High spatial resolution microanalysis in scanning transmission electron microscopes is most easily performed when the specimen is inside a magnetic immersion objective lens. Recently a technique has been developed to perform spectroscopy of electrons that originate in this magnetic field. A very special form of photo electron spectroscopy is then possible for thin specimens in the microscope. An energy loss ΔE of a primary electron has the same physical effect as the absorption of a photon of energy ΔE. A coincidence measurement between energy loss electrons and the emitted electrons is expected to give a so called coincidence electron spectrum, or (e,2e) spectrum, of a very small area, which gives the same physical information as photo electron spectroscopy. Normal photo electron spectroscopy of limited spatial resolution, but with high collection efficiency, should also be possible in a scanning transmission electron microscope if the specimen is illuminated with a photon beam. Experiments to test the expectations are in progress.
Pijper, F. J.; Bleeker, A. J.; Endert, R. J.; and Kruit, P.
"Prospects for Photo Electron Spectroscopy in a Scanning Transmission Electron Microscope,"
Scanning Microscopy: Vol. 3
, Article 8.
Available at: https://digitalcommons.usu.edu/microscopy/vol3/iss1/8