Ion-source neutralization with a hot-filament cathode-neutralizer

A method for providing a current-neutralized ion beam, the method comprising the steps of:

• (a) providing a gridded ion-source means capable of generating an ion beam and wherein said ion-source means includes an anode;
• (b) providing a beam-supply means having a positive terminal and a negative terminal, wherein said positive terminal of said beam-supply means is connected to said anode;
• (c) providing a hot-filament cathode-neutralizer;
• (d) providing a heater-supply means capable of generating a heater current, where said heater-supply means is connected to said cathode-neutralizer, and said heater current is sufficient to raise said cathode-neutralizer to an electron-emissive operating temperature beyond the emission threshold;
• (e) providing an electrical ground which may or may not be connected to earth ground;
• (f) connecting said cathode-neutralizer to a common circuit point with said negative terminal of said beam-supply means, wherein said circuit point is substantially isolated from said ground;
• (g) measuring the potential of said circuit point relative to said ground;
• and
• (h) controlling said heater current so as to maintain said potential of said circuit point within a predetermined range of values.

A method for providing a current-neutralized ion beam, the method comprising the steps of:

• (a) providing a gridded ion-source means capable of generating an ion beam and wherein said ion-source means includes an anode and an accelerator grid;
• (b) providing a beam-supply means having a positive terminal and a negative terminal, wherein said positive terminal of said beam-supply means is connected to said anode;
• (c) providing an accelerator-supply means having a positive terminal and a negative terminal, wherein said negative terminal of said accelerator-supply means is connected to said accelerator grid;
• (d) providing a hot-filament cathode-neutralizer;
• (e) providing a heater-supply means capable of generating a heater current, where said heater-supply means is connected to said cathode-neutralizer, and said heater current is sufficient to raise said cathode-neutralizer to an electron-emissive operating temperature beyond the emission threshold;
• (f) providing an electrical ground which may or may not be connected to earth ground;
• (g) connecting said cathode-neutralizer to a common circuit point with said negative terminal of said beam-supply means and said positive terminal of said accelerator-supply means, wherein said circuit point is substantially isolated from said ground;
• (h) measuring the potential of said circuit point relative to said ground;
• and
• (i) controlling said heater current so as to maintain said potential of said circuit point within a predetermined range of values.

Apparatus for providing a current-neutralized ion beam, said apparatus comprising:

• (a) gridless ion-source means capable of generating an ion beam, wherein said ion-source means includes an anode;
• (b) discharge-supply means having a positive terminal and a negative terminal, wherein said positive terminal is connected to said anode;
• (c) an electrical ground which may or may not be connected to earth ground;
• (d) hot-filament cathode-neutralizer means connected to a common circuit point with said negative terminal of said discharge-supply means, wherein said circuit point is substantially isolated from said ground;
• (e) Heater-supply means capable of generating a heater current, wherein heater-supply means is connected to said cathode cathode-neutralizer, and wherein said heater current is sufficient to raise said cathode-neutralizer to an electron-emissive operating temperature beyond the emission threshold;
• (f) means for measuring the potential of said circuit point relative to said ground;
• and
• (g) means for controlling said heater current so as to maintain said potential of said circuit point within a predetermined range of values.

Apparatus for providing a current-neutralized ion beam, said apparatus comprising:

• (a) gridded ion-source means capable of generating an ion beam, wherein said ion-source means includes an anode;
• (b) beam-supply means having a positive terminal and a negative terminal, wherein said positive terminal is connected to said anode;
• (c) an electrical ground which may or may not be connected to earth ground;
• (d) hot-filament cathode-neutralizer means connected to a common circuit point with said negative terminal of said beam-supply means, wherein said circuit point is substantially isolated from said ground;
• (e) Heater-supply means capable of generating a heater current, wherein heater-supply means is connected to said cathode cathode-neutralizer, and wherein said heater current is sufficient to raise said cathode-neutralizer to an electron-emissive operating temperature beyond the emission threshold;
• (f) means for measuring the potential of said circuit point relative to said ground;
• and
• (g) means for controlling said heater current so as to maintain said potential of said circuit point within a predetermined range of values.