Fluorescent x-ray analysis system, information storage medium, liquid sample cell used for fluorescent x-ray analysis system, and fluorescent x-ray analysis program

Abstract

The present invention reduces the effect that precipitation of a degradable component has on a measurement result while suppressing any increase in manufacturing cost. Provided is a fluorescent X-ray analysis system comprising a rotation mechanism that causes a sample cell to rotate and a speed control unit that controls the rotation speed of the rotation mechanism, the fluorescent X-ray analysis system operating in operation modes including: a non-agitation measurement mode in which a detector performs measurement while the rotation mechanism is rotating at a constant speed under the control of the speed control unit; and an agitation measurement mode including an agitation period in which a liquid sample is agitated due to the speed control unit causing the rotation mechanism to rotate at a rotation speed at which a change occurs, and a post-agitation measurement period in which the detector performs measurement after the liquid sample has been agitated. A liquid sample cell accommodates the liquid sample and includes a portion in which the cross section of an accommodation space parallel to the lower surface is not a circle centered on the rotation axis of the sample cell.

Description

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

[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.

[0002] As a device for measuring elements contained in a sample and the concentration of the elements, an X-ray fluorescence analyzer is known. The X-ray fluorescence analyzer can perform analysis whether the sample to be analyzed is solid or liquid.

[0003] When analyzing a solid sample, there is a possibility that accurate analysis cannot be performed due to the surface roughness of the solid sample. In order to reduce the influence of the surface roughness, there is an X-ray fluorescence analyzer that measures while rotating the sample in the plane.

[0004] When analyzing a liquid sample, sedimentable components in the sample may settle, and the measurement results may change over time. In order to prevent sedimentable components from settling during measurement, there is an X-ray fluorescence analyzer that provides a stirring blade inside the sample cell and rotates it inside the sample cell (see Patent Documents 1 and 2 below).

[0005] There are also an X-ray diffractometer and a spectrophotometer that perform measurement after rotating the sample holder itself filled with a liquid sample (see Patent Documents 3 and 4).

[0006] Japanese Utility Model Publication No. 52-046791, Japanese Examined Patent Publication No. 53-009558, Japanese Unexamined Patent Application Publication No. 10-38772, Japanese Unexamined Patent Application Publication No. 2009-128043

[0007] When providing a stirring blade inside the sample cell as in Patent Documents 1 and 2, a mechanism for rotating the stirring blade needs to be provided separately, which increases the manufacturing cost. In particular, when rotating the stirring blade using magnetic force, the ferromagnetic material contained in the stirring blade may affect the measurement results.

[0008] Even when the sample cell itself is configured to rotate, there is a possibility that the liquid sample is not sufficiently stirred inside the cylindrical sample cell as in Patent Documents 3 and 4.

[0009] This disclosure has been made in view of the above-mentioned problems, and its purpose is to provide a fluorescent X-ray analysis system, an information storage medium, a liquid sample cell used in a fluorescent X-ray analysis system, and a fluorescent X-ray analysis program that can reduce the impact on measurement results due to the precipitation of sedimentary components by thoroughly stirring the liquid sample, while suppressing an increase in manufacturing costs by using a rotation mechanism to reduce the influence of the surface roughness of the solid sample.

[0010] (1) A fluorescent X-ray analysis system according to one aspect of the present disclosure is a fluorescent X-ray analysis system comprising: a sample stage on which a sample cell having a storage space for a sample is placed and which has an opening that exposes the lower surface of the sample cell; a rotation mechanism for rotating 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 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 contains a liquid sample, and The device comprises a liquid sample cell whose cross-section parallel to the lower surface includes a portion of the storage space 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 an operating mode that includes: a non-stirring measurement mode in which the detector performs measurements while the rotation mechanism rotates at a constant rotational speed under the control of the speed control unit; a stirring period in which the liquid sample is stirred by the speed control unit rotating the rotation mechanism at a changing rotational speed; and a post-stirring measurement period in which the detector performs measurements after the liquid sample has been stirred.

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

[0012] (3) In another embodiment of the present disclosure, the X-ray fluorescence analysis system is characterized in that the containment space of the liquid sample cell has a substantially cylindrical shape, and the liquid sample cell has one or more fins having a predetermined length in the radial and rotational axis directions of the containment space.

[0013] (4) In another embodiment of the present disclosure, the X-ray fluorescence analysis system is characterized in that 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 fins are formed integrally with the lid portion.

[0014] (5) In another embodiment of the present disclosure, the X-ray fluorescence analysis system is characterized in that the liquid sample cell has a cylindrical portion with an open top surface, and the fins are integrally formed with the cylindrical portion.

[0015] (6) In another embodiment of the present disclosure, the X-ray fluorescence analysis system is characterized in that 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) A fluorescent X-ray analysis system according to another aspect of the present disclosure is characterized in that the cylindrical portion and the fin are formed of the same material.

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

[0018] (9) In another embodiment of the present disclosure, the X-ray fluorescence analysis system is characterized in that the speed control unit instructs the rotation mechanism to discontinuously change the rotation speed during the stirring period.

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

[0020] (11) In another embodiment of the present disclosure, the X-ray fluorescence analysis system is characterized in that the speed control unit gives an instruction to stop the rotation mechanism during the post-stirring measurement period.

[0021] (12) In another embodiment of the present disclosure, the X-ray fluorescence analysis system is characterized in that the speed control unit gives an instruction to rotate the rotation mechanism during the post-stirring measurement period.

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

[0023] (14) An information storage medium according to one aspect of the present disclosure is a non-temporary computer-readable information storage medium for storing an X-ray fluorescence analysis program executed on a computer used in an X-ray fluorescence analysis system, the X-ray fluorescence analysis system comprising: a sample stage on which a sample cell having a storage space for accommodating a sample is placed and which has an opening that exposes the lower surface of the sample cell; a rotation mechanism for rotating 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 the opening of the sample stage; a detector for measuring the intensity of X-ray fluorescence 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 contained, and the cross-section of the containment space parallel to the lower 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 contained, and the fluorescent X-ray analysis program is characterized in that it causes the computer to execute an operation mode including: a non-stirred measurement mode in which the detector performs measurements while the rotation mechanism is rotating at a constant rotational speed under the control of the speed control unit; a stirring measurement mode in which the liquid sample is stirred by the speed control unit rotating the rotation mechanism at a changing rotational speed; and a post-stirred measurement period in which the detector performs measurements 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 includes, alternately, the stirring period and the post-stirring measurement period, and the fluorescent X-ray analysis program, when executing the stirring measurement mode, causes the computer to perform the steps of: measuring the intensity of fluorescent X-rays with the detector during the nth post-stirring measurement period; measuring the intensity of fluorescent X-rays with the detector during the (n+1)th post-stirring measurement period; and determining whether or not 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.

[0025] (16) In another aspect of the present disclosure, the information storage medium is characterized in that, in the determination step, the (n+2)th stirring period is set if the difference or ratio between 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 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 containment space of the liquid sample cell has a substantially cylindrical shape, and the liquid sample cell has one or more fins having a predetermined length in the radial and axial directions of the containment space.

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

[0028] (19) In another embodiment of the present disclosure, the liquid sample cell is characterized in that the cylindrical portion and the fins are formed of the same material.

[0029] (20) A fluorescent X-ray analysis program according to one aspect of the present disclosure is a fluorescent X-ray analysis program executed by a computer used in a fluorescent X-ray analysis system having a sample stage on which a sample cell having a storage space for a sample is placed and which has an opening that exposes the lower surface of the sample cell; a rotation mechanism for rotating 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 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 The invention is characterized in that it causes the computer to execute an operating mode that includes a liquid sample cell containing a liquid sample, the liquid sample cell having a cross-section of the storage space parallel to the lower surface that is not a circle centered on the rotation axis of the sample cell, and a solid sample cell containing a solid sample, the operating mode including a non-stirring measurement mode in which the detector performs measurements while the rotation mechanism is rotating at a constant rotational speed under the control of the speed control unit, a stirring period in which the liquid sample is stirred by the speed control unit rotating the rotation mechanism at a changing rotational speed, and a post-stirring measurement period in which the detector performs measurements after the liquid sample has been stirred.

[0030] This is a diagram illustrating the schematic of the X-ray fluorescence analysis system. This is a top view of the sample stage and rotation mechanism. This is a diagram illustrating the hardware configuration of the information processing device. This is a functional block diagram of the calculation unit. These are top and cross-sectional views of the liquid sample cell. These are top and cross-sectional views of the solid sample cell. This is a time chart for explaining the first embodiment. This is a flowchart for explaining the second embodiment. These are top and cross-sectional views of the liquid sample cell according to Modification 1. These are top and cross-sectional views of the liquid sample cell according to Modification 2. These are top and cross-sectional views of the liquid sample cell according to Modification 3. These are top and cross-sectional views of the sample cell according to Modification 4.

[0031] Hereinafter, preferred embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the figures. Figure 1 is a schematic diagram showing a cross-section of the X-ray fluorescence analysis system 100 according to this embodiment. As shown in Figure 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 Figure 3).

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

[0033] The sample stage 102 has an opening on which a sample cell is placed, exposing the lower surface of the sample cell. Specifically, for example, Figure 2 is an overhead view of the sample stage 102 and the rotating mechanism 104 positioned on the sample stage 102. As shown in Figure 2, the sample stage 102 has an opening at the position where the sample cell is placed. This opening is provided on the path of the primary X-rays emitted from the X-ray source 106. The sample stage 102 according to this embodiment can accommodate both a liquid sample cell 500 and a solid sample cell 600. Note that the sample stage 102 only needs to be able to accommodate the solid sample cell 600, and does not need to be able to accommodate 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 in the opening of the sample stage 102. The actuator rotates a member of the ring-shaped member via a belt (not shown), thereby causing the rotation mechanism 104 to rotate the sample cell placed on the sample stage 102 in the XY plane. Hereafter, the plane horizontal to the surface of the sample stage 102 will be defined as the XY plane (the right direction in Figure 1 is the X direction, and the front direction is the Y direction), and the direction perpendicular to the XY plane (upward direction in Figure 1) will be defined as the Z direction.

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

[0036] Furthermore, a spectroscopic element that spectrally separates fluorescent X-rays of a predetermined wavelength emitted from the sample may be provided. The spectroscopic element is positioned on the path of the primary X-rays or the path of the fluorescent X-rays. In addition, a spectroscopic element and detector 108 may be provided for each element to be analyzed, or a set of spectroscopic elements and detector 108 may rotate. If a set of spectroscopic elements and detector 108 is to rotate, a mechanism (goniometer) for rotating the spectroscopic elements and detector 108 is provided.

[0037] The information processing device 300 controls the operation of the rotating mechanism 104 and the X-ray source 106, analyzes the sample based on the output of the counting unit, and displays and outputs the analysis results. Specifically, for example, the information processing device 300 is a personal computer and includes, as shown in Figure 3, an arithmetic unit 302, a storage unit 304, a display unit 306, an input / output unit 308, and an internal bus 310.

[0038] The calculation unit 302 is a CPU, MPU, etc., and operates according to a program stored in the storage unit 304. Figure 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 performs sample analysis based on the output of the counting unit. The speed control unit 404 controls the rotation speed of the rotation mechanism 104. The calculation unit 302 executes the fluorescence X-ray segment analysis program stored in the storage unit 304, thereby enabling 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-temporary computer-readable information storage medium that stores a fluorescent X-ray analysis program executed by a computer used in the fluorescent X-ray analysis system 100. Specifically, for example, the storage unit 304 is an information recording medium such as a ROM, a RAM, or a hard disk. The storage unit 304 stores the fluorescent X-ray analysis program executed by the arithmetic unit 302. Also, the storage unit 304 operates, for example, as a work memory of the arithmetic unit 302. The fluorescent X-ray analysis program causes the information processing device 300 to execute an operation mode 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 an instruction from the arithmetic unit 302.

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

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

[0043] Next, the sample cell according to the present embodiment will be described. The sample cell used in the present embodiment includes a liquid sample cell 500 and a solid sample cell 600. FIG. 5 is a top view and a cross-sectional view of the liquid sample cell 500 in which a liquid sample is accommodated. FIG. 6 is 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 an accommodation space in which a sample is accommodated.

[0044] The liquid sample cell 500 contains a liquid sample and includes a portion of the storage space parallel to the bottom surface whose cross-section is not a circle centered on the rotation axis of the sample cell (hereinafter also referred to as the stirring section). The stirring section is provided for stirring the liquid sample contained in the liquid sample cell 500. Specifically, as shown in Figure 5, the liquid sample cell 500 includes a cylindrical portion with an open top, a film 502, and a fin 504 which is the stirring section. The cylindrical portion 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 top and bottom. 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 lower opening of the inner member 508. The liquid sample to be analyzed by the X-ray fluorescence analysis system 100 is placed in the space (container space) enclosed by the film 502 together with the inner member 508. Since the inner member 508 is substantially cylindrical, the containment space of the liquid sample cell 500 has a substantially cylindrical shape.

[0045] The fins 504 are provided on the inside of the cylindrical portion. Specifically, the fins 504 have a predetermined length in the radial and rotational axis directions of the containment space. For example, the fins 504 have a predetermined length in the radial direction (X direction) and rotational axis direction (Z direction) of the containment 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 Figure 5, the fins 504 have a rectangular plate shape in which the length in the Y direction is shorter than the lengths in the radial and rotational axis directions. The lengths in the radial and rotational axis directions of the containment space should be sufficient to stir the liquid sample. For example, the radial length of the containment space is preferably about one-third of the diameter of the cylindrical portion. Also, the length in the rotational axis direction is preferably about one-third of the height of the cylindrical portion.

[0046] Incidentally, the liquid sample cell 500 according to the first embodiment only needs to have at least one fin 504. However, it is desirable for the liquid sample cell 500 to have two or more fins 504. In the embodiment shown in FIG. 5, the liquid sample cell 500 has two fins 504 with different distances in the rotational axis direction (z-axis direction) from the lower surface. The fin 504 on the left side in FIG. 5 is at a position with a lower height from the film 502 surface than the fin 504 on the right side.

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

[0048] Also, in FIG. 5, the fin 504 is integrally formed with the cylindrical portion, but the cylindrical portion and the fin 504 may be formed individually and the fin 504 may be fitted into the cylindrical portion.

[0049] Further, it is desirable for the cylindrical portion and the fin 504 to be formed of the same material. By making the materials of the cylindrical portion and the fin 504 the same, the influence of noise other than the fluorescent X-ray emitted from the liquid sample to be analyzed on the analysis accuracy can be reduced.

[0050] The solid sample cell 600 houses the solid sample. Specifically, as shown in FIG. 6, the solid sample cell 600 has a substantially cylindrical shape with an opening in the entire upper surface and an opening smaller than the upper surface provided in the lower surface. The solid sample is housed between the upper surface and the lower surface. The solid sample is exposed from the opening provided in the lower surface. When analyzing a powdered solid sample, a film 502 may be provided at the opening in the lower surface.

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

[0052] The upper part of Figure 7 shows information representing the angle of measurement for fluorescent X-rays (the angle between the surface of the spectroscopic element described above and the direction of propagation of fluorescent X-rays incident on the detector 108). The middle part of Figure 7 shows information representing the rotation speed when the fluorescent X-ray analysis system 100 is operating in non-stirring measurement mode. The lower part of Figure 7 shows information representing the rotation speed when the fluorescent X-ray analysis system 100 is operating in stirring measurement mode.

[0053] The non-stirring measurement mode is a measurement mode in which a solid sample cell 600 is placed on the sample stage 102, and the detector 108 performs measurements while the rotation mechanism 104 rotates at a constant rotational speed under the control of the speed control unit 404. Specifically, the non-stirring measurement mode includes only the period of constant-speed rotation. First, the solid sample to be measured is placed in the solid sample cell 600 shown in Figure 6. The solid sample is exposed from the 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 at a constant rotation speed. As a result, the solid sample cell 600 rotates in the XY plane during the period from time t0 to time t1. Next, at time t1, the detector 108 starts measuring the X-ray fluorescence intensity at the peak angle of line A (arbitrary X-ray fluorescence). From time t1 to time t2, the detector 108 measures the X-ray fluorescence intensity at the said peak angle. Next, at time t2, the detector 108 stops measuring the X-ray fluorescence intensity. From time t2 to time t3, the detector 108 does not measure the X-ray fluorescence intensity. Next, at time t3, the detector 108 starts measuring the X-ray fluorescence intensity at the background angle of line A (arbitrary X-ray fluorescence). From time t3 to time t4, the detector 108 measures the X-ray fluorescence intensity at the said background angle. Then, after time t4, the analysis unit 402 analyzes the elements that produce fluorescent X-rays related to line A based on the fluorescent X-ray intensity at the peak angle and the fluorescent X-ray intensity at the background angle.

[0055] In non-stirring measurement mode, the rotation speed of the solid sample cell 600 is constant (e.g., 60 rpm). By rotating the surface of the solid sample irradiated with primary X-rays at a constant rotation speed, variations in analysis results due to surface irregularities of the solid sample can be reduced. Note that a constant rotation speed in non-stirring measurement mode means that the rotation speed is constant during the period when the detector 108 is measuring the intensity of fluorescent X-rays. That is, even during the period of operation in non-stirring measurement mode, the rotation speed may change during the period when the detector 108 is not measuring the intensity of fluorescent X-rays. For example, even during the period of operation in non-stirring measurement mode, the rotation speed may change during the period before the detector 108 starts measuring the intensity of 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 has finished measuring the intensity of fluorescent X-rays. Furthermore, the range of constant rotation speed is the range of rotation speed that can reduce variations in analysis accuracy due to surface irregularities of the solid sample. For example, even if the speed control unit 404 controls the rotation mechanism 104 to rotate at a constant rotational speed, the rotational speed of the rotation mechanism 104 may change due to given conditions (such as changes in temperature and humidity). Also, the rotational speed of the rotation mechanism 104 may change due to its characteristics (such as manufacturing variations and reliability). However, as long as the rotational speed is within a range that can reduce variations in analytical accuracy due to irregularities on the surface of the solid sample, any slight changes will fall within a certain range of rotational speed.

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

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

[0058] The post-stirring measurement period is the period during which the detector 108 performs measurements after the liquid sample has been stirred. Specifically, the detector 108 measures the intensity of fluorescent X-rays emitted from the sample during the post-stirring measurement period, which follows the stirring period. The speed control unit 404 may instruct the rotation mechanism 104 to rotate during the post-stirring measurement period. For example, 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 during the post-stirring measurement period. Alternatively, the speed control unit 404 may instruct the rotation mechanism 104 to stop during the post-stirring measurement period.

[0059] In the example shown in Figure 7, first, the liquid sample to be measured is placed in the liquid sample cell 500 shown in Figure 5. This liquid sample cell 500 is then placed on the sample stage 102.

[0060] Next, at time t0, the speed control unit 404 instructs the rotation mechanism 104 to rotate clockwise at a predetermined rotation speed (e.g., 60 rpm). As a result, the sample cell begins to rotate clockwise in the XY plane from time t0. Furthermore, after a predetermined time (e.g., 5 seconds) has elapsed, the speed control unit 404 instructs the rotation mechanism 104 to rotate counterclockwise at a predetermined rotation speed (e.g., -60 rpm). As a result, the sample cell begins to rotate counterclockwise in the XY plane. Note that the rotation speed may change discontinuously from 60 rpm to -60 rpm after a predetermined time has elapsed from time t0, or it may change continuously from 60 rpm to -60 rpm over a certain period of time. Time t1 and rotation speed are set to values ​​sufficient to stir the liquid sample.

[0061] The speed control unit 404 only needs to give an instruction to discontinuously change the rotation speed at least once during the stirring period, but it is desirable to give instructions multiple times. Specifically, for example, it is desirable for the speed control unit 404 to give an instruction to the rotation mechanism 104 to rotate alternately in the forward direction (e.g., rotation speed of 60 rpm) and in the reverse direction (e.g., rotation speed of -60 rpm) at regular intervals (e.g., 5 seconds). Alternatively, for example, the speed control unit 404 may give an instruction to the rotation mechanism 104 to rotate in the forward direction (e.g., rotation speed of 60 rpm) and an instruction to stop (rotation speed of 0 rpm) at regular intervals (e.g., 5 seconds). In the example shown in Figure 7, the period from time t0 to time t1 includes two periods of rotation in the forward direction and two periods of rotation in the reverse direction.

[0062] As the rotational speed of the liquid sample cell 500 changes, the liquid sample contained in the liquid sample cell 500 is agitated. Specifically, after the liquid sample cell 500 has been rotating at a constant speed for a sufficient amount of time, the liquid sample is rotating at the same speed as the liquid sample cell 500. In this state, the relative velocity between the cylindrical part and the liquid sample is 0. If the liquid sample were contained in a cylindrical liquid sample cell 500 without an agitator, when the rotational speed of the liquid sample cell 500 changes, the liquid sample would rotate at the previous rotational speed according to the law of inertia. However, since an agitator is provided in this disclosure, when the rotational speed of the liquid sample cell 500 changes, the liquid sample near the agitator is prevented from rotating at the rotational speed according to the law of inertia by the agitator. As a result, turbulence occurs in the flow of the liquid sample starting from the agitator, and the liquid sample is agitated.

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

[0064] At time t1, the liquid sample is thoroughly stirred. Therefore, whether or not to rotate the rotation mechanism 104 during the post-stirring measurement period is set appropriately depending on whether or not the settling components contained in the liquid sample 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 rotation in the forward direction and one period of rotation in the reverse direction. Furthermore, the forward and reverse rotation speeds during the post-stirring measurement period are half of the forward and reverse rotation speeds during the stirring period.

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

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

[0067] Then, after time t4, the analysis unit 402 analyzes the elements that produce fluorescent X-rays related to 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 this disclosure, by using a rotating mechanism 104 to reduce the influence of the surface roughness of the solid sample, it is possible to suppress an increase in manufacturing costs, while reducing the influence on the measurement results due to the sedimentation of settling components by having a stirring section in the liquid sample cell 500.

[0069] This disclosure may be applied to either wavelength-dispersive or energy-dispersive X-ray fluorescence analysis systems 100. Furthermore, it is not limited to the above embodiments, and various modifications are possible. The configuration of the X-ray fluorescence analysis system 100 described above is an example and is not limited thereto. It may be replaced with a configuration that is substantially the same as the configuration shown in the above embodiments, a configuration that produces the same effects, or a configuration that achieves the same purpose. For example, in Figure 7, the length and number of stirring periods are predetermined. However, the configuration may be such that the length and number of stirring periods vary based on the analysis results.

[0070] Figure 8 is a flowchart showing the operation of the X-ray fluorescence analysis system 100 in the stirring measurement mode according to the second embodiment. In the second embodiment, we will describe a case where only the intensity at the peak angle is measured and the background intensity near the peak angle is not measured. First, a preliminary measurement is performed before stirring (S802). As an initial value, the variable n, which represents the number of stirring cycles, is set to 0.

[0071] Specifically, first, the 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, primary X-rays are irradiated onto the liquid sample, and the detector 108 measures the intensity of the fluorescent X-rays generated from the liquid sample. The intensity measured at S802 is denoted as I0.

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

[0073] Next, a preliminary measurement is performed after stirring (S806). As will be described later, steps S804-S814 are repeated. S806 is a step in which the detector 108 measures the intensity of fluorescent X-rays during the nth post-stirring measurement period, and when n is 1, it is the first post-stirring measurement period. Step S806 is the same as one post-stirring measurement period shown in Figure 7. The detector 108 measures the intensity of fluorescent X-rays emitted from the liquid sample. The intensity measured in S806 is denoted as I1.

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

[0075] Next, 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, it is determined whether or not to set the (n+2)th stirring period (S810). Specifically, the (n+2)th stirring period is set if 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. For example, if n is 1, intensity I0 is the intensity measured in S802. Also, the intensity of the fluorescent X-rays measured during the first post-stirring measurement period is intensity I1, measured in S806. The difference between intensity I0 and intensity I1 is the theoretical intensity standard deviation σI1. calc If the specified magnification α is less than the specified magnification, the process proceeds to S816; otherwise, it proceeds to S812. The specified magnification α is a pre-set value.

[0076] In S812, it is determined whether the number of stirring cycles n is greater than or equal to a preset maximum number of stirring cycles. If the number of stirring cycles n is greater than the maximum number of stirring cycles, the process proceeds to S816; otherwise, it proceeds to S814. The maximum number of stirring cycles can be set to any value, but for example, it is 10.

[0077] In S814, the value of intensity I0 is set to intensity I1. Specifically, if the number of stirring cycles n is 1, the value of intensity I0 is set to the intensity I1 measured in the first S806. Then, the process proceeds back to S804.

[0078] If it is determined in S810 and S812 to proceed to S816, this measurement is performed (S816). The step in S816 is the same as one post-stirring measurement period shown in Figure 7.

[0079] According to the second embodiment, the stirring measurement mode alternately includes a stirring period and a post-stirring measurement period. It also includes the steps of: measuring the intensity of fluorescent X-rays with the detector 108 during the nth post-stirring measurement period; measuring the intensity of fluorescent X-rays with the detector 108 during the (n+1)th post-stirring measurement period; and determining whether or not 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 a liquid sample is thoroughly stirred, the difference between intensity I0 and intensity I1 is equal to the theoretical intensity standard deviation σI1. calc It becomes smaller than the specified magnification α. ​​On the other hand, if the liquid sample is not sufficiently stirred, the difference between intensity I0 and intensity I1 is equal to the theoretical intensity standard deviation σI1. calc The magnification becomes greater than the specified magnification α. ​​According to the second embodiment, the sample can be analyzed after a sufficient number of stirring periods.

[0081] [Modification 1] Figure 9 is 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 opening at the top and a lid portion 902 that fits into the opening. The fins 504 are formed integrally with the lid portion 902. Specifically, the lid portion 902 has a disc-shaped portion that covers the opening at the top of the cylindrical portion, two columnar portions that extend substantially vertically from the disc-shaped portion, and fins 504 (stirring portions) provided on each of the two columnar portions. The lid portion 902 fits into the cylindrical portion by arranging the two columnar portions at a distance equal to the inner diameter of the cylindrical portion. In the example shown in Figure 9, the fins 504 are provided at the same height and have the same shape as in the first and second embodiments. The cylindrical portion and the film 502 are the same as in the first and second embodiments.

[0082] According to Modification 1, the possibility of liquid sample leakage can be reduced by providing the lid portion 902. Furthermore, since the cylindrical portion and film 502 in Modification 1 are the same as those used in conventional configurations, the lid portion 902 alone can be manufactured and used in combination with conventional configurations.

[0083] [Modification 2] Figure 10 is a top view and a cross-sectional view of the liquid sample cell 500 according to Modification 2. Modification 2 may be applied to either the first embodiment or the 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 accommodating the sample, similar to the cylindrical portion.

[0084] The rectangular parallelepiped cylindrical portion 1002 includes an outer member 506 and an inner member 508. The outer member 506 and the inner member 508 have a substantially 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, covering the lower opening of the inner member 508. The liquid sample to be analyzed by the X-ray fluorescence analysis system 100 is placed in the space enclosed by the inner member 508. Because the inner member 508 is substantially rectangular parallelepiped, the housing space of the liquid sample cell 500 has a substantially rectangular parallelepiped shape.

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

[0086] In Modification 2, the corner portion of the inner member 508 and the two fins 504 function as stirring sections. That is, when the rotational speed of the liquid sample cell 500 changes, the liquid sample near the corner portion is prevented from rotating at a speed according to the law of inertia. As a result, when the rotational speed of the liquid sample cell 500 changes, turbulence occurs in the flow of the liquid sample starting from the stirring section, and the liquid sample is stirred. Therefore, stirring can be achieved in a shorter time than in the first and second embodiments. It is desirable to provide the fins 504 in Modification 2 as well, but the fins 504 in Modification 2 may be omitted.

[0087] [Modification 3] Figure 11 is a top view and a cross-sectional view of the 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 embodiment shown in Figure 5 in that the height of the fins 504 is different, and all other aspects are the same. As shown in Figure 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 with which sedimentary components in the sample settle, etc. Also, similar to the above, the shape of the fins 504 does not have to be rectangular.

[0088] [Modification 4] Figure 12 is a top view and a cross-sectional view of the sample cell according to Modification 4. Modification 4 may be applied to either the first or second embodiment. The difference from the embodiment shown in Figure 5 is that the liquid sample cell 500 is sized to fit inside the solid sample cell 600, but other aspects are the same. When analyzing a liquid sample in Modification 4, the liquid sample cell 500 containing the liquid sample is placed in the housing space of the solid sample cell 600, and the solid sample cell 600 is placed on the sample stage 102. On the other hand, when analyzing a solid sample, the solid sample is placed in the housing space of the solid sample cell 600, and the solid sample cell 600 is placed on the sample stage 102. In Modification 4 as well, the two fins 504 may be of 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. That is, it is not necessary to make the sample stage 102 shaped to accommodate two different types of sample cells. Furthermore, the device for transporting sample cells included in the conventional X-ray fluorescence analysis system 100 can be reused. Therefore, the configuration can be simplified and the increase in manufacturing costs can be suppressed.

[0090] 100 X-ray fluorescence analysis system, 102 sample stage, 104 rotation mechanism, 106 X-ray source, 108 detector, 300 information processing device, 302 calculation unit, 304 storage unit, 306 display unit, 308 input / output unit, 310 internal bus, 402 analysis unit, 404 speed control unit, 500 liquid sample cell, 502 film, 504 fin, 506 outer member, 508 inner member, 600 solid sample cell, 902 lid, 1002 rectangular cylindrical part.

Claims

1. A fluorescent X-ray analysis system comprising: a sample stage on which a sample cell having a storage space for containing a sample is placed and which has an opening that exposes the lower surface of the sample cell; a rotation mechanism for rotating 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 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 includes: a liquid sample cell in which a liquid sample is contained and the cross-section of the storage space parallel to the lower 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 contained, and a stirring measurement mode comprising: a non-stirring measurement mode in which the detector performs measurements while the rotation mechanism is rotating at a constant rotation speed under the control of the speed control unit; a stirring period in which the liquid sample is stirred by the speed control unit rotating the rotation mechanism at a changing rotation speed; and a post-stirring measurement period in which the detector performs measurements after the liquid sample has been stirred, A fluorescence X-ray analysis system characterized by operating in an operating mode that includes a specific feature.

2. The X-ray fluorescence analysis system according to claim 1, characterized in that the sample stage is capable of holding the liquid sample cell and the solid sample cell, the solid sample cell is placed on the sample stage in the non-stirring measurement mode, and the liquid sample cell is placed on the sample stage in the stirring measurement mode.

3. The X-ray fluorescence analysis system according to claim 1 or 2, characterized in that the containment space of the liquid sample cell has a substantially cylindrical shape, and the liquid sample cell has one or more fins having a predetermined length in the radial direction and rotational axis direction of the containment space.

4. The fluorescent X-ray analysis system according to claim 3, characterized in that the liquid sample cell has a cylindrical portion with an open top and a lid portion that fits into the opening, and the fins are integrally formed with the lid portion.

5. The fluorescent X-ray analysis system according to claim 3, characterized in that the liquid sample cell has a cylindrical portion with an open top surface, and the fins are integrally formed with the cylindrical portion.

6. The fluorescent X-ray analysis system according to claim 3, characterized in that the liquid sample cell has a cylindrical portion with an open top, the cylindrical portion and the fin are formed separately, and the fin is fitted into the cylindrical portion.

7. The fluorescent X-ray analysis system according to claim 4, characterized in that the cylindrical portion and the fins are formed from the same material.

8. The fluorescent X-ray analysis system according to claim 1 or 2, further comprising the liquid sample cell.

9. The fluorescent X-ray analysis system according to claim 1, characterized in that the speed control unit instructs the rotation mechanism to discontinuously change the rotation speed during the stirring period.

10. The fluorescent X-ray analysis system according to claim 1 or 9, characterized in that the speed control unit instructs the rotation mechanism to rotate in the forward direction for a predetermined time during the stirring period, and then instructs it to rotate in the reverse direction.

11. The fluorescent X-ray analysis system according to claim 1 or 9, characterized in that the speed control unit gives an instruction to stop the rotation mechanism during the post-stirring measurement period.

12. The fluorescent X-ray analysis system according to claim 1 or 9, characterized in that the speed control unit gives an instruction to rotate the rotation mechanism during the post-stirring measurement period.

13. The fluorescent X-ray analysis system according to claim 12, characterized in that the speed control unit, during the post-stirring measurement period, instructs the rotation mechanism to rotate in the forward direction for a predetermined time, and then instructs it to rotate in the reverse direction.

14. A non-temporary computer-readable information storage medium for storing a fluorescent X-ray analysis program executed on a computer used in a fluorescent X-ray analysis system, wherein the fluorescent X-ray analysis system comprises: a sample stage on which a sample cell having a storage space for a sample is placed and which has an opening that exposes the lower surface of the sample cell; a rotation mechanism for rotating 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 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 comprises: a liquid sample cell in which a liquid sample is placed and the cross-section of the storage space parallel to the lower 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 placed, wherein the fluorescent X-ray analysis program comprises: a non-stirred measurement mode in which the detector performs measurements while the rotation mechanism is rotating at a constant rotation speed under the control of the speed control unit; An information storage medium characterized in that it causes the computer to execute an operating mode that includes: a stirring measurement mode, which includes a stirring period in which the speed control unit stirs the liquid sample by rotating the rotation mechanism at a changing rotational speed; and a post-stirring measurement period in which the detector performs measurements after the liquid sample has been stirred.

15. The information storage medium according to 14, wherein the stirring measurement mode alternately includes the stirring period and the post-stirring measurement period, and the fluorescent X-ray analysis program, when executing the stirring measurement mode, causes the computer to perform the following steps: the step of the detector measuring the intensity of fluorescent X-rays during the nth post-stirring measurement period; the step of the detector measuring the intensity of fluorescent X-rays during the (n+1)th post-stirring measurement period; and the step of determining whether or not 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.

16. The information storage medium according to claim 15, characterized in that, in the step of making the determination, if the difference or ratio between 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 is greater than a predetermined value, the (n+2)th stirring period is set.

17. A liquid sample cell used in the X-ray fluorescence analysis system according to claim 1, characterized in that the containment space of the liquid sample cell has a substantially cylindrical shape, and the liquid sample cell has one or more fins having a predetermined length in the radial and axial directions of the containment space.

18. The liquid sample cell according to claim 17, characterized in that the liquid sample cell has a cylindrical portion with an open top surface, the cylindrical portion and the fin are formed separately, and the fin is fitted into the cylindrical portion.

19. The liquid sample cell according to claim 17 or 18, characterized in that the cylindrical portion and the fins are formed of the same material.

20. A fluorescent X-ray analysis program executed by a computer used in a fluorescent X-ray analysis system comprising: a sample stage on which a sample cell having a storage space for containing a sample is placed and which has an opening that exposes the lower surface of the sample cell; a rotation mechanism for rotating 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 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 comprises: a liquid sample cell in which a liquid sample is contained and the cross-section of the storage space parallel to the lower 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 contained, and a non-stirred measurement mode in which the detector performs measurements while the rotation mechanism rotates at a constant rotation speed under the control of the speed control unit, A fluorescent X-ray analysis program characterized by causing the computer to execute an operation mode that includes: a stirring measurement mode, which includes a stirring period in which the speed control unit stirs the liquid sample by rotating the rotation mechanism at a variable rotational speed; and a post-stirring measurement period in which the detector performs measurements after the liquid sample has been stirred.

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