Abstract
X-ray phase contrast nanotomography enables imaging of a wide range of samples with high spatial resolution in 3D. Near-field holography, as one of the major phase contrast techniques, is often implemented using X-ray optics such as Kirkpatrick-Baez mirrors, waveguides and compound refractive lenses. However, these optics are often tailor-made for a specific beamline and challenging to implement and align. Here, we present a near-field holography setup based on Fresnel zone plates which is fast and easy to align and provides a smooth illumination and flat field. The imaging quality of different types of Fresnel zone plates is compared in terms of the flat-field quality, the achievable resolution and exposure efficiency i.e. the photons arriving at the detector. Overall, this setup is capable of imaging different types of samples at high spatial resolution of below 100 nm in 3D with access to the quantitative phase information.
Highlights
X-ray nanotomography is a powerful tool to image objects in three dimensions (3D) with high spatial resolution in materials science, biology as well as in medicine
We present a near-field holography setup based on Fresnel zone plates which is fast and easy to align and provides a smooth illumination and flat field
We showed that with off-axis illumination for near-field holography using a simple Fresnel zone plates (FZP) it is possible to obtain high quality 3D reconstructions of different sample types
Summary
X-ray nanotomography is a powerful tool to image objects in three dimensions (3D) with high spatial resolution in materials science, biology as well as in medicine. There are two major full-field tomography techniques in use, namely Zernike phase contrast [6,7] and near-field propagation based microscopy in a cone beam setting (near-field holography, NFH) [8]. NFH at the nano scale is usually performed using Kirkpatrick-Baez (KB) mirrors, conceivably combined with X-ray waveguides [9,10]. This technique does allow for nanotomography at high temporal resolutions [11]. For Zernike phase contrast, most commonly Fresnel zone plates (FZP) and beamshaping condensers are used [12,13,14,15]. In contrast to NFH, full-field Zernike phase contrast does usually not allow to retrieve the phase signal quantitatively
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