IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0070032
(2005-02-28)
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등록번호 |
US-7423273
(2008-09-09)
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발명자
/ 주소 |
- Clayton,James E.
- Bjorkholm,Paul
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출원인 / 주소 |
- Varian Medical Systems Technologies, Inc.
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
12 인용 특허 :
42 |
초록
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In accordance with an embodiment, a method of examining contents of an object is disclosed comprising conducting a first examination of an object, checking for the presence of delayed neutrons if the first examination indicates that suspect material is present, and determining whether the object con
In accordance with an embodiment, a method of examining contents of an object is disclosed comprising conducting a first examination of an object, checking for the presence of delayed neutrons if the first examination indicates that suspect material is present, and determining whether the object contains nuclear material based, at least in part, on the check. The first examination may comprise a manual examination and scanning of the object to form an image, for example. The first examination may also comprise scanning of the object at two different radiation energies, calculating a function of the energy detected at the two radiation energies, and determining whether the object at least potentially contains suspect material based, at least in part, on the comparison. Systems are also disclosed.
대표청구항
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What is claimed is: 1. A method of examining contents of an object, the method comprising: conducting a first examination of an object; and conducting a second examination of the object if the first examination indicates that suspect material is present; the second examination comprising: scanning
What is claimed is: 1. A method of examining contents of an object, the method comprising: conducting a first examination of an object; and conducting a second examination of the object if the first examination indicates that suspect material is present; the second examination comprising: scanning at least a portion of the object with X-ray radiation; checking for the detection of delayed neutrons resulting from interaction of the X-ray radiation with contents of the object; and determining whether the object contains nuclear material based, at least in part, on the check for detection of delayed neutrons. 2. The method of claim 1, comprising: conducting the second examination only if the first examination indicates that suspect material is present. 3. The method of claim 1, wherein: the first examination comprises scanning at least a portion of the object with X-ray radiation. 4. The method of claim 3, wherein the first examination comprises: scanning the at least a portion of the object with radiation of at least 5.8 MeV, prior to checking for the detection of delayed neutrons. 5. The method of claim 4, wherein the second examination comprises: scanning the at least a portion of the object with second radiation of at least 13 MeV; checking for the detection of delayed neutrons; and determining whether the object contains nuclear material based, at least in part, on the second check for the detection of delayed neutrons. 6. The method of claim 3, wherein the first examination comprises: scanning the at least a portion of the object with radiation having a first energy; scanning the at least a portion of the object with radiation having a second energy of at least 5.8 MeV, the second energy being greater than the first energy; detecting radiation after scanning at the first energy; and detecting radiation after scanning at the second energy; and the second examination comprises: checking for the presence of delayed neutrons after scanning the at least a portion of the object at the second energy. 7. The method of claim 6, comprising: periodically scanning different portions of the object at the first and second energies, detecting radiation at the first and second scans, and checking for the detection of delayed neutrons. 8. The method of claim 6, further comprising: determining whether the object contains suspect material by: determining whether the object at least potentially contains material having an atomic number greater than the predetermined number based, at least in part, on the scanning of the at least a portion of the object at the first and second energies. 9. The method of claim 8, further comprising: calculating a function of the radiation detected at the first and second energies; and determining whether the object at least potentially contains material having an atomic number greater than the predetermined number based, at least in part, on the function. 10. The method of claim 8, further comprising: calculating a ratio of the radiation detected at the first and second energies; identifying a material within the object, based at least in part, on the ratio; and checking for the detection of delayed neutrons if the identified material is a suspect material. 11. The method of claim 3, wherein the scanning of the at least a portion of the object with X-ray radiation for the second examination and for the first examination are the same. 12. The method of claim 1, further comprising: identifying a nuclear material within the object based, at least in part, on the detection of delayed neutrons. 13. The method of claim 1, wherein the nuclear material is at least one of plutonium, uranium-233, uranium enriched in uranium-233, and uranium enriched in uranium-235. 14. The method of claim 1, wherein: the first examination comprises a manually examining the object. 15. The method of claim 1, wherein the first examination comprises: scanning the object; generating an image; and analyzing the image. 16. A method of examining contents of an object, the method comprising: determining whether an object at least potentially contains material having an atomic number greater than a predetermined number; and, if so, determining whether the object contains nuclear material by: scanning at least a portion of the object with X-ray radiation; and checking for the detection of delayed neutrons resulting from interaction of the X-ray radiation with contents of the object. 17. The method of claim 16, comprising: scanning the at least a portion of the object with X-ray radiation of at least 5.8 MeV; and checking for the detection of delayed neutrons resulting from interaction of the at least 5.8 MeV X-ray radiation with the at least a portion of the object. 18. The method of claim 16, further comprising: scanning first portions of the object with a first radiation beam at a first energy; detecting first radiation after interaction of the first radiation beam with the first portions, wherein projections of at least a portion of the first radiation beam through each portion, onto a detector, define respective first pixels; scanning second portions of the object with a second radiation beam at a second energy different than the first energy; detecting second radiation after interaction of the second radiation beam with the second portions, wherein projections of at least a portion of the second radiation beam through each portion, onto a detector, define respective second pixels; calculating first functions of the radiation detected at the first and second energies, for corresponding first and second pixels; grouping first functions of a plurality of corresponding pixels into at least one group; calculating a second function based on the first functions of at least certain of the plurality of pixels in each of the at least one group; and determining whether the object at least potentially contains material having a high atomic number greater than a predetermined atomic number, based, at least in part, on the second function of the at least one group. 19. The method of claim 18, further comprising: comparing the first functions to a criterion based, at least in part, on the predetermined atomic number prior to calculating the second function; wherein calculating the second function is based, at least in part, on the first functions meeting the criterion. 20. The method of claim 19, comprising: grouping first functions of corresponding pixels into at least one examination window having a predetermined size; calculating the second function by counting a number of first functions within the examination window that meet the criterion; and comparing the counted number to a predetermined number to determine whether the object at least potentially contains a high atomic number material. 21. The method of claim 20, wherein: the predetermined number is based, at least in part, on a predetermined false positive rate. 22. The method of claim 19, comprising: grouping first functions of contiguous corresponding pixels that meet the criterion into at least one group; calculating an area of the grouping; and comparing the area with a predetermined area to determine whether the object at least potentially contains a high atomic number material. 23. The method of claim 22, wherein the at least one group defines at least one matrix and the second function is an average, the method comprising: calculating an average of the first functions for the plurality of corresponding pixels within the at least one matrix; and comparing the average to the criterion to determine whether the object at least potentially contains a high atomic number material. 24. The method of claim 19, wherein comparing the first functions to the criterion comprises: comparing the first function to a threshold. 25. The method of claim 24, further comprising: calculating the threshold, at least in part, by: scanning at least a portion of a second object comprising material having an atomic number equal to the predetermined atomic number, with a third radiation beam at the first energy; detecting third radiation after interaction of the third radiation beam with the at least a portion of the second object; scanning at least a portion of the second object with a fourth radiation beam at the second energy; detecting fourth radiation after interaction of the fourth radiation beam with the at least a portion of the second object; and calculating the first function of the radiation detected at the third and fourth energies. 26. The method of claim 24, comprising: scanning at least a portion of a second object comprising a material having an atomic number less than an atomic number of lead. 27. A system for examining contents of an object, the system comprising: at least one X-ray radiation source; a first detector to detect radiation from the at least one X-ray source after interaction with at least a portion of the object; a second detector to detect delayed neutrons caused by interaction of radiation from the at least one X-ray source with the at least a portion of the object; at least one processor coupled to the first and second detectors, the at least one processor being programmed to: process data from the first detector to determine if the object at least potentially contains suspect material; and process data from the second detector to determine whether the object contains nuclear material. 28. A system for examining contents of an object, the system comprising: means for scanning at least a portion of an object at first and second X-ray radiation energies, wherein the first radiation energy is different than the second radiation energy; means for detecting radiation photons at the first and second radiations, after interaction with the object; means for detecting neutrons resulting from interaction of the X-ray radiation at at least one of the radiation energies with contents of the object; means for determining whether the object at least potentially contains material having an atomic number greater than a predetermined atomic number based, at least in part, on the radiation detected at the first and second energies by the first detector; and means for determining whether the object contains nuclear material based, at least in part, on data received from the means for detecting neutrons. 29. A method of examining contents of an object, the method comprising: manually examining contents of an object; and if the manual examination indicates that suspect material is present: scanning the object with X-ray radiation; checking for the detection of delayed neutrons; and determining whether the object contains nuclear material based, at least in part, on the check for detection of delayed neutrons. 30. A method of examining contents of an object, the method comprising: scanning at least a portion of an object with X-ray radiation; checking for the detection of delayed neutrons resulting from interaction of the X-ray radiation with contents of the object; and determining whether the object contains nuclear material based, at least in part, on the check for detection of delayed neutrons. 31. The method of claim 30, further comprising: detecting X-ray radiation interacting with the object; analyzing the detected radiation to identify suspect material; and checking for the detection of delayed neutrons resulting from interaction of the X-ray radiation with contents of the object, only if the detected X-ray radiation indicates that suspect material is present. 32. The method of claim 30, wherein checking for the detection of delayed neutrons comprises: scanning the at least a portion of the object with second radiation of at least 13 MeV; checking for the detection of delayed neutrons; and determining whether the object contains nuclear material based, at least in part, on the second check for the detection of delayed neutrons. 33. The method of claim 30, wherein the nuclear material is at least one of plutonium, uranium-233, uranium enriched in uranium-233, and uranium enriched in uranium-235.
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