1. A neutron radiography system, comprising:
a first neutron source;
a first array of one or more alpha particle detectors configured to detect alpha particles associated with neutrons generated by the first neutron source;
a second neutron source;
a second array of one or more alpha particle detectors configured to detect alpha particles associated with neutrons generated by the second neutron source;
one or more neutron detectors positioned to detect at least some of the neutrons generated by the first neutron source and the second neutron source; and
an interrogation region located between the first neutron source, the second neutron source, and the one or more neutron detectors.
2. The neutron radiography system of claim 1, wherein the neutrons generated by the first neutron source and the neutrons generated by the second neutron source are uncollimated and form neutron cone beams.
3. The neutron radiography system of claim 1, wherein the neutrons from the first neutron source and the neutrons from the second neutron source are monoenergetic.
4. The neutron radiography system of claim 1, further comprising an image processing system coupled to the first array of one or more alpha particle detectors, the second array of one or more alpha particle detectors, and the one or more neutron detectors, the image processing system being configured to generate an image of an object positioned in the interrogation region, the generated image being based at least in part on the observed number of neutrons detected by the one or more neutron detectors relative to an expected number of neutrons detected by the one or more neutron detectors in the absence of the object.
5. The neutron radiography system of claim 1, further comprising an image processing system coupled to the first array of one or more alpha particle detectors, the second array of one or more alpha particle detectors, and the one or more neutron detectors, the image processing system being configured to generate an image of an object positioned in the interrogation region based at least in part a first projection image generated using detected neutrons from the first neutron source and a second projection image generated using detected neutrons from the second neutron source.
6. The neutron radiography system of claim 1, wherein an object is disposed in the interrogation region, and at least one of the first neutron source or the second neutron source are located adjacent to a corner of the object.
7. The neutron radiography system of claim 1, wherein the one or more neutron detectors are arranged in a ring shape.
8. The neutron radiography system of claim 1, wherein the one or more neutron detectors are at least partially arranged in a curved shape.
9. The neutron radiography system of claim 1, wherein the second neutron source is positioned between the first neutron source and the first array of one or more alpha particle detectors.
10. The neutron radiography system of claim 1, wherein the first neutron source is configured to emit a first neutron cone beam in a first orientation and the second neutron source is configured to emit a second cone beam in a second orientation, the first orientation being different than the second orientation.
11. The neutron radiography system of claim 10, wherein the second orientation is 90 degrees or substantially 90 degrees from the first orientation.
12. The neutron radiography system of claim 1, wherein at least one of the first neutron source or the second neutron source has a cone-beam angle of 45 degrees or greater.
13. The neutron radiography system of claim 1, further comprising one or more additional neutron sources.
14. The neutron radiography system of claim 1, wherein the neutron radiography system is part of an imaging system that includes a gamma-ray imaging system.
15. A method, comprising:
interrogating an object with a plurality of neutrons, a first portion of the neutrons being generated from a first neutron source and a second portion of the neutrons being generated from a second neutron source, at least some of the first portion and the second portion being generated during a same time period;
detecting one or more neutrons from the first portion and one or more neutrons from the second portion; and
generating an image of the object based at least in part on the detected neutrons from the first portion and the detected neutrons from the second portion.
16. The method of claim 15, wherein the first neutron source and the second neutron source are uncollimated.
17. The method of claim 15, wherein the first portion of neutrons is from a first cone beam of neutrons emitted from the first neutron source and the second portion of neutrons is from a second cone beam of neutrons emitted from the second neutron source, and wherein the first cone beam of neutrons and the second cone beam do not overlap at their respective origins.
18. The method of claim 15, wherein the generating the image of the object comprises:
generating projection images from the detected neutrons from the first portion and from the detected neutrons from the second portion, the projection images including a first projection image associated with the detected neutrons from the first portion and a second projection image associated with the detected neutrons from the second portion; and
reconstructing the image of the object using at least the first projection image and the second projection image.
19. The method of claim 18, wherein the reconstructing is performed using a maximum likelihood estimation maximization, ordered subset estimation maximization, filtered back projection, or iterative reconstruction technique.
20. A method, comprising:
generating a first neutron and a first associated particle at a first neutron source and a second neutron and a second associated particle at a second neutron source, the second neutron source being different than the first neutron source;
detecting the first associated particle at a first position on a first associated particle detector and the second associated particle at a second position on a second associated particle detector, the second associated particle detector being different than the first associated particle detector;
determining a first path of the first neutron through an interrogated object and a second path of the second neutron through the interrogated object, the determination of the first path of the first neutron being based on the first position at which the first associated particle is detected on the first associated particle detector, and the determination of the second path of the second neutron being based on the second position at which the second associated particle is detected on the second associated particle detector; and
detecting the first neutron at a first neutron detector and the second neutron at a second neutron detector.
21. The method of claim 20, wherein the first neutron detector and the second neutron detector are part of a single array of neutron detectors.
22. The method of claim 20, wherein the associated particle is an alpha particle, wherein the first associated particle detector is a first alpha particle detector, and wherein the second associated particle detector is a second alpha particle detector.
23. The method of claim 20, wherein the first neutron is detected at the first neutron detector simultaneously or substantially simultaneously as the second neutron is detected at the second neutron detector.
24. The method of claim 23, further comprising discriminating the first neutron from the second neutron based at least in part on the determination of the first path of the first neutron and the determination of the second path of the second neutron.
25. The method of claim 20, further comprising generating a first projection image using in part the detection of the first neutron and generating a second projection image using in part the detection of the second neutron, the second projection image being different than the first detection image.
26. The method of claim 20, wherein the first neutron source and the second neutron source are operated simultaneously to generate neutrons during a common time period.
27. One or more computer-readable media storing computer-executable instructions which when executed by a computer cause the computer to perform a method, the method comprising:
receiving data from two or more alpha particle detectors, including data from a first alpha particle detector indicating times at which a first set of alpha particles are detected by the first alpha particle detector and data from a second alpha particle detector indicating times at which a second set of alpha particles are detected by the second alpha particle detector, wherein the first set of alpha particles are associated with a first set of neutrons generated by a first neutron source, and wherein the second set of alpha particles are associated with a second set of neutrons generated by a second neutron source;
receiving data from one or more neutron detectors indicating times at which neutrons are detected by the one or more neutron detectors; and
identifying the neutrons detected by the one or more neutron detectors as being either neutrons emitted from the first neutron source or neutrons emitted from the second neutron source based at least in part on the data from the first alpha particle detector and the data from the second alpha particle detector.
28. The one or more computer-readable media of claim 27, wherein the method further comprises generating projection images based at least in part on the data from the two or more associated particle detectors and the data from the one or more neutron detectors, the projection images including a first projection image based on neutrons detected at the one or more neutron detectors and identified as being from the first set of neutrons emitted from the first neutron source and a second projection image based on neutrons detected at the one or more neutron detectors and identified as being from the second set of neutrons emitted from the second neutron source.
29. The one or more computer-readable media of claim 28, wherein the method further comprises generating a three-dimensional image of the object from at least the first projection image and the second projection image.
30. The one or more computer-readable media of claim 27, wherein the data from the first alpha particle detector further indicates positions on the first alpha particle detector at which the first set of alpha particles are detected,
wherein the data from the second alpha particle detector further indicates positions on the second alpha particle detector at which the second set of alpha particles are detected, and
wherein the method further comprises identifying two neutrons simultaneously detected during a same sampling period by the one or more neutron detectors as being a neutron emitted from the first neutron source and a neutron emitted from the second neutron source based at least in part on the data from the first alpha particle detector and the data from the second alpha particle detector.
31. The one or more computer-readable media of claim 27, wherein the first set of neutrons and the second set of neutrons are generated at least partially during a same time period.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What we claim is:
1. An apparatus comprising:
a passageway; and
at least one rotor (4) having a surface shaped to drive a media (2) in an intermittent fashion.
2. The apparatus of claim 1 wherein the intermittent drive is achieved by intermittent contact of the surface with the media.
3. The apparatus of claim 1 wherein the surface of the rotor is generally circular and wherein intermittent drive is achieved by operating the rotor in an intermittent manner.
4. The apparatus of claim 1 further comprising:
a plurality of rotors (4, 8) that contact the media (2) in an intermittent fashion; and
a drive apparatus for maintaining the rotors in a phase angle relationship.
5. The apparatus of claim 4 wherein the rotors have alternate geometric forms.
6. The apparatus of claim 5 wherein the geometric forms comprise at least one of a semicircle, an ellipsoid, a trilobular, a multifacial polygon, and a cruciform.
7. The apparatus of claim 4 where the contact surfaces of the rotors are of generally circular form and the intermittent drive is obtained by operating the rotors or nip rollers (6, 9) in an intermittent manner.
8. The apparatus of claim 4 wherein the rotors are substantially circular and the intermittent drive is obtained by providing an outer surface (42) with at least one high friction surface (23) and at least one low friction surface (24).
9. The apparatus of claim 1 wherein the rotor has a variable geometry capable of presenting a continuous drive surface or an intermittent drive surface.
10. The apparatus of claim 9 wherein the intermittent drive surface is used to transport the media into the apparatus, and the continuous drive surface is used to drive the media out of the apparatus.
11. An apparatus comprising:
a passageway; and
at least one rotor (4) having a contact surface shaped to drive a media (2) in an intermittent fashion, wherein the rotor surface is generally circular and the intermittent drive is obtained by modulating the contact pressure.
12. The apparatus of claim 11 further comprising a plurality of rotors having contact surfaces of generally circular form, wherein the intermittent drive is obtained by modulating the contact pressure at each rotor to have a phase relationship such that substantially one rotor drives the media at any one time.
13. The apparatus of claim 12 wherein the rotors have different geometric forms.
14. The apparatus of claim 13 wherein the geometric forms comprise at least one of a semicircle, an ellipsoid, a trilobular, a multi-facial polygon and a cruciform.
15. The apparatus of claim 11 wherein the rotor has a variable geometry capable of presenting a continuous drive surface or an intermittent drive surface.
16. The apparatus of claim 15 wherein the intermittent drive surface is used to transport the media into the apparatus, and the continuous drive surface is used to drive the media out of the apparatus.
17. An apparatus comprising:
a passageway;
at least one rotor (4) having a continuous and substantially circular contact surface including at least one high friction region (23) and at least one low friction region (24) arranged to drive a media (2) in an intermittent fashion.
18. The apparatus of claim 17 wherein an enhanced intermittent drive may be obtained by modulating the normal contact pressure of the rotor contact surface with the media.
19. The apparatus of claim 17 wherein a rotor has a variable geometry capable of presenting a continuous drive surface or an intermittent drive surface.
20. The apparatus of claim 19 wherein the intermittent drive surface is used to transport the media into the apparatus, and the continuous drive surface is used to drive the media out of the apparatus.
21. A method of aligning media comprising:
driving media into a media passageway; and
allowing the media to rotate about one or more fixed centers of at least one rotor as the media contacts at least one side wall of the media passageway.
22. A method of producing a lateral shift in the location of a media comprising:
driving media into a media passageway; and
shifting the media via a combination of rotations about a plurality of intermittent centers.
23. A method for continuously driving media comprising:
driving the media into a passageway having a plurality of rotors; and
transporting the media with drive rotors having surfaces arranged to have intermittent degrees of contact with the media.
24. A method of aligning media comprising:
releasing stored strain energy in a flexible media using an intermittent drive system; and
allowing the media to slide against at least one side wall.
25. A method of transporting flexible media in a media transport system comprising:
driving the flexible media into a passageway using an intermittent drive system; and
permitting stored strain energy of the flexible media to be released such that the media aligns itself during transport.