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We developed a micron-CT consisting of micro-beam system and X-ray CCD camera (Hamamatsu photonics C8800X), whose element size is 8μm×8μm and a total number of image elements 1000×1000 gives an image size of 8mm×8mm. The sample is placed in a tube of a small diameter, which is rotated by a stepping motor. The transmission data through the sample are taken with characteristic Ti-K-X-rays (4.558 keV) produced by 3MeV proton and α particle micro-beams. After image reconstruction using an iteration method, 3D-images of small objects namely, hair and small ants were obtained with a spatial resolution of ~5μm. It is expected that our micron-CT can provide cross sectional images of in-vivo cellular samples with high resolution and can be applied to a wide range of research in biology and medicine.

We have developed “micron-CT”, using micro-PIXE for in-vivo imaging. This system comprises an X-ray CCD camera (Hamamatsu photonics C8800X9) with high resolution (pixel size: 8×8μm², number of pixels: 1000×1000) and an X-ray-point-source with a spot size of 1.5×1.5μm² which is generated by irradiation of a microbeam on a pure metal target. Thus we can acquire projection data with high resolution. The sample is placed in a small diameter tube and is rotated by a stepping motor. The 3D images were reconstructed from the obtained projection data by using cone-beam CT reconstruction algorithm. X-ray spectra produced by heavy charged particle bombardment, exhibit a much smaller continuous background compared to electron bombardment. Therefore, X-rays produced by ion beam can be used as a monochromatic and low energy X-ray source. The feature is very effective to investigate small insects. Moreover we can get elemental distribution image of object by choosing appropriate characteristic X-rays corresponding to the absorption edge. On the other hand, the conventional X-ray CT, in which continuous X-rays are used, provides images of the electron density in the object. Using this system, we were able to get 3D images of a living ant's head with 6 μm spatial resolution. By using Fe-K-X-rays (6.40 keV) and Co-K-X-rays (6.93 keV), we can investigate the 3D distribution of Mn (K-absorption edge = 6.54 keV) in an ant's head.

We are developing a µ-CT (micro computed tomography) which enables to observe the interior of living small insects. In this study, we applied the µ-CT to get CT images of the egg of drosophila, since the drosophila is applied to various basic studies, such as gene research. The interior of the living egg was observed and it was uniform. In the case of the dried egg, the shell and the interior structure were confirmed. This result comes from the growth of the living egg.

In this paper, we have developed a wavelength dispersive X-ray spectrometer microparticle-induced X-ray emission (WDX-$\mu$-PIXE) system combining a microbeam system with high spatial resolution and wavelength dispersive X-ray (WDX) spectrometry with high-energy resolution for chemical state mapping. A Von Hamos geometry was used for the WDX system to achieve higher detection efficiency and energy resolution. The system consists of a curved crystal and a CCD camera. The WDX system was installed in a newly developed microbeam system. The energy resolution of the WDX system was 0.67 eV for $\text{Si-}{K}_{\alpha 1}$ (1740 eV). $\text{Si-}{K}_{\alpha 1,2}$ and $\text{Si-}{K}_{\beta }$ X-ray spectra from various Si compounds were measured and chemical shifts related to chemical states were clearly observed. The system was applied to the chemical state analysis of clay particles. After elemental mapping of the clay particles using a conventional $\mu$-PIXE system with a Si(Li) detector, particles to be analyzed were selected and analyzed sequentially with the WDX system. $\text{Si-}{K}_{\beta }$ spectra from clay particles were obtained. The microscopic spatial distribution of elements and chemical state of the clay particles were sequentially measured with high energy and spatial resolution using a microbeam.