Optically powered charged particle accelerator

• US 5,049,753 A
• Filed: 06/28/1990
• Issued: 09/17/1991
• Est. Priority Date: 06/28/1990
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Flesner, Larry D.
• Primary Examiner(s): Berman, Jack I.
• Application Number:
  US07/549,885
• Time in Patent Office: 446 Days
• Field of Search: 250/396 R, 250/310, 250/311, 313/531, 328/233
• US Class Current: 250/396.00R
• CPC Class Codes: H01J 2201/342 Cathodes
• CPC Class Codes: H01J 2237/04735 with electrostatic means
• CPC Class Codes: H01J 27/00 Ion beam tubes H01J25/00, H01J33/00, H01J37/00 take precedence; particle accelerators H05H
• CPC Class Codes: H01J 3/021 Electron guns using a field emission, photo emission, or secondary emission electron source
• CPC Class Codes: H01J 37/073 Electron guns using field emission, photo emission, or secondary emission electron sources
• CPC Class Codes: H01J 37/248 Components associated with high voltage supply means for measuring the high voltage per se G01R15/00
• CPC Class Codes: H02J 50/30 using light, e.g. lasers
• CPC Class Codes: H05H 5/00 Direct voltage accelerators; Accelerators using single pulses H05H3/06 takes precedence

Abstract

A charged particle control apparatus provides very high voltage particle beams. One or more photocell arrays provide bias voltages for beam accelerating stages. The arrays are made from a number of microfabricated photocells connected in series to produce a voltage output that is the sum of the voltages from the individual cells. Arrays of each stage are connected in series to produce a cumulative stage voltage that is applied to an accelerating electrode made part of the stage.

These accelerating stages are disposed within a transparent vacuum chamber and are spaced from a charged particle source stage disposed near one end of the chamber. This charged particle source stage includes an emission source such as a photocathode. The photo arrays of the accelerating stages are connected in series to produce a potential that is applied to the particle source stage.

Optical power illuminates the stages to generate desired voltage biases to the accelerating electrodes. A light source is used to excite the photocathode when this emission source is used. Electrons from the emission source are accelerated by the accelerating electrodes and are emitted from the chamber which is typically conjoined with other apparatus.

By utilizing photocell arrays to generate beam current and accelerating biases, as well as a photocathode for providing a source of electrons, the apparatus of the invention is completely optically isolated thereby requiring no direct electrical connections to the apparatus even though multiple accelerating stages are used to facilitate the achievement of very high voltage particle beams.

Claims

1. A apparatus comprising:

means for emitting electrically charged particles into a vacuum; and

optically powered means for controlling said electrically charged particles.

2. An apparatus according to claim 1 in which said optically powered control means includes at least one microfabricated photocell array.

3. An apparatus according to claim 2 in which said charged particles include ions.

4. An apparatus according to claim 2 in which said charged particles include electrons.

5. An apparatus according to claim 4 in which said means for emitting electrically charged particles includes a photocathode.

6. A charged particle control apparatus comprising:

a vacuum chamber for providing a vacuum environment;

a source for emitting electrons into said vacuum environment; and

an optically powered means for accelerating said electrons.

7. An apparatus according to claim 6 in which said optically powered accelerating means includes microfabricated photocell arrays.

8. An apparatus according to claim 7 in which said source for emitting electrons includes a photocathode.

9. A charged particle control apparatus comprising:

a vacuum chamber for providing a vacuum environment;

a source for emitting electrons into said vacuum environment; and

an optically powered means for deflecting said electrons.

10. An apparatus according to claim 9 in which said optically powered deflecting means includes microfabricated photocell arrays.

11. An apparatus according to claim 10 in which said source for emitting electrons includes a photocathode.

12. A charged particle control apparatus comprising:

a vacuum chamber for providing a vacuum environment;

a source for emitting electrons into said vacuum environment; and

an optically powered means for focusing said electrons.

13. An apparatus according to claim 12 in which said optically powered focusing means includes microfabricated photocell arrays.

14. An apparatus according to claim 13 in which said source for emitting electrons includes a photocathode.

15. An electron accelerating apparatus comprising:

a source of optical power;

a photocathode, said photocathode providing an emission source of electrons when excited by said optical power; and

an optically powered accelerating means for accelerating said electrons, said optically powered accelerating means including

a plurality of accelerating stages, each stage including at least one photocell array and an accelerating electrode operably coupled to said photocell array, said at least one photocell array producing voltage when illuminated by said optical power with said voltage being applied to said accelerating electrode.

16. An apparatus according to claim 15 in which said at least one photocell array includes a plurality of microfabricated photocells.

17. An apparatus according to claim 15 in which said accelerating stages and said photocathode are operably connected.

18. An apparatus according to claim 17 in which said at least one photocell array includes a plurality of microfabricated photocells.