Radiation inspection system

Abstract

The invention provides a radiation inspection system which is provided with an inspection channel for an inspected object to pass through and comprises a transmission inspection device, a back scattering inspection device, a signal processing device and an image processing device. The transmission inspection device comprises a transmission ray source and a transmission detector which are arranged on the two opposite sides of the inspection channel. The back scattering inspection device comprises a back scattering ray source and a back scattering detector which are arranged on the same side of the inspection channel. The transmission ray beam output time of the transmission ray source and the pencil-shaped ray beam output time of the back scattering ray source are staggered. And the back scattering signal correction device is in signal connection with the back scattering detector and is configured to deduct an afterglow signal generated by the transmission ray beam to the back scattering detector from a back scattering detection signal generated by the back scattering detector when the pencil-shaped ray beam is output so as to form a back scattering correction signal. And the back scattering image processing device is in signal connection with the back scattering signal correction device and is configured to form a back scattering image according to the back scattering correction signal.

Description

Technical Field

[0001] The present application relates to the technical field of radiation inspection, and in particular to a radiation inspection system. Background Art

[0002] Radiation inspection systems used for inspected objects such as containers and vehicles can be divided into transmission inspection systems and backscatter inspection systems from the perspective of imaging principles.

[0003] The transmission inspection system includes a transmission inspection device and a transmission image processing device. The transmission inspection device includes a transmission ray source and a transmission detector which are arranged on opposite sides of the inspection channel. In the transmission inspection system, the transmission ray beam output by the transmission ray source passes through the inspected object located in the inspection channel and is attenuated and then detected by the transmission detector located on the other side of the inspected object to obtain a transmission detection signal. The transmission image processing device processes the transmission detection signal to obtain a transmission image. The transmission detection signal detected by the transmission detector reflects information such as the density and thickness of the inspected object and can display the internal structure of the inspected object. The transmission inspection system has the advantages of strong penetration and good image quality.

[0004] The backscatter inspection system includes a backscatter inspection device and a backscatter image processing device. The backscatter inspection device includes a backscatter ray source and a backscatter detector located on the same side of the inspection channel. The backscatter inspection system uses the Compton scattering effect to emit a pencil beam of rays to the inspected object located in the inspection channel through the backscatter ray source. The backscatter detector located on the same side of the backscatter ray source captures the backscatter rays reflected by the inspected object to obtain a backscatter detection signal. The backscatter image processing device processes the backscatter detection signal to obtain a backscatter image. Since the Compton scattering of rays in low atomic number materials such as explosives and drugs is stronger, the backscatter system can distinguish materials and highlight organic substances.

[0005] Whether it is a transmission inspection system or a backscatter inspection system, from the perspective of imaging, the radiation inspection system can be divided into a single-view inspection system and a multi-view inspection system. A multi-view radiation inspection system can, for example, use a combination of different view angles such as a side view angle, a top view angle, and a bottom view angle. A multi-view radiation inspection system can inspect the object being inspected more comprehensively from different angles.

[0006] The transmission inspection system and the backscatter inspection system each have their own advantages. A radiation inspection system that integrates both radiation inspection technologies can provide two scanning images, a transmission image and a backscatter image, after the radiation inspection is completed, thus combining the advantages of both. In a radiation inspection system that integrates both radiation inspection technologies, radiation inspection using multiple viewing angles has the advantages of transmission inspection, backscatter inspection, and multi-viewing angle inspection.

[0007] Generally, the detectors of radiation inspection systems have an afterglow effect. The afterglow effect refers to the phenomenon that when a detector is used for detection, after being exposed to light or radiation, it will continue to emit weak light or signals for a period of time even without light or radiation. The afterglow effect may cause unexpected continuous light or signals in the image, which will affect the image quality.

[0008] In a radiation inspection system that integrates two radiation inspection technologies, the transmission ray beam output by the transmission ray source of the transmission inspection device is a high-energy ray with high energy and high dose. If the backscatter detector is in a position where it can receive the transmission ray beam (whether before or after attenuation), it will still generate an afterglow signal under the influence of the transmission ray beam and the afterglow effect for a period of time after the transmission ray beam stops outputting. For example, if the transmission ray source is an accelerator that emits a beam in a pulsed manner, even if the pulse width of the transmission ray beam emitted by the accelerator is only 3~5μs, if the backscatter inspection device and the transmission inspection device are relatively close along the extension direction of the inspection channel, so that the backscatter detector is in a position where it can receive the transmission ray beam, after a certain pulse output of the accelerator is completed, the backscatter detector will still be affected by the pulse and generate an afterglow signal.

[0009] In the related art, in a radiation inspection system integrating two radiation inspection technologies, in order to prevent the transmission ray beam generated by the transmission ray source of the transmission inspection device from affecting the backscatter detection signal of the backscatter detector of the backscatter inspection device, a certain distance is usually set between the transmission inspection device and the backscatter inspection device along the extension direction of the inspection channel, and the distance is usually more than 5 meters. Such arrangement of the transmission inspection device and the backscatter inspection device will cause the radiation inspection system to occupy too large an area.

[0010] The above statements are only used to provide background information related to the present application and do not necessarily constitute prior art. Summary of the invention

[0011] The purpose of the present application is to provide a radiation inspection system, aiming to solve the problem that the radiation inspection system integrating two radiation inspection technologies occupies too large an area.

[0012] The present application provides a radiation inspection system having an inspection channel for an inspected object to pass through, including:

[0013] a transmission inspection device, comprising a transmission ray source and a transmission detector disposed on opposite sides of the inspection channel, and configured to perform a transmission inspection on the inspected object passing through the inspection channel; and

[0014] A backscatter inspection device, comprising a backscatter ray source and a backscatter detector arranged on the same side of the inspection channel, configured to perform backscatter inspection on the inspected object passing through the inspection channel, wherein the time when the transmission ray source outputs the transmission ray beam is staggered with the time when the backscatter ray source outputs the pencil ray beam;

[0015] a backscatter signal correction device, connected to the backscatter detector signal, configured to subtract an afterglow signal generated by the transmitted ray beam output by the transmitted ray source on the backscatter detector from the backscatter detection signal generated by the backscatter detector when the pencil ray beam is output, so as to form a backscatter correction signal; and

[0016] The backscatter image processing device is signal-connected to the backscatter signal correction device and is configured to form a backscatter image according to the backscatter correction signal.

[0017] In the radiation inspection system described in some embodiments,

[0018] The afterglow signal is formed according to pre-stored data pre-stored in the backscatter signal correction device; or

[0019] The afterglow signal is acquired on-site according to the backscatter detection signal of the backscatter detector when the output of the transmitted ray beam stops and the pencil ray beam is not output when the radiation inspection system is working.

[0020] In the radiation inspection system described in some embodiments, the backscatter signal correction device acquires the afterglow signal on-site multiple times and forms a backscatter correction signal according to the afterglow signal acquired on-site most recently.

[0021] In the radiation inspection system described in some embodiments,

[0022] Each time the transmitted ray source outputs the transmitted ray beam, the backscatter signal correction device acquires the afterglow signal on site once; or

[0023] The flying spot device of the backscattered ray source comprises a fixed part and a movable part which moves periodically relative to the fixed part. The backscattered signal correction device acquires the afterglow signal once on site each time the movable part moves one cycle.

[0024] In the radiation inspection system described in some embodiments,

[0025] The transmission ray source outputs the transmission ray beam in a pulsed manner;

[0026] The backscattered ray source outputs the pencil ray beam in an interval time period between adjacent transmitted ray beams;

[0027] The backscatter signal correction device obtains the afterglow signal on-site according to the backscatter detection signal in the silent time period when the backscatter detector stops outputting the pencil ray beam except in the interval time period of the adjacent transmission ray beams.

[0028] In the radiation inspection system described in some embodiments, the backscattered ray source includes a radiation source and a flying spot device, the flying spot device includes a fixed part fixed relative to the radiation source and a movable part periodically moving relative to the fixed part, and the flying spot device is configured to output or stop outputting the pencil ray beam through relative movement of the fixed part and the movable part.

[0029] In the radiation inspection system described in some embodiments, the backscatter signal correction device fits an afterglow attenuation curve according to the backscatter detection signal of the backscatter detector during the silent time period, and forms the afterglow signal according to the afterglow attenuation curve.

[0030] In the radiation inspection system described in some embodiments, the afterglow attenuation curve is ,in,

[0031] t is the fitting time;

[0032] I t is the afterglow signal at fitting time t;

[0033] I 0 is the backscatter detection signal when the fitting time t is zero;

[0034] τ is the decay time constant of the backscatter detector.

[0035] In the radiation inspection system described in some embodiments, the transmission inspection device and the backscatter inspection device are configured so that the transmission ray beam and the pencil ray beam are coplanar.

[0036] In the radiation inspection system described in some embodiments, the radiation inspection system includes two or more backscatter inspection devices with different viewing angles and / or two or more transmission inspection devices with different viewing angles.

[0037] In the radiation inspection system described in some embodiments, a pencil ray beam is output once or multiple times within an interval time period of each adjacent transmission ray beam.

[0038] In the radiation inspection system described in some embodiments, multiple pencil beams are output within an interval time period of each adjacent transmitted beam, wherein the output order of the multiple pencil beams is arranged from the smallest to the largest influence of the afterglow signal of the transmitted beam on the backscatter detector receiving the pencil beam.

[0039] In the radiation inspection system described in some embodiments, the backscatter detector includes a plastic scintillator or a GAGG crystal.

[0040] Based on the radiation inspection system provided by the present application, since a backscatter signal correction device connected to the backscatter detector signal is provided, the backscatter signal correction device can deduct the afterglow signal generated by the transmitted ray beam output by the transmitted ray source on the backscatter detector from the backscatter detection signal generated by the backscatter detector to form a backscatter correction signal. A backscatter image processing device is signal-connected to the backscatter signal correction device to form a backscatter image according to the backscatter correction signal. Therefore, even if the backscatter detector is in a position where it can receive the transmitted ray beam, since the backscatter image is obtained based on the backscatter correction signal formed by deducting the afterglow signal from the backscatter detection signal, a relatively realistic backscatter image of the inspected object can still be obtained. Therefore, the transmission inspection device and the backscatter inspection device can be arranged at a closer distance along the extension direction of the inspection channel than in the related art, thereby reducing the total length of the radiation inspection system along the extension direction of the inspection channel, which is beneficial to solving the problem of excessive floor space occupied by the radiation inspection system integrating two radiation inspection technologies.

[0041] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0043] Figure 1 It is a principle block diagram of a radiation inspection system according to an embodiment of the present application, wherein the radiation inspection system includes a transmission inspection device and a backscatter inspection device.

[0044] Figure 2 for Figure 1 A schematic structural diagram of a backscatter ray source of a backscatter inspection device of a radiation inspection system of the illustrated embodiment.

[0045] Figure 3 for Figure 1 The schematic diagram of the timing of the transmission ray source of the transmission inspection device of the radiation inspection system of the illustrated embodiment emitting a transmission ray beam and the pencil ray beam output by the backscattering ray source of the backscattering inspection device.

[0046] Figure 4 for Figure 1A schematic diagram of an afterglow attenuation curve fitted by a backscatter signal correction device of a radiation inspection system of the illustrated embodiment.

[0047] Figure 5 for Figure 1 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0048] Figure 6 This is a schematic diagram of the arrangement of a transmission inspection device and a backscatter inspection device relative to an inspection channel of a radiation inspection system of an embodiment of the present application, wherein the radiation inspection system includes one transmission inspection device and four backscatter inspection devices.

[0049] Figure 7 for Figure 6 The schematic diagram of the timing of the transmission ray source of the transmission inspection device of the radiation inspection system of the illustrated embodiment emitting a transmission ray beam and the pencil ray beam output by the backscattering ray source of the backscattering inspection device.

[0050] Figure 8 for Figure 6 and Figure 7 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0051] Fig. 9 for Figure 6 and Figure 7 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in another alternative embodiment of the radiation inspection system of the illustrated embodiment.

[0052] Fig.10 for Figure 6 and Figure 7 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in yet another alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0053] Fig.11 This is a schematic diagram of the arrangement of a transmission inspection device and a backscatter inspection device relative to an inspection channel of a radiation inspection system according to an embodiment of the present application, wherein the radiation inspection system includes a transmission inspection device and three backscatter inspection devices.

[0054] Fig.12 for Fig.11The schematic diagram of the timing of the transmission ray source of the transmission inspection device of the radiation inspection system of the illustrated embodiment emitting a transmission ray beam and the pencil ray beam output by the backscattering ray source of the backscattering inspection device.

[0055] Fig.13 for Fig.11 and Fig.12 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0056] Fig.14 for Fig.11 and Fig.12 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in another alternative embodiment of the radiation inspection system of the illustrated embodiment.

[0057] Fig.15 This is a schematic diagram of the arrangement of a transmission inspection device and a backscatter inspection device relative to an inspection channel of a radiation inspection system of an embodiment of the present application, wherein the radiation inspection system includes a transmission inspection device and two backscatter inspection devices.

[0058] Fig.16 for Fig.15 The schematic diagram of the timing of the transmission ray source of the transmission inspection device of the radiation inspection system of the illustrated embodiment emitting a transmission ray beam and the pencil ray beam output by the backscattering ray source of the backscattering inspection device.

[0059] Fig.17 for Fig.15 and Fig.16 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0060] Fig.18 for Fig.15 and Fig.16 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source of a transmission inspection device and a pencil ray beam output by a backscatter ray source of a backscatter inspection device in another alternative embodiment of the radiation inspection system of the illustrated embodiment. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0062] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0063] In the description of the present application, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present application.

[0064] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0065] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0066] The present application provides a radiation inspection system having an inspection channel P for an inspected object to pass through, including a transmission inspection device 10, a backscatter inspection device 20, a signal processing device, and an image processing device.

[0067] The transmission inspection device 10 includes a transmission ray source 11 and a transmission detector 12 disposed on opposite sides of an inspection channel P, and is configured to perform transmission inspection on an object to be inspected passing through the inspection channel P.

[0068] The backscatter inspection device 20 includes a backscatter ray source 21 and a backscatter detector 22 disposed on the same side of the inspection channel P, and is configured to perform backscatter inspection on the inspected object passing through the inspection channel P. The time when the transmission ray source 11 outputs the transmission ray beam is staggered with the time when the backscatter ray source 21 outputs the pencil ray beam.

[0069] The backscatter signal correction device 30 is connected to the backscatter detector 22 signal, and is configured to subtract the afterglow signal generated by the transmitted ray beam output by the transmitted ray source 11 on the backscatter detector 22 from the backscatter detection signal generated by the backscatter detector 22 when the pencil ray beam is output to form a backscatter correction signal.

[0070] The backscatter image processing device 50 is signal-connected to the backscatter signal correction device 30 and is configured to form a backscatter image based on the backscatter correction signal.

[0071] In the radiation inspection system integrating the two radiation inspection technologies of transmission and backscattering in the related art, if the backscattering detector 22 is in a position where it can receive the transmission beam, when the backscattering inspection device 20 starts scanning, that is, when the pencil beam output by the backscattering ray source scans the inspected object, the backscattering detector of the backscattering inspection device 20 starts to collect the backscattered rays of the inspected object. Due to the influence of afterglow, the backscattering detection signal output by the backscattering detector 22 still includes the afterglow signal generated on the backscattering detector by the transmission beam output by the transmission ray source 11. When the backscattering inspection device 20 performs the inspection, the backscattering detection signal of the backscattering detector 22 includes both the real backscattering signal and the afterglow signal generated by the afterglow of the transmission beam, so the backscattering detection signal of the backscattering detector 22 cannot truly reflect the backscattering signal of the inspected object. That is to say, even when the transmission ray source 11 does not emit a beam, the backscattering detection signal output by the backscattering detector 22 still includes the afterglow signal affected by the transmission beam generated by the transmission ray source 11. If the backscatter detector 22 uses a crystal with a relatively long afterglow decay time (such as BaFCl), the backscatter detection signal output by the backscatter detector 22 will be more seriously affected by the afterglow brought by the transmitted ray beam.

[0072] In the radiation inspection system of the embodiment of the present application, since a backscatter signal correction device 30 connected to the backscatter detector 22 by signal is provided, the backscatter signal correction device 30 can deduct the afterglow signal generated by the transmitted ray beam output by the transmitted ray source 11 on the backscatter detector 22 from the backscatter detection signal generated by the backscatter detector 22 to form a backscatter correction signal. The backscatter image processing device 50 is connected to the backscatter signal correction device 30 by signal and forms a backscatter image according to the backscatter correction signal. Therefore, even if the backscatter detector 22 is in a position where it can receive the transmitted ray beam, since the backscatter image is obtained based on the backscatter correction signal formed by deducting the afterglow signal from the backscatter detection signal, a relatively true backscatter image of the inspected object can still be obtained. Therefore, the transmission inspection device 10 and the backscatter inspection device 20 can be arranged at a distance closer to each other along the extension direction of the inspection channel P than in the related art, thereby reducing the total length of the radiation inspection system along the extension direction of the inspection channel P, which is beneficial to solving the problem of excessive floor space occupied by the radiation inspection system integrating two radiation inspection technologies.

[0073] In the radiation inspection system of some embodiments, the afterglow signal is formed based on pre-stored data in the backscatter signal correction device 30; or the afterglow signal is acquired on-site based on the backscatter detection signal of the backscatter detector when the transmission beam output stops and the pencil beam is not output when the radiation inspection system is working.

[0074] The afterglow signal is formed according to the pre-stored data pre-stored in the backscatter signal correction device 30. The afterglow signal generated by the transmission ray source 11 to the backscatter detector 22 can be tested in advance and stored in the storage unit of the backscatter signal correction device 30. When the backscatter imaging signal is formed, the backscatter signal correction device 30 directly retrieves the afterglow signal stored in the storage unit, and deducts the afterglow signal generated by the transmission ray beam output by the transmission ray source 11 to the backscatter detector 22 from the backscatter detection signal generated by the backscatter detector 22 when the pencil ray beam is output to form a backscatter correction signal. For example, when testing in advance, the afterglow signal test can be started after the transmission ray source 11 stops emitting the transmission ray beam, and the test is terminated after the test lasts for a period of time that can cover the time period when the backscatter ray source 21 emits the pencil ray beam. After a series of test data is obtained, the afterglow signal of the entire test period can be obtained by forming a fitting curve or using an interpolation method to form supplementary data. By obtaining the afterglow signal in this way, a more accurate backscatter correction signal can be obtained, so that the backscatter image obtained according to the backscatter correction signal is more realistic. If the parameters of the transmitted ray beam emitted by the transmitted ray source 11 are adjustable, multiple groups of afterglow signals corresponding to the parameters of the transmitted ray beam can be tested. When the backscatter signal correction device 30 retrieves the afterglow signal in the storage device, it needs to call the afterglow signal corresponding to the parameters of the transmitted ray beam.

[0075] The afterglow signal is acquired on-site based on the backscatter detection signal of the backscatter detector when the output of the transmitted ray beam stops and the pencil ray beam is not output when the radiation inspection system is working. This is beneficial for forming the afterglow signal based on the influence of the transmitted ray beam detected instantly by the backscatter detector. The afterglow signal acquired on-site can be made to follow the parameters of the transmitted ray beam when the radiation inspection system is working, thereby obtaining a more accurate backscatter correction signal, and making the backscatter image obtained based on the backscatter correction signal more realistic.

[0076] For example, in order to obtain the afterglow signal on site, the backscatter ray source can be selected to stop outputting the pencil ray beam during an interval time period when the transmission ray source 11 emits the transmission ray beam twice. The backscatter detection signal detected by the backscatter detector during the interval time period is the afterglow signal formed by the backscatter detector being affected by the transmission ray beam emitted before the interval time period. After the afterglow signal is obtained, the backscatter correction signal when the backscatter ray source normally outputs the pencil ray beam can be used on site. In this way, the afterglow signal obtained on site is complete and accurate, the backscatter correction signal obtained is more accurate, and the backscatter image formed is more realistic.

[0077] In the radiation inspection system of some embodiments, the backscatter signal correction device 30 acquires the afterglow signal on-site for multiple times and forms a backscatter correction signal according to the afterglow signal acquired on-site the most recently.

[0078] The backscatter signal correction device acquires the afterglow signal on site more than 30 times and forms a backscatter correction signal according to the afterglow signal acquired on site the most recently, which is conducive to forming a backscatter correction signal at any time according to the afterglow signal formed by the parameters of the transmitted ray beam, thereby obtaining a more realistic backscatter image.

[0079] In the radiation inspection system of some embodiments, the backscatter signal correction device 30 obtains an afterglow signal on-site once each time the transmitted ray source 11 outputs a transmitted ray beam; or the flying spot device 212 of the backscatter ray source 21 includes a fixed part 2121 and a movable part 2122 that periodically moves relative to the fixed part 2121, and the backscatter signal correction device 30 obtains an afterglow signal on-site once each time the movable part 2122 moves one cycle.

[0080] The above-mentioned frequency settings of the on-site acquisition of the afterglow signal are all conducive to the afterglow signal to follow the parameters of the transmission ray speed in time, thereby facilitating the formation of a more realistic backscatter correction signal according to the parameters of the transmission ray beam at any time, and thus obtaining a more realistic backscatter image.

[0081] In the radiation inspection system of some embodiments, the transmitted ray source 11 outputs a transmitted ray beam in a pulsed manner; the backscattered ray source 21 outputs a pencil ray beam in the interval time period between adjacent transmitted ray beams; the backscattered signal correction device 30 obtains an afterglow signal on-site based on the backscattered detection signal during the silent time period when the backscattered detector 22 stops outputting the pencil ray beam except for the time period when the backscattered detector 22 outputs the pencil ray beam in the interval time period between adjacent transmitted ray beams.

[0082] In the radiation inspection system of this embodiment, the backscatter ray source may not emit a pencil ray beam during a silent period in an interval time period between two transmission ray beams emitted by the transmission ray source 11, and the remaining time period is a beam-out period in which the backscatter ray source normally outputs a pencil ray beam. The backscatter detection signal detected by the backscatter detector 22 during the silent period in the interval time period is an afterglow signal formed by the backscatter detector 22 being affected by the transmission ray beam emitted before the interval time period, and the afterglow signal in the beam-out period in the interval time period is obtained by the afterglow signal in the silent period. After the afterglow signal in the beam-out period in the interval time period is obtained, the afterglow signal in the beam-out period can be used when obtaining the backscatter correction signal when the backscatter ray source 21 normally outputs a pencil ray beam on site. The afterglow signal obtained during the inspection in this way does not need to stop the backscatter ray source from outputting a pencil ray beam in order to obtain the afterglow signal. On the basis that the obtained backscatter correction signal is relatively accurate and the formed backscatter image is relatively real, there is no need to interrupt the radiation inspection, so that the efficiency of the radiation inspection is high.

[0083] In the radiation inspection system of some embodiments, the backscattered ray source 21 includes a radiation source 211 and a flying spot device 212, the flying spot device 212 includes a fixed part 2121 fixed relative to the radiation source 211 and a movable part 2122 periodically moving relative to the fixed part 2121, and the flying spot device 212 is configured to output or stop outputting a pencil ray beam through the relative movement of the fixed part 2121 and the movable part 2122.

[0084] The flying spot device 212 is configured to output or stop outputting a pencil ray beam through the relative movement of the fixed portion 2121 and the movable portion 2122. The structural arrangement of the fixed portion 2121 and the movable portion 2122 of the flying spot device 212 can achieve corresponding control of the silent time period and the beam-emitting time period of the backscattered ray source without acquiring an afterglow signal on site, thereby not increasing the complexity of controlling the backscattered ray source due to acquiring an afterglow signal on site.

[0085] In the radiation inspection system of some embodiments, the backscatter signal correction device 30 fits an afterglow attenuation curve according to the backscatter detection signal of the backscatter detector 22 during the silent period, and forms an afterglow signal according to the afterglow attenuation curve.

[0086] The afterglow attenuation curve is fitted according to the backscatter detection signal of the backscatter detector 22 in the silent period, and the afterglow signal in the beam-out period can be formed according to the afterglow attenuation curve, so as to obtain a more accurate backscatter correction signal and a more realistic backscatter image.

[0087] In the radiation inspection system of some embodiments, the afterglow attenuation curve is: ,in,

[0088] t is the fitting time;

[0089] I t is the afterglow signal at fitting time t;

[0090] I 0 is the backscatter detection signal when the fitting time t is zero;

[0091] τ is the decay time constant of the backscatter detector 22 .

[0092] The persistence decay curve is set to The fitted curve is in the form of a more suitable detector type, and the fitting effect is better, so the obtained afterglow signal is more accurate, which is conducive to obtaining a more accurate backscatter correction signal and a more realistic backscatter image.

[0093] In the radiation inspection system of some embodiments, the transmission inspection device 10 and the backscatter inspection device 20 are configured so that the transmission ray beam and the pencil ray beam are coplanar.

[0094] The transmission inspection device 10 and the backscatter inspection device 20 are configured so that the transmission ray beam and the pencil ray beam are coplanar, which can minimize the space occupied by the transmission inspection device 10 and the backscatter inspection device 20 along the extension direction of the inspection channel P, thereby maximizing the reduction of the total length of the radiation inspection system along the extension direction of the inspection channel P, and more effectively solving the problem of excessive floor space occupied by the radiation inspection system integrating two radiation inspection technologies. As generally understood in the art, coplanarity in this application means that the scanning surface of the transmission ray beam is coplanar or approximately coplanar with the scanning surface of the pencil ray beam. In some embodiments of the radiation inspection system, the radiation inspection system includes more than two backscatter inspection devices 20 with different viewing angles and / or more than two transmission inspection devices 10 with different viewing angles. In addition, if the transmission inspection device 10 and the backscatter inspection device 20 are separated by a certain distance, the transmission image and the backscatter image need to be aligned so that each position of the two images corresponds to each other, so as to facilitate the comparison and viewing of the two images at the same position of the inspected object. However, if the transmission inspection device 10 and the backscatter inspection device 20 are configured so that the transmission ray beam and the pencil ray beam are coplanar, there is no need for alignment operation, and the two images at the same position can be directly compared and viewed.

[0095] The radiation inspection system includes more than two backscatter inspection devices 20 with different viewing angles and / or more than two transmission inspection devices 10 with different viewing angles, which is beneficial to further concentrate the advantages of multi-view radiation inspection in the radiation inspection system that integrates two radiation inspection technologies. Moreover, since the influence of the afterglow signal is deducted from the backscatter detection signal, even if the radiation inspection system includes more than two backscatter inspection devices 20 with different viewing angles and / or more than two transmission inspection devices 10 with different viewing angles, the floor space occupied will not be increased due to multi-view inspection. Therefore, the problem of excessive floor space occupied by the radiation inspection system that integrates two radiation inspection technologies can still be solved on the basis of adopting the multi-view radiation inspection technology.

[0096] In the radiation inspection system of some embodiments, the pencil ray beam is output once or multiple times within an interval time period of each adjacent transmission ray beam.

[0097] By outputting a pencil ray beam once or multiple times within the interval time period of each adjacent transmitted ray beam, the inspection time of the transmission inspection device and the backscatter inspection device can be reasonably allocated according to the output frequency of the transmitted ray beam and the output frequency of the pencil ray beam, which is beneficial to improving the inspection efficiency of the radiation inspection system.

[0098] In the radiation inspection system of some embodiments, multiple pencil beams are output within the interval time period of each adjacent transmitted beam, wherein the output order of the multiple pencil beams is arranged from the smallest to the largest order in which the backscatter detector 22 receiving the pencil beam is affected by the afterglow signal of the transmitted beam.

[0099] The output order of multiple pencil beams is arranged from the smallest to the largest influence of the afterglow signal of the transmitted beam on the backscatter detector 22 receiving the pencil beam, which helps to minimize the influence of the afterglow signal on the backscatter detection signal of each backscatter detector 22, thereby facilitating the acquisition of a more accurate backscatter correction signal and a more realistic backscatter image.

[0100] In the radiation inspection system of some embodiments, the backscatter detector 22 includes a plastic scintillator or a GAGG crystal.

[0101] Plastic scintillators or GAGG (gadolinium gallium aluminum garnet) crystals have a shorter afterglow decay time than other types of backscatter detectors 22, which helps to further reduce the deviation between the backscatter correction signal and the real backscatter signal of the pencil ray beam completely reflected by the inspected object, thereby making the backscatter image more realistic.

[0102] The following combination Figures 1 to 18 The radiation inspection system of the embodiment of the present application is described in detail.

[0103] Figure 1 The schematic block diagram of the radiation inspection system of one embodiment of the present application is as follows. The radiation inspection system is a single-view radiation inspection system that integrates two radiation inspection technologies, namely, transmission inspection device and backscatter inspection device, and is suitable for radiation scanning inspection of inspected objects such as containers or vehicles.

[0104] like Figure 1 As shown, the radiation inspection system of this embodiment has an inspection channel P for the inspected object to pass through, including a transmission inspection device 10, a backscatter inspection device 20, a backscatter signal correction device 30, a transmission image processing device 40, a backscatter image processing device 50, a display device 60 and a control device 70.

[0105] The transmission inspection device 10 includes a transmission ray source 11 and a transmission detector 12 disposed on opposite sides of an inspection channel P, and is configured to perform a transmission inspection on an object to be inspected passing through the inspection channel P. The transmission inspection device 10 may, for example, use an accelerator or an isotope source as the transmission ray source 11, and the high-energy X-rays emitted by the accelerator or the Gamma rays emitted by the isotope source as a transmission ray beam pass through the object to be inspected passing through the inspection channel P, and then attenuate and are detected by the transmission detector 12 located on the other side of the object to be inspected to form a transmission detection signal.

[0106] The backscatter inspection device 20 includes a backscatter ray source 21 and a backscatter detector 22 disposed on the same side of the inspection channel P, and is configured to perform backscatter inspection on the inspection object passing through the inspection channel P. The backscatter detector 22 includes a plastic scintillator or a GAGG crystal.

[0107] The transmission inspection device 10 and the backscatter inspection device 20 are configured so that the transmission ray beam and the pencil ray beam are coplanar. The beam-out scanning directions of the transmission ray beam and the pencil ray beam are both toward the scanning channel P and perpendicular to the extension direction of the scanning channel P.

[0108] Figure 2 for Figure 1 A schematic structural diagram of a backscatter ray source 21 of a backscatter inspection device 20 of a radiation inspection system of the illustrated embodiment.

[0109] like Figure 2 As shown, the backscattered ray source 21 includes a radiation source 211 and a flying spot device 212, and the flying spot device 212 includes a fixed portion 2121 fixedly arranged relative to the radiation source 211 and a movable portion 2122 that periodically moves relative to the fixed portion 2121. The flying spot device 212 is configured to output or stop outputting a pencil ray beam through the relative movement of the fixed portion 2121 and the movable portion 2122. The radiation source 211 is, for example, an X-ray source.

[0110] like Figure 2As shown, in the embodiment of the present application, the fixed part 2121 is a fan-shaped box, and the beam outlet position of the radiation source 211 is set at the radial center of the fan-shaped box. The movable part 2122 includes a rotating ring, and the rotating ring is provided with a beam hole 21221. The movable part 2122 is sleeved outside the fan-shaped box, and the radial outer side of the fan-shaped box has an arc-shaped notch consistent with the diameter of the rotating ring. The movable part 2122 is rotatably arranged around the center of the rotating ring.

[0111] like Figure 2 As shown, in the embodiment of the present application, the fan-shaped box and the rotating ring are eccentrically arranged, and the fan-shaped box is 90° with the beam exit point G of the radiation source 211 as the center. In an embodiment not shown in the figure, the fan-shaped box and the rotating ring can be arranged concentrically.

[0112] Figure 2 In the embodiment, the rotating ring has three beam holes 21221 spaced at an angle of 120°. Therefore, each time the rotating ring rotates one circle, the three beam holes 21221 sequentially pass through the arc-shaped notch of the fan-shaped box once, and the pencil-shaped ray beam is output three times, that is, the backscattered ray source completes three scans.

[0113] When the backscatter inspection device 20 performs radiation scanning inspection, the X-ray source X-ray beam is collimated into a pencil beam through the fan-shaped box and the beam hole 21221. During the high-speed rotation of the rotating ring, only one beam hole 21221 can emit a pencil beam at the same time. The pencil beam is a thin beam of X-rays and performs a one-dimensional high-speed line scan in the vertical direction. At the same time, the object to be inspected moves in the inspection channel P along the extension direction of the inspection channel P, and generates relative motion with the radiation inspection system. The backscatter detector detects the backscatter rays reflected from the object to be inspected, so that a two-dimensional backscatter image of the object to be inspected can be obtained according to the backscatter detection signal detected by the backscatter detector.

[0114] like Figure 3 As shown, the time when the transmission ray source 11 outputs the transmission ray beam is staggered with the time when the backscattered ray source 21 outputs the pencil ray beam.

[0115] like Figure 1 As shown, the backscatter signal correction device 30 is signal-connected to the backscatter detector 22. The backscatter signal correction device 30 is configured to deduct the afterglow signal generated by the transmitted ray beam output by the transmitted ray source 11 to the backscatter detector 22 from the backscatter detection signal generated by the backscatter detector 22 to form a backscatter correction signal.

[0116] In this embodiment, the afterglow signal is acquired on-site based on the backscatter detection signal of the backscatter detector when the transmission beam output stops and the pencil beam is not output when the radiation inspection system is working. The backscatter signal correction device 30 acquires the afterglow signal on-site multiple times and forms a backscatter correction signal based on the afterglow signal acquired on-site the most recently. Every time the transmission ray source 11 outputs a transmission beam, the backscatter ray source 21 outputs a pencil beam, and the backscatter signal correction device 30 acquires the afterglow signal on-site once.

[0117] The transmission ray source 11 is an accelerator that outputs a transmission ray beam in a pulsed manner. The backscatter ray source 21 outputs a pencil ray beam in the interval time period between adjacent transmission ray beams. The backscatter signal correction device 30 obtains an afterglow signal on-site based on the backscatter detection signal of the backscatter detector 22 in the silent time period when the pencil ray beam is stopped except when the backscatter detector 22 outputs the pencil ray beam in the interval time period between adjacent transmission ray beams.

[0118] like Figure 3 As shown, the pulse frequency of the accelerator output transmission beam is 100 Hz, the pulse width is 3-5 μs, and the interval time between two adjacent pulses, that is, between two adjacent output transmission beams, is approximately 10 ms. Figure 3 The vertical line in the middle qualitatively indicates the relative size of the energy E of the transmitted ray beam output by the accelerator.

[0119] like Figure 2 and Figure 3 As shown, the rotating ring of the flying spot device 212 of the backscattered ray source 21 is provided with three beam holes 21221, and the rotation speed adopted is 2000rpm, that is, the time for one rotation is 30ms. The backscattered ray source 21 scans a column in 10ms. Taking the beam exit point G of the radiation source 211 as the center, the angle of the fan-shaped box is 90°, and the angle of the arc-shaped notch is 87°. Each beam hole 21221 passes through the arc-shaped notch of the fan-shaped box once, and there is a blind area with an angle of 3° without the output of the pencil ray beam. The time period when the beam hole 21221 passes through the arc-shaped notch of the fan-shaped box is the beam exit time period, and the time period when the beam hole 21221 passes through the blind area is the silent time period. Each time the backscattered ray source outputs the pencil ray beam, the beam exit time period is 9.67ms, and the corresponding silent time period is 0.33ms. In the silent time period of 0.33ms, the transmitted ray source 11 has no transmitted ray beam output, and the backscattered ray source 21 also has no pencil ray beam output. It can be understood that the relative size of the beam-emitting time period and the silent time period can be adjusted according to the angle of the arc-shaped notch of the fan-shaped box. Figure 3 In FIG. 1 , the shadows qualitatively indicate the relative magnitude of the energy E of the pencil beam output by the backscattered ray source 21 during the beam output time period.

[0120] The backscatter detector 22 collects the backscatter detection signal at a certain sampling interval in the interval between two pulses. The backscatter detection signal obtained in the silent period of 0.33ms is the afterglow signal of the silent period, and the backscatter detection signal obtained in the beam-out period of 9.67ms is the total signal of the superposition of the backscatter signal and the afterglow signal of the beam-out period.

[0121] In the embodiment of the present application, the backscatter signal correction device 30 fits the afterglow attenuation curve according to the backscatter detection signal obtained within the silent time period of 0.33ms, thereby obtaining the afterglow signal within the beam-out time period of 9.67ms, and forms a backscatter correction signal by subtracting the afterglow signal at the corresponding time point from the backscatter detection signal generated by the backscatter detector 22 within the beam-out time period of 9.67ms.

[0122] like Figure 4 As shown, the backscatter signal correction device 30 fits an afterglow attenuation curve according to the backscatter detection signal of the backscatter detector 22 in the silent period, and forms an afterglow signal according to the afterglow attenuation curve.

[0123] In this embodiment, the backscatter signal correction device 30 fits the afterglow attenuation curve multiple times and forms the afterglow signal according to the most recently fitted afterglow attenuation curve. Each time the transmission ray source 11 outputs a transmission ray beam and each time the backscatter ray source 21 outputs a pencil ray beam, the backscatter signal correction device 30 fits the afterglow attenuation curve once.

[0124] The afterglow decay curve is . Where t is the fitting time; I t is the afterglow signal at fitting time t; I 0 is the backscatter detection signal when the fitting time t is zero; τ is the decay time constant of the backscatter detector 22. τ can be calculated from the backscatter detection signals corresponding to multiple measurement times t during the silent period. Different types of detectors have different decay time constants.

[0125] That is to say, after the accelerator finishes emitting a transmitted ray beam, Figure 4 At time 0 in the figure, during the silent period before the backscatter ray source 21 emits a beam, the backscatter detector 22 collects data at a certain time interval, and the afterglow attenuation curve is fitted through the backscatter detection signal collected during the silent period. When the backscatter ray source 21 starts to emit a beam, the backscatter detection signal output by the backscatter detector 22 includes a backscatter signal and an afterglow signal. The afterglow signal fitted at the same time based on the fitting curve is subtracted from the backscatter detection signal in the beam emission time period to obtain the backscatter correction signal actually required. Figure 4The time t1 represents the start time of the backscattered ray source 21, and the time t2 represents the end time of the backscattered ray source 21. In this embodiment, t1 is 0.33 ms, and t2 is 10 ms.

[0126] Even if the fitted afterglow decay curve is used to deduct the afterglow signal, the fitted afterglow decay curve will inevitably have deviations compared to the actual afterglow signal. In this embodiment, a plastic scintillator or GAGG crystal is selected to form the backscatter detector 22, and the afterglow decay time is short, so that the final backscatter image is more realistic.

[0127] like Figure 1 As shown, the transmission image processing device 40 is signal-connected to the transmission detector 12 and is configured to form a transmission image according to the transmission detection signal.

[0128] like Figure 1 As shown, the backscatter image processing device 50 is signal-connected to the backscatter signal correction device 30 and is configured to form a backscatter image according to the backscatter correction signal.

[0129] The display device 60 is signal-connected to the transmission image processing device 40 and the backscatter image processing device 50 for displaying the transmission image and the backscatter image.

[0130] The control device 70 is connected to the transmission ray source 11 and the backscatter ray source 21 by signals, and is used to control the beam emission parameters of the transmission ray source 11 and the backscatter ray source 21. The beam emission parameters include, for example, beam emission time, beam emission frequency, and the like.

[0131] The control device 70 can be implemented as a general processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any appropriate combination thereof for performing the functions described in the present disclosure.

[0132] Figure 5 for Figure 1 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0133] like Figure 5 As shown, in this embodiment, the transmission ray source 11 is an accelerator, which outputs a transmission ray beam in a pulsed manner. The accelerator outputs a transmission ray beam in a high-low pulse interval manner, with the high pulse frequency and the low pulse frequency both being 200 Hz, and the pulse width being 3 to 5 μs. The interval time between adjacent high and low pulses is approximately 2.5 ms.

[0134] The rotating ring of the flying spot device 212 of the backscattered ray source 21 is provided with four beam holes 21221, and the rotation speed adopted is 6000rpm. The fan-shaped box is arranged concentrically with the rotating ring, and the angle of the fan-shaped box is 90°, so that the rotating ring of the flying spot device 212 can emit a pencil beam 4 times for each rotation of the rotating ring. The angle of the arc-shaped notch is 86°. Each beam hole 21221 passes through the arc-shaped notch of the fan-shaped box once, and there is a blind area with an angle of 4° without pencil beam output. The backscattered ray source 21 can complete a column of backscattering acquisition within the interval time period of 2.5ms between the adjacent high and low pulses emitted by the transmission ray source. Then the beam-emitting time period of each pencil beam is 2.39ms, and the corresponding silent time period in which neither the transmission ray source 11 nor the backscattered ray source 21 emits a beam is 0.11ms.

[0135] The backscatter detector 22 collects the backscatter detection signal at a certain sampling interval in the interval between two pulses. The backscatter detection signal obtained in the silent period of 0.11ms is the afterglow signal of the silent period, and the backscatter detection signal obtained in the beam-out period of 2.39ms is the total signal of the superposition of the backscatter signal and the afterglow signal of the beam-out period.

[0136] The backscatter signal correction device 30 fits the afterglow attenuation curve according to the backscatter detection signal obtained within the silent time period of 0.11ms, thereby obtaining the afterglow signal within the beam-out time period of 2.39ms, and forms a backscatter correction signal by deducting the afterglow signal at the corresponding time point from the backscatter detection signal generated by the backscatter detector 22 within the beam-out time period of 2.39ms.

[0137] Figure 5 For the parts not described in the corresponding embodiments, please refer to Figures 1 to 4 Related descriptions of the corresponding embodiments.

[0138] Figures 6 to 18 Taking multiple backscatter inspection devices forming multiple viewing angles as an example, a multi-viewing angle radiation inspection system integrating both transmission and backscattering radiation inspection technologies in some embodiments is illustrated.

[0139] Figure 6 This is a schematic diagram of the arrangement of a transmission inspection device and a backscatter inspection device relative to an inspection channel of a radiation inspection system of an embodiment of the present application, wherein the radiation inspection system includes one transmission inspection device and four backscatter inspection devices. Figure 7 for Figure 6 The schematic diagram of the timing of the transmission ray source 11 of the transmission inspection device of the radiation inspection system of the illustrated embodiment emitting a transmission ray beam and the pencil ray beam output by the backscatter ray source 21 of the backscatter inspection device 20.

[0140] like Figure 6 As shown, the radiation inspection system includes a transmission inspection device and four backscatter inspection devices. The transmission ray source 11 of the transmission inspection device is located on the right side of the inspection channel P, and the transmission detector 12 is located on the left side of the inspection channel P. The four backscatter inspection devices are respectively a first backscatter inspection device 20A located at a left perspective above the transmission detector 12 on the left side of the inspection channel P, a second backscatter inspection device 20B located at a right perspective above the transmission ray source 11 on the right side of the inspection channel P, a third backscatter inspection device 20C located at a top perspective above the inspection channel P, and a fourth backscatter inspection device 20D located at a bottom perspective below the inspection channel P.

[0141] The first backscatter inspection device 20A includes a first backscatter ray source 21A and a second backscatter detector 22A. The second backscatter inspection device 20B includes a second backscatter ray source 21B and a second backscatter detector 22B. The third backscatter inspection device 20C includes a third backscatter ray source 21C and a third backscatter detector 22C. The fourth backscatter inspection device 20D includes a fourth backscatter ray source 21D and a fourth backscatter detector 22D. The beam exit directions of the transmission ray beam emitted by the transmission ray source 11 and the pencil ray beam emitted by the backscatter ray sources of the backscatter inspection devices of each viewing angle are both toward the scanning channel P and perpendicular to the extension direction of the scanning channel P.

[0142] Figure 7 In the figure, the vertical line qualitatively indicates the relative size of the energy E of the transmitted ray beam output by the accelerator, and the shadow qualitatively indicates the relative size of the energy E of the pencil ray beam output by the backscattered ray source of each viewing angle in the beam-emitting time period. Furthermore, in order to distinguish the transmitted ray beam emitted by the transmitted ray source from the pencil ray beam emitted by the backscattered ray source of each viewing angle, the transmitted ray beam is marked as "transmitted", the pencil ray beam emitted by the first backscattered ray source 21A is marked as "backscattered 1", the pencil ray beam emitted by the second backscattered ray source 21B is marked as "backscattered 2", the pencil ray beam emitted by the third backscattered ray source 21C is marked as "backscattered 3", and the pencil ray beam emitted by the fourth backscattered ray source 21D is marked as "backscattered 4".

[0143] like Figure 7As shown, in this embodiment, between every two pulses of the accelerator serving as the transmission ray source 11, only the backscatter ray source of the backscatter inspection device at a certain viewing angle emits a beam, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the first backscatter ray source 21A, the second backscatter ray source 21B, the third backscatter ray source 21C and the fourth backscatter ray source 21D.

[0144] In this embodiment, each time the transmission ray source 11 outputs a transmission ray beam, the backscatter ray source 21 outputs a pencil ray beam, and the backscatter signal correction device 30 obtains an afterglow signal on site.

[0145] Figure 6 and Figure 7 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0146] Figure 8 for Figure 6 and Figure 7 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0147] like Figure 8 As shown, this embodiment and Figure 6 and Figure 7 The difference between the radiation inspection systems of the illustrated embodiments lies in the different beam emitting modes of the transmission ray source and the backscattered ray sources at each viewing angle.

[0148] Figure 8 In the illustrated embodiment, in order to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle, the radiation scan of the backscatter inspection device at two viewing angles is completed between the pulses of two transmitted ray beams, that is, within an interval time period, and the backscatter ray sources at each viewing angle emit beams in turn in the order of a first backscatter ray source 21A, a second backscatter ray source 21B, a third backscatter ray source 21C and a fourth backscatter ray source 21D.

[0149] In this embodiment, each time the transmission ray source 11 outputs a transmission ray beam, the backscatter signal correction device 30 acquires an afterglow signal on-site.

[0150] Figure 8 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0151] Fig. 9 for Figure 6 and Figure 7A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in another alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0152] like Fig. 9 As shown, this embodiment and Figure 6 and Figure 7 The difference between the radiation inspection systems of the illustrated embodiments lies in the different beam emitting modes of the transmission ray source and the backscattered ray sources at each viewing angle.

[0153] Fig. 9 In the illustrated embodiment, in order to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle, the radiation scan of the backscatter inspection device at four viewing angles is completed between the pulses of two transmitted ray beams, that is, within an interval time period, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the first backscatter ray source 21A, the second backscatter ray source 21B, the third backscatter ray source 21C and the fourth backscatter ray source 21D.

[0154] In this embodiment, each time the transmission ray source 11 outputs a transmission ray beam, the backscatter signal correction device 30 acquires an afterglow signal on-site.

[0155] Fig. 9 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0156] Fig.10 for Figure 6 and Figure 7 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in yet another alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0157] like Fig.10 As shown, this embodiment and Figure 6 and Figure 7 The difference between the radiation inspection systems of the illustrated embodiments lies in the different beam emitting modes of the transmission ray source and the backscattered ray sources at each viewing angle.

[0158] Fig.10 In the illustrated embodiment, in order to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle, the radiation scan of the backscatter inspection device at four viewing angles is completed between the pulses of two transmitted ray beams, that is, within an interval time period, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the third backscatter ray source 21C, the fourth backscatter ray source 21D, the second backscatter ray source 21B and the first backscatter ray source 21A.

[0159] Since the backscatter inspection devices at different viewing angles are set at different positions, the backscatter detectors at different viewing angles are affected differently by the afterglow of the transmission inspection device 10. The backscatter inspection device 20 least affected by the afterglow is started first, and the backscatter inspection device 20 most affected by the afterglow is started last, so that the backscatter inspection device 20 most affected can be given more afterglow decay time. That is, when multiple pencil beams are output within the interval time period of each adjacent transmission beam, the output order of the multiple pencil beams is arranged from the smallest to the largest influence of the afterglow signal of the transmission beam on the backscatter detector 22 receiving the pencil beam.

[0160] In this embodiment, the third backscatter detector 22C and the fourth backscatter detector 22D are located at the upper and lower sides of the transmission ray source 11, so the afterglow effect on the third backscatter detector 22C and the fourth backscatter detector 22D is relatively low. The relative height of the afterglow effect on the third backscatter detector 22C and the fourth backscatter detector 22D is affected by factors such as the distance from the transmission ray source in the height direction and the scanning angle of the transmission ray source. In this embodiment, the afterglow effect on the fourth backscatter detector 22D is higher than the afterglow effect on the third backscatter detector 22C. The second backscatter detector 22B is located on the same side of the transmission ray source 11, and will be affected by the afterglow of the backscattered rays generated after the transmission ray beam irradiates the inspected object, and the impact is higher than the fourth backscatter detector 22D and the third backscatter detector 22C, while the first backscatter detector 22A is located on the opposite side of the transmission ray source 11 and is affected by the afterglow of the transmission ray beam before or after attenuation, and is the most affected. Therefore, the order of emitting beams in turn according to the third backscattered ray source 21C, the fourth backscattered ray source 21D, the second backscattered ray source 21B and the first backscattered ray source 21A is more conducive to reducing the afterglow effect of the transmitted ray beam on the backscattered detectors at each viewing angle compared to other beam emitting orders.

[0161] In this embodiment, each time the transmission ray source 11 outputs a transmission ray beam, the backscatter signal correction device 30 acquires an afterglow signal on-site.

[0162] Fig.10 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0163] Fig.11 This is a schematic diagram of the arrangement of a transmission inspection device and a backscatter inspection device relative to an inspection channel of a radiation inspection system according to an embodiment of the present application, wherein the radiation inspection system includes a transmission inspection device and three backscatter inspection devices. Fig.12 for Fig.11The schematic diagram of the timing of the transmission ray source 11 of the transmission inspection device of the radiation inspection system of the illustrated embodiment emitting a transmission ray beam and the pencil ray beam output by the backscatter ray source 21 of the backscatter inspection device 20.

[0164] like Fig.11 As shown, the radiation inspection system includes a transmission inspection device and three backscatter inspection devices. The transmission ray source 11 of the transmission inspection device is located on the right side of the inspection channel P, and the transmission detector 12 is located on the left side of the inspection channel P. The three backscatter inspection devices are respectively a first backscatter inspection device 20A located at a left perspective above the transmission detector 12 on the left side of the inspection channel P, a second backscatter inspection device 20B located at a right perspective above the transmission ray source 11 on the right side of the inspection channel P, and a third backscatter inspection device 20C located at a top perspective above the inspection channel P.

[0165] The first backscatter inspection device 20A includes a first backscatter ray source 21A and a second backscatter detector 22A. The second backscatter inspection device 20B includes a second backscatter ray source 21B and a second backscatter detector 22B. The third backscatter inspection device 20C includes a third backscatter ray source 21C and a third backscatter detector 22C. The beam exit directions of the transmission ray beam emitted by the transmission ray source 11 and the pencil ray beam emitted by the backscatter ray sources of the backscatter inspection devices of each viewing angle are both toward the scanning channel P and perpendicular to the extension direction of the scanning channel P.

[0166] Fig.12 In the figure, the vertical line qualitatively indicates the relative size of the energy E of the transmitted ray beam output by the accelerator, and the shadow qualitatively indicates the relative size of the energy E of the pencil ray beam output by the backscattered ray source of each viewing angle in the beam-emitting time period. Furthermore, in order to distinguish the transmitted ray beam emitted by the transmitted ray source from the pencil ray beam emitted by the backscattered ray source of each viewing angle, the transmitted ray beam is marked as "transmitted", the pencil ray beam emitted by the first backscattered ray source 21A is marked as "backscattered 1", the pencil ray beam emitted by the second backscattered ray source 21B is marked as "backscattered 2", and the pencil ray beam emitted by the third backscattered ray source 21C is marked as "backscattered 3".

[0167] like Fig.12 As shown, in this embodiment, between every two pulses of the accelerator serving as the transmission ray source 11, only the backscatter ray source of the backscatter inspection device at a certain viewing angle emits a beam, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the first backscatter ray source 21A, the second backscatter ray source 21B and the third backscatter ray source 21C.

[0168] Fig.11 and Fig.12 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0169] Fig.13 for Fig.11 and Fig.12 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0170] like Fig.13 As shown, this embodiment and Fig.11 and Fig.12 The difference between the radiation inspection systems of the illustrated embodiments lies in the different beam emitting modes of the transmission ray source and the backscattered ray sources at each viewing angle.

[0171] Fig.13 In the illustrated embodiment, in order to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle, the radiation scan of the backscatter inspection device at three viewing angles is completed between the pulses of two transmitted ray beams, that is, within an interval time period, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the first backscatter ray source 21A, the second backscatter ray source 21B and the third backscatter ray source 21C.

[0172] Fig.13 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0173] Fig.14 for Fig.11 and Fig.12 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in another alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0174] like Fig.14 As shown, this embodiment and Fig.11 and Fig.12 The difference between the radiation inspection systems of the illustrated embodiments lies in the different beam emitting modes of the transmission ray source and the backscattered ray sources at each viewing angle.

[0175] Fig.14 In the illustrated embodiment, in order to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle, the radiation scan of the backscatter inspection device at three viewing angles is completed between the pulses of two transmitted ray beams, that is, within an interval time period, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the third backscatter ray source 21C, the second backscatter ray source 21B and the first backscatter ray source 21A.

[0176] In this embodiment, the third backscatter detector 22C is located above the transmitted ray source 11, so the third backscatter detector 22C is relatively less affected by the afterglow. The second backscatter detector 22B is located on the same side of the transmitted ray source 11, and will be affected by the afterglow of the backscatter rays generated after the transmitted ray beam irradiates the inspected object, and the impact is higher than the third backscatter detector 22C. The first backscatter detector 22A is located on the opposite side of the transmitted ray source 11 and is affected by the afterglow of the transmitted ray beam before or after attenuation, and is the most affected. Therefore, the third backscatter ray source 21C, the second backscatter ray source 21B and the first backscatter ray source 21A are used in turn to emit beams, which is beneficial to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle compared to other beam emission orders.

[0177] Fig.14 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0178] Fig.15 This is a schematic diagram of the arrangement of a transmission inspection device and a backscatter inspection device relative to an inspection channel of a radiation inspection system of an embodiment of the present application, wherein the radiation inspection system includes a transmission inspection device and two backscatter inspection devices. Fig.16 for Fig.15 The schematic diagram of the timing of the transmission ray source 11 of the transmission inspection device of the radiation inspection system of the illustrated embodiment emitting a transmission ray beam and the pencil ray beam output by the backscatter ray source 21 of the backscatter inspection device 20.

[0179] like Fig.15 As shown, the radiation inspection system includes a transmission inspection device and two backscatter inspection devices. The transmission ray source 11 of the transmission inspection device is located on the right side of the inspection channel P, and the transmission detector 12 is located on the left side of the inspection channel P. The two backscatter inspection devices are respectively a first backscatter inspection device 20A located on the left side of the inspection channel P above the transmission detector 12 and a second backscatter inspection device 20B located on the right side of the inspection channel P above the transmission ray source 11 and a second backscatter inspection device 20B located on the right side of the inspection channel P and a first backscatter inspection device 20A located on the left side of the inspection channel P and a second backscatter inspection device 20B located on the right ... first backscatter inspection device 20A located on the left side of the inspection channel P and a second backscatter inspection device 20B located on the right side of the inspection channel P and a second backscatter inspection device 20B located on the right side of the inspection channel P and a second backscatter inspection device 20A located on the left side of the inspection channel P and a second backscatter inspection device 20B located on the right side of the inspection channel P and a second backscatter inspection device 20B located on the right side of the inspection channel P and a first backscatter inspection device 20A located on the left side of the inspection channel P and a second backscatter inspection device 20B located on the right side of the inspection channel P and a second backscatter inspection device 20B located on the right side of the inspection channel P and a first backscatter inspection device 20A located on the left side of the inspection channel P and a second backscatter

[0180] The first backscatter inspection device 20A includes a first backscatter ray source 21A and a second backscatter detector 22A. The second backscatter inspection device 20B includes a second backscatter ray source 21B and a second backscatter detector 22B. The beam exit directions of the transmission ray beam emitted by the transmission ray source 11 and the pencil ray beam emitted by the backscatter ray sources of the backscatter inspection devices of each viewing angle are both toward the scanning channel P and perpendicular to the extension direction of the scanning channel P.

[0181] Fig.16In the figure, the vertical line qualitatively indicates the relative size of the energy E of the transmitted ray beam output by the accelerator, and the shadow qualitatively indicates the relative size of the energy E of the pencil ray beam output by the backscattered ray source of each viewing angle in the beam-emitting time period. Furthermore, in order to distinguish the transmitted ray beam emitted by the transmitted ray source from the pencil ray beam emitted by the backscattered ray source of each viewing angle, the transmitted ray beam is marked as "transmitted", the pencil ray beam emitted by the first backscattered ray source 21A is marked as "backscattered 1", and the pencil ray beam emitted by the second backscattered ray source 21B is marked as "backscattered 2".

[0182] like Fig.16 As shown, in this embodiment, between every two pulses of the accelerator serving as the transmission ray source 11, only the backscatter ray source of the backscatter inspection device at a certain viewing angle emits a beam, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the first backscatter ray source 21A and the second backscatter ray source 21B.

[0183] Fig.15 and Fig.16 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0184] Fig.17 for Fig.15 and Fig.16 A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in an alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0185] like Fig.17 As shown, this embodiment and Fig.15 and Fig.16 The difference between the radiation inspection systems of the illustrated embodiments lies in the different beam emitting modes of the transmission ray source and the backscattered ray sources at each viewing angle.

[0186] Fig.17 In the illustrated embodiment, in order to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle, the radiation scan of the backscatter inspection device at two viewing angles is completed between the pulses of two transmitted ray beams, that is, within an interval time period, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the first backscatter ray source 21A and the second backscatter ray source 21B.

[0187] Fig.17 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0188] Fig.18 for Fig.15 and Fig.16A schematic timing diagram of a transmission ray beam emitted by a transmission ray source 11 of a transmission inspection device and a pencil ray beam output by a backscatter ray source 21 of a backscatter inspection device 20 in another alternative embodiment of a radiation inspection system of the illustrated embodiment.

[0189] like Fig.18 As shown, this embodiment and Fig.11 and Fig.12 The difference between the radiation inspection systems of the illustrated embodiments lies in the different beam emitting modes of the transmission ray source and the backscattered ray sources at each viewing angle.

[0190] Fig.18 In the illustrated embodiment, in order to reduce the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle, the radiation scan of the backscatter inspection device at two viewing angles is completed between the pulses of two transmitted ray beams, that is, within an interval time period, and the backscatter ray sources at each viewing angle emit beams in turn in the order of the second backscatter ray source 21B and the first backscatter ray source 21A.

[0191] In this embodiment, the second backscatter detector 22B is located on the same side of the transmitted ray source 11, and will be affected by the afterglow of the backscattered rays generated after the transmitted ray beam irradiates the inspected object. The first backscatter detector 22A is located on the opposite side of the transmitted ray source 11, and is affected by the afterglow of the transmitted ray beam before or after attenuation, and is more affected than the second backscatter detector 22B. Therefore, the order of the second backscatter ray source 21B and the first backscatter ray source 21A emitting beams in turn is conducive to reducing the afterglow effect of the transmitted ray beam on the backscatter detectors at each viewing angle compared to other emitting beam orders.

[0192] Fig.18 For the parts not described in the corresponding embodiment, reference may be made to the relevant descriptions of other embodiments.

[0193] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present application can still be modified or some technical features can be replaced by equivalents, which should all be included in the scope of the technical solution requested for protection in this application.

Claims

1. A radiation inspection system having an inspection channel (P) for an inspected object to pass through, characterized in that: include: A transmission inspection device (10), comprising a transmission ray source (11) and a transmission detector (12) arranged on two opposite sides of the inspection channel (P), and configured to perform a transmission inspection on the inspected object passing through the inspection channel (P); and A backscatter inspection device (20), comprising a backscatter ray source (21) and a backscatter detector (22) arranged on the same side of the inspection channel (P), configured to perform a backscatter inspection on the inspected object passing through the inspection channel (P), wherein the time when the transmission ray source (11) outputs the transmission ray beam is staggered with the time when the backscatter ray source (21) outputs the pencil ray beam; a backscatter signal correction device (30) connected to the backscatter detector (22) by signal, and configured to deduct the afterglow signal generated by the transmitted ray beam output by the transmitted ray source (11) on the backscatter detector (22) from the backscatter detection signal generated by the backscatter detector (22) when the pencil ray beam is output, so as to form a backscatter correction signal; and The backscatter image processing device (50) is signal-connected to the backscatter signal correction device (30) and is configured to form a backscatter image based on the backscatter correction signal.

2. The radiation inspection system according to claim 1, characterized in that: The afterglow signal is formed according to pre-stored data pre-stored in the backscatter signal correction device (30); or The afterglow signal is acquired on-site according to the backscatter detection signal of the backscatter detector when the output of the transmitted ray beam stops and the pencil ray beam is not output when the radiation inspection system is working.

3. The radiation inspection system according to claim 2, characterized in that: The backscatter signal correction device (30) acquires the afterglow signal on-site multiple times and forms a backscatter correction signal based on the afterglow signal acquired on-site the most recently.

4. The radiation inspection system according to claim 3, characterized in that: Each time the transmission ray source (11) outputs the transmission ray beam, the backscatter signal correction device (30) acquires the afterglow signal on site once; or The flying spot device (212) of the backscattered ray source (21) comprises a fixed part (2121) and a movable part (2122) that moves periodically relative to the fixed part (2121), and the backscattered signal correction device (30) acquires the afterglow signal once on site each time the movable part (2122) moves one cycle.

5. The radiation inspection system according to claim 2, characterized in that: The transmission ray source (11) outputs the transmission ray beam in a pulsed manner; The backscattered ray source (21) outputs the pencil ray beam within an interval time period between adjacent transmitted ray beams; The backscatter signal correction device (30) obtains the afterglow signal on-site based on the backscatter detection signal in the silent time period when the backscatter detector (22) stops outputting the pencil ray beam except in the interval time period of the adjacent transmission ray beams.

6. The radiation inspection system according to claim 5, characterized in that: The backscattered ray source (21) comprises a radiation source (211) and a flying spot device (212); the flying spot device (212) comprises a fixed portion (2121) fixedly arranged relative to the radiation source (211) and a movable portion (2122) periodically moving relative to the fixed portion (2121); the flying spot device (212) is configured to output or stop outputting the pencil ray beam through relative movement of the fixed portion (2121) and the movable portion (2122).

7. The radiation inspection system according to claim 5, characterized in that: The backscatter signal correction device (30) fits an afterglow attenuation curve according to the backscatter detection signal of the backscatter detector (22) in the silent time period, and forms the afterglow signal according to the afterglow attenuation curve.

8. The radiation inspection system according to claim 7, characterized in that: The afterglow decay curve is: ,in, t is the fitting time; I t is the afterglow signal at fitting time t; I0 is the backscatter detection signal when the fitting time t is zero; τ is the decay time constant of the backscatter detector (22).

9. The radiation inspection system according to any one of claims 1 to 8, characterized in that: The transmission inspection device (10) and the backscatter inspection device (20) are configured so that the transmission ray beam and the pencil ray beam are coplanar.

10. The radiation inspection system according to any one of claims 1 to 8, characterized in that: The radiation inspection system comprises two or more backscatter inspection devices (20) with different viewing angles and / or two or more transmission inspection devices (10) with different viewing angles.

11. The radiation inspection system according to any one of claims 1 to 8, characterized in that: The pencil ray beam is output once or multiple times within the interval time of each adjacent transmission ray beam.

12. The radiation inspection system according to claim 11, characterized in that: Multiple pencil ray beams are output within the interval time of each adjacent transmission ray beam, wherein the output order of the multiple pencil ray beams is arranged from the smallest to the largest influence of the afterglow signal of the transmission ray beam on the backscatter detector (22) receiving the pencil ray beam.

13. The radiation inspection system according to any one of claims 1 to 8, characterized in that: The backscatter detector (22) comprises a plastic scintillator or a GAGG crystal.

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