Inner-Shell Excitation by Channeled Electrons

摘要

An interesting situation occurs when inner shell electrons in crystalline materials are excited by electron beams of kilovolt energies in a transmission electron microscope. For many years the subsequent x-ray emission has been used as the basis of an analytical technique, giving compositional information at high spatial resolution. Recently this technique has been extended to provide information on impurity lattice site location, the basis of the technique being to take two fluorescence spectra, one under channeling conditions and one ''random'' spectrum with the crystal oriented away from strongly channeling planes or axes. Since electrons channel along the positive potential wells of the atomic planes or strings, a higher yield of characteristic x-ray emission is expected from the channeled case, for the same incident beam current. This channeling effect can be defined as the relative increase in x-ray yield. This paper discusses using channeled electron to excited inner-shell electrons. 4 refs., 3 figs. (ERA citation 14:021335)