Abstract
A new computer controlled 120kV high performance TEM has been developed(Fig. 1). The image formation system of the microscope enables us to observe high resolution, wide field,and high contrast without replacing the objective lens pole-piece. The objective lens is designed for high- contrast (HC) and high-resolution(HR) modes, and consists of a double gap and two coils. A schematic drawing of the objective lens and the strength of the magnetic field of the lens is described in Fig.2. When the objective lens is used in HC mode, upper and lower coils are operated at a lens current of same polarity to form the long focal length. The focal length(fo), spherical aberration coefficient(Cs) and chromatic aberration coefficient (Cc) in HC mode at 100kV are 6.5, 3.4 and 3.1mm, respectively. Magnification range at HC mode is × 700 to × 200,000. The viewing area with an objective aperture of a diameter of 10μm is 160mm in diameter. In HR mode, the polarity of lower coil current is reversed to form a shorter focal length for high resolution image observation. The fo, Cs and Cc of the objective lens in HR mode at lOOkV are 3.1, 2.8 and 2.3mm, respectively. The highest magnification in HR mode is × 600,000.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Proceedings, annual meeting, Electron Microscopy Society of America
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
