title: Grazing exit electron probe microanalysis for surface and particle analysis.
abstract: We developed a new method of grazing exit electron probe microanalysis (GE-EPMA) and applied it to analyze both Si surfaces and Mg-salt particles. In conventional EPMA, X-rays are detected at an exit (takeoff) angle of approximately 45°. Therefore, when particles collected on a sample carrier are analyzed by EPMA, the X-rays from both the particles and the carrier are detected, although we need only the X-rays emitted from the particle itself. In contrast to this, the X-rays are detected at grazing exit angles in GE-EPMA. The X-rays emitted from deep inside of the sample are not detected under grazing exit conditions, and only X-rays emitted from the surface and the particle are measured. It was found that surface-sensitive analysis of a Si wafer was possible with low background at grazing exit angles. The intensity ratio of O Kα to Si Kα increased near zero degrees, indicating that the Si wafer is covered with a native Si oxide. Moreover, Mg Kα X-rays from a Mg-salt particle, which was deposited on the Si wafer, were detected with a small Si Kα intensity at grazing exit angles of less than 0.5°. By decreasing the exit angle to less than zero, only the top of the particle was observed; therefore, GE-EPMA measurement would make it possible to investigate the surface layer of one particle.
authors.affiliation: Micro- and Trace Analysis Center, Department of Chemistry, University of Antwerp (UIA), B-2610 Antwerpen, Belgium, and Institute for Materials Research, Tohoku University, Katahira-2-1-1, Aoba, Sendai, 980-8577 Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tsuji
authors.forename: K
authors.initials: K
authors.lastname: Wagatsuma
authors.forename: R
authors.initials: R
authors.lastname: Nullens
authors.forename: R E
authors.initials: RE
authors.lastname: Van Grieken