Large-aperture prism-array lens for high-energy X-ray focusing

A new prism-array lens for high-energy X-ray focusing has been constructed using an array of different prisms obtained from different parabolic structures by removal of passive parts of material leading to a multiple of 2 π phase variation. Under the thin-lens approximation the phase changes caused by this lens for a plane wave are exactly the same as those caused by a parabolic lens without any additional corrections when they have the same focal length, which will provide good focusing; at the same time, the total transmission and effective aperture of this lens are both larger than those of a compound kinoform lens with the same focal length, geometrical aperture and feature size. This geometry can have a large aperture that is not limited by the feature size of the lens. Prototype nickel lenses with an aperture of 1.77   mm and focal length of 3   m were fabricated by LIGA technology, and were tested using CCD camera and knife-edge scan method at the X-ray Imaging and Biomedical Application Beamline BL13W1 at Shanghai Synchrotron Radiation Facility, and provided a focal width of 7.7   µ m and a photon flux gain of 14 at an X-ray energy of 50   keV.

Source: Journal of Synchrotron Radiation - August 3, 2016 Category: Physics Authors: Zhang, W. Liu, J. Chang, G. Shi, Z. Li, M. Ren, Y. Zhang, X. Yi, F. Liu, P. Sheng, W. Tags: X-ray optics refractive lenses prism-array lenses LIGA technology knife-scan method research papers Source Type: research