透射电子显微镜单色器的发展及应用

自1932年透射电子显微镜发明以来,透射电子显微学在基础理论、仪器研制及其在材料科学、生命科学等领域的应用得到了迅速发展,200kV场发射枪透射电子显微镜的点分辨率已达0.19～0.25nm,能量分辨率为0.7～1.0eV。进一步提高透射电子显微镜性能的关键在于降低物镜球差和电子束能量扩散等。球差校正器的发明使透射电镜的点分辨率已突破0.1nm,电子源色差已成为进一步提高电子显微镜信息分辨极限和电子能量损失谱能量分辨率的瓶颈。在场发射枪透射电子显微镜上增加单色器（能量过滤器）可有效降低电子束的能量色散,减小色差对电子显微镜性能的影响。本文介绍了Wien型、Ω型及Mandoline型等几种常见的能量过滤器的工作原理、结构、性能及其应用。

Development and applications of monochromator in transmission electron microscope

With the rapid advances in science and technology, conventional transmission electron microscopes （TEM） with field emission gun operated at 200 kV has achieved point resolution of 0.19～0.25 nm and energy resolution of 0.7～1.0 eV. The resolution is confined by the spherical aberration of objective lens and energy spread of electron source. With the invention of spherical aberration corrector, point resolution of 0.1 nm （1 ） has been obtained. Therefore, the reduction of chromatic aberration becomes the most important factor to improve the information limit and energy resolution. Monochromator in TEM can effectively diminish energy spread of the incident electron beam, consequently reducing the limitation on TEM＇s performances by chromatic aberration. This paper introduced the principle, construction, performance and applications of several types of Monochromators including Wien type, Ω type and Mandoline type energy filters.