报告人： 米赵宏 博士， 新加坡国立大学
时间： 2016年10月26日上午9:30
地点：四川大学原子核科学技术研究所（720所）学术报告厅
报告题目及内容：
 

        Fast ion nano-probes that have energy of above 1 MeV are important in facilitating accelerator-based ion beam analysis and modification of materials at nanoscale accuracy, for example, high-resolution ion beam imaging of biological samples and lithography of materials at nanodimensions by proton beam writing.   Many research groups can routinely focus the ion beams down to micron or sub-micron spot sizes. However, for many years, it has been difficult in achieving beam spot sizes well below 100 nm.  Recently, we have witnessed the significant development of MeV ion beam focusing systems in reducing beam dimensions to 20 nm in the Centre for Ion Beam Applications (CIBA), National University of Singapore, such that ion beam applications that require sub-100 nm spatial resolutions is now possible.
        In this talk, the experimental instruments which mainly involve the magnetic quadrupole-lens based probe-forming system will be first introduced, followed by a detailed discussion of the requirements in achieving nano-probes. Our group in CIBA mainly focuses on the application of nano-probes in imaging single whole biological cells. As such, two high-resolution imaging modalities that utilize MeV highly focused ion beams are discussed: Scanning Transmission Ion Microscopy (STIM) which images the areal density of cells and gives an insight into the cellular structure, and Proton/Helium-ion Induced Fluorescence Microcopy (P/HeIFM) which images the fluorescence emission of fluorescent markers and probes used as labels within the cells. In addition, some other nano-probe applications including Proton Beam Writing (PBW) and on-going projects will be briefly discussed.