A quick convergent-beam laboratory X-ray reflectometer using a simultaneous multiple-angle dispersive geometry

An X-ray reflectometer using a laboratory X-ray source for quick measurements of the specular X-ray reflectivity curve is presented. It uses a bent-twisted crystal to monochromatize and focus the diverging X-rays (Cu Kα₁) from a laboratory point source onto the sample. The reflected X-rays are recorded with a two-dimensional detector. Reflectivity curves can be measured without rotating the sample, detector or X-ray source during measurements. The instrument can separate the specularly reflected X-rays from the diffuse scattering background, so low reflectivities can be measured accurately. For a gold thin film on silicon, the reflectivity down to the order of 10^-6 was obtained with a measurement time of 100 s and that down to 10^-5 with a measurement time of 10 s. Reflectivity curves of a silicon wafer and a liquid ethylene glycol surface are shown as well. Time-resolved measurements of a TiO₂ surface during UV irradiation are also reported.