X-ray fluorescence analysis system, information storage medium, liquid sample cell used in the X-ray fluorescence analysis system, and X-ray fluorescence analysis program

Abstract

The impact of sedimentation of precipitation components on measurement results is reduced while suppressing increases in manufacturing costs. [Solution] An X-ray fluorescence analysis system having a rotation mechanism that rotates a sample cell and a speed control unit that controls the rotation speed of the rotation mechanism, and operates in operating modes including: a non-stirring measurement mode in which the detector performs measurements while the rotation mechanism rotates at a constant speed under the control of the speed control unit; and a stirring measurement mode that includes a stirring period in which the speed control unit stirs the liquid sample by rotating the rotation mechanism at a varying rotation speed, and a post-stirring measurement period in which the detector performs measurements after the liquid sample has been stirred. The liquid sample cell contains the liquid sample, and includes a portion whose cross section of the containing space parallel to the bottom surface is not a circle centered on the rotation axis of the sample cell.

Description

[Technical Field]

[0001] The present invention relates to an X-ray fluorescence analysis system, an information storage medium, a liquid sample cell used in the X-ray fluorescence analysis system, and an X-ray fluorescence analysis program. [Background technology]

[0002] X-ray fluorescence analyzers are known as devices for measuring the elements contained in samples and their concentrations, and can analyze both solid and liquid samples.

[0003] When analyzing solid samples, the surface roughness of the solid sample can make the analysis inaccurate. To reduce the effects of surface roughness, there are X-ray fluorescence analyzers that measure the sample while rotating it in-plane.

[0004] When analyzing a liquid sample, sedimentary components in the sample may settle, causing the measurement results to change over time. To prevent sedimentary components from settling during measurement, some X-ray fluorescence analyzers are equipped with a stirring blade inside the sample cell that rotates within the sample cell (see Patent Documents 1 and 2 below).

[0005] There are also X-ray diffractometers and spectrophotometers that perform measurements after rotating a sample holder filled with a liquid sample (see Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 52-046791 [Patent Document 2] Special Publication No. 53-009558 [Patent Document 3] Japanese Patent Application Publication No. 10-38772 [Patent Document 4] Japanese Patent Application Laid-Open No. 2009-128043 Summary of the Invention [Problem to be solved by the invention]

[0007] When a stirring blade is provided inside the sample cell as in Patent Documents 1 and 2, a separate mechanism for rotating the stirring blade is required, which increases manufacturing costs. In particular, when the stirring blade is rotated using magnetic force, the ferromagnetic material contained in the stirring blade may affect the measurement results.

[0008] Even if the sample cell itself is configured to rotate, there is a risk that the liquid sample may not be sufficiently stirred inside a cylindrical sample cell such as those disclosed in Patent Documents 3 and 4.

[0009] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide an X-ray fluorescence analysis system, an information storage medium, a liquid sample cell for use in an X-ray fluorescence analysis system, and an X-ray fluorescence analysis program that can reduce the impact of precipitation of sedimentary components on measurement results by sufficiently stirring a liquid sample, while suppressing increases in manufacturing costs by using a rotation mechanism to reduce the impact of surface roughness on the solid sample. [Means for solving the problem]

[0010] (1) An X-ray fluorescence analysis system according to one aspect of the present disclosure includes a sample stage on which a sample cell having a storage space for storing a sample is placed and which has an opening through which a bottom surface of the sample cell is exposed, a rotation mechanism for rotating the sample cell placed on the sample stage, an X-ray source for irradiating the bottom surface of the sample stage with X-rays from below the sample stage through the opening of the sample stage, a detector for measuring the intensity of fluorescent X-rays generated from the sample, and a speed control unit for controlling the rotation speed of the rotation mechanism, wherein the sample cell is placed on the sample stage and has a storage space for storing a sample, and The device comprises a liquid sample cell in which the cross section of the storage space parallel to the bottom surface includes a portion that is not a circle centered on the rotation axis of the sample cell, and a solid sample cell in which a solid sample is stored, and is characterized by operating in operating modes including: a non-stirring measurement mode in which the detector performs measurement while the rotation mechanism rotates at a constant rotation speed under the control of the speed control unit; and a stirring measurement mode including a stirring period in which the speed control unit stirs the liquid sample by rotating the rotation mechanism at a varying rotation speed, and a post-stirring measurement period in which the detector performs measurement after the liquid sample has been stirred.

[0011] (2) In another aspect of the X-ray fluorescence analysis system of the present disclosure, the sample stage is capable of supporting the liquid sample cell and the solid sample cell, and in the non-stirring measurement mode, the solid sample cell is placed on the sample stage, and in the stirring measurement mode, the liquid sample cell is placed on the sample stage.

[0012] (3) In another aspect of the X-ray fluorescence analysis system of the present disclosure, the storage space of the liquid sample cell has a substantially cylindrical shape, and the liquid sample cell has one or more fins having predetermined lengths in the radial direction and the rotation axis direction of the storage space.

[0013] (4) In another aspect of the X-ray fluorescence analysis system of the present disclosure, the liquid sample cell has a cylindrical portion with an opening at the top and a lid portion that fits into the opening, and the fin is formed integrally with the lid portion.

[0014] (5) In another aspect of the X-ray fluorescence analysis system of the present disclosure, the liquid sample cell has a cylindrical portion with an open top, and the fin is formed integrally with the cylindrical portion.

[0015] (6) In another aspect of the X-ray fluorescence analysis system of the present disclosure, the liquid sample cell has a cylindrical portion with an open top, the cylindrical portion and the fins are formed separately, and the fins are fitted into the cylindrical portion.

[0016] (7) In a fluorescent X-ray analysis system according to another aspect of the present disclosure, the cylindrical portion and the fins are formed of the same material.

[0017] (8) A fluorescent X-ray analysis system according to another aspect of the present disclosure further includes the liquid sample cell.

[0018] (9) In a fluorescent X-ray analysis system according to another aspect of the present disclosure, the speed control unit instructs the rotation mechanism to discontinuously change the rotation speed during the stirring period.

[0019] (10) In another aspect of the X-ray fluorescence analysis system of the present disclosure, the speed control unit is characterized in that, during the stirring period, the speed control unit instructs the rotation mechanism to rotate in a forward direction for a predetermined time, and then instructs the rotation mechanism to rotate in a reverse direction.

[0020] (11) In a fluorescent X-ray analysis system according to another aspect of the present disclosure, the speed control unit issues an instruction to stop the rotation mechanism during the post-mixing measurement period.

[0021] (12) In a fluorescent X-ray analysis system according to another aspect of the present disclosure, the speed control unit issues an instruction to rotate the rotation mechanism during the post-mixing measurement period.

[0022] (13) In another aspect of the X-ray fluorescence analysis system of the present disclosure, the speed control unit is characterized in that, during the post-mixing measurement period, the speed control unit instructs the rotation mechanism to rotate in a forward direction for a predetermined time, and then instructs the rotation mechanism to rotate in a reverse direction.

[0023] (14) An information storage medium according to one aspect of the present disclosure is a non-transitory computer-readable information storage medium storing an X-ray fluorescence analysis program executed by a computer used in an X-ray fluorescence analysis system, the X-ray fluorescence analysis system including: a sample stage on which a sample cell having a storage space for storing a sample is placed and which has an opening through which a bottom surface of the sample cell is exposed; a rotation mechanism for rotating the sample cell placed on the sample stage; an X-ray source for irradiating X-rays from below the sample stage through the opening of the sample stage to the bottom surface; a detector for measuring the intensity of fluorescent X-rays generated from the sample; and a speed control unit for controlling the rotation speed of the rotation mechanism. The sample cell includes a liquid sample cell in which a liquid sample is accommodated, and a cross section of the accommodation space parallel to the bottom surface includes a portion that is not a circle centered on the rotation axis of the sample cell, and a solid sample cell in which a solid sample is accommodated, and the fluorescent X-ray analysis program causes the computer to execute operating modes including: a non-stirring measurement mode in which the detector performs measurement while the rotation mechanism is rotating at a constant rotation speed under the control of the speed control unit; and a stirring measurement mode including a stirring period in which the speed control unit stirs the liquid sample by rotating the rotation mechanism at a varying rotation speed, and a post-stirring measurement period in which the detector performs measurement after the liquid sample has been stirred.

[0024] (15) In an information storage medium according to another aspect of the present disclosure, the stirring measurement mode alternately includes the stirring periods and the post-stirring measurement periods, and the fluorescent X-ray analysis program, when executing the stirring measurement mode, causes the computer to execute the following steps: measuring the intensity of the fluorescent X-rays by the detector during the nth post-stirring measurement period; measuring the intensity of the fluorescent X-rays by the detector during the (n+1)th post-stirring measurement period; and determining whether to set the (n+2)th stirring period based on the intensity of the fluorescent X-rays measured during the nth post-stirring measurement period and the intensity of the fluorescent X-rays measured during the (n+1)th post-stirring measurement period.

[0025] (16) In another aspect of the information storage medium of the present disclosure, the determining step is characterized in that the (n+2)th stirring period is set when the difference or ratio between the intensity of the fluorescent X-rays measured during the nth post-stirring measurement period and the intensity of the fluorescent X-rays measured during the (n+1)th post-stirring measurement period is greater than a predetermined value.

[0026] (17) A liquid sample cell according to one aspect of the present disclosure is characterized in that the storage space of the liquid sample cell has a substantially cylindrical shape, and the liquid sample cell has one or more fins having predetermined lengths in the radial and axial directions of the storage space.

[0027] (18) A liquid sample cell according to another aspect of the present disclosure has a cylindrical portion with an open top surface, The cylindrical portion and the fins are formed separately, and the fins are fitted to the cylindrical portion.

[0028] (19) In a liquid sample cell according to another aspect of the present disclosure, the cylindrical portion and the fins are formed of the same material.

[0029] (20) An X-ray fluorescence analysis program according to one aspect of the present disclosure is an X-ray fluorescence analysis program executed by a computer for use in an X-ray fluorescence analysis system having: a sample stage on which a sample cell having a storage space for storing a sample is placed and which has an opening through which a bottom surface of the sample cell is exposed; a rotation mechanism for rotating the sample cell placed on the sample stage; an X-ray source for irradiating X-rays from below the sample stage through the opening of the sample stage onto the bottom surface; a detector for measuring the intensity of the X-ray fluorescence generated from the sample; and a speed control unit for controlling the rotation speed of the rotation mechanism, wherein the sample cell is: The device is characterized in that it causes the computer to execute operating modes including: a liquid sample cell in which a liquid sample is accommodated, and a solid sample cell in which a solid sample is accommodated, the cross section of the accommodation space parallel to the lower surface including a portion that is not a circle centered on the rotation axis of the sample cell; and a non-stirring measurement mode in which the detector performs measurement while the rotation mechanism is rotating at a constant rotation speed under the control of the speed control unit; and a stirring measurement mode including a stirring period in which the liquid sample is stirred by the speed control unit rotating the rotation mechanism at a variable rotation speed, and a post-stirring measurement period in which the detector performs measurement after the liquid sample has been stirred. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a diagram showing an outline of an X-ray fluorescence analysis system. [Figure 2] FIG. 1 is a bird's-eye view of the sample stage and the rotation mechanism. [Figure 3] FIG. 1 is a diagram illustrating a hardware configuration of an information processing device. [Figure 4] FIG. 2 is a functional block diagram of a calculation unit. [Figure 5] 1A and 1B are a top view and a cross-sectional view of a liquid sample cell. [Figure 6] 1A and 1B are a top view and a cross-sectional view of a solid sample cell. [Figure 7] 4 is a time chart for explaining the first embodiment. [Figure 8] 10 is a flowchart for explaining a second embodiment. [Figure 9]1A and 1B are a top view and a cross-sectional view of a liquid sample cell according to Modification 1. [Figure 10] 10A and 10B are a top view and a cross-sectional view of a liquid sample cell according to Modification 2. [Figure 11] 10A and 10B are a top view and a cross-sectional view of a liquid sample cell according to Modification 3. [Figure 12] 10A and 10B are a top view and a cross-sectional view of a sample cell according to Modification 4.

[0031] A preferred embodiment for carrying out the present invention (hereinafter referred to as an embodiment) will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing a cross section of an X-ray fluorescence analysis system 100 according to this embodiment. As shown in Fig. 1, the X-ray fluorescence analysis system 100 includes a sample stage 102, a rotation mechanism 104, an X-ray source 106, a detector 108, and an information processing device 300 (see Fig. 3).

[0032] The X-ray source 106 irradiates the lower surface of the sample stage 102 with X-rays from below through an opening in the sample stage 102. Specifically, the X-ray source 106 is disposed below the sample stage 102. An opening is provided in the sample stage 102, and primary X-rays are irradiated from below the sample stage 102 toward the opening.

[0033] The sample stage 102 has an opening on which a sample cell is placed, exposing the bottom surface of the sample cell. Specifically, for example, FIG. 2 is a bird's-eye view of the sample stage 102 and the rotation mechanism 104 arranged on the sample stage 102. As shown in FIG. 2, the sample stage 102 has an opening at the position where the sample cell is placed. The opening is provided on the path of the primary X-rays emitted by the X-ray source 106. The sample stage 102 according to this embodiment is capable of placing a liquid sample cell 500 and a solid sample cell 600. Note that the sample stage 102 is only required to be capable of placing the solid sample cell 600, and does not necessarily have to be capable of placing the liquid sample cell 500.

[0034] The rotation mechanism 104 rotates the sample cell placed on the sample stage 102. Specifically, the rotation mechanism 104 includes, for example, an actuator such as a motor and a ring-shaped member provided at the opening of the sample stage 102. The actuator rotates the ring-shaped member via a belt (not shown), causing the rotation mechanism 104 to rotate the sample cell placed on the sample stage 102 within the XY plane. Note that, hereinafter, a plane horizontal to the surface of the sample stage 102 is defined as the XY plane (the rightward direction in FIG. 1 is the X direction, and the forward direction is the Y direction), and a direction perpendicular to the XY plane (upward direction in FIG. 1) is defined as the Z direction.

[0035] The detector 108 measures the intensity of the fluorescent X-rays emitted from the sample. Specifically, the detector 108 is, for example, a proportional counter. The detector 108 is placed at a position where the fluorescent X-rays are incident, detects the fluorescent X-rays, and outputs a pulse signal. The output pulse signal is input to a counter, which counts the pulse signals and obtains the counted pulse signals as the intensity of the fluorescent X-rays. Data representing the intensity of the fluorescent X-rays counted by the counter is transmitted to the information processing device 300.

[0036] A spectroscopic element may be provided to disperse fluorescent X-rays of a predetermined wavelength emitted from the sample. The spectroscopic element is disposed on the path of the primary X-rays or the path of the fluorescent X-rays. A spectroscopic element and detector 108 may be provided for each element to be analyzed, or a set of spectroscopic element and detector 108 may be configured to rotate. When a set of spectroscopic element and detector 108 is rotated, a mechanism (goniometer) for rotating the spectroscopic element and detector 108 is provided.

[0037] The information processing device 300 controls the operations of the rotation mechanism 104 and the X-ray source 106, analyzes the sample based on the output of the counter, and displays and outputs the analysis results. Specifically, for example, the information processing device 300 is a personal computer, and includes a calculation unit 302, a storage unit 304, a display unit 306, an input / output unit 308, and an internal bus 310, as shown in FIG.

[0038] The calculation unit 302 is a CPU, MPU, or the like, and operates according to a program stored in the storage unit 304. FIG. 4 is a functional block diagram of the calculation unit 302. Functionally, the calculation unit 302 includes an analysis unit 402 and a speed control unit 404. The analysis unit 402 controls the operation of the rotation mechanism 104 and the X-ray source 106, and analyzes the sample based on the output of the counter. The speed control unit 404 controls the rotation speed of the rotation mechanism 104. The calculation unit 302 executes the fluorescent X-ray analysis program stored in the storage unit 304, causing the analysis unit 402 and the speed control unit 404 to perform the above functions. Details of the operation of the speed control unit 404 will be described later.

[0039] The storage unit 304 is a non-transitory computer-readable information storage medium that stores an X-ray fluorescence analysis program executed by a computer used in the X-ray fluorescence analysis system 100. Specifically, the storage unit 304 is, for example, an information storage medium such as a ROM, a RAM, or a hard disk. The storage unit 304 stores the X-ray fluorescence analysis program executed by the calculation unit 302. The storage unit 304 also operates as, for example, a work memory for the calculation unit 302. The X-ray fluorescence analysis program causes the information processing device 300 to execute operation modes including a non-stirring measurement mode (described later) and a stirring measurement mode (described later).

[0040] The display unit 306 is, for example, a liquid crystal display or an organic EL display, and displays information according to instructions from the calculation unit 302.

[0041] The input / output unit 308 is a keyboard or mouse that accepts user input. The input / output unit 308 is also a communication interface such as a network interface or a USB port that communicates with other computers via wired or wireless communication. The calculation unit 302, the storage unit 304, the display unit 306, and the input / output unit 308 are connected by an internal bus 310.

[0042] Although the liquid sample cell 500 and the solid sample cell 600 are not included in the X-ray fluorescence analysis system 100 in the above description, the X-ray fluorescence analysis system 100 may include the liquid sample cell 500 and / or the solid sample cell 600.

[0043] Next, the sample cell according to this embodiment will be described. The sample cells used in this embodiment include a liquid sample cell 500 and a solid sample cell 600. Fig. 5 shows a top view and a cross-sectional view of the liquid sample cell 500 in which a liquid sample is accommodated. Fig. 6 shows a top view and a cross-sectional view of the solid sample cell 600 in which a solid sample is accommodated. Both the liquid sample cell 500 and the solid sample cell 600 have a storage space in which a sample is accommodated.

[0044] The liquid sample cell 500 contains a liquid sample and includes a section (hereinafter also referred to as an agitation section) in which the cross section of the storage space parallel to the bottom surface is not a circle centered on the rotation axis of the sample cell. The agitation section is a section provided to agitate the liquid sample contained in the liquid sample cell 500. Specifically, as shown in FIG. 5 , the liquid sample cell 500 includes a cylindrical section with an open top, a film 502, and fins 504 serving as the agitation section. The cylindrical section includes an outer member 506 and an inner member 508. The outer member 506 and the inner member 508 have a substantially cylindrical shape and have openings on the upper and lower sides. The inner member 508 is inserted inside the outer member 506. The film 502 is sandwiched and fixed between the outer member 506 and the inner member 508, covering the lower opening of the inner member 508. A liquid sample to be analyzed by the X-ray fluorescence analysis system 100 is placed in a space (storage space) surrounded by the film 502 together with the inner member 508. Since the inner member 508 is approximately cylindrical, the storage space of the liquid sample cell 500 has an approximately cylindrical shape.

[0045] The fins 504 are provided inside the cylindrical portion. Specifically, the fins 504 have a predetermined length in the radial direction of the storage space and in the direction of the rotation axis. For example, the fins 504 have a predetermined length in the radial direction (X direction) and in the direction of the rotation axis (Z direction) of the storage space. The fins 504 are arranged from the inner wall of the cylindrical portion (inner member 508) toward the center. In the example shown in FIG. 5, the fins 504 have a rectangular plate shape whose length in the Y direction is shorter than their lengths in the radial direction and in the direction of the rotation axis. The lengths of the storage space in the radial direction and in the direction of the rotation axis may be long enough to stir the liquid sample. For example, the radial length of the storage space is desirably about one-third the diameter of the cylindrical portion. Furthermore, the length in the direction of the rotation axis is desirably about one-third the height of the cylindrical portion.

[0046] The liquid sample cell 500 according to the first embodiment is required to have at least one fin 504. However, it is preferable that the liquid sample cell 500 have two or more fins 504. In the example shown in Fig. 5, the liquid sample cell 500 has two fins 504 that are positioned at different distances from the bottom surface in the direction of the rotation axis (z-axis). The fin 504 on the left side of Fig. 5 is located at a lower height from the surface of the film 502 than the fin 504 on the right side.

[0047] Furthermore, the shape of the fins 504 in the XZ plane is not limited to a rectangular shape, and may be other shapes. For example, the shape of the fins 504 may be a circle or a triangle. Furthermore, in the embodiment shown in FIG. 5, the fins 504 may have a shape in which each side (or some sides) is wavy or arc-shaped.

[0048] Furthermore, in FIG. 5, the fins 504 are formed integrally with the cylindrical portion, but the cylindrical portion and the fins 504 may be formed separately, and the fins 504 may be fitted to the cylindrical portion.

[0049] Furthermore, it is desirable that the cylindrical portion and fins 504 are made of the same material. By using the same material for the cylindrical portion and fins 504, the impact on analytical accuracy of noise other than fluorescent X-rays emitted from the liquid sample to be analyzed can be reduced.

[0050] The solid sample cell 600 accommodates a solid sample. Specifically, as shown in FIG. 6, the solid sample cell 600 has a substantially cylindrical shape with an open top surface and a smaller opening on the bottom surface. The solid sample is accommodated between the top and bottom surfaces. The solid sample is exposed from the opening on the bottom surface. When analyzing a powdered solid sample, a film 502 may be provided on the opening on the bottom surface.

[0051] Next, we will explain the operation of the fluorescent X-ray analysis system 100. The fluorescent X-ray analysis system 100 operates in operation modes including a non-stirring measurement mode and a stirring measurement mode. Figure 7 is a time chart for explaining each operation mode.

[0052] The upper part of Fig. 7 shows information indicating the angle at which the fluorescent X-rays are measured (the angle between the surface of the above-mentioned spectroscopic element and the traveling direction of the fluorescent X-rays incident on the detector 108). The middle part of Fig. 7 shows information indicating the rotation speed when the fluorescent X-ray analysis system 100 operates in the non-stirring measurement mode. The lower part of Fig. 7 shows information indicating the rotation speed when the fluorescent X-ray analysis system 100 operates in the stirring measurement mode.

[0053] The non-stirred measurement mode is a measurement mode in which the solid sample cell 600 is placed on the sample stage 102, and the detector 108 performs measurement while the rotation mechanism 104 rotates at a constant rotation speed under the control of the speed control unit 404. Specifically, the non-stirred measurement mode includes only a constant speed rotation period. First, a solid sample to be measured is placed in the solid sample cell 600 shown in FIG. 6. The solid sample is exposed from an opening on the bottom surface of the solid sample cell 600. The solid sample cell 600 is placed on the sample stage 102.

[0054] Next, at time t0, the speed control unit 404 instructs the rotation mechanism 104 to rotate the rotation mechanism 104 at a constant rotation speed. As a result, the solid sample cell 600 rotates in the XY plane from time t0 to time t1. Next, at time t1, the detector 108 starts measuring the fluorescent X-ray intensity at the peak angle of line A (any fluorescent X-ray). From time t1 to time t2, the detector 108 measures the fluorescent X-ray intensity at the peak angle. Next, at time t2, the detector 108 stops measuring the fluorescent X-ray intensity. From time t2 to time t3, the detector 108 does not measure the fluorescent X-ray intensity. Next, at time t3, the detector 108 starts measuring the fluorescent X-ray intensity at the background angle of line A (any fluorescent X-ray). From time t3 to time t4, the detector 108 measures the fluorescent X-ray intensity at the background angle. Then, after time t4, the analysis unit 402 analyzes the elements that generate the fluorescent X-rays associated with line A based on the fluorescent X-ray intensity at the peak angle and the fluorescent X-ray intensity at the background angle.

[0055] The rotation speed of the solid sample cell 600 in the non-stirred measurement mode is constant (e.g., 60 rpm). Rotating the surface of the solid sample irradiated with primary X-rays at a constant rotation speed reduces variations in analysis results due to unevenness on the solid sample surface. Note that a constant rotation speed in the non-stirred measurement mode means that the rotation speed is constant during the period when the detector 108 is measuring the intensity of the fluorescent X-rays. In other words, even during operation in the non-stirred measurement mode, the rotation speed may change as long as the detector 108 is not measuring the intensity of the fluorescent X-rays. For example, even during operation in the non-stirred measurement mode, the rotation speed may change during the period until the detector 108 starts measuring the intensity of the fluorescent X-rays (the period during which the rotation speed changes from the initial state to a constant rotation speed) or during the period after the detector 108 finishes measuring the intensity of the fluorescent X-rays. The range of the constant rotation speed is a range of rotation speeds that can reduce variations in analysis accuracy due to unevenness on the surface of the solid sample. For example, even if the speed control unit 404 controls the rotation mechanism 104 to rotate at a constant rotation speed, the rotation speed of the rotation mechanism 104 may change depending on given conditions (such as changes in temperature or humidity). The rotation speed of the rotation mechanism 104 may also change depending on the characteristics of the rotation mechanism 104 (such as manufacturing variations and reliability). However, as long as the rotation speed is within a range that can reduce variations in analytical accuracy due to unevenness on the surface of the solid sample, even if there is some variation, it will be included in the range of a constant rotation speed.

[0056] The stirring measurement mode is a measurement mode for analyzing a liquid sample in which the liquid sample cell 500 is placed on the sample stage 102. Specifically, the stirring measurement mode includes a stirring period and a post-stirring measurement period.

[0057] The stirring period is a period during which the speed control unit 404 stirs the liquid sample by rotating the rotation mechanism 104 at a varying rotation speed. Specifically, during the stirring period, the speed control unit 404 instructs the rotation mechanism 104 to discontinuously change the rotation speed. For example, during the stirring period, the speed control unit 404 instructs the rotation mechanism 104 to rotate in the forward direction for a predetermined period of time, and then instructs it to rotate in the reverse direction. The forward direction and the reverse direction are rotation directions within the XY plane, and either may be clockwise. Hereinafter, the forward direction is defined as clockwise, and the reverse direction is defined as counterclockwise. Furthermore, the rotation speed in the forward direction is defined as a positive value, and the rotation speed in the reverse direction is defined as a negative value.

[0058] The post-mixing measurement period is a period during which the detector 108 performs measurement after the liquid sample has been mixed. Specifically, the detector 108 measures the intensity of fluorescent X-rays emitted from the sample during the post-mixing measurement period, which is after the mixing period. The speed control unit 404 may instruct the rotation mechanism 104 to rotate during the post-mixing measurement period. For example, during the post-mixing measurement period, the speed control unit 404 may instruct the rotation mechanism 104 to rotate in the forward direction for a predetermined time, and then instruct it to rotate in the reverse direction. Furthermore, the speed control unit 404 may instruct the rotation mechanism 104 to stop during the post-mixing measurement period.

[0059] 7, first, a liquid sample to be measured is placed in the liquid sample cell 500 shown in Fig. 5. The liquid sample cell 500 is placed on the sample stage 102.

[0060] Next, at time t0, the speed control unit 404 instructs the rotation mechanism 104 to rotate the rotation mechanism 104 clockwise at a predetermined rotation speed (e.g., 60 rpm). As a result, the sample cell begins to rotate clockwise within the XY plane from time t0. After a predetermined time (e.g., 5 seconds) has elapsed, the speed control unit 404 instructs the rotation mechanism 104 to rotate the rotation mechanism 104 counterclockwise at a predetermined rotation speed (e.g., −60 rpm). As a result, the sample cell begins to rotate counterclockwise within the XY plane. Note that the rotation speed may be changed discontinuously from 60 rpm to −60 rpm after a predetermined time has elapsed from time t0, or may be changed continuously from 60 rpm to −60 rpm over a certain period of time. Values ​​sufficient to agitate the liquid sample are set for the time t1 and the rotation speed.

[0061] The speed control unit 404 may issue an instruction to discontinuously change the rotation speed at least once during the stirring period, but preferably issues the instruction multiple times. Specifically, for example, the speed control unit 404 preferably issues an instruction to the rotation mechanism 104 to rotate alternately in the forward direction (e.g., a rotation speed of 60 rpm) and the reverse direction (e.g., a rotation speed of -60 rpm) every certain time (e.g., 5 seconds). Furthermore, for example, the speed control unit 404 may issue an instruction to the rotation mechanism 104 to rotate in the forward direction (e.g., a rotation speed of 60 rpm) and to stop (a rotation speed of 0 rpm) every certain time (e.g., 5 seconds). In the example shown in FIG. 7, the period from time t0 to time t1 includes two periods of forward rotation and two periods of reverse rotation.

[0062] The liquid sample contained in the liquid sample cell 500 is agitated by changing the rotation speed of the liquid sample cell 500. Specifically, after the liquid sample cell 500 has rotated at a constant rotation speed for a sufficient period of time, the liquid sample rotates at the same rotation speed as the liquid sample cell 500. In this state, the relative velocity between the cylindrical portion and the liquid sample is zero. If a liquid sample were contained in a cylindrical liquid sample cell 500 without a stirring portion, when the rotation speed of the liquid sample cell 500 changes, the liquid sample would rotate at the previous rotation speed according to the law of inertia. However, since the stirring portion is provided in the present disclosure, when the rotation speed of the liquid sample cell 500 changes, the stirring portion prevents the liquid sample near the stirring portion from rotating at the rotation speed according to the law of inertia. As a result, turbulence occurs in the flow of the liquid sample, starting from the stirring portion, and the liquid sample is agitated.

[0063] Next, at time t1, detector 108 starts measuring the fluorescent X-ray intensity at the peak angle of line A (any fluorescent X-ray). During the period from time t1 to time t2, detector 108 measures the fluorescent X-ray intensity at the peak angle. Speed ​​control unit 404 may instruct rotation mechanism 104 to rotate during the post-mixing measurement period. For example, during the period from time t1 to time t2, speed control unit 404 may instruct rotation mechanism 104 to rotate in the forward direction at a predetermined rotation speed (e.g., 30 rpm) for a predetermined time (e.g., 10 seconds), and then instruct rotation in the reverse direction at a predetermined rotation speed (e.g., -30 rpm) for a predetermined time (e.g., 10 seconds). Furthermore, speed control unit 404 may instruct rotation mechanism 104 to stop during the post-mixing measurement period.

[0064] At time t1, the liquid sample is in a sufficiently stirred state. Therefore, whether or not to rotate the rotation mechanism 104 during the post-stirring measurement period is appropriately determined depending on whether or not sedimentary components contained in the liquid sample will settle during the post-stirring measurement period. In the example shown in Figure 7, the period from time t1 to time t2 includes one period of forward rotation and one period of reverse rotation. Furthermore, the forward and reverse rotation speeds during the post-stirring measurement period are half the forward and reverse rotation speeds during the stirring period.

[0065] Next, at time t2, detector 108 stops measuring the fluorescent X-ray intensity. During the period from time t2 to time t3, detector 108 does not measure the fluorescent X-ray intensity. The rotation speed during the stirring period from time t2 to time t3 may be the same as or different from that during the stirring period from time t0 to time t1. In the example shown in FIG. 7, the period from time t2 to time t3 includes two periods of forward rotation and two periods of reverse rotation.

[0066] Next, at time t3, measurement of the fluorescent X-ray intensity at the background angle of line A (any fluorescent X-ray) begins. During the period from time t3 to time t4, detector 108 measures the fluorescent X-ray intensity at that background angle. The rotation speed during the post-mixing measurement period from time t3 to time t4 may be the same as or different from that during the post-mixing measurement period from time t1 to time t2. In the example shown in FIG. 7, the period from time t3 to time t4 includes one period of forward rotation and one period of reverse rotation.

[0067] Then, after time t4, the analysis unit 402 analyzes the elements that generate the fluorescent X-rays associated with line A based on the fluorescent X-ray intensity at the peak angle and the fluorescent X-ray intensity at the background angle.

[0068] As described above, according to the present disclosure, by using the rotation mechanism 104 to reduce the effect of the surface roughness of the solid sample, an increase in manufacturing costs can be suppressed, and by providing the liquid sample cell 500 with a stirring section, the effect on measurement results of settling of sedimentary components can be reduced.

[0069] The present disclosure may be applied to either a wavelength-dispersive or energy-dispersive X-ray fluorescence analysis system 100. Furthermore, the present disclosure is not limited to the above-described embodiment and various modifications are possible. The configuration of the above-described X-ray fluorescence analysis system 100 is merely an example and is not intended to be limiting. The configuration may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiment, that provides the same effects, or that achieves the same purpose. For example, in FIG. 7, the length and number of stirring periods are preset. However, the length and number of stirring periods may be varied based on the analysis results.

[0070] 8 is a flowchart showing the operation of the fluorescent X-ray analysis system 100 in the mixing measurement mode according to the second embodiment. In the second embodiment, a case will be described in which only the intensity at the peak angle is measured, and the background intensity near the peak angle is not measured. First, a provisional measurement before mixing is performed (S802). As an initial value, a variable n representing the number of mixing times is set to 0.

[0071] Specifically, first, a liquid sample to be measured is placed in the liquid sample cell 500 shown in Figure 5. The liquid sample cell 500 is placed on the sample stage 102. At the time of S802, the liquid sample cell 500 is not rotating. Then, the liquid sample is irradiated with primary X-rays, and the detector 108 measures the intensity of the fluorescent X-rays generated from the liquid sample. The intensity measured in S802 is defined as I0.

[0072] Next, the speed control unit 404 instructs the rotation mechanism 104 to discontinuously change the rotation speed during the agitation period (S804). S804 is an agitation period, and is the same as one agitation period included in Fig. 7. For example, the agitation period of S804 includes two periods of forward rotation and two periods of reverse rotation.

[0073] Next, a provisional measurement after mixing is performed (S806). As will be described later, steps S804-S814 are repeatedly executed. S806 is a step in which the detector 108 measures the intensity of fluorescent X-rays during the nth post-mixing measurement period, and when n is 1, this is the first post-mixing measurement period. The step of S806 is the same as one post-mixing measurement period included in FIG. 7. The detector 108 measures the intensity of fluorescent X-rays generated from the liquid sample. The intensity measured in S806 is designated as I1.

[0074] Next, the number of times of mixing n is incremented (S808). For example, if step S808 is the first time, the number of times of mixing, which is 0, is incremented to 1.

[0075] Next, based on the intensity of the fluorescent X-rays measured during the nth post-mixing measurement period and the intensity of the fluorescent X-rays measured during the n+1th post-mixing measurement period, it is determined whether or not to set the (n+2)th agitation period (S810). Specifically, if the difference or ratio between the intensity of the fluorescent X-rays measured during the nth post-mixing measurement period and the intensity of the fluorescent X-rays measured during the (n+1)th post-mixing measurement period is greater than a predetermined value, the (n+2)th agitation period is set. For example, when n is 1, the intensity I0 is the intensity measured in S802. Also, the intensity of the fluorescent X-rays measured during the first post-mixing measurement period is the intensity I1 measured in S806. The difference between the intensity I0 and the intensity I1 is the theoretical intensity standard deviation σI1. calc If it is smaller than the specified magnification α, the process proceeds to S816, and if it is equal to or larger than the specified magnification α, the process proceeds to S812. Note that the specified magnification α is a value set in advance.

[0076] In S812, it is determined whether the number of stirring times n is greater than a preset maximum number of stirring times. If the number of stirring times n is greater than the maximum number of stirring times, the process proceeds to S816, and if it is smaller, the process proceeds to S814. The maximum number of stirring times may be set to any value, for example, 10.

[0077] In S814, the intensity I1 is set as the value of the intensity I0. Specifically, when the number of mixing times n is 1, the intensity I1 measured in S806 for the first time is set as the value of the intensity I0. Then, the process proceeds to S804 again.

[0078] If it is determined in S810 and S812 that the process proceeds to S816, the actual measurement is performed (S816). The step of S816 is the same as one post-agitation measurement period included in FIG.

[0079] According to the second embodiment, the stirring measurement mode alternately includes stirring periods and post-stirring measurement periods, and also includes the steps of: measuring the intensity of fluorescent X-rays by detector 108 during the nth post-stirring measurement period; measuring the intensity of fluorescent X-rays by detector 108 during the (n+1)th post-stirring measurement period; and determining whether to set the (n+2)th stirring period based on the intensity of fluorescent X-rays measured during the nth post-stirring measurement period and the intensity of fluorescent X-rays measured during the (n+1)th post-stirring measurement period.

[0080] When the liquid sample is well stirred, the difference between the intensity I0 and the intensity I1 is the theoretical intensity standard deviation σI1 calc On the other hand, if the liquid sample is not sufficiently stirred, the difference between the intensity I0 and the intensity I1 is smaller than the theoretical intensity standard deviation σI1 calc According to the second embodiment, the sample can be analyzed after a necessary and sufficient number of stirring periods have passed.

[0081] [Variation 1] FIG. 9 shows a top view and a cross-sectional view of a liquid sample cell 500 according to Modification 1. Modification 1 may be applied to either the first or second embodiment. The liquid sample cell 500 according to Modification 1 has a cylindrical portion with an open top and a lid portion 902 that fits into the opening. The fins 504 are integrally formed with the lid portion 902. Specifically, the lid portion 902 has a disk-shaped portion that covers the opening on the top surface of the cylindrical portion, two columnar portions extending substantially perpendicularly from the disk-shaped portion, and fins 504 (stirring portions) provided on each of the two columnar portions. The two columnar portions are spaced apart by the inner diameter of the cylindrical portion, so that the lid portion 902 fits into the cylindrical portion. In the example shown in FIG. 9, the fins 504 have the same shape and are provided at the same height as those in the first and second embodiments. The cylindrical portion and the film 502 are both the same as those in the first and second embodiments.

[0082] According to Modification 1, it is possible to reduce the possibility of leakage of the liquid sample by providing lid portion 902. Furthermore, since the cylindrical portion and film 502 according to Modification 1 are similar to the conventionally used configuration, by manufacturing only lid portion 902, it can be used in combination with the conventionally used configuration.

[0083] [Variation 2] 10 shows a top view and a cross-sectional view of a liquid sample cell 500 according to Modification 2. Modification 2 may be applied to either the first or second embodiment. The liquid sample cell 500 according to Modification 2 has a rectangular parallelepiped tubular portion 1002 instead of the cylindrical portion of the first and second embodiments. The rectangular parallelepiped tubular portion 1002 has a storage space for storing a sample, similar to the cylindrical portion.

[0084] The rectangular parallelepiped tubular portion 1002 includes an outer member 506 and an inner member 508. The outer member 506 and the inner member 508 have a roughly rectangular parallelepiped shape and have openings on the upper and lower sides. The inner member 508 is inserted inside the outer member 506. The film 502 is sandwiched and fixed between the outer member 506 and the inner member 508, and covers the opening on the lower side of the inner member 508. A liquid sample to be analyzed by the X-ray fluorescence analysis system 100 is placed in the space enclosed by the inner member 508 and the outer member 506. Because the inner member 508 has a roughly rectangular parallelepiped shape, the storage space of the liquid sample cell 500 also has a roughly rectangular parallelepiped shape.

[0085] Fins 504 are provided on the inside of the cylindrical portion. Fins 504 are arranged from the inner wall toward the center of rectangular parallelepiped tubular portion 1002. Film 502 is the same as in the first and second embodiments.

[0086] According to the second modification, the corners of the inner member 508 and the two fins 504 function as agitators. That is, when the rotation speed of the liquid sample cell 500 changes, the liquid sample near the corners is prevented from rotating at a rotation speed according to the law of inertia. As a result, when the rotation speed of the liquid sample cell 500 changes, turbulence occurs in the flow of the liquid sample starting from the agitator, and the liquid sample is agitated. Therefore, agitation can be performed in a shorter time than in the first and second embodiments. Note that, although it is desirable to provide the fins 504 in the second modification, the fins 504 in the second modification may be omitted.

[0087] [Variation 3] FIG. 11 shows a top view and a cross-sectional view of a liquid sample cell 500 according to Modification 3. Modification 3 may be applied to either the first or second embodiment. The liquid sample cell 500 according to Modification 3 differs from the example shown in FIG. 5 in that the height of the fins 504 is different, but the other aspects are the same. As shown in FIG. 11, the two fins 504 are provided at the same height (position in the Z direction). The height of each fin 504 may be set according to the characteristics of the liquid sample. For example, the height of the fins 504 may be different or the same depending on the viscosity of the liquid sample, the ease of settling of sedimentary components in the sample, etc. Also, as described above, the shape of the fins 504 does not have to be rectangular.

[0088] [Variation 4] FIG. 12 shows a top view and a cross-sectional view of a sample cell according to Modification 4. Modification 4 may be applied to either the first or second embodiment. The only difference from the example shown in FIG. 5 is that the liquid sample cell 500 is large enough to be placed inside the solid sample cell 600; otherwise, the configuration is the same. When analyzing a liquid sample in Modification 4, the liquid sample cell 500 containing the liquid sample is placed in the storage space of the solid sample cell 600, and the solid sample cell 600 is placed on the sample stage 102. When analyzing a solid sample, the solid sample is placed in the storage space of the solid sample cell 600, and the solid sample cell 600 is placed on the sample stage 102. In Modification 4, the two fins 504 may also have the same height, and the shape of the fins 504 does not have to be rectangular.

[0089] In Modification 4, whether analyzing a liquid sample or a solid sample, the solid sample cell 600 is placed on the sample stage 102. In other words, there is no need to design the sample stage 102 to accommodate two different types of sample cells. In addition, the device for transporting sample cells included in the conventional X-ray fluorescence analysis system 100 can be used. This simplifies the configuration and prevents increases in manufacturing costs. [Explanation of symbols]

[0090] 100 X-ray fluorescence analysis system, 102 sample stage, 104 Rotation mechanism, 106 X-ray source, 108 detectors, 300 information processing device, 302 Arithmetic section, 304 storage section, 306 Display section, 308 input / output section, 310 internal bus, 402 Analysis Department, 404 Speed ​​control section, 500 liquid sample cells, 502 film, 504 Finn, 506 outer member, 508 inner member, 600 solid sample cell, 902 Lid, 1002 A rectangular tubular part.

Claims

1. a sample stage on which a sample cell having a storage space for storing a sample is placed and which has an opening through which the bottom surface of the sample cell is exposed; a rotation mechanism that rotates the sample cell placed on the sample stage; an X-ray source that irradiates the lower surface of the sample stage with X-rays from below the sample stage through an opening in the sample stage; a detector for measuring the intensity of fluorescent X-rays emitted from the sample; a speed control unit that controls a rotation speed of the rotation mechanism; An X-ray fluorescence analysis system comprising: The sample cell is a liquid sample cell in which a liquid sample is accommodated, the cross section of the accommodation space parallel to the lower surface including a portion that is not a circle centered on the rotation axis of the sample cell; a solid sample cell in which a solid sample is accommodated; Including, a non-stirring measurement mode in which the detector performs measurement while the rotation mechanism rotates at a constant rotation speed under the control of the speed control unit; a stirring measurement mode including a stirring period in which the speed control unit rotates the rotation mechanism at a varying rotation speed to stir the liquid sample, and a post-stirring measurement period in which the detector performs measurement after the liquid sample has been stirred; An X-ray fluorescence analysis system, characterized in that it operates in an operation mode including:

2. the sample stage is capable of mounting the liquid sample cell and the solid sample cell thereon; In the non-stirring measurement mode, the solid sample cell is placed on the sample stage, In the stirring measurement mode, the liquid sample cell is placed on the sample stage.

2. The X-ray fluorescence analysis system according to claim 1.

3. The storage space of the liquid sample cell has a substantially cylindrical shape, the liquid sample cell has one or more fins each having a predetermined length in the radial direction of the storage space and in the direction of the rotation axis; 3. The X-ray fluorescence analysis system according to claim 1, wherein the X-ray fluorescence analysis system is a system for analyzing a sample of a sample.

4. the liquid sample cell has a cylindrical portion with an open top and a lid portion that fits into the opening; The fin is integrally formed with the lid.

4. The X-ray fluorescence analysis system according to claim 3.

5. the liquid sample cell has a cylindrical portion with an open top surface; The fin is integrally formed with the cylindrical portion.

4. The X-ray fluorescence analysis system according to claim 3.

6. the liquid sample cell has a cylindrical portion with an open top surface; the cylindrical portion and the fins are formed separately; The fin is fitted to the cylindrical portion.

4. The X-ray fluorescence analysis system according to claim 3.

7. The cylindrical portion and the fins are formed of the same material.

5. The X-ray fluorescence analysis system according to claim 4.

8. Further comprising the liquid sample cell, 3. The X-ray fluorescence analysis system according to claim 1, wherein the X-ray fluorescence analysis system is a system for analyzing a sample of a sample.

9. the speed control unit instructs the rotation mechanism to discontinuously change the rotation speed during the stirring period.

2. The X-ray fluorescence analysis system according to claim 1.

10. the speed control unit instructs the rotation mechanism to rotate in a forward direction for a predetermined time during the stirring period, and then instructs the rotation mechanism to rotate in a reverse direction.

10. The X-ray fluorescence analysis system according to claim 1 or 9.

11. the speed control unit issues an instruction to stop the rotation mechanism during the post-stirring measurement period.

10. The X-ray fluorescence analysis system according to claim 1 or 9.

12. the speed control unit instructs the rotation mechanism to rotate during the post-stirring measurement period.

10. The X-ray fluorescence analysis system according to claim 1 or 9.

13. the speed control unit instructs the rotation mechanism to rotate in a forward direction for a predetermined time during the post-stirring measurement period, and then instructs the rotation mechanism to rotate in a reverse direction.

13. The X-ray fluorescence analysis system according to claim 12.

14. A non-transitory computer-readable information storage medium storing an X-ray fluorescence analysis program executed by a computer used in an X-ray fluorescence analysis system, The X-ray fluorescence analysis system includes: a sample stage on which a sample cell having a storage space for storing a sample is placed and which has an opening through which the bottom surface of the sample cell is exposed; a rotation mechanism that rotates the sample cell placed on the sample stage; an X-ray source that irradiates the lower surface of the sample stage with X-rays from below the sample stage through an opening in the sample stage; a detector for measuring the intensity of fluorescent X-rays emitted from the sample; a speed control unit that controls a rotation speed of the rotation mechanism; and The sample cell is a liquid sample cell in which a liquid sample is accommodated, the cross section of the accommodation space parallel to the lower surface including a portion that is not a circle centered on the rotation axis of the sample cell; a solid sample cell in which a solid sample is accommodated; Including, The X-ray fluorescence analysis program a non-stirring measurement mode in which the detector performs measurement while the rotation mechanism rotates at a constant rotation speed under the control of the speed control unit; a stirring measurement mode including a stirring period in which the speed control unit rotates the rotation mechanism at a varying rotation speed to stir the liquid sample, and a post-stirring measurement period in which the detector performs measurement after the liquid sample has been stirred; 2. An information storage medium for causing the computer to execute an operation mode including:

15. the stirring measurement mode includes the stirring period and the post-stirring measurement period alternately; The X-ray fluorescence analysis program, when executing the stirring measurement mode, instructs the computer to: a step of measuring an intensity of fluorescent X-rays by the detector during the n-th post-stirring measurement period; a step of measuring an intensity of fluorescent X-rays by the detector during the (n+1)th post-stirring measurement period; a step of determining whether or not to set the (n+2)th agitation period based on the intensity of the fluorescent X-rays measured during the nth agitation measurement period and the intensity of the fluorescent X-rays measured during the (n+1)th agitation measurement period; 15. The information storage medium according to claim 14, wherein the information storage medium executes the following.

16. In the determining step, when a difference or a ratio between the intensity of the fluorescent X-rays measured during the nth post-agitation measurement period and the intensity of the fluorescent X-rays measured during the (n+1)th post-agitation measurement period is larger than a predetermined value, the (n+2)th post-agitation measurement period is set.

16. The information storage medium according to claim 15.

17. The storage space of the liquid sample cell has a substantially cylindrical shape, the liquid sample cell has one or more fins having predetermined lengths in the radial and axial directions of the storage space; 2. A liquid sample cell for use in the X-ray fluorescence analysis system according to claim 1.

18. the liquid sample cell has a cylindrical portion with an open top surface; the cylindrical portion and the fins are formed separately; The fin is fitted to the cylindrical portion.

18. A liquid sample cell according to claim 17.

19. The cylindrical portion and the fins are formed of the same material.

20. The liquid sample cell of claim 18.

20. a sample stage on which a sample cell having a storage space for storing a sample is placed and which has an opening through which the bottom surface of the sample cell is exposed; a rotation mechanism that rotates the sample cell placed on the sample stage; an X-ray source that irradiates the lower surface of the sample stage with X-rays from below the sample stage through an opening in the sample stage; a detector for measuring the intensity of fluorescent X-rays emitted from the sample; a speed control unit that controls a rotation speed of the rotation mechanism; An X-ray fluorescence analysis program executed by a computer for use in an X-ray fluorescence analysis system having the following: The sample cell is a liquid sample cell in which a liquid sample is accommodated, the cross section of the accommodation space parallel to the lower surface including a portion that is not a circle centered on the rotation axis of the sample cell; a solid sample cell in which a solid sample is accommodated; Including, a non-stirring measurement mode in which the detector performs measurement while the rotation mechanism rotates at a constant rotation speed under the control of the speed control unit; a stirring measurement mode including a stirring period in which the speed control unit rotates the rotation mechanism at a varying rotation speed to stir the liquid sample, and a post-stirring measurement period in which the detector performs measurement after the liquid sample has been stirred; and a program for X-ray fluorescence analysis, the program causing the computer to execute an operation mode including the steps of:

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