DEVELOPMENT OF A NEW TECHNIQUE FOR MEASURING CHEMICAL FORM OF ELEMENTS IN NANOSCOPIC REGION USING PARTICLE BEAM ANALYSIS

在这项研究中，已经开发了一种纳米束系统，用于在纳米区域内的各种环境和生化条件下对样品进行化学态元素分析。结合PIXE、RBS和离轴STIM方法，实现了氢到金属元素的同时分析，揭示了样品中元素的化学成分。为了改善微束性能，将束斑尺寸减小到几十nm，同时提高束流，对Dynamitron加速器的终端设备和加速管进行了升级。对微束系统也进行了改进。来自碳化钨狭缝芯片和环形硅表面势垒探测器的寄生场污染将束斑尺寸限制在2×2μm^2。通过更换这些元件，减少了系统的寄生场污染，显著提高了微束系统的性能。在束流为μ的情况下，测得的束斑尺寸为0.4×0.4…m^2已经完成了更多的几十个帕。结果表明，在小电流条件下，该纳米束系统可获得小于0.4μm的束斑尺寸。黄沙尘颗粒的主要元素是硅、钙、氧、碳和氢，并以氧化物或碳酸盐的形式存在。铝、硅和钙的三元图显示了亚洲大陆和日本岛屿的土壤成分的差异。对于每个KOSA事件，钙和氯的相关性是不同的，这取决于到日本岛屿的运输的不同。黄沙尘颗粒含有更多的硫和更重的元素，如锰和锌。这些颗粒通过工业区从亚洲大陆输送到日本，并可能通过与人为气溶胶混合来吸附这些元素。这些结果是通过分析单个气溶胶颗粒获得的，而不是通过对多个颗粒进行平均测量的整体分析获得的。通过对黄沙粉尘的单颗粒分析，可以更好地了解其在运输过程中的形成过程。非波束系统也被用于钢材腐蚀的表征。在纳米区域可以确定腐蚀层的厚度和元素分布。当钢中铬含量低于0.1wt%时，腐蚀发生明显。较少

In this study, a nanobeam system has been developed for chemical state elemental analysis in samples under various environmental and biochemical conditions in the nanoscopic region. Combination of PIXE, RBS and off-axis STIM methods enabled simultaneous analysis for hydrogen to metal elements and revealed the chemical composition of the elements contained in the sample.In order to improve the microbeam performance and decrease the beam spot size down to several tens nm with higher beam current, the terminal equipments and an acceleration tube of the Dynamitron accelerator were upgraded. The microbeam system was also improved. Parasitic field contamination from tungsten carbide slit chips and an annular Si surface barrier detector limited the beam spot size to 2×2μm^2. By replacing these components, the parasitic field contamination of the system was reduced and the performance of the microbeam system was remarkably improved. A measured beam spot size of 0.4×0.4μm^2 at a beam current of … More several tens of pA has been accomplished. The results obtained using the grid-shadow method show that a beam spot size of less than 0.4μm is obtainable in the low-current regime.The nanobeam system was applied to analysis of yellow sand dust particles. The major elements of yellow sand dust particles are silicon, calcium, oxygen, carbon, and hydrogen, and exist in the form of oxide or carbonate. The ternary diagram of aluminum, silicon, and calcium shows the difference of the soil components of the Asian continent and Japanese islands. The correlation of calcium and chlorine is different for each Kosa event depending on the difference of transport to the Japanese islands. Yellow sand dust particles contain more sulfur and heavier elements such as manganese and zinc. These particles were transported from the Asian continent over industrial areas to Japan and might adsorb these elements by mixing with anthropogenic aerosols. These results were obtained by analyzing single aerosol particles and were not obtained using bulk analysis, which averages measurements over many particles. Single particle analysis of yellow sand dust will engender a better understanding of their formation process during transport.The nonobeam system was also applied to characterization of steel corrosion. Thickness and elemental distribution of corrosion layer could be determined in the nanoscopic region. Corrosion progresses remarkably in the case of steels containing Cr less than 0.1wt%. Less