JP2001004754A - Radiation detector and its testing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radiation detector for measuring the dose of γ rays or the equivalent weight of the dose that can reduce a detection sensitivity difference over a wide range of energy. SOLUTION: In the radiation detector using a semiconductor detector 8 that can detect radiation, a semiconductor detector 8 can detect light, a lower electrode formed on a surface that opposes the incidence surface of the radiation of the semiconductor detector 8 becomes a transparent electrode for transmitting light, a scintillator layer 11 that is formed so that it is optically connected onto the lower electrode and a reflection layer 18 that is formed so that it covers a surface without any contact with the semiconductor detector 8 of the scintillator layer 11 are provided, and fluorescence being emitted by radiation that enters the scintillator layer 11 via the semiconductor detector 8 is detected by the semiconductor detector 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detector for measuring the dose or dose equivalent of gamma rays and a method of testing the radiation detector, and more particularly to a method for reducing the difference in detection sensitivity over a wide range of energy. is there.

[0002]

2. Description of the Related Art When measuring the dose or equivalent of γ-rays in a nuclear power plant, a facility using an accelerator, etc.
There is a need for a radiation detector that has good photon energy vs. dose sensitivity dependency or photon energy vs. dose equivalent sensitivity dependency (hereinafter abbreviated as photon energy characteristics) over a wide energy range from 0 keV to several MeV.

[0003] Among the radiation detectors, ionization chambers have good photon energy characteristics and high sensitivity can be obtained by increasing the volume. Therefore, ionization chambers are used as detectors for measuring the dose or dose equivalent of γ-rays. Often used. However, this ionization chamber has responded to the recent need for miniaturization by increasing the internal gas pressure.
That is, a radiation detector with high sensitivity per unit volume has been demanded.

Accordingly, among the radiation detectors, CdTe as a compound semiconductor has a large atomic number of 48-52 and stable temperature characteristics up to about 50 ° C., so that it is used as a small radiation detector. There are expectations. However, CdTe has a dependency on the photon energy of the sensitivity (the sensitivity decreases as the energy increases).
And could not be used to cover a wide range of photon energies.

[0005] As an improved example covering such a wide range of photon energy characteristics, one disclosed in Japanese Patent Publication No. Hei 6-27814 has been proposed. FIG. 11 is a diagram showing the structure of a conventional radiation detector. In the figure, 1 is a semiconductor detector, 2 is a holding plate for holding the semiconductor detector 1, 3 is a radiation absorbing filter provided in a dome shape so as to cover the semiconductor detector 1 in the radiation incident direction, and 4 is radiation. These are pores opened in the absorption filter 3.

FIG. 12 is a sectional view showing a detailed structure of the semiconductor detector shown in FIG. In the figure, 5 is CdT
An e-semiconductor, 6 is a negative electrode formed on one surface of the CdTe semiconductor 5, and 7 is a positive electrode formed on the other surface of the CdTe semiconductor 5.

A description will be given of a radiation detection method of the conventional radiation detector configured as described above. First, the semiconductor detector 1 is attached to the holding plate 2 while being electrically insulated.
Biased with DC voltage. When radiation is incident on the semiconductor detector 1 and its energy is absorbed, electrons and holes in its shell are generated in the semiconductor detector 1, and these are collected by the electrodes 7 and 6, respectively, and pulsed. The current flows through, and by detecting this, radiation is detected.

FIG. 13 shows that the thickness of the semiconductor detector 1 is the same, lead is used as the radiation absorbing filter 3, and the thickness (h _{1 to} h ₄ is set. The relationship of the thickness is h ₁ > h ₂ > h ₃
> Becomes a h ₄₎ shows the photon energy characteristics of the resultant parameters. By selecting the thickness of the radiation absorption filter 3 to be, for example, h1, good photon energy characteristics are obtained from 100 keV to ₁ MeV. By providing a large number of pores 4 in the radiation absorption filter 3,
Further, the characteristics in the low energy region of 60 to 100 keV are improved.

[0009]

The conventional radiation detector is constructed as described above, and has good characteristics in an energy range of 60 keV to 1 MeV, but has a photon energy characteristic in an energy range of 1 MeV or more. Can't improve. Therefore, several tens keV to several Me required in nuclear power plants, accelerator utilization facilities, and the like.
There is a problem that it is not possible to detect the energy range up to V with a certain sensitivity. This is apparent from the fact that the difference in detection sensitivity is significantly different in the energy range of 80 keV to 6.5 MeV, as shown in FIG. Incidentally, the photon energy characteristic of CdTe alone is, for example, 80k required at a nuclear power plant.
In the energy range from eV to 6.5 MeV, the difference in sensitivity is about two and a half orders of magnitude.

In addition, since the sensitivity difference is adjusted by providing a radiation absorption filter having an appropriate thickness and improving the energy characteristics by sacrificing the sensitivity in the low energy region, the sensitivity is higher than that of the ionization chamber. There is a problem that the characteristics of the semiconductor detector cannot be fully utilized.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to minimize the sacrifice of sensitivity in a low-energy region and to reduce a detection sensitivity difference over a wide range from low energy to high energy. It is an object of the present invention to provide a radiation detector and a test method of the radiation detector that can be reduced.

[0012]

Means for Solving the Problems Claim 1 according to the present invention.
The radiation detector uses a semiconductor detector that can detect radiation, and the semiconductor detector can detect light, and is formed on a surface opposite to a radiation incident surface of the semiconductor detector. The lower electrode is formed of a transparent electrode that transmits light, and is formed so as to cover a scintillator layer formed to be optically connected to the lower electrode and a surface of the scintillator layer that is not in contact with the semiconductor detector. And a fluorescent layer emitted by radiation penetrating into the scintillator layer through the semiconductor detector.

According to a second aspect of the present invention, there is provided a radiation detector using a semiconductor detector capable of detecting radiation, wherein the scintillator layer is formed of a polyhedral structure, and a plurality of polyhedral structures are provided. On the surface, a semiconductor detector is provided, each semiconductor detector can detect light,
A reflective layer formed so as to cover a surface of the scintillator layer that is not in contact with each semiconductor detector is provided.A lower electrode formed on a surface of each semiconductor detector that is in contact with the scintillator layer is a transparent electrode through which light is transmitted. The respective lower electrodes and the scintillator layer are optically connected to each other, and each semiconductor detector detects fluorescence emitted by radiation penetrating the scintillator layer via each semiconductor detector.

According to a third aspect of the present invention, there is provided the radiation detector according to the first or second aspect, wherein
It is provided with a test pulse light entrance window through which pulse light at the time of testing the radiation detector can be introduced.

According to a fourth aspect of the present invention, there is provided a radiation detector according to any one of the first to third aspects.
A radiation absorbing filter that absorbs a desired amount of radiation in the low energy region so that the detection sensitivity of the radiation in the low energy region and the radiation in the high energy region is equal on the radiation incident surface of the semiconductor detector. is there.

According to a fifth aspect of the present invention, in the radiation detector according to the fourth aspect, the upper electrode on the radiation incident surface side of the semiconductor body is formed of a transparent electrode that transmits light.
The radiation absorption filter includes an upper scintillator layer optically connected to the upper electrode, and an upper reflective layer formed to cover a surface of the upper scintillator layer that is not in contact with the semiconductor detector.

According to a sixth aspect of the present invention, in the radiation detector according to the fourth aspect, the radiation absorbing filter is formed of a hollow electromagnetic shield covering the semiconductor detector.

According to a seventh aspect of the present invention, there is provided a radiation detector as set forth in any of the first to sixth aspects.
The scintillator layer is formed of CaF ₂ (Eu).

The radiation detector according to claim 8 of the present invention is the radiation detector according to any one of claims 1 to 7,
The semiconductor detector is made of CdZnTe.

According to a ninth aspect of the present invention, in the method for testing a radiation detector according to the third aspect, the energy range is set to be different from the energy range of the radiation that needs to be measured by the radiation detector. Test pulse light,
The sound is introduced from the test pulse light incident window to determine the soundness of the radiation detector.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described. FIG. 1 is a sectional view showing a configuration of the radiation detector according to the first embodiment of the present invention. In the figure, reference numeral 8 denotes a semiconductor detector capable of detecting radiation, 9 denotes a radiation absorption filter connected by an adhesive 10 so as to cover the radiation incident surface of the semiconductor detector 8, and has a low energy. It absorbs a desired amount of radiation in the low energy region so that the detection sensitivity of the radiation in the region and the radiation in the high energy region are equal. The radiation absorption filter 9 is connected to a generally adjacent negative electrode (not shown) to fix the potential.

Reference numeral 11 denotes a scintillator layer formed so as to optically connect with an optical bonding material 12 so as to cover a surface opposite to the radiation incident surface of the semiconductor detector 8, and 13 denotes a semiconductor of the scintillator layer 11. The reflective layer formed so as to cover the surface not in contact with the detector 8 can be formed, for example, by applying a white paint to the scintillator layer 11.

FIG. 2 is a sectional view showing details of the semiconductor detector 8 of the radiation detector shown in FIG. Reference numeral 14 denotes a semiconductor capable of detecting radiation and light, and reference numeral 15 denotes a lower electrode formed on a surface of the semiconductor 14 opposite to the radiation incident surface, which is formed of a transparent electrode capable of transmitting light. I have. Reference numeral 16 denotes an upper electrode formed on the radiation incident surface of the semiconductor 14, for example, formed by metal deposition or the like.
A structure that does not transmit light is provided. This is effective because light is incident on the semiconductor detector 8 from the outside and is not measured as noise. When the upper electrode 16 is a negative electrode, for example, the lower electrode 15 is biased to a positive voltage.

Next, Embodiment 1 configured as described above
The principle of detecting radiation by the semiconductor detector 8 in the radiation detector described above is the same as in the conventional case, and a description thereof will be omitted. Here, FIG. 3 shows how to use the radiation absorbing filter 9 and the scintillator layer 11 to obtain a good photon energy characteristic of the radiation detector, and how to determine an appropriate thickness. A description will be given based on the relationship between the photon energy and the relative sensitivity shown above.

First, as for the radiation detector, the semiconductor detector 8 alone has characteristics as shown in a graph A of FIG. As is clear from the figure, since the detection sensitivity in the low-energy region is higher than the detection sensitivity in the high-energy region, a radiation absorption filter is conventionally installed on the radiation incident side of the semiconductor detector, and the low-energy radiation is And the detection sensitivity in the low energy region and the detection sensitivity in the high energy region are adjusted so as to be equal.

However, in this method, the detection sensitivity in the high energy region cannot be improved, and only the detection sensitivity in the low energy region is sacrificed. Therefore, in the present invention, the scintillator layer 11 and the reflection layer 13 are formed on a surface of the semiconductor detector 8 opposite to the radiation incident surface in order to improve the detection sensitivity in the high energy region.

When the scintillator layer 11 is arranged as described above, radiation in a high energy region transmitted through the semiconductor detector 8 emits light at the scintillator layer 11. Then, the fluorescent light is reflected by the reflection layer 13 and is incident on the semiconductor detector 8 via the lower electrode (transparent electrode) 15 of the semiconductor detector 8 which is optically connected. Then, the fluorescence is converted into an electron-hole pair in the semiconductor 14 and detected.

As described above, the radiation in the high energy region transmitted through the semiconductor detector 8 is emitted by the scintillator layer 11 and detected by the semiconductor detector 8, thereby improving the detection sensitivity of the radiation in the high energy region. It is possible to reduce the difference between the radiation sensitivity in the low energy region and the radiation sensitivity in the high energy region.

The actual thickness of the scintillator layer is determined from the relative sensitivity per unit area of the semiconductor detector to each photon energy when this thickness is used as a parameter.
FIG. 3 shows respective characteristics of graphs C1 and C2 in which the thickness of the scintillator layer is different. The thickness relationship is C1> C
2. Here, a scintillator layer having a thickness of C1 and having excellent detection sensitivity for radiation in a high energy region is set.

Next, by providing the scintillator layer 11 on the surface of the semiconductor detector 8 opposite to the radiation incident surface, even if the radiation detection sensitivity in the high energy region is improved, the radiation in the high energy region is improved. Is lower than the detection sensitivity of radiation in the low energy region. Therefore, by forming the radiation absorption filter on the radiation incident surface of the semiconductor detector, the detection sensitivity in the low energy region and the detection sensitivity in the high energy region are adjusted to be equal.

The actual thickness of the radiation absorbing filter (for example, using lead) is determined from the relative sensitivity per unit area of the semiconductor detector 8 to each photon energy when this thickness is used as a parameter. FIG. 3 shows respective characteristics of graphs B1 and B2 in which the thickness of the radiation absorbing filter is different. The relationship of the thickness is B1 <B2. Here, a radiation absorption filter having a thickness of B1 is set so as to be equal to the radiation sensitivity in the high energy region adjusted as described above.

By forming the radiation absorption filter 9 in this way, the detection sensitivity in the low energy region and the detection sensitivity in the high energy region can be adjusted to be equal. Finally, the characteristic as the radiation detector has the characteristic of B1 + C1 as shown in the graph D of FIG.

In the radiation detector of the first embodiment configured as described above, the scintillator layer 11 is formed on the surface of the semiconductor detector 8 opposite to the radiation incident surface, and the height of the radiation transmitted through the semiconductor detector 8 is increased. Since the radiation in the energy region is converted into fluorescent light and the light is detected by the semiconductor detector 8, the detection sensitivity of the radiation in the high energy region can be improved, and the detection sensitivity of the radiation in the low energy region can be improved. When,
It is possible to reduce the difference from the radiation sensitivity in the high energy region.

Further, since the radiation absorption filter 9 is formed on the radiation incident surface of the semiconductor detector 8, the radiation absorption filter 9 is formed.
The detection sensitivity of the radiation in the low energy region and the detection sensitivity of the radiation in the high energy region can be uniformly adjusted with a value obtained by improving the detection sensitivity of the radiation in the high energy region.

Embodiment 2 In the first embodiment, an example is shown in which the semiconductor detector is formed only on one direction surface. However, the present invention is not limited to this. For example, as shown in FIG. 4, a polyhedral scintillator layer 17 is formed, Semiconductor detectors 8 are provided on a plurality of surfaces of scintillator layer 17 in the same manner as in the first embodiment, and lower electrodes (not shown) formed on the surfaces of semiconductor detectors 8 that are in contact with polyhedral scintillator layer 17 are provided. Each of the lower electrodes is optically connected to the scintillator layer.

At this time, it is desirable that the semiconductor detector 8 is formed on the entire surface of the polyhedral scintillator layer 17 as much as possible. However, the surface of the polyhedral scintillator layer 17 which is not in contact with each semiconductor detector 8 is It is desirable to form a reflective layer (not shown) so as to cover the surface.

The radiation detector according to the second embodiment configured as described above has the same effect as that of the first embodiment, and can expand the radiation detection area (solid angle). In addition, direction dependency in radiation detection can be reduced.

Embodiment 3 FIG. 5 is a sectional view showing a configuration of a radiation detector according to Embodiment 3 of the present invention, and FIG. 6 is a sectional view showing details of a semiconductor detector of the radiation detector shown in FIG. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof will be omitted. 18 is a semiconductor detector capable of detecting radiation, and 19 is a semiconductor detector 1
8, an upper scintillator layer 20 optically connected to the semiconductor detector 18 by an optical bonding material 21 with a radiation absorbing filter formed so as to cover the radiation incident surface of No. 8 and a semiconductor of the upper scintillator layer 20. And an upper reflective layer 22 formed so as to cover a surface not in contact with the detector 18.

As shown in FIG. 6, the semiconductor detector 18 is a semiconductor 2 capable of detecting radiation and light.
3. It comprises a lower electrode 24 and an upper electrode 25 formed below and above the semiconductor 23. These two electrodes 2
Reference numerals 4 and 25 are formed of transparent electrodes through which light can pass.

Next, the third embodiment configured as described above
The radiation absorption filter 19 of the radiation detector will be described. Other operations are the same as those in the above-described embodiments, and thus description thereof is omitted. Here, the upper scintillator layer 20 was used as the radiation absorption filter 19. This serves to adjust the upper scintillator layer 20 so that the radiation detection sensitivity in the low energy region and the radiation detection sensitivity in the high energy region are equal, as in the above embodiments.

The relative sensitivity of the upper scintillator layer 20 to the photon energy per unit area of the semiconductor detector is shown in a graph E of FIG. As shown in this figure, since the upper scintillator layer 20 also plays a role of detecting radiation in addition to the above-mentioned role, the characteristics of the graph D of the radiation detector formed in the first embodiment are shown in FIG. It is possible to obtain a characteristic as shown in a graph F in which the detection sensitivity (graph E) is added.

The third embodiment configured as described above,
Since the radiation absorbing filter 19 is formed by the upper scintillator layer 20, the radiation absorbing filter 19 functions as it is, and by detecting a part of the radiation, the detection sensitivity and the high sensitivity of the radiation in the low energy region are improved. The detection sensitivity of the radiation in the energy region can be adjusted more evenly.

Embodiment 4 FIG. FIG. 8 is a sectional view showing a configuration of the radiation detector according to the fourth embodiment of the present invention. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof will be omitted. 13a is formed on the reflection layer 13;
This is a test pulse light entrance window into which pulse light at the time of testing the radiation detector can be introduced.

Conventionally, when testing a radiation detector,
The presence or absence of detection of radiation is determined by using a radiation source, and there is a risk in handling this radiation source. However, it is possible to easily check the soundness of the semiconductor detector 8 by providing the test pulse light incident window 13a and, for example, causing the photodiode to emit light at a constant frequency by remote control and introducing the photodiode through the test pulse light incident window 13a. Can be.

If the intensity of the test pulse light is set outside the energy range which needs to be actually measured,
During the test, the actual measurement can be performed without interruption, and the soundness of the radiation detector can be confirmed while measuring.

Embodiment 5 FIG. FIG. 9 is a sectional view showing a configuration of the radiation detector according to the fifth embodiment of the present invention. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 26 denotes a hollow electromagnetic shield that covers the semiconductor detector 8 and serves as a substitute for the radiation absorption filter described in the first embodiment. The electromagnetic shield 26 can be formed by using a conductive material such as copper or aluminum and setting it to an appropriate thickness.

As described above, the provision of the electromagnetic shield 26 not only exhibits the effect of the radiation absorption filter as in the above-described embodiments, but also the electromagnetic shield 2.
Since it also serves as 6, the entire potential of the radiation detector can be stably operated. Therefore, the exclusive configuration as the radiation absorption filter can be reduced, and the structure can be simplified.

In each of the above embodiments, the substance used for the semiconductor of each semiconductor detector is not specifically described, but it goes without saying that any substance that can detect radiation and light can be used. Instead, for example, a semiconductor detector may be formed using CdTe or CdZnTe as a semiconductor having an atomic number of 30 or more. If formed in this way, as shown in FIG. 10, the sensitivity of CdTe starts to decrease at a temperature of about 50 ° C. or more, so that the sensitivity characteristic ± 10% practically required is satisfied up to about 60 °. It is.

CdZnTe can be used up to about 100 degrees and can be used in a higher temperature environment than CdTe. Therefore, for example, it is suitable for use of a radiation detector or the like which is installed in close proximity to a place where an object to be measured may become hot at the time of an accident, such as an exhaust gas monitor for an accident. Further, although CdZnTe itself has a somewhat lower detection sensitivity in the low energy region than CdTe itself, it is detected with the same sensitivity by forming a radiation absorption filter, so that the thickness of the radiation absorption filter can be reduced. it can.

In each of the above embodiments, the substance used for each scintillator layer is not specifically described. However, if it is formed of CaF ₂ (Eu), this substance can be used for other general scintillators. Since it is chemically and physically stable as compared with a substance that does not need to be placed in a closed container or a protective container, each scintillator layer can be formed with an inexpensive configuration.

[0051]

As described above, according to the first aspect of the present invention, in a radiation detector using a semiconductor detector capable of detecting radiation, the semiconductor detector can detect light, and the semiconductor detector can detect light. The lower electrode formed on the surface opposite to the radiation incident surface of the detector is formed of a transparent electrode that transmits light, and a scintillator layer formed so as to be optically connected to the lower electrode, and a scintillator layer. A reflective layer formed so as to cover a surface not in contact with the semiconductor detector, and the semiconductor detector detects fluorescence emitted by radiation penetrating the scintillator layer through the semiconductor detector, so that high energy It is possible to provide a radiation detector capable of improving the detection sensitivity of radiation in a region.

According to a second aspect of the present invention, in the radiation detector using the semiconductor detector capable of detecting radiation, the scintillator layer is formed of a polyhedral structure, and is provided on a plurality of surfaces of the polyhedron. A semiconductor detector, each semiconductor detector can detect light, and a reflective layer formed to cover a surface of the scintillator layer that is not in contact with each semiconductor detector, the scintillator of each semiconductor detector The lower electrode formed on the surface in contact with the layer is formed of a transparent electrode through which light is transmitted, and each lower electrode and the scintillator layer are optically connected, and the radiation that has entered the scintillator layer via each semiconductor detector. Fluorescence emitted by is detected by each semiconductor detector, so that the detection sensitivity of radiation in the high-energy region can be improved and the direction dependency in radiation detection is reduced. It is possible to provide a radiation detector capable of.

According to a third aspect of the present invention, in the first or second aspect, the reflection layer is provided with a test pulse light incident window through which pulse light can be introduced at the time of testing the radiation detector. In addition, it is possible to provide a radiation detector that can easily perform a test of the radiation detector.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the radiation of the low energy region and the radiation of the high energy region are formed on the radiation incident surface of the semiconductor detector. A radiation absorption filter that absorbs a desired amount of radiation in the low-energy region so that the detection sensitivity of the radiation is uniform is improved, so that the detection sensitivity of the radiation in the high-energy region is improved, It is possible to provide a radiation detector that can equalize the radiation detection sensitivity.

According to a fifth aspect of the present invention, in the fourth aspect, the upper electrode on the radiation incident surface side of the semiconductor body is formed of a transparent electrode that transmits light, and the radiation absorption filter is An upper scintillator layer optically connected to the upper electrode, and an upper reflective layer formed so as to cover a surface of the upper scintillator layer that is not in contact with the semiconductor detector, so that a low energy region and a high energy region It is possible to provide a radiation detector that can further equalize the radiation detection sensitivity.

According to the sixth aspect of the present invention, in the fourth aspect, since the radiation absorbing filter is formed by a hollow electromagnetic shield covering the semiconductor detector, the radiation absorbing filter operates in a state where the potential is stable. It is possible to provide a radiation detector that can perform the measurement.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, since the scintillator layer is formed of CaF ₂ (Eu), it is chemically and physically. It is possible to provide a radiation detector that is stable and can simply form the structure of the scintillator layer.

According to the eighth aspect of the present invention, in any one of the first to seventh aspects, since the semiconductor detector is formed of CdZnTe, the radiation can operate stably in a high temperature environment. It is possible to provide a detector.

According to a ninth aspect of the present invention, in the radiation detector testing method according to the third aspect, the energy range is set to be different from the energy range of the radiation that needs to be measured by the radiation detector. Since the test pulse light is introduced from the test pulse light entrance window to determine the soundness of the radiation detector, it is possible to determine the soundness of the radiation detector without interrupting the measurement of the radiation detector. It is possible to provide a test method for a vessel.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a radiation detector according to a first embodiment of the present invention.

FIG. 2 is a sectional view for explaining details of a semiconductor detector of the radiation detector shown in FIG. 1;

FIG. 3 is a diagram illustrating a relationship between photon energy and relative sensitivity when the thickness of a radiation absorbing filter and the thickness of a scintillator layer for forming the radiation detector illustrated in FIG. 1 are each used as a parameter.

FIG. 4 is a perspective view showing a configuration of a radiation detector according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of a radiation detector according to a third embodiment of the present invention.

6 is a cross-sectional view for explaining details of a semiconductor detector of the radiation detector shown in FIG. 5;

FIG. 7 is a diagram showing a relationship between photon energy and relative sensitivity of the radiation detector shown in FIG.

FIG. 8 is a sectional view showing a configuration of a radiation detector according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing a configuration of a radiation detector according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing the relationship between the temperature and the relative sensitivity of each substance of the semiconductor detector.

FIG. 11 is a cross-sectional view illustrating a configuration of a conventional radiation detector.

12 is a cross-sectional view illustrating a configuration of a semiconductor detector of the radiation detector illustrated in FIG.

13 is a diagram illustrating a relationship between photon energy and relative sensitivity when the thickness of a radiation absorption filter for forming the radiation detector illustrated in FIG. 11 is used as a parameter.

[Explanation of symbols]

8, 18 Semiconductor detector, 9, 19 Radiation absorption filter, 10 Adhesive, 11 Scintillator layer, 12, 21
Optical bonding material, 13 Reflective layer, 13a Test pulse light incident window, 14, 23 Semiconductor, 15, 24 Lower electrode, 1
6, 25 upper electrode, 17 polyhedral scintillator layer, 2
0 Upper scintillator layer, 22 Upper reflective layer, 26 Electromagnetic shield.

Claims (9)

[Claims] 1. A radiation detector using a semiconductor detector capable of detecting radiation, wherein the semiconductor detector is capable of detecting light, and is provided on a surface of the semiconductor detector opposite to an incident surface of the radiation. The formed lower electrode is a transparent electrode that transmits the light, and a scintillator layer formed to be optically connected to the lower electrode, and a surface of the scintillator layer that is not in contact with the semiconductor detector. A reflective layer formed so as to cover the semiconductor detector, and wherein the semiconductor detector detects fluorescence emitted by radiation that has entered the scintillator layer via the semiconductor detector. 2. A radiation detector using a semiconductor detector capable of detecting radiation, wherein the scintillator layer is formed of a polyhedral structure, and the scintillator layer is formed on a plurality of surfaces of the polyhedron.
The semiconductor detector includes the semiconductor detector, each of the semiconductor detectors can detect light, and includes a reflective layer formed so as to cover a surface of the scintillator layer that is not in contact with the semiconductor detector. A lower electrode formed on a surface of the detector that is in contact with the scintillator layer is formed of a transparent electrode through which the light passes, and each of the lower electrodes and the scintillator layer are optically connected, and the scintillator layer is A radiation detector characterized in that fluorescence emitted by radiation entering through each semiconductor detector is detected by each semiconductor detector. 3. The radiation detector according to claim 1, wherein the reflection layer is provided with a test pulse light incident window through which pulse light at the time of testing the radiation detector can be introduced. 4. A radiation absorbing a desired amount of radiation in the low-energy region so that the detection sensitivity of the radiation in the low-energy region and the radiation in the high-energy region are equal on the radiation incident surface of the semiconductor detector. The radiation detector according to claim 1, further comprising an absorption filter. 5. An upper electrode on a radiation incident surface side of a semiconductor detector formed of a transparent electrode that transmits light, and as a radiation absorbing filter, an upper scintillator layer optically connected to the upper electrode, The radiation detector according to claim 4, further comprising: an upper reflective layer formed to cover a surface of the upper scintillator layer that is not in contact with the semiconductor detector. 6. The radiation detector according to claim 4, wherein the radiation absorption filter is formed by a hollow electromagnetic shield covering the semiconductor detector. 7. The radiation detector according to claim 1, wherein the scintillator layer is formed of CaF ₂ (Eu). 8. The radiation detector according to claim 1, wherein the semiconductor detector is made of CdZnTe. 9. The test method for a radiation detector according to claim 3, wherein the test pulse light set in an energy range different from the energy range of the radiation that needs to be measured by the radiation detector is a test pulse light. A method for testing a radiation detector, comprising determining the soundness of the radiation detector by introducing the radiation detector from an entrance window.