Electron Gun for Scalpel

A high current, high voltage and micro discharge free electron gun has been developed. This is a tetrode type electron gun, which has a rating of 120 keV, 1.6 mA. The advantages of this gun are: 1) a Ta single crystal cathode 1.5 mm in diameter; 2) lightweight and compact size electron gun for high rigidity; 3) micro-discharge free vacuum insulation techniques; 4) meshed grid Wehnelt for beam blanking and forming pulse circuits: 5) a compact and stable high voltage generator with CPU control and damping resistor employment. Details are as follows: A) A very flat Ta single crystal disk is welded precisely by laser beam on the tungsten wire. This cathode provides a very flat beam distribution at the target. B) Whole electrodes, such as a cathode, Wehnelt, 1st anode and grounded anode are mounted in the tube type ceramic insulator. The outside of this insulator is filled with pressurized SF6 gas in a pressure vessel made of aluminum. The compactness of the gun is achieved through this configuration.