JP2021046462A - Radiation detecting material and radiation detector - Google Patents

Abstract

To provide a radiation detecting material having a short fluorescence life, and a radiation detector.SOLUTION: According to an embodiment, a radiation detecting material contains a composition. The composition contains a crystal having a garnet structure. The crystal contains a first element M containing at least one selected from the group consisting of Ca, Sr, Ba and Mg. The crystal has the composition of (Lu1-x-y-zGdxMyCez)3+v(Al1-uGau)5O12-w, 0≤x≤0.5, 0<y≤0.05, 0<z≤0.05, 0.3≤u≤0.7, -0.1≤v≤0.1, -0.1≤w≤0.1.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to radiation detection materials and radiation detection devices.

For example, a scintillator is used for a radiation detector. It is desired that the scintillator has a short fluorescence lifetime.

E. V. D. van Loefet al. , "Scintillation properties of LaBr3: Ce3 + crystals: fast, effective and high-energy-resolution scintillators," Nucl. Instr. and Meth. A 486 (2002) 254-258.

Embodiments of the present invention provide a radiation detection material and a radiation detection device having a short fluorescence lifetime.

According to embodiments of the present invention, the radiation detection material comprises a composition. The composition comprises crystals having a garnet structure. The crystals contain a first element M containing at least one selected from the group consisting of Ca, Sr, Ba and Mg. The _{crystals, (Lu 1-x-y} -z Gd x M y Ce z) 3 + v (Al 1-u Ga u) 5 O 12-w, 0 ≦ x ≦ 0.5,0 <y ≦ 0.05 , 0 <z ≦ 0.05, 0.3 ≦ u ≦ 0.7, −0.1 ≦ v ≦ 0.1, −0.1 ≦ w ≦ 0.1.

FIG. 1 is a graph illustrating the characteristics of a radiation detection material. FIG. 2 is a graph illustrating the characteristics of the radiation detection material. FIG. 3 is a schematic view illustrating the radiation detection device according to the second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between the parts, etc. are not always the same as the actual ones. Even if the same part is represented, the dimensions and ratios of each may be represented differently depending on the drawing.
In the present specification and each figure, the same elements as those described above with respect to the above-mentioned figures are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

(First Embodiment)
The radiation detection material according to the embodiment includes a composition. The composition comprises crystals having a garnet structure. Crystals are, for example,
_{(Lu 1-x-y-} z Gd x M y Ce z) 3 + v (Al 1-u Ga u) 5 O 12-w ... (1)
0 ≦ x ≦ 0.5,
0 <y ≤ 0.05,
0 <z ≤ 0.05,
0.3 ≤ u ≤ 0.7,
-0.1 ≤ v ≤ 0.1,
-0.1 ≤ w ≤ 0.1,
Has the composition of.

The first element M comprises at least one selected from the group consisting of Ca, Sr, Ba and Mg. The concentration ratio y / z of the first element M to Ce is preferably 0.1% or more and 50% or less, for example. The concentration described in the embodiment represents a molar concentration. For example, at least a portion of the first element M is present in the crystal. A part of the first element M may be present in the composition without being incorporated into the crystal. For example, a part of the first element M may be present in the subphase. In embodiments, the concentration of the first element M in the composition is, for example, greater than 0% and less than or equal to 5%.

Such a radiation detection material provides a radiation detection material and a radiation detection device having a short fluorescence lifetime.

The crystal represented by the above formula (1) is, for example, a scintillator material. In this scintillator material, for example, Ce is the emission center element. The scintillator material has a garnet structure containing Lu, Gd, Ga, Al and O. This makes it easy to match, for example, the peak wavelength of the obtained light irradiated with radiation (for example, γ-rays) to the wavelength at which high sensitivity can be obtained in a detector based on a silicon semiconductor or the like. Light is obtained, for example, by being excited by gamma rays. The peak wavelength of light corresponds to, for example, the peak wavelength of the fluorescent component of fluorescence emission. Detectors based on silicon semiconductors and the like include, for example, PD (Photodiode). The detector includes, for example, Si-PM (Silicon photomultiplier).

The crystals according to the embodiment are, for example, high density. It is preferable that the crystals have a high density because the high density of the crystals increases the probability of interaction with γ-rays. The crystal has a high energy resolution. For example, a garnet-type crystal for a scintillator having a short fluorescence lifetime, high density, high emission amount, and high energy resolution can be obtained. Due to the short fluorescence lifetime, the afterglow of the scintillator can be suppressed. Therefore, for example, in PET (Positron Emission Tomography), a clear image with high spatial resolution can be obtained.

The composition contained in the radiation detection material according to the embodiment is, for example, a fluorescent material. In the above formula (1), the composition ratio of oxygen is about 12. Thus, for example, the crystal has a garnet structure.

In embodiments, the entire crystal does not have to have a complete garnet structure. For example, the crystal may have an oxygen-deficient garnet structure or an oxygen-rich garnet structure. For example, the above-mentioned "x" value and "y" value may cause a state of oxygen deficiency or a state of excess oxygen.

Fluorescent materials containing oxides of garnet structure are radiation stable. Such a fluorescent material has a high emission intensity. The emission of the fluorescent material is generated by the binding of electrons and holes generated by X-ray excitation in the luminescent ions.

The above "z" indicates the amount of Ce. For example, 0 <z ≦ 0.05 is satisfied. When "z" is 0, there is no Ce atom which is a luminescent center element. Therefore, it is difficult to convert the absorbed X-ray energy into light energy. If "z" is greater than 0.05, the distance between Ce atoms becomes too short. For this reason, energy migration (so-called concentration quenching) occurs, and the emission intensity tends to decrease. In the embodiment, for example, it is preferable that 0.0001 ≦ z ≦ 0.04 is satisfied. This makes it easier to obtain, for example, high emission intensity. In the embodiment, it is more preferable that, for example, 0.0005 ≦ z ≦ 0.02 is satisfied. It becomes easier to obtain high emission intensity.

The above "x" indicates the amount of Gd. For example, it is preferable that 0 ≦ x ≦ 0.5 is satisfied. When 0 ≦ x ≦ 0.5, for example, the band gap increases, and the amount of light emitted increases accordingly. It is more preferable that 0 ≦ x ≦ 0.2. This makes it easier to suppress, for example, non-radiative transitions.

Regarding the above "u", it is preferable that 0.3 ≦ u ≦ 0.7. When 0.3 ≦ u ≦ 0.7, for example, the site selectivity of Al and Ga is enhanced, and the crystallinity can be improved. If 0.3 ≦ u ≦ 0.7, for example, Al and Ga may occupy the site in a disorderly manner, causing a decrease in crystallinity. For example, it is more preferable that 0.35 ≦ u ≦ 0.45. When 0.35 ≦ u ≦ 0.45, the crystallinity can be further improved.

Regarding the above "v", it is preferable that -0.1 ≦ v ≦ 0.1. When −0.1 ≦ v ≦ 0.1, the garnet structure is easily formed. If −0.1 ≦ v ≦ 0.1, for example, a subphase having no garnet structure may be generated. For example, it is more preferable that −0.05 ≦ v ≦ 0.05. When −0.05 ≦ v ≦ 0.05, the garnet structure is more easily formed, and the formation of the subphase can be effectively suppressed.

Regarding the above "w", it is preferable that -0.1 ≦ w ≦ 0.1. When −0.1 ≦ w ≦ 0.1, the garnet structure is easily formed. If −0.1 ≦ w ≦ 0.1, a subphase having no garnet structure may be generated. For example, it is more preferable that −0.05 ≦ v ≦ 0.05. When −0.05 ≦ v ≦ 0.05, the garnet structure is more easily formed, and the formation of the subphase can be effectively suppressed.

The above "y" corresponds to the composition ratio of the first element M. The inclusion of the first element M in the crystal suppresses the formation of shallow trap levels due to, for example, oxygen defects. For "y", it is preferable that 0 <y ≦ 0.05. When Ce, which is the luminescence center element, is ionized, the valences of ^{Ce 3+} and Ce ^{4+ are stable.} For that contributes to the scintillator emission is Ce @ 3 ^+, that many of Ce is ^{Ce 3+} is desirable. On the other hand, one of the factors that increase the fluorescence lifetime is the transition from the shallow trap level formed by the oxygen defect to the long fluorescence lifetime. In the presence of the first element M, which is stable in divalent ions, part ^{of Ce 3+} becomes ^{Ce 4+ for charge compensation.} The Ce ⁴⁺ produced suppresses the long fluorescence lifetime transition from shallow trap levels due to oxygen defects. As a result, it is considered that the presence of the first element M shortens the fluorescence lifetime. When 0 <y ≦ 0.05, ^{the concentration of Ce 4+} is appropriately controlled to a value effective for suppressing the transition of long fluorescence lifetime from the shallow trap level. It is more preferable that 0 <y ≦ 0.01. When 0 <y ≦ 0.01, ^{the concentration of Ce 4+} can be easily controlled to an effective value by suppressing the transition of long fluorescence lifetime from the shallow trap level. When 0 <y ≦ 0.05, for example, ^{the concentration of Ce 4+} becomes excessively high, for example, the self-absorption of light emission in the radiation detection material (or crystal) is increased, and the amount of light emission tends to decrease.

The ratio y / z (molar concentration ratio) of the first element M to Ce is preferably 0.1% or more and 50% or less. When y / z is 0.1% or more and 50% or less, for example, ^{the concentration of Ce 4+} with respect to Ce ³⁺ is appropriately controlled to a value effective for suppressing the formation of shallow trap levels. When y / z is less than 0.1%, it becomes difficult to sufficiently suppress the transition of long fluorescence lifetime from the shallow trap level. When y / z exceeds 50%, the concentration of ^{Ce 3+ is insufficient, the concentration of Ce 4+} becomes excessively high, the probability of reaction with γ-rays decreases, and the light emission in the radiation detection material (or crystal) is emitted. It causes an increase in self-absorption, and the amount of light emitted tends to decrease.

The concentration of the first element M contained in the composition is, for example, higher than 0% and 5% or less. The concentration of the first element M contained in the composition is, for example, more preferably higher than 0% and 1% or less.

The composition can be prepared, for example, as follows. As the raw material powder, a ruthenium compound, a cerium compound, an aluminum compound, a gallium compound, and a compound containing the first element M are weighed and mixed so as to have a desired composition. The mixing may be dry or wet. The mixture thus prepared is heat-treated in an air atmosphere at 1300 ° C. or higher and 1700 ° C. or lower. At this time, the temperature conditions are determined so that the decomposition of the raw material and the production of the composition are not insufficient and the produced composition is not decomposed, melted or sublimated. For example, the heat treatment time is preferably 1 hour or more and 30 hours or less. The heat treatment time may be changed according to the temperature conditions.

Hereinafter, an example of the experimental results conducted by the inventor will be described.

The first sample is prepared as follows. Raw material powders include lutetium oxide (Lu ₂ O ₃ ) powder, cerium oxide (CeO ₂ ) powder, aluminum oxide (Al ₂ O ₃ ) powder, gallium oxide (Ga ₂ O ₃ ) powder, and strontium carbonate (SrCO ₃ ). Is prepared. These raw material powders are mixed so as to have a composition of _{(Lu 0.98} Sr _0.01 Ce _0.01 ) ₃ (Al _0.6 Ga _0.4 ) ₅ O _12.

The mixture of raw material powders is heat treated in an air atmosphere at 1450 ° C. for 12 hours. As a result, an oxide having a composition represented _{by (Lu 0.99} Ce _0.01 ) ₃ (Al _0.6 Ga _0.4 ) ₅ O _{12 is obtained.} This oxide has a garnet structure. This oxide is pulverized to obtain the powder of the first sample.

The strontium carbonate in the first sample is _{changed to calcium carbonate (CaCO 3} ), and other than that, the same treatment as in the first sample is performed to obtain the powder of the second sample.

Strontium carbonate in the first sample is _{changed to magnesium carbonate (MgCO 3} ), and other than that, the same treatment as in the first sample is performed to obtain the powder of the third sample.

The fourth sample is obtained as follows. As raw material powders, lutetium oxide (Lu ₂ O ₃ ) powder, cerium oxide (CeO ₂ ) powder, aluminum oxide (Al ₂ O ₃ ) powder, and gallium oxide (Ga ₂ O ₃ ) powder are prepared. These raw material powders are mixed so as to be _{(Lu 0.99} Ce _0.01 ) ₃ (Al _0.6 Ga _0.4 ) ₅ O _12. The mixture of the raw material powders is heat-treated in the same manner as the first sample and pulverized to obtain the powder of the fourth sample.

These samples are melted with alkali and then analyzed by ICP emission spectroscopy. For the analysis, SPS-3520UV manufactured by Hitachi High-Tech Science Co., Ltd. is used. The results of the analysis are:
In the first sample, when the sum of the concentrations of Al and Ga is standardized as 5, the composition ratio of Lu is 3.00, the composition ratio of Ce is 0.03, and the composition ratio of Ga is 2.00. The composition ratio of Al is 3.00, the composition ratio of O is 11.7, and the composition ratio of Sr is 0.001. In the first sample, x = 0, y = 0.00033, z = 0.0099, u = 0.4, v = 0.031, w = 0.3.

In the second sample, when the sum of the concentrations of Al and Ga is standardized as 5, the composition ratio of Lu is 2.98, the composition ratio of Ce is 0.03, and the composition ratio of Ga is 1.98. The composition ratio of Al is 3.02, the composition ratio of O is 11.7, and the composition ratio of Ca is 0.001. In the second sample, x = 0, y = 0.00033, z = 0.01, u = 0.4, v = 0.011, w = 0.3.
In the third sample, when the sum of the concentrations of Al and Ga is standardized as 5, the composition ratio of Lu is 2.97, the composition ratio of Ce is 0.03, and the composition ratio of Ga is 1.96. The composition ratio of Al is 3.04, the composition ratio of O is 11.5, and the composition ratio of Mg is 0.001. In the third sample, x = 0, y = 0.00033, z = 0.01, u = 0.394, v = 0.001, w = 0.5.

In the fourth sample, when the sum of the concentrations of Al and Ga is standardized as 5, the composition ratio of Lu is 3.00, the composition ratio of Ce is 0.03, and the composition ratio of Ga is 1.98. The composition ratio of Al is 3.02, and the composition ratio of O is 11.7. In the fourth sample, x = 0, y = 0, z = 0.01, u = 0.4, v = 0.03, w = 0.3.

FIG. 1 is a graph illustrating the characteristics of a radiation detection material.
FIG. 1 illustrates an X-ray Diffraction (XRD) pattern of the above sample. The horizontal axis of FIG. 1 is an angle of 2θ (°). The vertical axis of FIG. 1 is the intensity Int (arbitrary unit) of the obtained peak. In FIG. 1, in addition to the diffraction patterns of the first to fourth samples SP1 to SP4, the PDF (Powder Diffraction File) pattern of _{"00-044-048 Gd 3} Ga ₂ Al ₃ O _{12" is illustrated.}

As can be seen from FIG. 1, in the first to fourth samples SP1 to SP4, a profile similar to the PDF pattern of " _{00-044-048 Gd 3} Ga ₂ Al ₃ O _{12" is obtained.} From this, it can be seen that the first to fourth samples SP1 to SP4 have a garnet structure.

The following scintillation characteristics are evaluated for the first to fourth samples SP1 to SP4. As the radiation applied to the sample, 667 keV γ-rays generated from ^{a Cs 137 coin source are used.} The amount of light emitted and the fluorescence lifetime when the sample is irradiated with γ-rays are measured. The sample is adhered onto the photomultiplier tube using optical grease. They are placed in a stainless steel case. ^{A Cs 137} coin source is placed on top of the case. The ^{sample is irradiated with γ-rays from a Cs 137} coin source, and the generated light emission is detected by a photomultiplier tube. The resulting signal is amplified by the amplifier. The amount of light emitted is evaluated by the pulse wave height spectrum obtained by a multi-channel analyzer. The fluorescence lifetime is evaluated by the scintillation attenuation curve obtained by a digital oscilloscope.

FIG. 2 is a graph illustrating the characteristics of the radiation detection material.
FIG. 2 shows a pulse wave height spectrum in the first sample SP1 as an example. In FIG. 2, the horizontal axis is the channel value Ch. The vertical axis is the count number Cnt. In FIG. 2, the value of the x-intercept of the wave height spectrum corresponds to the amount of light emitted. Similar evaluations are performed for other samples.

The evaluation results are as follows:
In the first sample SP1, the amount of light emitted (relative value) is 1.00, and the fluorescence lifetime is 53 ns. In the second sample SP2, the amount of light emitted (relative value) is 1.00, and the fluorescence lifetime is 50 ns. In the third sample SP3, the amount of light emitted (relative value) is 0.89, and the fluorescence lifetime is 53 ns. In the fourth sample SP4, the amount of light emitted (relative value) is 1.00, and the fluorescence lifetime is 55 ns.

As described above, in the first to third samples SP1 to SP3, a shorter fluorescence lifetime can be obtained as compared with the fourth sample SP4.

(Second Embodiment)
FIG. 3 is a schematic view illustrating the radiation detection device according to the second embodiment.
As shown in FIG. 3, the radiation detection device 150 according to the second embodiment includes a radiation detection material 110 and a detector 20. The radiation detection material 110 includes the radiation detection material according to the first embodiment and a modification thereof. The detector 20 detects 10 L of light emitted from the radiation detection material 110. The radiation detection material 110 contains the composition 10. The composition 10 contains the above-mentioned crystal 11 and the above-mentioned first element 12.

For example, radiation 80 (for example, γ-rays) is emitted from the inspection target 50. The radiation 80 is incident on the radiation detection material 110, and 10 L of light is emitted. By detecting the light with the detector 20, information about the inspection target 50 can be obtained.

The radiation detector 150 may include, for example, a positron emission tomography system.

The embodiment relates to, for example, a fluorescent material of a garnet-type oxide having a composition containing Gd, Al and Ga. Embodiments relate, for example, to scintillator materials.

The scintillator absorbs radiation such as α-rays, β-rays, γ-rays and X-rays and emits fluorescence. A ray can be detected by combining a scintillator and a photodiode that detects fluorescence. Scintillators are used, for example, in positron emission tomography (PET) devices and medical imaging devices such as X-ray computed tomography (CT devices). Scintillators are used in industrial fields such as non-destructive inspection. Scintillators are used in security areas such as baggage inspection. Scintillators are used in various application fields such as resource exploration fields or academic fields such as high energy physics.

Generally, a radiation detector includes a scintillator and a light receiving element that receives scintillator light and converts it into an electric signal or the like.

For example, in cancer diagnosis by positron emission tomography (PET), a drug containing glucose, which has the property of gathering around cancer cells, and a trace amount of radioisotope is administered to the patient. Gamma rays emitted by the drug are converted into low-energy photons by the scintillator. The photon is converted into an electrical signal by, for example, a photodetector. Photodetectors include, for example, photodiodes (PD), silicon photomultipliers (Si-PM), photomultiplier tubes (PMT), and the like. The electric signal data is processed by a computer or the like to obtain information such as an image, and the location of the cancer is found.

For example, two gamma rays in opposite directions are emitted. For example, in a PET device, a plurality of radiation detectors (including a scintillator and a photodetector) are provided on the circumference. Two position scintillators irradiated with gamma rays emit light, and the photodetector converts the light into an electrical signal. The electrical signal is an image obtained by the electrical circuit and software.

For example, in a radiation detector in high energy physics, a scintillator converts radiation into a plurality of low energy photons, which are converted into electrical signals by a light receiving element.

PD and Si-PM are widely used in radiation detectors and imaging devices. In PD and Si-PM containing a silicon semiconductor, the wavelength having high sensitivity is, for example, 450 nm to 700 nm, and the sensitivity is highest in the vicinity of 600 nm. PD and Si-PM containing a silicon semiconductor are used, for example, in combination with a scintillator having an emission peak wavelength in the vicinity of 600 nm.

For radiation imaging, for example, a combination including a scintillator array and a photodetector array is used. As the photodetector, for example, a position-sensitive PMT is used. As the photodetector, for example, an array of semiconductor photodetectors is used. Arrays of semiconductor photodetectors include, for example, PD arrays, avalanche photodiode arrays (APD arrays), Geiger mode APD arrays, and the like. The photodetector determines which scintillator emitted the light contained in the scintillator array. This makes it possible to know the position of the scintillator array where the radiation is incident.

A scintillator suitable for a radiation detector is required to have a high density and a large atomic number (high photoelectric absorption ratio), for example, from the viewpoint of detection efficiency. A scintillator suitable for a radiation detector is desired to have a large amount of light emission and a short fluorescence lifetime (fluorescence attenuation time), for example, from the viewpoint of the need for high-speed response and high energy resolution. For example, it is desired that the emission wavelength of the scintillator matches the wavelength range in which the detection sensitivity of the photodetector is high.

As a scintillator, for example, there is a scintillator having a garnet structure. A scintillator having a garnet structure is chemically stable, has no cleavage or deliquescent property, and is excellent in workability.

Cerium-doped scintillators are used with photodetectors to detect high-energy photons and particles in a variety of applications, including high-energy physics, medical imaging, geological exploration, or land security. In these scintillators, for example, high scintillation light yield, fast scintillation dynamics (both decay time and rise time), good energy resolution, high proportionality, and / or relatively insensitive to exposure to external light. Is desired.

In order to achieve these demands, it is desired to obtain, for example, an electron / hole trap that may interfere with the scintillation process, or a composition with few (or no) other defects. In scintillators, good thermal response characteristics with good performance over a wide temperature range are desired.

For example, it tends to be difficult to achieve both high optical output and high-speed response. _{For example, LaBr 3} is a material having a relatively high light output and a short fluorescence lifetime predominantly in high-speed response. However, since this material has deliquescent property, it is considered to be insufficient from the viewpoint of practicality. For example, a chemically stable scintillator material having a high light output and a short fluorescence lifetime is desired.

According to the embodiment, a radiation detection material and a radiation detection device having a short fluorescence lifetime can be provided.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, regarding the specific constitution of each element such as the composition part, the crystal, the first element and the detector included in the radiation detection material and the radiation detection device, the present invention can be obtained by appropriately selecting from a range known to those skilled in the art. It is included in the scope of the present invention as long as it can be carried out in the same manner and the same effect can be obtained.

Further, a combination of any two or more elements of each specific example to the extent technically possible is also included in the scope of the present invention as long as the gist of the present invention is included.

In addition, all radiation detection materials and radiation detection devices that can be implemented by those skilled in the art with appropriate design changes based on the radiation detection materials and radiation detection devices described above as embodiments of the present invention also provide the gist of the present invention. As far as it is included, it belongs to the scope of the present invention.

In addition, within the scope of the idea of the present invention, those skilled in the art can come up with various modified examples and modified examples, and it is understood that these modified examples and modified examples also belong to the scope of the present invention. ..

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

10 ... composition, 10L ... light, 11 ... crystal, 12 ... first element, 20 ... detector, 50 ... inspection target, 80 ... radiation, 110 ... radiation detection material, 150 ... radiation detector, Ch ... channel value, Cnt ... Count number, Int ... Intensity, SP1 to SP4 ... 1st to 4th samples

Claims (6)

It comprises a composition containing crystals having a garnet structure.
The crystals contain a first element M containing at least one selected from the group consisting of Ca, Sr, Ba and Mg.
The crystal is
_{(Lu 1-x-y-} z Gd x M y Ce z) 3 + v (Al 1-u Ga u) 5 O 12-w,
0 ≦ x ≦ 0.5,
0 <y ≤ 0.05,
0 <z ≤ 0.05,
0.3 ≤ u ≤ 0.7,
-0.1 ≤ v ≤ 0.1,
-0.1 ≤ w ≤ 0.1,
A radiation detection material having the composition of. The radiation detection material according to claim 1, wherein the ratio y / z is 0.1% or more and 50% or less. The radiation detection material according to claim 1 or 2, wherein the concentration of the first element M contained in the composition is higher than 0% and 5% or less. The radiation detection material according to any one of claims 1 to 3, wherein y is 0 <y ≦ 0.01. The radiation detection material according to any one of claims 1 to 4, wherein z is 0.0001 ≦ z ≦ 0.04. The radiation detection material according to any one of claims 1 to 5,
A detector that detects the light emitted from the radiation detection material, and
Radiation detector equipped with.

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