Patent Number: 
Section: claims

1. A low power neutron generator for subsurface use, comprising:a cathode configured to emit electrons to heat a grid configured to produce an ionizable gas when heated by the electrons impinging thereon and to cause emitted electrons to collide with ionizable gas atoms to generate ions; andan accelerating potential configured to accelerate the generated ions ontoa target configured to generate neutrons from a collision of ions impinging on the target. 2. The neutron generator of claim 1, wherein the grid is coated with a material that releases an ionizable gas when heated. 3. The neutron generator of claim 1, wherein the grid is positioned in a direct path to receive electrons emitted from the cathode. 4. The neutron generator of claim 1, wherein the cathode is configured to receive an adjustable current. 5. The neutron generator of claim 1, wherein the generator comprises a tube housing enclosing the grid, cathode, and target. 6. The neutron generator of claim 5, wherein the tube comprises a sealed envelope to contain ionizable gas released by the grid. 7. The neutron generator of claim 5, further comprising Deuterium or Tritium gas disposed within the tube. 8. A neutron generator for subsurface use, comprising:a tube forming a sealed envelope to contain a gas;a grid disposed within the tube to produce an ionizable gas when heated by electrons impinging thereon;a cathode disposed within the tube to emit electrons to heat the grid and cause emitted electrons to collide with ionizable gas atoms to generate ions; andan accelerating potential configured to accelerate the generated ions ontoa target disposed within the tube to generate neutrons from a collision of ions impinging on the target. 9. The neutron generator of claim 8, wherein the grid is coated with a material that releases an ionizable gas when heated. 10. The neutron generator of claim 8, wherein the grid is positioned in a direct path to receive electrons emitted from the cathode. 11. The neutron generator of claim 8, wherein the cathode is configured to receive an adjustable current. 12. The neutron generator of claim 8, wherein the tube comprises Deuterium or Tritium gas disposed therein. 13. A tool for subsurface use incorporating a neutron generator, the neutron generator comprising:a tube forming a sealed envelope configured to contain a gas;a grid disposed within the tube to produce an ionizable gas when heated by electrons impinging thereon;a cathode disposed within the tube to emit electrons configured to heat the grid and cause emitted electrons to collide with ionizable gas atoms to generate ions; andan accelerating potential configured to accelerate the generated ions ontoa target disposed within the tube to generate neutrons from a collision of ions impinging on the target. 14. The tool of claim 13, wherein the grid is coated with a material that releases an ionizable gas when heated. 15. The tool of claim 13, wherein the grid is positioned in a direct path to receive electrons emitted from the cathode. 16. The tool of claim 13, further comprising an adjustable current supply for the cathode. 17. The tool of claim 16, further comprising a voltage supply for electrical components of the generator. 18. The tool of claim 13, wherein the tube comprises Deuterium or Tritium gas disposed therein. 19. A method for constructing a neutron generator for subsurface use, comprising:disposing a cathode within a tube;disposing a grid within the tube to produce an ionizable gas when heated by electrons impinging thereon;configuring the cathode to emit electrons to strike the grid and to cause emitted electrons to collide with ionizable gas atoms to generate ions; anddisposing a target within the tube;applying an accelerating potential configured to accelerate the generated ions onto the target to generate neutrons from a collision of ions impinging on the target. 20. The method of claim 19, further comprising coating the grid with a material that releases an ionizable gas when heated. 21. The method of claim 19, further comprising positioning the grid in a direct path to receive electrons emitted from the cathode. 22. The method of claim 19, further comprising coupling an adjustable current supply to the cathode. 23. The method of claim 22, further comprising coupling a voltage supply for electrical components of the generator. 24. The method of claim 19, further comprising disposing Deuterium or Tritium gas within the tube. 25. A method for constructing a neutron generator for subsurface use, comprising:disposing a cathode within a tube configured for mounting on a tool for subsurface disposal, the tube forming a sealed envelope to contain a gas;disposing a grid within the tube to receive electrons emitted from the cathode, the grid configured to produce an ionizable gas when heated by electrons impinging thereon;configuring the cathode to emit electrons to collide with ionizable gas atoms to generate ions; anddisposing a target within the tube to generate neutrons from a collision of ions impinging on the target.