NSRL衍射和散射站的性能及在材料科学中的典型应用

介绍了国家同步辐射实验室二期工程X射线衍射和散射光束线实验站的建设与主要设备.利用设备采用X射线反射法,在不破坏样品的情况下得到了Si/C多层膜的结构信息;通过对标准Si粉末样品的FWHM测试表明该站可进行粉末全谱扫描;利用X射线掠入射衍射技术分析了ZnO薄膜的生长条件与结构的关系;采用X射线散斑方法直接观测了弛豫铁电体内部的纳米空间尺度的电极化团簇的空间时间构造.     

合肥国家同步辐射实验室软X射线磁性圆二色实验站建设及其初步应用

介绍了软X射线磁性圆二色谱的基本原理，合肥国家同步辐射实验室软X射线磁性圆二色实验站的主要装置，及其采用的相关技术，包括通过斩波器的同步光圆偏振度的计算及其与光通量的折中处理方法、光束线的主要组成和针对本储存环通量低所作的设计、与该实验站兼容的磁铁设计和采用的样品电流采集方式等，并介绍了各部分达到的性能指标．最后用该实验装置对不同厚度的Co多晶薄膜的自旋磁矩与轨道磁矩进行了初步研究，发现随薄膜厚度增加，样品自旋磁矩逐渐增大，而轨道磁矩逐渐减小．     

基于同步辐射光源的DEI技术在豚鼠耳蜗成像中的应用

基于同步辐射光源和单色晶体-分析晶体系统的硬X射线衍射增强成像（diffraction enhanced imaging， DEI）是一种对X射线相位信息进行成像的有效方法. 利用分析晶体微弧度量级的角敏感性，DEI可以对X射线穿透样品时产生的透射光、折射光和散射光分别进行成像，大大提高了硬X射线成像的像衬度和空间分辨率. 在北京同步辐射装置（Beijing synchrotron radiation facilities，BSRF）形貌学实验站，文中应用DEI方法对豚鼠耳蜗进行成像，获得了一系列的DEI图像；并在此基础上计算得到了表观吸收像和表观折射像. DEI图像清晰显示了耳蜗的整体结构和内部细节，甚至包括细胞水平的结构，如内外毛细胞的静纤毛和Hansen 细胞边缘等. DEI图像具有高衬度、高分辨率和明显的边缘增强等特点，在生物、医学研究和临床应用中有广阔的前景.     

用于激光等离子体X射线诊断的谱仪

为了诊断波长为0.5～0.8 nm的激光等离子体X射线,研制了一种新型的高空间和光谱分辨率的晶体谱仪.采用2个不同分光计材料、不同形状且相互垂直分布的通道可以同时获得谱线的空间和光谱分辨率.利用成像板接收光谱信号,其有效接收面积为30 mm×80 mm.讨论晶体基本参数和给出了谱仪设计参数.在中国工程物理研究院激光聚变研究中心的20 J激光器装置进行实验,两个方向的成像板同时获取得到了Al激光等离子体X射线光谱,其中水平通道的PET平面晶体获取的空间分辨率为1.73～6.88 mm,而垂直通道的Mica球面弯晶得到的光谱分辨率达到1 000～1 500.实验结果表明该谱仪适合于激光等离子体X射线的光谱学研究.     

NSRL衍射和散射站的性能及在材料科学中的典型应用

介绍了国家同步辐射实验室二期工程X射线衍射和散射光束线实验站的建设与主要设备．利用设备采用X射线反射法，在不破坏样品的情况下得到了Si／C多层膜的结构信息；通过对标准Si粉末样品的FWHM测试表明该站可进行粉末全谱扫描；利用X射线掠入射衍射技术分析了ZnO薄膜的生长条件与结构的关系；采用X射线散斑方法直接观测了弛豫铁电体内部的纳米空间尺度的电极化团簇的空间时间构造．     

血管无造影剂X射线定量相衬成像

为克服血管造影术的缺点并提高分辨率,采用X射线定量相衬成像方法进行了血管成像研究.结果表明,采用该方法进行血管成像不存在造影剂对样品的危害,有效提高了成像分辨率,可获得微血管的精确尺度.     

毛细管X光平行束透镜坪区特性的研究

玻璃对X射线的折射率接近1，无法使用传统的光学透镜对其进行会聚或平行调控．将大量毛细管按照一定方式排列组合，在符合全反射原理的情况下，对点X光源发射的X射线进行调控；着重于研究整体毛细管X光平行束透镜，利用光线追迹法进行数值模拟，设计仿真模拟程序，模拟出X射线在整体毛细管X光平行束透镜中的传播路径；通过改变毛细管的子管参数和排列方式，使毛细管X光平行束透镜的出射光束出现光束坪区，并设计出出光均匀性80%以上的毛细管X光平行束透镜；通过试验分别使用等径和变径毛细管X光平行束透镜对X点光源进行成像，验证了变径优化对出射光束均匀性的改善作用，其中变径X光平行束透镜的出射光束的发散角低至11.7 mrad．      

表面物理光束线和实验站的建设及研究进展

介绍了国家同步辐射实验室(NSRL)二期工程建设的表面物理光束线的设计参量和测试结果,以及实验站的基本配置、调试结果和自对用户开放以来取得的最新研究进展.测试和开放使用结果表明,NSRL表面物理实验站能够满足部分用户开展角分辨光电子能谱实验的需要.     

线阵技术在焊管检测中的应用

螺旋焊管管端焊缝检测方法中的胶片拍片法虽然灵敏度和分辨率高,但检测效率较低、成本高、不便于存档,图像增强器法效率高,但灵敏度、分辨率低.为此设计一套新型螺旋焊管管端焊缝检测设备,采用线扫描数字成像技术进行X射线检测.其灵敏度和分辨率优于图像增强器,检测效果达到了胶片的水平,弥补了图像增强器和胶片照相法的不足,提高了检测效率,降低了检测成本,实现了螺旋焊管无损检测的数字化.系统软件选用VC 语言进行编写,能够实现图像的降噪、焊缝提取和缺陷识别等功能.     

X射线成像技术的发展现状和趋势

医学影像学一直是诊断技术的热点 ,X射线成像设备是目前医学成像的主流设备之一 ,传统平面成像正受到新兴数字成像技术的挑战。基于 X射线穿透性成像技术的关键是 X射线发生器、探测器和成像软件的开发与改进 ,未来基于 X射线成像技术的趋势是在减少对患者的辐射剂量的同时 ,提取和处理更多的有效信息 ,为医生提供更准确、分辨率更高的医学影像。     

X射线衍射和散射光束线设计

介绍了装备在合肥扭摆磁铁光源上一条Ｘ射线光束线的设计,包括光学系统,设计参数,光束线上的两台主要设备前置环面聚焦镜和双晶单色仪．该光束线建成后将用于生物大分子晶体结构分析、高分辨Ｘ射线粉末和单晶衍射、多层膜结构以及在特殊条件下的Ｘ射线衍射与散射研究     

基于Geant 4对填充液闪毛细管阵列成像研究

基于蒙特卡罗方法的模拟程序Geant 4，分析了填充液闪毛细管阵列长度、子管截面形状、阵列层数等关键参数，给出了针对实验室X光源的毛细管阵列最优化设计；还分析了不同射线入射方向、有无吸光体对毛细管阵列成像的影响；开展了X射线对铝片透射成像的模拟实验，结果表明毛细管阵列能应用于微米量级X射线透射成像.      

Application of synchrotron source based DEI method in guinea pig cochleae imaging

Hard X-ray diffraction enhanced imaging (DEI), which is based on a synchrotron source and monochromator-analyzer-crystal system, is an effective method for imaging X-ray phase shift. Utilizing an analyzer crystal with high angular sensitivity of micro-radian, DEI can measure the transmitted, refracted and scattered X-rays when projecting onto a sample. It dramatically improves the contrast and spatial resolution of the resultant images. At the topography station of Beijing Synchrotron Radiation Facilities (BSRF), we implemented DEI method in guinea pig cochleae imaging and acquired a series of DEI images. Based on these images, the apparent absorption and refraction images were calculated. The DEI images revealed the holistic spiral structures and inner details of guinea pig cochleae clearly, even including the structures at the cellular level, such as the static cilia of hairy cells and the limbus of Hansen cell. Due to the advantages of high contrast, high spatial resolution and distinct edge-enhanced effect, DEI method promises extensive applications in biology, medicine and clinic in the near future.     

Application of synchrotron source based DEI method in guinea pig cochleae imaging

Hard X-ray diffraction enhanced imaging (DEI), which is based on a synchrotron source and monochromator-analyzer-crystal system, is an effective method for imaging X-ray phase shift. Utilizing an analyzer crystal with high angular sensitivity of micro-radian, DEI can measure the transmitted, refracted and scattered X-rays when projecting onto a sample. It dramatically improves the contrast and spatial resolution of the resultant images. At the topography station of Beijing Synchrotron Radiation Facilities (BSRF), we implemented DEI method in guinea pig cochleae imaging and acquired a series of DEI images. Based on these images, the apparent absorption and refraction images were calculated. The DEI images revealed the holistic spiral structures and inner details of guinea pig cochleae clearly, even including the structures at the cellular level, such as the static cilia of hairy cells and the limbus of Hansen cell. Due to the advantages of high contrast, high spatial resolution and distinct edge-enhanced effect, DEI method promises extensive applications in biology, medicine and clinic in the near future.     

Crystallization and preliminary X-ray crystallographic analysis of yeast prion protein Ure2p with shortened N-terminal

An orthorhombic crystal form of a recombinant yeast prion protein with shortened N-terminal, 90Ure2p, has been obtained. Crystals were grown by the vapordiffusion technique against a mother liquor containing imidazole. Crystals belong to the primitive orthorhombic lattice with the cell parameters a = 54.5 Å, b = 74.7 Å, c = 131.0 Å. The crystals diffract to beyond 3.0 Å resolution at a synchrotron beamline.     

Three-dimensional mapping of a deformation field inside a nanocrystal

Coherent X-ray diffraction imaging is a rapidly advancing form of microscopy: diffraction patterns, measured using the latest third-generation synchrotron radiation sources, can be inverted to obtain full three-dimensional images of the interior density within nanocrystals. Diffraction from an ideal crystal lattice results in an identical copy of this continuous diffraction pattern at every Bragg peak. This symmetry is broken by the presence of strain fields, which arise from the epitaxial contact forces that are inevitable whenever nanocrystals are prepared on a substrate. When strain is present, the diffraction copies at different Bragg peaks are no longer identical and contain additional information, appearing as broken local inversion symmetry about each Bragg point. Here we show that one such pattern can nevertheless be inverted to obtain a 'complex' crystal density, whose phase encodes a projection of the lattice deformation. A lead nanocrystal was crystallized in ultrahigh vacuum from a droplet on a silica substrate and equilibrated close to its melting point. A three-dimensional image of the density, obtained by inversion of the coherent X-ray diffraction, shows the expected facetted morphology, but in addition reveals a real-space phase that is consistent with the three-dimensional evolution of a deformation field arising from interfacial contact forces. Quantitative three-dimensional imaging of lattice strain on the nanometre scale will have profound consequences for our fundamental understanding of grain interactions and defects in crystalline materials. Our method of measuring and inverting diffraction patterns from nanocrystals represents a vital step towards the ultimate goal of atomic resolution single-molecule imaging that is a prominent justification for development of X-ray free-electron lasers.     

基于阶跃恢复二极管的梳状波设计

在许多领域,直接倍频仍作为频率合成的主要手段。阶跃恢复二极管单级倍频次数可达10-20以上．可由晶体振荡器直接倍频到微波,得到稳定的频率输出[1-2]。本文介绍了采用阶跃恢复二板管产生梳状波的方法,具有工作频带宽、频率稳定度高、噪声低、电路简单等优点,经制作电路板验证,电路的频带,单边带相位噪声和频率分辨率都达到了预先的设计要求,取得了预期的效果。     

曲面切槽晶体单色器设计

讨论了曲面切槽单色器的工作原理，并依据合肥光源上的XAFS光学参数，设计加工出晶体的切槽曲面，测量了曲面的形位误差，进而分析了曲面加工、定位误差以及入射光的束宽对单色器分光性能的影响．在测量所得的加工误差下，考虑由于束流宽束给衍射性能造成的影响，计算了实际晶体相对于理想晶体的理论衍射效率．计算结果证明该晶体单色器完全适用于合肥光源的XAFS光晕系统．     

Lensless imaging of magnetic nanostructures by X-ray spectro-holography

Our knowledge of the structure of matter is largely based on X-ray diffraction studies of periodic structures and the successful transformation (inversion) of the diffraction patterns into real-space atomic maps. But the determination of non-periodic nanoscale structures by X-rays is much more difficult. Inversion of the measured diffuse X-ray intensity patterns suffers from the intrinsic loss of phase information, and direct imaging methods are limited in resolution by the available X-ray optics. Here we demonstrate a versatile technique for imaging nanostructures, based on the use of resonantly tuned soft X-rays for scattering contrast and the direct Fourier inversion of a holographically formed interference pattern. Our implementation places the sample behind a lithographically manufactured mask with a micrometre-sized sample aperture and a nanometre-sized hole that defines a reference beam. As an example, we have used the resonant X-ray magnetic circular dichroism effect to image the random magnetic domain structure in a Co/Pt multilayer film with a spatial resolution of 50 nm. Our technique, which is a form of Fourier transform holography, is transferable to a wide variety of specimens, appears scalable to diffraction-limited resolution, and is well suited for ultrafast single-shot imaging with coherent X-ray free-electron laser sources.     

光束线和实验站真空保护与控制系统(英文)

本文概述了合肥光源光束线的基本组成以及光束线真空联锁保护与控制系统的关键设备———超高真空快速关闭阀及其控制器,给出了光束线真空系统的保护与控制要点以及光束线真空事故的联锁保护实例,阐述了新建超导扭摆磁铁的ＸＡＦＳ光束线和实验站的真空联锁保护与控制系统的研制．