Radiation source member, radioactivity measurement device, and efficiency calibration method

Abstract

To provide a radiation source member capable of reducing complicated labor necessary for device calibration and a cost increase, a radioactivity measurement device, and an efficiency calibration method.SOLUTION: The radioactivity measurement device comprises: a radiation source member 10 fitted to a radiation source S; a radiation detector; and a processing unit. The radiation source member 10 includes an attenuation part 10a that attenuates a part of radiation emitted from the radiation source S, and a transmission part 10b that transmits the radiation emitted from the radiation source S without attenuation of other than the part. The processing unit acquires, on the basis of wave-height distribution data obtained by a wave-height value of a pulse signal output from the radiation detector, counting efficiency of the radiation of the radiation detector with respect to the radiation source S or a combination of the radiation source S and the radiation source member 10. The processing unit acquires data of correlation between the amount of the radiation source S associated with at least one attenuation rate acquired by one or a plurality of different radiation source members 10 and the counting efficiency.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a radiation source member, a radioactivity measuring device, and an efficiency calibration method. [Background technology]

[0002] Conventionally, for example, in the efficiency calibration of an apparatus using a standard volume radiation source or the like in which the self-absorption of radiation is taken into consideration, it has become necessary to perform measurements using a plurality of radiation sources for the same nuclide with different self-absorption depending on the volume, weight, etc. For example, when efficiency calibration is performed on a beta ray measurement apparatus using a radioactive strontium carbonate precipitate sample, a method of measuring the efficiency for a plurality of samples of different weights is known (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Radioactivity Measurement Method Series 2: Radioactive Strontium Analysis Method", Japan Chemical Analysis Center, 2003, pp.81-85 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when multiple radiation sources of the same nuclide but with different self-absorption depending on the volume, weight, etc. are used for the efficiency calibration of the device, problems arise in that it requires complicated work to prepare and manage the multiple different radiation sources, and costs increase.

[0005] An object of the present invention is to provide a radiation source component, a radioactivity measuring device, and an efficiency calibration method that can suppress the cumbersome work and increased costs required for calibrating the device. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1): A radiation source member (10) according to one aspect of the present invention includes an attenuation section (10a) that attenuates a portion of the radiation emitted from a radiation source (S), and a transmission section (10b) that transmits the remaining portion of the radiation without attenuating it, and sets the attenuation rate of the radiation within a predetermined range.

[0007] (2): In the radiation source component described in (1) above, the predetermined range may be a range in which the count rate of the radiation detected by the radiation detector attenuates between a reference count rate in a reference state in which there is no self-absorption of the radiation by the radiation source and a count rate that is half the reference count rate.

[0008] (3) In the radiation source member described in (1) or (2) above, the transmitting portion may have voids or pores.

[0009] (4) In the radiation source member described in (3) above, the gaps or pores may be formed along the radiation emission direction.

[0010] (5) In the radiation source member described in (1) or (2) above, the transmitting portion may be formed to have a thickness that is relatively smaller than the thickness of the attenuating portion.

[0011] (6) In the radiation source member described in (5) above, the thickness of the transmitting portion and the thickness of the attenuating portion may be measured along the direction in which the radiation is emitted.

[0012] (7) In the radiation source member described in (1) above, the transmitting portion may be formed in a mesh pattern.

[0013] (8): A radioactivity measuring device (30) according to one aspect of the present invention includes one or more different radiation source components (10) according to (1) or (2) above, a radiation source (S) to which the radiation source component is attached, a radiation detector (31) that outputs a pulse signal corresponding to the energy of the radiation emitted from the radiation source or the energy of the radiation emitted from the radiation source and passed through the radiation source component, a processing unit (33) that generates pulse-height distribution data having counts associated with each of a plurality of channels based on pulse-height values ​​of the pulse signal, and a calculation unit (35) that acquires, based on the pulse-height distribution data, a counting efficiency of the radiation by the radiation detector for the radiation source or a combination of the radiation source and the radiation source component, and the calculation unit acquires data on the correspondence relationship between the amount of the radiation source associated with at least one attenuation rate obtained by the one or more different radiation source components and the counting efficiency.

[0014] (9): An efficiency calibration method according to one aspect of the present invention is a method for calibrating the efficiency of a radioactivity measuring device (30) including: one or more different radiation source components (10) according to (1) or (2) above; a radiation source (S) to which the radiation source components are attached; a radiation detector (31) that outputs a pulse signal corresponding to the energy of the radiation emitted from the radiation source or the radiation emitted from the radiation source and passed through the radiation source component; a processing unit (33) that generates pulse-height distribution data having counts associated with each of a plurality of channels based on pulse-height values ​​of the pulse signal; and a calculation unit (35) that acquires, based on the pulse-height distribution data, a counting efficiency of the radiation by the radiation detector for the radiation source or for a combination of the radiation source and the radiation source component, the counting efficiency being determined by the calculation unit, the calculation unit acquiring data on a correspondence relationship between the counting efficiency and an amount of the radiation source associated with at least one attenuation rate obtained by the one or more different radiation source components. [Effects of the Invention]

[0015] According to the above (1), a desired attenuation rate can be ensured by the radiation passing through the attenuation section, and information on the energy emitted from the radiation source can be retained by the radiation passing through the transmission section. By combining the radiation source with the radiation source member, it is possible to easily simulate multiple radiation sources with different radiation attenuation rates.

[0016] In the case of (2) above, the range of the radiation attenuation rate is set to a predetermined range in which the radiation attenuates between the reference count rate and a count rate that is half the reference count rate, thereby ensuring the desired accuracy when simulating multiple radiation sources.

[0017] In the case of (3) or (4) above, the radiation passing through the gaps or pores can accurately retain information about the energy emitted from the radiation source. In any of the above cases (5) to (7), the attenuation portion and the transmission portion can be easily formed.

[0018] According to the above (8) or (9), the calibration points for efficiency calibration can be easily increased without requiring a plurality of different radiation sources, and the accuracy and reliability of the efficiency calibration of the radioactivity measuring device can be improved while suppressing an increase in cumbersome work and costs. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a perspective view showing a radiation source member and a radiation source according to an embodiment of the present invention, with a portion cut away; [Figure 2] FIG. 2 is a diagram showing an example of a measurement state by a radiation detector according to an embodiment of the present invention. [Figure 3] FIG. 1 is a block diagram showing the functional configuration of a radioactivity measuring device according to an embodiment of the present invention. [Figure 4] 10A and 10B are diagrams showing examples of beta-ray energy spectra obtained by radioactivity measuring devices according to an embodiment of the present invention and a comparative example. [Figure 5] FIG. 2 is a diagram showing an example of the correspondence relationship between the counting efficiency obtained by the radioactivity measuring device according to the embodiment of the present invention and the sample mass and mesh density. [Figure 6] FIG. 2 is a diagram showing an example of the correspondence relationship between the counting efficiency obtained by the radioactivity measuring device according to the embodiment of the present invention and the weight of strontium carbonate precipitate. [Figure 7] FIG. 10 is a partially cutaway perspective view of a radiation source member and a radiation source according to a first modified example of the embodiment of the present invention. [Figure 8] FIG. 10 is a partially cutaway perspective view of a radiation source member and a radiation source according to a second modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] A radiation source member and a radioactivity measuring device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. The radioactivity measuring device according to the embodiment measures the radioactivity of a radiation source that emits radiation such as gamma rays, X-rays, beta rays, alpha rays, and neutron rays. Fig. 1 is a perspective view showing a radiation source member 10 and a radiation source S according to an embodiment, with a part cut away. Fig. 2 is a diagram showing an example of a measurement state by a radiation detector 31 according to an embodiment. Fig. 3 is a block diagram showing the functional configuration of a radioactivity measuring device 30 according to an embodiment.

[0021] As shown in FIG. 1 , a radiation source member 10 according to an embodiment is attached to a radiation source S that emits radiation. The radiation source member 10 has, for example, a circular mesh-like outer shape with a predetermined thickness. The radiation source member 10 is formed of, for example, a metal material such as aluminum or a resin material such as acrylic resin. The radiation source member 10 includes, for example, an attenuation section 10a that attenuates part of the radiation emitted from the radiation source S, and a transmission section 10b that transmits the rest of the radiation without attenuating it. For example, the attenuation section 10a is a mesh, and the transmission section 10b is a mesh formed in the attenuation section 10a.

[0022] The radiation source component 10 includes the attenuation portion 10a and the transmission portion 10b, and thereby sets the attenuation rate of the radiation emitted from the radiation source S within a predetermined range. The predetermined range is, for example, a range in which the count rate of the radiation by the radiation detector 31 attenuates between a reference count rate in the reference state and a count rate that is half the reference count rate, where the reference state is a state in which there is no self-absorption of radiation by the radiation source S.

[0023] Of the radiation emitted from the radiation source S, the radiation that passes through the attenuation portion 10a loses a portion of its energy. On the other hand, the radiation that passes through the transmission portion 10b does not lose any energy. In the case of beta rays emitted from the radiation source S, for example, the radiation source member 10 attenuates the beta rays without losing information about the maximum energy of the beta rays.

[0024] For example, the radiation source S shown in Fig. 1 includes a circular dish-shaped container 21 and a radioactive sample 23 held in the container 21. In the case of a beta ray source that emits beta rays, for example, the radiation source S includes: 89 Sr, 90 Sr, 90 Y, 137 Cs and 204 The sample 23 is a beta ray source using a predetermined nuclide such as Tl. 89 Sr, 90 Sr and 90 In the case of Y, it is a precipitate of strontium carbonate, etc. The surface of the sample 23 is provided with a thin coating film, such as a polyester film on which aluminum is vapor-deposited. The radiation source member 10 is placed, for example, on the surface of the sample 23 (e.g., the surface of the thin coating film) in the container 21.

[0025] As shown in FIGS. 2 and 3, a radioactivity measuring device 30 of the embodiment includes, for example, a radiation detector 31, a multiple pulse-height analyzer 33, and a processing device 35. The radiation detector 31 detects various types of radiation, such as gamma rays, X-rays, beta rays, and alpha rays. The radiation detector 31 may be, for example, a semiconductor detector using a semiconductor such as germanium, silicon, or a compound semiconductor (such as GaAs or CdTe), or a scintillation detector using various scintillators such as organic, inorganic, liquid, or gaseous. The radiation detector 31 of this embodiment may be, for example, a phoswich detector equipped with two different scintillators optically coupled to detect beta rays. For example, the scintillation detector may include a scintillator that emits scintillation light according to the energy of the radiation, and a photodetector that outputs a pulse signal according to the scintillation light.

[0026] The multi-pulse-height analyzer 33 is an MCA (Multi Channel Analyzer). The multi-pulse-height analyzer 33 calculates the pulse-height distribution of the output signal pulse (detection data) output from the radiation detector 31, that is, the count values ​​for each of the multiple channels associated with the pulse-height values. For example, when the radiation detector 31 outputs an output signal pulse having a pulse-height value corresponding to the energy of the radiation, the multi-pulse-height analyzer 33 creates an energy spectrum (spectral data) as the pulse-height distribution of the output signal pulse from the radiation detector 31.

[0027] The processing device 35 is an information processing device such as a personal computer, a smartphone, or a tablet terminal. A part of the processing device 35 includes a software function unit that functions when a processor such as a CPU (Central Processing Unit) executes a predetermined program. The software function unit is an ECU (Electronic Control Unit) that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. Note that a part of the processing device 35 may include an integrated circuit such as an LSI (Large Scale Integration).

[0028] The processing device 35 comprehensively controls the operations of, for example, the radiation detector 31, the multi-pulse-height analyzer 33, and auxiliary devices such as a sample changer. The processing device 35 performs processes such as calibration and inspection of the radiation detector 31 and the multi-pulse-height analyzer 33, spectral analysis, and nuclide analysis based on the energy spectrum of the radiation generated by the multi-pulse-height analyzer 33. The processing device 35 includes an input unit such as a touch panel that outputs signals according to input operations by an operator, various switches, a keyboard, etc. The processing device 35 also includes an output unit such as a display device that displays various information and data, and a speaker that outputs various sounds, etc.

[0029] 2, radiation emitted from the radiation source S or radiation emitted from the radiation source S and passing through the radiation source member 10 is detected by the radiation detector 31 inside the shielding body SH, for example. The shielding body SH has an outer shape, for example, a box shape that surrounds the sensitive portion of the radiation detector 31, the radiation source S, and the radiation source member 10. The radiation source S and the radiation source member 10 are disposed, for example, at predetermined positions appropriately separated from the sensitive portion of the radiation detector 31. The emission direction D of the radiation detected by the radiation source member 10 is, for example, the direction from the radiation source S and the radiation source member 10 toward the sensitive portion of the radiation detector 31. The shielding body SH is made of a radiation-shielding material such as lead or tungsten.

[0030] The operation of the radioactivity measuring device 30 of this embodiment will be described below. Fig. 4 is a diagram showing an example of the energy spectrum of beta rays obtained by the radioactivity measuring device 30 in each of the embodiment and the comparative example. Fig. 5 is a diagram showing an example of the correspondence relationship between the counting efficiency obtained by the radioactivity measuring device 30 according to the embodiment and the sample mass and mesh density. Fig. 6 is a diagram showing an example of the correspondence relationship between the counting efficiency obtained by the radioactivity measuring device 30 according to the embodiment and the weight of strontium carbonate precipitate.

[0031] The efficiency calibration of the radioactivity measuring device 30 according to the embodiment is performed based on the energy spectrum generated by measuring radiation for a combination of a radiation source S, such as a standard source of a predetermined nuclide, and one or more different radiation source components 10. For example, a combination of the radiation source S and one or more different radiation source components 10 is set to correspond to a plurality of radiation sources of the same nuclide but with different self-absorption depending on the volume, weight, etc. The processing device 35 acquires data on the correspondence relationship between a virtual quantity (e.g., mass, etc.) of the radiation source, which is associated with the attenuation rate of at least one radiation obtained by one or more different radiation source components 10, and the radiation counting efficiency. For example, if the radiation source S is 89 Sr, 90 Sr and 90 In the case of a beta ray source of Y, the virtual quantity of the radiation source associated with the attenuation rate of the radiation obtained by the radiation source member 10 is the mass of the strontium carbonate precipitate that constitutes the sample 23, or the like.

[0032] 4 is an example of a beta ray spectrum (without mesh) obtained for a radiation source S to which no radiation source component 10 is attached, and beta ray spectra (first mesh and second mesh) obtained for combinations of two different radiation source components 10 and the radiation source S. For example, the density of the attenuation portions 10a in the first mesh (mesh density D1) is relatively smaller than the density of the attenuation portions 10a in the second mesh (mesh density D2), and therefore the attenuation rate of beta rays in the first mesh is relatively smaller than the attenuation rate of beta rays in the second mesh. The comparative example shown in FIG. 4 is an example of a beta ray spectrum (with plate filter) when a plate filter such as an acrylic plate having a predetermined thickness is attached to the radiation source S instead of the radiation source component 10 of the embodiment, and a beta ray spectrum (without plate filter) when no plate filter is attached to the radiation source S.

[0033] In the comparative example shown in Figure 4, it is observed that in the case of beta rays passing through a plate-shaped filter, in addition to attenuation, some of the energy is lost, resulting in the loss of information on the maximum energy of the beta rays emitted from the radiation source S. In the embodiment, the attenuation rate of beta rays varies depending on the different radiation source members 10, and information on the maximum energy is retained by the beta rays passing through the transmission section 10b, so that it is possible to simulate, for example, multiple radiation sources S of the same nuclide but with different quantities such as volume and weight.

[0034] 5, the processing device 35 acquires a counting efficiency obtained from the energy spectrum of beta rays for the radiation source S alone, and a counting efficiency obtained from the spectrum of beta rays for each combination of a plurality of different radiation source members 10 and the radiation source S. The counting efficiency obtained for the radiation source S alone is the counting efficiency corresponding to the mass (sample mass) M0 of the sample 23 of the radiation source S. The plurality of different radiation source members 10 are, for example, two radiation source members 10 having different densities (mesh densities) of the attenuation portions 10a or different aperture ratios of the transmission portions 10b, where a first mesh density D1 corresponds to a virtual sample mass M1 and a second mesh density D2 (>D1) corresponds to a virtual sample mass M2 (>M1). The processing device 35 acquires the counting efficiency E (= C / B × 100) (%) based on, for example, the energy spectrum of beta rays, the total counting rate C (cps) in a predetermined energy range including the maximum energy of beta rays emitted from the radiation source S, and the radioactivity R (Bq) of the radiation source S, which is known in advance.

[0035] For example, as shown in FIG. 6, a radiation source S generates a precipitate of strontium carbonate as sample 23. 89 Sr, 90 Sr and 90 In the case of a beta ray source of Y, the processing device 35 acquires the counting efficiency E (= C / B × 100) (%) in the energy spectrum of the beta ray, for example, in the energy range from 100 keV to 2.5 MeV. 89 The maximum energy of Sr beta rays is about 1.495 MeV, 90The maximum energy of Sr beta rays is about 546 keV, 90 The maximum energy of Y beta rays is approximately 2.280 MeV. For example, the processing device 35 may be configured to perform the following operations using a combination of a plurality of different radiation source components 10 and radiation sources S: 89 Sr, 90 Sr and 90 For each nuclide Y, a plurality of data on the correspondence relationship between the precipitate weight (x) of strontium carbonate and the counting efficiency (y) is acquired. The processing device 35 fits the plurality of data with a predetermined function F(x) such as a polynomial of the precipitate weight (x) of strontium carbonate. The predetermined function F(x) is, for example, a quadratic function of the variable x or a function of degree 3 or higher. For example, 89 Sr, 90 Sr and 90 The predetermined functions F(x) for each nuclide of Y are the functions Fa(x), Fb(x), and Fc(x), respectively.

[0036] The processing device 35 uses a predetermined function F(x) to obtain a hypothetical counting efficiency (reference counting efficiency) when the variable x is zero, that is, when the precipitate weight (x) of strontium carbonate is zero and there is no self-absorption of beta rays by the radiation source component 10 and the radiation source S. The processing device 35 obtains the rate of self-absorption of beta rays by each of a plurality of different combinations of the radiation source component 10 and the radiation source S, that is, the attenuation rate of beta rays, from the ratio of the counting efficiency for each of the plurality of data to the reference counting efficiency. The processing device 35 sets the range of the attenuation rate of radiation by the radiation source component 10 as a range in which the count rate of radiation by the radiation detector 31 attenuates between the reference count rate in the reference state and a count rate that is half the reference count rate, for example, assuming that the reference state is one in which there is no self-absorption of radiation by the radiation source S.

[0037] As described above, the radiation source component 10 of the embodiment ensures a desired attenuation rate for radiation passing through the attenuation section 10a of the radiation source component 10, and also retains information about the energy emitted from the radiation source S by the radiation passing through the transmission section 10b. By combining the radiation source S with the radiation source component 10, it is possible to easily simulate multiple radiation sources S with different radiation attenuation rates. By setting the range of the radiation attenuation rate to a predetermined range in which the radiation attenuates between the reference count rate and a count rate that is half the reference count rate, the desired accuracy can be ensured when simulating multiple different radiation sources S. The radiation source member 10 can be easily formed by the mesh-like attenuation portion 10a and the mesh-like transmission portion 10b.

[0038] According to the embodiment of the radioactivity measuring device 30 and the efficiency calibration method for the radioactivity measuring device 30, the calibration points for efficiency calibration can be easily increased by using at least one radiation source component 10 without requiring a plurality of different radiation sources S, and the accuracy and reliability of the efficiency calibration of the radioactivity measuring device 30 can be improved while suppressing an increase in cumbersome work and costs.

[0039] (Variation) Modifications of the embodiment will be described below. Note that the same parts as those in the above-described embodiment will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified. In the above-described embodiment, the radiation source member 10 has a constant predetermined thickness, but is not limited thereto. For example, the thickness of the attenuation portion 10a and the thickness of the transmission portion 10b of the radiation source member 10 may be formed to vary along a predetermined direction, such as the radiation emission direction D. Fig. 7 is a perspective view showing a partly cutaway radiation source component 10A and a partly cutaway radiation source S according to a first modified example of the embodiment. Fig. 8 is a perspective view showing a partly cutaway radiation source component 10B and a partly cutaway radiation source S according to a second modified example of the embodiment.

[0040] 7, the radiation source member 10A of the first modified example has, for example, a concave curved surface recessed toward the sample 23 in the thickness direction of the radiation source S, and is provided with an attenuation portion 40a provided at the periphery and a transmission portion 40b provided at the center. The thickness of the transmission portion 40b is formed to be relatively thinner than the thickness of the attenuation portion 40a. 8, the radiation source member 10B of the second modified example has, for example, a convex curved surface that protrudes outward in the thickness direction of the radiation source S, and is provided with an attenuation portion 40a provided in the central portion and a transmission portion 40b provided in the peripheral portion. The transmission portion 40b is formed to be relatively thinner than the attenuation portion 40a.

[0041] In the above-described embodiment, first modification, and second modification, the outer shape of each of the radiation source components 10, 10A, and 10B is a mesh-like shape, but is not limited thereto. For example, the outer shape of each of the radiation source components 10, 10A, and 10B may be another shape, such as a plate-like shape, with voids or pores formed along a predetermined direction, such as the radiation emission direction D. Of the attenuation sections and transmission sections constituting each of the radiation source components 10, 10A, and 10B, by forming voids or pores in at least the transmission section, all but a portion of the radiation emitted from the radiation source S (i.e., all but the portion of the radiation that passes through the attenuation section) can be transmitted without attenuation. For example, the shape, material, etc. of the radiation source member 10 may be set by an appropriate radiation transport simulation.

[0042] In the above-described embodiment, the processing device 35 acquires the attenuation rate of beta rays by the radiation source component 10 and the radiation source S using the reference counting efficiency when the variable x in the predetermined function F(x) is zero, but this is not limiting. For example, the processing device 35 may acquire the rate of self-absorption of beta rays by each of a plurality of different radiation source components 10, i.e., the attenuation rate of beta rays, using as a reference the counting efficiency when the variable x in the predetermined function F(x) is the actual precipitate weight of strontium carbonate in the radiation source S.

[0043] In the above-described embodiment, the processing device 35 may set a weight for each piece of data when fitting the plurality of pieces of data with a predetermined function F(x). For example, the processing device 35 may set a weight that decreases as the attenuation rate of radiation by the radiation source component 10 increases.

[0044] In the above-described embodiment, the radiation detector 31 is a phoswich detector, but is not limited to this. For example, the radiation detector 31 may be another radiation detector such as a scintillation detector or a semiconductor detector.

[0045] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0046] 10...radiation source member, 10a...attenuation section, 10b...transmission section, 30...radioactivity measuring device, 31...radiation detector, 33...multiple pulse height analyzer (processing section), 35...processing device (arithmetic section), S...radiation source.

Claims

1. an attenuation unit that attenuates a portion of the radiation emitted from the radiation source; a transmitting portion that transmits the radiation other than the part of the radiation without attenuating it; Equipped with Setting the attenuation rate of the radiation within a predetermined range Radiation source components.

2. The predetermined range is a range in which the count rate of the radiation detected by the radiation detector attenuates between a reference count rate in the reference state where there is no self-absorption of the radiation by the radiation source and a count rate that is half the reference count rate. The radiation source member according to claim 1 .

3. A gap or pore is formed in the transmitting portion. The radiation source member according to claim 1 or 2.

4. The gaps or pores are formed along the radiation emission direction. The radiation source member according to claim 3 .

5. The thickness of the transmission portion is formed to be relatively thinner than the thickness of the attenuation portion. The radiation source member according to claim 1 or 2.

6. The thickness of the transmitting portion and the thickness of the attenuating portion are thicknesses along the radiation emission direction. The radiation source member according to claim 5 .

7. The transmitting portion is formed in a mesh shape. The radiation source member according to claim 1 .

8. one or more different radiation source elements according to claim 1 or claim 2; the radiation source to which the radiation source member is attached; a radiation detector that outputs a pulse signal corresponding to the energy of the radiation emitted from the radiation source or the energy of the radiation emitted from the radiation source and passed through the radiation source member; a processing unit that generates pulse-height distribution data having counts associated with each of a plurality of channels based on the pulse-height values ​​of the pulse signal; a calculation unit that acquires, based on the pulse-height distribution data, a counting efficiency of the radiation by the radiation detector for the radiation source or a combination of the radiation source and the radiation source component; Equipped with The calculation unit and acquiring data on a correspondence relationship between the amount of the radiation source associated with at least one of the attenuation rates obtained by the one or more different radiation source members and the counting efficiency. Radioactivity measuring device.

9. one or more different radiation source elements according to claim 1 or claim 2; a radiation source to which the radiation source member is attached; and a radiation detector that outputs a pulse signal corresponding to the energy of the radiation emitted from the radiation source or the energy of the radiation emitted from the radiation source and passed through the radiation source member; a processing unit that generates pulse-height distribution data having counts associated with each of a plurality of channels based on the pulse-height values ​​of the pulse signal; a calculation unit that acquires, based on the pulse-height distribution data, a counting efficiency of the radiation by the radiation detector for the radiation source or a combination of the radiation source and the radiation source component; A method for calibrating the efficiency of a radioactivity measuring device, comprising: the calculation unit includes a step of acquiring data on a correspondence relationship between the amount of the radiation source associated with at least one of the attenuation rates obtained by the one or more different radiation source members and the counting efficiency. Efficiency calibration method.

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