JP2001305233A - Gamma-ray source image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To visualize a spatial distribution of gamma-ray sources. SOLUTION: In this image pickup device, a pinhole as a gamma-ray incidence hole is bored in the front face center of a lead casing 1, while a gamma-ray detector 3 comprising vertically and horizontally arranged scintillation counters 4 is provided in a rear wall side position inside the casing 1. A monitor 5 is connected to the gamma-ray detector 3. When some scintillation counter 4 detects a gamma ray emitted from the gamma-ray source, the scintillation counter 4 is displayed on the monitor 5 to visualize the vertical and horizontal spatial distribution of the gamma-ray sources.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a gamma ray source imaging apparatus used for visualizing the spatial distribution of a gamma ray source.

[0002]

2. Description of the Related Art When performing work in a place where there is a risk of being contaminated with a gamma ray source, such as when dismantling a nuclear power plant, the worker is prevented from being exposed to radiation, and the gamma ray source is decontaminated or contained. Therefore, it is necessary to clarify the location of the gamma ray source, for example, where in the room is contaminated with the gamma ray source.

Conventionally, gamma rays have been detected using a scintillation counter or the like as a gamma ray sensor.

[0004]

However, when a gamma ray sensor is used to detect a gamma ray, it is difficult to visualize the spatial distribution of the gamma ray source, although it is possible to confirm the presence or absence of the gamma ray source. It was difficult to determine where the gamma-ray source was emitted, where it was contaminated, and where the gamma-ray source was.

Accordingly, an object of the present invention is to provide a gamma ray source imaging apparatus capable of easily visualizing the spatial distribution of the gamma ray source so that the location of the gamma ray source can be easily specified.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a case having a gamma ray incident hole at the center of the front surface of a case having a gamma ray shielding function. At the rear side wall, a gamma ray detector is provided with gamma ray sensors arranged vertically and horizontally, and a monitor connected to the gamma ray detector is provided.The gamma ray incident from the gamma ray entrance hole is imaged by the gamma ray detector and visualized on the monitor. Configuration.

When a gamma ray emitted from a gamma ray source enters the housing through a gamma ray entrance hole, the gamma ray is detected and imaged by one of the gamma ray sensors of the gamma ray detector, and the spatial distribution of the gamma ray source is easily visualized on a monitor. The location of the gamma ray source can be easily specified.

[0008] Further, by providing a filter which transmits only a gamma ray having energy equal to or more than a predetermined value in front of the gamma ray detection device in the housing,
Unnecessary energy incident on the gamma ray detector can be removed, and the lower limit of the energy level of the gamma ray source whose spatial distribution is to be detected can be set.

Further, by making the filter detachable, the work of confirming the location of the gamma ray source is performed while replacing the filter with a filter having a different energy level to be transmitted. It is possible to confirm the location while separating the energy levels for each held energy level, and to obtain energy information for each gamma ray source.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 (a) and 1 (b) show an embodiment of a gamma ray source imaging apparatus according to the present invention. For example, one side has a rectangular parallelepiped shape of about 30 cm and a top is provided with a lid 1a which can be opened and closed. A needle hole serving as a gamma ray incident hole 2 is formed in the center of the front surface of a lead case 1 having a gamma ray shielding capability. 1 is provided with a gamma ray detecting device 3 for detecting a gamma ray incident thereon. The gamma ray detecting device 3 has a configuration in which scintillation counters 4 as gamma ray sensors are vertically and horizontally arranged and integrated. Further, a monitor 5 is connected to the gamma ray detecting device 3, and any one of the scintillation counters 4 of the gamma ray detecting device 3 detects a gamma ray so that an image of the gamma ray is picked up and visualized on the monitor 5. Further, the lower limit of the energy level of the gamma ray to be transmitted to the gamma ray detecting device 3 by transmitting only the gamma ray having energy equal to or more than a predetermined value to the front side of the gamma ray detecting device 3 in the housing 1 can be limited. The filter 6 is detachably installed.

As shown in FIG. 1A, the gamma ray incident hole 2 has a conical shape in which the outside diameter is increased by a required dimension from the inside in the thickness direction, and spreads in the vertical and horizontal directions in front of the lead casing 1. When a gamma ray source is present in a predetermined space, gamma rays emitted from the gamma ray source can be made incident on the inside of the housing 1 and received by the gamma ray detection device 3 to be imaged.

The principle of the gamma ray source imaging device will be described with reference to FIG.

As a model of the gamma ray source distributed in the space, for example, the extension of the axis of the gamma ray entrance hole 2 in a plane space facing the housing 1 at a required distance in front of the housing 1. The gamma ray source A exists on the line, and the upper position, the lower position,
Gamma-ray sources B, C,
Assume that D and E are present.

Since gamma rays usually have straightness,
Gamma ray source A on an extension of the axis of gamma ray entrance 2
The gamma ray 7a emitted from the gamma ray incident hole 2 passes along the axis and enters the lead case 1, and is detected by the scintillation counter 4a arranged at the center position of the gamma ray detecting device 3. Is imaged.

A gamma ray 7b radiated from a gamma ray source B located above an extension of the axis of the gamma ray entrance 2
Is incident into the lead case 1 through the gamma ray entrance hole 2,
The image is detected and imaged by a scintillation counter 4b arranged in the lower center of the gamma ray detecting device 3.

Further, a gamma ray 7 radiated from a gamma ray source C located below an extension of the axis of the gamma ray entrance 2
The light c enters the lead case 1 through the gamma ray incident hole 2 and is detected and imaged by a scintillation counter 4c arranged at the upper center of the gamma ray detecting device 3.

Similarly, a gamma ray 7d emitted from a gamma ray source D located on the right side of the extension of the axis of the gamma ray entrance hole 2 enters the lead case 1 through the gamma ray entrance hole 2 and detects the gamma ray. A gamma ray 7e, which is detected by a scintillation counter 4d arranged at the left end in the vertical direction of the device 3 and emitted from a gamma ray source E located to the left of an extension of the axis of the gamma ray entrance 2, is a gamma ray. The light enters the lead case 1 through the incident hole 2, and is detected by the scintillation counter 4 e disposed at the right end in the vertical center of the gamma ray detection device 3, so that each image is captured.

Thus, the gamma ray sources A, B, C, D,
Gamma rays 7a, 7b, 7c, 7d, 7 emitted from E
e denotes different scintillation counters 4a, 4b, 4c, 4 in the gamma ray detecting device 3 according to the spatial arrangement of the gamma ray sources A, B, C, D, E in the vertical and horizontal directions.
In this case, the arrangement of the scintillation counters 4a, 4b, 4c, 4d, and 4e in the vertical and horizontal directions is based on the spatial arrangement of the gamma ray sources A, B, C, D, and E. This is reflected in a state where the upper, lower, left, and right sides are inverted with respect to the axis 2. Therefore, the scintillation counters 4a, 4b, 4
images 4a 'in which the up, down, left, and right directions of c, 4d, 4e are inverted.
When the images 4b ', 4c', 4d ', and 4e' are respectively displayed, the arrangement of the images 4a ', 4b', 4c ', 4d', and 4e 'on the monitor 5 is such that the gamma ray sources A, B, C,
The spatial distribution in the vertical and horizontal directions of D and E is well matched.

Therefore, the gamma ray source imaging apparatus of the present invention is installed in, for example, a room where there is a possibility that the gamma ray source is contaminated, and any one of the scintillation counters 4 is installed.
When a gamma ray is detected and captured, an image in which the vertical and horizontal directions of the scintillation counter 4 are inverted is displayed on the monitor 5 so that the spatial arrangement of the gamma ray source in the vertical and horizontal directions can be easily visualized. The gamma ray source in the room can be easily identified.

Further, since the gamma ray incident on the gamma ray detecting device 3 can be limited to only the gamma ray having the energy equal to or more than the predetermined value by the filter 6, unnecessary energy is removed and the strong gamma ray having the energy level equal to or higher than the predetermined energy level is removed. The location of the gamma ray source to be emitted can be clarified, and furthermore, by performing the work of confirming the location of the gamma ray source while replacing the filter 6 in the housing 1 with a filter 6 having a different energy level of the transmitted gamma ray,
When there are a plurality of gamma ray sources, the location can be confirmed while classifying each gamma ray source according to its own energy level, and energy information for each gamma ray source can be obtained.

Next, FIG. 3 shows an application example of the above-described embodiment. In a gamma ray source image pickup device having a configuration similar to that shown in FIG. At the position near the hole 2, the gamma ray incident hole 2
A camera 8 such as a CCD camera having substantially the same angle of view as the angle of the apex of the conical shape formed by the camera is installed, and an image captured by the camera 8 and a gamma ray are detected and captured in the same manner as described above. A combination device 9 is provided for combining an image obtained by inverting the scintillation counter 4 in the up / down / left / right direction and displaying the image on the monitor 5 at the same time. When the image of the camera 8 is combined with the image of the scintillation counter 4 capturing the gamma ray, for example, the image of the scintillation counter 4 is marked by a mark in the image of the camera 8 displayed on the monitor 5. What is necessary is just to make it display by changing a color, lightness, etc., and the same thing as what was shown in FIG. 1 is attached | subjected to the same code | symbol.

According to the present embodiment, on the monitor 5,
The spatial arrangement of the gamma ray source can be displayed by superimposing it on the image of the real object in the space in front of the gamma ray entrance hole 2 captured by the camera 8, and the location of the gamma ray source can be more easily specified in relation to the object. can do.

The present invention is not limited to the above embodiment. The gamma ray detecting device 3 is shown as having a rectangular external shape in which the scintillation counters 4 are vertically and horizontally integrated. In this case, the lead casing 1 may have a cylindrical shape extending in the front-rear direction, and the scintillation counter 4 may be used as a gamma ray sensor integrated vertically and horizontally to constitute the gamma ray detecting device 3. However, if it is possible to detect and image gamma rays independently,
Other types of gamma ray sensors may be used, and if the spatial arrangement of all gamma ray sources is to be clarified, the filter 6 may not be provided. It goes without saying that various changes can be made in.

[0025]

As described above, according to the gamma ray source imaging apparatus of the present invention, a needle hole serving as a gamma ray incident hole is formed in the center of the front surface of a casing having a gamma ray shielding function, and the inside of the casing is formed. At the rear side wall, a gamma ray detector is provided with gamma ray sensors arranged vertically and horizontally, and a monitor connected to the gamma ray detector is provided.The gamma ray incident from the gamma ray entrance hole is imaged by the gamma ray detector and visualized on the monitor. When the gamma ray emitted from the gamma ray source enters the housing through the gamma ray entrance hole, the gamma ray source differs in the gamma ray detection device according to the arrangement of the gamma ray source in the vertical and horizontal directions in the space. Since images can be detected and detected by the gamma ray sensor, if any gamma ray sensor of the gamma ray detector detects gamma rays, In addition, by displaying the gamma ray sensor on the monitor, the spatial distribution of the gamma ray source in the vertical and horizontal directions can be easily visualized, and the location of the gamma ray source can be easily specified. In addition, by adopting a configuration in which a filter that transmits only gamma rays having energy equal to or more than a predetermined value is disposed on the front side of the gamma ray detection device in the housing,
Unnecessary energy incident on the gamma ray detection device can be removed, and the lower limit of the energy level of the gamma ray source to be detected can be set. Filter
By performing the work of confirming the location of the gamma ray source while replacing it with a filter having a different energy level to be transmitted, it is possible to confirm the location while separating a plurality of gamma ray sources for each of the energy levels possessed by the gamma ray source. This has the effect that it is also possible to obtain energy information for each.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a gamma ray source imaging apparatus according to the present invention, in which (a) is a schematic cut-away side view, and (b) is a partially cut-away schematic front view.

FIG. 2 is a schematic diagram showing the principle of the gamma ray imaging device of the present invention.

FIG. 3 is a schematic cross-sectional side view showing an application example of the gamma ray imaging device of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lead housing 2 Gamma ray entrance hole 3 Gamma ray detecting device 4, 4a, 4b, 4c, 4d, 4e Scintillation counter (gamma ray sensor) 5 Monitor 6 Filter 7a, 7b, 7c, 7d, 7e Gamma ray

Claims (3)

[Claims] 1. A gamma ray detecting device in which a needle hole serving as a gamma ray incident hole is formed in the center of the front surface of a casing having a gamma ray shielding ability, and gamma ray sensors are arranged vertically and horizontally at a position on the rear wall side in the casing. Further comprising a monitor connected to the gamma ray detecting device, wherein the gamma ray incident from the gamma ray incidence hole is imaged by the gamma ray detecting device and visualized by the monitor. . 2. The gamma ray source imaging apparatus according to claim 1, wherein a filter that transmits only gamma rays having energy equal to or greater than a predetermined value is disposed in front of the gamma ray detection device in the housing. 3. The gamma ray source imaging device according to claim 2, wherein the filter is detachable.