An apparatus for beam-rocking reflection high-energy electron diffraction and total reflection angle x-ray spectroscopy

Characteristic x-ray emission from surface atoms induced by irradiation of an electron beam during reflection high energy electron diffraction (RHEED) depends on the incident glancing angle theta (g), since distribution of el ectron current density near surfaces depends on theta (g). Depth distributi on of elements, adatom height, and adatom site can be determined from theta (g) dependence of x-ray emission. This article describes an apparatus for measuring theta (g) dependence of x-ray emission during RHEED. X rays from the surface are sensitively detected at a grazing take-off angle theta (t) close to the critical angle for the total reflection. A small electron gun is rotated around the sample in ultrahigh vacuum to scan theta (g), during which the sample and x-ray detector are fixed. (C) 2001 American Institute of Physics.