Description:
<jats:p>A new high-energy (500 keV) electron–electron coincidence apparatus is described making possible for the first time triply differential cross-section measurements of inner-shell ionization of atoms of a high atomic number. Moreover, the apparatus has also been designed to deliver doubly differential ionization cross sections of the individual shells by using electron–x-ray coincidences as well as noncoincident low background spectra of inelastically scattered electrons. A special feature of the apparatus is the use of electron spectrum analyzers consisting of a nondispersive magnet and a surface barrier detector. Magnetic electron spectrum analyzers consisting of a sector field magnet and a scintillation detector have been built up. Selected measurements on tantalum (Z=73), silver (Z=47), and aluminum (Z=13) target foils are presented.</jats:p>