JP2003121392A - Radiation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and highly accurately detect a location at which radiation is scattered backward. SOLUTION: In a transmission-side unit 110 of an X-ray detector 50, a first mask 104 is arranged above an X-ray radiating part 62 of a micro-focus-type X-ray generator 60. A drive motor 108 rotates the first mask 104 to sequentially make each hole row 110 of the first mask 104 correspond to a slit 114 of a first slit plate 112 based on the Hadamard matrix. A reception-side unit 200 comprises a second mask 204 provided with hole rows 210 based on the Hadamard matrix. A drive motor 208 rotates the second mask 204 to sequentially make each hole row 210 correspond to a slit 214 of a second slit plate 212. Backward scattering X-rays 54 incident via the hole rows 210 are passed through a pinhole of a pinhole plate 222 to be incident onto an X-ray detecting part 220, and the X-ray detecting part 220 outputs a detection signal as a current pulse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detector, and more particularly to a radiation detector suitable for detecting weak radiation such as backscattered X-rays.

[0002]

2. Description of the Related Art X-rays have a high substance permeability,
It is widely used for radiographs in the medical field, and for non-destructive inspection devices in the industrial field. The conventional general method of using X-rays is to irradiate the inspection target with X-rays and detect the X-rays that have passed through the inspection target on the opposite side of the inspection target. That is, as shown in FIG. 7, the X-ray generator 12 is arranged on one side of the inspection object 10 and the X-ray film or CCD for detecting the X-rays 14 on the other side of the inspection object 10.
An X-ray receiver 16 such as a camera is arranged, and the X-ray 14 transmitted through the inspection object 10 is received by the X-ray receiver 16.
The image is detected (detected) and inspected for the presence or absence of the internal defect 18 of the inspection object 10.

A technique called computer tomography (CT) is used to obtain a three-dimensional image of the inspection object 10. In this CT, as shown in FIG. 8, an X-ray generator 12 is arranged on one side of the inspection object 10 and an X-ray receiver 20 such as a CCD camera or a scintillation detector is provided on the other side of the inspection object 10. Deploy. Then, the X-ray generator 12 is rotated around the inspection object 10 or the arrow 2
As shown in FIG. 6, the X-ray receiver 20 is moved along the inspection target 10 to radiate the X-rays 14 at a plurality of positions, and the X-ray receiver 20 is rotated around the inspection target 10 or along the inspection target 10 as indicated by an arrow 24. The tomographic image (cross-sectional image) of the inspection target 10 is obtained by processing the received signal of the X-ray receiver 20 by a computer and receiving the X-rays 14 at a plurality of positions.

[0004]

As described above, in the conventional so-called X-ray apparatus, the transmitted X-rays are detected, so that the X-ray source X-ray is provided on one side of the inspection object 10.
It is necessary to dispose the line generator 12 and dispose the X-ray receivers 16 and 20 which are X-ray detectors on the other side of the inspection object 10.
Therefore, when the inspection object 10 is thick, there is a problem that the X-ray 14 is attenuated and cannot be transmitted through the inspection object 10. Further, when the inspection target 10 is a huge structure such as an aircraft, it is difficult to align the X-ray generator 12 and the X-ray receiver 16 with each other. Moreover, since the inspection is performed by using the transmitted X-rays, it is difficult to detect defects such as cracks generated in the wing of the aircraft or the surface layer of the airframe.

Therefore, the development of a device for detecting backscattering of X-rays and visualizing it is under study. However, since X-rays have a large substance penetrating ability, the amount of backscattering is extremely small. For this reason, it is difficult to detect extremely weak backscattered X-rays while leaving information on the angle of arrival of the backscattered X-rays, and obtaining an image based on the backscattered X-rays has not been realized yet. Is the current situation.

When detecting backscattered X-rays while obtaining information on the angle of arrival, it is conceivable to use a pinhole type X-ray detector. This pinhole type X
When the backscattered X-rays are detected by using the X-ray detection apparatus and the internal structure of the inspection object is to be known, it is necessary to move the pinhole X-ray detection apparatus to detect the backscattered X-rays at many points. . For this reason, not only a lot of time is required, but also the backscattered X-rays are extremely weak, so that they are greatly affected by disturbance and it is difficult to clearly perceive the internal structure.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to make it possible to easily detect the backscattered position of radiation with high accuracy. Another object of the present invention is to shorten the measurement time.

[0008]

In order to achieve the above object, the present invention provides a first plurality of holes arranged in front of a radiation source according to a modulation mode of a quadrature modulation pattern for transmitting radiation. A first mask; and a first slit plate that is provided so as to be movable relative to the first mask and has a slit that exposes one of the hole rows formed in the first mask;
Of the radiation emitted from the radiation source, a radiation detection unit on which radiation backscattered by the inspection target is incident,
A second mask, which is arranged in front of the radiation detection unit and has a plurality of hole rows according to the modulation mode of the orthogonal modulation pattern for transmitting backscattered radiation, and is provided so as to be movable relative to the second mask. A second slit plate capable of shielding the radiation and having a slit exposing one of the hole rows formed in the second mask;
An incident direction specifying plate that has a radiation passage portion that is interposed between a mask and the radiation detection portion, and that determines the incident direction of the radiation that has entered the radiation detection portion in cooperation with the second mask,
It is characterized by having. The first mask, the first slit plate, the second mask, and the second slit plate are preferably formed in a disc shape.

[0009]

The present invention, which has been made as described above, emits radiation from a radiation source according to a modulation mode of a quadrature modulation pattern.
Then, the radiation detection section also detects (receives) the radiation backscattered by the inspection object according to the modulation mode of the orthogonal modulation pattern. Since the radiation detection unit is configured to detect the radiation that has entered through the incident direction identification plate, the position of the radiation passage unit of the incident direction identification plate and the hole array of the second mask are configured. The direction of the backscattered radiation can be known from the position of the hole. Therefore, if the radiation direction of the radiation from the radiation source is known, the position where the radiation is backscattered can be easily and accurately known. Moreover, since radiation is emitted and detected through a row of holes forming a modulation mode composed of a plurality of holes, pinhole radiation detectors are arranged and detected at a plurality of points at once. Not only can the same effect be obtained and the detection time can be shortened, but also the detection accuracy can be improved and a clear image (video) can be obtained by the weak backscattered radiation.

When the first mask, the first slit plate, the second mask, and the second slit plate are formed in a disc shape, a plurality of hole rows can be easily switched based on the modulation mode of the orthogonal modulation pattern simply by rotating the mask. Radiation can be emitted and detected, and the device can be made compact.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the radiation detecting apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view in which a part of a radiation detecting apparatus according to an exemplary embodiment of the present invention is cut away, and shows an example configured to detect X-ray backscattering. In FIG. 1, an X-ray detection device 50 which is a radiation detection device is
Transmitting unit 100 emitting line 52 and backscattering X
It comprises a receiving unit 200 for detecting the line 54.

In the transmitting side unit 100, a part of the side portion of the cylindrical casing 102 is cut out so that the X-ray emitting portion 62 of the X-ray generator 60 can be inserted into the casing 102. In the embodiment, the X-ray generator 60 is a microfocus type X-ray generator, and
A focus size of less than μm can be obtained. A fan-shaped radiation guide 64 arranged in the radial direction of the casing 102 is attached to the X-ray radiation unit 62,
The X-ray beam on the fan is radiated upward in the figure.

The transmitter unit 100 includes an X-ray emitting section 62.
A disk-shaped first mask 104 is arranged on the front side of the casing, that is, on the upper part of the casing 102. This first mask 10
The central portion 4 is attached to a rotating shaft of a motor 108, which serves as a driving unit, whose central portion is fixed to the bottom plate 106 of the casing 102, and is rotatable. Then, the first mask 10
4 has a plurality of hole rows 110. As will be described in detail later, these hole rows 110 are formed according to a modulation mode based on a Hadamard matrix that is an orthogonal modulation pattern, and are arranged radially at equal intervals with respect to the center of the first mask 104. The holes that make up the hole array 110 are
The first mask 104 penetrates in the thickness direction, and the X-ray 52 can be radiated to the outside through this hole.

On the first mask 104, the first mask 1
The first slit plate 112 is arranged in close proximity to 04 or in contact with the first mask 104. The first slit plate 112 is fixed to the upper end of the casing 102. Therefore, the first mask 104 and the first slit plate 11
2 is capable of relative rotation (relative movement). Then, the first slit plate 112 is made of a metal or the like so that the X-ray 52
Is formed to have a thickness capable of shielding the light, and has one slit 114 in the radial direction. This slit 114 is
The width and length are such that any row 110 of holes formed in the first mask 104 can be exposed, and it is located above the radiation guide 64 of the X-ray generator 60. Therefore, the X-rays 52 emitted from the X-ray emitting unit 62 of the X-ray generator 60 are exposed to the outside only from the hole array 110 of the first mask 104 at the position corresponding to the slit 114 provided in the first slit plate 112. It is emitted and irradiates the inspection object 10 as shown in FIG.

The Hadamard matrix for forming the quadrature modulation pattern is a symmetric matrix in which the elements are composed of "+1" and "-1", and the elements at symmetrical positions along the diagonal line are the same. . The Hadamard matrix H is defined by the following recurrence formula (1).

[Equation 1] However, in Formula 1, k is an order.

That is, for example, a third-order Hadamard matrix H
⁽³⁾ is represented as shown in FIG. Therefore, when each hole array 110 provided in the first mask 104 of the transmission side unit 100 is based on the cubic Hadamard matrix, the formation pattern of the holes forming the hole array 110 is as shown in FIG. become. In FIG. 3 (2), the white squares correspond to “1” of the Hadamard matrix, and holes are made to indicate that X-rays 52 can be emitted. The shaded squares indicate the Hadamard matrix. It corresponds to “−1” of No., and no holes are made, indicating that the X-ray 52 cannot be emitted.
Then, the radiation of the X-rays 52 from each hole array 110 causes the first mask 104 to rotate in the state where the first mask 104 and the first slit plate 112 are overlapped, as indicated by an arrow 120 in FIG. The hole array 110 is formed by the slits 1 of the first slit plate 112.
By exposing from 14.

The receiving side unit 200 is arranged on the same side as the transmitting side unit 100 with respect to the inspection object 10 at an appropriate interval with respect to the transmitting side unit 100. Then, in the reception side unit 200, as in the transmission side unit 100, the second mask 204 is rotatably arranged on the upper part of the cylindrical casing 202. This second mask 20
4 has a drive motor 208 whose center is fixed to the bottom plate 206 of the casing 202, and
It is rotatable with respect to 02. In the case of the embodiment, the drive motors 108 and 208 use stepping motors, but may be servo motors or may be mechanisms that intermittently move using cylinders or ratchets. Good.

The second mask 204 has a transmitting unit 1
Similar to the first mask 104 of No. 00, a plurality of hole arrays 210 according to the modulation mode based on the Hadamard matrix are formed radially at equal intervals with respect to the center of the second mask 204. Then, on the second mask 204, the casing 2
A second slit plate 212 fixed to No. 02 is arranged.
The second slit plate 212 is formed of metal or the like with a thickness that can shield the backscattered X-rays 54. In addition, the second slit plate 212 has one slit 21 in the radial direction.
Have four. This slit 214 is used for the second mask 2
The size is such that an arbitrary hole row of the plurality of hole rows 210 provided in 04 can be exposed. Therefore, the back-scattered X-rays 54 from the inspection object 10 are the slits 2 of the second slit plate 212 of the hole array 210 provided in the second mask 204.
Only the row 210 of holes located at the position corresponding to 14 enters the casing 202.

The casing 202 of the receiving unit 200
An X-ray detection unit 220 is provided inside. The X-ray detector 220 is located below the slit 214 provided in the second slit plate 212 and is fixed to the bottom plate 206 of the casing 202. Further, a pinhole plate 222, which is an incident direction specifying plate, is arranged between the X-ray detection unit 220 and the second mask 204. This pinhole plate 22
2 is arranged at an appropriate distance from the second mask 204, has a pinhole 223 which is a radiation passage section whose operation will be described later, and has an X-ray detection section 220, as shown in FIG.
It is located close to. Then, the X-ray detection unit 220
As shown in FIG. 5, is a scintillator 224 provided to face the lower surface of the pinhole plate 222 for converting the backscattered X-rays 54 into light, and the light emitted from the scintillator 224 is converted into electrons. Photomultiplier tube 2 to multiply the number of electrons
26 and.

The X-ray detection device 50 having the above structure
As shown in FIG. 2, the transmission side unit 100 and the reception side unit 200 are arranged on the same side with respect to the inspection target 10. The drive motor 108 of the transmission side unit 100 and the drive motor 208 of the reception side unit 200 are connected to the motor drive controller 70, and the rotation is controlled by the motor drive controller 70. The motor drive controller 70 is connected to a computer 72 that serves as an image generation device, and drive motors 108 and 208 are connected.
The drive signal given to the computer is input to the computer 72.

On the other hand, the X-ray generator 60 includes an X-ray controller 7
4 and the output and the like can be controlled by the X-ray controller 74. Then, the photomultiplier tube 22 of the X-ray detection unit 220 provided in the reception side unit 200
Reference numeral 6 is connected to a current / voltage converter 76, and a detection signal output as a current pulse is converted into a voltage pulse by the current / voltage converter 76. This current / voltage converter 7
The voltage pulse output by 6 is input to the computer 72 after being amplified by the amplifier 78.

The detection of the backscattered X-rays 54 by the X-ray detection device 50 of the embodiment and the visualization by the backscattered X-rays 54 are performed as follows. First, as shown in FIG.
And the transmission side unit 200 are arranged at the same initial position of the inspection target 10, and the respective slit plates 112 and 212 are made to face the inspection target 10. In the case of the embodiment, the transmission side unit 100 and the reception side unit 200 are installed on a movable carriage or the like so that they can be moved integrally. Then, as shown in step 300 of FIG. 4, when the X-ray generator 60 is turned on via the X controller 74 and an inspection start command is input to the computer 72, the computer 72 causes the motor controller 70 to operate. Give a drive command to.

The motor controller 70 drives the drive motor (stepping motor) of the transmission side unit 100 to rotate the first mask 104 in accordance with a control program given in advance, and as shown in step 301 of FIG. 4, A predetermined first hole array 110 of the first mask 104, for example, the hole array 110 composed of the top hole pattern of FIG.
12 corresponding to the slit 114, and the slit 11
The number information (hole pattern information) of the hole row corresponding to No. 4 is sent to the computer 72. In addition, the motor controller 70 is a drive motor (stepping motor) for the receiving unit 200.
The second mask 204 is rotated by driving 208, and a predetermined first hole array 210 is formed in the slit 21 of the second slit plate 212.
4 is moved to a position corresponding to 4 (step 302), and the number information (hole pattern information) of this hole array 210 is transferred to the computer 7.
Enter 2. Thereby, the X-ray 52 is radiated from each hole of the hole array 110 corresponding to the slit 114 of the transmission side unit 100, and the backscattered X-ray 54 by the inspection object 10 of the X-ray 52 is the slit 214 of the reception side unit 200.
Is detected through each hole of the hole array 210 corresponding to. The processing from step 300 to step 302 can be performed in any order.

The backscattered X-rays 54 of the X-rays 52 radiated to the inspection object 10 are passed through the slits 214 of the second slit plate 212 of the receiving unit 200 and the hole array 210 of the second mask 204 in the casing 202. And is detected by the X-ray detection unit. That is, the casing 202
As shown in FIG. 5, a part of the backscattered X-rays 54 entering the inside enters the scintillator 224 of the X-ray detector 220 via the pinhole 223 of the pinhole plate 222 and is converted into light. It The light emitted from the scintillator 224 enters the photomultiplier tube 226. Photomultiplier tube 22
6 converts the light from the scintillator 224 into electrons on the photoelectric conversion surface, further multiplies the electrons, and outputs them as current pulses.

This current pulse is converted into a current / voltage converter 76.
After being converted into a voltage pulse by the amplifier, it is amplified by the amplifier 78 and input to the computer 72. The computer 72 sends the voltage pulse (received signal) input from the amplifier 78 to the first mask 1 sent by the motor controller 70.
The number of the hole row 110 of No. 04 and the hole row 2 of the second mask 204
It is stored in association with the combination with the number of 10 (step 303).

When the motor controller 70 controls the rotation of the second mask 204 and a predetermined time elapses, as shown in step 304, the hole array 2 of the second mask 204.
All of the 10 slits 214 of the second slit plate 212
It is determined whether it has been moved to a position corresponding to. When all the hole rows 210 are not moved to the positions corresponding to the slits 214, the drive motor 208 is driven to move to the next hole row 2
10 to the position corresponding to the slit 214 (step 3
05), the number information of the hole row 210 is calculated by the computer 72
To enter. Then, in the same manner as described above, the backscattered X-ray 5
4 is detected, and the computer 72 stores the received signal (step 303). The processing of steps 303 to 305 is performed for all the hole rows 2 of the second mask 204.
It is repeated until the detection of the backscattered X-rays 54 by 10 is completed.

When the motor controller 70 determines in step 304 that all the hole arrays 210 of the second mask 204 have been moved to the positions corresponding to the slits 214 of the second slit plate 212, the process further proceeds to step 306. It is determined whether or not all the hole arrays 110 of the one mask 104 have been moved to positions corresponding to the slits 114 of the first slit plate 112. All holes 11 in the first mask 104
0 is not moved to the position corresponding to the slit 114, the drive motor 1 of the transmission side unit 100 is determined.
08 is driven to move the next hole array 110 to a position corresponding to the slit 114 (step 307), and the process returns to step 302. Then, the motor controller 70 drives the drive motor 208 of the reception-side unit 200 to move the first hole array 210 of the second mask 204 to a position corresponding to the slit 214 of the second slit plate 212. The motor controller 70 inputs the number information of the hole array 110 of the first mask 104 and the hole array 210 of the second mask 204 to the computer 72.

Hereinafter, in the processing from step 302 to step 307, all the hole rows 110 of the first mask 104 are moved to the positions corresponding to the slits 114 of the first slit plate 112, and are emitted from the last hole row 110. X-ray 52
Is repeated until the detection of the backscattered X-rays 54 through all the hole rows 210 of the second mask 204 is finished. Thus, assuming that the number of hole rows 110 of the first mask 104 is N and the number of hole rows 210 of the second mask 204 is N, N × N sets of Hadamard mask sets are obtained.

When all combinations of the hole array 110 of the first mask 104 and the hole array 210 of the second mask 204 are completed, the motor control unit 70 inputs the fact to the computer 72 in step 306. Computer 72
Performs Hadamard inverse transformation of the stored reception data (detection data) as shown in step 308, and the first mask 10
No. 21 of the first mask 204 in which the backscattered X-rays 54 are incident on the pin holes 223 of the pinhole plate 222.
The positions of the holes forming 0 and the backscattered X-rays 54
Image is generated and output to an output device such as a display device (step 309).

That is, by performing the Hadamard inverse transformation, as shown in FIG. 5, the inspection object 10 is irradiated with the X-ray 52 emitted from the minute focus F of the X-ray generator 60.
The position of the holes A forming the hole array 110 provided in the first mask 104 of the transmission side unit 100 and the reception side unit 2
It is possible to specify the positions of the holes B that form the hole array 210 formed in the second mask 204 when the backscattered X-rays 54 are incident on the pinhole 223 provided on the pinhole plate 222 of No. 00. . Therefore, the position where the backscattering of the inspection target 10 occurs is a straight extension line L connecting the focal point F of the transmission side unit 100 and the hole A through which the X-ray 52 has passed.
₁ and a straight line L connecting the pinhole 223 of the receiving unit 200 and the hole B through which the backscattered X-ray 54 has passed
It can be obtained as the intersection P with ₂ . That is, the backscattered X-rays 54 can be easily detected, the arrival direction of the backscattered X-rays 54 can be easily known, and a cross-sectional image (two-dimensional image) of the inspection object 10 can be obtained.
If the inspection object 10 is not uniform and there are internal defects 18 such as cavities and foreign particles, the probability of backscattering at that portion is different from the probability of backscattering of the inspection object 10 itself, so an image of the internal defect 18 ( Video) can be obtained.

When the computer 72 obtains a three-dimensional image of the inspection object 10, the backscattered X-rays 5 for all of the inspection area are shown in step 310 of FIG.
It is determined whether the detection (inspection) of 4 has been performed. When the inspection is not performed on all the inspection areas, the X-ray detection apparatus 50 is moved (traversed) by a predetermined amount as shown in step 311. After that, the first step 301
Then, the processing of steps 301 to 311 described above is repeated.

As described above, in the embodiment, the X-ray 52 emitted from the micro focus F is passed through the hole array 110 having the hole pattern based on the Hadamard matrix to be inspected 1
0, and the backscattered X-rays 54 are used for the hole array 210 and the pinhole 2 having a hole pattern based on the Hadamard matrix.
The position where the backscattering of the X-ray is generated can be easily and accurately determined because the signal is received via the signal. In addition, the hole rows 110, 21 composed of a large number of holes
Since X-rays are radiated and detected via 0, if the number of hole arrays 110 and 210 is N, the number is N compared with the case of using a pinhole type X-ray detector. ^2/4 times more efficient is improved, thereby improving the detection accuracy.

The above embodiment is an explanation of one aspect of the present invention. For example, in the above embodiment,
When obtaining a three-dimensional image of the inspection object 10, an image (image) every time the detection of backscattered X-rays ends at each inspection position.
Although the case of generating and displaying is described, the image may be generated after the X-ray detection is completed for all the inspection areas. Further, in the above-described embodiment, the slit plates 112 and 212 are connected to the masks 104 and 20.
The case where the mask 10 is arranged above
4, 204 may be placed below. In the above embodiment, the case where the masks 104 and 204 are rotated has been described, but they may be moved linearly. Further, in the above embodiment, the case where the radiation is X-rays has been described, but the radiation may be comma rays or particle rays.

Further, in the above embodiment, the case where the incident direction specifying plate is the pinhole plate 222 has been described, but it may be a slit plate as shown in FIG. That is, this incident direction specific slit plate 230 is
The backscattered X-rays 54 are arranged on the front surface of the X-ray detection unit 220.
Is provided with a passage slit 232. This passage slit 232 is, as shown in FIG.
It is arranged so as to be orthogonal to the hole array 210 formed in the second mask 204 rotating like 34. As described above, by using the passing slit 232 instead of the pinhole 223, the first mask 10 on the transmission side unit 100 side is formed.
4 does not have to be on the same plane as the surface of the second mask 204 of the reception-side unit 200, which facilitates the assembly of the X-ray detection apparatus.

[0035]

As described above, according to the present invention, the radiation from the radiation source is radiated (transmitted) through the first mask according to the modulation mode of the orthogonal modulation pattern, and the radiation detection unit side At the second backscattered radiation by the inspection object according to the modulation mode of the quadrature modulation pattern.
Since the detection is performed via the mask and the incident direction specifying plate, the arrival direction of the radiation can be easily and accurately known. Therefore, if the radiation direction of the radiation from the radiation source is known, the position where the radiation is backscattered can be easily and accurately known. Moreover, since radiation is emitted and detected through a row of holes forming a modulation mode composed of a plurality of holes, pinhole radiation detectors are arranged and detected at a plurality of points at once. Not only can similar effects be obtained and detection time can be shortened, but
It is possible to improve the detection accuracy and obtain a clear image (video) due to the weak backscattered radiation.

When the first mask, the first slit plate, the second mask and the second slit plate are formed in a disc shape, a plurality of hole rows can be easily switched based on the modulation mode of the orthogonal modulation pattern simply by rotating the mask. Radiation can be emitted and detected, and the device can be made compact.

[Brief description of drawings]

FIG. 1 is a perspective view in which a part of a radiation detection apparatus according to an exemplary embodiment of the present invention is cut away.

FIG. 2 is an explanatory diagram of a schematic configuration of an imaging device using the radiation detection device according to the exemplary embodiment.

FIG. 3 is an explanatory diagram of a hole pattern forming a hole row formed in the first mask according to the embodiment.

FIG. 4 is a flowchart illustrating an operation of the video device according to the embodiment.

FIG. 5 is a schematic diagram illustrating how to determine the arrival direction of backscattered radiation by the radiation detection apparatus according to the exemplary embodiment.

6A and 6B are explanatory views of an incident direction specifying plate according to another embodiment, in which FIG. 6A is a perspective view, and FIG. 6B is a view showing a relationship between a passing slit of the incident direction specifying plate and a hole array of a second mask. It is a figure explaining.

FIG. 7 is a diagram illustrating an example of a conventional general X-ray detection method.

FIG. 8 is a schematic diagram illustrating a conventional computer tomography method using X-rays.

[Explanation of symbols]

10 ………… Inspection target, 18 ………… Internal defect, 50 …………
Radiation detector (X-ray detector), 52 ... X-ray, 54
……… Backscattered X-rays, 60 ……… X-ray generators, 100…
...... Sending unit, 104 ………… First mask, 10
8, 208 ......... Drive motor, 110, 210 ......... Hole row, 112 ......... First slit plate, 114, 214 ...
… Slit, 200 ………… Receiver unit, 204 ……
… Second mask, 212 ……… Second slit plate, 220…
...... X-ray detector 222, 230 ………… Incident direction specific plate (pinhole plate, incident direction specific slit plate) 223,
232 ......... Radiation passage part (pinhole, passage slit).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) G01T 7/00 G01T 7/00 B G21K 1/02 G21K 1/02 G 1/04 1/04 S 5 / 02 5/02 XF Term (reference) 2G001 AA01 AA10 BA15 CA01 DA01 DA03 FA06 HA13 JA01 JA06 KA03 LA02 SA01 SA04 2G088 EE29 EE30 FF02 FF14 GG18 JJ01 JJ09 JJ12 JJ22 KK32 KK33 KK35 LL09 4C093 CA13 A5022

Claims (2)

[Claims] 1. A first mask, which is arranged in front of a radiation source and has a plurality of hole rows according to a modulation mode of a quadrature modulation pattern which transmits radiation, and a first mask which is provided so as to be movable relative to the first mask. The first
A first slit plate having a slit that exposes one of the hole rows formed in the mask, a radiation detection unit on which radiation backscattered by an inspection target of the radiation emitted from the radiation source is incident, and this radiation A second mask, which is arranged in front of the detection unit and has a plurality of hole rows according to the modulation mode of the orthogonal modulation pattern for transmitting backscattered radiation, and the second mask provided so as to be movable relative to the second mask. And a second slit plate having a slit that exposes one of the hole rows formed in the second mask, and a radiation passage section interposed between the second mask and the radiation detection section. And an incident-direction specifying plate that determines an incident direction of the radiation that has entered the radiation detection unit in cooperation with the second mask. 2. The radiation detection device according to claim 1, wherein the first mask, the first slit plate, the second mask and the second slit plate are each formed in a disk shape. apparatus.