Planar PMMA X-ray compound refractive lenses with cascaded parabolic microstructures

Abstract X-ray compound refractive lenses (CRLs) have been successfully integrated into third- and fourth-generation synchrotron radiation sources. We have developed a new planar CRL architecture using cascaded parabolic microstructures constructed with polymethylmethacrylate. Two sets of CRL elements with different parabolic profile parameter values, radius of curvature R , and geometric aperture R 0 were integrated. One half of the set had a large geometric aperture ( R 1 = 100 μ m and R 01 = 141 μ m ), while the other half of the set had a small radius of curvature ( R 2 = 50 μ m and R 02 = 70 μ m ). The cascaded parabolic CRLs (CP-CRLs) were tested for hard X-ray microfocusing in the BL15U1 beamline at the Shanghai Synchrotron Radiation Facility. Experimental results showed that the developed CP-CRLs achieved two-dimensional focusing of the incident X-ray beams. The measured focal length was 0.341 m, and the transmission was 10.12%. The measured horizontal and vertical full width half maxima of the focused X-ray spot were 9 . 78 μ m and 9 . 70 μ m , respectively. Thus, the experimental results obtained in this work confirmed the theoretical calculations of CP-CRL microfocusing performance.