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Development of X-ray polarization microscopy

X射线偏振显微镜的发展

基本信息

批准号：
09555019
负责人：
AMEMIYA Yoshiyuki
金额：
$ 8.64万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

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).

本研究的目的是开发一种X射线偏振显微镜，使我们能够观察由于线性二色性（LD）和圆二色性（CD）在X射线光谱范围内的偏振对比度的图像。该方法可用于X射线能区材料各向异性的观测。本研究包括（1）高分辨率CCD X射线探测器的研制，（2）X射线线性二向色性（XLD）偏振衬度X射线图像的观测，（3）X射线磁圆二向色性（XMCD）偏振衬度X射线图像的观测。（1）高分辨率CCD X射线探测器的关键元件是将X射线转换为可见光的荧光屏。通过对荧光粉材料、厚度、沉积方法、衬底材料的选择，优化了荧光粉的转换效率、响应不均匀性和空间分辨率。因此，选择了厚度为10微米的Gd掺杂D22掺杂D2 O掺杂D22掺杂D2 S：Tb（P-43）。将该荧光粉与CCD X射线探测器和Si 111非对称晶体X射线放大器组合，成像系统的空间分辨率达到1.2 μ m。(2)用钴单晶在K边（7709 eV）成功地观察到了由X射线线性二向色性（XLD）引起的偏振衬度图像。这是首次在硬X射线波段观测到由XLD产生的偏振衬度像。(3)用钴多晶在K边（7709 eV）成功地观察到了由于X射线磁圆二色性（XMCD）引起的偏振衬度图像。