Differential neutron spectrum generator and related methods and systems
A neutron spectrum generator is disclosed herein including a neutron source, a scatterer positioned in a direct path between the neutron source and a neutron detector, and a material shell configured to have at least one non-uniform characteristic selected from the group consisting of a material, a thickness, a length, an angle, a layer, and combinations thereof to generate a specific spectrum at the neutron detector that is different than the spectrum of the neutron source. A related method includes measuring a first response generated by a first material shell of a neutron spectrum generator interacting with a neutron source, replacing the first material shell with a second material shell, measuring a second response generated by a second material shell of a neutron spectrum generator interacting with the neutron source, and determining a total fission response by determining a difference between the first response and the second response.
1. A neutron spectrum generator, comprising:
a neutron source;
a scatterer positioned in a direct path between the neutron source and a neutron detector; and
at least one material shell positioned proximate the neutron source, and configured with at least one non-uniform characteristic selected from the group consisting of a material, a thickness, a length, an angle, a layer, and combinations thereof to generate a specific spectrum responsive to interacting with neutrons that is different than a spectrum of the neutron source.
2. The neutron spectrum generator of claim 1 , wherein the at least one material shell is a cylindrical shape.
3. The neutron spectrum generator of claim 1 , wherein the at least one material shell is a hemispheric shape.
4. The neutron spectrum generator of claim 1 , wherein the at least one material shell is a shape symmetric about its axis, wherein the axis is a vector extending from the neutron source through the scatterer to the neutron detector.
5. The neutron spectrum generator of claim 1 , wherein the at least one non-uniform characteristic of the material shell is divided according to angular wedges of the material shell.
6. The neutron spectrum generator of claim 1 , wherein the neutron source is a DT generator configured to produce neutrons by fusion of deuterium (D) and tritium (T).
7. The neutron spectrum generator of claim 1 , wherein the neutron source is a DD generator configured to produce neutrons by fusion of deuterium (D) and deuterium (D).
8. The neutron spectrum generator of claim 1 , wherein the neutron source is selected from the group consisting of a gamma source configured to eject a neutron, an electron accelerator beam, and a Bremsstrahlung converter.
9. The neutron spectrum generator of claim 1 , wherein the at least one material shell includes multiple material shells.
10. The neutron spectrum generator of claim 9 , wherein the multiple material shells are configured to generate the specific spectrum exhibiting multiple peaks.
11. The neutron spectrum generator of claim 1 , wherein the specific spectrum is an approximation of the spectrum for Californium-252, and the neutron source is a different source than Californium-252.
12. A method for generating a specific neutron spectrum, the method comprising:
measuring a first response generated responsive to a first material shell of a neutron spectrum generator interacting with a neutron source;
replacing the first material shell with a second material shell;
measuring a second response generated responsive to the second material shell of a neutron spectrum generator interacting with the neutron source; and
determining a total fission response by determining a difference between the first response and the second response.
13. The method of claim 12 , further comprising forming the first material shell and the second material shell to each have at least one non-uniform characteristic selected from the group consisting of a material, a thickness, a length, an angle, a layer, and combinations thereof to generate a specific spectrum at a neutron detector that is different than a spectrum of the neutron source.
14. The method of claim 13 , further comprising forming the first material shell and the second material shell to each have a cylindrical shape.
15. The method of claim 12 , further comprising forming the first material shell including uranium and the second material shell including lead.
16. The method of claim 12 , further comprising generating neutrons with the neutron source.
17. The method of claim 16 , wherein generating neutrons with the neutron source includes utilizing at least one of a DT generator, a DD generator, a gamma source configured to eject a neutron, an electron accelerator beam, or a Bremsstrahlung converter.
18. The method of claim 12 , wherein measuring the first response and the second response each include utilizing an active neutron detector.
19. The method of claim 12 , wherein measuring the first response and the second response each include utilizing a passive neutron detector.
20. The method of claim 12 , wherein measuring the first response and measuring the second response comprises measuring one of the first response and the second response as a positive response and the other of the first response and the second response as a negative response.