Towards high-flux X-ray beam compressing channel-cut monochromators

The issue of a high‐flux X‐ray beam compressing channel‐cut monochromator for applications in X‐ray metrology is addressed. A Ge(111) compressor with compression ratio 20.3 was designed on the principle of a combination of symmetric and highly asymmetric diffractions. A pilot application of the single‐point diamond technology (SPDT) to finish active surfaces of X‐ray optics was tested, providing 50% flux enhancement as compared to a Ge(220) counterpart prepared by traditional surface treatment. This is much more than the theoretical 22% forecast and shows the potential of SPDT for preparation of high‐flux X‐ray compressors with a high compression ratio, where highly asymmetric diffraction with a very low exit angle is inevitable. The implications for efficient collection of X‐rays from microfocus X‐ray sources are discussed. A comparison of Ge compressors with Ge parallel channel‐cut monochromators combined with a 50 µm slit shows the several times higher flux of the former, making them applicable in X‐ray diffraction experiments at medium resolution. Furthermore, the Ge(111) compressor was tested as a collimator in high‐resolution grazing‐incidence small‐angle X‐ray scattering (GISAXS) measurements of surface gratings, providing experimental resolution close to 400 nm. This is ∼100 nm smaller than that achieved with the Ge(220) compressor but still approximately twice that of commercial SAXS/GISAXS laboratory setups. A high‐flux Ge(111) X‐ray beam compressing channel‐cut monochromator with high compression ratio based on a strongly asymmetric diffraction was designed and successfully realized by a pilot application of the single‐point diamond technology. Comparative testing demonstrates the potential of the new design and related technology, with direct implications for high‐throughput X‐ray laboratory setups, in particular those with microfocus X‐ray sources.