摘要
透射X射线显微镜(transmission X-ray microscope,TXM)是高精密度的尖端X射线成像设备,是现代科学技术的结晶,可以在纳米尺度上进行无损成像,为物理学、生命科学、材料学和化学等领域的众多科学问题提供了有力的研究工具.虽然国内外很多同步辐射装置都建立了以TXM为核心的纳米CT实验站,但是目前国际上只有个别企业能提供商业化的实验室TXM.究其原因,主要是该仪器涉及众多高难度的工程技术问题,诸如:高亮度实验室X射线源、高分辨率X射线光学元器件、高精度样品台、高灵敏度探测器、仪器对温度和振动等环境因素的超高要求等.为了提高研发高端X射线成像仪器的水平,需要逐个突破在研发X射线纳米CT过程中遇到的技术瓶颈.本文主要讨论了工作能量为5.4 keV的实验室TXM的仪器设计,以及全场成像实验结果.该仪器工作在吸收衬度模式下,成像视野达到了26μm,可以对30 nm线宽的特征结构实现清晰的成像,西门子星测试卡的功率谱曲线表明该仪器具有分辨半周期为28.6 nm线对结构的潜力.
Transmission X-ray microscope(TXM)is a high-precision,cutting-edge X-ray imaging instrument,which is a marvel of modern science and technology.It enables non-destructive imaging on a nanoscale,providing a powerful research tool for various scientific fields such as physics,life science,materials science,and chemistry.Although many synchrotron radiation facilities at home and abroad have established nano-CT experimental stations with TXM as the core,currently only a few companies internationally can provide commercial TXM instrument based on laboratory X-ray sources.The primary reason is that this instrument involves numerous engineering challenges,including high-brightness laboratory X-ray sources,high-resolution X-ray optical elements,high-precision sample stage systems,high-sensitivity detectors,and extremely strict requirements for environmental factors such as temperature and vibration.In order to promote the development of high-end Xray imaging instruments,it is necessary to overcome the technological bottlenecks encountered in the development of X-ray nano-CT.Discussed in this work mainly are the instrument design of a laboratory transmission X-ray microscope with working energy of 5.4 keV and the results of full-field imaging experiments.To start with,the design of the TXM instrument is introduced in detail.The TXM instrument is equipped with several key components,including laboratory X-ray source,condenser,sample stage module,zone plate,and imaging detector.The TXM instrument adopts a modular vibration isolation design and is equipped with a dedicated temperature control system.The main imaging magnifications of the TXM instrument are 50×,75×,and 100×,and the corresponding optical parameters and photos are introduced.The X-ray source used is a micro-focus X-ray source,operating in Cr target mode,with a focal spot size of 20μm and a Ka characteristic spectrum brightness of 5×10^(9)photons/(mm^(2)·mrad^(2)·s)The X-ray source provides illumination for the sample after being focused by an ellipsoidal condenser.The outer ring of the condenser's illumination ring corresponds to a numerical aperture(NA)of NA_(2)=3.196 mrad,and the inner ring corresponds to a numerical aperture of NA_(1)=1:9086 mrad.Under these conditions,the limit resolution of this TXM instrument is 22 nm.The zone plate has a diameter of 70μm,a focal length of 8.7mm,and 616 zones.The TXM instrument uses a highresolution optical coupling detector equipped with a scientific-grade CMOS camera with an effective pixel size of 7.52μm.The optical coupling detector is equipped with 2×and 10×high numerical aperture objectives.When the TXM instrument magnification is 50×,the effective pixel size of the TXM instrument is 15 nm.In addition,a gold resolution test card is used as the sample to determine the imaging field of view of the TXM instrument by observing the size of the imaging area of the test card on the detector,and to determine the imaging resolution of the TXM instrument by observing the line width of the star-shaped target in the center of the test card.Experimental results show that the TXM instrument has an imaging field of view of 26μm and can achieve the clear imaging of characteristic structure with a line width of 30 nm.The radial power spectrum curve of the Siemens Star shows this TXM instrument has the potential to resolve 28.6-nm half pitch line pair features.Finally,we draw some conclusions and present outlook.At present,imaging of 30-nm-wide line features has been realized,but the imaging of 30-nm half pitch line pair feature has not yet been achieved,and the limit resolution has not reached the design value,either.We will continue to explore the potential for upgrading the imaging resolution of the laboratory TXM in future work.
作者
廖可梁
何其利
宋杨
李荣刚
宋茂华
李盼云
赵海峰
刘鹏
朱佩平
Liao Ke-Liang;He Qi-Li;Song Yang;Li Rong-Gang;Song Mao-Hua;Li Pan-Yun;Zhao Hai-Feng;Liu Peng;Zhu Pei-Ping(Ji’nan Key Laboratory of X-ray Optics,Ji’nan Hanjiang Opto-electronics Technology Ltd.,Ji’nan 250000,China;Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第17期66-74,共9页
Acta Physica Sinica
基金
山东省科技型中小企业创新能力提升工程(批准号:2023TSGC0093)
山东省企业技术创新项目(批准号:202350100372)
济南市海右人才工程(2022年度)资助的课题.
关键词
X
射线成像
X
射线显微镜
科学仪器
X-ray imaging
X-ray microscope
scientific instruments
