LIGA fabrication of X-ray Nickel lenses

Abstract

Nickel refractive planar lenses generating line and point X-ray spots were fabricated by LIGA technology. The optimum parameters of the lenses were simulated for a kinoform lens profile and an X-ray energy range from 100 keV to 1 MeV. The focusing elements of the lens are characterised by an aspect ratio of about 200 and a side-wall roughness of less than 5 nm r.m.s. The optical characteristics of the lenses were tested at the ESRF using a photon energy of 212 keV. A focal spot of 10 μm size was measured using a X-ray sensitive film as a width at a half maximum of the darkening of this detector. A ratio of appr. 7 of the detector responses of the focused spot to the unfocused radiation was measured. The correspondent characteristics of the focal spot of the lens for the revealed photon flux are FWHM = 6 μm and ~20 for the gain.