ABSTRACT
We present an improved, single-distance phase retrieval algorithm applicable for holographic X-ray imaging of biological objects for an in-line germanium Bragg Magnifier Microscope (BMM). The proposed algorithm takes advantage of a modified shrink-wrap algorithm for phase objects, robust unwrapping algorithm as well as other reasonable constraints applied to the wavefield at the object and the detector plane. The performance of the algorithm is analyzed on phantom objects and the results are shown and discussed. We demonstrated the suitability of the algorithm for the phase retrieval on a more complex biological specimen Tardigrade, where we achieved successful phase retrieval from only a single hologram. The spatial resolution obtained by Fourier spectral power method for biological objects is â¼ 300 nm, the same value as obtained from the reconstructed test pattern. Our results achieved using the new algorithm confirmed the potential of BMM for in-vivo, dose-efficient single-shot imaging of biological objects.
ABSTRACT
The performance of a recently developed full-field X-ray micro-imaging system based on an in-line Bragg magnifier is reported. The system is composed of quasi-channel-cut crystals in combination with a Medipix single-photon-counting detector. A theoretical and experimental study of the imaging performance of the crystals-detector combination and a comparison with a standard indirect detector typically used in high-resolution X-ray imaging schemes are reported. The spatial resolution attained by our system is about 0.75â µm, limited only by the current magnification. Compared with an indirect detector system, this system features a better efficiency, signal-to-noise ratio and spatial resolution. The optimal working resolution range of this system is between â¼0.4â µm and 1â µm, filling the gap between transmission X-ray microscopes and indirect detectors. Applications for coherent full-field imaging of weakly absorbing samples are shown and discussed.
