Bolzenkathode als Objekt im Elektronen-Emissionsmikroskop

Summary Experiences are reported in connection with the use of bolt cathode as the object-holder in an electron emission microscope. The bolt cathode consists of a cylindrical Tungsten rod, the bolt, close pinched at one end, the top of the other free end being used as the emission surface. The bolt is surrounded by a Tungsten helix, which can be heated by passing direct current. This helix serves as a primary cathode emitting electrons for electron bombardment of the bolt. In the case of use of bolt cathode as specimen holder in an electron emission microscope the specimen is melted on the top of the Tungsten bolt. Melting occurs by the bombardment of specimen substances with accelerated electrons from an electron gun. This method has many advantages and is described in detail. Two properties of the bolt cathode, important for the emission microscope, i. e. the axial displacement of the object and the magnetic field of the heating helix, are discussed in detail. A micrograph shows the quality of the electron emission pictures obtained.