~3He气体极化前预处理系统的研发和性能验证

发布时间：2018-11-25 18:56

【摘要】：目前,~3He已经广泛应用于中高能核物理领域及生物医学领域,特别是在肺部诊断中,基于超极化~3He气体的磁共振成像可以提供清晰的肺部病灶图像,为实现肺部疾病的早期诊断提供了可能。本论文主要基于碱金属自旋交换光泵浦的原理,设计并制作出基于超极化~3He气体的极化腔,并在自主设计的~3He极化装置中实现纯Rb和Rb-K两类交换介质下~3He的极化,并对极化后的超极化~3He气体进行提取和保存,使其应用于低场磁共振的肺部成像。主要工作内容和成果如下:首先,比较不同碱金属与~3He间的自旋交换率和自旋弛豫率,并探索当使用混合碱金属作为交换介质时,不同碱金属蒸汽在极化腔中的最佳蒸汽密度比D值;讨论极化腔表面积与体积的比例对于~3He极化度的影响。其次,根据具体的实验要求,设计并搭建用于超极化~3He气体的极化腔及其附属支管,讨论不同的材料在极化过程中对~3He气体的影响,并对管路的制作流程进行详细阐述。再次,针对极化腔的制作进行抽真空充气系统的设计和搭建,对搭建的抽真空充气管路进行测试使其满足设计需求,并在此基础上总结相应实验气体的充气测量的方法。此外,设计并搭建基于超极化~3He气体的提取装置,比较不同材料对超极化~3He气体退极化率的影响,并制作出储存极化气体的采样袋。最后,利用搭建完成的极化腔和抽真空充气系统以及配置好的碱金属混合物制作出基于超极化~3He气体的极化腔,并使用电子顺磁共振方法(EPR)对极化腔中的超极化~3He气体的极化度进行测量,得到输运曲线和自旋弛豫曲线。
[Abstract]:At present, ~ 3He has been widely used in the field of middle and high energy nuclear physics and biomedicine, especially in the diagnosis of lung. Magnetic resonance imaging based on hyperpolarizing ~ 3He gas can provide clear images of lung lesions. It provides the possibility for early diagnosis of lung diseases. Based on the principle of alkali metal spin-exchange optical pump, a polarizing cavity based on hyperpolarization ~ 3He gas is designed and fabricated in this paper. The polarization of ~ 3He is realized in the self-designed ~ 3He polarizing device under two kinds of switching media, pure Rb and Rb-K. The hyperpolarized ~ 3He gas was extracted and preserved for low field magnetic resonance imaging. The main contents and results are as follows: firstly, the spin exchange rate and spin relaxation rate between different alkali metals and ~ 3He are compared, and when mixed alkali metals are used as exchange medium, The optimum vapor density ratio D of different alkali metal vapor in polarized cavity; The effect of the ratio of surface area to volume of polarized cavity on the polarizability of ~ 3He is discussed. Secondly, according to the specific experimental requirements, the polarization cavity for hyperpolarized ~ 3He gas and its subsidiary branch tubes are designed and built. The effects of different materials on the ~ 3He gas during the polarization process are discussed, and the fabrication process of the pipeline is described in detail. Thirdly, the vacuum inflatable system is designed and built for the fabrication of the polarized cavity, and the vacuum inflatable pipeline is tested to meet the design requirements. Based on this, the method of gas inflatable measurement for the corresponding experimental gas is summarized. In addition, an extraction device based on hyperpolarization ~ 3He gas was designed and built to compare the effects of different materials on the depolarizability of hyperpolarized ~ 3He gas, and a sample bag was made to store the polarized gas. Finally, the polarizing cavity based on hyperpolarization-3He gas is fabricated by using the completed polarization cavity, vacuum inflatable system and the configured alkali metal mixture. The electron paramagnetic resonance (EPR) method is used to measure the polarizability of the hyperpolarized ~ 3He gas in the polarized cavity. The transport curves and spin relaxation curves are obtained.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R563

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