Article

A LABORATORY ReflEXAFS SPECTROMETER

Le Journal de Physique Colloques 12/1986; 47(C-8). DOI: 10.1051/jphyscol:1986820

ABSTRACT Nous présentons un spectromètre simple, spécialement construit pour les mesures de ReflEXAFS. Il utilise un tube de rayons-X conventionnel associé à un miroir parabolique. Un monochromateur à deux cristaux (LiF) permet d'obtenir une résolution de 8,5 eV à 8 keV. Le faisceau incident est monitoré par un compteur proportionnel et le faisceau réfléchi est mesuré par un compteur à scintillation (NaI) qui permet d'éliminer les harmoniques par discrimination d'énergie. Le spectromètre est utilisable de 7 à 18 keV. Les spectres relatifs à la surface d'un échantillon de nickel avant et après oxydation thermique sont présentés. A simple spectrometer using a conventional X-ray generator has been constructed for ReflEXAFS measurements at glancing angle. The X-ray source is a sealed X-ray tube with a parabolic mirror. A monochromator with two flat LiF crystals is used. The energy resolution amounts to 8.5 eV at 8 keV. A proportional counter monitors the incident X-ray intensity and a NaI scintillation detector measures the intensity of the reflected beam. This system is free from fluctuations of the incident X-ray intensity and harmonics can be rejected with the energy discrimination. The range of energy is 7 to 18 keV. The ReflEXAFS spectra related to the surface of a nickel sample and a thermally oxided nickel sample are presented.

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