Patent ID: 7183564

Claim:
A channel spark source for generating a stable focused electron beam comprising a coaxial arrangement of: a dielectric tube ( 7 ) in which a trigger plasma is generated, a hollow cathode ( 1 ) disposed axially adjacent the dielectric tube ( 7 ), a dielectric channel spark body ( 11 ) disposed with one end face adjacent the hollow cathode ( 1 ) and having an opposite end face disposed adjacent an anode ( 17 ) having a central passage, a dielectric end tube ( 5 ) extending from the anode and arranged in alignment with the dielectric channel spark body ( 11 ), a condenser connected as an electric energy storage between the anode ( 17 ) and the hollow cathode ( 1 ), an electrode ( 18 ) disposed at the end of the dielectric tube ( 7 ) remote from the hollow cathode ( 1 ) and extending into the trigger volume thereof, said electrode being connected to a reference potential by way of a spark discharge gap ( 19 ) and also to the hollow cathode ( 1 ) by way of electric resistor ( 20 ), a sleeve ( 21 ) extending into the hollow cathode ( 1 ) from the dielectric tube end thereof and having a central passage which widens conically toward the anode ( 17 ), said sleeve ( 21 ) forming part of the dielectric tube ( 1 ) and forming with the wall thereof an annular gap ( 13 ) which is closed at the end thereof adjacent the dielectric tube ( 7 ) and open at the end adjacent the channel spark body ( 11 ) and which ends in spaced relationship from the end of the hollow cathode ( 1 ) adjacent the anode ( 17 ) so that a rest volume with the inner diameter of the hollow cathode ( 1 ) remains in the hollow cathode ( 1 ) in communication with the hollow space, said hollow cathode ( 1 ) being provided with gas supply means for conducting a dosed amount of gas into the hollow cathode ( 1 ) in order to provide for a predetermined pressure differential between the hollow cathode exit and the dielectric tube exit, and a magnet disposed adjacent the dielectric tube ( 7 ) and having a magnetic field extending through the dielectric tube ( 7 ), said magnet being axially movable along the dielectric tube ( 7 ) and having a magnetic field axis which is pivotable relative to the axis of the dielectric tube ( 7 ).