21], and it is widely used [22][23][24]. A drawback for EBS however is that, due to the low mass number of deuterium, the backscattered protons have low energy.…”

Section: Ebs Analysis and Nra Analysismentioning

confidence: 95%

Deuterium retention in co-deposition with lithium in Magnum-PSI: experimental analysis and comparison with SOLPS-ITER

Morbey,

Gonzalez,

Arnoldbik

et al. 2024

Nucl. Fusion

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The vapor-box is a liquid metal based design to cope with the demanding conditions of the divertor. This design relies on the recirculation of lithium by evaporation and condensation. An issue to this approach is the safety risks of Li-D/T formation and co-deposition on both the vapor-box walls - leading to possible recirculation impedance- and on the first wall leading to unacceptable tritium retention. Additively manufactured tungsten Capillary Porous Structure (CPS) samples filled with Li were exposed to high heat flux D plasmas in the linear plasma device Magnum-PSI and Li-D co-deposition was measured as a function of substrate temperature, estimated to be in the range 200-428 ${^\circ}$C and distance between 25-85 mm to the plasma beam center. The D:Li ratio was determined via in-situ ion beam diagnostics (NRA and EBS) and the spectra analyzed simultaneously to maximise the precision of the measurement. The experimental results approach close to the theoretical maximum at 40:60 D:Li ratio and the thickness of the deposited films was 0.02 - 3.2 $\mu$m. For witness plate temperatures above 400 ${^\circ}$C Li films under 150 nm in thickness were deposited and show lower D:Li ratios, as low as 5:95 D:Li ratio. At these temperatures the evaporation rate from the WPs is close to the deposition rate, and the decomposition pressure for LiD becomes comparable to the operational pressure in the vessel during the discharge. SOLPS-ITER simulations were also conducted to complement the experimental data. The results were used to narrow the range of CPS surface temperature to between $650-700$^{\circ}$C and determined that the D$^{+}$ plasma is largely replaced by Li$^{+}$ plasma close to the target surface. Further, the redeposition ratio of the lithium on the CPS surface is determined to be around 80$\%$, which matches well with the value determined from a quartz crystal microbalance. Due to limitations in the modeling of neutral interactions with Li coated surfaces, the SOLPS-ITER modeling does not well recreate the observed Li and D deposition layers on the WPs, indicating that this aspect of the modeling in Eirene needs improvement to accurately model plasmas containing significant quantities of Li. However, SOLPS-ITER simulations should be extended to include LiD molecules and improve the accuracy of heat flux towards the target to improve the comparison with experimental data.

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