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

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 R0 were integrated. One half of the set had a large geometric aperture (R1=100μm and R01=141μm), while the other half of the set had a small radius of curvature (R2=50μm and R02=70μm). 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 9.78μm and 9.70μm, respectively. Thus, the experimental results obtained in this work confirmed the theoretical calculations of CP-CRL microfocusing performance.