Patent Number: 
Section: claims

1. A radiation inspection system, comprising:a radiation source for emitting an initial beam and a beam modulating device for modulating the initial beam into a scanning beam, wherein the beam modulating device comprises a first collimating structure disposed at a beam exit side of the radiation source and a second collimating structure disposed at a beam exit side of the first collimating structure, the first collimating structure comprises a first collimating port, the second collimating structure comprises a second collimating port, the second collimating structure is movable relative to the first collimating structure to change a relative position of the first collimating port with the second collimating port, wherein the beam modulating device is shifted between a first operational state in which the beam modulating device modulates the initial beam into a fan beam, and a second operational state in which the beam modulating device modulates the initial beam into a pencil beam variable in position. 2. The radiation inspection system according to claim 1, wherein in the second operational state, the second collimating structure is translatable and/or rotatable relative to the first collimating structure to change an intersecting position of the second collimating port and the first collimating port in a direction perpendicular to an exit direction of the initial beam, thereby changing a position of the pencil beam. 3. The beam modulating device according to claim 1, wherein the first collimating structure comprises a first collimating plate; and the second collimating structure comprises a second collimating plate. 4. The radiation inspection system according to claim 3, wherein the first collimating plate is a first flat collimating plate, and the second collimating plate is a second collimating flat plate; or, the first collimating plate is a first collimating curved plate, and the second collimating plate is a second collimating curved plate. 5. The radiation inspection system according to claim 3, wherein the first collimating plate is parallel to the second collimating plate. 6. The radiation inspection system according to claim 1, wherein the first collimating port is a first collimating slit; and the second collimating port is a second collimating slit. 7. The radiation inspection system according to claim 1, wherein at least one of the first collimating slit and the second collimating slit is a straight-linear collimating slit. 8. The radiation inspection system according to claim 7, wherein the second collimating slit is disposed obliquely or vertically with respect to the first collimating slit. 9. The radiation inspection system according to claim 1, wherein:the first collimating structure is stationary, and the second collimating structure is movably disposed; or,the first collimating structure is movably disposed, and the second collimating structure is stationary; orthe first collimating structure and the second collimating structure are movably disposed. 10. The radiation inspection system according to claim 1, wherein the radiation source comprises a neutron source. 11. The radiation inspection system according to claim 10, wherein the neutron source comprises a photoneutron source. 12. The radiation inspection system according to claim 10, wherein the radiation inspection system further comprises a neutron modulating mask, which is disposed on the periphery of the neutron source, to modulate neutrons generated by the neutron source. 13. The radiation inspection system according to claim 12, wherein the neutron modulating mask comprises a moderating layer, which is disposed at the periphery of the neutron source to moderate the neutrons produced by the neutron source. 14. The radiation inspection system according to claim 13, wherein the neutron modulating mask comprises a shielding layer, shielding layer is disposed at the periphery of the moderating layer and comprises a shielding portion that shields the moderated neutrons and a neutron exit port that is disposed on the beam exit side for emitting the initial beam. 15. The radiation inspection system according to claim 1, comprising a detection device and a controller, wherein the detection device is configured to receive photons scattered by an inspected object radiated by the scanning beam, and the controller is coupled to the detection device to receive a detection signal from the detection device and form an inspection result according to the detection signal. 16. The radiation inspection system according to claim 15, wherein the detection device comprises a first detecting module and a second detecting module having an energy resolution higher than the first detecting module, wherein the first detecting module and the second detecting module are configured to receive the photons scattered by the inspected object radiated by the scanning beam; the controller is coupled to the first detecting module to receive a first detection signal from the first detecting module and form a first inspection result according to the first detection signal; the controller is also coupled to the second detecting module to receive a second detection signal from the second detecting module and to form a second inspection result according to the second detection signal. 17. The radiation inspection system according to claim 16, wherein the detection device comprises a first detecting module foreground collimating structure for forming a beam shape of the photons entering the first detecting module; and/or the detection device comprises a second detecting module foreground collimating structure for forming a beam shape of the photons entering the second detecting module. 18. The radiation inspection system according to claim 16, wherein in the second operational state, the second detecting module is fixed in position with respect to the pencil beam in a detecting process. 19. A radiation inspection method, for inspecting an inspected subject by using the radiation inspection system according to claim 1, comprising:placing the beam modulating device in a first operational state, and scanning the inspected subject by using the fan beam to determine a suspected area to be accurately inspected; andplacing the beam modulating device in a second operational state, and accurately scanning the suspected area by using the pencil beam. 20. The radiation inspection method according to claim 19, wherein the radiation inspection system comprises a first detecting module and a second detection having an energy resolution higher than the first detecting module, and the radiation inspection method comprises:in the first operational state, the first detecting module detects separately, or the first detecting module and the second detecting module detect simultaneously to determine the suspected area;in the second operational state, the second detecting module detects separately, or the first detecting module and the second detecting module detect simultaneously to accurately inspect the suspected area.