CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a U.S. National Stage to International Application No. PCT/CN2019/088919, filed on May 29, 2019, which based on and claims the benefit of priority to the Chinese patent application No. 201810755428.5, filed on Jul. 11, 2018, the content of each of which is hereby incorporated by reference in its entirety into the present application.

TECHNICAL FIELD

The present disclosure relates to the field of radiation detection technology, and particular to a dual mode detection method, controller and system.

BACKGROUND

Transmission imaging using X-rays generated by an electron accelerator is a conventional technique for obtaining mass thickness information of a substance to be detected, but such technique is not suitable for material identification. In order to improve the capability of material identification, or even to analyze isotope information, it is necessary to utilize two or more types of radiation.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of some embodiments of the present disclosure, a dual mode detection method is provided, comprising: determining a ratio of neutron to X-ray differential cross sections of an inspected object, according to X-ray object detection data, X-ray object-free detection data, neutron object detection data, and neutron object-free detection data; determining a substance type of the inspected object according to a correspondence between the ratio of neutron to X-ray differential cross sections of the inspected object and the substance type.

In some embodiments, when the inspected object is placed between a first detection port of the dual mode detection device and an X-ray detector, obtaining the X-ray object detection data according to a detection result of the X-ray detector, and obtaining the neutron object-free detection data according to a detection result of a neutron detector; when the inspected object is placed between a second detection port of the dual mode detection device and the neutron detector, obtaining the X-ray object-free detection data according to a detection result of the X-ray detector, and obtaining the neutron object detection data according to a detection result of the neutron detector; wherein, the first detection port emits X-rays, and the second detection port emits neutrons.

In some embodiments, the dual mode detection device simultaneously emits electrons to an X-ray conversion target and a neutron conversion target through a single electron accelerator, X-rays generated by the X-ray conversion target emitted from the first detection port, and neutrons generated by the neutron conversion target emitted from the second detection port.

In some embodiments, determining the ratio of neutron to X-ray differential cross sections of the inspected object comprises:

determining a neutron mass attenuation condition of the inspected object according to the neutron object detection data and the neutron object-free detection data; determining an X-ray mass attenuation condition of the inspected object according to the X-ray object detection data and the X-ray object-free detection data; determining the ratio of neutron to X-ray differential cross sections of the inspected object according to the neutron mass attenuation condition and the X-ray mass attenuation condition of the inspected object.

In some embodiments, determining the ratio of neutron to X-ray differential cross sections of the inspected object comprises: determining the ratio F(n) of neutron n to the X-ray differential cross sections of the inspected object according to a formula:

F⁡(n)=σnσX=ln⁢⁢⁢In,0In,Dln⁢⁢IX,0IX,D

wherein σnis the neutron differential cross section of the inspected object, and σXis the X-ray differential cross section of the inspected object, In,0is the neutron object-free detection data, In,Dis the neutron object detection data, IX,0is the X-ray object-free detection data, and IX,Dis the X-ray object detection data.

In some embodiments, the dual mode detection method further comprises: determining relative contents of various nuclides in the inspected object according to the ratios of neutron to X-ray differential cross sections of the inspected object at different neutron energy.

In some embodiments, determining relative contents of various nuclides in the inspected object comprises: determining the relative contents A1˜Ak of various types of nuclides according to a formula:

[A1A2Ak]=[σn1,1σX,1,σn1,2σX,2,…⁢,σn1,kσX,kσn2,1σX,1,σn2,2σX,2,…⁢,σn2,kσX,kσnm,1σX,1,σnm,2σX,2,…⁢,σnm,kσX,m]-1⁡[F⁡(n1)F⁡(n2)F⁡(nm)]

where σni,jis the neutron differential cross section of the j-th nuclide in the i-th energy region, σX,jis the X-ray differential cross section of the j-th nuclide, F(ni) is the ratio of neutron to X-ray differential cross sections of the inspected object with respect to neutrons and X-rays in the i-th energy region, and Aj is the relative content of the j-th nuclide, 1≤i≤m,1≤j≤k, m is the number of neutron energy regions, k is the number of the nuclides types, wherein the number of energy regions is adjusted during the measurement so that m=k.

In some embodiments, the dual mode detection method further comprises imaging according to the ratio of neutron to X-ray differential cross sections of the inspected object.

According to another aspect of some embodiments of the present disclosure, a dual mode detection controller is provided, comprising: a ratio determination device configured to determine a ratio of neutron to X-ray differential cross sections of an inspected object, according to X-ray object detection data, X-ray object-free detection data, neutron object detection data, and neutron object-free detection data; a substance determination device configured to determine a substance type of the inspected object identification according to the ratio of neutron to X-ray differential cross sections of the inspected object.

In some embodiments, the ratio determination device comprises: a detection data acquisition unit configured to, when the inspected object is placed at a first detection port, obtain the X-ray object detection data according to a detection result of an X-ray detector, and obtain the neutron object-free detection data according to a detection result of a neutron detector; when the inspected object is placed at a second detection port, obtain the neutron object detection data according to a detection result of the neutron detector, and obtain the X-ray object-free detection data according to a detection result of the X-ray detector, wherein the first detection port emits X-rays, and the second detection port emits neutrons; a ratio calculation unit configured to determine the ratio of neutron to X-ray differential cross sections of the inspected object according to the X-ray object detection data, the X-ray object-free detection data, the neutron object detection data, and the neutron object-free detection data.

In some embodiments, the ratio calculation unit is configured to: determine a neutron mass attenuation condition of the inspected object according to the neutron object detection data and the neutron object-free detection data; determine an X-ray mass attenuation condition of the inspected object according to the X-ray object detection data and the X-ray object-free detection data; determine a ratio of neutron to X-ray differential cross sections of the inspected object according to the neutron mass attenuation condition and the X-ray mass attenuation condition of the object; determine a substance type of the inspected object according to a correspondence between the ratio of neutron to X-ray differential cross sections of the inspected object and the substance type.

In some embodiments, the ratio calculation unit is configured to: determine a ratio F(n) of neutron n to X-ray differential cross sections of the inspected object according to a formula:

F⁡(n)=σnσX=ln⁢⁢In,0In,Dln⁢⁢IX,0IX,D

wherein σnthe neutron differential cross section of the inspected object, and σXis the X-ray differential cross section of the inspected object, In,0is the neutron object-free detection data, In,Dis the neutron object detection data, IX,0is the X-ray object-free detection data, and IX,Dis the X-ray object detection data.

In some embodiments, the substance determination module is further configured to: determine relative contents of various nuclides in the inspected object according to ratios of neutron to X-ray differential cross sections of the inspected object at different neutron energy.

In some embodiments, determining relative contents of various nuclides in the inspected object comprises: determining the relative contents A1˜Akof various types of nuclides according to a formula:

[A1A2Ak]=[σn1,1σX,1,σn1,2σX,2,…⁢,σn1,kσX,kσn2,1σX,1,σn2,2σX,2,…⁢,σn2,kσX,kσnm,1σX,1,σnm,2σX,2,…⁢,σnm,kσX,m]-1⁡[F⁡(n1)F⁡(n2)F⁡(nm)]

where σni,jis the neutron differential cross section of the j-th nuclide in the i-th energy region, σX,jis the X-ray differential cross section of the j-th nuclide, F(ni) is the ratio of neutron to X-ray differential cross sections of the inspected object with respect to neutrons and X-rays in the i-th energy region, and Ajis the relative content of the j-th nuclide, 1≤i≤m,1≤j≤k, m is the number of neutron energy regions, k is the number of the nuclides types, wherein the number of energy regions is adjusted during the measurement so that m=k.

In some embodiments, the dual mode detection controller further comprises: an imaging device configured to perform imaging according to the ratio of neutron to X-ray differential cross sections of the inspected object.

According to another aspect of some embodiments of the present disclosure, a dual mode detection controller is provided, comprising: a memory; a processor coupled to the memory, the processor is configured to perform a method based on the program stored in the memory according to any dual mode detection method described above.

According to another aspect of some embodiments of the present disclosure, a computer-readable storage medium is provided on which computer program instructions are stored, which implement the steps of the method according to any dual mode detection method described above when executed by a processor.

According to an aspect of some embodiments of the present disclosure, a dual mode detection system is provided, comprising: any dual mode detection controller described above; and a dual mode detection device, comprising: a single electron accelerator configured to synchronously emit electrons to an X-ray conversion target and a neutron conversion target; the X-ray conversion target is configured to generate X-rays under excitation of electrons and emit the X-rays from a first detection port; the neutron conversion target is configured to generate neutrons under excitation of electrons and emit the neutrons from a second detection port.

In some embodiments, the dual mode detection device comprises at least one of: an X-ray chopper located between the neutron conversion target and the second detection port; an X-ray collimator located between the X-ray conversion target and the first detection port; or a neutron collimator located between the neutron conversion target and the second detection port.

In some embodiments, a line connecting the first detection port and the X-ray conversion target is substantially perpendicular to a line connecting the second detection port and the neutron conversion target.

