SYSTEMS AND METHODS FOR DETECTING CONCEALED NUCLEAR MATERIAL

• US 20120024044A1
• Filed: 02/05/2010
• Published: 02/02/2012
• Est. Priority Date: 02/05/2009
• Status: Active Grant

• Current Assignee: Temple University of The Commonwealth System of Higher Education, US Gov'T Represented By Secretary Of The Navy Chief Of Naval Research
• Original Assignee: Temple University of The Commonwealth System of Higher Education, Naval Research Laboratory (U.S. Department Of Defense)
• Inventors: Tao, Rongjia, Wu, Dong Ho
• Granted Patent: US 10,393,914 B2
• Time in Patent Office: Days
• US Class Current: 73/30.01
• CPC Class Codes: G01R 29/24 Arrangements for measuring quantities of charge
• CPC Class Codes: G01V 5/26 Passive interrogation, i.e. by measuring radiation emitted by objects or goods
• CPC Class Codes: G01V 5/281 detecting special nuclear material [SNM], e.g. Uranium-235, Uranium-233 or Plutonium-239

Abstract

Methods and systems for detecting nuclear material concealed within an enclosure are provided. An ionized air density is measured at one or more locations outside of the enclosure. The presence of the concealed nuclear material is detected, for each of the one or more locations, based on a characteristic of the measured ionized air density indicative of concealed nuclear materials.

Claims

1. A method for detecting nuclear material concealed within an enclosure comprising:

measuring an ionized air density at one or more locations outside of the enclosure; and

detecting the presence of the concealed nuclear material based on a characteristic of the measured ionized air density indicative of concealed nuclear materials, for each of the one or more locations.

2. A method according to claim 1, the method including, prior to measuring the ionized air density:

measuring a background ionized air density indicative of other sources of radiation in an environment outside of the enclosure,

wherein the background ionized air density is subtracted from the measured ionized air density during the detecting.

3. A method according to claim 1, wherein the detecting the presence of the concealed nuclear material based on the characteristic includes determining a positive air ion density and a negative air ion density from the measured ionized air density.

4. A method according to claim 3, further including:

distinguishing radiation generated by the concealed nuclear material from other sources of ionized air based on the positive air ion density and the negative air ion density.

5. A method according to claim 1, further including:

calculating a radiation dose from the characteristic of the measured ionized air density for each location.

6. A method according to claim 5, further including:

generating a spatial radiation dose map as a function of the one or more locations based on the calculated radiation dose for each location; and

displaying the spatial radiation dose map for determination of a location of the concealed nuclear material.

7. A method according to claim 1, wherein the detecting the presence of the concealed nuclear material includes:

detecting the presence of an air ion component from the measured ionized air density.

8. A method according to claim 7, wherein the air ion component includes at least one of nitrogen ions, oxygen ions, NO₃⁻

, HSO₄⁻

or H⁺(H₂O)_n.

9. A system for detecting nuclear material concealed within an enclosure comprising:

an ionized air sensor configured to measure an ionized air density at one or more locations outside of the enclosure; and

a concealed nuclear material detector configured to detect, for each of the one or more locations, the presence of the concealed nuclear material based on a characteristic of the measured ionized air density indicative of concealed nuclear materials.

10. A system according to claim 9, wherein the ionized air sensor includes an air-ion counter.

11. A system according to claim 9, wherein the ionized air sensor includes a terahertz spectrometer or a millimeter-wave spectrometer.

12. A system according to claim 9, wherein the concealed nuclear material detector comprises:

an air ion detector configured to detect, for each of the locations, a positive air ion density and a negative air ion density, the positive air ion density and the negative air ion density forming the characteristic; and

a radiation dose mapper configured to calculate a radiation dose, for each of the locations, from the respective detected positive air ion density and the negative air ion density.

13. A system according to claim 12, wherein the concealed nuclear material detector further comprises:

a false alarm detector configured to distinguish radiation generated by the concealed nuclear material from other sources of ionized air based on the positive air ion density and the negative air ion density.

14. A system according to claim 9, further comprising:

a sealed enclosure surrounding the ionized air sensor, the sealed enclosure configured to pass radiation generated by the concealed nuclear material and to block radiation from other sources of ionized air.

15. A system according to claim 14, wherein the blocked radiation includes alpha particles.

16. A system according to claim 14, wherein the other sources of ionized air include at least one of radon, lightning, a thunderstorm, or an electric discharge.