JP2013036984A - Fluorescence x-ray analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescence X-ray analyzer capable of identifying elements and radioactive materials contained in a measurement object sample.SOLUTION: The fluorescence X-ray analyzer of the present invention includes a fluorescence X-ray detector for measuring an X-ray region (1 keV to 50 keV), a γ-ray detector for measuring a γ-ray region (50 keV to 1.5 MeV), and analysis processing means. An excitation X-ray tube irradiates a measurement object sample with X-rays. The fluorescence X-ray detector detects fluorescence X-rays intrinsic to elements contained in the measurement object sample, and the γ-ray detector detects γ-rays intrinsic to nuclear species. The analysis processing means obtains a fluorescence X-ray spectrum and a γ-ray spectrum. According to necessity, the analysis processing means identifies elements contained in the sample on the basis of the fluorescence X-ray spectrum and obtains the contents thereof, and identifies the nuclear species of radioactive materials on the basis of the γ-ray spectrum and obtains the contents thereof.

Description

  The present invention relates to a fluorescent X-ray analyzer, and more particularly to a fluorescent X-ray analyzer with a radioactive substance detection function, for example.

  Energy-dispersed fluorescence is a simple method for measuring the content of elements in soil, waste materials (including recycled materials), foods, toys, and electronic materials, especially harmful heavy metals (such as Hg, Pb, As, and Cd). X-ray devices are very useful. Screening measurement based on regulations on electrical and electronic parts (WEEE / RoHS, ELV, J-MOSS), regulations on toys (EN71, ASTM, ST standards), and soil regulations (enforcement example of the Soil Contamination Countermeasures Law: JIS K0470 compliant) It is recognized as useful.

  On the other hand, in recent years, a demand for detecting whether or not a radioactive substance is contained in these objects to be measured is rapidly increasing. In particular, in the wake of the Great East Japan Earthquake, radioactive materials were used to investigate the presence of radioactive contamination associated with nuclear accidents at nuclear power plants and soil contamination of harmful substances caused by tsunami damage, and to examine or confirm the impact on crops. There is a need for an analyzer that can accurately determine the nuclide identification and content. In general, in order to achieve these objects, an energy dispersive X-ray fluorescence analyzer is used for elemental analysis, and a radiation survey meter or γ-ray spectrum meter is used for measurement of radioactive substances. Conventionally, elemental analysis and analysis of radioactive materials have been performed separately using two measuring devices with different functions.

JP-A-7-209493 discloses a combination of a capture γ-ray analyzer that irradiates a radioactive waste from a neutron source with thermal neutrons and a fluorescent X-ray analyzer that irradiates the radioactive waste with X-rays from the X-ray generator. Consists of.

A conventional X-ray fluorescence analyzer can determine the element in the sample to be measured and its content, but it cannot identify the nuclide even if the sample contains a radioactive substance.
On the other hand, Patent Document 1 does not measure γ-rays generated by radioactive waste itself, but detects and analyzes captured γ-rays generated by thermal neutron irradiation. In addition, since the fluorescent X-ray and the captured γ-ray are separately measured by moving one sample, the measurement takes time, the measurement efficiency is poor, and the measurement apparatus becomes expensive.
Furthermore, placing the γ-ray detector and the X-ray detector close to each other adversely affects the detection and analysis of the fluorescent X-ray detector that detects a trace amount of elements, making it difficult to accurately analyze the fluorescent X-ray. Sometimes.

Therefore, the main object of the present invention is to obtain a fluorescent X-ray spectrum depending on an element contained in a sample and a γ-ray spectrum depending on a radionuclide nuclide using a single analyzer. An X-ray fluorescence analyzer is provided.
Another object of the present invention is to determine the elements contained in the sample and the content thereof using a single analyzer, and to identify the radionuclide nuclide contained in the sample and the content thereof. Is to provide a fluorescent X-ray analyzer.
Still another object of the present invention is to provide a fluorescent X-ray analyzer capable of quickly identifying the element and nuclide and the content thereof and having high measurement efficiency.

  The X-ray fluorescence analyzer of the first invention comprises a fluorescent X-ray detector for measuring an X-ray region (1 keV to 50 keV) (14 if showing the correspondence with the example. Analysis to obtain a fluorescent X-ray spectrum and a γ-ray spectrum by operating a γ-ray detector (15) that measures a γ-ray region (50 keV to 1.5 MeV), a fluorescent X-ray detector, and a γ-ray detector. And a processing means.

  According to a second invention, in the first invention, the analysis processing means (16, 17, 18, 20) operates the fluorescent X-ray detector (14) and the γ-ray detector (15) at the same time, so that the fluorescence X It is characterized in that a line spectrum and a γ-ray spectrum are obtained simultaneously.

  According to a third invention, in the first invention, the analysis processing means operates the fluorescent X-ray detector (14) and the γ-ray detector (15) independently of each other, so that the spectrum of the fluorescent X-rays and the γ-rays are obtained. The spectrum is obtained separately.

  The X-ray fluorescence analyzer of the fourth invention comprises a detector capable of simultaneously measuring an X-ray region (1 keV to 50 keV) and a γ-ray region (50 keV to 1.5 MeV), and operates the detector. And an analysis processing means for simultaneously obtaining a fluorescent X-ray spectrum and a γ-ray spectrum.

  According to a fifth aspect of the present invention, in the first to third aspects of the present invention, a mounting unit for placing the sample to be measured (1), a sample chamber (11c) for housing the placing unit and the sample to be measured, and a sample to be measured (1 ) Is further provided with a fluorescent X-ray measurement excitation X-ray tube (12) for irradiating X-rays.

  In a sixth aspect based on the fifth aspect, the fluorescent X-ray measurement excitation X-ray tube irradiates the sample to be measured from below the mounting portion. The fluorescent X-ray detector and the γ-ray detector are disposed below the placement unit.

  According to a seventh invention, in the fifth invention, the excitation X-ray tube for fluorescent X-ray measurement irradiates the sample to be measured from below the mounting portion. The fluorescent X-ray detector is disposed below the placement unit. The γ-ray detector is disposed above the sample to be measured placed on the placement unit.

  In an eighth aspect based on the fifth aspect, the fluorescent X-ray measurement excitation X-ray tube irradiates the sample to be measured from below the mounting portion. The fluorescent X-ray detector is disposed below the placement unit. The γ-ray detector is disposed on the side surface of the sample to be measured placed on the placement unit.

  According to a ninth invention, in the fifth invention, when the fluorescent X-ray detector (14) irradiates the sample to be measured (1) with the X-ray generated from the X-ray tube, Fluorescence X-rays specific to the elements generated by the excitation of the contained elements are detected. The γ-ray detector (15) detects γ-rays emitted from the sample to be measured (1) in connection with (or simultaneously with) the detection of the fluorescent X-rays by the fluorescent X-ray detector. The analysis processing means (16, 17, 18, 20) specifies the element contained in the sample to be measured based on the spectrum of the fluorescent X-ray detected by the fluorescent X-ray detector (14) and contains the specified element. At the same time as determining the amount, the nuclide of the radioactive substance contained in the sample to be measured is specified based on the spectrum of the γ-ray detected by the γ-ray detector (15), and the content of the specified nuclide is determined.

A fluorescent X-ray analysis apparatus according to a tenth aspect of the present invention includes a mounting portion (11b) for placing a sample to be measured, a sample chamber (11c) for housing the sample to be measured, and a sample to be measured placed on the placing portion. A fluorescent X-ray detector (14) for measuring an X-ray region (1 keV to 50 keV) having a fluorescent X-ray measurement excitation X-ray tube (12) for irradiating X-rays to the X-ray, and a γ-ray region Γ-ray detector (15) for measuring (50 keV to 1.5 MeV) and the power supplied to the excitation X-ray tube for fluorescent X-ray measurement are controlled, and the detection output of the fluorescent X-ray detector and the γ-ray detector Analysis processing means (16, 17, 18, 20) for performing analysis processing based on the detection output is provided.
The fluorescent X-ray detector detects fluorescent X-rays generated by excitation of elements contained in the sample to be measured when the sample to be measured is irradiated with X-rays generated by the excitation X-ray tube for fluorescent X-ray measurement. The γ-ray detector detects γ-rays emitted from the sample to be measured in connection with the detection of the fluorescent X-rays by the fluorescent X-ray detector. The analysis processing means specifies the element contained in the sample to be measured based on the spectrum of the fluorescent X-ray detected by the fluorescent X-ray detector, obtains the content of the specified element, and is detected by the γ-ray detector. The radionuclide nuclide contained in the sample to be measured is specified based on the γ-ray spectrum, and the content of the specified nuclide is obtained.

  In an eleventh aspect based on the ninth or tenth aspect, the analysis processing means determines whether or not the specified element is a radioactive substance. After determining that the specified element is a radioactive substance, the nuclide of the radioactive substance is determined. It is characterized by performing a process for determining the content of the specified nuclide.

According to the present invention, it is possible to obtain a fluorescent X-ray spectrum that depends on an element contained in a sample and a γ-ray spectrum that depends on the nuclide of the radioactive substance using one analyzer, and the element and the radioactive substance. An X-ray fluorescence analyzer useful for identifying the nuclide is obtained.
Further, according to another invention, it is possible to determine the element contained in the sample and the content thereof using one analyzer, and to identify the nuclide of the radioactive substance contained in the sample and the content thereof. An X-ray fluorescence analyzer capable of determining the amount is obtained.
In addition, it is possible to quickly and efficiently analyze and measure the identification of elements and their contents and the identification and contents of nuclides.

1 is an external view of a fluorescent X-ray analyzer main body according to an embodiment of the present invention. 1 is a block diagram illustrating the principle of a fluorescent X-ray analyzer according to an embodiment of the present invention. FIG. 3 is a detailed block diagram of an analysis control circuit and a personal computer in FIG. 2. It is a schematic diagram for demonstrating the existing condition of a to-be-measured sample, and extraction. It is a flowchart for demonstrating the operation | movement of the analysis and measurement of the element and radioactive substance in a to-be-measured sample. It is a block diagram of the fluorescent X-ray-analysis apparatus of the other Example of this invention. It is a block diagram of the fluorescent X-ray-analysis apparatus of the other Example of this invention.

Example 1
In FIG. 1, an X-ray fluorescence analyzer according to an embodiment of the present invention includes a main body 10 and a measurement personal computer (hereinafter simply referred to as “measurement personal computer” or simply “personal computer”) 20.
The main body 10 includes a housing 11. A lid member (hereinafter abbreviated as “lid”) 11 a is supported on the housing 11 so as to be openable and closable upward. The inside of the main body 10 is exposed when the lid 11a is opened, and a mounting portion (or sample holding table) 11b for holding a sample is provided. The mounting portion 11b separates the inside of the housing 11 from top to bottom, so that the housing 11 has an upper sample chamber (11c in FIG. 2) and a lower device storage chamber (FIG. 2) for storing various devices or parts. 11d). In addition, you may support the mounting part 11b rotatably.
The main body 10 is provided with a lock mechanism (not shown) associated with the lid 11a and a switch for detecting the open / closed state of the lid 11b. Further, a plate-like shielding member (not shown) such as lead is attached to the wall surface inside the main body 10. As a result, the inside of the housing 11 is sealed to prevent X-rays and γ-rays from leaking to the outside.
A personal computer 20 is connected to the main body 10 via a cable.

  In FIG. 2, a fluorescent X-ray measurement excitation X-ray tube (hereinafter abbreviated as “X-ray tube”) 12 is placed on the sample 1 to be measured in the equipment storage chamber 11 d of the main body 10 and below the mounting portion 11 b. It arrange | positions so that an X-ray may be irradiated. The X-ray tube 12 is connected to an excitation X-ray tube control circuit (hereinafter referred to as “X-ray tube control circuit”) 13 to control supply power. Below the mounting portion 11b, when X-rays emitted from the X-ray tube 12 are irradiated onto the sample 1 to be measured, the fluorescence X emitted by exciting various elements contained in the sample 1 to be measured is emitted. A fluorescent X-ray measurement detector (hereinafter abbreviated as “fluorescent X-ray detector”) 14 is arranged so as to have a position and an angle at which a line can be detected. In the vicinity of the fluorescent X-ray detector 14, a γ-ray measurement detector (hereinafter abbreviated as “γ-ray detector”) 15 is arranged. A fluorescent X-ray signal processing circuit 16 is connected to the output terminal of the fluorescent X-ray detector 14. A γ-ray signal processing circuit 17 is connected to the output terminal of the γ-ray detector 15. An analysis control circuit 18 is connected to the output ends of the signal processing circuit 16 and the signal processing circuit 17.

Specifically, the fluorescent X-ray detector 14 is a Si-PIN detector using a Si semiconductor, an SDD (silicon drift detector), or the like. In order to obtain element information of the sample 1 to be measured, the X-ray fluorescence detector 14 obtains characteristic X-rays of elements contained in the sample as a spectrum of fluorescent X-rays when the sample 1 to be measured is irradiated with X-rays. Is. The energy region of the spectrum of the fluorescent X-ray detector 14 is approximately 1 keV to 50 keV.
Here, since the energy region of fluorescent X-rays is determined by the type of element to be measured, in the present embodiment, a trace amount of harmful heavy metals (for example, cadmium, lead, arsenic, chromium, mercury, etc.) contained in the toxic substance is used. In order to be able to be analyzed satisfactorily, a somewhat wider range of harmful heavy metals is selected to be approximately 1 keV to 50 keV as the range that can be analyzed.
As another example of the fluorescent X-ray detector 14, a detector other than Si, for example, a detector having CdTe, Ge, HgI2 or the like as a substrate may be used.

On the other hand, the energy region of γ rays emitted from the radioactive substance is approximately 50 keV to 1.5 MeV. The Si semiconductor has a very low detection efficiency (0.1% or less) with respect to the energy in this region, so it cannot be used practically.
Therefore, as the γ-ray detector 15, a combination of a solid scintillator and a semiconductor element, or a detector dedicated to γ rays combining a solid scintillator and a photomultiplier tube is used.
Here, since the energy region of γ-rays is determined by the nuclide of the radioactive substance to be measured, in this embodiment, a small amount of nuclide (e.g., potassium, cesium, etc.) of the nuclide (the element is K-39 out of K) , K-40, K-41, and / or Cs-133, Cs-134, Cs-135, Cs-137, etc. in which the element is Cs) I choose about 1.5MeV.
As another example of the γ-ray detector 15, a combination of a scintillator such as CsI or NaI and a photomultiplier tube or a photodiode, or a material such as Ge or CdTe may be used directly.

The signal processing circuit 16 and the signal processing circuit 17 are either an ASP (analog signal processing circuit) composed of an amplifier, a shaping amplifier, an AD converter, a memory, or the like, or a DSP (sample that directly samples the output from the amplifier and processes it by the AD converter. Any one of digital signal processing circuits) is used.
The analysis control circuit 18 temporarily stores sampling values (digital values) sequentially given from the signal processing circuit 16 and the signal processing circuit 17 on the basis of a command from a CPU 21 included in the measurement personal computer 20 described later, and the personal computer 20 The power supplied to the X-ray tube control circuit 13 is controlled on the basis of the control data given from. Details of the analysis control circuit 18 will be described later with reference to FIG.

  The measurement personal computer 20 calculates and processes the detection data from the signal processing circuit 16 and the signal processing circuit 17 to determine the qualitative / quantitative analysis of the elements contained in the substance to be measured and the nuclide and content of the contained radioactive substance. It is. It is also used for inputting various measurement conditions and outputting necessary information. The personal computer 20 is used by installing a program recorded in a dedicated CD-ROM or the like in an internal memory (22 shown in FIG. 3 described later) on a commercially available personal computer. The detailed configuration of the personal computer 20 will be described later with reference to FIG.

  Next, the principle (or outline) of the present invention will be described with reference to FIG. When X-rays emitted from the X-ray tube 12 irradiate the sample 1 to be measured, fluorescent X-rays specific to elements contained in the sample 1 to be measured are excited. As a result, elemental fluorescent X-rays are emitted from the sample 1 to be measured. This fluorescent X-ray is detected by the fluorescent X-ray detector 14, subjected to signal processing (sampling and digitization) by the signal processing circuit 16, and taken into the personal computer 20 through the analysis control circuit 18. The personal computer 20 extracts a fluorescent X-ray spectrum corresponding to an element contained in the sample 1 to be measured by performing arithmetic processing. By analyzing this spectrum in the personal computer 20, analysis and quantification (how much the specified element is contained) of the qualitative (what element is) of the element contained in the sample 1 to be measured Is done.

On the other hand, when a radioactive substance is contained in the sample 1 to be measured, γ rays are emitted from the radioactive substance itself. Since this γ-ray has a large energy, the fluorescent X-ray detector 14 usually has a very low detection efficiency. In order to compensate for this and detect γ-rays emitted from radioactive materials with high efficiency, a γ-ray detector 15 is used.
The γ-rays emitted from the radioactive substance are detected by the γ-ray detector 15, subjected to signal processing (sampling and digitization) through the signal processing circuit 17, and extracted as a γ-ray spectrum by the personal computer 20 through the analysis control circuit 18. Is done. By calculating this spectrum in a personal computer, the nuclide of the radioactive substance contained in the sample 1 to be measured and its content are analyzed.

Next, detailed configurations of the analysis control circuit 18 and the measurement personal computer 20 will be described with reference to FIG.
The analysis control circuit 18 includes a CPU 181, a memory 182 such as a RAM, a control register circuit 183, and interfaces 184 and 185. The memory 182 includes a storage area 182a and a storage area 182b. The storage area 182a is used as a fluorescent X-ray detection data storage area for storing the detection output of the fluorescent X-ray detector 14 as a sampling value (digital value). The storage area 182b is used as a γ-ray detection data storage area for storing the detection output of the γ-ray detector 15 as a sampling value (digital value). Each storage area 182a, 182b sequentially stores the respective sampling values in a first-in first-out manner.

  The control register circuit 183 temporarily stores control information (applied voltage and current data) from the personal computer 20 and supplies it to the X-ray tube control circuit 13. In response to this, the X-ray tube control circuit 13 controls the power (applied voltage, current) supplied to the X-ray tube 12 to control the energy of the generated X-ray. The interface 184 controls input and output so that inputs from the signal processing circuits 16 and 17 are given to the memory 182 and control data temporarily stored in the control register circuit 183 is given to the X-ray tube control circuit 13. To do. The interface 185 inputs / outputs the detection data stored in the storage areas 182a and 182b of the memory 182 to the personal computer 20 and the control data supplied from the personal computer 20 to the control register circuit 183. To control.

  The measurement personal computer 20 includes a CPU 21, a program memory 22 for storing a processing program, a memory 23 such as a RAM, and an interface 24. When the fluorescent X-ray analyzer is first used, a processing program recorded in an external storage medium such as a CD-ROM or DVD is installed in the memory 22. Similarly, in the table storage area 23b of the memory 23, elemental and nuclear spectral energy values recorded in an external storage medium such as a CD-ROM or DVD are preset and registered.

The memory 23 has a storage area 23a and a storage area 23b. The storage area 23a is used as a working RAM. The storage area 23b is used as a table storage area, and includes an element table 23b1 for specifying elements and a nuclide table 23b2 for specifying nuclides.
The element table 23b1 registers and stores in advance the spectral energy values obtained by measuring a known sample for each element that can be analyzed by the X-ray fluorescence analyzer of the present invention. For example, the purpose of the X-ray fluorescence spectrometer of the present invention is to analyze and measure trace amounts of harmful heavy metals (cadmium, lead, arsenic, chromium, mercury, etc.) and radioactive substances (potassium, cesium, etc.) contained in harmful substances. If so, for each of these elements (Cd, Pb, As, Cr, Hg, K, Cs, etc.), a spectral energy value (value of Kab, Kα, Kβ, etc .; unit “eV”) is set and registered ( Or memorized).
On the other hand, the nuclide table 23b2 is used to specify nuclides (elements K-39, K-40, K-41, and / or elements of K) in order to specify nuclides among elements (K, Cs, etc.) of radioactive materials. For each Cs-Cs-133, Cs-134, Cs-135, Cs-137, etc.), a spectral energy value (eV) obtained by measuring a known sample is set and registered (stored).

In addition, the element table 23b1 registers fluorescent X-ray intensity for each element obtained by measurement based on a known element, and conversion data for obtaining the content for each element from the fluorescent X-ray intensity. Yes. For example, the conversion data for obtaining the content for each element may be a calibration curve represented by a calculation formula or a content value for each fluorescent X-ray intensity for each predetermined unit.
On the other hand, in the nuclide table 23b2, the γ-ray intensity of the nuclide obtained by measurement based on the nuclide of the known radioactive substance and the conversion data for obtaining the content of the nuclide from the γ-ray intensity are registered. ing. For example, the conversion data for obtaining the content of the nuclear type may be a calibration curve represented by a calculation formula or a digital value of the content for each γ-ray intensity for each predetermined unit.

The CPU 21 extracts a fluorescent X-ray spectrum based on a program stored in the memory 22, specifies an element contained in the sample 1 to be measured based on the spectral energy value for each element in the element table 23 b 1, and X-rays The content of the element specified based on the strength is obtained. Further, the CPU 21 specifies the nuclide of the radioactive substance contained in the sample 1 to be measured based on the nuclide type spectrum energy value in the nuclide table 23b2, and calculates the content of the nuclide specified based on the γ-ray intensity. Process.
More specifically, the CPU 21 calculates the content for each analyzed element based on the X-ray intensity for each element and the calibration curve corresponding to the element, and calculates the γ-ray intensity for each nuclear type and the nuclide. Based on the corresponding calibration curve, the content of the analyzed nuclear type is calculated.

  A keyboard 25 and a display 26 are connected to the interface 24. The interface 24 controls input / output with the interface 185, the keyboard 25, and the display 26.

  Next, with reference to FIGS. 1 to 5, the detailed operation of this embodiment will be described along the flowchart of FIG.

First, prior to analysis / measurement of elements and radioactive substances, a sample 1 to be measured that is an object of analysis / measurement is collected. As shown in FIG. 4, the sample to be analyzed and measured includes the original ground surface portion (lower hatched portion) 1a and the deposited portion of radioactive material scattered by a nuclear accident at a nuclear power plant ( The upper layer, that is, the layer piled on the ground surface 1 a) 1 b is collected and placed in the sample container 2.
For sampling, a large number of points within a predetermined distance from the accident point of the nuclear power plant where radioactive material is expected to be scattered are selected. Then, by measuring the amount of radiation using a survey meter or the like, it is confirmed that the radioactive substance is contained, and the one within a level range that does not greatly affect the human body is selected.

  Here, when the sample is collected, the reason for collecting both the original surface surface portion (lower layer portion) 1a and the deposited layer portion (upper layer portion) 1b is that the radioactive material contained in the deposited layer portion 1b is Because it was scattered due to an accident at a nuclear power plant and the same element is a different nuclide, the elements contained in the original surface surface portion 1a are also qualitatively and quantitatively collected, and samples of both layers are collected. This is because it is necessary to analyze and measure.

The measurer opens the lid 11a of the main body 10, places the sample container 2 containing the sample 1 to be measured at a predetermined position on the placement portion 11b, and closes the lid 11a. Thereafter, the measurer operates the keyboard 25 (or mouse) to instruct the start of analysis / measurement.
In response to this, the CPU 21 starts the analysis processing operation of the flowchart shown in FIG. 5 based on the processing program stored in the memory 22. In step (abbreviated as “S” in FIG. 5) 1, it is determined whether or not the lid 11a is closed. If it is determined that the lid 11a is open, in step 2, a message for instructing to close the lid 11a is displayed on the display 26, and then it waits until the lid 11a is closed.

If it is determined that the lid 11a is closed, the lid 11a is locked in step 3 to prevent the lid 11a from being accidentally opened during the analysis.
In step 4, the CPU 21 reads data on the applied voltage and current of the X-ray tube 12 from the memory 22 and temporarily stores it in the control register circuit 183. Based on the applied voltage and current value data, the X-ray tube control circuit 13 controls the applied voltage and current (resulting in power) supplied to the X-ray tube 12. In response to this, the X-ray tube 12 generates X-rays and irradiates the sample 1 to be measured. At this time, fluorescent X-rays specific to the type of element contained in the sample are excited from the sample 1 to be measured. This fluorescent X-ray is detected by the fluorescent X-ray detector 14.
In step 5, the signal is processed by the signal processing circuit 16 and converted into a digital value, which is sequentially written and stored in the storage area 182a.
In step 4 described above, the applied voltage value and current value (or power) supplied to the X-ray tube 12 may be changed as necessary depending on the type of element to be detected.

At substantially the same time, the γ-ray detector 15 detects γ-rays emitted directly from the sample 1 to be measured. In step 6, the detected analog value of the γ-ray is signal-processed by the signal processing circuit 17 and converted into a digital value, which is sequentially written and stored in the storage area 182 b.
In step 7, it is determined whether or not a predetermined measurement time has elapsed, and the processes of steps 4 to 6 are repeated until the predetermined measurement time has elapsed. In this way, the fluorescent X-ray sampling data detected at a relatively short predetermined time (sampling period) is accumulated and stored (or temporarily stored) in the storage area 182a, and γ detected at every predetermined time. The sampling data of the line is accumulated and stored (or temporarily stored) in the storage area 182b.
When it is determined that the predetermined measurement time has elapsed, in step 8, the power supply to the X-ray tube 12 is stopped.
Note that the processing in step 6 (processing for accumulating the output of the γ-ray detector 15 in the storage area 182b) may be performed after the power supply to the X-ray tube 12 is stopped.

In subsequent step 9, the fluorescent X-ray detection data (accumulated data) temporarily stored in the storage area 182a of the memory 182 and the γ-ray detection data (accumulated data) temporarily stored in the storage area 182b are transferred to the interface 185 and The data is transferred to the working RAM 23a via the interface 24 and temporarily stored.
In step 10, an element identification (or analysis) process included in the sample 1 to be measured is performed. This element specifying process is included in the sample 1 to be measured while sequentially comparing and collating the accumulated X-ray fluorescence data temporarily stored in the working RAM 23a with the spectral energy values for each element registered in the element table 23b1. This is a process for identifying what elements are to be detected.
In step 11, the content of the identified element is determined. The processing for obtaining the content of each element is performed by measuring the X-ray intensity for each identified element. Specifically, the content of each element is calculated by performing arithmetic processing based on the measured X-ray intensity for each element and the calibration curve for each element.
Note that when a small amount of element is detected in a configuration in which the γ-ray detector and the X-ray detector are arranged close to each other, accurate X-ray fluorescence analysis may be difficult. Before the background correction processing may be performed as necessary. Thereby, errors caused by the background can be reduced.

Thereafter, in step 12, it is determined whether or not the specified element contains a radioactive substance. If it is determined that no radioactive substance is contained, the process proceeds to step 13 where the specified element and its content are displayed on the display 26.
Thereafter, in step 14, the lid 11a is unlocked, and the sample 1 to be measured can be taken out. At this time, a message instructing removal or replacement of the sample 1 to be measured may be displayed on the display 26. In this case, since no radioactive substance is contained, the process for determining the nuclide and the process for obtaining the content thereof are omitted, and the analysis / measurement processing time can be shortened.
Note that the operation of the above-mentioned “Measurement process of content of specified element” in Step 11 is performed after it is determined in Step 12 that a radioactive substance is not included, and Step 13 (Content of specified element is included). It may be performed before the quantity display process.

  On the other hand, if it is determined in step 12 described above that a radioactive substance is contained, the process proceeds to step 15 where a radionuclide identification process is performed. This nuclide identification process is included in the sample 1 to be measured while sequentially comparing and collating the accumulated data of γ rays temporarily stored in the working RAM 23a and the spectral energy values of the nuclide types registered in the nuclide table 23b2. Radioactive nuclides are identified sequentially.

  In the subsequent step 16, a process for determining the content of the specified nuclide is performed. The process for obtaining the nuclide content is performed by measuring the γ-ray intensity for the specified nuclide type. Specifically, the nuclear type content of the radioactive substance is calculated by performing arithmetic processing based on the measured gamma ray intensity of the nuclear type and the calibration curve of the nuclear type.

In step 17, the specified nuclide and content are displayed. At this time, the content of the element specified in step 10 and the element obtained in step 11 are displayed on the display 26 together. Even if it is an element of a radioactive substance, if it is determined that the nuclide is K-40 or Cs-137 having a long half-life, a warning may be displayed indicating that it is highly harmful.
Thereafter, the lid 11a in step 14 is unlocked, and the analysis / measurement process ends.

  As described above, the process of determining the content and content of the nuclide of the element and / or radioactive substance contained in the sample 1 to be measured is performed substantially simultaneously. Then, fluorescent X-ray detection and γ-ray detection are performed at the same time, and then the element is specified. If the specified element contains a radioactive substance, its nuclide is specified, so two separate analyzes are performed. Compared with the case of analyzing and measuring using an apparatus, the overall analysis / measurement time can be shortened and the measurement can be performed efficiently.

(Example 2)
By the way, in Example 1 of FIG. 2, the example which has arrange | positioned the gamma-ray detector 15 below the mounting part 11b is shown. This embodiment is suitable for detecting whether radioactive material is present in a layer close to the original ground surface.
However, for the purpose of detecting radioactive material scattered in the surrounding area due to a nuclear accident at a nuclear power plant, the position of the γ-ray detector 15 is arranged so that the deposited layer portion (upper layer portion) 1b can be easily measured. Is preferably selected as a position above the sample 1 to be measured (that is, a position within the storage chamber 11c and above the position on the mounting portion 11b on which the sample 1 to be measured is placed).
Therefore, in the embodiment of FIG. 6, the γ-ray detector 15 is attached at a position above the sample 1 to be measured. The other configuration is the same as that of the embodiment of FIG.

  In Example 2 of FIG. 6, for example, when analyzing radioactive substances (K, Cs, etc.) in the soil, if the sample 1 to be measured is collected in a cylindrical shape, the soil of the lower layer portion 1a is obtained by fluorescent X-ray analysis. Its content is determined and information on naturally occurring radioactive materials is obtained. On the other hand, the degree of radiation contamination can be determined by measuring K radiation with gamma rays in the upper layer portion 1b of the soil. By using both of these data, it is possible to measure separately from those derived from nature and those caused by radiation contamination.

(Example 3)
In the embodiment of FIG. 7, the arrangement position of the γ-ray detector 15 is the side surface of the mounting portion 11 b on which the sample 1 to be measured is placed. In the embodiment of FIG. 7, the nuclide can be accurately identified and contained in the portion between the upper layer portion and the lower layer portion of the sample 1 to be measured.

As another embodiment, when it can be allowed to take a long time for analysis and measurement, the fluorescent X-ray detector and the γ-ray detector are operated independently to detect fluorescent X-rays and γ-rays. May be performed independently and separately.
More specifically, the fluorescent X-ray detector and the γ-ray detector may be operated in a time-sharing manner to detect fluorescent X-rays and detect and analyze γ-rays sequentially (each separately). In that case, since the work for putting the sample 1 into and out of the sample chamber 11c only needs to be performed once, there is an advantage that the measurement time can be shortened as compared with the case of analyzing and measuring using a separate analyzer. Further, there is an advantage that the maximum power consumption can be reduced as compared with the case where both fluorescent X-rays and γ-rays are detected and analyzed simultaneously.

Example 4
In addition, using a detector that can detect both the energy region for the measurement of the X-ray region and the measurement of the γ-ray region, an analysis process is performed so as to obtain a fluorescent X-ray spectrum and a γ-ray spectrum at the same time. Also good.

(Example 5)
In the above-described embodiment, both the fluorescent X-ray detector 14 and the γ-ray detector 15 are used to specify an element and measure the content of each element, and when a radioactive substance is included, specify a nuclide. However, the technical idea of this invention is also applicable to γ-ray analyzers (or radioactive material analyzers) that determine the radionuclide species and measure the nuclear type content. it can.
In the case of a γ-ray analyzer, the excitation X-ray tube 12, X-ray tube control circuit 13, fluorescent X-ray detector 14, and signal processing circuit 16 related to the identification of elements by fluorescent X-rays are included in the configuration of FIG. 2. Omitted. The analysis process is achieved only by other processes in which the processes of S4, S5, S8, S10, S11, and S13 are omitted in the flowchart of FIG.

  In the present invention, the element contained in the sample to be measured can be specified and its content can be obtained, and when the specified element contains a radioactive substance, the nuclide can be specified and its content can be obtained. Industrially useful as a fluorescent X-ray analyzer with a radioactive substance detection function, which is useful for analysis of soil or the like that may contain radioactive substances.

Appendix

(1) A placement unit for placing a sample to be measured;
A sample chamber in which the periphery is covered with a shielding member and stores the mounting portion and the sample to be measured,
Equipped with a γ-ray detector for measuring a γ-ray region (50 keV to 1.5 MeV) of a sample to be measured placed on the mounting unit, and an analysis processing means for obtaining a γ-ray spectrum by operating the γ-ray detector. ,
The analysis processing means specifies the nuclide of the radioactive substance contained in the sample to be measured based on the spectrum of the γ-ray detected by the γ-ray detector, and obtains the content of the specified nuclide. Analysis equipment.

(2) The γ-ray analyzer according to (1), wherein the γ-ray detector is disposed above the sample to be measured placed on the placement unit.

(3) The γ-ray analyzer according to (1), wherein the γ-ray detector is disposed on a side surface of the sample to be measured placed on the placement unit.

(4) Analytical processing means
Includes a table in which the γ-ray spectrum data and intensity data are registered in the nuclear type of radioactive material to be measured,
The radioactivity nuclide contained in the sample to be measured is identified by comparing and comparing the gamma ray spectrum contained in the sample to be measured and detected by the gamma ray detector and the gamma ray spectrum registered in the table, and The content of the nuclide identified based on the intensity of the γ-ray detected by the γ-ray detector and the conversion data registered in the table is obtained, according to any one of (1) to (3) Gamma ray analyzer.

(5) The γ-ray analyzer is a storage unit for accumulating and storing a spectrum value of γ-rays sequentially detected and sampled by a γ-ray detector every unit time and accumulated over a predetermined long time with a change in time. Further comprising
Analysis processing means
Including the data table in which the γ-ray spectrum data and conversion data are registered in advance in the nuclear type of the radioactive material to be measured,
γ-ray spectral values at predetermined times sequentially detected by the γ-ray detector and stored in the cumulative storage unit are compared with the γ-ray spectral values registered in the data table and included in the sample to be measured. (1) characterized in that the nuclide of the radioactive material is specified, and the content of the specified nuclide is determined based on the intensity of the γ-ray detected by the γ-ray detector and the conversion data registered in the data table. Thru | or the gamma ray analyzer in any one of (3).

According to the γ-ray analyzer described in the above (1) to (3), a spectrum of γ-rays depending on the nuclide of the radioactive substance contained in the sample can be obtained, which is useful for specifying the nuclide of the radioactive substance. An analysis device is obtained.
In addition, according to the γ-ray analyzer described in the above (4) and (5), an analyzer that can determine the radionuclide nuclide contained in the sample and its content can be obtained.
Furthermore, the nuclide identification and its content can be analyzed and measured quickly and efficiently.
Such a γ-ray analyzer can identify the radionuclide nuclide contained in the sample to be measured and determine the content thereof, so that there is a concern about radioactive contamination (for example, crops such as rice and vegetables, milk, etc.) (Agricultural products such as agricultural products, seafood, etc.) and soil, etc., and is highly industrially useful as a gamma ray analyzer.

DESCRIPTION OF SYMBOLS 1 Sample to be measured 10 X-ray fluorescence analyzer main body 11 Housing 11a Lid 11b Placement part 11c Sample room 11d Equipment storage room 12 Fluorescent X-ray tube 13 X-ray tube control circuit 14 Fluorescent X-ray detector 15 γ-ray detector 16, 17 Signal Processing Circuit 18 Analysis Control Circuit 181 CPU
182 Memory 183 Control register circuit 184, 185 Interface 20 PC for measurement 21 CPU
22 Memory for processing program 23 RAM (memory)
23a Working RAM
23b Table storage area 23b1 Element table 23b2 Nuclide table 24 Interface 25 Keyboard 26 Display

Claims (11)

A fluorescent X-ray detector for measuring an X-ray region (1 keV to 50 keV);
γ-ray detector for measuring a γ-ray region (50 keV to 1.5 MeV), and analysis processing for operating the fluorescent X-ray detector and the γ-ray detector to obtain a fluorescent X-ray spectrum and a γ-ray spectrum A fluorescent X-ray analyzer provided with means.   2. The analysis processing unit according to claim 1, wherein the fluorescent X-ray detector and the γ-ray detector are simultaneously operated to obtain a fluorescent X-ray spectrum and a γ-ray spectrum simultaneously. X-ray fluorescence analyzer.   The analysis processing means operates the fluorescent X-ray detector and the γ-ray detector independently to obtain a fluorescent X-ray spectrum and a γ-ray spectrum separately. The fluorescent X-ray analyzer according to 1.   A detector capable of simultaneously measuring X-ray region (1 keV to 50 keV) and γ-ray region (50 keV to 1.5 MeV) is operated, and the detector is operated to obtain a fluorescent X-ray spectrum and a γ-ray spectrum. An X-ray fluorescence analyzer characterized by comprising analysis processing means for obtaining simultaneously.   The X-ray fluorescence analyzer includes a placement unit for placing a sample to be measured, a sample chamber for housing the placement unit and the sample to be measured, and an excitation X for X-ray fluorescence measurement that irradiates the sample to be measured with X-rays. The fluorescent X-ray analyzer according to any one of claims 1 to 3, further comprising a ray tube. The excitation X-ray tube for fluorescent X-ray measurement irradiates X-rays from below the mounting portion toward the sample to be measured,
The fluorescent X-ray analysis apparatus according to claim 5, wherein the fluorescent X-ray detector and the γ-ray detector are arranged below the mounting portion. The excitation X-ray tube for fluorescent X-ray measurement irradiates X-rays from below the mounting portion toward the sample to be measured,
The fluorescent X-ray detector is disposed below the placement unit,
The fluorescent X-ray analyzer according to claim 5, wherein the γ-ray detector is disposed above a sample to be measured placed on the mounting portion. The excitation X-ray tube for fluorescent X-ray measurement irradiates the sample to be measured from below the mounting portion,
The fluorescent X-ray detector is disposed below the placement unit,
The fluorescent X-ray analyzer according to claim 5, wherein the γ-ray detector is disposed on a side surface of the sample to be measured placed on the mounting portion. When the X-ray excited by the X-ray tube for fluorescent X-ray measurement is irradiated to the sample to be measured, the fluorescent X-ray detector has an element-specific fluorescence X generated by excitation of the element contained in the sample to be measured. Detect lines,
The γ-ray detector detects γ-rays emitted from the sample to be measured in connection with the detection of fluorescent X-rays by the fluorescent X-ray detector,
The analysis processing means specifies an element contained in a sample to be measured based on a fluorescent X-ray spectrum detected by the fluorescent X-ray detector and obtains the content of the specified element, and the γ-ray detector 9. The radionuclide nuclide contained in the sample to be measured is identified based on the spectrum of the gamma rays detected by the step, and the content of the identified nuclide is obtained. The described fluorescent X-ray analyzer. A placement unit for placing the sample to be measured, a sample chamber for storing the placement unit and the sample to be measured, and an excitation X for fluorescent X-ray measurement for irradiating the sample to be measured placed on the placement unit with X-rays In a fluorescent X-ray analyzer having a tube,
A fluorescent X-ray detector for measuring an X-ray region (1 keV to 50 keV);
A γ-ray detector for measuring a γ-ray region (50 keV to 1.5 MeV), and a power supplied to the excitation X-ray tube for fluorescent X-ray measurement are controlled, and the detection output of the fluorescent X-ray detector and the γ-ray Comprising analysis processing means for performing analysis processing based on the detection output of the detector;
The fluorescent X-ray detector detects fluorescent X-rays generated by excitation of elements contained in the sample to be measured when the sample to be measured is irradiated with X-rays excited by the excitation X-ray tube for fluorescent X-ray measurement And
The γ-ray detector detects γ-rays emitted from the measured sample itself in connection with the detection of the fluorescent X-rays by the fluorescent X-ray detector,
The analysis processing means specifies an element contained in a sample to be measured based on a fluorescent X-ray spectrum detected by the fluorescent X-ray detector and obtains the content of the specified element, and the γ-ray detector A fluorescent X-ray analyzer characterized in that the nuclide of a radioactive substance contained in a sample to be measured is specified based on the spectrum of γ rays detected by, and the content of the specified nuclide is obtained.   The analysis processing means determines whether or not the specified element is a radioactive substance, and after determining that the element is a radioactive substance, performs a process of specifying the nuclide of the radioactive substance and obtaining the content of the specified nuclide. The fluorescent X-ray analyzer according to claim 9 or 10, wherein

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