Yirtual Source First Condenser Lens Condenser Aperture Second Condenser Lens Objective Aperture ☒☒ Scan Coils Objective Lens Scanning electron microscopy Sample Lanting Zhang School of Materials Science and Engineering. SJTU lantingzh@sjtu.edu.cn 1Scanning electron microscopy Lanting Zhang School of Materials Science and Engineering, SJTU lantingzh@sjtu.edu.cn 1