The design of a near backscattering detection device for surface morphology of spherically bent crystal analyzer

Abstract

Spherically Bent Crystal Analyzers (SBCAs) are the core optical components of x-ray spectrometers. They have been widely used in many x-ray spectroscopy end-stations at synchrotron radiation and x-ray free electron laser facilities around the world. Owing to the monochromatic and focal properties of SBCAs, x-ray spectrometers with high efficiency and high energy resolution can be well applied to the study of x-ray absorption spectroscopy (XAS) and emission spectroscopy (XES). Hence, the quality of SBCAs is the key factor in determining the performance of x-ray spectrometers. Previously, we have investigated the focal properties of Si(444) SBCAs by using a laboratory’s Rowland circle device. However, the original device is limited by movement distance of motors and the space between detector and x-ray source. It is only applicable to SBCAs with a radius of curvature of 500 mm, and the maximum Bragg angle is 86°. Here, we present a new simple near backscattering detection device, which is based on a long linear guideway, to inspect the surface morphology, crystal face morphology, and focal performance of SBCAs at Bragg angle of 88°. By simply adjusting the distance between the source, SBCAs, and detector, focal performance at the focal point can be detected, while crystal face can be imaged off the focal point. By switching the x-ray source to the LED light source, surface morphology is able to be imaged as well. Furthermore, SBCAs with different radius of curvatures within 1000 mm are all measurable by this new device.