JP4894491B2 - Radiation transmission measuring apparatus and radiation transmission measuring method - Google Patents

Description

  The present invention relates to a technique for improving measurement accuracy in a radiation transmission measurement method.

  Conventionally, a radiation transmission measurement method is known as one of nondestructive inspection methods. The radiation transmission measurement method irradiates a sample with radiation, obtains a transmission image of the radiation transmitted through the sample, and measures the attenuation of radiation from the spatial distribution of the radiation intensity transmitted through the sample. It measures the distribution of substances and the thickness (quantity) of a substance layer.

  For example, Patent Document 1 describes a technique related to neutron radiography, which is one of the radiation transmission measurement methods. Neutron radiography is used to measure the water content of fuel cells, concrete materials, and the like.

In the radiation transmission measuring method described in Patent Document 1, a calibration curve is created in advance using a reference piece for creating a calibration curve, and subsequently, the amount of water in the sample is measured using the calibration curve.
Specifically, first, a neutron beam is irradiated to the reference piece, a transmission neutron image of the reference piece is obtained, and the attenuation amount (transmittance) of the neutron calculated from the transmission neutron image and the path of the neutron beam A calibration curve relating the attenuation of neutrons and the amount of moisture is created from the amount of moisture in the reference piece. Subsequently, the sample is irradiated with a neutron beam, a transmission neutron image of the sample is obtained, and the moisture content in the sample is calculated from the attenuation amount (transmittance) of the neutron calculated from the transmission neutron image using the prepared calibration curve. A quantity is calculated.

  In the radiation transmission measurement as described above, as a neutron source that emits a neutron beam, there are a neutron source that uses a neutron generated by a nuclear reaction in a nuclear reactor, or a neutron generated by colliding an electron accelerated by an accelerator with a target. Among these, the nuclear reactor is suitable for neutron radiography because a high-quality parallel neutron beam with a relatively large field of view can be obtained.

However, the number of neutrons scattered from the reactor to the port used for radiation transmission measurement and their intensity vary over time. For this reason, the amount of neutron contained in the neutron beam irradiated to the sample from the neutron source also varies over time, and a measurement error due to measurement occurs in the attenuation amount of the detected neutron.
In particular, when measuring the amount of water in the fuel cell by neutron radiography, a measurement accuracy of about several microns is required, but when the above measurement error occurs, an accurate measurement result is obtained. It becomes difficult.
JP 2005-265787 A

  In view of the above, in the present invention, in the radiation transmission measurement method, a higher measurement can be performed by correcting the obtained radiation transmission image (image processing) in consideration of fluctuations in the intensity of radiation applied to the sample. We propose a technique to provide accuracy.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in the radiation transmission measuring apparatus according to claim 1 , the irradiation of the sample with radiation and the detection of the radiation transmitted through the sample are performed at least a plurality of times, and the change in the amount of the measurement object inside the sample is measured. A sealable container having an accommodating portion formed therein, wherein the accommodating portion is an empty first reference piece, and the accommodating portion is filled with the same substance as a predetermined amount of the measurement object. A pair of reference pieces, an irradiation means for irradiating the pair of reference pieces and the sample simultaneously, a detection means for detecting radiation transmitted through the pair of reference pieces or the sample, and the detection means An imaging unit that captures the detected radiation and obtains a transmitted radiation image, and the detection by the detection unit and the imaging by the imaging unit are performed at least a plurality of times in a state where the amount of the measurement object in the sample is different. Got An image extraction means for obtaining a set of transmitted radiation images for each of the first reference piece, the second reference piece and the sample from the set of transmitted radiation images, and calculation based on the set of transmitted radiation images of the first reference piece using the correction equation, the first reference piece, quantification quantified based in a set of transmitted radiation image about the respective second reference block and the sample, one of the transmitted radiation image on the other transmitted radiation image Quantification processing means, metric standard creation means for obtaining a metric standard of the measurement object from each of the quantified transmission radiation images of the first reference piece and the second reference piece, and quantification of the sample Measurement value calculation means for obtaining a change in the amount of the measurement object inside the sample from a set of transmission radiation images and the measurement standard is provided.

The normalization means for normalizing each of the first reference piece, the second reference piece, and a set of transmitted radiation images of the sample quantified by the quantification means in the radiation transmission measuring device. Is further provided.

According to a third aspect of the present invention, the reference piece has a shape in which a radiation emission surface from the reference piece has a stepped shape, and the thickness of the accommodating portion in the traveling direction of the radiation changes discontinuously. .

In Claim 4 , it is a sealable container in which the accommodating part was formed, Comprising: The said accommodating part is an empty 1st reference piece, and the said accommodating part is satisfy | filled with the same substance as the measurement target object of predetermined amount. A second reference piece, a pair of reference pieces, a radiation irradiation means, a radiation detection means, an imaging means, an image extraction means, a quantification processing means, a measurement reference creation means, a measurement value calculation means, A step of irradiating the pair of reference pieces and the sample at the same time with the radiation irradiating means, and the pair of reference pieces or samples with the radiation detecting means. A set of imaging at least a plurality of times in a state where the amount of the measurement object in the sample is different. To obtain a transmission radiation image of And a step of obtaining a set of transmitted radiation images for each of the first reference piece, the second reference piece and the sample from the set of transmitted radiation images by the image extracting means; and Te, in the first by using the calculated correction equation based on a set of transmitted radiation image one reference piece, the first reference block, a set of transmitted radiation image about the respective second reference block and the sample, A step of quantifying one transmission radiation image based on the other transmission radiation image, and a set of transmission radiation images quantified in the first reference piece and the second reference piece by the measurement reference creating means; From the step of obtaining the measurement standard of the measurement object, the measured value calculation means, the set of transmission radiation images of the sample quantified, and the measurement standard, the measurement object inside the sample Obtaining a change in quantity, Is Dressings.

In Claim 5 , the said radiation transmission measuring apparatus is equipped with the normalization means, About each of a set of transmitted radiation images of the 1st reference piece, the 2nd reference piece, and the sample which were quantified by the said quantification means. The method further includes a step of normalizing.

According to a sixth aspect of the present invention, the reference piece has a shape in which a radiation emission surface from the reference piece has a step shape, and the thickness of the accommodating portion in the traveling direction of the radiation changes discontinuously. .

  As effects of the present invention, the following effects can be obtained.

  According to the present invention, in the radiation transmission measurement, the obtained radiation transmission image is corrected (image processing) in consideration of fluctuations in the intensity of the radiation applied to the sample, so that higher measurement accuracy is provided. Can do.

Next, embodiments of the invention will be described.
1 is a diagram showing an overall configuration of a radiation transmission measuring apparatus according to Embodiment 1 of the present invention, FIG. 2 is a perspective view of a reference piece, FIG. 3 is a sectional view of a first reference piece, and FIG. 4 is a second reference. FIG. 5 is a sectional view of a reference piece of another embodiment.
6 is a flowchart of the radiation transmission measurement process according to the first embodiment, FIG. 7 is a flowchart of the quantification process, FIG. 8 is a flowchart of the measurement reference creation process, FIG. 9 is a diagram illustrating the flow of image processing, and FIG. FIG. 11 is a diagram showing an example of the relationship between one position and transmitted neutron intensity, and FIG. 11 is a diagram showing an example of a conversion equation.
FIG. 12 is a flowchart of the radiation transmission measurement process according to the second embodiment.

  In the embodiments shown below, in a radiation transmission measurement method for measuring the distribution and amount of a measurement object in a sample, the radiation is a neutron beam, the sample is a fuel cell, and the measurement object in the sample is the fuel cell. It is assumed that the water is generated by power generation that exists inside. The reference piece is used to create a measurement standard (calibration curve) between water and neutron attenuation in this system.

  First, Example 1 of the present invention will be described.

In the radiation transmission measuring apparatus or the radiation transmission measuring method according to the first embodiment of the present invention, first, the hollow first reference piece 6 and the measurement object are respectively measured before and after reaction (after power generation) of the fuel cell. The second reference piece 7 filled with the sample T and the sample T are simultaneously irradiated with radiation to obtain a radiation transmission image, and the thickness of the material layer of the measurement object is determined from the attenuation amount of the radiation transmitted through the reference pieces 6 and 7. The relationship between (amount) and the radiation attenuation amount is obtained, and the thickness (amount) and distribution of the material layer of the measurement object are obtained based on the attenuation amount of the radiation transmitted through the sample T.
According to the present invention, in the radiation transmission measurement method, variations in measurement results based on fluctuations in the intensity of radiation applied to the sample are eliminated, so that measurement accuracy can be improved.

[Radiation transmission measuring device 10]
A configuration of the radiation transmission measuring apparatus 10 according to the present embodiment will be described.
As shown in FIG. 3, the radiation transmission measuring apparatus 10 includes a neutron source 13, a stage 12 on which a sample T as a subject and a reference piece 6, 7 are placed, a neutron detector 14, an imaging unit 15, and the like. And arithmetic processing means 16 are provided.
A collimator 18 is provided between the neutron source 13 and the subject, and the neutron flux supplied from the neutron source 13 is adjusted to a parallel beam.

  The neutron source 13 irradiates a sample T as an object and the reference pieces 6 and 7 with a neutron beam as radiation. The neutron source 13 is connected to a nuclear reactor (not shown), and neutrons are sent from the nuclear reactor. The neutron source 13 and the collimator 18 are arranged so that the surface of the subject can be irradiated with a neutron beam substantially perpendicularly.

  The neutron detector 14 is provided on the opposite side of the neutron source 13 with respect to the subject. The neutron detector 14 detects the neutron beam that has passed through the subject and passed through the subject (that is, the attenuated neutron beam attenuated mainly by water in the reference piece 7 or the sample T).

  In this embodiment, the neutron detector 14 is a scintillator, and when radiation is incident on a specific substance, the radiation energy is absorbed and fluorescence is emitted and the radiation is counted and analyzed (scintillation). Is called.

  The neutron detector 14 is provided with a fluorescent plate 14b that emits fluorescence in response to neutrons transmitted through the subject in a dark box 14a. The fluorescence has such a high luminance that the neutron transmitted through the subject is not attenuated, and the magnitude of the attenuation of the neutron is caused by the thickness of the water in the path of the neutron beam. That is, in the fluorescent plate 14b, the fluorescence brightness increases as the water thickness in the reference piece 7 or the sample T decreases, and the fluorescence brightness decreases as the water thickness increases. The fluorescence is reflected by the mirror 14c in the dark box 14a, and is indirectly taken into the imaging means 15 that reads the fluorescence luminance. As the imaging means 15, a fluorescent luminance camera is employed.

In the transmission neutron image (transmission radiation image) obtained by the imaging means 15, the amount (intensity) of neutrons that have passed through the subject appears as the density (contrast) of the fluorescence brightness. This transmitted neutron image is sent from the imaging means 15 to the arithmetic processing means 16.
In Example 1, the neutron detected by the neutron detector 14 is imaged at least a plurality of times by the imaging means 15 to obtain a set of transmission neutron images.

In the arithmetic processing means 16, arithmetic processing including image processing is performed based on the set of transmission neutron images, and the amount of moisture in the sample T and its distribution are output as measurement results.
Specifically, the arithmetic processing means 16 is an electronic computer including an arithmetic part, a control part, a storage part, an input part, an output part, etc., and is an image extraction means, a quantification processing means, a metric standard preparation means, a measurement It functions as value calculation means and output means.
The image extracting means is for obtaining a set of transmitted radiation images for each of the first reference piece 6, the second reference piece 7 and the sample T from the set of transmitted neutron images obtained by the imaging means 15. It is.
The quantification processing means is quantified for each of the first reference piece 6, the second reference piece 7, and the sample T using a correction formula calculated based on a set of transmission neutron images of the first reference piece 6. To obtain a set of transmitted neutron images.
The measurement standard creating means is for obtaining a measurement standard of the measurement object from a set of quantified transmission neutron images of the first reference piece 6 and the second reference piece 7.
The measurement value calculation means is for obtaining a change in the amount of the measurement object in the sample T from the set of quantified transmission radiation images of the sample T and the measurement standard.
The output means indicates the calculated amount of the measurement object inside the sample, pixel data or voxel data such as a grayscale image map or a color image map, or two-dimensional or three-dimensional coordinates and the amount of the measurement object. It is for display output or print output as a table or the like.
The detailed functions of the above means will be described later.

[Reference pieces 6 and 7]
Next, the reference pieces 6 and 7 will be described.
As shown in FIGS. 2 to 4, the two reference pieces 6 and 7 to be used are strictly the same shape, and are a sealable hollow container in which the accommodating portion 8 is formed. These reference pieces 6 and 7 are preferably composed of a material having high neutron permeability such as aluminum, for example, in order to exclude the influence on the attenuation of neutrons other than water.
In the first reference piece 6 which is one reference piece, the accommodating portion 8 formed inside is hollow. In the second reference piece 7 which is the other reference piece, water 9 (distilled water) which is the same substance as the object to be measured is filled in the accommodating portion 8 formed inside.

The reference pieces 6 and 7 have an outer shape in which a surface of the rectangular parallelepiped opposite to the incident surface of the neutron beam, that is, an emission surface from which the neutron beam exits from the reference pieces 6 and 7 is cut out in a stepped shape. Have. It is assumed that the neutron beam is incident on the incident surface of the reference pieces 6 and 7 substantially perpendicularly, travels in a straight line inside the reference pieces 6 and 7 and is emitted to the outside from the emission surface.
In the present embodiment, a staircase is formed in a substantially vertical direction on the emission surface of the reference pieces 6 and 7, but a staircase may be formed in a substantially horizontal direction.

The reference pieces 6 and 7 are formed with walls having a substantially constant width, and the outer shape of the reference pieces 6 and 7 is such that the receiving portion 8 which is a space formed therein has a substantially flat incident surface side and a discharge surface side. It will be stepped.
When a direction substantially parallel to the traveling direction of the neutron beam is a thickness direction and the thickness is a thickness D, a material layer having a thickness D is formed in the accommodating portion 8. That is, a gas layer having a thickness D exists in the path of the neutron beam of the first reference piece 6, and a layer made of the same material as the measurement object of thickness D is provided in the path of the neutron beam of the second reference piece 7. Will exist. And since the radiation | emission surface side of the accommodating part 8 is formed in step shape, the thickness D of the said material layer changes discontinuously regularly.

In the present embodiment, the reference pieces 6 and 7 have a 0th step between the lower end and the first stage, a first step between the first stage and the second stage,..., The (n-1) th stage and the upper end. between the n-th step, accommodating portion 8 has a thickness D ₀ of the zeroth step, accommodating portion 8 of the first step has a thickness D _1, ..., accommodating portion 8 of the n-th step is the thickness D _n . As described above, in the reference pieces 6 and 7, the thickness D of the accommodating portion 8 is different for each step, and the thicknesses D ₀ · D ₁ ··· are discontinuously and regularly from the 0th step to the nth step. D _n becomes smaller. That is, as the lower step, the thickness D of the accommodating portion 8 is larger and the material layer through which the neutron beam passes becomes thicker, and as the upper step, the thickness D of the accommodating portion 8 is smaller and the material layer through which the neutron beam passes. The (gas layer or liquid layer) becomes thin.

  In the reference pieces 6 and 7, the thickness D of the material layer (gas layer or liquid layer) is discontinuous for each container 8, and the thickness D is constant within the range of the step width (for example, 10 μm) of the same step. It is. Therefore, when creating a calibration curve, the measurement error is small, and the relationship between the path of the neutron beam incident on the reference pieces 6 and 7 and the thickness D of the liquid phase filled with water can be matched. Easy.

  However, the accommodating portion 8 is not limited to a shape in which the thickness D changes discontinuously and regularly, but has a shape in which the thickness D changes discontinuously and irregularly, It may be a shape in which D changes. For example, as shown in FIG. 5, the outer shape of the reference pieces 6, 7 can be substantially wedge-shaped, and the thickness D of the accommodating portion 8 can be continuously reduced from the lower end toward the upper end.

In the reference pieces 6 and 7, the thicknesses D _{0 to} D _n at each step of the accommodating portion 8 are measured in advance and recorded in the arithmetic processing means 16. That is, the incident position of the neutron beam of the reference pieces 6 and 7 is associated with the thicknesses D _{0 to} D _{n of} the accommodating portion 8 through which the neutron beam incident on the incident position passes and recorded in the arithmetic processing means 16. Is done. The thickness D ₀ to D _n of the accommodating portion 8, the thickness of the liquid layer in each step, instead of the thickness D ₀ to D _n, or with the thickness D ₀ to D _n, the water content Can be recorded in correspondence with the incident position of the neutron beam.

  As described above, since the attenuation amount of the neutron beam varies depending on the thickness of the liquid layer of the accommodating portion 8 of the second reference piece 7, the position of each step of the accommodating portion 8 and the thickness of the liquid layer (water content) ) And the neutron attenuation of the neutron beam that has passed through the liquid layer of that thickness, and by plotting the relationship, a calibration curve representing the relationship between the moisture content and the neutron attenuation can be created. is there.

[Radiation transmission measurement procedure]
Then, the procedure of the radiation transmission measurement using the said radiation transmission measuring apparatus 10 is demonstrated using FIGS.
Hereinafter, a fuel battery cell that does not contain moisture as a measurement object before power generation is referred to as “sample T before reaction”, and fuel that contains water as a measurement object after power generation is performed. The battery cell is described as “sample T after reaction”.

First, the sample T before reaction, the first reference piece 6 and the second reference piece 7 are placed on the stage 12. The sample T, the first reference piece 6 and the second reference piece 7 are arranged in parallel on the stage 12 or the first reference piece 6 and the second reference piece on the sample T placed on the stage 12. 7 can be placed side by side.
These subjects are irradiated with a neutron beam from the neutron source 13. Neutrons that have passed through the subject are detected by the neutron detector 14, and a transmission neutron image in which the amount of neutrons is expressed as the intensity of fluorescence brightness is captured by the imaging means 15. The transmission neutron image is referred to as “first transmission image N ₁ ”.
This primary transmission image N ₁ is transmitted from the imaging means 15 to the arithmetic processing means 16 and stored in the arithmetic processing means 16 (S1).

Subsequently, the sample T after reaction, the first reference piece 6 and the second reference piece 7 are placed on the stage 12 this time. The sample T after the reaction, the first reference piece 6 and the second reference piece 7 are arranged in the same manner as when the sample T before the reaction was measured.
These subjects are irradiated with a neutron beam from the neutron source 13. Neutrons that have passed through the subject are detected by the neutron detector 14, and a transmission neutron image in which the amount of neutrons is expressed as the intensity of fluorescence brightness is captured by the imaging means 15. The transmission neutron image is referred to as “secondary transmission image N ₂ ”.
This secondary transmission image N ₂ is transmitted from the imaging means 15 to the arithmetic processing means 16 and stored in the arithmetic processing means 16 (S2).

In the arithmetic processing means 16 that has acquired the first transmission image N ₁ and the second transmission image N ₂ , these transmission neutron images are read out (S 3) and exist in the sample T after the reaction. Analysis for calculating the amount of water (water distribution) is started.

When the analysis processing is started, first, the arithmetic processing means 16 determines the image of the portion related to the first reference piece 6 and the second reference image from the first transmission image N ₁ and the second transmission image N _2. An image of a portion related to the piece 7 and an image of a portion related to the sample T are extracted (S4).
When extracting the analysis image, the contour of the reference piece 6 reflected in the first transmission image N ₁ is specified from the shape data and position data of the reference piece 6 set in advance in the arithmetic processing means 16, and the contour is used as the outline. The surrounded portion can be extracted as the first transmission image N ₁ of the portion related to the first reference piece 6. Similarly, in the second order transmission image N _2, it is possible to extract the second transmission image N ₂ portion according to the first reference piece 6.
Similarly to the above, for the second reference piece 7 and the sample T, it is possible to extract the primary transmission image N ₁ and the secondary transmission image N ₂ relating to the respective portions.

Next, the arithmetic processing means 16 quantifies the secondary transmission image N ₂ based on the primary transmission image N ₁ , and performs a process for eliminating the difference in neutron beam intensity when these are imaged. (S5).

As shown in FIG. 7, in the quantification process, the arithmetic processing means 16 shows the relationship between the reference piece position and the transmitted neutron intensity based on the first transmission image N ₁ of the first reference piece 6, for example, FIG. As shown in ( ₅ ), it approximates to a linear expression (Expression 1: y = α ₁ x + β ₁ ) (S51).

The “reference piece position” is defined as zero on one side of the neutron beam incident surface of the reference piece 6 where the thickness D of the accommodating portion 8 changes, and 1 on the other side. The relative position on the reference piece 6 in this case. For example, as shown in FIG. 3, in the reference piece 6, the end on the side where the thickness D of the accommodating portion 8 is the largest is the reference piece position 0, and the end on the side where the thickness D of the accommodating portion 8 is the smallest is the reference piece. One position 1 is set.
Further, the transmitted neutron intensity is converted based on an expression or a table or the like set in advance in the arithmetic processing means 16 from the fluorescence brightness that appears as shading in the first transmission image N ₁ of the first reference piece 6. Can be obtained.

Subsequently, similarly to the above-described processing, the arithmetic processing means 16 determines the relationship between the reference piece position and the transmitted neutron intensity based on the second transmission image N ₂ of the first reference piece 6, for example, as shown in FIG. As shown, it approximates to a linear expression (Expression 2: y = α ₂ x + β ₂ ) (S52).

Then, the arithmetic processing unit 16, the equation 1 and compares the slope alpha ₁ and alpha ₂ Formula 2 (S53), these differences to determine whether it is within a predetermined threshold range alpha (S54 ).
When the difference between α ₁ and α ₂ is within the range of the predetermined threshold α (NO in S54, 1 after the reaction in FIG. 10), that is, when the slopes of Equation 1 and Equation 2 are substantially the same The arithmetic processing means 16 compares the intercepts β ₁ and β ₂ of the equations 1 and ₂ and corrects the intercept β ₂ so that the intercept of the equation ₂ matches the intercept of the equation 1 (translation constant). Is calculated (S55).

On the other hand, when the difference between α ₁ and α ₂ exceeds a predetermined threshold value α (YES in S54 and 2 after reaction in FIG. 10), that is, when the slopes of Equation 1 and Equation 2 are different, the arithmetic processing means 16 calculates a correction formula for performing correction so that Formula 2 is matched with Formula 1 (S59).

Then, the arithmetic processing means 16 corrects each secondary transmission image N ₂ of the first reference piece 6, the second reference piece 7, and the sample T using the calculated correction formula (S56), and corrects the correction. The subsequent secondary transmission image N _2a is saved and stored (S57).
By the processing so far, the corrected secondary transmission images N _2a of the first reference piece 6, the second reference piece 7, and the sample T are quantified into the primary transmission image N ₁ . It will be.

Returning to FIG. 6, the arithmetic processing means 16 further applies the first reference piece 6 to the corrected second transmission image N _{2a of} the first reference piece 6, the second reference piece 7, and the sample T. When the each of the first order transmission images N ₁ original image and the second reference piece 7 and the sample T, performs a shading correction is normalized (S6). Hereinafter, this normalized image is referred to as a post-quantification image N _2b .
At the time of normalization, the primary transmission image N ₁ is divided from the corrected secondary transmission image N _2a to reduce the density unevenness of the neutron beam and the sensitivity unevenness in the image sensor, and to make the image easy to discriminate. _Therefore , the overall brightness of the corrected second transmission image N _2a is corrected.

Through the above processing, the arithmetic processing means 16 can obtain the quantified image N _2b for each of the first reference piece 6, the second reference piece 7, and the sample T. In this post-quantification image N _2b , variations in the amount of neutron contained in the neutron beam are eliminated.
Subsequently, the arithmetic processing means 16 performs a process for creating a metric reference (S7).

As shown in FIG. 8, in the measurement reference creation process, the arithmetic processing means 16 divides the quantified image N _2b related to the first reference piece 6 from the quantified image N _2b related to the second reference piece 7, Normalization is performed with a typical shading correction (S71). As a result, a metric reference image N _{3 in} which the degree of neutron intensity (neutron attenuation) attenuated by the water inside the second reference piece 7 is represented by shading can be obtained.

Further, the arithmetic processing means 16 is configured to detect the neutron attenuation amount indicated by the measurement reference image N ₃ , the position of each step of the accommodating portion 8 of the second reference piece 7 set in advance and the amount of moisture (or liquid layer). since the thickness D ₀ to D _n) and a transformation equation defining the relationship between the neutron attenuation and water content (for example, to create a Figure 11) (S72).
In this way, in the processing means 16, the water inside the reference piece such as the time variation of the irradiated neutron beam, the outer frame of the reference pieces 6 and 7, the amount of moisture in the atmosphere through which the neutron beam passes, etc. It is possible to create a conversion formula from which neutron attenuation factors other than are removed.

Subsequently, the arithmetic processing means 16 performs a process of calculating the moisture content inside the sample T using the above conversion formula (measurement standard) (S8).
First, the arithmetic processing means 16 applies the neutron attenuation amount represented by the density in the post-quantification image N _2b of the portion related to the sample T to the above-described conversion equation, thereby obtaining the moisture content (moisture content) of the sample T. Distribution).
Then, the arithmetic processing means 16 uses the calculated moisture content of the sample T as pixel data or voxel data such as a grayscale image map or a color image map, or a table indicating two-dimensional or three-dimensional coordinates and the moisture content. Output (S9).

  According to the procedure of the radiation transmission measurement described above, in addition to the neutron attenuation factors other than water generated by the reaction inside the sample T, such as the constituent material of the sample T and the amount of moisture in the atmosphere through which the neutron beam passes, Since measurement results in which measurement errors due to variations in the intensity and density of the irradiated neutron beam are eliminated can be obtained, the measurement accuracy can be improved.

A radiation transmission measuring apparatus 10 according to Example 2 of the present invention will be described.
In the first embodiment, in order to measure water generated by power generation and the like existing inside the fuel battery cell, the neutron detected by the neutron detector 14 is imaged at least a plurality of times by the imaging means 15, and A set of transmitted neutron images is obtained, and the amount of the measurement object inside the sample is calculated based on the set of transmitted neutron images. However, it is not necessarily limited to obtaining a plurality of transmission neutron images by imaging a plurality of times, and depending on the sample, the amount of the measurement object can be calculated based on one transmission neutron image. In the second embodiment, a radiation transmission measuring apparatus 10 and a radiation transmission measuring method configured to calculate the amount of the measurement object based on one transmission neutron image will be described.

  Since the configuration of the radiation transmission measuring apparatus 10 other than the arithmetic processing means 16 is the same as that of the radiation transmission measuring apparatus 10 described in the first embodiment, detailed description thereof is omitted.

The arithmetic processing means 16 included in the radiation transmission measuring apparatus 10 is an electronic computer including a calculation unit, a control unit, a storage unit, an input unit, an output unit, and the like, and includes an image extraction unit, a measurement standard creation unit, It functions as a measurement value calculation means and an output means.
The image extracting means is for extracting and obtaining transmitted radiation images of the first reference piece, the second reference piece, and the sample from the transmitted radiation image.
The measurement reference creation means is for obtaining a measurement reference of the measurement object from the transmitted radiation images of the first reference piece and the second reference piece.
The measurement value calculation means is for obtaining the amount of the measurement object inside the sample from the transmitted radiation image of the sample and the measurement standard.
The output means indicates the calculated amount of the measurement object inside the sample, pixel data or voxel data such as a grayscale image map or a color image map, or two-dimensional or three-dimensional coordinates and the amount of the measurement object. It is for display output or print output as a table or the like.

Next, the flow of processing for radiation transmission measurement in the radiation transmission measuring apparatus 10 having the above configuration will be described.
The radiation transmission measurement method according to the present embodiment is preferably applied when the sample T has no radiation attenuation factor other than moisture or when an outline of the moisture distribution of the sample T is obtained.

First, the sample T before reaction, the first reference piece 6 and the second reference piece 7 are placed on the stage 12. The sample T, the first reference piece 6 and the second reference piece 7 are arranged in parallel on the stage 12 or the first reference piece 6 and the second reference piece on the sample T placed on the stage 12. 7 can be placed side by side.
These subjects are irradiated with a neutron beam from the neutron source 13. Neutrons that have passed through the subject are detected by the neutron detector 14, and a transmission neutron image in which the amount of neutrons is expressed as the intensity of fluorescence brightness is captured by the imaging means 15. The transmission neutron image is referred to as “transmission image N ₅ ”.
This transmitted image N ₅ is transmitted from the imaging means 15 to the arithmetic processing means 16 and stored in the arithmetic processing means 16 (S81).

In the arithmetic processing means 16 that has acquired the transmission image N ₅ , the transmission neutron image is read (S 82), and an analysis for calculating the amount of water (water distribution) present in the sample T after the reaction is started. Is done.

When the analysis process is started, first, the arithmetic processing unit 16, a transmission image N _5, an image of a portion of the first reference piece 6, an image of a portion of the second reference piece 7, according to the sample T The partial images are extracted (S83).
At the time of extraction of the analysis image, the contour of the reference piece 6 reflected in the transmission image N ₅ is specified from the shape data and position data of the reference piece 6 set in advance in the arithmetic processing means 16, and is surrounded by the outline. The part can be extracted as an analysis image of the part related to the first reference piece 6. The second reference piece 7 and the sample T can be similarly extracted.

Next, the arithmetic processing means 16 creates a measurement standard (S84).
First, the arithmetic processing means 16 divides the transmission image N ₅ related to the first reference piece 6 from the transmission image N ₅ related to the second reference piece 7 and normalizes it by general shading correction. Thereby, the metric reference image N _{6 in} which the neutron intensity (neutron attenuation amount) attenuated by the water inside the second reference piece 7 is represented by shading can be obtained.

Further, the arithmetic processing means 16 is configured to calculate the neutron attenuation shown by the measurement reference image N ₆ , the position of each step of the accommodating portion 8 of the second reference piece 7 set in advance and the amount of water (or liquid layer). From the thickness D _{0 to} D _n ), a conversion formula (for example, FIG. 11) that defines the relationship between the neutron attenuation amount and the moisture amount is created.
In this way, in the processing means 16, the water inside the reference piece such as the time variation of the irradiated neutron beam, the outer frame of the reference pieces 6 and 7, the amount of moisture in the atmosphere through which the neutron beam passes, etc. It is possible to create a conversion formula from which neutron attenuation factors other than are removed.

Subsequently, the arithmetic processing means 16 performs a process of calculating the moisture content inside the sample T using the above conversion formula (measurement standard) (S85).
The arithmetic processing means 16 applies the neutron attenuation represented by the shading in the transmission image N _{5 of the} portion related to the sample T to the above-described conversion equation, thereby calculating the moisture content (moisture content distribution) of the sample T. calculate.
Then, the arithmetic processing means 16 uses the calculated moisture content of the sample T as pixel data or voxel data such as a grayscale image map or a color image map, or a table indicating two-dimensional or three-dimensional coordinates and the moisture content. Output (S86).

  As described above, radiation is simultaneously applied to the reference pieces 6 and 7 for calculating the amount of moisture to be measured and the sample T, and using the information appearing in the same image, the creation of the measurement reference and the measurement reference The measurement value is calculated using, that is, correction of the obtained radiographic image (image processing) is performed in consideration of fluctuations in the intensity of radiation irradiated to the sample, so that higher measurement accuracy is achieved. Can be provided.

  The reference piece of the present invention can be generally used for measuring the radiation transmission of a sample. Examples of the sample include fuel battery cells such as FC automobiles.

The figure which shows the whole structure of the radiation transmission measuring apparatus which concerns on Example 1 of this invention. The perspective view of a reference | standard piece. Sectional drawing of a 1st reference | standard piece. Sectional drawing of a 2nd reference | standard piece. Sectional drawing of the reference | standard piece of another form. 3 is a flowchart of a radiation transmission measurement process according to the first embodiment. The flowchart of a quantification process. The flowchart of a measurement reference | standard preparation process. The figure explaining the flow of image processing. The figure which shows an example of the relationship between a reference | standard piece position and transmitted neutron intensity | strength. The figure which shows an example of a conversion type | formula. 9 is a flowchart of radiation transmission measurement processing according to the second embodiment.

T sample 6 first reference piece 7 second reference piece 8 container 9 water 10 radiation transmission measuring device 12 stage 13 neutron source 14 neutron detector 15 imaging means 16 arithmetic processing means 18 collimator

Claims (6)

In the radiation transmission measuring apparatus for measuring the change in the amount of the measurement object inside the sample by performing irradiation of the sample with radiation and detecting the radiation transmitted through the sample at least several times,
An airtight container having a housing portion formed therein, wherein the housing portion is an empty first reference piece, and the housing portion is filled with a predetermined amount of the same substance as the measurement object. A pair of reference pieces,
An irradiation means for simultaneously irradiating the pair of reference pieces and the sample with radiation;
Detection means for detecting radiation transmitted through the pair of reference pieces or sample;
An imaging means for obtaining a transmitted radiation image by imaging radiation detected by the detection means;
From a set of transmitted radiation images obtained by performing the detection by the detection unit and the imaging by the imaging unit at least a plurality of times in a state where the amount of the measurement object in the sample is different, the first reference piece and the second reference piece Image extraction means for obtaining a set of transmitted radiation images for each piece and sample;
One transmission in a set of transmission radiation images for each of the first reference piece, the second reference piece and the sample using a correction formula calculated based on the set of transmission radiation images of the first reference piece. Quantification processing means for quantifying the radiographic image based on the other transmitted radiographic image;
A measurement standard creating means for obtaining a measurement standard of the measurement object from each of the quantified sets of transmission radiation images of the first reference piece and the second reference piece;
A measurement value calculating means for obtaining a change in the amount of the measurement object inside the sample from the set of quantified transmission radiation images of the sample and the measurement standard;
A radiation transmission measuring apparatus comprising: In the radiation transmission measuring device,
Normalizing means for normalizing each of a set of transmitted radiation images of the first reference piece, the second reference piece and the sample quantified by the quantifying means;
The radiation transmission measuring device according to claim 1, further comprising: The reference piece has a shape in which the radiation emission surface from the reference piece has a stepped shape, and the thickness of the accommodating portion in the traveling direction of the radiation changes discontinuously,
The radiation transmission measuring apparatus according to claim 1 or 2. An airtight container having a housing portion formed therein, wherein the housing portion is an empty first reference piece, and the housing portion is filled with a predetermined amount of the same substance as the measurement object. Radiation transmission measurement comprising a pair of reference pieces, radiation irradiation means, radiation detection means, imaging means, image extraction means, quantification processing means, measurement reference creation means, and measurement value calculation means Using the device,
A step of irradiating the pair of reference pieces and the sample simultaneously with the radiation irradiation means; and
An object to be measured in the sample is to detect the radiation transmitted through the pair of reference pieces or the sample by the radiation detection unit and to image the radiation detected by the detection unit by the imaging unit. Performing a set of transmitted radiation images at least multiple times with different amounts of
Obtaining a set of transmitted radiation images for each of the first reference piece, the second reference piece and the sample from the set of transmitted radiation images by the image extraction means;
In the quantification processing means, using a correction formula calculated based on a set of transmission radiation images of the first reference piece, a set of each of the first reference piece, the second reference piece, and the sample Quantifying one transmitted radiation image based on the other transmitted radiation image in the transmitted radiation image;
Obtaining a measurement reference of a measurement object from a set of transmitted radiation images of each of the first reference piece and the second reference piece by the measurement reference creating means;
In the measurement value calculation means, obtaining a change in the amount of the measurement object inside the sample from the quantified set of transmission radiation images of the sample and the measurement standard,
A radiation transmission measurement method comprising: The radiation transmission measuring device comprises a normalizing means,
Normalizing each of a set of transmitted radiation images of the first reference piece, the second reference piece and the sample quantified by the quantification means;
The radiation transmission measuring method according to claim 4, further comprising: The reference piece has a shape in which the radiation emission surface from the reference piece has a stepped shape, and the thickness of the accommodating portion in the traveling direction of the radiation changes discontinuously,
The radiation transmission measuring method according to claim 4 or 5.

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