Electron excitation: electron energy loss spectroscopy (ELS), core electron energy loss spectroscopy (CEELS), and high resolution electron energy loss spectroscopy (HREELS)

Abstract In none of these loss spectroscopies is spatial resolution required, but they do require electron sources capable of variable primary energy down to very low energies, with good stability. The need in HREELS for careful screening of the whole analytical system of source and analyser from strong magnetic fields has already been emphasized, as has the practice of minimizing currents of unwanted secondary electrons by coating internal surfaces with a low secondary emitter such as carbon.