Cylindrical neutron generator

• US 7,639,770 B2
• Filed: 04/22/2008
• Issued: 12/29/2009
• Est. Priority Date: 04/22/2008
• Status: Active Grant

• Current Assignee: Ernest Orlando Lawrence Berkeley National Laboratory, Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Leung, Ka-Ngo
• Primary Examiner(s): MONDT, JOHANNES P
• Assistant Examiner(s): Dudnikov; Vadim
• Application Number:
  US12/107,545
• Publication Number:
  US 20090262881A1
• Time in Patent Office: 616 Days
• Field of Search: None
• US Class Current: 376/159
• CPC Class Codes: H05H 3/06 Generating neutron beams targets for producing nuclear reactions H05H6/00; neutron sources G21G4/02
• CPC Class Codes: Y02E 30/10 Nuclear fusion reactors

Abstract

A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360° and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

Claims

1. A cylindrical neutron source, comprising:

a cylindrical chamber;

a plurality of alternatingly nested concentric or coaxial neutron generating targets and plasma ion generating regions, wherein each target is a cylinder and each plasma ion generating region is annular and has an inner and an outer plasma boundary surface;

an RF antenna induction coil positioned in each plasma ion generating region;

cylindrical extraction electrodes at both the inner and outer boundary surfaces of each plasma ion generating region having a voltage difference applied relative to the adjacent target, the extraction electrodes containing a plurality of longitudinal slots through which the ions are extracted from plasma ion generating regions and directed onto the targets in consequence of the applied voltage.

2. The neutron source of claim 1 wherein the plasma generating regions are deuterium ion sources.

3. The neutron source of claim 2 wherein the targets have titanium surfaces.

4. The neutron source of claim 1 wherein the source has a length of about 35 cm and a diameter of about 50 cm.

5. A cylindrical neutron source, comprising:

a cylindrical chamber;

at least two plasma ion generating regions and at least two neutron generating targets, a first neutron generating target disposed concentrically as a cylinder inside and spaced from a first plasma ion generating region, a second neutron generating target disposed concentrically as a cylinder outside and spaced from said first plasma ion generating region, and a second plasma ion generating region disposed concentrically outside and spaced from said second neutron generating target, all of said plasma generating regions and said neutron generating targets being disposed within said cylindrical chamber;

an RF antenna induction coil disposed within each plasma generating region; and

a plurality of cylindrically shaped extraction electrodes having longitudinal slots, wherein each said plasma ion generating region is annular and has an inner and an outer plasma boundary surface, each of said plasma ion generating regions having a first extraction electrode disposed adjacent said inner plasma boundary surface of said plasma ion generating regions, each of said inner plasma boundary surfaces being disposed in each of said plasma ion generating regions so as to be positioned within a portion of said plasma ion generating region that is located toward a center longitudinal axis of said neutron source, and a second extraction electrode disposed adjacent said outer plasma boundary surface of said plasma ion generating region, each of said outer plasma boundary surfaces being disposed in each of said plasma ion generating regions so as to be positioned within a portion of said plasma ion generating region that is located farther from the center longitudinal axis than is said inner plasma boundary surface, and each said first and second extraction electrodes having a voltage difference applied relative to the adjacent target.

6. The cylindrical neutron source of claim 5 wherein the plasma generating regions are deuterium ion sources.

7. The cylindrical neutron source of claim 6 wherein the targets have titanium surfaces.

8. The cylindrical neutron source of claim 5 wherein the source has a length of about 35 cm and a diameter of about 50 cm.

9. The cylindrical neutron source of claim 5 further comprising a plurality of coaxially nested alternating ion sources and targets.

10. The cylinder neutron source of claim 5, wherein each plasma generating region forms an unintermittent plasma.