Space charge dosimeters for extremely low power measurements of radiation in shipping containers

• US 7,525,431 B2
• Filed: 05/06/2004
• Issued: 04/28/2009
• Est. Priority Date: 05/06/2004
• Status: Expired due to Fees

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: Hanson, Gregory R., Buckner, Mark A., Britton, Charles L. Jr., Bryan, William L.
• Primary Examiner(s): Lieu; Julie
• Application Number:
  US10/840,553
• Publication Number:
  US 20050248456A1
• Time in Patent Office: 1,818 Days
• Field of Search: None
• US Class Current: 340/572.1
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00
• CPC Class Codes: G08B 21/12 responsive to undesired emission of substances, e.g. pollution alarms
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Methods and apparatus are described for space charge dosimeters for extremely low power measurements of radiation in shipping containers. A method includes insitu polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, where the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out. Another method includes arranging a plurality of ionizing radiation sensors in a spatially dispersed array; determining a relative position of each of the plurality of ionizing radiation sensors to define a volume of interest; collecting ionizing radiation data from at least a subset of the plurality of ionizing radiation sensors; and triggering an alarm condition when a dose level of an ionizing radiation source is calculated to exceed a threshold.

Claims

1. A method, comprising insitu polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out, and wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor are powered only during reading-out dosimetric data.

2. The method of claim 1, wherein reading-out dosimetric data from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor includes reading-out to a communications circuit having a radio frequency transmitter that modulates a radio frequency signal as a function of dosimetric data read-out from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor.

5. A method of measuring ionizing radiation proximate a shipping container, comprising the method of claim 1.

3. A method, comprising insitu polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out, wherein reading-out dosimetric data from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor includes reading-out to a communications circuit having a radio frequency transmitter that modulates a radio frequency signal as a function of dosimetric data read-out from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor, and wherein the communications circuit is located within a radio frequency tag that transmits environmental state sensor data including dosimetric data read-out from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor.

4. The method of claim 3, wherein the radio frequency tag modulates the radio frequency signal using at least one modulation technique selected from the group consisting of hybrid spread spectrum, direct sequence spread spectrum, frequency hopping, time hopping, time division multiplexing, orthogonal frequency division multiplexing and infrared.

6. A method, comprising insitu polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out,

wherein i) dosimetric data from the first passive integrating ionizing radiation sensor is a function of a first filter having a first admittance and ii) dosimetric data from the second passive integrating ionizing radiation sensor is a function of a second filter having a second admittance that is substantially different from the first admittance.

7. A method, comprising:

insitu polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out; and

insitu temperature compensating of read-out dosimetric data from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor.

8. A method, comprising:

insitu polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out; and

insitu calibrating the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor.

9. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor; and

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit, and

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor are powered only during reading-out dosimetric data.

10. The apparatus of claim 9, wherein the communications circuit includes a radio frequency transmitter that modulates a radio frequency signal as a function of dosimetric data read-out from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor.

11. The apparatus of claim 9, wherein at a least one sensor selected from the group consisting of the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor includes a metal oxide silicon field effect transistor space charge dosimeter.

12. A shipping container, comprising the apparatus of claim 9.

13. A method, comprising:

arranging a plurality of ionizing radiation sensors in a spatially dispersed array;

determining a relative position of each of the plurality of ionizing radiation sensors to define a volume of interest;

collecting ionizing radiation data from at least a subset of the plurality of ionizing radiation sensors; and

triggering an alarm condition when a dose level of an ionizing radiation source is calculated to exceed a threshold.

14. The method of claim 13, wherein the spatially dispersed configuration defines an at least partially occupied array.

15. The method of claim 13, further comprising calculating a local statistical background ionizing radiation level.

16. The method of claim 13, further comprising calculating at least one surface characterizing a substantially constant ionizing radiation flux density to localize a position of the ionizing radiation source.

17. The method of claim 16, wherein calculating includes normalizing ionizing radiation data from at least one of the plurality of ionizing radiation sensors as a function of absorbing structure located within the volume of interest.

18. A method of monitoring shipping containers, comprising the method of claim 13.

19. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor; and

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit,

wherein the communications circuit includes a radio frequency transmitter that modulates a radio frequency signal as a function of dosimetric data read-out from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor, and

wherein the first passive integrating ionizing radiation sensor, the second passive integrating ionizing radiation sensor and the communications circuit define a radio frequency tag that transmits environmental stats sensor data as a function of dosimetric data read-out from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor.

20. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor; and

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit,

wherein the communications circuit includes a radio frequency transmitter that modulates a radio frequency signal as a function of dosimetric data read-out from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor, and

wherein the radio frequency tag modulates the radio frequency signal using at least one modulation technique selected from the group consisting of hybrid spread spectrum, direct sequence spread spectrum, frequency hopping, time hopping, time division multiplexing, orthogonal frequency division multiplexing and infrared.

21. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor; and

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit,

wherein the first passive integrating ionizing radiation sensor includes a first filter having a first admittance and the second passive integrating ionizing radiation sensor includes a second filter having a second admittance that is substantially different from the first admittance.

22. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor; and

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit,

wherein at a least one sensor selected from the group consisting of the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor includes an electret ion chamber space charge dosimeter.

23. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor; and

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit,

wherein at a least one sensor selected from the group consisting of the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor includes a microcantilever space charge dosimeter.

24. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor;

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor; and

a temperature compensation circuit coupled to the communications circuit, wherein the temperature compensation circuit insitu temperature compensates read-out dosimetric data from the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit.

25. An apparatus, comprising:

a first passive integrating ionizing radiation sensor;

a second passive integrating ionizing radiation sensor coupled to the first passive integrating ionizing radiation sensor;

a communications circuit coupled to the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor; and

a calibration circuit coupled to the communications circuit, wherein the calibration circuit insitu calibrates the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor,

wherein the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor read-out dosimetric data to the communications circuit.

26. An apparatus, comprising:

a plurality of ionizing radiation sensors arranged in a spatially dispersed configuration where a relative position of each of the plurality of sensors array is determined to define a volume of interest;

a data collection circuit coupled to the plurality of ionizing radiation sensors to collect ionizing radiation data from at least a subset of the plurality of ionizing radiation sensors; and

a computer coupled to the data collection circuit to i) calculate a dose level of an ionizing radiation source and compare the dose level to a threshold and ii) trigger an alarm when the dose level is equal to or greater than the threshold.

27. The apparatus of claim 26, wherein the spatially dispersed configuration defines an at least partially occupied array.

28. The apparatus of claim 26, wherein each of the plurality of ionizing radiation sensors includes a passive integrating ionizing radiation sensor.

29. A vehicle, comprising the apparatus of claim 26.

30. A method, comprising:

arranging a plurality of passive integrating ionizing radiation sensors in a spatially dispersed array;

determining a relative position of each of the plurality of passive integrating ionizing radiation sensors to define a volume of interest;

collecting ionizing radiation data from at least a subset of the plurality of passive integrating ionizing radiation sensors; and

triggering an alarm condition when collected ionizing radiation data from the subset of the plurality of passive integrating ionizing radiation sensors meets a predetermined spatial pattern criterion.

31. The method of claim 30, wherein the predetermined spatial pattern criterion includes a plurality of alternative patterns.

32. The method of claim 30, wherein the predetermined spatial pattern criterion includes a dosimetric data pattern defined by a function that includes a cube root of a radius from an approximate location of an ionizing radiation source.