Tamper-proof container

• US 20050151068A1
• Filed: 11/05/2004
• Published: 07/14/2005
• Est. Priority Date: 01/09/2004
• Status: Active Grant

• Current Assignee: 3-D Image Technology
• Original Assignee: Tamperproof Container Licensing Corp.
• Inventors: Beinhocker, Gilbert D.
• Granted Patent: US 7,211,783 B2
• Time in Patent Office: Days
• US Class Current: 250/227.150
• CPC Class Codes: G01J 1/0425 using optical fibers
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G08B 13/126 for a housing, e.g. a box, a safe, or a room

Abstract

A sheet includes an optical fiber extending across at least a portion of its surface to detect nuclear radiation. The sheet can line at least a portion of a shipping container or box. Radiation within or outside the container or box reduces optical transmissibility of the fiber. The fiber integrates the radiation over time and/or over the length of the fiber, making the fiber sensitive to even low-level radiation. Dopants, use of particular wavelengths of light or temperatures or other mechanisms can increase the sensitivity of the optical fiber to radiation. The optical fiber is monitored for a change in its transmissibility. A reduction in the transmissibility, such as to below a threshold, can trigger an alarm, such as an annunciator, or send a message that includes information about the time or the container'"'"'s contents or location when the radiation is detected to a central location, such as a ship'"'"'s control room or port notification system.

Claims

1. A radiation detection system comprising:

at least one panel having an area and having an optical fiber extending across at least a portion of the area, such that nuclear radiation impinging on the optical fiber causes a decrease in light-carrying capacity of the optical fiber;

a light source configured to produce light having a wavelength less than or equal to about 980 nm optically connected to one end of the optical fiber;

a light detector optically connected to another end of the optical fiber; and

a circuit connected to the light detector and configured to detect the decrease in light-carrying capacity of the optical fiber.

2. The radiation detection system of claim 1, wherein the light source is configured to produce light having a wavelength less than or equal to about 600 nm.

3. The radiation detection system of claim 1, wherein the light source is configured to produce light having a wavelength less than or equal to about 540 nm.

4. The radiation detection system of claim 1, wherein the light source is configured to produce light having a wavelength less than or equal to about 502 nm.

5. The radiation detection system of claim 1, wherein the light source is configured to produce light having a wavelength less than or equal to about 472 nm.

6. A radiation detection system comprising:

at least one panel having an area and having an optical fiber extending across at least a portion of the area, such that nuclear radiation impinging on the optical fiber causes a decrease in light-carrying capacity of the optical fiber;

a light source configured to produce light having at least a short-wavelength component and a long-wavelength component optically coupled to a first end of the optical fiber;

a first light detector optically connected to a second end of the optical fiber and configured to receive one of the wavelength components without receiving the other wavelength component;

a second light detector optically connected to the second end of the optical fiber;

a difference circuit connected to the first and second light detectors and configured to detect a difference between the intensity of the received short-wavelength component and the received long-wavelength component.

7. The radiation detection system of claim 6, wherein the second light detector is configured to receive the other wavelength component without receiving the wavelength component received by the first light detector.

8. A radiation detection system comprising:

at least one panel having an area and having an optical fiber extending across at least a portion of the area, such that nuclear radiation impinging on the optical fiber causes a decrease in light-carrying capacity of the optical fiber, wherein the optical fiber includes a dopant that increases sensitivity of the optical fiber to decrease the light-carrying capacity as a result of the nuclear radiation impinging thereon;

a light source optically connected to one end of the optical fiber;

a light detector optically connected to another end of the optical fiber; and

a circuit connected to the light detector and configured to detect the decrease in light-carrying capacity of the optical fiber.

9. The radiation detection system of claim 8, wherein the dopant is at least one of erbium, ytterbium, aluminum, phosphorus, germanium and lanthanum.

10. The radiation detection system of claim 8, wherein the optical fiber includes about 0.18 mol % Yb, about 4.2 mole percent Al₂O₃ and about 0.9 mol % P₂O₅.

11. The radiation detection system of claim 8, wherein the optical fiber includes about 2.0 mol % La and about 6.0 mol % Al₂O₃.

12. The radiation detection system of claim 8, wherein the optical fiber includes no fluorine in its core.

13. A radiation detection system comprising:

at least one panel having an area and having an optical fiber extending across at least a portion of the area, such that nuclear radiation impinging on the optical fiber causes a decrease in light-carrying capacity of the optical fiber, wherein the optical fiber includes a dopant that increases an index of refraction of a core of the optical fiber;

a light source optically connected to one end of the optical fiber;

a light detector optically connected to another end of the optical fiber; and

a circuit connected to the light detector and configured to detect the decrease in light-carrying capacity of the optical fiber.

14. The radiation detection system of claim 13, wherein the dopant is phosphorus.

15. A method of detecting nuclear radiation, comprising:

disposing at least one optical fiber proximate to a shipping container;

illuminating one end of the optical fiber;

exposing the optical fiber to the nuclear radiation for at least one day, thereby integrating the effect of the nuclear radiation on the optical fiber over time; and

monitoring the illumination at the other end of the optical fiber.

16. The method of claim 15, further comprising:

detecting a reduction in the transmissibility of the optical fiber.

17. The method of claim 16, further comprising:

responsive to detecting the reduction in the transmissibility of the optical fiber, activating an alarm.

18. The method of claim 15, wherein the exposing the optical fiber to the nuclear radiation comprises exposing the optical fiber to nuclear radiation from within the shipping container.

19. The method of claim 15, wherein the exposing the optical fiber to the nuclear radiation comprises exposing the optical fiber to nuclear radiation from outside the shipping container.

20. The method of claim 15, wherein the disposing the optical fiber comprises disposing at least 1 km of optical fiber proximate to the shipping container.

21. The method of claim 15, wherein the disposing the optical fiber comprises disposing the optical fiber within the shipping container.

22. A method of detecting nuclear radiation, comprising:

disposing an optical fiber proximate to each of a plurality of shipping containers and associating each optical fiber with the respective shipping container;

illuminating one end of each of the optical fibers;

monitoring the illumination at the other end of each of the optical fibers;

detecting a reduction in a transmissibility of at least some of the optical fibers;

identifying two or more shipping containers respectively associated with at least some of the optical fibers in which the reductions in transmissibility are detected;

using information about geometric placement of the identified shipping containers to identify a location of the nuclear radiation.