JP2021188951A - Imaging device and imaging method - Google Patents

Abstract

To reduce the size of a device that includes a neutron source and a detector to be smaller than conventional ones and carry out imaging with which neutrons are utilized.SOLUTION: An imaging device comprises: a neutron source for generating neutrons; a moderator including at least a portion of a path leading from the neutron source to an object irradiated with the neutrons and reducing the energy of the neutrons; a diaphragm member formed with an absorber that absorbs the neutrons and having a hole which the neutrons having been moderated by the moderator and having passed through the object or the neutrons scattered in the object can pass through; and a detector for detecting the neutrons having passed through the hole of the diaphragm member.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image pickup device and an image pickup method using neutrons.

Neutrons are expected to be used as a new inspection method to replace X-rays. FIG. 1 illustrates a problem when neutrons are used for inspection or imaging. Neutrons generated from neutron sources are fast neutrons. As illustrated in the upper part of FIG. 1, fast neutrons also pass through the detector, so that they are not detected by the detector and cannot be used as radiation for detection as they are. Therefore, as shown in the lower part of FIG. 1, when neutrons from a neutron source are used for inspection or imaging, fast neutrons are decelerated and used via a moderator.

FIG. 2 shows an inspection device or an imaging device using a conventional proton beam accelerator. Conventional equipment generally consists of a proton beam accelerator, a target station, a neutron conduit, an object to be inspected (imaging), and a detector. In this configuration, protons accelerated by a proton accelerator collide with a neutron target in the target station to generate neutrons. The generated neutrons are guided to the object by the neutron conduit, and the neutrons that have passed through the object are detected by the detector. FIG. 3 illustrates the configuration of an inspection device or an image pickup device using neutrons from a neutron source using an electron accelerator. The configuration of FIG. 3 is similar to that of the proton accelerator, although there is a difference in using electrons as the neutron source.

Further, in recent years, a small neutron generator has been developed, and packaging as an inspection device or an image pickup device is desired. However, even when a small neutron generator is used, the neutrons generated from the neutron generator are fast neutrons, and the neutrons are decelerated via the moderator and used. At this time, the neutrons are beamed through a hole called a collimator, which has a sufficiently small diameter for the distance to the place where the neutrons are measured, so that the neutron extraction efficiency is poor, neutron loss occurs, and the image quality is improved. Can't improve. Further, since it is necessary to secure a sufficient distance from the collimator to the measurement position in order to obtain a wide irradiation field, a large detector is required for inspection of a large sample. However, existing detectors can only handle up to a certain size (for example, 30 cm in length and width).

Masayoshi Tamaki, Series Lecture Basics and Applications of Neutron Imaging Technology (Basics, Part 3) Principles of Neutron Imaging Technology, Japan Radioisotope Association, RADIOISOTOPES, 2007, Vol. 56, p.329-p.337 Yoshie Otake and 2 others, "Perspective of damage in concrete caused by neutrons-Protecting the safety of infrastructure users by non-destructive inspection method-", [online], RIKEN, [Search on April 17, 2nd year of Reiwa], Internet, <URL: https: // www. riken. jp / press / 2016/201610101_2 /> Kai Masuda, Introductory Lecture "How to Make Neutrons" (3) Fusion Neutron Source, Journal of the Japanese Society of Neutron Science "Ripples" 2017, Vol.27, No.3, p.113-p.116 Shigeki Seko et al., Research on detection of concrete cavities and water retention inside steel sheets by RI neutron beam measuring device, Japan Concrete Engineering Society, Annual Proceedings of Concrete Engineering, 2019, Vo.141, No.l, p. 1763-p.1768

An object of the present invention is to provide an imaging technique using neutrons by making a device including a neutron source and a detector smaller than before. Further, the present invention also provides an inspection method that enables inspection of a large sample even with a small detection device.

One aspect of the technique disclosed in the present invention is exemplified by an image pickup apparatus. The imaging device includes a neutron source that generates neutrons, a moderator that reduces the energy of the neutrons by including at least a part of the path from the neutron source to the object to be irradiated with the neutrons, and the neutrons. A drawing member formed of an absorbent material that absorbs and having a hole through which neutrons decelerated by the moderator and transmitted through the object or neutrons scattered in the object can pass through the drawing member and the hole of the drawing member. It is equipped with a detector that detects neutrons.

According to this imaging device, a device including a neutron source and a detector can be made smaller than before to perform imaging using neutrons.

It is a figure which illustrates the problem when the neutron is used for inspection or imaging. It is a figure which illustrates the structure of the inspection apparatus or the image pickup apparatus which used the neutron from the neutron source by the conventional proton beam accelerator. It is a figure which illustrates the structure of the inspection apparatus or the image pickup apparatus which used the neutron from the neutron source by the electron accelerator. It is a figure which illustrates the structure of the image pickup apparatus which concerns on one Embodiment of this invention. It is a figure which illustrates the structure of a detector. Another example of a detector. It is a figure which illustrates the 1st operation of 1st Embodiment in comparison with a comparative example. It is a figure which illustrates the 2nd operation of 1st Embodiment in comparison with the comparative example. It is a figure which illustrates other features of the image pickup apparatus of 1st Embodiment. It is a figure which illustrates the structure of the image pickup apparatus which concerns on 2nd Embodiment of this invention.

Embodiments of the present invention exemplify an image pickup apparatus and an image pickup method. This imaging device includes a neutron source that generates neutrons, a moderator that reduces the energy of neutrons, and absorbs neutrons, including at least part of the path from this neutron source to the object to be irradiated with neutrons. A throttle member formed of a material and having a hole through which a neutron decelerated by the moderator and transmitted through the object or a neutron scattered in the object can pass, and a neutron passing through the hole of the throttle member are detected. It is equipped with a detector. Here, the neutron generated from the neutron source is a fast neutron. Fast neutrons have high kinetic energy and pass through objects and detectors, so they cannot usually be detected by detectors. Therefore, moderators that reduce the energy of neutrons are used to convert fast neutrons into lower energy thermal neutrons. Thermal neutrons are scattered by an object, a part of which passes through a diaphragm member, and is detected by a detector. The detector is preferably a two-dimensional detector. Therefore, the diaphragm member and the detector form a so-called pinhole camera, and the neutron shading on the two-dimensional detection surface depends on the situation of neutron scattering on the object, and therefore the material and composition of the object. Form an image by. Neutrons are generally scattered by collision with hydrogen atoms and the like, and are easily affected by deceleration and the like. Therefore, when the object contains a large amount of hydrogen atoms, it is possible to form an image that captures the shade. The imaging method according to the embodiment of the present invention can be specified as a method for performing the above processing.

<First Embodiment>

(composition)
FIG. 4 is a diagram illustrating the configuration of the image pickup apparatus 10 according to the embodiment of the present invention. The image pickup apparatus 10 includes a neutron source 1, a neutron reflector 2 that reflects neutrons, a moderator 3, a pinhole collimator 4, and a detector 5. A shielding material 6 is provided around the detector 5 (see FIG. 7).

The neutron source 1 is, for example, a neutron generator manufactured by Sodern of France. The neutron source 1 generates neutrons by, for example, incident a deuterium (D) beam on a metal target in which tritium (T) and deuterium (D) are occluded. A neutron generator tube having an acceleration voltage of deuterium (D) of about several tens of kV to about 100 kV, a length of several tens of centimeters, and a diameter of about 10 cm is on the market (Non-Patent Document 3). However, in the embodiment of the present invention, the neutron source 1 is not limited to these.

The neutron reflector 2 is graphite or the like. As the neutron reflector 2, beryllium, lead, iron, tungsten carbide, and zirconium can also be used. The neutron reflector 2 reflects the neutrons generated by the neutron source 1 and advances in the direction of the moderator 3 and the inspection object. Neutron reflection occurs when neutrons elastically collide with the neutron reflector 2. Therefore, it is desirable that the structure of the neutron reflector 2 surrounds the moderator 3 and the outside of the inspection object as much as possible.

In FIG. 4, the moderator 3 and the neutron reflector 2 are provided on the two surfaces of the hexahedron surrounding the inspection object. However, the neutron reflector 2 may cover one surface or three or more surfaces of such a hexahedron. For example, the entire surface of such a hexahedron may be covered with a neutron reflector 2, and an opening for introducing neutrons from the neutron source 1 may be provided on either surface thereof. Further, the structure of the neutron reflector 2 may cover one or more faces of a polyhedron other than the hexahedron. Further, the structure of the neutron reflector 2 is not limited to the polyhedron, and may have a curved surface. For example, the structure of the neutron reflector 2 may be a structure that covers at least a part of the moderator 3 and the spherical surface, the ellipsoidal surface, the parabolic surface by the rotating parabola, etc. surrounding the inspection object.

The moderator 3 is also called a scatterer and decelerates neutrons from fast neutrons to thermal neutrons by scattering. The moderator 3 contains a large amount of hydrogen and is decelerated by collision between neutrons and hydrogen, and is, for example, water, polyethylene, mesitylene, or the like. The structure of the moderator 3 is not limited. However, as shown in FIG. 4, since the moderator 3 is interposed between the neutron reflector 2 and the inspection object and includes at least a part of the neutron flow path, the neutron reflector 2 and the inspection object are inspected. The space between and is filled. As a result, the structure of the moderator 3 may depend on the inner surface structure of the neutron reflector 2 or the outer surface structure of the inspection object. For example, in the example of FIG. 4, the inspection object installed in the space of the hexahedron is provided in the space inside the neutron reflector 2 covering the two surfaces of the hexahedron, and has the same structure as the neutron reflector 2. Has a structure. However, when the neutron reflector 2 adopts a structure other than that shown in FIG. 4, the moderator 3 may also have a structure that covers the inspection object inside the neutron reflector 2.

The pinhole collimator 4 is provided with pinholes, that is, minute holes in a part of the structure of the absorbent material that absorbs neutrons. That is, the pinhole collimator 4 forms a so-called pinhole camera together with the detector 5, and forms an inverted image of the inspection object on the detection surface of the detector 5. The action of the pinhole collimator 4 in the embodiment of the present invention is different from that of the pinhole camera for detecting light, and the action of the pinhole collimator 4 is to detect neutrons, but the optical action is the same as that of the pinhole of the pinhole camera.

The material of the pinhole collimator 4 is preferably a substance that absorbs neutrons, and preferably lithium (Li), boron (B), cadmium (Cd), gadolinium (Gd), or the like. This is because these substances have a large reaction (absorption) cross section of neutrons. The structure of the pinhole collimator 4 is a plate-shaped member, for example, a disk-shaped member, and a minute hole is formed in the central portion thereof. It is desirable that the plate-shaped member has a structure in which the vicinity of the hole, for example, the portion in contact with the hole is thin in the cross section including the central axis of the hole, and the thickness increases as the distance from the hole increases. As an example, as illustrated in FIG. 4, the cross section of the plate-shaped member is in the shape of two triangles having vertices facing each other with a hole in between. Therefore, the thickness of the plate-shaped member is thin at the hole portion, and a shallow hole is formed. With such a configuration, the neutrons passing through the pores are distributed on the detection surface of the detector 5 while suppressing the generation of shading. On the contrary, for example, when the thickness of the plate-shaped member increases in the vicinity of the hole and a deep hole is formed, the ratio of neutrons traveling straight in the axial direction of the hole is higher than the ratio of neutrons traveling diagonally in the hole. As the number increases, the concentration of neutrons near the central portion on the detection surface of the detector 5 increases from the peripheral portion, and the neutrons detected on the detection surface tend to be uneven in shade and concentration.

The diameter of the hole affects the resolution and sensitivity of the image obtained from the detector 5. However, in the first embodiment, the diameter of the hole is appropriately set to a size that does not excessively reduce the sensitivity in relation to the size of the inspection object. The diameter of the hole is, for example, about 0.2 mm to 10 mm. Further, by changing the size of this hole, it is possible to change the shooting conditions, for example, the resolution of the image and the gain (sensitivity) of the detector 5 at the time of shooting.

The detector 5 includes a planar scintillator that emits light at the incident location when a neutron is incident, and an image acquisition device in which image pickup elements are arranged in a planar manner provided superimposing on the planar scintillator. The dimension of the detector 5 in the plane direction can be appropriately selected in relation to the object to be photographed, and is a rectangle having a side of about 5 cm to 30 cm. As already described, the periphery of the detector 5 is covered with the shielding material 6 in a direction other than the incident direction of the neutrons (see FIG. 7).

FIG. 5 illustrates the configuration of the detector 5. In FIG. 5, the detector 5 amplifies a planar scintillator, an array of image pickup elements (photodiodes) superimposed on the scintillator, and an output signal of the image pickup element, which is an element of each element of the photodiode array, and external terminals. Includes a thin film (TFT) that outputs to. The scintillator is, for example, a scintillator in which LiF and ZnS are held on a substrate with an organic binder. Li reacts with neutrons and emits alpha rays, which cause the ZnS phosphor to emit light. The photodiode, which is an image pickup element, receives the light emitted from the ZnS phosphor at each of the arranged positions and generates a photocurrent. The thin film transistor (TFT) amplifies the photocurrent output by each photodiode and outputs it to an external terminal. Therefore, since a light current corresponding to the number of neutrons incident on each position of the planar scintillator can be obtained at each external terminal, an image can be acquired by reproducing the signal of each external terminal in a two-dimensional array. To.

FIG. 6 is another example of the detector 5. In FIG. 6, the sample is illustrated together with the detector 5. The detector 5 has a planar phosphor and a detector box. The phosphor, also called a scintillator screen, is provided in the window on one side of the detection box. However, the pinhole collimator 4 illustrated in FIG. 4 is omitted in FIG. Further, although omitted in FIG. 6, the sample is placed on the sample table. The sample table has, for example, a rotary stage, and holds the sample to be inspected rotatably. The neutrons incident on the sample, after being scattered by the sample, pass through the hole of the pinhole collimator 4 (see FIG. 4) and are incident on the phosphor. The incident neutron causes the phosphor to emit light at the incident position of the phosphor. The light emitted on the phosphor is incident on the mirror through the window, reflected by the mirror, and incident on a camera having an image pickup device such as a Charge Coupled Device (CCD). The camera outputs the captured image (the image generated by the light emission on the phosphor) to the outside. In FIG. 6, the camera is provided on the moving stage, and its position can be adjusted. Further, the camera may use a Complementary Metal-Oxide-Semiconductor (CMOS) image sensor instead of the CCD.

The neutron detector 5 is not limited to the configurations shown in FIGS. 5 and 6. The detector 5 is not particularly limited as long as it can capture a two-dimensional neutron transmission image. That is, examples of the detector 5 include a flat panel detector, a neutron camera, a neutron film, a neutron imagen plate, a gas detector, a scintillation detector, and the like.

(Action)
FIG. 7 is a diagram illustrating the first action of the first embodiment of the present invention in comparison with the comparative example. The image pickup device of the comparative example has a neutron source, a moderator, a collimator, a detector, and a shielding material. As shown in the upper part of FIG. 7, in the configuration of the comparative example, a neutron beam traveling in a direction close to a parallel beam is formed by a collimator, and the neutron beam is irradiated to the inspection object to acquire an image. That is, in the configuration of the comparative example, the neutron that has passed through the hole of the collimator is irradiated to the inspection object, scattered by the inspection object, and incident on the detector. In this case, the size of the hole of the collimator is smaller than that of the object to be inspected, and the neutron passing through the hole of the collimator travels in a direction close to the parallel beam. Therefore, the distance between the collimator and the detector becomes large in order to image the entire inspection object. That is, the L / d may be 100 or more in the dimension d of the hole of the collimator and the distance L between the collimator and the detector, and the size of the device is increased.

Further, in the configuration of the comparative example, the neutrons decelerated by the moderator are scattered irregularly and leak from the moderator. As a result, the efficiency of extracting neutrons that pass through the collimator and head toward the inspection target decreases, and improvement in image quality cannot be expected.

On the other hand, according to the configuration of the first embodiment in the lower part of FIG. 7, it is not necessary to form a neutron beam close to a parallel beam by the pinhole collimator 4. Therefore, it is sufficient that the inspection target is within the field of view of the pinhole collimator 4, and the distance between the inspection target and the pinhole collimator 4 is approximately on the order of the size of the inspection target. Further, it is sufficient that the detector 5 fits in the field of view of the pinhole collimator 4, and the distance between the pinhole collimator 4 and the detector 5 is approximately on the order of the size of the detector 5. Therefore, in the first embodiment, the dimensions of the portion including the inspection object, the pinhole collimator 4 and the detector 5 can be made smaller than those in the comparative example. According to the inventor's assumption, the overall size of the image pickup apparatus 10 from the neutron reflector 2 to the detector 5 can be about 2 m.

Further, in the first embodiment, since at least a part of the surface surrounding the moderator 3 and the inspection object is covered with the neutron reflector 2, the neutrons leaking from the moderator 3 are reflected and directed toward the inspection object. You can make it go. Therefore, in the first embodiment, as compared with the comparative example, even if the pinhole collimator 4 is used, the sensitivity of the neutron obtained by the detector 5 is increased and the image quality is improved.

FIG. 8 is a diagram illustrating a second action of the first embodiment of the present invention in comparison with a comparative example. In the comparative example, the size of the inspection object is limited by the size of the detector. For example, the maximum sensitive area of the detector is about 30 cm in length and width. Therefore, it is difficult to image a large inspection object having a large size, for example, a machine such as an automobile, a device, or an entire door of an automobile which is a component thereof.

On the other hand, in the configuration of the first embodiment, if the distance from the inspection object to the pinhole collimator 4 is on the order of the size of the inspection object, a large inspection object can be sufficiently viewed by the pinhole collimator 4. Can be stored in. Further, the distance from the pinhole collimator 4 to the detector 5 does not depend on the size of the inspection object. Therefore, the image pickup apparatus 10 of the first embodiment can image a large inspection object, for example, an object having a length and width of 1 m (such as a door of an automobile) with a device configuration having relatively small dimensions.

FIG. 9 illustrates other features of the image pickup apparatus 10 according to the first embodiment. First, it is desirable that the neutron source 1 is out of the field of view of the camera formed by the pinhole collimator 4 and the detector 5. That is, it is desirable that the neutron source 1 is arranged outside the camera. In this case, the number of neutron sources 1 is not limited. Further, although omitted in the first embodiment of FIGS. 7 to 9, an opening is opened in the outer surface of the neutron reflector 2 on the side where the neutron is incident from the neutron source 1, and the neutron is the moderator 3. It should be easy to introduce to.

The dimensions of the moderator 3 are, for example, a rectangular parallelepiped or other structure having a side of about 20 cm to 300 cm. The size of the image pickup apparatus portion including the pinhole collimator 4, the detector 5, and the shielding material 6 is, for example, about 5 cm to 100 cm.

(Effect of the first embodiment)
The image pickup apparatus 10 of the first embodiment is formed of an absorbent material that absorbs neutrons, and has holes through which neutrons decelerated by the moderator and transmitted through the object or neutrons scattered in the object can pass through. The pinhole collimator 4 and the detector 5 are provided. Then, the image pickup device 10 takes an image of the object by the detector 5 that detects the neutrons that have passed through the pinhole collimator 4. With such a configuration, the image pickup apparatus 10 can have a compact configuration using neutrons by reducing the dimensions of the pinhole collimator 4, the inspection object, and the detector 5 as compared with the conventional case. It is also possible to provide a packaged image pickup device using neutrons.

Further, in the first embodiment, the pinhole collimator 4 has a minute hole formed in the central portion of a plate-shaped member. Since the plate-shaped member has a structure in which the portion in the vicinity in contact with the hole is thin and the thickness increases as the distance from the hole increases, neutrons passing through the hole suppress the generation of shading on the detection surface of the detector 5. It is distributed. That is, in the detector 5, it is possible to suppress the bias of the distribution of incident neutrons.

Further, in the first embodiment, since the neutron reflector 2 covers at least a part around the moderator 3 and the inspection object, the neutrons leaking from the moderator 3 are suppressed and the inspection object is irradiated. Thermal neutrons can be increased and image quality can be improved.

Further, in the first embodiment, since the neutron source 1 is provided outside the field of view of the image pickup apparatus formed by the hole of the pinhole collimator 4 and the detector 5, unnecessary scattering of neutrons is caused. It is suppressed and neutrons can be efficiently irradiated to the inspection target.

<Second embodiment>
FIG. 10 is a diagram illustrating the configuration of the image pickup apparatus 20 according to the second embodiment of the present invention. In FIG. 20, the configuration of the comparative example is also illustrated. Similar to the image pickup device 10 of the first embodiment, the image pickup device 20 of the second embodiment is formed of a neutron source 1 that generates neutrons and an absorbent material that absorbs neutrons, and is a neutron that has passed through an object. Alternatively, among the pinhole collimeter 4 as a throttle member having a hole through which neutrons scattered in the object can pass, the detector 5 for detecting the neutron that has passed through the hole in the throttle member, and the detector 5. A shielding material 6 that covers the periphery other than the side on which the neutron is incident is provided. However, in the second embodiment, the moderator 3 is not essential. That is, in the second embodiment, the object to be inspected itself has a characteristic of being able to slow down fast neutrons to thermal neutrons. Therefore, the image pickup apparatus of the second embodiment irradiates an object having a portion for decelerating neutrons with neutrons, and detects neutrons scattered from the inspection object and passed through the pinhole collimator 4 by the detector 5. ..

In this configuration, the pinhole collimator 4 and the detector 5 for detecting neutrons are arranged toward the irradiated surface of the inspection object to be irradiated with the neutrons emitted from the neutron source 1. Then, the detector 5 scatters in the direction of reflection from the inspection object and detects neutrons that have passed through the pinhole collimator 4.

In the second embodiment, the inspection target is a large structure such as a bridge. These large structures are constructed, for example, from concrete. Fast neutrons are decelerated by hydrogen atoms existing as water in concrete (Non-Patent Document 4). Therefore, as shown in FIG. 10, even if the image pickup device 20 itself is not used with the moderator and the neutron source 1 directly irradiates the large structure to be inspected with neutrons, the same as in the first embodiment. With the pinhole collimator 4 and the detector 5, defects such as cavities inside the inspection object can be imaged. That is, the neutrons irradiated to the inspection object repeatedly collide with hydrogen atoms and the like, gradually reduce their energy, and a part of them is reflected on the incident side. Therefore, even if the pinhole collimator 4 and the detector 5 are arranged on the side where the neutrons are incident on the inspection object from the neutron source 1 side by side with the neutron source 1, the inspection target is the same as in the first embodiment. You can get an image of the inside of an object.

For example, in the configuration of the comparative example illustrated in FIGS. 7 and 8, a large inspection object such as a bridge cannot be sandwiched between the neutron source and the detector. In the second embodiment, in a large inspection object, the inspection object itself is used as a scatterer, that is, a moderator, and the principle of the pinhole camera is applied as in the first embodiment. , Enables imaging of the inside of a large inspection object. Further, the image pickup apparatus 20 of the second embodiment does not need to sandwich a large inspection object, and has a configuration in which the neutron source 1, the pinhole collimator 4, and the detector 5 are arranged on one surface of the inspection object. .. Therefore, the image pickup apparatus 20 of the second embodiment enables diagnosis by an image of a structure, which has been difficult to observe by a non-destructive method in the past.

The processes and means described in the present disclosure can be freely combined and carried out as long as technical inconsistencies do not occur.

1 Neutron source 2 Neutron reflector 3 Moderator 4 Pinhole collimator 5 Detector 6 Shielding material 10, 20 Imaging device

Claims (9)

Neutron sources that generate neutrons and
Moderators that include at least part of the path from the neutron source to the object irradiated with the neutrons and reduce the energy of the neutrons.
A diaphragm member formed of an absorbent material that absorbs neutrons and having a hole through which neutrons decelerated by the moderator and transmitted through the object or neutrons scattered in the object can pass through.
An imaging device including a detector that detects neutrons that have passed through the holes of the diaphragm member. The one according to claim 1, wherein the diaphragm member has a plate shape, and has a shape in which the thickness of a portion in contact with the hole is the thinnest in the cross section including the central axis of the hole, and the thickness increases as the distance from the hole increases. Imaging device. A claim further comprising a neutron reflector that reflects neutrons generated by the neutron source toward the moderator and the object at a position where the moderator and the object are sandwiched between the throttle member and the detector. The image pickup apparatus according to 1 or 2. The image pickup device according to any one of claims 1 to 3, wherein the neutron source is provided outside the field of view of the image pickup device formed by the hole and the detector. The throttle member and the detector are arranged toward the irradiated surface of the object to be irradiated with the neutrons emitted from the neutron source, and the detector is scattered in the direction of reflection from the object. The imaging device according to claim 1 or 2, which detects neutrons. Neutron sources that generate neutrons and
A diaphragm member having a hole through which a neutron that has passed through an object formed of an absorbent material that absorbs the neutron or a neutron scattered in the object can pass through.
A detector for detecting neutrons that have passed through the hole of the diaphragm member is provided.
The diaphragm member and the detector are arranged toward the irradiated surface of the object to be irradiated with the neutrons emitted from the neutron source, and the object has a property of decelerating the neutrons.
An image pickup device that detects neutrons scattered from an object in a direction of reflection and passing through the diaphragm member by the detector. Generating neutrons with a neutron source and
Reducing the energy of the neutron with a moderator that covers at least part of the path from the neutron source to the object irradiated with the neutron.
A throttle member formed of an absorbent material that absorbs neutrons and has holes through which neutrons can pass, and throttles the flow of neutrons that have been decelerated by the moderator and have passed through the object or scattered in the object. When,
An imaging method for detecting and executing neutrons in a flow focused by the diaphragm member. Placing the diaphragm member and the detector for detecting neutrons toward the irradiated surface of the object to be irradiated with the neutrons emitted from the neutron source.
The imaging method according to claim 7, further comprising detecting neutrons scattered in the direction of reflection from the object. Generating neutrons with a neutron source and
A throttle member formed of an absorbent material that absorbs neutrons and having a hole through which the neutrons can pass and the neutron detector are directed toward the irradiated surface of the object to be irradiated with the neutrons emitted from the neutron source. To place,
The flow of neutrons scattered in the direction of reflection from the object having the property of decelerating the neutrons is throttled by the diaphragm member.
An imaging method for detecting and executing neutrons in a flow focused by the diaphragm member.

Images