Deuterium tagged articles such as explosives and method for detection thereof

• US 4,251,726 A
• Filed: 02/26/1979
• Issued: 02/17/1981
• Est. Priority Date: 02/26/1979
• Status: Expired due to Term

• Current Assignee: Pharmacia & Upjohn Company (Pfizer Inc.)
• Original Assignee: Luis W. Alvarez
• Inventors: Alvarez, Luis W.
• Primary Examiner(s): Dixon, Harold A.
• Application Number:
  US06/015,499
• Time in Patent Office: 722 Days
• Field of Search: 250/302, 250/303, 250/358, 250/359, 250/499, 250/500
• US Class Current: 376/159
• CPC Class Codes: G01N 23/221 by activation analysis
• CPC Class Codes: G01V 5/20 Detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects
• CPC Class Codes: G01V 5/234 Measuring induced radiation, e.g. thermal neutron activation analysis
• CPC Class Codes: Y10S 149/123 Tagged compositions for identifying purposes

Abstract

Deuterium tagging in an amount at least ten (10) times the natural abundance of the deuterium isotope occurrence is disclosed. A composition of matter, including the group consisting of hydrogen containing compounds having at least one atom which is not oxygen and at least about ten (10) times the naturally occurring deuterium is disclosed. Preferred use is set forth in tagging explosives. A method of detecting the tagged article, such as explosives concealed in airline luggage includes subjecting tagged compounds with energy quanta sufficient to carry out the reaction

D→n+p-2.23 MeV

and detecting the number of neutrons generated is disclosed where n is a neutron, p is a proton and 2.23 MeV is the threshold energy required for the reaction. The apparatus, including a conveyor and a vertically scanning shutter is disclosed in combination with a linear accelerator for generating the X-ray energy in the order of 4 MeV and a boron triflouride proportional counter for detecting neutrons. Specific limitations are disclosed which readily adapt the method of tagged article detection to tagged explosives in airline luggage.

Claims

1. Apparatus useful for the detection of deuterium tagged articles comprising:

a source of X-ray photons sufficient in frequency and energy to cause the following reaction but having energy less than 4.14 MeV;

space="preserve" listing-type="equation">D→

n+p 2.23 MeV;

and a neutron detector embedded in a hydrogenous material aligned in the path of said generated neutrons to detect generated neutrons; and

means for conveying said article between said photon source and neutron detector.

2. The invention of claim 1 and including means for pulsating said photon source and means coupled to said detector for pulsating said detector and means cooperatively connected between said photon source and detector to turn off said detector during photon pulsations of said source.

3. The invention of claim 1 and including means for detecting X-ray absorption due to the atomic weight of said article scanned and means for determining Compton electron scattering of said X-rays from said photon source.

4. The invention of claim 1 and including means for dropping said photon source to about 2.2 MeV to detect abundant amounts of beryllium.

5. A method of scanning a series of conveyed articles for randomly placed deuterium tagged articles comprising the steps of:

an X-ray providing photon source scanning transversely through the conveyed path of said article having at least one neutron detector aligned to receive said emitted neutrons from the reaction;

space="preserve" listing-type="equation">D→

n+p-2.23 MeV

where p is a proton and n is a neutron;

said photon source and neutron detector going on opposite sides of said conveyed article path;

providing adjacent to said neutron detector means for generating said photons in side by side pixels;

pulsating said photon source with at least one pulsation for each said pixel and activating said detector to measure neutrons when photon source is not emitting said photons.

6. The method of claim 5 and including the steps of measuring Compton X-ray scattering while proton source is emitting said protons.

7. The method of claim 6 and including the steps of measuring X-ray absorption while said proton source is emitting protons.

8. A method of detecting a deuterium tagged article comprising the steps of exposing said article to pulses of energy quanta sufficient to carry out the following reaction but less than energy quanta of about 4.14 MeV:

space="preserve" listing-type="equation">D→

n+p-2.23 MeV; and

detecting the number of neutrons generated.

9. A method of tagging hydrogen-containing explosives comprising substituting deuterium for at least about 10 out of every 6900 hydrogen atoms.

10. A method for tagging non-hydrogen containing explosives comprising the step of adding deuterium.

11. A novel composition of matter selected from the group consisting of hydrogen containing compounds having at least one atom which is not oxygen and at least about 10 times the amount of naturally occurring deuterium and hydrogen and non-hydrogen containing compositions and mixtures thereof comprising deuterium.

12. The invention of claim 11 and wherein said composition of matter is explosive.

13. A novel composition of matter comprising hydrogen, oxygen and at least one other element, said hydrogen comprising at least about 10 times the naturally occurring amount of deuterium.

14. The invention of claim 13 and wherein said composition of matter is explosive.

15. A novel composition of matter comprising hydrogen and at least one element other than oxygen, said hydrogen comprising at least about 0.1449 percent more deuterium than would naturally be present.

16. The invention of claim 15 and wherein said composition of matter is explosive.

17. A novel composition of matter comprising hydrogen and at least one atom other than oxygen, said hydrogen comprising at least about 10 times the naturally occurring deuterium.

18. The invention of claim 17 and wherein said composition of matter is explosive.

19. A novel composition of matter comprising a hydrogen-containing explosive, said hydrogen comprising at least about 0.14 percent by weight deuterium.

20. Composition according to claim 19 wherein said explosive is a detonating cap and the deuterium about 0.28 percent by weight deuterium.