Development of X-ray polarization microscopy

The purpose of this study is to develop x-ray polarization microscopy which enables us to observeimages of polarization contrast due to linear dichroism (LD) and circular dichroism (CD) in x-rayspectral range. This method can be applied to the anisotropy of materials in x-rayenergy range. This study consists of (1) Development of high resolution CCD x-ray检测器，Observation of x-ray images of polarization contrast due to x-ray linear dichroism (XLD)，and (3) Observation of x-ray images of polarization contrast due to x-ray magnetic circulardichroism (XMCD)(1) The critical element of The high resolution CCD x-ray detector is a phosphorscreen to convert x-rays to visible light. conversion efficiencynon-uniformity of反应和spatial resolution of the phosphor have been optimized by choosingphosphor materials, thicknesses, deposition methods, substrate materials. As a resultD22 D2S:Tb(P-43) with a 10 micron thickness has been chosen. When the CCD x-raydetector with this phosphor is combined with an x-ray magnifier made of Si 111 asymmetric crystal，this imaging system has shown a spatial resolution of 1.2 micron.(2) Images of polarization contrastdue to x-ray linear dichroism (XLD) has been successfully observed with cobalt single crystal atK-edge (7709 eV).这是fist time that the polarization-contrast image due to XLD is observed inhard x-ray range.(3) Images of polarization contrast due to x-ray magnetic circular dichroismhas been successfully observed with cobalt polycrystals at K-edge （7709 eV）。

The purpose of this study is to develop an x-ray polarization microscopy which enables us to observe images of polarization contrast due to linear dichroism (LD) and circular dichroism (CD) in x-ray spectral range. This method can be applied to the observation of anisotropy of materials in x-ray energy range. This study consists of (1) Development of high resolution CCD x-ray detector, (2) Observation of x-ray images of polarization contrast due to x-ray linear dichroism (XLD), and (3) Observation of x-ray images of polarization contrast due to x-ray magnetic circular dichroism (XMCD)(1) The critical element of the high resolution CCD x-ray detector is a phosphor screen to convert x-rays to visible light. The conversion efficiency, non-uniformity of response and spatial resolution of the phosphor have been optimized by choosing phosphor materials, thicknesses, deposition methods, substrate materials. As a result, GdィイD22ィエD2OィイD22ィエD2S:Tb(P-43) with a 10 micron thickness has been chosen. When the CCD x-ray detector with this phosphor is combined with an x-ray magnifier made of Si 111 asymmetric crystal, this imaging system has shown a spatial resolution of 1.2 micron.(2) Images of polarization contrast due to x-ray linear dichroism (XLD) has been successfully observed with cobalt single crystal at K-edge (7709 eV). It is the fist time that the polarization-contrast image due to XLD is observed in hard x-ray range.(3) Images of polarization contrast due to x-ray magnetic circular dichroism (XMCD) has been successfully observed with cobalt poly-crystals at K-edge (7709 eV).