New method for detection of Li inside He bubbles formed in B10-alloyed steel after neutron irradiation

Electron energy loss spectroscopy (EELS) was used to detect and study the spatial distribution on the nanoscale of He and Li in boron-alloyed steel after neutron irradiation. Li and He are the products of the 10B(n, α)7Li nuclear transmutation reaction and knowledge of their distribution is important to understand their influence on mechanical properties. Here, a new method is presented for the direct detection of Li in Fe, which is based on the analysis of the plasmon structure in EELS spectra. Li drops or particles in He bubbles show pronounced Li plasmon line at 10 eV which can be extracted from the Fe/Cr plasmon. The Gaussian or linear interpolation of the Fe/Cr plasmon and its subtraction allows for the calculation of Li and He two-dimensional maps and the study their spatial distribution. The analysis of Li plasmon fine structure allows imaging surface effects in the Li drops.

► New method for Li detection in Fe/Cr using plasmon EELS spectra.
► Spectroscopic 2D imaging of Li and He distribution inside individual bubbles in Fe/Cr.
► First detection of Li in 10B alloyed steels after neutron irradiation.