Ultrahigh-Vacuum Facility for High-Resolution Grazing-Angle X-ray Diffraction at a Vertical Wiggler Source of Synchrotron Radiation

Abstract

A versatile ultrahigh-vacuum chamber has been designed for grazing-angle X-ray standing-wave and diffraction experiments at the vertical wiggler source of the Photon Factory. Unlike at other sources, the vertically polarized X-rays from the wiggler favour the use of a horizontal scattering geometry. The X-ray chamber is equipped with a hemispherical beryllium window, which allows any scattering angle to be attained and secondary emissions to be measured. The chamber is of a compact design, sitting on a precision rotary table which is rotated for scans. Samples are introduced from a portable vessel. The whole procedure can be performed in a vacuum better than 10 À7 Pa. The system has successfully been applied to a grazing-angle X-ray standing-wave experiment, which determined the dimer bond length and the domain structure of Si(001) surfaces deposited with monolayer arsenic.

Ultrahigh vacuum/high-pressure flow reactor for surface x-ray diffraction and grazing incidence small angle x-ray scattering studies close to conditions for industrial catalysis

“…In the latter geometry, the small volume around the sample is fully separated from the UHV in the remainder of the system, which consists of the compressed bellow and the sample preparation tools. The upper part of this small reactor volume is defined by a beryllium dome [25][26][27] with good transparency for the x-rays. The reactor walls ͑top flange and dome͒ are actively cooled by a water flow through the top flange as shown in Fig.…”