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1、 用于激光等离子体硬 X射线诊断的透射式弯晶谱仪研究重庆大学硕士学位论文（学术学位）学生姓名：钱凤指导教师：肖沙里教授曹磊峰研究员专业：光学工程学科门类：工学重庆大学光电工程学院二 O一三年五月 Study on Transmission Curved CrystalSpectrometer for Laser-Plasmas Hard X-rayDiagnosisA Thesis Submitted to Chongqing Universityin Partial Fulfillment of the Requirement for theMasters Degree of Enginee
2、ringByQian FengSupervised by Prof. Xiao ShaliProf. Cao LeifengSpecialty：Optical EngineeringCollege of Opto-electronic Engineering ofChongqing University, Chongqing, ChinaMay 2013 中文摘要摘要受控热核聚变可以为人类带来持久且清洁的能源，是世界科学研究的一个重点，激光惯性约束聚变(ICF)是它实现的一个有效途径。有望实现激光惯性约束聚变的方式有很多，其中快点火模型显示出了很多优势并迅速成为一个研究热点。激光等离子体相互作
3、用产生的超热电子对热核材料的点燃非常重要，因此对超热电子的研究具有非常重大的意义。激光等离子体辐射出来的轫致辐射谱中含有很多超热电子的信息，因此可以通过对轫致辐射能谱的诊断推导出超热电子的行为特性。在 K壳层光谱诊断技术中，需要测量的谱线能量通常都在几十 keV范围，通过这些硬 X光谱诊断可以理解超强激光脉冲产生等离子体中的激光能量分布，电离分布以及 X射线转化效率等。随着国内各种激光装置的不断建造和升级，对硬 X射线诊断变得越来越重要。与其他诊断方式（如单光子计数型 CCD）相比，透射式弯晶谱仪具有测谱范围宽、分辨能力高等优点，目前已广泛运用于强激光等离子体相互作用产生的硬 X射线测量当中。
4、本文将根据星光激光装置实验对硬 X射线能谱诊断的需要设计和研制一台透射式弯晶谱仪。以下是本文主要内容：首先介绍了透射式弯晶谱仪的基本理论。包括晶体的 X射线衍射理论，透射式弯晶谱仪的基本原理和结构组成等。透射式弯谱仪采用的是 Cauchois-Johann型结构，属于聚焦型光谱仪器。谱线在罗兰圆上聚焦，因此谱仪的探测面通常置于晶体后晶体曲率半径 R处。其次，利用谱仪的几何光学结构对谱仪的各个设计性能参数进行了分析研究。分析了谱仪使用的分光晶体的晶格常数，晶体曲率半径，以及光源到晶体的距离对测谱范围和分辨能力的影响情况。研究了探测器位置，光源尺寸和探测器有效空间分辨对能谱分辨能力的影响。探讨了引
5、起探测面上谱线偏移的原因。这些理论分析对透射式弯晶谱仪的系统设计和研制提供了理论指导，奠定了基础。然后，根据理论分析方法，结合激光装置的实际情况对透射式弯晶谱仪进行具体设计，包括光学设计和机械结构设计。本文将透射式弯晶谱仪分为分光系统，探测记录系统和瞄准对中系统三个系统分别进行设计。给出了各个系统内各元件的选择原因。研制完成的透射式弯晶谱仪可以实现 1260keV范围的硬 X射线能谱测量，在低能段的能谱分辨能力 E/E300。谱仪可以实现真空中实时在线的瞄准和测量。瞄准光源是通过一个真空光纤激光系统将靶室外的光束引入真空靶室内部。最后利用阳极为 Mo的 X射线管实验和 500TW激光装置实验对
6、研制的谱仪进行测试。对实验结果进行了分析，结果表明谱仪对能量在 20keV以下的谱线的分I 重庆大学硕士学位论文辨能力 E/E377，满足设计要求。同时也证明了瞄准对中系统设计的合理性和正确性。关键词：光谱诊断，透射式弯晶，硬 X射线，设计参数，分辨能力II 英文摘要ABSTRACTControlled thermonuclear fusion has become an important research task in theworld science，for its sustainable and clean merit as an energy resource. One effec
7、tiveway to realize controlled thermonuclear fusion is laser Inertial Confinement Fusion(ICF). There are many approaches to achieve ICF, among them is fast ignition whichshows a promising future and quickly becomes a hot research topic. According to thesupposition of fast ignition, nuclear fuel ignit
8、ion is significantly functioned by the hotelectrons produced by the interaction of laser with plasma. Thus, the research of hotelectron plays an important role in the intensity field physics. Plentiful informationabout hot electrons is contained in the bremstruhlung spectrum emitted from theinteract
9、ion of laser with plasma, hence we can characterize the hot-electron energydistribution of the laser generated plasmas by diagnosing the continuum x-ray spectrum.The implementation of K-shell spectroscopy (mang energy above 10keV) diagnostictechniques is helpful to understand the laser energy distri
10、bution, ionization distribution,and X-ray conversion efficiency in plasmas produced by an intense femtosecond laserpulse. With the building and development of many kinds of laser devices in China, hardX-ray spectroscopy diagnostic attracts more and more interests. Transmission curvedcrystal spectrom
11、eter has been broadly used in laser-plasmas hard X-ray diagnosisbecause of its wider energy range and higher resolving power compared to otherdiagnostic methods (such as the single-photon counting CCD). In this paper, atransmission curved crystal spectrometer for XG- laser device is developed.Firstl
12、y, the basic theories of transmission curved crystal spectrometer such as thecrystal X-ray diffraction and the basic schematic are introduced. This kind ofspectrometer is based on Cauchois-Johann type, and belongs to focusing spectrometer.The spectral line is focused on the Rowland circle. X-ray spe
13、ctrum is recorded by theplanar detector that intersects the focusing circle whose diameter equals to the radius ofcurvature of crystal.Secondly, by means of the spectrometer optical geometry, theoretical analysis andnumerical simulation are performed to investigate the dependence of the energy range
14、and resolving power on various design parameters (crystal lattice spacing, crystalbending radius, displacement of source to crystal). In addition, the influence of sourcesize, detector location and the effective detector resolution on the resolving power ofIII 重庆大学硕士学位论文spectra is analyzed. Also, the reasons of the shift of spectral line on the detection planeare discussed. Such theoretical analysis provides a theoretic guide for the system designand fabrication of the transmission curved crystal spectrometer.Thirdly，according to the theoretical analysis and practical requirements, thedeta
