The soft x-ray absorption spectra of Be and BeO were measured near the <i>K</i> edge using the NBS 180 MeV synchrotron as a background continuum source. The energy-loss spectrum of 20-keV electrons transmitted through thin Be films at zero scattering angle was measured in the corresponding 100-170 eV energy-loss range. The <i>K</i> edges of Be and BeO measured by x-ray absorption were at 112.1±0.2 eV and 118.4±0.2 eV, respectively. The Be <i>K</i> edge in the electron-energy-loss spectrum was at 111.7±0.4 eV. The positions of maxima in the absorption fine structure determined by the two techniques were also in good agreement.
N. SWANSON and K. CODLING, "Excitation of K-Shell Electrons in Be by Soft X Rays and 20-keV Electrons," J. Opt. Soc. Am. 58, 1192-1194 (1968)