Construction of 300 KV Electron Microscope and Its Electronmicroscopy

The three stage voltage supply and three stage electron gun for a 300 KV electron microscope are described. Each stage of the high voltage supply is operated at 100 KV with a ripple stability of about 1×10-4 and is connected to corresponding electrode of the gun. 300 KV is applied to the top electrode directly through an insulated cable whose exterior surface is kept at 200 KV so that 300 KV is not exposed to the air. The stability when operated at about 300 KV is within 4×10-4/min. The resolving power of the electron microscope measured at 300 KV is 20 Å. Transmissive powers of electron waves accelerated at 100 KV, 200 KV and 300 KV have been estimated for an aluminium single crystal from the contrast of the electron micrographs. Energy dependence of inelastic scattering in organic specimens is also shown. Electron micrographs of Mgo smoke crystals, stainless steel and polyoxy-methylene single crystals taken at 300 KV are presented.