High Loss

Energy loss > 100eV

For the ionization of atoms, a specific minimum energy, the critical ionization energy EC or ionization threshold, must be transferred from the incident electron to the expelled inner-shell electron, which leads to ionization edges in the spectrum at energy losses that are characteristic for an element. Thus, EELS is complementary to X-ray spectroscopy, and it can be utilized for qualitative and quantitative element analysis as well. In particular, the detection of light elements is a main task of EELS. Compared to the plasmon generation, the inner-shell ionization is a much less probable process, leading to a low intensity of the peaks. In the high-loss region, the amount of inelastically scattered electrons drastically decreases with increasing energy loss, thus small peaks are superimposed on a strongly decreasing background (s. spectrum). Because of the low intensity, the representation of the high-loss region is often strongly enhanced (here: intensity gap at about 220 eV).