Nonthermionic hollow anode gas discharge electron beam source
AssigneeSFE Technologies
InventorMooyoung Ham
Life of this patent
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Abstract
Apparatus and method for producing a plurienergetic electron beam source. The apparatus includes a housing which functions as an anode, the same having an electron emission window covered by an electron-transparent grid, a cathode body mounted within the housing and electrically isolated therefrom, the spacing between the cathode body and grid being sufficient to permit a gas discharge to be maintained between them having a plasma region substantially thinner than the cathode sheath region. The method involves the simultaneous feeding of gas between a cathode body and an anode grid, applying voltages of about 10 kV to 20 kV and regulating the gas feed rate and the voltage to maintain a discharge condition of the character described above.
Claims18
A gas discharge electron beam source for use in a workspace evacuated and maintained at a pressure at least as low as about 10.sup.-3 torr, comprised of:
- a substantially closed housing made of electrically conductive material and having at least one port for the introduction of an ionizable gas into its interior, and also having at least one electron emission window;
- an electron extractor grid at least partially transparent to the passage of electrons and made of electrically conductive material mounted across the window and in electrical contact with the housing;
- a cathode body made of electrically conductive material mounted within the housing, but electrically isolated therefrom, and spaced apart from the housing in an opposed relationship with the grid, the space between the grid and the cathode body being chosen so as to permit a gas discharge having a cathode sheath region with a thickness greater than that of its plasma region to be maintained between them during operation and the space between the cathode body and the adjacent housing being too small for any appreciable discharge to take place between them during operation;
- and
- means for connecting a voltage source between the cathode and the housing, so that while the potential of the cathode is made about negative 10 kV with respect to the housing and grid and a sufficient amount of ionizable gas is present between the cathode and the grid, gas discharge occurs between them and free electrons thereby created are accelerated toward and pass through the grid and emission window in a continuous stream of plurienergetic electrons while substantially no gas ions are so emitted.
A method of generating a continous stream of plurienergetic electrons comprising the simultaneous steps of:
- introducing an ionizable gas between a cathode body and an electron-transparent anode in a vacuum at least as low as about 10.sup.-3 torr;
- impressing a negative voltage of about 10 kV on the cathode with respect to the anode;
- setting the distanoe between the cathode body and the anode;
- and
- regulating the gas pressure so as to maintain a gas discharge between the cathode and anode characterized by having a plasma region with a thickness less than the thickness of its cathode sheath region.
A method for curing monomer layers of dielectric materials without noticeable surface charging comprising the steps of:
- introducing an ionizable gas between a cathode body and an electron-transparent anode in a vacuum at least as low as about 10.sup.-3 torr;
- impressing a negative voltage on the cathode with respect to the anode;
- setting the distance between the cathode body and the anode;
- regulating the gas pressure so as to maintain a gas discharge between the cathode and anode characterized by having a plasma region with a thickness less than the thickness of its cathode sheath region;
- and
- exposing the monomer layers to be cured to the continuous stream of plurienergetic electrons generated by the preceding steps.
Dependencies are inferred from the claim text.