# US 2014/0151542 A1 · Detection of buried explosives

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- Number: US 2014/0151542 A1
- Document ID: US20140151542A1
- Status: Published application
- Kind: A1
- Application number: 13/901,120
- Filed: 2013-05-23
- Published: 2014-06-05
- Earliest claimed: 2009-04-23
- Assignees: Purdue Research Foundation
- Applicants: Purdue Research Foundation
- Inventors: David S. Koltick
- Web page: https://patentgrep.com/patent/US20140151542A1

## CPC

- G01V 5/234: {Measuring induced radiation, e.g. thermal neutron activation analysis}
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)

## Abstract

A system and method are described for capturing and analyzing gamma rays from neutron excitation of a region in 3-space being analyzed for explosives. A processor analyzes the results, determining whether underground explosives are present in a particular region of the ground. In one embodiment, one gamma ray energy band is used to infer an amount of silicon in the region, while another indicates the combined amount of silicon and nitrogen. The concentration of nitrogen in the region is inferred and used to trigger an “explosive found” or a “no explosive found” signal. In other embodiments, the system or method uses inferences about other elemental constituents of the ground being examined, sometimes taking as input analyses from prior scans, and providing output indicating the likelihood of the presence of explosives in the region.

## Claims

### Claim at position 1

-15. (canceled)

### Claim 16

A method of detecting explosives, comprising:
providing a neutron generator and a gamma ray detector;
detecting gamma radiation by the detector;
directing neutrons from the generator toward a material during a first period of time;
detecting gamma radiation from excitation of the material by the directed neutrons during a second period of time that ends one tenth of a second or less after the first period of time; and
quantifying the amount of detected radiation that varies with the amount of nitrogen in the material and the amount of detected radiation that varies with a substance other than nitrogen in the material.

### Claim 17 (depends on 16)

The system of claim 16, wherein said providing includes an electronic processor receiving a signal from the detector, and which further comprises preparing a sensitivity signal by the processor as a function of the amount of radiation corresponding to nitrogen and the amount of radiation corresponding to the substance; and
wherein the sensitivity signal quantifies the sensitivity of the processor to the presence of the substance.

### Claim 18 (depends on 16)

The system of claim 16, wherein said providing includes an electronic processor preparing an interference-level signal by the processor corresponding to the concentration of another substance, where the other substance emits radiation detected as varying with the amount of nitrogen and also radiation detected as varying with the amount of the substance.

### Claim 19 (depends on 16)

The system of claim 16, wherein said providing includes an electronic processor preparing a background-level signal by the processor that indicates the level of radiation detected in the absence of any radiation from particular elemental substances.

### Claim 20

A method of detecting explosives, comprising:
providing a neutron generator and a gamma ray detector;
emitting a pulse of neutrons by the neutron generator toward a region of interest;
receiving gamma radiation by the gamma ray detector from the region of interest;
preparing data corresponding to the received gamma radiation; and
applying a gain to the data, the gain varying in relation to neutron die-away during said receiving.

### Claim 21 (depends on 20)

The method of claim 20 which further comprises gating said receiving for a period of about one neutron die-away time constant.

### Claim 22 (depends on 20)

The method of claim 20 wherein said applying maintains the energy resolution of the detector substantially constant during the pulse.