WO1999018428A1 - Radiographic inspection apparatus - Google Patents

Abstract

A radiographic inspection apparatus comprises a radiation generation device and a radiation detection device disposed facing the radiation generation device with an object being inspected therebetween. In the case where the radiation detection device is constituted by a two-dimensional array detector, a light amplifying element is provided on the surface of the array detector facing that surface, on which radiation is incident, to lighten the radiographic inspection apparatus to achieve an increased mobility of the apparatus. Also, two kinds of collimators are provided and switched according to whether alignment work or photographing is performed so as to simplify alignment and reduce exposure during the alignment work. In the case where the radiation detection device is constituted by a unidimensional array detector, the collimators and the detector are constructed to be independently rotatable to achieve simplification of the alignment and reduction in exposure during the alignment work and simultaneously to enable selection of a scanning direction depending upon a type of structure to obtain a high quality transmission image for structures of different dimensions. Further, when the collimators move an irradiation field of radiation in synchronism with scanning of the unidimensional array detector, it is possible to perform irradiation of radiation only for a portion required for photographing and prevent unnecessary irradiation.

Description

 Specification

 Radiation inspection equipment Technical field

 The present invention relates to a radiation inspection apparatus, and more particularly to a technique effective for improving the mobility of the apparatus and reducing the radiation dose of radiation. Background art

It is necessary for traffic networks such as motorways and railroads to function reliably even in the event of a disaster such as an earthquake, in order to minimize the damage caused by the disaster and to promptly recover. In particular, elevated roads and railways are easily damaged by earthquakes, and the reliability of the piers is important. Non-destructive inspection means are required to ensure the reliability of these large structures, and inspection equipment that uses radiation such as high-energy X-rays generated by an electron beam accelerator is practical. One non-destructive inspection method using radiation is an X-ray transmission test using X-ray film (hereinafter, X-ray is used as a representative of radiation unless otherwise specified). This technique is based on the same principle as medical radiography, in which an X-ray film is placed behind the subject and the subject is irradiated with X-rays. The X-ray film is exposed according to the intensity of the X-ray transmitted through the subject. After the X-ray irradiation is completed, the X-ray film can be developed to obtain a transmitted image. In order to photograph a large structure using this method, it is necessary to first use a high-energy X-ray source using an accelerator or the like with a strong penetrating power, and it takes several 10 minutes to expose the X-ray film. Irradiation is required. In this case, it is necessary to install a large shield plate to prevent X-ray leakage to the surrounding area. This method is time-consuming and practical for all equipment installation, inspection, and withdrawal. I can't say.

 The apparatus disclosed in Japanese Patent Application Laid-Open No. 5-302997 uses a high-energy X-ray using an accelerator to form a 200-liter drum with metal chips and concrete inside. It is capable of inspection and has tomography and radiography functions (hereinafter referred to as the first conventional technology).

 Further, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 53-72673, there is no description about the collimator on the source side, but there is a description about a two-dimensional detector. In other words, as a means to obtain a two-dimensional transmission image, the two-dimensional distribution of radioactive objects with a small dose can be detected by providing an image intensifying means in a planar scintillator having afterglow. Conventional technology). As another technique, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 5-322802, there is no description about the collimator on the source side as in the above-mentioned technique. It is possible to obtain a magnified projected image and tomographic image. Also, there is disclosed a technique for matching the position of the X-ray focal point on the extension of the center line of the two-dimensional X-ray detector (hereinafter, referred to as a third conventional technique).

 The apparatus disclosed in Japanese Patent Application Laid-Open No. 5-253309 is used for treating a patient and obtaining a transmission image for confirming the position of the patient. The collimator on the source side is divided. A movable collimator is provided. When a transmitted image is obtained, the linear detector is moved and the movable collimator limits the irradiation field to the width of the linear detector (hereinafter referred to as the fourth section). Of the prior art). Disclosure of the invention

For inspections in urban areas where most bridges and piers are located, a huge number of inspections are required. It is necessary to reduce the leakage dose because of the mobility of the equipment required for the inspection, that is, weight reduction and consideration for the surrounding environment. Furthermore, it is desirable that the radiation generator and the radiation detector are separated in order to accommodate various dimensions and forms. For this reason, a simple means of alignment between the radiation generator and the radiation detector is required. It is necessary to reduce the amount of radiation provided during the alignment work, as well as to reduce the amount of leakage during imaging. Satisfying all of these will affect practical application.

 Here, we summarize the conditions required for local inspection equipment, such as in an urban area,

(1) Equipped with a high-energy X-ray generator using an electron beam accelerator to generate X-rays with strong penetration power. (2) X-ray generation to reduce leakage of X-rays to the surrounding environment (3) Equipped with a high-sensitivity solid-state detector (semiconductor detector, scintillation detector, etc.) and a signal processing device to complete the inspection in a short time. In order to evaluate in a short time, an image display and processing device mainly composed of a computer is provided. (5) Installation and removal can be performed in a short time. The inspection device targeted by the present invention can be configured with two-dimensional and one-dimensional detectors, and uses a collimator on the source side corresponding to each detector to prevent unnecessary radiation irradiation. I do. The collimator on the source side is used to prevent X-ray irradiation outside the effective range of the detector.

In a device using a two-dimensional detector, a collimator having a conical opening (hereinafter referred to as a cone beam collimator) or a collimator having a pyramid-shaped opening (hereinafter referred to as a horn beam collimator) Use In an apparatus using a one-dimensional detector, it is desirable to use a collimator having a fan-shaped opening (hereinafter referred to as a fan beam collimator). However, since the one-dimensional detector is scanned to obtain a two-dimensional transmission image, scanning of the detector is performed. It is necessary to move the irradiation position of the fan beam collimator in synchronization with the inspection. Here, the problems of the above-described device using the two-dimensional array detector and the device using the one-dimensional array detector are summarized. The first issue related to the equipment using the two-dimensional array detector is to reduce the weight of the equipment, especially the weight of the two-dimensional array detector radiation detector, in order to improve mobility. . The second problem is to provide a simple means for arranging a two-dimensional array detector type radiographic inspection apparatus and to reduce the irradiation dose. The third issue related to the equipment using the one-dimensional array detector is to provide a simple means of aligning the one-dimensional array detector type radiological inspection equipment and to reduce the irradiation dose. is there.

 In the first and fourth prior arts described above, it is premised that the radiation generator and the radiation detector are installed on a common base or installed and fixed, and the alignment is performed separately. It is not expected to do so.

Consider a large structure, for example a pier with a depth of 1 meter, and choose 1 meter angle as the effective inspection range of the equipment. At this time, if the distance between the focal point of the radiation source and the two-dimensional array detector is 4 meters, the effective range of the detector is required to be about 2 meter angle. It differs slightly depending on the position). In the second prior art, an optical amplifier such as a micro-channel plate is used. However, it is extremely difficult to integrally manufacture the optical amplifier to have the above-mentioned effective range. Hang on. Further, in the third prior art, since a large number of optical fibers are used, the weight of the radiation detection device is increased, and the size of the radiation detection device is increased, and the mobility is reduced. Furthermore, it is very costly to connect to individual scintillators. In an on-site alignment, both the radiation generator and the radiation inspection device may not be able to see through the test object at all, and it is necessary to perform alignment even in this state.

 The present invention has been made in view of the above background,

 A first object of the present invention is to provide a two-dimensional array detector type radiographic inspection apparatus, in particular, to provide a radiation inspection apparatus that is lightweight and highly mobile.

 A second object of the present invention is to provide a simple arrangement for separating a radiation generator and a radiation inspection apparatus.

 Further, a third object of the present invention is to provide a radiation inspection apparatus capable of reducing the irradiation dose during alignment work.

 According to a first aspect of the present invention, in a two-dimensional array detector type radiographic inspection apparatus, according to a first aspect of the present invention, there is provided a radiation generator and radiation arranged at a position facing each other across an inspection body. In a radiation inspection apparatus including a detection device, the radiation detection device includes a two-dimensional array detector, and includes an optical amplification element on a surface of the array detector facing a radiation incident surface.

 According to a second feature of the present invention, in a two-dimensional array detector type radiographic inspection apparatus, in order to achieve the second and third objects, according to a second aspect of the present invention, the radiation generation apparatus is located at a position facing the radiation generator with the inspection object interposed therebetween. A radiation inspection apparatus comprising a radiation detector using a two-dimensional array detector to be arranged, comprising: an adjustment collimator having one or more pinholes or slits at a radiation outlet of the radiation generator; and the two-dimensional array detection. A collimator for imaging that irradiates in accordance with the effective range of the instrument is provided and switched.

In the one-dimensional array detector type radiation inspection system, the second and third eyes According to a third aspect of the present invention, there is provided a radiation generator having a beam collimator at a radiation exit, and a one-dimensional array detection device arranged at a position opposed to the inspection object. In a radiation inspection apparatus comprising a radiation detector using a detector, scanning of the one-dimensional array detector with an adjustment collimator having one or more pinholes or slits at a radiation outlet of the radiation generator is performed. The collimator for imaging that performs irradiation corresponding to the effective range included is switched, and the one-dimensional array detector rotates about the central axis of the cone beam. It is desirable to rotate each independently by 90 ° or more.

 According to a fourth aspect of the present invention, in a one-dimensional array detector-type radiographic inspection apparatus, according to a fourth aspect of the present invention, a radiation generator including a fan beam collimator at a radiation outlet; In a radiation inspection apparatus comprising a radiation detection apparatus using a one-dimensional array detector arranged at a position facing the inspection object and having a function of scanning in an array direction of the array detector and in a direction perpendicular to the array detector, The fan beam collimator and the one-dimensional array detector rotate about the central axis of the fan beam, and the fan beam collimator moves the irradiation field of the fan beam in synchronization with the scanning of the one-dimensional array detector. It is desirable that the rotation be independently 90 ° or more.

According to a fifth aspect of the present invention, in a one-dimensional array detector type radiographic inspection apparatus, according to a fifth aspect of the present invention, there is provided a radiation generating apparatus having a radiation collimator at a radiation exit. A radiation inspection apparatus comprising: a radiation detector that uses a one-dimensional array detector arranged at a position facing an inspection object with the one-dimensional array detector interposed therebetween, and has a function of scanning in the direction perpendicular to the array direction of the array detector. In one embodiment, the fan beam collimator and one-dimensional array detection And the radiation generator rotates the fan beam around the central axis of the fan beam (desirably rotates independently by 90 ° or more), and the radiation generator synchronizes with the scanning of the one-dimensional array detector. Translate or rotate to move through the irradiation field.

 According to a first feature of the present invention, an optical amplifying element is mounted on a light extraction surface of an array scintillator. By configuring the optical amplifying element with, for example, an organic multilayer film, the optical amplifying function can be realized with a very slight increase in weight. In addition, thin film forming techniques such as vapor deposition can be used, and a large number of scintillators can be processed at one time.

 According to the second feature of the present invention, when performing alignment, an adjustment collimator having one or more pinholes or slits is attached to the radiation outlet of the radiation generator. Since the irradiation pattern from the adjustment collimator is known, the relative positional relationship between the two can be obtained by comparison with the pattern detected by the two-dimensional detector, and the correction amount required for the alignment is determined from the result. When the alignment work is completed, switch to the collimator for shooting.

 The pinholes in the adjustment collimator provide the reference pattern required for alignment and prevent unnecessary irradiation.

According to the third feature of the present invention, similar to the second feature, when performing alignment, an adjustment device having one or more pinholes or slits at the radiation outlet of the radiation generator is provided. Attach the collimator. Since the irradiation pattern from the adjustment collimator is known, the relative positional relationship between the two can be obtained by comparison with the two-dimensional detection pattern obtained by scanning the one-dimensional detector. The amount of correction required for is determined. When the alignment work is completed, switch to the collimator for photographing. The adjustment collimator pinholes or slits provide the necessary reference pattern for the alignment and prevent unnecessary illumination.

 Furthermore, the scanning is performed by rotating the one-dimensional array detector about the center axis of the cone beam and moving the slit adjustment collimator 90 ° between the slit direction and the array detector array direction. Determine the amount of correction required for alignment without doing this. For example, first, the slit obtains the horizontal position correction amount from the detection pattern of the one-dimensional array detector with respect to the vertical direction. Next, the slit obtains the position correction amount in the vertical direction from the detection pattern of the one-dimensional array detector with respect to the horizontal. The correction amount necessary for real alignment is determined by these two irradiations.

 Further, by scanning the one-dimensional array detector while rotating, the scanning direction is selected according to the shape of the inspection object or the situation of the imaging location.

According to the fourth aspect of the present invention, the fan beam collimator plays a role similar to that of the slit adjusting collimator described above. Therefore, the one-dimensional array detector is rotated about the center axis of the fan beam, and the direction of the thin and wide fan beam (hereinafter referred to as the fan direction) is shifted 90 ° from the direction of the array of the array detector. This determines the amount of correction required for the alignment without scanning. For example, first, the radiation direction is applied with the fan direction vertical and the array direction of the one-dimensional array detector horizontal, and the detection pattern from the one-dimensional array detector is obtained. The position correction amount in the horizontal direction is obtained from this detection pattern. Next, radiation is emitted with the fan direction horizontal and the array direction of the one-dimensional array detector vertical to obtain the detection pattern from the one-dimensional array detector. A horizontal position correction amount is obtained from this detection pattern. Less than Above, the amount of correction required for the alignment is determined by two irradiations.

 In addition, the fan beam collimator provides the necessary reference pattern for the alignment and prevents unnecessary irradiation during the alignment.

 Furthermore, by moving the irradiation field of the fan beam in synchronization with the scanning of the one-dimensional array detector, radiation is irradiated only to a portion required for imaging, and unnecessary irradiation is prevented.

 Further, by scanning the one-dimensional array detector while rotating, the scanning direction is selected according to the shape of the inspection object or the situation of the imaging location.

 According to the fifth aspect of the present invention, similarly to the fourth aspect, both the fan-beam collimator and the one-dimensional array detector are independently rotated to obtain the detection pattern of the one-dimensional array detector. This determines the amount of correction required for real alignment.

 The fan beam collimator also provides the necessary reference pattern for the alignment and prevents unnecessary irradiation during the alignment.

Furthermore, the central axis of the radiation generated from the target and the central axis of the fan beam collimator are made to substantially coincide, and the irradiation field of the fan beam collimator is moved in synchronization with the scanning of the one-dimensional array detector. The radiation generated from the target has the property that the intensity is higher at the middle L axis and lower at the periphery. Therefore, when operating only the fan beam collimator, if the fan beam collimator is oriented away from the center axis, the weak part of the radiation will be used. Reduce the resolution slightly. Therefore, the center axis of the radiation generated from the target and the center axis of the fan beam collimator should be almost coincident to move the irradiation field of the fan beam collimator in synchronization with the scanning of the one-dimensional array detector. "io- prevents the resolution from deteriorating in the peripheral area. The above operation can be achieved by rotating or translating the entire radiation generating apparatus in synchronization with the one-dimensional array detector. However, this can also be achieved by operating the target and the fan beam collimator in the same way, however, in this case, the electron beam is bent by bending the electron beam traveling direction of the accelerator before the target. They should collide at approximately the same angle at approximately the same location on the get.

 In addition, by moving the irradiation field of the fan beam in synchronization with the scanning of the one-dimensional array detector, radiation is irradiated only to a portion necessary for imaging and unnecessary irradiation is prevented.

 In addition, by scanning the one-dimensional array detector while rotating, the scanning direction is selected according to the shape of the inspection object or the situation of the imaging location. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a perspective view schematically showing a two-dimensional array detector type radiation detector according to one embodiment of the present invention.

 FIG. 2 is a perspective view showing a radiation inspection apparatus according to one embodiment of the present invention. FIG. 3 is a configuration diagram showing a radiation inspection apparatus according to one embodiment of the present invention. FIG. 4 is a configuration diagram showing a light amplification section of an array detection element constituting a two-dimensional array detector according to one embodiment of the present invention.

 FIG. 5 is a configuration diagram showing a detection element for an array constituting a two-dimensional array detector according to one embodiment of the present invention.

FIG. 6 is a configuration diagram showing a method of supplying power to the array detection element according to one embodiment of the present invention. FIG. 7 is a configuration diagram showing a detection element for an array constituting a two-dimensional array detector according to one embodiment of the present invention.

 FIG. 8 is a perspective view showing a source-side collimator of one embodiment of the present invention, and FIG. 9 is a contour graph showing a two-dimensional detector output of one embodiment of the present invention.

 FIG. 10 is an explanatory diagram showing a method for correcting the influence of a test object on a two-dimensional detector output according to one embodiment of the present invention.

 FIG. 11 is a configuration diagram showing a scanning mechanism and a rotation mechanism of the one-dimensional detector type inspection apparatus according to one embodiment of the present invention.

 FIG. 12 is a configuration diagram showing a scanning mechanism and a rotation mechanism of the one-dimensional detector type inspection apparatus according to one embodiment of the present invention.

 FIG. 13 is a configuration diagram showing a scanning mechanism of the one-dimensional detector type inspection apparatus according to one embodiment of the present invention.

 FIG. 14 is an explanatory view showing an alignment method in the one-dimensional detector type inspection apparatus according to one embodiment of the present invention.

 FIG. 15 is a graph showing a one-dimensional detector output of one embodiment of the present invention.

 FIG. 16 is an explanatory diagram showing a method for correcting the influence of a test object on a one-dimensional detector output according to one embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view schematically showing a two-dimensional array detector type radiation detector according to one embodiment of the present invention. An electron accelerator is used as the source for inspecting large structures. The radiation generated there is very strong and has a large structure. This is an indispensable requirement for inspection of structures. However, the high penetrating power makes it difficult to detect the radiation. Therefore, in this apparatus, the array detecting element 21 uses a deep scintillator 211. Here scintillation Ichita usable may if it has a function of emitting fluorescence by irradiation, N al (T l) crystal, C DW_〇 ₄ crystals, Z NW_〇 ₄ crystal, B i ₄ G e ₃ 〇 _{1 There are two} crystals, plastic scintillator to which a fluorescent substance is added, etc., but there is no particular limitation. The elements are arranged vertically and horizontally to form a two-dimensional array detector with the required effective range. The light from the scintillator 211 is amplified by the optical amplifier element 212 where it exits on the side opposite to the radiation incident direction. Then, the two-dimensional imaging device 3 receives the light from each of the array detection devices 21. The optical amplifying element 212 is composed of an organic multilayer film, which will be described later, or a hybrid type element of a light receiving element, an amplifying element, and a light emitting element, thereby enabling weight reduction and cost reduction by mass production. FIG. 2 is a perspective view showing a radiation inspection apparatus according to one embodiment of the present invention. Bridges of elevated roads have various sizes and structures. Therefore, considering that it can be used without limiting the shooting target. It is desirable to separate radiation generator 1 and radiation detector 2. Furthermore, since inspections are often performed in a state where both parties cannot see through, alignment means is required in a state where both parties cannot see through. In addition, when the imaging target is in an urban area, measures to prevent radiation from leaking to the surrounding area are desired, and it is important to prevent unnecessary radiation during alignment and during imaging. FIG. 3 is a configuration diagram showing a radiation inspection apparatus according to one embodiment of the present invention. Align radiation generators and radiation detectors with the imaging target, such as a bridge, in between. High-energy radiation with a strong penetrating power is accelerated by the electron beam accelerator 11 and collided with the target 12, and is emitted based on the principle of bremsstrahlung radiation. Live. The radiation (X-rays) generated here has a directivity in front but is widely generated, so the collimator 13 is attached to the tip of the target 12 to limit the irradiation field. The irradiation field of the collimator 13 roughly corresponds to the effective range of the detector of the radiation detection device to prevent unnecessary irradiation. The collimator is preferably made of a material that efficiently absorbs unnecessary radiation, such as lead and tungsten alloy, but is not particularly limited. The radiation generator, which includes an electron beam accelerator, a target, and a collimator, performs attitude control such as translation and rotation by a drive unit 14.

 The signal from the one-dimensional or two-dimensional array detector 21 is converted into digital data by a signal processor 22. The digital data is calculated by a computer 41 and necessary image processing is performed, and a result such as a transmission image is displayed on a display 42. In addition, recording and printing are performed by recording means and printing means (not shown) as necessary. The radiation detecting section composed of the array detector 21 and the signal processing device 22 controls the attitude such as translation and rotation by the driving device 24.

FIG. 4 is a configuration diagram showing a light amplification section of an array detection element constituting a two-dimensional array detector according to one embodiment of the present invention. The optical amplifier consists of an optical-to-electron converter 215, a carrier transporter 216, an electron-to-optical converter 216, and electrodes 213 on both sides. The light from the scintillator 211 enters the photoelectron conversion unit 215 through the electrode 213 directly or by reflection and scattering on the inner surface of the scintillator, and generates electric charge. The generated charges move due to the electric field applied between the electrodes, and enter the electron-light converter 216. Here, the charge becomes light again, and the light passes through the carrier transporter 217 and exits through the electrode 213. Here, in order to perform optical amplification as a whole, it is necessary to provide an amplification function in one or both layers of the photo-electron converter and the electronic-optical converter. is necessary. Such a function is described, for example, in the Journal of the Japan Society of Applied Physics, Vol. 64, No. 10 (1995), p. Things can be used. In this paper, we used a photoconductive perylene pigment, a naphthalene derivative, and a phthalocyanine pigment as the photo-electron conversion unit 215, and used t-Bu Ph-PTC as the electron-light conversion unit 216. A 1 q ₃ is used.

 As a whole, to further increase the light-to-light amplification factor, it is possible to stack the above-described light amplification layers a plurality of times, although not shown.

FIG. 5 is a configuration diagram showing a detection element for an array constituting a two-dimensional array detector according to one embodiment of the present invention. The structure is the same as described in FIG. Here, a method for extending the electrode 2 13 to the side surface of the scintillator 2 11 will be described. For example, the electrode 2 13 on the scintillator side is formed over any one of the side surfaces adjacent to the surface opposite to the radiation incident surface. Next, the photo-to-electron converter 2 14, the electron-to-optical converter 2 15, and the carrier transporter 2 16 are sequentially stacked. After that, an insulating layer 214 is formed except for a light exit. Lastly, the electrodes 2 13 are formed over the insulating layer from the light exit to any surface from the side of the scintillator other than the first electrode. The bias is applied to the optical amplifier using the electrode on the side surface of the scintillator. FIG. 6 is a configuration diagram showing a method of supplying power to the array detection element according to one embodiment of the present invention. Power supply leads 218 are attached to both sides of the insulating substrate 219, and insertion holes corresponding to the positions of the array detection elements 21 are provided. As described above, if electrodes are formed on the side surfaces of the scintillator, power can be supplied to the optical amplifier via the leads 218. The lead contacts the electrode on the side surface of the scintillator with a required pressure and is electrically connected, and is not particularly limited to the illustrated shape. FIG. 7 is a configuration diagram showing a detection element for an array constituting a two-dimensional array detector according to one embodiment of the present invention. The same function can be achieved by combining a plurality of functional elements by hybrid, in addition to realizing the optical amplifier section by the organic multilayer film as shown in FIG. For example, the light-receiving element 253 is mounted on one side of the flexible substrate, and the amplifying element 254 and the light-emitting element 255 are mounted using the back side. The signal from the light receiving element 25 3 can be connected to the amplifying element 2 54 on the opposite side by using the through hole pattern of the flexible board 25 1. The same applies to the connection between the amplifying element 255 and the light emitting element 255. The light receiving element 25 3 is attached to the scintillator 2 11 with an optical adhesive 2 52. By extending the pattern of the power supply line formed on the flexible substrate to the side surface of the scintillator, power can be supplied to each element by, for example, the method shown in FIG.

 FIG. 8 is a perspective view showing a source-side collimator according to one embodiment of the present invention. If the positions of the radiation generating device 12 and the radiation detecting device 26 are shifted from each other, the resolution decreases, such as chipping or blurring in the transmitted image. Therefore, an alignment is required before shooting. In the alignment work, for example, an adjustment collimator 13 1 with one pinhole is installed at the center. When measurement is performed in this state, a pattern that comes out of the pinhole, that is, an output appears only at one point, and by specifying the location, the mutual positional relationship can be easily determined. Based on this, the radiation generator 12 and the radiation detector 26 are aligned. The adjustment collimator must have a specific pattern, as described above, even if it has multiple pinholes or one or more slits in addition to one pinhole at the center. good.

When the alignment work is completed, switch to the collimator for shooting 1 3 2 To shoot. Although the switching mechanism is not shown, a sliding type or rotary type may be considered.

 FIG. 9 is a contour graph showing a two-dimensional detector output of one embodiment of the present invention. It is an output image from a two-dimensional detector in the case of the pinhole collimator described above. From this result, the position correction amount of the alignment, for example, ΔX and ΔΥ are determined. Although not shown, the position is corrected by the attitude control means of one or both of the radiation generator and the radiation detector. After the correction, the measurement may be performed again to confirm that the position correction is performed normally. FIG. 10 is an explanatory diagram showing a method for correcting the influence of a test object on a two-dimensional detector output according to one embodiment of the present invention. In general, an ideal pattern is not always obtained due to the influence of the inside of the subject on the detector output of the pinhole collimator.For example, an internal structure such as a steel frame is almost at the center of the pinhole. When the pattern is included, ideally, a concentric contour pattern is obtained, and one half of the pattern becomes distorted. This is due to the fact that the distorted side causes the radiation intensity to decrease due to the internal steel frame, and it is impossible to predict in advance unless the internal shape is accurately grasped. However, for example, by measuring the source intensity at a known different intensity, two or more detector output patterns are acquired, and, for example, by displaying the logarithmic difference between the two, the internal structure of the test object is displayed. The effect on the test results can be corrected.

FIG. 11 is a configuration diagram showing a one-dimensional detector including a source-side collimator and its periphery of a one-dimensional detector type inspection apparatus according to one embodiment of the present invention. The shape of the slit of the collimator 144 on the side of the radiation source 12 is determined in accordance with the shape of the translatable sensitive part of the one-dimensional array detector 27 rotatable by the driving device 28. The sensitive part has a structure capable of translating within the array detector 27 (The same applies to Fig. 12, Fig. 13, and Fig. 14.) At this time, the mutual distance between the radiation generator and the radiation inspection device affects the dimensions of the slit. You need to choose. Alternatively, although not shown, the slit shape is made variable and adjusted optimally according to the conditions at the shooting site. The operating direction of the detector may not always be the same due to the shape of the test object and surrounding conditions. Also, there is an optimal scanning direction depending on the internal shape of the inspection object. In order to arbitrarily set the scanning direction during imaging, both the source 12 and the detector 27 are rotated in the same manner.

 The procedure of alignment with this device will be described later (Fig. 14).

FIG. 12 is a configuration diagram showing a scanning mechanism and a rotation mechanism of the one-dimensional detector type inspection apparatus according to one embodiment of the present invention. In the radiation generator 11, the central axis of the radiation generated from the target and the central axis of the fan beam collimator 142 are substantially coincident with each other, and the fan beam is synchronized with the one-dimensional array detector 27 scanning. The irradiation field of the collimator is moved by the driving device 14 on the source side. The radiation generated from the target has the property that the intensity increases toward the center axis and decreases toward the periphery. Therefore, when operating only the fan beam collimator 1 2, if the fan beam collimator 1 4 2 is directed away from the central axis, the radiation weak part is used, and the imaging result , The resolution of the peripheral portion is slightly reduced. Therefore, the center axis of the radiation generated from the target and the center axis of the fan beam collimator are almost aligned, and the irradiation field of the fan beam collimator is moved in synchronization with the scanning of the one-dimensional array detector. To prevent the resolution from deteriorating at the periphery. Since the drive device 14 on the source side should make the irradiation field of the fan beam collimator 12 almost coincide with the movable sensitive part of the one-dimensional array detector 27, the entire radiation generator is primary. Synchronizes with the original array detector It can also be achieved by performing parallel movement. The drive device 14 allows the fan beam collimator 14 2 and the drive device 28 to independently rotate the three-dimensional array detector 27 by 90 ° or more with respect to the center of the fan beam. is there.

 FIG. 13 is a configuration diagram showing a scanning mechanism of the one-dimensional detector type inspection apparatus according to one embodiment of the present invention. In addition to the method shown in Fig. 12, this can also be achieved by operating the target and fan beam collimator 142 in the same way. However, in this case, the electron beam must be made to collide with the target at substantially the same angle at approximately the same angle by bending the traveling direction of the electron beam of the accelerator before the target. In other words, for example, it can be realized by attaching a magnetic field generator 161 that bends an electron beam and a universal joint 162 before the target.

 FIG. 14 is an explanatory view showing an alignment method in the one-dimensional detector type inspection apparatus according to one embodiment of the present invention.

 This section describes the alignment procedure for this device. For example, at first, the direction of the fan is set vertically by the rotating mechanism on the side of the collimator 14 (not shown), and the array direction of the one-dimensional array detector is set horizontally by the rotating mechanism 28 on the detector to irradiate radiation. . As a result, the first detection pattern from the one-dimensional array detector is obtained. The position correction amount in the horizontal direction is obtained from this detection pattern. Next, the fan direction is set to be horizontal, and the array direction of the one-dimensional array detector is set to be vertical, and radiation is applied to obtain a detection pattern from the second one-dimensional array detector. The position correction amount in the horizontal direction is obtained from this detection pattern. As described above, the correction amount necessary for the alignment is determined by the two irradiations.

FIG. 15 is a graph showing a one-dimensional detector output of one embodiment of the present invention. is there. This is an output image from a one-dimensional detector in the case of a fan beam collimator. The three peaks correspond to the measurement of the irradiation direction of the fan beam in the three directions of the center and two places on both sides. From this result, the position correction amount of the alignment, for example, ΔΧ and ΔΥ are determined. Although not shown, the position is corrected by the attitude control means of one or both of the radiation generator and the radiation detector. After correction, measurement may be performed again to confirm that the position correction has been performed normally.

FIG. 16 is an explanatory diagram showing a method for correcting the influence of a test object on a two-dimensional detector output according to one embodiment of the present invention. As in Fig. 15, the three peaks correspond to the measurements in three directions: the center and two places on both sides. As in the case of using a two-dimensional array detector and a pinhole collimator, in general, an ideal pattern cannot always be obtained due to the influence of the inside of the subject in the detector output pattern. For example, if there is an internal structure such as steel frame near the center of the fan beam, ideally a symmetrical chevron pattern will be obtained, and one side will be distorted _; On the other hand, the radiation intensity decreases due to the internal steel frame, and it is impossible to predict in advance unless the internal shape is accurately grasped. However, for example, by measuring the source intensity to a known different intensity, acquiring two or more detector output patterns, and compensating for the effect of the test object, for example, by displaying the logarithmic difference between the two. be able to.

It should be noted that the optical fiber can be used as a means for transmitting a two-dimensional image. By using a large number of fibers and maintaining the relative positional relationship between the optical fibers, the light emission pattern at the entrance can be directly transmitted to the exit. Therefore, a planar scintillator or many scintillators The light emission image of the radiation detecting unit in which the chillers are two-dimensionally arranged can be connected to an image sensor such as a two-dimensional CCD camera by using a large number of optical fibers. Industrial applicability

 ADVANTAGE OF THE INVENTION According to the 1st characteristic of this invention, it is effective in reducing the weight of a radiation detection apparatus, and can enhance the mobility of a radiation inspection apparatus. Furthermore, by using an organic multi-layer type optical amplifying element, a thin film forming technique such as evaporation can be used, and the cost can be reduced by processing a large number of scintillators at once. According to the second feature of the present invention, simple alignment means can be obtained even when the radiation generator and the radiation inspection apparatus are separated by an adjusting collimator such as a pinhole collimator. Unnecessary irradiation can be prevented by using a pinhole or a slit for the adjustment collimator.

 According to the third aspect of the present invention, in addition to the effect of the above-mentioned second aspect, by taking an image while rotating the one-dimensional array detector, it is possible to adapt to the shape of the inspection object or the situation of the imaging place By selecting the scanning direction, the best transmitted image can be obtained.

 According to the fourth feature of the present invention, the radiation generator and the radiation inspection apparatus are separated by rotating the fan beam collimator and acquiring the data while keeping the angle substantially perpendicular to the array direction of the one-dimensional array detector. Even simpler means of alignment can be obtained. In addition, the fan beam collimator can prevent unnecessary irradiation. In addition, high quality transmission images can be obtained by selecting the scanning direction according to the shape of the inspection object or the situation of the imaging location by taking an image while rotating the one-dimensional array detector. .

According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect, the center axis of the radiation generated from the target and the center of the fan beam collimator are obtained. By moving the irradiation field of the fan beam collimator synchronously with the scanning of the one-dimensional array detector with the axes substantially aligned, resolution degradation due to weak radiation intensity at the periphery is prevented. it can.

 As described above, in a radiation inspection apparatus including a radiation generation apparatus and a radiation detection apparatus disposed at a position facing each other with an inspection object interposed therebetween, when the radiation detection apparatus is configured by a two-dimensional array detector, the array detection is performed. An optical amplification element is provided on the surface of the vessel facing the radiation incidence surface. The collimator is switched between alignment work and shooting. When the radiation detector is composed of a one-dimensional array detector, the collimator and the detector can be rotated independently. In a two-dimensional array detector type radiographic inspection system, inspection efficiency is improved. In addition, the same equipment can inspect structures of various dimensions. With a one-dimensional array detector-type radiation inspection system, structures of various dimensions can be inspected with the same device. In addition, since the scanning direction can be selected according to the structure, a high-quality transmission image can be obtained. In addition, reduce unnecessary radiation exposure.

Claims

The scope of the claims  1. A radiation inspection apparatus having a radiation generation apparatus and a radiation detection apparatus arranged at a position facing each other across an inspection object, wherein the radiation detection apparatus includes a two-dimensional array detector, and radiation incidence of the array detector is performed. A radiation inspection apparatus comprising an optical amplification element on a surface facing the surface.  2. In a radiation inspection apparatus having a radiation generation apparatus and a radiation detection apparatus using a two-dimensional array detector arranged at a position facing each other across an inspection object, at least one radiation exit is provided at a radiation outlet of the radiation generation apparatus. A radiation inspection apparatus comprising: an adjustment collimator having a pinhole or a slit; and an imaging collimator that performs irradiation corresponding to an effective range of the two-dimensional array detector.  3. A radiation inspection apparatus having a radiation generation apparatus having a cone beam collimator at a radiation exit, and a radiation detection apparatus using a one-dimensional array detector arranged at a position facing the inspection object, wherein the radiation generation apparatus Switching between an adjustment collimator having one or more pinholes or slits at a radiation exit and an imaging collimator that performs irradiation corresponding to an effective range including scanning of the one-dimensional array detector; A radiation inspection apparatus characterized in that the array detectors independently rotate by 90 ° or more around the central axis of the cone beam. 4. Using a radiation generator equipped with a fan beam collimator at the radiation exit and a one-dimensional array detector arranged at a position facing the inspection object, scan in the direction perpendicular to the array direction of the array detector In the radiation inspection apparatus comprising a radiation detection apparatus having a function of performing the following functions, the fan beam collimator and the one-dimensional array detector independently rotate by 90 ° or more around the center axis of the fan beam. And the fan beam collimator is one-dimensional A radiation inspection apparatus characterized in that a radiation field of a fan beam is moved in synchronization with scanning of an array detector.  5. Using a radiation generator equipped with a fan beam collimator at the radiation exit and a one-dimensional array detector arranged at a position facing the inspection object, scan in the direction perpendicular to the array direction of the array detector The fan beam collimator and the one-dimensional array detector are each independently rotated by 90 ° or more about the center axis of the fan beam. The radiation inspection apparatus is characterized in that the radiation generation apparatus is translated or rotated in order to move the irradiation field of the fan beam in synchronization with the scanning of the one-dimensional array detector. 6. In a radiation inspection apparatus having a radiation generation device and a radiation detection device, the radiation detection device includes a two-dimensional array detector, and is provided on a side of the two-dimensional array detector opposite to a radiation incident side. A radiation inspection apparatus comprising an optical amplification element.  7. A radiation inspection apparatus having a radiation generation apparatus and a radiation detection apparatus, wherein a radiation collimator for adjustment and a collimator for imaging are provided at a radiation exit of the radiation generation apparatus. 8. A radiation generating device and a radiation detecting device, wherein a switching device for switching between an adjusting collimator and an imaging collimator is provided at a radiation outlet of the radiation generating device, and the radiation detector rotates around a central axis of the radiation. A radiation inspection apparatus characterized by having a structure that can be used.