能量连续可调激光康普顿散射光源的研制和相关应用研究

发布时间：2018-01-27 04:21

本文关键词： 激光康普顿散射 X/γ射线源相互作用腔连续可调能量定标 γ光CT　出处：《中国科学院研究生院(上海应用物理研究所)》2017年博士论文　论文类型：学位论文

【摘要】：激光康普顿散射(Laser Compton Scattering-LCS)光源具有高通量、准单色、短脉冲、高极化度、可小型化等特点。其在基础科学研究,医学,工业,材料乃至国家安全领域都有重要的应用。目前,LCS光源的实验及应用研究已成为国际上的研究热点。根据国际发展趋势和国内用户需求,我们提出在上海光源大科学平台上建设高性能的LCS伽玛光装置—上海激光电子伽玛源(Shanghai Laser Electron Gamma Source-SLEGS)。SLEGS研制中的关键技术难题有:(1)高真空下激光入射角连续可调技术,(2)满足激光入射角连续可调的同时保证激光和电子的μm量级位置同步和ps量级时间同步。为此我们提出研制SLEGS的样机SINAP-III,在样机上实验新的技术手段,为SLEGS的建造积累经验。在此背景下,本文在LCS光源的研制和LCS光源的γ光应用这两方面做了较为深入的研究。在光源的研制方面,本文首先介绍了整个SINAP-III光源研制中各个子系统的研制进展。之后详细讲解了对其中核心部件相互作用腔的设计过程。本论文提出了一个适用于真空内旋转的光路结构,并针对SINAP-III的设计指标要求和实际的实验空间限制对光路的元件的布局做了优化。同时,设计了相关的调节和观测部件,并对各部件的精度提出了要求。这一设计实现了大范围(20°-160°),高精度(步长小于0.01°)的激光入射角调节,是连续、精确(能量调节精度优于0.1%)调节LCS光能量的新途径,可以推广到其他的LCSγ光源装置上,极大地拓展LCSγ光源的能量范围。在光源的应用方面,本论文提出了一种基于LCSγ能谱的康普顿边的能量定标方法学。该方法可以在大能量范围内对特定能量的邻域做非常小步长的定标,解决了γ探测器高能端用外推插值法时由于探测器响应的线性度变差带来的偏差。本文用SINAP-III的设计参数做了模拟测试,定标的相对不确定度δEmax在25keV到300keV的范围内小于1.6%,在300keV到740keV的范围内小于0.5%。本论文开展的另一项LCSγ光源的应用研究是基于LCSγ光的CT。该研究是在目前全球最亮的LCS光源HIGS上完成的。我们优化了光源能量,设计了测试用的模型和曝光时间,并对透射投影的γ光强度做了归一化修正。经过实验测试,模型重建后的空间分辨率优于1mm(10Lp/cm),对比度分辨率优于0.03mm-1,可以实现较准确的元素分辨。
[Abstract]:Laser Compton Scattering-LCSs have high flux, quasi monochromatic, short pulses and high polarizability. It can be miniaturized. It has important applications in basic scientific research, medicine, industry, materials and even national security. The experimental and applied research of LCS light source has become a hot spot in the world, according to the international development trend and the domestic user demand. We propose to build a high performance LCS gamma ray device on the Shanghai Light Source platform, which is called Shanghai Laser Electron Gamma Source (. The key technical problems in the development of Shanghai Laser Electron Gamma Source-SLEGS).SLEGS are: 1). Laser incident angle continuously adjustable technology in high vacuum. 2) the laser incident angle can be adjusted continuously, and the position synchronization of laser and electron at 渭 m level and the time synchronization of PS magnitude are ensured. Therefore, a prototype SINAP-III of SLEGS is proposed. To test new technical means on the prototype, to accumulate experience for the construction of SLEGS. In this paper, the development of LCS light source and the application of 纬 light of LCS light source are studied in depth. This paper first introduces the development of each subsystem in the development of SINAP-III light source, and then explains the design process of the interaction cavity of the core components in detail. The structure of a rotating optical path in a vacuum. According to the design requirements of SINAP-III and the actual experimental space constraints, the layout of the light path elements is optimized. At the same time, the related adjustment and observation parts are designed. The requirements for the accuracy of each component are put forward. The design achieves a wide range of 20 掳-160 掳and a high precision (step less than 0.01 掳) laser incident angle adjustment, which is continuous. A new way to adjust LCS light energy accurately (energy regulation accuracy is better than 0.1) can be extended to other LCS 纬 light source devices. The energy range of LCS 纬 light source is greatly expanded. In this paper, an energy calibration method for Compton edge based on LCS 纬 energy spectrum is proposed. This method can be used to calibrate the neighborhood of specific energy in a large energy range with very small step size. The deviation caused by the linear variation of the detector response is solved when the extrapolation interpolation method is used at the high energy end of the 纬 -detector. The design parameters of SINAP-III are used to do the simulation test in this paper. The relative uncertainty 未 Emax of calibration is less than 1.6% in the range of 25keV to 300keV. In the range of 300keV to 740keV, it is less than 0.5 Kev. Another LCS 纬 light source applied in this thesis is based on LCS 纬 light. This study is the brightest L in the world at present. CS light source on the HIGS. We optimized the light source energy. The model and exposure time were designed, and the intensity of 纬 -ray of transmission projection was normalized. The spatial resolution of the reconstructed model was better than 1mm / 10Lp / cm after experimental test. The contrast resolution is better than 0.03mm-1, which can achieve more accurate element resolution.
【学位授予单位】：中国科学院研究生院(上海应用物理研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN24

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