基于X射线荧光光谱的温稠密物质离化分布实验方法研究  

Experimental method for warm dense matter ionization distribution based on X-ray fluorescence pectroscopy

作　　者：张志宇[1] 赵阳[1] 青波[1] 张继彦[1] 林成亮 杨国洪[1] 韦敏习[1] 熊刚[1] 吕敏 黄成武[1] 朱托[1] 宋天明[1] 赵妍[1] 张玉雪 张璐[1] 李丽灵[1] 杜华冰[1] 车兴森[1] 黎宇坤[1] 詹夏宇[1] 杨家敏[1] Zhang Zhi-Yu;Zhao Yang;Qing Bo;Zhang Ji-Yan;Lin Cheng-Liang;Yang Guo-Hong;Wei Min-Xi;Xiong Gang;LüMin;Huang Cheng-Wu;Zhu Tuo;Song Tian-Ming;Zhao Yan;Zhang Yu-Xue;Zhang Lu;Li Li-Ling;Du Hua-Bing;Che Xing-Sen;Li Yu-Kun;Zhan Xia-Yu;Yang Jia-Min(Laser Fusion Research Center,China Academy of Engineering Physics,Mianyang 621900,China;Institute of Applied Physics and Computational Mathematics,Beijing 100088,China)

机构地区：[1]中国工程物理研究院激光聚变研究中心,绵阳621900 [2]北京应用物理与计算数学研究所,北京100088

出　　处：《物理学报》2024年第1期241-247,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12004351,11734013)资助的课题。

摘　　要：受温度及密度等环境效应影响,温稠密物质的电子结构发生显著变化,其理论描述非常复杂,精密实验测量亦极其困难.本文发展了基于X射线荧光光谱研究温稠密物质离化分布的实验方法,结合理论研究有助于深入理解温稠密物质的电子结构变化.在万焦耳激光装置上,设计特殊构型黑腔复合加载产生数十eV、近固体密度的稠密Ti物质,利用激光辐照V产生的热发射线泵浦Ti的荧光,并采用晶体谱仪诊断样品的X射线荧光光谱.实验中获得冷样品和加载样品的荧光光谱,观测到加载样品K_(α)及K_(β)荧光谱线相对于冷样品光谱在高能侧的显著变化,结合理论计算解释了加载样品荧光谱线的变化主要来源于其温度上升后离化分布的改变,建立了基于X射线荧光光谱的温稠密物质离化分布实验研究能力.Warm dense matter(WDM),a state of matter that lies at the frontier between condensed matter and plasma,is one of the main research objects of high energy density physics(HEDP).Comparing with the isolated atom,the electron structure of WDM will change because of the influence of density and temperature effect.Both the accurate theoretical representation and the accurate experimental study of WDM electron structure are challenging,as it is strongly coupled and partially degenerated.In this work,an experimental method of studying the ionization distribution of WDM based on X-ray fluorescence spectroscopy is developed.In the experiment,in a specially designed hohlraum,warm and dense titanium with several tens of electron volts and nearly solid density is produced by simultaneous driving of high-energy X-ray heating and shock compression.Then,using the characteristic line spectrum emitted by the laser irradiation on pump material(Vanadium) as a pump source,the titanium emits fluorescence.The X-ray fluorescence spectra of titanium with different states(cold sample,1.8–4.5 g/cm~3 and 1–25 eV) are diagnosed by changing the experimental strategy.The experimental results indicate that the line profiles of K_α and K_β fluorescence spectrum of the heated sample change obviously compared with those of the cold sample.According to the theoretical calculation of the twostep Hartree-Fock-Slater(TSHFS) method,the main reason for the change of the line profile is the change of ionization distribution caused by temperature rising.The future work will focus on optimizing the experimental method of X-ray fluorescence spectrum,such as improving the spectrum resolution,characterizing the temperature and density experimentally,obtaining a set of ionization distribution data,and then studying the influence of dense environment on electronic structure.

关 键 词：温稠密物质 电子结构 离化分布 X射线荧光光谱 

分 类 号：O469[理学—凝聚态物理]