3-D Imaging Tomography with Sub-micrometer Resolution Using Fresnel Zone Plate Optics

X-ray microtomography has been developed for use in various fields such as biology, materials science, petrology, and medical diagnosis. This method’s setup commonly consists of a simple projection geometry with a high-resolution imaging detector and a highly collimated beam, e .g . , a microfocussing X-ray tube or synchrotron radiation source, which can result in a spatial resolution of about 1 μm [1]. Achieving a higher resolution with this method, however, is difficult for two reasons: one is the image blurr ing caused by beam deflection (both refraction and diffraction), and the other is the limited spatial resolution of the imaging detector (~ 1 μm). One promising way to overcome those problems is combining X-ray imaging microscope optics using an X-ray imaging device as an objective – so called “imaging microtomography.” Various types of X-ray imaging dev ices whose theoret ica l spat ia l resolutions are in order of 10 100 nm have now been developed, and almost all of them have already attained the sub-micrometer resolution; even 100-nm-resolution has been achieved with some of them [2]. Since the imaging microscope setup enables magnification of the X-ray image,