Design and development of Thermionic Emission Microscope

Thermionic Emission Microscope (THEM) developed at CEERI has an electrostatic immersion lens to magnify the image. The geometry of lens and potentials are optimized to achieve a magnification of about 15 times with a clear image. The design of deflection plates and lens are carried out using OmniTRAK 3-D to ensure required deflection of beam without losing laminarity and beam interception with plates. Faraday cage, containing a narrow aperture, is designed to obtain elemental currents with low secondary emission. The emission picture of a B-Type cathode has been obtained. The results are satisfactory.