• Electron Energy Loss Spectroscopy (EELS)
• Core Electron Energy Loss Spectroscopy (CEELS)
• High Resolution Electron Energy Loss Spectroscopy (HREELS)

EELS uses electrons from 0.1 to 10 keV and passes them through a thin foil of the material of interest. At high energies, the transmitted beam contains inelastically scattered electrons whose energy has been decreased by amounts corresponding to characteristic absorption frequencies in the solid. At lower energies, the reflected beam is monitored for the same transitions. Bulk and surface plasmons are the principal features of these spectra.
CEELS needs electrons of energy sufficient to ionize core electrons. Usually studied in the double differential mode (like AES). Signals are characteristic of atomic core energy levels. EELS and CEELS are less common. So here we just give brief description of them, and we give a more comprehesive description of HREEELS.
HREELS is the most important electron loss spectroscopy. A new variant, TREELS (Time-Resolved Electron Energy Loss Spectroscopy - the "high resolution" is still inferred) allows one to monitor these signals in real time to study kinetic events.