The sensitivity of NRA for deuterium quantification in Li-based materials

• Retained amounts of 2 H in fusion materials are commonly quantified via NRA by using incident 3 He + ion beams. • Competing nuclear reactions yields are observed in the NRA spectra collected from Li-based materials. • 2 H quantification hampered by the superposition of both 2 H( 3 He,p 0 ) 4 He and 6 Li( 3 He,p 1 ) 8 Be yields. • For all the Li materials, it is possible to achieve experimental conditions imposing detection limits significantly lower than 1 × 10 16 2 H/cm 2 . The use of lithium (Li) and Li-based materials for liquid metal applications is a promising solution to protect solid plasma facing materials from dense power flows in operative fusion scenarios. The recovery of the liquid materials and the affinity of lithium to retain hydrogen motivates an extensive research of the retained deuterium amounts, which is commonly investigated by Nuclear Reaction Analysis (NRA) by resolving the 2 H( 3 He,p) 4 He reaction yields. Nevertheless, the incidence of 3 He ion beams induces other competing nuclear reactions such as 6 Li( 3 He,p i ) 8 Be, 7 Li( 3 He,p i ) 9 Be and 7 Li( 3 He,d i ) 8 Be, with related particle yields visible in the spectra. Particularly, the energy width of the p 1 emission of the 6 Li( 3 He,p i ) 8 Be reaction is large (about 1.75 MeV), and the 6 Li( 3 He,p i ) 8 Be yield becomes superimposed to the 2 H( 3 He,p 0 ) 4 He one. Even so, deuterium quantification is possible to achieve due to the cross-sections of both proton emissions, being the detection limits widely dependent of the Li contents, of the energy of the incident 3 He ion beam and of the energy resolution of detection system. In the present experiment, Li-Sn alloys were used as Li-based material. The case of pure Li was extrapolated from the experimental data. For a standard analysis with accumulated charges of 5 μC in the collected spectra, minimum detectable amounts within the range from ∼1 × 10 15 at./cm 2 to ∼1 × 10 16 at./cm 2 were predicted for all the studied examples.