In order to clarify the poisoning mechanism of cathodes, the temperature dependence of oxidation on a single-crystal surface was examined using Auger electron spectroscopy. The oxidation had a chemical effect upon the La and B Auger peaks. Evidence from the Auger spectra indicated that oxygen was more strongly bound to La ions than B ions on the surface.

Auger Electron Spectroscopy Study of Oxidation on Lanthanum Hexaboride. Oshima, C., Kawai, S.: Applied Physics Letters, 1973, 23[5], 215-6