CAS OpenIR  > 中科院上海应用物理研究所2004-2010年
Alternative TitleSTIM study in Shanghai scanning proton microprobe system
Thesis Advisor李燕
Degree Grantor中国科学院上海应用物理研究所
Place of Conferral上海应用物理研究所
Keyword扫描透射离子显微成像 核探针 计算机断层成像 元素分析 环境科学
Abstract扫描透射离子显微术(STIM)是上世纪八十年代出现的亚微米尺度的离子成像技术。其利用高能离子具有散射小、贯穿能力强,被探测效率高等特点对样品进行无损分析。可对较厚的样品做密度成像,具有亚微米的空间分辨率,由于使用fA级的束流,成像时间短,对样品的辐照损伤小。 由于STIM具有独到的特性,国际上一些核探针实验室相继开展了STIM技术的相关研究,使之成为微区成像的重要工具。本工作在上海应用物理研究所已有的性能良好的核探针装置上建立起国内第一个STIM的研究平台。 论文基于核探针装置建立了扫描透射离子显微成像系统。设计制作了匝数可调的马鞍形扫描线圈及遥控的线圈监控器,经测试,系统的扫描分辨率可达1um;为开展STIM-CT研究,安装了由步进电机驱动的六轴真空样品台,其平移精度为1μm,旋转精度为0.01°;设计组装了工作距离为130mm的长焦显微,图像解析度为1μm,在STIM-CT实验中可从靶室外部对样品进行观察定位。 针对STIM实验的数据特征,建立了基于中值方法的数据筛选程序以及面密度计算程序;参照X射线透射CT的卷积反投影算法,建立用于STIM-CT数据三维重构的计算机代码,并编写了可用于对PIXE-CT数据进行自吸收矫正的计算程序。仿真和实验数据的处理结果验证了该程序的正确性。 基于上述系统,开展了生物组织样品的面密度测量、大气颗粒物的元素分布信息分析、玻璃毛细管的STIM-CT研究等工作,并初步将STIM测得的面密度数据用于PIXE元素分布图的质量吸收矫正。这些工作测试了系统的性能指标,为进一步开展应用研究奠定了基础。
Other AbstractScanning Transmission Ion Microscopy (STIM) is a powerful sub-micro-scale imaging technology developed since the 1980s. It has spatial resolution in sub micrometer range and good sensitivity for using high-energy ions with small effect of scattering, deep penetration and high detected efficiency. STIM is used for mapping samples and areal mass density determination. Very low current beams (fA) is needed in STIM test, so samples should not suffer from irradiation. Because of these unique features of STIM, it has become an important micro-imaging tool. A number of international nuclear laboratories have launched the relevant STIM technical studies. It is necessary to build a STIM setup and develop STIM imaging methods in China. This work had been established the first STIM research platform based on the existing nuclear probe setup with good performance. A STIM setup was installed in the nuclear probe system, which includes a scanning coil system, a dedicated high-precision 6-axis manipulator works under high vacuum circumstance, and a long focal length microscopic observation system. A pair of saddle-shape air core coil can be controlled by a remote controlling system. The tests showed that the resolution of the nuclear probe is 1µm. The six-degree-of-freedom manipulator that driven by stepper moter is capable of providing very accurate position control with 1µm in translation and 0.01° in rotation. The microscopic observation system has a working distance of 133mm and a observation resolution of 1µm, which enables external observation of samples held in the target. A complete data-processing system had been accomplished for performing the STIM-CT experiment. Areal mass density calculation procedure and median filtering code were established. The 3D tomography reconstruction for STIM-CT was designed referring the convolution-projection algorithm of transmission X-ray CT. and Codes of self-absorption correction procedure for PIXE-CT was also designed. The results of both the simulation and experimental data processing verified the correctness of the data-processing system. Using the STIM setup and data-processing system, areal mass density of biological sample, element distribution of atmospheric particulate matter, and STIM-CT of glass capillary were achieved. Areal mass density from STIM experiment was preliminary applied to correct the mass absorption of the elements PIXE map. The results show that the STIM system runs well and carry out the design parameters.
Document Type学位论文
Recommended Citation
GB/T 7714
刘江峰. 扫描透射离子显微成像方法研究[D]. 上海应用物理研究所. 中国科学院上海应用物理研究所,2008.
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