Elastic and inelastic contributions to the angular intensity anisotropy of electron emission

The relative importance of the contribution of elastic and inelastic electrons to the 2p core-level ionization yield has been evaluated as a function of both depth and electron energy. We measured the intensity of the 2p ionization loss of a thin Co film buried in an Fe matrix, as a function of the incidence angle of the primary beam, for increasing depth and for different values of the primary beam energy. The emission intensity anisotropy directly reflects the intensity anisotropy of the elastic primary electrons at the depth where the Co marker is located, as it results from the focusing and defocusing of primary electron wave intensity along low index Fe atomic chains. The in-depth anisotropy profile we measured has been compared with the intensity anisotropy of the Co LMM Auger signal, which contains a contribution from inelastic (isotropic) primary electrons. The contribution of inelastic electrons to the ionization has been found to be larger at the surface and at higher electron energy. (C) 1998 Elsevier Science B.V.