高压衍射实验中的同步辐射光束的定位

 应用同步辐射光源进行高温高压原位能量色散X射线衍射实验,入射X射线光束定位是关键。北京同步辐射实验室高压衍射站引入四刀光阑扫描系统,实现调光定位自动化,简化调光手续,提高实验效率,为高压衍射实验站的用户进行实验提供了方便。     

同步辐射光源在地球深部矿物研究中的应用

来自地球深部的矿物可能记录了地球形成和早期演化的历史，探索地球深部物质组成和它们形成的物理化学环境是一个十分前沿的科学问题．同步辐射X射线能量色散法对于解决微细矿物及包裹体矿物的晶体结构具有巨大的优势和潜力．在美国纽约长岛布鲁克海文国家实验室，利用同步辐射光源（Beamline X17C）和能量色散X射线衍射方法，开展了西藏铬铁矿中地幔深部矿物及中国大陆科学钻探钻孔岩心样品中地幔异常矿物的晶体结构分析，发现了一批新矿物种属和特殊的晶体结构，来自大陆科学钻探岩心样品的铁磷矿和西藏金刚石是两个例证．     

低能区衍射限储存环同步辐射的应用浅析

在科学技术新需求的推动下,同步辐射光源持续往前发展。目前,同步辐射装置发展已历经三代,正处于第四代同步辐射光源蓬勃发展阶段。基于衍射极限储存环的同步辐射装置是第四代同步辐射光源的典型代表之一。第四代同步辐射光源主要发展趋势是进一步减小电子束流发射度,使光源具有极好的横向相干性,以及产生圆截面辐射的能力。如果束流发射度降至光学衍射极限“辐射波长/4π”,其亮度比第三代同步辐射光源高2个数量级。这种同步辐射光源在性能上发生的质的飞跃,将给同步辐射实验技术带来实质性的突破,从而给前沿科学技术研究和现代产业发展带来全新的机遇。从国际同步辐射发展趋势入手,首先介绍低能区衍射限储存环光源的特色和性能,然后介绍其带来的同步辐射实验技术的进步,并浅析低能区衍射限储存环光源在材料科学、能源科学、生命科学和环境科学上的应用,以及其带来的产业机遇。最后,总结和展望了低能区衍射限储存环光源带来的技术突破和潜在的应用前景。     

两块晶体衍射增强成像方法研究

在北京同步辐射装置4W1A光束线形貌学实验站用两块晶体开展了衍射增强成像方法的实验和理论研究.研究了晶体热膨胀对两块晶体衍射增强成像的影响,分析的结论表明,晶体转轴垂直于同步辐射偏振面能基本避免晶体热膨胀的影响,获得较好的成像质量.实验结果证实了分析的正确性. 关键词： 相位衬度成像 同步辐射 晶体衍射     

高压衍射光路的准直与散射背底屏蔽

在同步辐射高压X射线光路中,通过建立准直系统屏蔽来自金刚石的康普顿散射和实验环境中的杂散光,有效地降低了散射背底.通过两次专用光期间的测试表明,准直系统对于信噪比的提高有较为显著的效果,使以前不能进行有效测量的一些高压样品可以得到较好的能量色散X射线衍射数据,并为进行MPa压力下的原位测试提供了有效的手段.     

BeO的高压能量色散X射线衍射研究

在北京同步辐射高压站进行了BeO高压原位能量色散X射线衍射实验. 在从常压下加压至42GPa的过程中,BeO保持常压的六方纤锌矿结构(Wurtzite),没有发生相变,晶胞体积随着压力增加单调减小.用Murnaghan方程拟合出BeO在0.6—42.0GPa范围内的P-V状态方程,得到体弹模量K₀=276GPa.     

同步辐射在古陶瓷研究中应用的现状和展望

概述了同步辐射光源的历史和优点,对同步辐射X射线荧光、X射线吸收精细结构、同步辐射X射线衍射等方法在古陶瓷工艺、产地等方面的应用现状进行了总结,并展望了同步辐射在古陶瓷研究中的应用前景.     

衍射增强成像方法中两种晶体排列方式的对比研究

北京同步辐射装置(BSRF)4W1A光束线形貌学实验站近两年开展了两块晶体的衍射增强成像实验研究，在实验中，晶体转轴垂直于同步辐射偏振面时的图像质量好于晶体转轴平行于同步辐射偏振面时获取的图像.本文从X光强度分布、单色器晶体的热膨胀、空间分辨率、角分辨率等方面系统地对两种晶体几何排列方式进行了比较研究.实验和理论分析的结果表明，晶体转轴垂直于同步辐射偏振面时单色器晶体上的热膨胀对成像的影响较小，因而获得了更好的成像质量. 关键词： 同步辐射 衍射增强成像 晶体衍射     

同步辐射X射线衍射的谐波成分计算

结合动力学衍射公式和同步辐射谱,导出了衍射谐波的计算公式。作为应用的例子,计算了完美Si单晶常用的几个衍射晶面的同步辐射X射线衍射的谐波成分。数据适用于北京正负电子对撞机同步辐射实验室形貌站(4W1A光束线)。结果表明:(333)衍射中谐波成分丰富,而其它衍射中谐波成分较弱。 关键词：     

C70纳米/亚微米棒的高压相变研究

通过溶剂挥发法获得了准一维C70纳米/亚微米棒状晶体,直径为～500nm, 长度为～10μm,呈六方密堆(hcp)结构. 利用金刚石对顶砧(DAC)高压装置,采用同步辐射能量色散X光能量色散衍射方法(EDXD)和高压拉曼光谱,研究了压力对C70纳米/亚微米棒结构的影响, 实验中最高压力为26.1GPa. 结果表明, 在准静水压条件下,在23.3—26.1GPa压力范围内, hcp结构的C70纳米/亚微米棒发生了由hcp结构向非晶化的相变,相变压力比体材料高约5GPa, 该相变是不可逆相变, 而且该相变是由于C70在高压下笼状结构被破坏所导致的.     

Synchrotron Radiation Facilities in China

Synchrotron radiation activities in China date back to the late 1970s. With the large increase of investment in science by the Chinese central government to promote the development of science and technology in China, quite a few large scientific projects were proposed by the scientific community, among which were Beijing Electron-Positron Collider (BEPC) and Hefei Synchrotron Radiation Light Source (HLS). The major aim of BEPC was for the studies of high energy particle physics with a parasitic synchrotron radiation facility, i.e., the so-called Beijing Synchrotron Radiation Facility (BSRF). It started operation in 1991 and became the first synchrotron radiation facility in China. As a parasitic facility, BSRF operated a few months a year and played an important role in fostering the synchrotron radiation user community in China. The HLS, a dedicated synchrotron radiation facility, came into operation almost at the same time as BSRF. As a lower energy synchrotron radiation facility, it aimed mostly at the applications of synchrotron radiation VUV wavelength range. Both BSRF and HLS were upgraded again due to strong demands from users. The rapid development of synchrotron radiation applications and facilities in the world in the 1980s and early 1990s spurred the great interest of Chinese scientists to build an advanced synchrotron radiation light source. A third generation light source was first proposed in mainland China in 1993 and was later shaped as the Shanghai Synchrotron Radiation Facility (SSRF) in 1995.     

Measurement of Radiation Dose Level of Synchrotron Radiation Experimental Hall of BEPC

This paper describes the radiation source and its characteristics of the Synchrotron Radiation Experimental Hall of BEPC,the radiation measuring method and measured results.It has been found that the radiation dose level of the Synchrotron Radiation Experimental Halls is closely correlative with the relative location of the Experimental Halls to the injection points of the electron and positron beams,the thicknesses of the shielding walls,the times and efficiencies of the beam injections.     

同步辐射X线光刻

X线光刻是未来亚微米应用的重要微光刻技术、近年来,同步辐射X线光源的应用是技术上一个重要发展,本文叙述了同步辐射X线光刻在微电子技术未来发展中的作用、现状及其基本技术问题。并介绍了我国同步辐射X线光刻的发展情况。     

Synchrotron radiation is not a blackbody but a graybody

Though synchrotron radiation and blackbody radiation are considered as completely different phenomena, spectral shape of synchrotron radiation is somewhat similar to that of the blackbody radiation. Synchrotron radiation is a graybody radiation with a finite value of emmisivity, which varies as a function of wavelength. Copyright © 2007 John Wiley & Sons, Ltd.     

AOFSRR 2014 in Taiwan

The Asia-Oceania Forum for Synchrotron Radiation Research (AOFSRR) was formally established by Australia, China, Japan, South Korea, Singapore, Taiwan, and Thailand in 2006. Its objective is to strengthen the collaboration, as well as the inter-communication, among the synchrotron radiation facilities and to promote synchrotron radiation sciences and accelerator-based research in the Asia-Oceania region. Regular meetings have been organized to uphold its objective. The first scientific meeting of AOFSRR took place at KEK, Japan, in 2006. Member countries have been taking turns to organize meetings: Taiwan (NSRRC, 2007), Australia (Australian Synchrotron, 2008), China (SSRF, 2009), South Korea (POSTEC, 2010), Thailand (SLRI, 2012), and Japan (SPring-8, 2013). In 2014, the National Synchrotron Radiation Research Center (NSRRC) hosted the Eighth Asia-Oceania Forum for Synchrotron Radiation Research (AOFSRR 2014) from September 15th to 18th in Hsinchu, Taiwan. The NSRRC is located in the Hsinchu Science Park, within an hour's drive from Taipei, the largest city in Taiwan. Hsinchu is a city not only composed of historical landmarks but also the heartland of high-tech semiconductor industries in Taiwan.     

上海光源同步辐射空间干涉仪研制

 研制了上海光源同步辐射空间干涉仪,用于储存环束团横向截面尺寸及发射度的精确测量。对干涉仪工艺设计中的光路参数、关键设备选型、数据处理方法及数据采集处理软件结构进行了分析讨论。结合束流实验完成了系统调试及运行参数优化,结果表明,CCD增益系数与曝光时间设置对测量精度有显著影响,增益系数设为0 dB,曝光时间设为200 ms时,随机测量误差可控制在μm量级。对上海光源储存环横向束斑尺寸进行了精确测量,结果表明:空间相干度曲线近似为高斯分布,可以采用单一空间频率的相干度测量值进行快速束斑尺寸计算;水平束斑尺寸实测值为52.4 μm,与理论值预期值53.0 μm相比,差异小于2%;系统测量误差约为5.5%,主要误差来源为相干度随机测量误差。     

机器学习在储存环轨道校正中的应用研究

X射线同步辐射光源,是现代科学研究中最强大的工具之一。位于中国上海的上海光源,是一台能量为3.5 GeV的先进的第三代中能同步辐射光源。第三代同步辐射光源要提供高亮度、高稳定性的同步辐射来满足实验条件要求苛刻的前沿研究,因此对束流的轨道稳定性有很高的要求。为此,采用机器学习算法进行电子束轨道的控制和反馈。这种基于神经网络的轨道校正方法不依赖于具体的响应矩阵,建立非线性映射关系,并且还可以进行连续的在线再训练,对上海光源的轨道校正和提高束流轨道稳定性有重要意义。     

新型超快探测器性能研究

 为提高强g 场超快辐射探测器抗信号堆积的性能，可采用BaF₂（La）与快的光电器件组合的技术途径。用同步辐射闪烁荧光衰减谱仪和X光激发发射谱仪测量了国产不同掺La浓度的BaF₂晶体抑制快慢成分之比，探讨掺La对抑制慢成分的机理，研究了BaF₂（La）抗辐照性能。并用同步辐射测量BaF₂（La）与GD40Z光电管组成超快辐射探测器的快慢成分抑制比。     

X-Ray Cherenkov Radiation in an Absorbing Medium with Finite Dimensions

Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques - The spectral-angular characteristics of the electromagnetic radiation produced during the propagation of fast charged...     

Synchrotron radiation in curved space—time

Synchrotron emission by ultrarelativistic particles moving in a magnetic field in curved space-time is examined by the method of local coordinates. Generally covariant equations are obtained for the radiation spectrum in the classical and quantum cases. It is shown that the relative magnitude of the quantum corrections to the radiation spectrum increases with particle motion near the event horizon in the Kerr metric. The limit of geodesic synchrotron radiation is examined.