Electron-bombardment ion sources
AssigneeIon Tech Limited
InventorsPaul D. Reader, Harold R. Kaufman
Life of this patent
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Abstract
An electron-bombardment ion source includes a chamber into which a propellant is introduced. The propellant is ionized by means of electrons drawn toward an anode from a cathode. At one end of the chamber is an apertured screen followed by an aligned apertured grid. The grid is maintained at a potential that accelerates the ions out of the chamber through the screen and the grid and past a space-charge-neutralizing cathode. A resistor is connected between the grid and the neutralizing cathode in order to maintain the latter at a positive potential relative to the potential on the grid. A system ground preferably is connected to the junction between the resistor and the neutralizing cathode but, alternatively, may be connected between the grid and the resistor.
Claims14
An electron-bombardment ion source comprising:
- means defining a chamber for containing an ionizable propellant;
- means for introducing said propellant within said chamber;
- an anode disposed within said chamber;
- an electron-emissive cathode disposed within said chamber;
- means for impressing a potential between said cathode and said anode to effect electron emission at a sufficient velocity to ionize said propellant;
- an apertured grid disposed in the vicinity of one end of said chamber;
- power source means for impressing a potential between said grid and both said cathode and said anode for accelerating ions out of said chamber through said grid;
- neutralization means located beyond said grid from said chamber, for neutralizing the electric space charge in ions flowing beyond said grid;
- a system ground for said ion source;
- first direct-current conductive means for coupling said grid to said system ground;
- second direct-current conductive means for coupling said neutralizing means to said system ground;
- and a resistor included in series with one of said first and second conductive means for maintaining said neutralizing means at a positive potential relative to the potential on said grid.
An electron-bombardment ion source comprising:
- means defining a chamber for containing an ionizable propellant;
- means for introducing said propellant within said chamber;
- an anode disposed within said chamber;
- an electron-emissive cathode disposed within said chamber;
- means for impressing a potential between said cathode and said anode to effect electron emission at a sufficient velocity to ionize said propellant;
- an apertured grid disposed in the vicinity of one end of said chamber;
- power source means for impressing a potential between said grid and both said cathode and said anode for accelerating ions out of said chamber through said grid;
- neutralization means, located beyond said grid from said chamber, for neutralizing the electric space charge in ions flowing beyond said grid;
- and a resistor connected between said grid and said neutralizing means for maintaining said neutralizing means at a positive potential relative to the potential on said grid.
Dependencies are inferred from the claim text.