70 YEARS OF AUGER-SPECTROSCOPY, A HISTORICAL-PERSPECTIVE

The discovery of the nonradiative decay of an inner-shell ionized atom by the emission of an electron was made by P. Auger in 1925. The firs t investigation of Auger electrons by means of a magnetic electron spe ctrograph was done by Robinson and Cassie in 1926, this marks the birt h date of Auger spectroscopy. The following 70 years of Auger spectros copy of atoms will be divided into three periods. In the first period (1926-1960; Section 2) Anger spectroscopy was mainly connected with be ta-ray spectroscopy where inner-shell ionization in atoms in the solid state was caused either by gamma-conversion or by electron capture. I n the second period (beginning in 1960; Section 3) Auger spectroscopy developed independently of the availability of radioactive sources by using external excitation of gaseous atomic or metal vapor targets. Th e third period (beginning in 1977/78; Section 4) is characterized by t he use of synchrotron radiation with its outstanding properties of tun ability, polarization and narrow-band high-intensity for the excitatio n and ionization of inner-shell electrons. (C) 1998 Elsevier Science B .V. All rights reserved.