EP0218240A2
Expired / Lapsed
EP
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Nitrogen detection
Assignee: Individual
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Filing: 1986-10-07
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Granted: —
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Expires: 2006-10-07
Abstract
Abstract A method and apparatus for detecting concentrations of nitrogen between 20% and 30% by weight such as is common in explosives is disclosed. A microtron having an output electron beam at a level below 45 MeV is targeted onto a typically tungsten target to provide gamma radiation levels. Deflection magnets adjacent to the target deflect the electron beam of the microtron to cause it to scan. Articles placed on a container containing suspect nitrogen are systematically scanned and output gamma radiation of 511 keV detected from nitrogen. Nitrogen concentrations and consequently expected concealed explosives are easily mapped in two or three dimensions, quantitatively.
Inventors
- 👤 Luis W. Alvarez
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 00:45
CPC Classifications
H; H05; H05H; H05H13/00; H05H13/10; G; G01; G01N; G01N23/00; G01N23/22; G01N23/221; G01V; G01V5/00; G01V5/20; G01V5/22; G01V5/234
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
80 words
Apparatus useful for the detection of nitrogen concentrations in an article comprising: a source of x-ray energy sufficient in frequency and energy to cause the following reaction 14 N (g amma , 2n ) 12 N but having insufficient energy to cause a significant reaction 16 O(gamma,n 3 H) 12 N; at least one gamma ray detector aligned near the path of said generated x-ray; and means for disposing said article between said x-ray source and said gamma ray detector.
Claim 2
Dependent Claim
80 words
Apparatus useful for the detection of nitrogen concentrations in an article comprising: a source of x-ray energy sufficient in frequency and energy to cause the following reaction 14 N (g amma , 2n ) 12 N but having insufficient energy to cause a significant reaction 16 O(gamma,n 3 H) 12 N; at least one gamma ray detector aligned near the path of said generated x-ray; and means for disposing said article between said x-ray source and said gamma ray detector.
Claim 3
Dependent Claim
19 words
The apparatus of claim 1 and wherein said means for disposing said article includes means for conveying said article.
Claim 4
Dependent Claim
17 words
The apparatus of claim 1 and including means for scanning said x-rays from said x-ray energy source.
Claim 5
Dependent Claim
124 words
4 . A method of scanning a series of conveyed articles for randomly placed nitrogen concentrations in the order of 20% to 30% by weight comprising the steps of: providing an x-ray source having x-rays in the range sufficient to cause a significant reaction 14 N (gamma, 2n ) 12 N but insufficient to cause a significant reaction 160(gamma,n3H)12N irradiating a suspect article to determine the presence of nitrogen with radiation sufficient to cause the reaction 14 N (gamma, 2n) 12 N where gamma is x-radiation, and n is a neutron; detecting delayed annihilation radiation in the range of 511 keV; and moving said article and beam relative to one another to quantitatively map said article in three dimensions, relative to its nitrogen content.
Claim 6
Dependent Claim
124 words
4 . A method of scanning a series of conveyed articles for randomly placed nitrogen concentrations in the order of 20% to 30% by weight comprising the steps of: providing an x-ray source having x-rays in the range sufficient to cause a significant reaction 14 N (gamma, 2n ) 12 N but insufficient to cause a significant reaction 160(gamma,n3H)12N irradiating a suspect article to determine the presence of nitrogen with radiation sufficient to cause the reaction 14 N (gamma, 2n) 12 N where gamma is x-radiation, and n is a neutron; detecting delayed annihilation radiation in the range of 511 keV; and moving said article and beam relative to one another to quantitatively map said article in three dimensions, relative to its nitrogen content.
Claim 7
Dependent Claim
14 words
The method of claim 4 and wherein said moving step includes conveying said article.
Claim 8
Dependent Claim
29 words
Method of claim 4 and wherein said mapping includes pulsating said x-radiation incident upon said article and examining said article for 11 milliseconds after each pulsation for said reaction.
Claim 9
Dependent Claim
107 words
Apparatus comprising in combination: a high energy electron source having an output electron beam in the order of 35 MeV; a target for said high energy electron source to produce x-radiation in the range between 0 and 40 MeV; deflection magnets adjacent said target for deflecting the electron beam of said microtron to cause said electron beam to scan; a conveyor; an article containing suspect nitrogen on said conveyor; and a stack of scintillation detectors for detecting annihilation gamma radiation produced by the reaction 14 N(gamma, 2n) 12 N where: gamma is x-radiation; n is a neutron; and 14 N and 12 N are isotopes of nitrogen.
Claim 10
Dependent Claim
107 words
Apparatus comprising in combination: a high energy electron source having an output electron beam in the order of 35 MeV; a target for said high energy electron source to produce x-radiation in the range between 0 and 40 MeV; deflection magnets adjacent said target for deflecting the electron beam of said microtron to cause said electron beam to scan; a conveyor; an article containing suspect nitrogen on said conveyor; and a stack of scintillation detectors for detecting annihilation gamma radiation produced by the reaction 14 N(gamma, 2n) 12 N where: gamma is x-radiation; n is a neutron; and 14 N and 12 N are isotopes of nitrogen.
Claim 11
Dependent Claim
26 words
The apparatus of claim 1 and wherein said source of x-rays is an electrom beam from a microtron or linear accelerator impacting a heavy element target.
Claim 12
Dependent Claim
138 words
9 . Apparatus useful for the tomographic mapping of nitrogen concentrations in an article comprising: a source of x-ray energy sufficient in frequency and energy to cause the following reaction 14 N (g amma , 2n ) 12 N but having insufficient energy to cause a significant reaction 16 O(gamma,n 3 H) 12 N; means for conveying along a conveyor path said article by said scanning x-ray beam; and, means for scanning said source of x-rays across said article and said conveyor path; first and second linear arrays of annihilation radiation detectors aligned parallel to the path of said generated x-rays, one array disposed on one side of a said conveyor path and the other array disposed on the opposite side of said conveyor path whereby a tomographic plot of the nitrogen in said articles can be made.
Claim 13
Dependent Claim
138 words
9 . Apparatus useful for the tomographic mapping of nitrogen concentrations in an article comprising: a source of x-ray energy sufficient in frequency and energy to cause the following reaction 14 N (g amma , 2n ) 12 N but having insufficient energy to cause a significant reaction 16 O(gamma,n 3 H) 12 N; means for conveying along a conveyor path said article by said scanning x-ray beam; and, means for scanning said source of x-rays across said article and said conveyor path; first and second linear arrays of annihilation radiation detectors aligned parallel to the path of said generated x-rays, one array disposed on one side of a said conveyor path and the other array disposed on the opposite side of said conveyor path whereby a tomographic plot of the nitrogen in said articles can be made.
Claim 14
Dependent Claim
18 words
10 . The apparatus of claim 9 and including means for discarding half life deteriorations in said radiation.
References Cited (Backward Citations)
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