同步辐射单色器晶体面形控制技术研究

【作者】 屈卫德；

【导师】 周泗忠；

【作者基本信息】 中国科学院研究生院（西安光学精密机械研究所） ， 光学工程， 2008， 硕士

【摘要】 由于波荡器的引入,电子能量的提高和电子束团发散度的极度减小,第三代同步辐射光源所产生的辐射功率和功率密度比第二代光源提高两个数量级,高热负载将导致光束线各挡光元件性能降低甚至失效。单色器作为同步辐射装置最主要器件,对X射线起单色化的作用,它的分光元件的分光结果决定着实验站的最终成败。而分光元件对高热负载极其敏感,较低的功率密度都将引起非常大的分光元件形变。本论文以单色器的分光元件—衍射晶体面形变为主轴,着重做了以下几方面的工作:1.单色器晶体的面形变是单色器设计的最主要指标之一,系统研究和分析使晶体面形变的各种因素,以便采取对应的措施或应用不同的方法保证晶体面形变达到最小。这些因素包括由热负载引起的整体弯曲、局部凸起和晶格常数变化三种形变,工作环境如直接冷却流体在晶体内部产生压力和高真空环境形成负压而导致的晶面形变,机械加工的残余应力与装配夹持力引起的晶体面形变等。2.衍射晶体面产生形变,必然导致单色器摇摆曲线变宽,性能降低,甚至失效,主要研究了晶体面形变对晶体的能量分辨率、传输效率、衍射效率和束线光斑弥散的影响问题。3.减少晶体面的热吸收和采取防止衍射面变形能够提高晶体分光性能。选择合适的结构方式和制冷媒体;在高热负载下,优化衍射晶体的结构参数;利用化学机械抛光法释放晶体加工过程中的残余应力;采用以补偿为主要方式的预变形装配和冷却压弯技术;采用零变形装夹技术等方式都能够有效减小由于热负载产生的晶体面形变。4.第三代同步辐射在国内初次研制,高热负载前所未有,结合上海光源弧矢聚焦双晶单色器的研制,完成了当前具有先进性的第一水冷晶体系统的分析和设计。该系统通过结构参数优化分析,采用了扩散焊接工艺的异形晶体结构形式,在考虑冷却效率的同时,兼顾了冷却晶体的安装,克服了晶体的密封与晶体面形变问题。单色器在线测试结果显示,摇摆曲线较为理想。更多还原

【Abstract】 Power and power density produced by the third generation synchrotron radiation facility light source, improve two number-lever than that of the second generation synchrotron radiation facility light source due to utility of dulator,upgrading of electronic energy and degrading of electronic group scatering.High heat load resuts in preventing components performance degrading or invalid.Monochromator separates X-rays as one of central components of synchrotron radiation facility. Monochromatic component is sensitive for high heat load and lower power density resuts in great distortion of component. The focuses of the thesis with the surface distortions of the monochromator diffraction crystal which is Monochromatic component of monochromator as principal axis, are as follows:(1) The surface distortions of the monochromator diffraction crystal is one of monochromator design targets,and in order to taking measurements to maintain the slope error of crystal minnium,all kinds of factors resulting in the slope error of crystal surface are studied and analysed.The factors includes that three different kinds of distortions with general bowing,thermal bump and the change in the spacing between the crytak planes,occur in the crystal due to the high heat load, that the distortions is due to directly cooling water pressure and negative pressure of high vacuum surroundings, and that the distortions is due to mechanical fabrication and assembly hold stress et.al.(2) The surface distortions of the monochromator diffraction crystal results in rocking curve of the monochromator broadening width,performance debase,and extremely invalidation.Eergy differentiation,ransfer and diffraction efficiency,and beamline facula dispersion are studied and analysed.(3) Removing heat absorbing on crystal surface and preventing crystal distortion can improve diffraction performance.Choosing appropriate structure and cooling media,optimizing structure parameter of crystal in high heat load,releasing machining stress by CMP,taking beforehand distortion assembly,and cooling with bending et.al remove crystal surface distortions of the monochromator due to heat load.(4) The third generation synchrotron radiation facility is first developed with excessively high heat load. We design and analyse the first advanced water-cooling crystal system with develping SSRF sagitally focusing double-crystal monochromator .The diffraction crystal of two part are assembled by diffusion bonded,which solves the problem of airproof and distortion of crystal surface.The testing result on lines shows that rocking curve is excellent.更多还原