JP2002062359A - Radiation-measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a radiation-measuring apparatus, for detecting γ-rays to measure in a low energy region by reducing cutting energy. SOLUTION: Output pulses from a radiation detector 20 and a plurality of radiation detectors 22 are bound and are counted at an OR circuit 24. The radiation detectors 22 detect charges generated by radioactive rays in a radiation detection semiconductor element 42, without being converted to a light at a scintillator, while conversion into the light at the scintillator is interposed in the radiation detector 20. A lower cut level can be set to the radiation detectors 22 than to the radiation detector 20 because of this difference of methods of detecting the radioactive rays. The measuring apparatus has a measuring range extended towards the low energy side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation measuring device for measuring a radiation dose, and more particularly to a radiation measuring device in which the measurable energy is extended to a lower energy side.

[0002]

2. Description of the Related Art FIG. 10 is a schematic block diagram of a conventional radiation measuring apparatus. This radiation measuring device is CsI
The scintillator 2 made using (Tl) emits light due to incident radiation, and this light is detected by the photodiode 4. The photodiode 4 generates a charge according to the amount of incident light. This charge amount is converted into a voltage corresponding to the capacitance of the photodiode. The voltage signal is amplified by the amplifier 6, and the discriminator 8 generates a pulse when the amplified voltage signal exceeds a predetermined threshold. Counting circuit 10
Counts the pulses, converts them into desired measurement values such as a dose rate, and displays the result on the display 12.

For example, a scintillator 2 has a size of 10 × 10 × 1.
0mm, one surface of which has a sensitive area of 10mm
Corner (hereinafter referred to as 10 mm square), that is, 100 m
m ² photodiodes 4 are arranged. The noise level of a photodiode depends on its area. That is,
The capacitance of a photodiode is proportional to the area, and thus the signal voltage is basically inversely proportional to the area. And, the larger the area, the lower the signal voltage level, and the more likely it is to be affected by noise.

When radiation is incident on a 10 mm square photodiode 4 to cause ionization, for example, 15 k
An eV cut energy is obtained. Here, it means that the voltage signal generated when the radiation of 15 keV is incident on the photodiode 4 is a limit that can be discriminated from the noise level. On the other hand, when radiation is incident on the scintillator 2 and converted into scintillation light, and this light is detected by the same photodiode 4, for example, 100 ke
V cut energy is obtained. This is 100ke
For example, when a gamma ray of V is incident on the scintillator 2,
The amount of charge generated in the photodiode 4 due to the scintillation light and the 15 ke
This means that the amount of charge generated when V radiation is incident is equivalent. As described above, the noise level when the photodiode 4 is used as an optical sensor is reduced 7 to 8 times as compared with that when the photodiode 4 is used as a radiation detecting element.

FIG. 11 is a graph schematically showing sensitivity characteristics of a conventional radiation detector including a scintillator and a photodiode. In the figure, the horizontal axis represents the energy E of the incident γ-ray, and the vertical axis represents the γ-ray emitted by ¹³⁷ Cs (E = 6
The response R is based on 62 keV), and the energy dependence curve 16 of the response is shown. As described above, in this detector, γ at about E = 100 keV
The electric signal of the photodiode corresponding to the line is on the order of the noise level. Therefore, those signals are removed together with the noise, and the response sharply decreases when approaching E = 100 keV.

On the other hand, the reason why an electric signal is generated in response to radiation incident on the photodiode 4 is, for example, a thickness of 300
In contrast to a very thin depletion layer such as μm, the scintillator 2 provides a large passage distance for radiation. Therefore, when the scintillator 2 is arranged in front of the photodiode 4 and the photodiode 4 is used as an optical sensor,
Greater sensitivity is obtained than when the photodiode 4 alone is used as a radiation detecting element.

[0007]

As described above, the conventional radiation measuring apparatus in which light emitted from the scintillator is detected by the photodiode has a problem that the cut energy is large. On the other hand, a conventional configuration in which ionization due to radiation is detected by an element such as a photodiode formed on a semiconductor substrate has a problem of low sensitivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a radiation measuring apparatus in which cut energy is improved while maintaining sensitivity characteristics.

[0009]

A radiation measuring apparatus according to the present invention includes a scintillator emitting light by radiation and a semiconductor element for detecting the light emission, and a first sensitivity characteristic for detecting radiation having a first energy or more. The first with
A radiation detector, including a radiation detection semiconductor element for detecting ionization due to radiation, a plurality of second radiation detectors for detecting radiation of a second energy or more lower than the first energy, and A counting unit that counts the radiation based on the radiation detection signal of the radiation detection signal from each of the plurality of second radiation detectors,
The plurality of second radiation detectors have a second sensitivity characteristic corresponding to the first sensitivity characteristic between the second energy and the first energy as a combined sensitivity characteristic.

According to the present invention, the first radiation detector detects radiation by emitting light from the scintillator. The light emission detecting semiconductor element is constituted by, for example, a photodiode formed on a semiconductor substrate. When light from a scintillator enters a charge depletion layer when reverse bias is applied, the light is converted into charges. As a result, an electric pulse corresponding to the incidence of radiation is output as a radiation detection signal. On the other hand, the second radiation detector generates an electric pulse by the ionization effect of the radiation in the radiation detecting semiconductor element, and outputs the electric pulse as a radiation detection signal. The radiation detecting semiconductor element can be basically configured by an element similar to the photodiode of the emission detecting semiconductor element. Here, unlike the first radiation detector, the second radiation detector directly converts radiation into electric charge without conversion into light. Due to the difference in the mechanism of conversion to electric charge,
For example, if the semiconductor elements for light emission detection or radiation detection of both radiation detectors have the same sensitive area, the noise level of the second radiation detector will be lower than that of the first radiation detector. In this way, the second radiation detector can set the cut level to the second energy lower than the first radiation detector, and can detect radiation having lower energy than the first radiation detector. On the other hand, the first radiation detector converts light into light with a scintillator having a relatively large volume, whereas the second radiation detector detects radiation with an extremely thin charge depletion layer. Is lower than the first sensitivity characteristic of the first radiation detector. Therefore, in the present invention, a plurality of second radiation detectors are provided, and in particular, the sensitivity characteristics from the second energy to the first energy that are not covered by the first radiation detector are improved. That is, by arranging a plurality of second radiation detectors, the sensitivity increases in accordance with the number of each second radiation detector. Incidentally, the number of the second radiation detectors provided between the second energy and the first energy is such that a desired level of the second sensitivity characteristic is achieved. The second sensitivity characteristic is set in accordance with the first sensitivity characteristic, so that effective radiation measurement can be performed in a low energy range from the second energy to the first energy in the same manner as in the energy range above the first energy.

A radiation measuring apparatus according to the present invention includes a first scintillator emitting light by radiation and a first semiconductor element detecting light emission from the first scintillator, and a first sensitivity characteristic for detecting radiation having a first energy or more. A first radiation detector having: a second scintillator emitting light by radiation; and a second scintillator detecting light emission by the second scintillator.
A second radiation detector including a semiconductor element and detecting radiation having a second energy or more lower than the first energy;
A radiation detection signal from the first radiation detector and the second radiation detection signal;
A counting unit for counting radiation based on a radiation detection signal from a radiation detector, wherein the sensitive surface of the second semiconductor element for the light emission is more sensitive than the sensitive surface of the first semiconductor element for the light emission. The second radiation detector is configured to be small, and has a second sensitivity characteristic corresponding to the first sensitivity characteristic between the second energy and the first energy.

According to the present invention, each of the first radiation detector and the second radiation detector detects radiation by emission of radiation from the scintillator. Since the sensitive surface of the second semiconductor element for light emission in the scintillator is smaller than that of the first semiconductor element and therefore has a smaller capacitance, the second energy which is the cut level of the second radiation detector is equal to the first radiation detector. The cut level of the first
It can be set smaller than the energy. The sensitivity of the second radiation detector is determined according to the volume of the second scintillator. The second sensitivity characteristic between the second energy and the first energy is set according to the first sensitivity characteristic,
In the low energy range from energy to the first energy, effective radiation measurement can be performed in the same manner as in the energy range above the first energy.

[0013] A radiation measuring apparatus according to the present invention includes a first scintillator emitting light by radiation and a first semiconductor element detecting light emission from the first scintillator, and a first sensitivity characteristic detecting radiation having a first energy or more. A first radiation detector having: a second scintillator that emits light by radiation; and a second semiconductor element that detects both light emitted by the second scintillator and radiation that has passed through the second scintillator. A second radiation detector that detects radiation having a low second energy or more, and a counting unit that counts radiation based on a radiation detection signal from the first radiation detector and a radiation detection signal from the second radiation detector. And the second scintillator has a thickness that partially allows the incident radiation to pass therethrough, and the second radiation detector Has a second sensitivity characteristic commensurate with the first sensitivity characteristic in between the second energy to the first energy.

According to the present invention, each of the first radiation detector and the second radiation detector detects radiation by emission of radiation from the scintillator. The second scintillator is configured to be thinner than the first scintillator, so that a part of the incident radiation is converted to light, while the other part is transmitted without being converted to light. That is, basically, the light generated by the scintillator and the transmitted radiation are incident on the second semiconductor element, and both of them are detected. The second radiation detector has, as a cut level, a second energy lower than the first energy which is the cut level of the first radiation detector by detecting the passed radiation. On the other hand, by detecting the light of the second scintillator, the sensitivity of the second radiation detector is improved as compared with the case where all of the radiation enters the semiconductor element and causes ionization. The provision of the second radiation detector enables measurement at a first energy or lower that cannot be measured by the first radiation detector. The second sensitivity characteristic between the second energy and the first energy is set according to the first sensitivity characteristic. The second sensitivity characteristic is adjusted by the thickness of the second scintillator, so that effective radiation measurement can be performed in the low energy range from the second energy to the first energy, as well as in the energy range above the first energy.

A radiation measuring apparatus according to the present invention is provided with a scintillator which emits light by radiation, a plurality of semiconductor elements which are divided and arranged on an emission end face of the light emission of the scintillator, and which detect the light emission, and a plurality of the semiconductor elements. A plurality of detection signal generation units that respectively generate radiation detection signals based on the outputs of the semiconductor elements; and a counting unit that counts radiation based on the radiation detection signals.

According to the present invention, the light-emitting end face of the scintillator is divided into a plurality of regions, and a semiconductor element and a detection signal generator are assigned to each region. That is, instead of detecting light from the emission end face with one semiconductor element, the light is detected using a plurality of smaller semiconductor elements.
In this configuration, since the area of each semiconductor element is reduced,
The cut level of the detection signal generation unit is lower than when one semiconductor element is assigned to the emission end face. The total effective area is basically the same as the case where one semiconductor element is provided. That is, the radiation count value obtained by the counting unit is the same as when one semiconductor element is provided,
The sensitivity characteristic is maintained at the same level as one semiconductor element.

[0017]

Next, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1] FIG. 1 is a schematic block diagram of a radiation measuring apparatus according to a first embodiment of the present invention. This radiation measuring device includes a radiation detector 20 for detecting scintillation light and a radiation detector 22 for detecting ionization due to radiation, and measures a dose equivalent rate of γ-rays. A plurality of radiation detectors 22 are provided, and pulses from each of the radiation detector 20 and each radiation detector 22 generated by the radiation detection are input to an OR circuit 24. O
The R circuit 24 combines outputs from the radiation detectors into one and inputs the combined output to the counting circuit 26. The counting circuit 26 counts the pulses output from each radiation detector per unit time, converts it into a dose equivalent rate, and displays the result on the display 2.
8 is displayed.

The radiation detector 20 includes a scintillator 30,
It is configured to include a photodiode 32, an amplifier 34, and a discriminator 36. On the other hand, the radiation detector 22
Is configured to include a semiconductor element for radiation detection 42, an amplifier 34, and a discriminator 36. FIG. 1 shows an example in which the number of radiation detectors 22 is four for convenience, but the number is specifically determined according to a desired sensitivity characteristic as described later.

The scintillator 30 is, for example, CsI (T
1) and has a size of 10 × 10 × 10 mm. The scintillator 30 emits light due to incident radiation. One surface of the scintillator 30 is in contact with the photodiode 32, and the other surface is covered with a reflective film. Thereby, the light generated in the scintillator 30 is
The light enters the photodiode 32 directly or after being reflected by the reflection film.

The photodiode 32 is a semiconductor element formed by diffusing impurities on a semiconductor substrate, and detects light from the scintillator 30. Specifically, the photodiode 32 is reverse biased by the power source V _B, the charge depletion layer is formed. When light enters the depletion layer, charges corresponding to the amount of light are generated. For example,
The sensitive area of the photodiode 32 is the scintillator 30
10mm □ (10 × 10mm) according to the light emitting end face of
It is composed of

On the other hand, the radiation detecting semiconductor element 42 is also a semiconductor element formed by diffusing impurities on a semiconductor substrate, and has basically the same structure as that of the photodiode 32. The resulting charge is taken out as a signal. Since the structure is similar to that of the photodiode 32, when light enters the depletion layer, charges are generated. Therefore, the sensitive surface of the radiation detecting semiconductor element 42 is shielded from light. Here, the sensitive area is configured to be 10 mm square as with the photodiode 32.

Each of the charges generated in the photodiode 32 and the radiation detecting semiconductor element 42 is converted into a voltage signal corresponding to their capacitance. This voltage signal is amplified by the amplifier 34. The amplification unit 34 includes a charge detection preamplifier and a main amplifier.

The discriminator 36 generates a pulse when the amplified voltage signal exceeds a predetermined threshold. This threshold value is determined by the photodiode 32 and the radiation detecting semiconductor element 4.
The value is set to a value exceeding the noise level of 2, and the discriminator 36 eliminates counting due to noise.

Here, the photodiode 32 and the radiation detecting semiconductor element 42 can be the same semiconductor element. In this case, the threshold value of each discriminator 36 of the radiation detectors 20 and 22 is common to the electric pulse. Can be set to the value of However, also in this case, the cut level set for the incident radiation by the discriminator 36 due to the difference in the conversion efficiency from the energy of the incident radiation to the electric charge between the radiation detector 20 and the radiation detector 22. Are different from each other. Therefore, for example, even if the discriminator 36 has an electrically common threshold value, the radiation detector 20 sets the cut level to 100 keV, and the radiation detector 22 sets the cut level to 15 keV.
It will be set to a considerable cut level.

FIG. 2 is a schematic graph showing the energy dependence of the response of the present apparatus. In the figure, the horizontal axis represents the energy E of the incident γ-ray, and the vertical axis represents the response R based on the γ-ray (E = 662 keV) emitted by ¹³⁷ Cs. The energy dependence curve 50 of the response of the present apparatus is a superposition of the response curve 52 of the radiation detector 20 and the response curve 54 of the radiation detector 22 group. Note that the response curve 56 is
The respective response curves are superimposed on all of the plurality of radiation detectors 22 to form a response curve 54.

Due to the discriminator 36, the response curve 52 of the radiation detector 20 is set to 100 k as described above.
has a cut level equivalent to eV, while the radiation detector 2
The response curve 54 of FIG. 2 has a cut level equivalent to 15 keV as described above.

The radiation detector 22 alone can obtain a lower response than the radiation detector 20 alone. Therefore, in the present apparatus, by providing a plurality of radiation detectors 22, the response in the low energy region below the cut level of the radiation detector 20 is increased. That is, the number of radiation detectors 22 is determined so that the response in the low energy region reaches a desired level. For example, in order to enable effective measurement by the present apparatus over the middle and high energy regions covered by the radiation detector 20 and the low energy region covered by the radiation detector 22, the response characteristics in these entire energy ranges are set. Is achieved. In this case, the number of the radiation detectors 22 is set such that the response in the low energy region is about the response in the middle and high energy region.

[Embodiment 2] FIG. 3 is a schematic block diagram of a radiation measuring apparatus according to a second embodiment of the present invention. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description is simplified.

This radiation measuring apparatus includes a radiation detector 20 and a radiation detector 60 for detecting scintillation light, respectively, and measures the dose equivalent rate of γ-rays. Radiation detector 20 and radiation detector 60 generated by radiation detection
Are combined into one system signal by the OR circuit 24. The counting circuit 26 counts the pulses, and the measured dose equivalent rate is displayed on the display 28.

The basic configuration of the radiation detector 60 is the same as that of the radiation detector 20, and includes a scintillator 62, a photodiode 64, an amplifier 34, and a discriminator 36.
It is comprised including. The radiation detector 60 is significantly different from the radiation detector 20 in that the photodiode 64 is smaller than the photodiode 32, and that the size of the scintillator 62 is also different from that of the scintillator 30. For example, the sensitive surface of the photodiode 64 is 3 m
m □ (3 × 3 mm). Also scintillator 6
2 is configured to have a size of, for example, 10 × 3 × 3 mm in accordance with the light emitting end face of the photodiode 64. The material of the scintillator 62 and the structure of the photodiode 64 are the same as the scintillator 30 and the photodiode 32, respectively.
Can be the same as

Here, the photodiode 64 has a smaller capacitance than the photodiode 32 due to the difference in the sensitive area. Therefore, when the charge amount stored in the photodiode is the same, a voltage signal generated in the photodiode 64 is larger than that in the photodiode 32. Therefore, the cut level in the radiation detector 60 can be set smaller than the cut level in the radiation detector 20. For example, radiation detector 2
The discriminator 36 of 0 is set so that a cut level is generated at 100 keV of the energy of the incident radiation, and the discriminator 36 of the radiation detector 60 is set such that a cut level is generated at 50 keV of the energy of the incident radiation. You.

FIG. 4 is a schematic graph showing the energy dependence of the response of the present apparatus. The vertical and horizontal axes in FIG. 4 are the same as in FIG. The energy dependence curve 70 of the response of this apparatus is the response curve 5 of the radiation detector 20.
2 and the response curve 72 of the radiation detector 60.

The response curve 52 of the radiation detector 20 is set to 100 k by the discriminator 36 as described above.
It has a cut level of eV, while the response curve 72 of the radiation detector 60 has a cut level of 50 keV as described above.

The response curve 72 of the radiation detector 60 rises and falls according to the volume of the scintillator 62. That is,
When the volume of the scintillator 62 is large, the response increases. Therefore, by adjusting the volume of the scintillator 62, it is possible to set the response in the low energy region below the cut level of the radiation detector 20 to a desired level. Thus, the present apparatus is configured such that, for example, the response in the middle and high energy region covered by the radiation detector 20 and the response in the low energy region covered by the radiation detector 60 are at the same level.

[Third Embodiment] FIG. 5 is a schematic block diagram of a radiation measuring apparatus according to a third embodiment of the present invention. In the following description, the same components as those in the first or second embodiment are denoted by the same reference numerals, and the description is simplified.

This radiation measuring device includes a radiation detector 20 and a radiation detector 80 for detecting scintillation light, respectively, and measures the dose equivalent rate of γ-rays. Radiation detector 20 and radiation detector 80 generated by radiation detection
Are combined into one system signal by the OR circuit 24. The counting circuit 26 counts the pulses, and the measured dose equivalent rate is displayed on the display 28.

The basic configuration of the radiation detector 80 is the same as that of the radiation detector 20, and includes a scintillator 82, a photodiode 32, an amplifier 34, and a discriminator 36.
It is comprised including. The radiation detector 80 is significantly different from the radiation detector 20 in that the scintillator 82 is configured to be thinner than the scintillator 30. The thickness of the scintillator 82 is determined such that a part of the incident radiation is converted into light, and the rest passes through the scintillator 82 without being converted into light. The scintillator 82 is, for example, 10
It has a size of × 10 × 1 mm, that is, a thickness of 1 mm. Note that the scintillator 82 can be made of the same material as the scintillator 30.

The photodiode 32 of the radiation detector 80
, The light generated by the scintillator 82 and the radiation that has passed through the scintillator 82 are incident, and both of them are detected. By detecting the radiation that has passed through the scintillator 82, the cut level in the radiation detector 80 can be set smaller than the cut level in the radiation detector 20. As in the first embodiment, even if the discriminators 36 of the radiation detectors 20 and 80 are electrically set to the same threshold, the radiation detector 20 has a cut level equivalent to 100 keV, At 80, it is set to have a cut level equivalent to 50 keV.

On the other hand, by detecting the scintillation light with the scintillator 82, the response of the radiation detector 80 is improved as compared with the case where the radiation detector 22 is used alone.

FIG. 6 is a schematic graph showing the energy dependence of the response of the present apparatus. The vertical and horizontal axes in FIG. 6 are the same as in FIG. The energy dependence curve 90 of the response of this apparatus is the response curve 5 of the radiation detector 20.
2 and the response curve 92 of the radiation detector 80.

The response curve 52 of the radiation detector 20 is set to 100 k by the discriminator 36 as described above.
It has a cut level of eV, while the response curve 92 of the radiation detector 80 has a cut level of 50 keV as described above.

Incidentally, the response curve of the radiation detector 80 varies depending on the thickness of the scintillator 82. That is, as the thickness approaches 0, the response curve 56 of the radiation detector 22 according to the first embodiment approaches the single response curve, and a smaller cut level can be set, while the response decreases. Conversely, as the thickness approaches 10 mm, the response curve 52 of the radiation detector 20 approaches, and the cut level that can be set increases, but the response increases. Therefore,
The thickness of the scintillator 82 is selected in consideration of required cut energy and required response characteristics in a low energy region.

[Embodiment 4] Next, a radiation measuring apparatus according to a fourth embodiment of the present invention will be described. This radiation measuring device converts gamma rays into light using a scintillator, counts the light, and measures the dose equivalent rate. In the following description, the same components as those in the first to third embodiments are denoted by the same reference numerals, and the description is simplified.

FIG. 7 is a schematic perspective view of a sensor part of the radiation measuring apparatus. The sensor unit 100 includes a scintillator and a photodiode. The photodiodes 102 are 3 mm square in size, and nine of them are arranged on the light emitting end face of the scintillator 104 in an array of 3 rows and 3 columns. Similarly to the photodiode 102, nine scintillators 104 are arranged in an array of three rows and three columns, and each is associated with the photodiode 102. Each scintillator 104 has a size of 10 × 3 × 3 mm, and 3
The output end face of 3 mm is brought into contact with the sensitive surface of the photodiode 102. Note that the scintillator may be integrated with the nine photodiodes 102.

FIG. 8 is a schematic block diagram of the radiation measuring apparatus. Each photodiode 10 of the sensor unit 100
An amplifying unit 34 and a discriminator 36 are provided for the outputs obtained from the two. Output pulses from each discriminator 36 are combined into one system signal by the OR circuit 24. The counting circuit 26 counts the pulses, and the measured dose equivalent rate is displayed on the display 28.

In the present apparatus, the cut energy set by each discriminator 36 can be reduced by making the sensitive surface of the photodiode 102 small. By providing a plurality of photodiodes 102, since the sensitive area of each photodiode 102 is small, the point of insufficient sensitivity is compensated for and the required sensitivity can be secured. For example, as compared with the radiation detectors 20 and 60 of the second embodiment, the sensitive area of the photodiode 102 is the same as the photodiode 64 of the radiation detector 60. Therefore, the cut level of this apparatus is lower than 100 keV of the radiation detector 20, for example, 50
It can be set to keV. On the other hand, the sum of the sensitive areas of the nine photodiodes 102 is about the same as the sensitive area of the photodiode 32 of the radiation detector 20, and the total volume of the nine scintillators 104 is also substantially equal to the radiation detector 20. Is about the volume of the scintillator 30. Therefore, the present apparatus can obtain the sensitivity of the radiation detector 20 or so.

FIG. 9 is a schematic graph showing the energy dependence of the response of the present apparatus. The vertical and horizontal axes in FIG. 9 are the same as in FIG. The energy dependence curve 110 of the response of this apparatus is obtained by multiplying the response curve 72 of the radiation detector 60 by 9 in the vertical axis direction.

[0049]

According to the radiation measuring apparatus of the present invention, the cut energy can be reduced while maintaining the sensitivity characteristics.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a radiation measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic graph showing the energy dependence of the response of the radiation measuring device according to the first embodiment of the present invention.

FIG. 3 is a schematic block diagram of a radiation measuring apparatus according to a second embodiment of the present invention.

FIG. 4 is a schematic graph showing the energy dependence of the response of the radiation measuring device according to the second embodiment of the present invention.

FIG. 5 is a schematic block diagram of a radiation measuring apparatus according to a third embodiment of the present invention.

FIG. 6 is a schematic graph showing the energy dependence of the response of the radiation measuring apparatus according to the third embodiment of the present invention.

FIG. 7 is a schematic perspective view of a sensor part of a radiation measuring apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a schematic block diagram of a radiation measuring apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a schematic graph showing the energy dependence of the response of the radiation measuring apparatus according to the fourth embodiment of the present invention.

FIG. 10 is a schematic block diagram of a conventional radiation measurement device.

FIG. 11 is a schematic graph showing an energy dependence characteristic of a response of a conventional radiation detector.

[Explanation of symbols]

20, 22, 60, 80 Radiation detector, 24 OR circuit, 26 counting circuit, 28 display, 30, 62, 8
2,104 scintillator, 32,64,102 photodiode, 34 amplifying unit, 36 discriminator.

Continued on the front page (72) Inventor Shohei Matsubara 6-22-1, Mure, Mitaka City, Tokyo Aloka Co., Ltd. (72) Inventor Naoki Tateishi 6-22-1, Mure, Mitaka City, Tokyo Aloka Co., Ltd. F-term (Reference) 2G088 FF04 GG19 GG21 JJ01 KK06 KK11 KK29 LL05 LL15

Claims (4)

[Claims] A first scintillator that emits light due to radiation and a light-emitting detection semiconductor element that detects the light emission;
A first radiation detector having a first sensitivity characteristic of detecting radiation of energy or more, a plurality of radiation detectors including a radiation detecting semiconductor element for detecting ionization due to radiation, and detecting radiation of second energy or more lower than the first energy A second radiation detector, and a counting unit that counts radiation based on radiation detection signals from the first radiation detector and radiation detection signals from each of the plurality of second radiation detectors, The plurality of second radiation detectors have a second sensitivity characteristic corresponding to the first sensitivity characteristic between the second energy and the first energy as a sensitivity characteristic obtained by combining them. Radiation measurement device. 2. A first radiation detection device including a first scintillator that emits light by radiation and a first semiconductor element that detects light emission from the first scintillator, and has a first sensitivity characteristic of detecting radiation having a first energy or more. A second scintillator that emits light by radiation, and a second semiconductor element that detects light emission from the second scintillator;
A second radiation detector that detects radiation having a second energy or more lower than the first energy, a radiation detection signal from the first radiation detector and the second radiation detector,
A counting unit that counts radiation based on a radiation detection signal from a radiation detector, wherein the sensitive surface of the second semiconductor device for the light emission is a sensitive surface of the first semiconductor device for the light emission. The second radiation detector is configured to have a second sensitivity characteristic corresponding to the first sensitivity characteristic between the second energy and the first energy. . 3. A first radiation detector including a first scintillator emitting light by radiation and a first semiconductor element detecting light emission from the first scintillator, and having a first sensitivity characteristic for detecting radiation having a first energy or more. A second scintillator that emits light by radiation, and a second semiconductor element that detects both light emission from the second scintillator and radiation that has passed through the second scintillator, and a second energy lower than the first energy or more. A second radiation detector that detects the radiation of the first radiation detector, a radiation detection signal from the first radiation detector, and the second radiation detector.
A counting unit that counts radiation based on a radiation detection signal from a radiation detector, wherein the second scintillator has a thickness that partially allows the incident radiation to pass therethrough, and the second radiation The detector according to claim 1, wherein the detector has a second sensitivity characteristic corresponding to the first sensitivity characteristic between the second energy and the first energy. 4. A scintillator that emits light by radiation; a plurality of semiconductor elements that are divided and arranged on the emission end face of the light emission of the scintillator to detect the light emission; A radiation measurement device, comprising: a plurality of detection signal generation units each generating a radiation detection signal based on an output of an element; and a counting unit counting radiation based on each of the radiation detection signals.