Investigation On The Nanofocusing Charateristics Of Refractive Lens For Hard X-ray

An X-ray refractive lens is an X-ray focusing and imaging device based on theprinciple of optical refraction, which consists of a plurality of single concave lenses withlarge radius of curvature or a single Kinoform lens with small radius of curvature.Employing micro-machining or semiconductor technology, the X-ray refractive lens isusually integrated on a substrate to form a simple and compact structure. Compared withX-ray reflection and diffraction focusing optics, X-ray refractive lenses have so manyadvantages, such as simple installation and commissioning, high roughness tolerance,focusing higher photon energy and so on. For these advantages, X-ray refractive lenseshave been widely used in synchrotron radiation facilities all over the world, becoming themain X-ray collimators and focusing optics. Moreover, with the urgent needs of X-rayanalysis techniques in the scientific studies on nanometer spatial resolution, it isbecoming very important that X-ray focusing optics focus X-ray to a very small spot sizewith high performance. X-ray refractive lenses have been applied in the transmissionfull-field X-ray nano-imaging and micro-beam scanning probe. In the future, X-rayrefractive lenses with optimized parameters could achieve sub-nanometer focal spot, hightransmittance and light intensity gain. Therefore, the X-ray refractive lens is expected to be the most important optics for high-energy hard X-ray nano-focusing.In this thesis, the focusing performance and design method of X-ray refractive lensare mainly studied. First of all, An X-ray refractive lens numerical simulation program isestablished. Secondly, a complex refractive lens is designed, which is capable of focusingX-ray to sub-nanometer dimension. Thirdly, to develop X-ray high efficiency focusingoptics, a single X-ray Kinoform lens is considered, and its focusing performance isstudied by numerical simulation methods. Finally, the idea of X-ray bending refractivelens and sheet refractive lens are come up with. The main contributions of this thesis aresummarized as follows:1.In order to verify the design and analyze the focusing performance, An X-rayrefractive lens numerical simulation program is established.2.Based on the simulation platform, it is the first time to successfully design alens which can focus hard X-ray to subnanometer dimension. The lens is comprisedof a series of Kinoform lenses, whose aperture is gradually matched to theconverging trace of the X-ray beam so as to increase the numerical aperture (NA).The simulation results show that the lens can achieve a lateral size of0.92nm(full-width at half-maximum (FWHM)) and an axial size of98nm (FWHM) withintensity gain of49050. In the future, it is expected to be applied in the hard X-rayscanning nano-imaging in near atomic resolution.3.The focusing performance of single Kinoform lens is studied. The results showthat a single Kinoform lens is optimized designed to focus30keV hard X-ray down toa lateral size of14nm (full-width at half-maximum (FWHM)), an axial size of62μm(FWHM) with intensity gain of four orders of magnitude and transmittance of30%. Itis an effective design for hard X-ray nanoprobe.