WO2008031313A1

WO2008031313A1 - Multiple dr/ct detection device of containers

Info

Publication number: WO2008031313A1
Application number: PCT/CN2007/001954
Authority: WO
Inventors: Jigang An; Liqiang Wang; Zhifang Wu; Xincheng Xiang; Yisi Liu
Original assignee: Tsinghua University
Priority date: 2006-09-08
Filing date: 2007-06-21
Publication date: 2008-03-20
Also published as: WO2008031313A8; CN1916611A

Abstract

A multiple DR/CT detection device of containers relates to the field of nuclear technology application, and particularly to a digital radiography inspection technology for a large objects such as a container, a car or a missile, which is characterized in that arranging at least two gantries with detecting section along translational traction mechanism. The gantry can be a rotary gantry which rotatable or positioned in a given direction for obtaining the tomography images of the objects or the projection images of the objects along the given direction; or a fixed gantry which only positioned in a direction for obtaining the projection images of the direction; or a half-fixed gantry can positioned in a few direction; or any combination of the rotary gantry or the half-fixed gantry or the fixed gantry. The device is suitable to be used for nondestructive detection of a large objects such as a container, a car, a luggage and a missile, and to be used for the inspection of aviation containers or collective goods package also, to available exclude flammable and explosive articles to ensure safety of flight.

Description

Container multiple DR / CT detection device

The container multiple DR / CT detection device belongs to the field of nuclear technology applications, especially the digital radiation imaging detection technology for large objects such as containers, automobiles or missiles. Background technique

Container (large object) radiation imaging detection device using electron accelerator, radioisotope or X-ray machine as radiation source (such as France Schlumberger, Germany Hyman, British Aerospace and China's Beijing Hualixing Technology Development Co., Ltd. The product information of the company, as well as the US patents 4785168 and the Chinese patents 96102080.6 and 98101501.8, can basically meet the customs inspection requirements, but there are some defects, for example - only one or two fixed directions of the object to be inspected can be given. The radiation is projected into the fluoroscopic image, and once the device is built, the projection direction and the number of projections (1 or 2) can no longer be changed; only the radiation projection fluoroscopic image can be provided and the tomographic image of the object cannot be obtained.

Authorized Chinese invention patent ZL99110839.6 proposes a container DR / CT detection device using a radioisotope radiation source ( ^6Q Co or ¹³⁷ Cs), including a circular frame that can be rotated or fixed in a certain orientation, and can acquire the object A selected perspective (DR) image and a tomographic (CT) image of the specified location, and still use only one set of sources, detectors, and information systems. The device provides an important basis for discriminating the object material by means of the correspondence between the gray scale and the material density on the tomographic image.

However, the device described in the above patent (ZL99110839.6) only includes an annular frame for mounting the radiation source and the array detector, for example, to obtain a projected perspective image of a plurality of orientations of the object or a tomographic image of a certain portion. It is necessary to repeatedly shift the object and make the circular frame change orientation or repeat the rotation motion multiple times. This significantly reduces the detection efficiency (pass rate) of the number of objects that can be detected per unit time of the detection device. In the case of a large flow of goods, this situation is clearly not up to the requirements. Summary of the invention

The object of the present invention is to overcome the deficiencies of the container DR / CT detecting device described in the Chinese patent (ZL99110839.6), and propose a container (large object:) detecting device by setting up multiple (layer) rotating or fixed racks. The digital radiation projection fluoroscopic image of the object along multiple selected directions can be simultaneously obtained, and the tomographic radiation image of multiple parts of the object can be simultaneously obtained as needed, thereby significantly improving the detection capability and detection efficiency (passing rate) of the device.

The invention comprises a frame, a detecting component mounted on the frame, the detecting component comprises a radiation source, a shielding container, an irradiation chamber, a shielding valve, a collimator, an array detector, and a translational drag mechanism and a signal The processing system is characterized in that the racks on which the detecting components are mounted have at least two racks arranged along a translational drag mechanism.

The gantry is a rotating gantry that can be rotated or positioned in a set orientation for acquiring a guest tomographic image or a projected perspective image along a set orientation; or can only be positioned at a certain orientation to obtain a projection of the orientation A fixed frame of fluoroscopic image; or a semi-fixed frame that can be positioned in several orientations; or any combination of the rotating, fixed, and semi-fixed frames.

The number of the racks is 2 to 9.

The source of radiation in the detection component on the frame is a high specific activity ^6Q Co, ¹³⁷ Cs, ¹⁹² Ir or ⁷⁵ Se radioisotope with an activity of no more than 24 TBq.

The source of radiation in the detection component on the frame is an X-ray source.

The X-ray source can be an X-ray machine.

The X-ray source may be an electron accelerator X-ray source, and a leveler and a filter are sequentially disposed before the radiation source exit end.

The array detector is composed of a plurality of array detector unit arrays including pixel detector elements, wherein the array detector unit is a high-pressure gas-filled array ionization chamber, a multi-wire proportional chamber, a Geiger counter tube array, and a scintillation array detection. Or semiconductor array detector. The pixel detector of the array detector has a pixel size ranging from 2 mm to 40 mm and a square, rectangular or circular cross section. A ray trap is placed behind the array detector to absorb the radiation passing through the detector.

The test proves that the detection device proposed by the invention has high detection efficiency, can perform non-destructive testing of large objects such as containers, automobiles, packages and missiles, and can also be applied to detection of air containers and container packages, and can effectively eliminate Flammable and explosive materials ensure safe flight for greater inspection performance. DRAWINGS

Figure 1 is a perspective view of the container double loop DR / CT detecting device.

Figure 2 is a side elevational view of the container dual loop DR / CT detection device.

Figure 3 (a), 3 (b) is a state diagram of the container double-ring DR / CT detection device in the two ring frames when the detection components are positioned in the vertical direction and in the horizontal direction. detailed description

The main feature of the detecting device proposed by the present invention is that it contains two or more (including two) racks (suitable for 10 or less from the viewpoint of cost and the like), and the detecting member is fixedly mounted on the rack. The frame is rotatable for 180° to 360° rotation for acquiring object tomographic images, and can also be positioned at a set orientation for obtaining a projected perspective image of different parts of the object; or can only be positioned a fixed rack that acquires a projected perspective image of the orientation in a certain orientation; or a semi-fixed rack that can only be positioned in a certain orientation but does not have a continuous rotation function; or any combination of the three types of racks . The detecting device also includes a driving mechanism of a rotating frame or a semi-fixed frame, a container (guest) translation and drag mechanism, a signal acquisition and processing subsystem, a device operation control subsystem, and other conventional auxiliary facilities required, such as a camera. Fire monitoring and safety chain.

When the test is performed, the translational drag mechanism causes the object to be hooked straight along the axis of the frame. Line scan motion or position at a specific location. When the translational drag mechanism moves the object in a straight line, the fixed frame or the detecting component fixed on the rotating or semi-fixed frame of the set orientation can obtain the object along the direction according to the direction in which the object is positioned. Radiation projection perspective image (DR image). When certain designated parts of the object are positioned in the radiation area of the rotating gantry, the rotating gantry performs a rotational scanning motion, and the detecting component rotates the scanning frame to obtain a radiation tomographic image (CT image) of these parts. Users can consider the cost factors according to their needs, then determine the number and type of racks, arrange their order and orientation direction reasonably, and obtain the projected perspective images of different orientations and the tomographic images of different areas of the object.

Rotary rack

The rotating frame can be rotated from 180° to 360° to obtain the image of the guest tomographic image. It can also be positioned in the set orientation to obtain the projected perspective image of different parts of the object. The detecting component comprises a y radioisotope ray source and a shielding container thereof, an irradiation chamber, a shielding valve, a collimator, an array detector and a front end circuit, a ray trap, etc.; the ray source is a high specific activity with a line degree of only a few millimeters ^0Q Co, ¹³⁷ Cs, ¹⁹² Ir or ⁷⁵ Se radioisotope. The Cobalt-60 flaw detection source, which has been widely used in the industrial non-destructive testing industry, has an activity of less than 24 TBq, and is a preferred object, and is particularly suitable for the detection of large objects, which is advantageous for improving the reliability of the operation of the detecting device of the present invention. Rotating frames are generally annular rotating frames, the inner diameter of which should be large enough to allow large objects such as containers to pass easily and to be contained within a fan-shaped radiation field. The ray source may also use an X-ray source, such as an X-ray machine or an accelerator. The X-ray machine or the accelerator emits X-rays of continuous energy spectrum of different maximum energies. Except for differences in the components of the radiation source, the accelerator source is used. It is necessary to set up a "leveling device" for improving the spatial distribution of the ray and a "filter" for improving the X-ray energy spectrum. These "leveling devices" and "filters" are all utilizing the absorption of radiation by materials and the pair of high atomic number materials. The principle of stronger absorption of low-energy rays is an absorber of a certain material and shape. The structure of other aspects is basically unchanged. The array detector used is composed of a plurality of array detector units including a plurality of pixel detector elements, which can be a high pressure gas-filled array ionization chamber, a multi-wire proportional chamber, a Geiger counter tube array, and a flashing Array detectors (such as cesium iodide or cadmium dichromate scintillation crystals + photodiode array detectors) or semiconductor array detectors.

The translational drag mechanism of the detecting device is an electric motor vehicle, a roller conveyor belt, a belt conveyor belt or a chain plate transmission device that travels on the track for dragging the object for translational scanning motion. Various common and mature drag mechanisms can be used here to fully utilize the public knowledge in this technical field.

If the rack must have a 180° -360° rotation to obtain a tomographic image of a part of the object, the shape is generally circular.

Fixed rack

The fixed frame has the same structure as the rotating frame. The difference is that this can only be fixed in a certain position, so only the radiation projection perspective image of the object can be obtained.

Semi-fixed frame

It is only necessary to locate in several directions to obtain a radiation projection perspective image of a certain orientation, and the frame can be simplified into a "" shape, a "Π" shape or the like. It can be converted in several orientations, but does not have continuous rotation.

Further explanation will be given below with reference to the drawings.

As shown in 1 to 3, the detection device using two annular frames is taken as an example. The two annular frames are 5 and 5' respectively, and the detecting component is fixed on the frame 5, and the high specific activity is ⁶⁰ Co. ¹³⁷ Cs, ¹⁹² Ir or ⁷⁵ Se Y radioisotope radiation source and its container (with shielding valve) 1. Irradiation chamber and front collimator 2, rear collimator 3 and array detector 4 and matching front end circuit, etc. composition. They are respectively fixed to each other on the annular frame 5, and are capable of synchronously rotating in a random frame. The rear of the array detector 4 has a screen for absorbing the radiation passing through the detector Cover (called ray "trap"), which is a long strip of absorbent material, usually made of heavy metal material, the absorption of radiation depends on its thickness and material. Of course, it is also possible to help or replace the "trap" by building shielded walls or other protective equipment to prevent radiation from adversely affecting people or the external environment. The annular rotating frame 5 of the detecting device is fixed to the base 6 by a large bearing, and the base 6 is firmly placed on the embedded part in the foundation (the base portion buried in the ground in the figure is indicated by a broken line) ).

The ring frame 5' and its detecting parts are the same as the frame 5, and they are arranged one behind the other. The object to be inspected 7 (a large object such as a container, etc.) is placed on the translational drag mechanism 8, and can be moved at a specified speed in the direction of the axis of the circular rotating frame, or moved to a specified position by a ring. Rotate the rack 5 or 5' to complete the rotary scan operation. The drag mechanism 8 can be a motorized cart that travels on a track as shown, or can be a roller conveyor, a belt conveyor, a chain conveyor or other conventional general purpose conventional drag gear.

During the test, the shielding valve on the source container (1 and Γ) is opened to allow the gamma rays to exit through the slits in the irradiation chamber and the front collimator (2 and 1, :) and are collimated into a narrow sheet fan. Beam. The lenticular beam passes through the object 7 and passes through the rear collimators 3 and 3' (to remove the scattered rays) into the aligned array detectors (4 and 4'). The major portion of the radiation that is not absorbed by the detector will be blocked by the ray "trap" at the rear of the detector without adversely affecting the surroundings. Alternatively, shield walls or other protective equipment can be used to help or replace the “trap” to prevent radiation from adversely affecting people or the external environment. The rotary frame is an annular rotating frame whose inner diameter is large enough to allow large objects such as containers to pass easily and to be contained within a fan-shaped radiation field.

The source of radiation is a high specific activity ^6Q Co, ¹³⁷ Cs, ¹⁹² Ir or ⁷⁵ Se radioisotope with a line length of only a few millimeters. The cobalt-60 flaw detection source, which has been widely used in the industrial non-destructive testing industry, has an activity of less than 24 TBq, and is a preferred object, and is particularly suitable for the detection of large objects, which is advantageous for improving the reliability of the operation of the detecting device of the present invention. Γ-ray of ¹³⁷ Cs source The energy is 660 keV, which is only half of the energy of ^6Q CO Y-ray, and the corresponding penetration ability is much lower, but its half-life is longer (33 years), so the use period is much longer. The average energy of ¹⁹² Ir or ⁷⁵ Se gamma rays is about 300 keV, which is mainly suitable for light and small objects. Their half-life is much shorter than ^6Q Co, but the price is much cheaper.

The radiation source can also use an X-ray machine or a small electron accelerator that can generate high-energy X-rays. The X-ray energy emitted by the X-ray machine is relatively low. Even if the maximum energy reaches 400 keV, the penetration ability when detecting the object is only a few. Ten millimeters of iron, so it is mainly suitable for small and medium-sized and light objects. Electron accelerators produce higher-energy X-rays with a maximum energy of 9Mev or higher, which allows for higher penetration than ^6t) Co y-rays and is suitable for detecting large and heavy objects. However, the general accelerator structure is complicated, and it has a high-voltage power source, a magnetic field coil, and a microwave generator. There are relatively large difficulties in realizing the operation mode around the object rotation. Therefore, only a small, lightweight, and reliable dedicated accelerator designed and manufactured can be used to realize the detection mode of rotating around the object. Since the average energy of the ⁰⁽⁾ C ₀ ray has reached 1.25 MCV, the practical significance of using an accelerator with an average energy lower than it is not significant. The penetration capability of the developed small accelerator detection system should at least exceed that of the ^0Q CO Y-ray inspection system. Such a small accelerator that can rotate around the object can be used in the detection device of the present invention. Due to the complexity of the accelerator equipment, it is often difficult to rotate the ring frame continuously 360 °, and positive and negative rotation scanning can be used. When using an accelerator as a radiation source, in order to overcome the spatial non-uniformity of the output X-rays and adjust its energy spectrum, it is necessary to use a "leveling device" that relies on varying absorption thickness to suppress the radiation intensity in the forward direction and a low energy by means of heavy metals. A "filter" that strongly absorbs radiation (making the output X-ray energy spectrum tend to be high energy). After comprehensive consideration, it can be concluded that under the current conditions, for large objects, the radioisotope radiation source ^6Q Co or ¹³⁷ Cs is the preferred choice for the detection device of the present invention. In the case of small or medium-sized or light objects, a ¹⁹² Ir or ⁷⁵ Se radioisotope source can be used, or an X-ray source can be used. When a higher penetration power is required, it is necessary to use a miniaturized accelerator X-ray source that can rotate around the object.

The source container and the shielding valves 1 and 1' and the irradiation chamber and the front collimators 2 and 2' are made of a metal such as depleted uranium, lead or iron or an alloy thereof. The collimating slit on the front collimator collimates the gamma rays emitted by the source into a narrow sheet shape as shown in Fig. 1, and its opening angle in the direction perpendicular to the plane of the circular rotating frame is 0. Up to 1.0°, and the opening angle in the plane direction of the circular rotating frame is no more than 120°. The rear collimators 3 and 3' are made of a metal such as lead or iron or an alloy thereof, and the width of the collimating slit is equal to or slightly smaller than the pixel width of the array detectors 4 and 4', and is aligned with the front collimator. Collimation slit and active area of the source. The rear collimator, like the array detector, can be made into an arc centered on the active area of the source, and its arc length is such that it can completely contain the object by the illumination field defined by the array detector. Of course, it is also possible to design the rear collimator and the rear array detector into a linear shape, a fold line shape or the like as long as the irradiation field can accommodate the object.

The array detectors 4 and 4' are composed of a plurality of array detector units including a certain number of pixel detector elements, which are arranged in an arc shape (or linear, polygonal and other shapes) centered on the active area of the radiation source. The ray source, front collimator, rear collimator and array detector are mounted such that the collimated gamma rays are accurately incident into the sensitive volume of each pixel detector element. The array detectors 4 and 4' function to convert gamma rays that pass through the sensitive object into the sensitive volume and convert them into electrical signals. It requires high detection efficiency and sensitivity, is stable and reliable, and can withstand the vibration interference of the detecting component during the rotating scanning motion. The preferred array detector that can meet this requirement is the "gas ionization type high energy X, gamma radiation imaging array detecting device" described in Chinese patents ZL93102728.4 and ZL00121545.0. Other array detectors, such as multi-wire proportional chambers, proportional or gated tube arrays, scintillation detector arrays (such as cesium iodide or cadmium dichromate scintillation crystals + photodiode arrays) or semiconductor detector arrays, are also optional . According to different detection performance requirements, the cross-sectional dimensions of the pixel detector elements of the above various types of array detectors (like The size of the element is in the range of 2 mm to 40 mm, and the cross-sectional shape is square, rectangular, circular or other shape. The mass thickness of each pixel detector element along the direction of incidence of the radiation depends on the required detection efficiency. For example, when a scintillation crystal + photodiode detector array is used, the thickness of the cesium iodide or cadmium tungstate crystal may be selected from the range of 3 to 60 mm.

The array detector is usually mounted with the matching front-end circuit. After the output signal is amplified, analog-digital converted and acquired, it is processed by a computer to obtain a digital radiation projection perspective image or a digital radiation tomographic image of the object for inspection by the supervisor. , and can process and process information such as marking, sharpening, storing, printing, and transmitting.

The drag mechanism 8 is a motion mechanism that is independent of the circular rotating frames 5 and 5'. It is used to drag the object in the direction of the circular rotating frame axis to make a uniform linear motion at a specified speed, or to position the specified portion of the object in the scalloped sector-shaped irradiation area of the ray. The previous motion mode corresponds to the acquisition of the radiation projection fluoroscopic image, and the latter motion mode corresponds to the acquisition of the radiation tomographic image. For heavy objects, one of the options for the drag mechanism 8 is an electric trailer that moves on the track. These types of drag mechanisms can carry up to 40 tons or more, and can adapt to the detection needs of heavy and large objects such as full-load containers or giant missiles. The drag mechanism 8 can also be used with a roller or other type of conveyor belt. Regardless of the type of drag mechanism used, the area within the sheet-like radiation area should be as small and light as possible to reduce interference with the acquired radiation image. When using the roller type drag mechanism, care should be taken to leave a gap in the passage of the sheet beam to improve the quality of the tomographic image. Since the thickness of the sheet-shaped radiation irradiation area is only about 1 cm, this requirement is not difficult to achieve.

The two annular frames 5 and 5' shown in Figure 1 can be two rotating frames. When it is required to obtain a radiation projection perspective image of the object in a certain direction, the slinger detecting component is rotated along with the rotating frame. In a corresponding orientation, the object 7 is then passed through the sheet-like ray irradiation zone at a uniform speed by the drag mechanism 8, and simultaneously processes the signals output by the array detector. When the detecting components on the two annular frames are respectively positioned in different orientations, two radiation projection perspective images corresponding to two different directions of the object can be simultaneously obtained. In Figure 3 (a), 3 (b) show the state of the detecting device when the detecting members of the front and rear annular frames are in the vertical and horizontal directions, respectively. When it is necessary to obtain a radiation tomographic image of certain parts of the object, the slinger mechanism 8 moves the part to be detected by the object to be placed in the narrow sheet-shaped ray irradiation area, and then the detecting parts on the two annular frames are accompanied by the rack. By performing a 360° rotational scanning motion and simultaneously acquiring and processing the output signals of the array detectors 4 and 4', a radiation tomographic image of the two-part object can be simultaneously obtained. In the process of acquiring the tomographic image of the invention, the large object remains stationary, and the detecting component performs a rotational scanning motion along with the frame. This is necessary for containers or large missiles that are difficult to rotate.

In the double-loop structure detecting device shown in Fig. 1, it is also possible to make a frame (generally the front) a fixed frame or a semi-fixed frame in a set orientation (such as a vertical or horizontal orientation). To obtain a projected perspective image of the object, and another annular frame is a rotating frame, the frame is in a rotating scan state to obtain a tomographic image of a specified portion of the object. Or, first fix the two frames in different orientations (such as vertical and horizontal orientation). When the container moves through, the radiation projection perspective images of the two directions can be obtained at the same time, and the CT detection is determined according to the two images. The part is then returned to the proper position, and one or two annular frames are subjected to a rotary scanning motion to obtain a tomographic image of a certain part or at the same time.

If 3 or more racks are installed in the inspection device, you can set the number of rotating, semi-fixed or fixed racks and their matching methods as needed to make them more in the setting of the detection mode. Choose the room. More racks can guarantee higher detection efficiency (pass rate), and the combination of various combinations is easy to imagine, and there is no need to overcome more technical difficulties, so it will not be described again. The use of a radioisotope source such as ^6D Co significantly reduces the manufacturing cost of the "detection component." For modern manufacturing, the cost of a rotating or stationary rack is not high. Therefore, the added cost of adding a set of racks and matching "detection parts" is not very high, and it is urgent to mention High 捡 measurement efficiency (pass rate) is acceptable. Of course, the excessive number of racks is uneconomical, and it is generally suitable to use 10 or less, that is, the total number of racks is 2, 3, 4, 5, 6, 7, 8, or 9.

The outstanding advantage of the present invention is that by providing multiple (layer) racks and the proper combination of them, the detection efficiency (pass rate) of the detecting device is significantly (multiplied), thereby exerting greater inspection performance. A further advantage is that, regardless of the type of radiation source employed, during the acquisition of the tomographic image, the object remains stationary and the "detection component" is rotated for scanning motion. This is necessary for objects that are not suitable for turning, such as containers and large missiles.

The invention is applicable to the non-destructive operation of large objects such as containers, automobiles, packages and missiles. One application is to detect air containers or container packages at the airport, eliminate flammable and explosive materials, and ensure flight safety. Since it is possible to obtain a projected perspective image of a given direction and a tomographic image of a specified portion, it is advantageous for finding and determining suspicious objects. Thanks to the multiple (layer) design, the detection efficiency (pass rate) is greatly improved, and even if the airport business is busy, it can meet the demand.

One application is to inspect passing vehicles in customs, important departments, or in the entrances and exits of mass gatherings, and to provide more effective means of detecting terrorist attacks.

Another possible application is to inspect the defects of solid fuel inside large missiles to ensure the quality of the launch.

Two specific embodiments of the present invention are provided below - Example 1:

The invention designs a ^6Q Co dual (layer R / CT detecting device embodiment) suitable for an air container, and is described in detail below with reference to the accompanying drawings:

The overall structure of this embodiment is shown in FIG. The large guest double (layer) DR / CT radiation imaging detection system (referred to as "detection system") of this embodiment is installed in a circular rotation ⁶ on the rotating frame 5 and 5' ⁽³ Co source and its container and shielding valve 1 and Γ, irradiation chamber and front collimator 2 and 2', rear collimator 3 and 3 ', array detector and The traps 4 and 4' and the bases 6 and 6, the track plate type vehicle drag mechanism 8 and the signal acquisition and processing subsystem, etc. The source of the ray source is a ^0Q Co flaw detection source supplied by the market, and the activity is 100 curies. (3.7TBq) The irradiation chamber and the front collimator are respectively made of tungsten, depleted uranium, lead alloy or other heavy metals. The rear collimator is made of iron or lead alloy. The array detector is selected according to Chinese patents ZL93102728.4 and ZL00121545.0. The detection device, the pixel ionization chamber has a cross-sectional dimension of 7x7 mm, a total of 620. The active area of the source is a cylinder with a diameter of 4 mm and a length of 4 mm, and the distance from the center to the front surface of the array detector is 3.5 m. The inner diameters of the brackets 5 and 5' are both 3 m. The detecting part can be stepped (for example, one step per step) in the circular rotating frame, or can be continuously rotated at a constant speed. Roller type dragging The mechanism 8 has a load of 5 tons and a uniform linear motion speed of 6~18cm / sec o At the junction of the sheet beam and the drag system, the neutral between the rollers should be left to avoid interference with the radiation image. The detection device is suitable for detecting standard air containers with a width and height of about 1.6 m. Detecting passenger cars or cylindrical objects less than 2.5 meters in diameter.

When obtaining the radiation projection perspective image of the selected direction, the device can find a wire with a diameter of 2.5 mm or a piece of iron with a thickness of 0.7 mm after the 100 mm iron plate, and can still observe a resorber such as a lead block after the 220 mm iron plate. . When acquiring a tomographic image, the speculative index is closely related to the shape, size, material, structure, etc. of the object, and it is expected that defects of the order of millimeters can be found. In the area close to the density of water, the density resolution of this test device can reach 1% or better (the water can be easily separated from gasoline or alcohol).

Example 2:

The second ^6Q Co dual (layer) DR / CT detection device embodiment suitable for containers is the same as the first embodiment in the main aspect, but the array detectors 4 and 4' are not "array inflation ionization chambers" but instead use flashing Array detector - cesium iodide (cadmium tungstate) scintillation crystal + Photodiode array. Since the detection performance of such an array detector is similar to or slightly worse than the "array charge ionization chamber", the overall performance of the detection device is similar to or slightly worse than that of the embodiment 1. Industrial applicability

The container multiple DR/CT detecting device of the invention has high detection efficiency, can perform non-destructive testing of large objects such as containers, automobiles, packages and missiles, and can also be applied to detection of air containers and container packages, and can effectively Eliminate flammable and explosive materials and ensure safe flight for greater inspection performance.

Claims

Rights request

1. A container multiple DR/CT detecting device comprising a frame, a detecting component mounted on the frame, the detecting component comprising a radiation source, a shielding container, an irradiation chamber, a shielding valve, a collimator, an array detector, There is also a translational drag mechanism and a signal processing system, wherein the racks on which the detecting components are mounted have at least two, arranged along a translational drag mechanism.

2. A container multiple DR/CT detecting apparatus according to claim 1 wherein said frame is rotatable or positionable in a set orientation for obtaining a tomographic image or a projection perspective along a set orientation. a rotating frame of an image; or a fixed frame that can only be positioned in a certain orientation to obtain a projected perspective image of the orientation: or a semi-fixed frame that can be positioned in a certain orientation; or the rotary machine Any combination of racks, fixed racks, semi-fixed racks.

The container multiple DR / CT detecting apparatus according to claim 1 or 2, wherein the number of the racks is 2 to 9.

The container multiple DR/CT detecting apparatus according to claim 1 or 2, wherein the radiation source in the detecting means on the frame is high specific activity ^6Q Co, ⁱ³⁷ Cs, ¹⁹ or ⁷⁵ Se Radioisotope, its activity is not more than 24TBq.

The container multiple DR I CT detecting apparatus according to claim 1 or 2, wherein the radiation source in the detecting means on the frame is an X-ray source.

A container multiple DR / CT detecting apparatus according to claim 5, wherein said X-ray source is an X-ray machine.

The container multiple DR / CT detecting apparatus according to claim 5, wherein the radiation source is an electron accelerator X-ray source, and a leveler and a filter are sequentially disposed before the radiation source exit end.

8. A container multiple DR/CT detecting apparatus according to claim 1 The array detector is composed of a plurality of array detector unit arrays including pixel detector elements, wherein the array detector unit is a high-pressure gas-filled array ionization chamber, a multi-wire proportional chamber, a Geiger counter tube array, Scintillation array detector or semiconductor array detector.

9. The container multiple DR/CT detecting apparatus according to claim 8, wherein the pixel detector of the array detector has a pixel size ranging from 2 mm to 40 mm and a square, rectangular or circular cross section.

10. The detection container multiple DR I CT detecting apparatus according to claim 1, wherein a ray trap is disposed behind the array detector to absorb radiation passing through the detector.