Fluorescent x-ray analysis device

Abstract

This fluorescent X-ray analysis device (1000) comprises an adjustment mechanism (4A), an X-ray tube (2), a detector (3), and a control device (9). A first path (11A) has a first portion (110A) where a liquid sample (S) is exposed and flows. The adjustment mechanism (4A) adjusts the flow rate of the liquid sample (S) flowing through the first path (11A). The X-ray tube (2) irradiates the liquid sample (S) with primary X-rays in the first portion (110A). The detector (3) detects fluorescent X-rays generated from the liquid sample (S) by means of the primary X-rays. The control device (9) analyzes the fluorescent X-rays detected by the detector (3). The detector (3) is disposed at a position where the fluorescent X-rays generated from the liquid sample (S) are directly incident. The adjustment mechanism (4A) adjusts the flow rate of the liquid sample (S) such that the position of the surface (58A) of the liquid sample (S) in the first portion (110A) is kept constant.

Description

X-ray fluorescence analyzer

[0001] The present disclosure relates to an X-ray fluorescence analyzer, and more particularly to improving the efficiency of light element analysis of liquid samples.

[0002] In an energy dispersive X-ray fluorescence spectrometry (EDX) analyzer, a sample is analyzed by irradiating the sample with a primary X-ray source emitted from an X-ray source and analyzing the fluorescent X-rays emitted from the sample.

[0003] Conventionally, when measuring a liquid sample using EDX, a known method involves, for example, placing the liquid sample in a container with a film-covered underside, irradiating it with primary X-rays from below, and detecting fluorescent X-rays. Japanese Patent Laid-Open Publication No. 10-197460 (Patent Document 1) discloses a technique in which X-rays are irradiated and detected through a thin film in a flow cell through which the liquid sample flows.

[0004] Japanese Patent Laid-Open No. 10-197460 Japanese Patent Laid-Open No. 2005-024300 Japanese Patent Laid-Open No. 2005-172719

[0005] However, in the technique of irradiating and detecting fluorescent X-rays through a film as described above, the fluorescent X-rays of light elements tend to be absorbed by the film during light element analysis, resulting in insufficient intensity and reduced sensitivity.

[0006] On the other hand, a technique has also been known in which a liquid sample is placed in a container, the liquid surface is irradiated with primary X-rays from above, and fluorescent X-rays are detected. However, with this method, the height of the liquid surface changes depending on the amount of liquid sample, so it is necessary to readjust the positions of the optical system, including the X-ray tube and detector, depending on the amount of liquid sample. Another technique involves soaking filter paper in the liquid sample, irradiating the filter paper with primary X-rays, and detecting fluorescent X-rays, but this requires the effort of soaking the filter paper in the liquid sample.

[0007] Therefore, there has been a demand for an X-ray fluorescence analyzer that can easily and sensitively analyze light elements in liquid samples.

[0008] The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide an X-ray fluorescence analysis apparatus for liquid samples.

[0009] A first aspect of the present invention is an X-ray fluorescence analysis apparatus comprising a first path, an adjustment mechanism, an X-ray tube, a detector, and a control device. The first path has a first portion through which a liquid sample flows exposed. The adjustment mechanism adjusts the flow rate of the liquid sample flowing through the first path. The X-ray tube irradiates the liquid sample with primary X-rays in the first portion. The detector detects fluorescent X-rays generated from the liquid sample by the primary X-rays. The control device analyzes the fluorescent X-rays detected by the detector. The detector is positioned at a position where the fluorescent X-rays generated from the liquid sample directly enter. The adjustment mechanism adjusts the flow rate of the liquid sample so that the position of the surface of the liquid sample in the first portion is kept constant.

[0010] According to the present disclosure, it is possible to provide an X-ray fluorescence analyzer that performs light element analysis of a liquid sample easily and with high sensitivity.

[0011] Fig. 3 is a schematic diagram showing the configuration of an analysis device according to embodiment 1. Fig. 4 is a diagram for explaining the positional relationship between the X-ray tube, detector, and liquid sample in Fig. 1. Fig. 5 is a schematic diagram showing the configuration of a measurement device according to embodiment 2. Fig. 6 is a diagram for explaining the positional relationship between the X-ray tube, detector, and liquid sample in Fig. 3. Fig. 7 is a diagram for explaining another example of the adjustment mechanism in Fig. 3.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0013] 1 is a schematic diagram showing the configuration of an analytical device 1000 according to embodiment 1. The analytical device 1000 corresponds to an example of an "X-ray fluorescence analyzer." The analytical device 1000 according to embodiment 1 includes a measuring device 10A and a control device 9.

[0014] (1. Schematic Configuration of the Measuring Apparatus) The measuring apparatus 10A includes a circulation path 1A, an X-ray tube 2, and a detector 3. The circulation path 1A is a path for circulating a liquid sample S. In the circulation path 1A, the liquid sample S is driven by a pump 41A (described later) and circulated in the directions indicated by arrows AR1 to AR4.

[0015] 1, the direction in which the liquid sample S flows in the first path 11A (see arrow AR1) described later is defined as the negative Z-axis direction, and the direction in which the liquid sample S flows in the buffer path 121A (see arrow AR2) described later is defined as the positive Y-axis direction. The direction perpendicular to the Y-axis and Z-axis is defined as the X-axis direction. The measurement device 10A is used in a state where it is installed so that the negative Z-axis direction roughly coincides with the direction of gravity.

[0016] The X-ray tube 2 includes a filament that emits thermoelectrons and a target that converts the thermoelectrons into predetermined primary X-rays and emits them. The primary X-rays emitted from the X-ray tube 2 are irradiated onto the liquid sample S flowing through the circulation path 1A (see arrow 51A). Secondary X-rays (fluorescent X-rays) generated from the liquid sample S are directly incident on the detector 3 (see arrow 52A), and the energy and amount of the fluorescent X-rays are measured by the detector 3. More specifically, the amount of X-rays is generally expressed as the number of X-ray photons per unit time. The amount of X-rays is also referred to as X-ray intensity. The energy of X-rays is generally expressed as the wavelength of the X-rays. The detection result of the detector 3 is typically expressed as an X-ray fluorescence spectrum, which shows the relationship between the energy and amount of the detected fluorescent X-rays.

[0017] The measurement apparatus 10A may include a primary X-ray filter (not shown) that improves the S / N ratio of required characteristic X-rays by attenuating background components of the primary X-rays emitted from the X-ray tube 2. In this case, the primary X-rays that have been emitted from the X-ray tube 2 and then transmitted through the primary X-ray filter are irradiated onto the liquid sample S.

[0018] The measurement device 10A may also include a collimator (not shown) that determines the size of the primary X-ray beam. In this case, the primary X-rays are emitted from the X-ray tube 2 and then pass through a through-hole formed in the center of the collimator, and are then irradiated onto the liquid sample S.

[0019] (2. Configuration of the Control Device) The control device 9 controls the measurement device 10A and analyzes the fluorescent X-rays detected by the detector 3. It includes a processor 90, a memory 91, an input device 92, and an output device 93. The control device 9 can be, for example, a personal computer.

[0020] The processor 90 includes, for example, a CPU (Central Processing Unit).

[0021] The memory 91 is realized by a storage device such as a read only memory (ROM), a random access memory (RAM), or a hard disk drive (HDD).

[0022] The input device 92 includes, for example, at least one of a keyboard, a mouse, a touch panel, a button, and a knob.

[0023] The output device 93 includes, for example, a display or a speaker. During measurement, the control device 9 acquires the fluorescent X-ray spectrum detected by the detector 3. The control device 9 performs quantitative analysis of each element based on the fluorescent X-ray spectrum. In the fluorescent X-ray spectrum, fluorescent X-ray peaks appear at energy positions specific to each element. By examining the peak positions and peak intensities of the fluorescent X-ray spectrum, the energy and amount of the fluorescent X-rays can be determined, making it possible to identify the types and amounts of elements contained in the liquid sample S.

[0024] The control device 9 controls the X-ray tube 2, the detector 3, and the adjustment mechanism 4A (described later). This allows the X-ray tube 2 and the detector 3 to perform X-ray fluorescence analysis of the liquid sample S flowing through the first path 11A while the adjustment mechanism 4A keeps the state of the liquid sample S flowing through the first path 11A constant.

[0025] (3. Circulation Path) Next, the circulation path 1A will be described in detail.

[0026] The circulation path 1A includes a first path 11A, a second path 12A, and an adjustment mechanism 4A. The first path 11A is formed at a position where the liquid sample S flows due to gravity. The second path 12A is a path for returning the liquid sample S that has flowed out of the first path 11A back to the first path. The first path 11A and the second path 12A form the circulation path 1A. A first opening 111A is an opening of the second path 12A that serves as an inlet for the liquid sample S into the first path 11A and an outlet for the second path 12A through which the liquid sample S flows out. A second opening 112A is an inlet for the liquid sample S into the second path 12A and an outlet for the liquid sample S through which the liquid sample S flows out of the first path 11A. The first opening 111A and the second opening 112A are each a junction between the first path 11A and the second path 12A.

[0027] 1, the first path 11A is formed along the direction of gravity (along the negative Z-axis direction), and the second opening 112A is configured to be located directly below the first opening 111A.

[0028] The first path 11A has a first portion 110A through which the liquid sample S flows and is exposed to the space of the measurement device 10A. In the example of Fig. 1, the first portion 110A is between the first opening 111A and the second opening 112A.

[0029] With the above configuration, the liquid sample S discharged from the first opening 111A falls through the first path 11A along the negative direction of the Z axis and then returns to the second path 12A through the second opening 112A. The liquid sample S that returned to the second path 12A is then pumped up by the pump 41A and flows again into the first path 11A through the first opening 111A. This allows the liquid sample S continuously flowing through the first portion 110A to be directly irradiated with primary X-rays generated from the X-ray tube 2, and fluorescent X-rays generated from the liquid sample S by the primary X-rays to directly enter the detector 3. Therefore, the primary X-rays can be irradiated onto the liquid sample S without being attenuated by a thin film or the like, and the fluorescent X-rays can reach the detector 3 without being attenuated by a thin film or the like.

[0030] In this specification, "directly" irradiating / incidentally irradiating X-rays means that the X-rays are irradiated / incident without passing through an object constituting the measurement device 10A. However, this object does not include a primary X-ray filter that removes primary X-rays with wavelengths of energy unnecessary for analysis. This object also does not include holes in a member such as a collimator that narrows the irradiation diameter of primary X-rays by passing them through holes. Therefore, for example, the expression "directly" irradiating / incidentally irradiating X-rays both includes cases where X-rays are irradiated / incident through a filter member and cases where X-rays are irradiated / incident by passing through holes in a collimator or the like.

[0031] (4. Adjustment Mechanism) Next, the adjustment mechanism 4A will be described in detail with reference to Figures 1 and 2. Figure 2 is a diagram for explaining the positional relationship between the X-ray tube 2, the detector 3, and the liquid sample S as viewed from the Z-axis direction.

[0032] The adjustment mechanism 4A is a mechanism that defines the first path 11A through which the liquid sample S flows and maintains a constant state of the liquid sample in the first path 11A. More specifically, the adjustment mechanism 4A adjusts the flow rate of the liquid sample S flowing through the first path 11A so that the position of the surface 58A of the liquid sample S in the first portion 110A is maintained constant. The position of the surface 58A is the position of the boundary between the liquid sample S and the space surrounding the liquid sample S.

[0033] Referring to FIG. 1, the adjustment mechanism 4A includes a pump 41A and an outlet mechanism 42A that forms a first opening 111A that is an outlet for the liquid sample S from the second path 12A.

[0034] By driving the pump 41A, the liquid sample S that has flowed in from the second opening 112A is returned to the first opening 111A, which is located in the positive direction of the Z axis from the second opening 112A. The pump 41A also adjusts the position of the surface 58A of the liquid sample S by adjusting the flow rate of the liquid sample S in the first path 11A.

[0035] The outlet mechanism 42A is a mechanism surrounding the first opening 111A. The outlet mechanism 42A adjusts the position of the surface 58A of the liquid sample S by adjusting the flow rate of the liquid sample S in the first path 11A.

[0036] In the measurement device 10A according to the first embodiment, the pump 41A and / or the outlet mechanism 42A are adjusted to keep the position of the surface 58A of the liquid sample S falling through the first path 11A constant. Therefore, the adjustment mechanism 4A can adjust the position of the surface 58A of the liquid sample S falling through the first path 11A to be constant.

[0037] The discharge volume / discharge pressure of the pump 41A and the opening diameter / opening area of ​​the outlet mechanism 42A are set so that the focal point 50A between the X-ray tube 2 and the detector 3 is located on the surface 58A. In one embodiment, the intersection (focal point 50A) of the arrow 51A, which is the center line of the irradiation range 53A of the primary X-ray beam emitted from the X-ray tube 2, and the arrow 52A, which is the center line of the detection area 54A of the detector 3, is set so that it is on the surface 58A. With this configuration, primary X-rays can be irradiated onto the surface 58A, and fluorescent X-rays generated from the surface 58A can be detected. Therefore, fluorescent X-rays generated from light elements in the liquid sample S can be detected with sufficient intensity without being attenuated within the liquid sample S. Therefore, light elements in the liquid sample S can be analyzed with high sensitivity.

[0038] The positions of the X-ray tube 2 and the detector 3 may be set so that the focus is formed a predetermined distance inward from the surface 58A of the liquid sample S, as long as the fluorescent X-rays from the light elements can be detected with sufficient intensity.

[0039] (5. Other Aspects of the Measurement Device) The configuration of the first path 11A is not limited to the example shown in FIG. 1 , and it is sufficient that the surface 58A of the first portion 110A is exposed on the side where primary X-rays are irradiated and fluorescent X-rays are detected (the side of the focal point 50A in FIG. 2 ). For example, in FIG. 2 , the entire periphery of the first path 11A is exposed according to its entire length, but a portion of the first path 11A in the Z-axis direction may be covered with a pipe, a thin film, or the like. Furthermore, a portion of the side of the first portion 110A where primary X-rays are not irradiated (for example, the side opposite the focal point 50A in FIG. 2 ) may be covered with a pipe, a thin film, or the like. However, it is preferable that the entire periphery of the first portion 110A be exposed in order to reduce the possibility of impurity rays being generated from the pipe or thin film.

[0040] Furthermore, the first path 11A may be formed so that the liquid sample flows obliquely with respect to the direction of gravity, as long as the height of the surface 58A at the position where the focal point 50A is formed is adjusted to be constant. Specifically, for example, a gutter-shaped member may be provided that is obliquely placed with respect to the direction of gravity, and the liquid sample S may flow through the gutter-shaped member.

[0041] 1, the configuration of the second path 12A is not limited to that shown in FIG. 1, and any configuration is possible as long as it can circulate the liquid sample S through the first path 11A. In the example shown in FIG. 1, the second path 12A is covered by the pipe 8A, but a portion of the second path 12A may be exposed to the surrounding atmosphere as long as the liquid sample S does not leak from that portion.

[0042] The specific configuration of the adjustment mechanism 4A is not particularly limited as long as it can maintain a constant position of the surface 58A of the liquid sample S flowing through the first path 11A. For example, the pump 41A may be a pump with a fixed rotation speed or a pump with a variable rotation speed. Furthermore, the portion of the outlet mechanism 42A through which the liquid sample S passes may be a member including a fixed hole or a variable valve whose opening degree is variable.

[0043] The amount of liquid sample S contained in circulation path 1A may vary for each measurement. Even when the amount of liquid sample S changes for each measurement, the position of surface 58A in first portion 110A can be maintained at a predetermined position including focal point 50A by adjusting the state of adjustment mechanism 4A.

[0044] Preferably, a portion of the second path 12A includes a path that serves as a buffer for the liquid sample S flowing into the first path 11A. For example, in the example of Fig. 1, the buffer path 121A is between the second opening 112A and a junction 122A that connects the second path 12A and the pump 41A. The buffer path 121A can temporarily store excess liquid sample S in order to maintain the flow rate of the liquid sample S in the first path 11A at a predetermined value. Instead of the buffer path 121A, a tank that branches off from the second path 12A and can temporarily store excess liquid sample S may be provided.

[0045] The measurement device 10A may include a sensor (not shown) that detects the position of the surface 58A or a sensor (not shown) that detects the flow rate of the liquid sample S in the first path 11A. Furthermore, feedback control or feedback to the user may be performed based on the detection signal of the sensor. Specifically, based on the detection signal, the adjustment mechanism 4A (e.g., the rotation speed of the pump 41A) may be adjusted or a warning may be displayed to the user.

[0046] When light element analysis of a liquid sample S is performed using the measurement device 10A, it is preferable that the space between the liquid sample S and the detector 3 is a helium atmosphere rather than an air atmosphere. With this configuration, fluorescent X-rays generated from light elements can be detected by the detector 3 without being attenuated in the air.

[0047] [Comparison with conventional EDX] Conventionally, two types of EDX have generally been used: a bottom-illumination type in which a sample is placed above an optical system such as an X-ray tube and a detector, and fluorescent X-ray analysis is performed on the sample from below, and a top-illumination type in which a sample is placed below the optical system, and fluorescent X-ray analysis is performed on the sample from above.

[0048] When measuring a liquid sample using bottom-illumination EDX, for example, the liquid sample is placed in a container with a film on the bottom, the liquid sample is irradiated with primary X-rays through the film, and the fluorescent X-rays that pass through the film are detected. However, when light element analysis of a liquid sample is performed, the fluorescent X-rays of the light elements are absorbed by the film, preventing the acquisition of fluorescent X-rays of sufficient intensity and resulting in a decrease in sensitivity.

[0049] To avoid this problem, a technique using filter paper to soak the liquid sample is known, but this requires prior preparation by soaking the filter paper in the liquid sample prior to analysis. Furthermore, if a large amount of liquid sample is soaked in the filter paper, the liquid sample may leak from the filter paper and affect the X-ray tube and / or detector. On the other hand, if the amount of liquid sample soaked in the filter paper is small, the detection sensitivity decreases. Thus, even when using filter paper, there is a high possibility of problems with liquid sample preparation.

[0050] On the other hand, when measuring a liquid sample using top-side EDX, it is necessary to appropriately set the distance between the X-ray tube and detector and the surface (liquid level) of the liquid sample contained in the container. For example, if the focal points of the X-ray tube and detector are located at a predetermined distance above the liquid level and not within the liquid sample, the liquid sample will not be irradiated with primary X-rays from the X-ray tube, and naturally, the primary X-rays will not generate fluorescent X-rays from the sample. Therefore, when measuring a liquid sample using top-side EDX, a mechanism (such as a mechanism for performing laser measurement) is required to measure the distance between the X-ray tube and detector and the surface of the liquid sample contained in the container. In addition, a mechanism is required to adjust the distance between the X-ray tube and detector and the surface of the liquid sample contained in the container. This can lead to the complexity of the X-ray fluorescence analyzer.

[0051] In relation to this, Patent Document 1, Japanese Patent Laid-Open No. 2005-024300 (Patent Document 2), and Japanese Patent Laid-Open No. 2005-172719 (Patent Document 3) disclose a technique in which a flow cell is provided through which a liquid sample flows, primary X-rays are irradiated through a thin film of the flow cell, and fluorescent X-rays are detected. However, even with this method, it is not possible to directly detect fluorescent X-rays emitted from the sample.

[0052] Therefore, the X-ray fluorescence analyzer according to this embodiment and its modifications includes a path for flowing a liquid sample, and controls the surface position of the liquid sample flowing in the path to be kept constant. Primary X-rays are then irradiated onto the liquid surface, which is kept constant, and fluorescent X-rays from the liquid surface are detected. This prevents the fluorescent X-rays emitted from the light elements from being absorbed by a film, and light element analysis of a liquid sample can be performed easily and with high sensitivity without prior preparation such as soaking the liquid sample in filter paper or providing a mechanism for moving the X-ray tube, detector, or liquid sample up and down or left and right.

[0053] Furthermore, in the X-ray fluorescence analyzers according to this embodiment and its modifications, the liquid sample is circulated through a circulation path, allowing the liquid sample to be repeatedly passed through the first path where X-ray fluorescence analysis is performed. Therefore, compared to analysis performed while the sample is flowing through a non-circulation path, fluorescent X-rays of sufficient intensity can be detected even with a small amount of sample. Furthermore, circulating the liquid sample reduces the possibility of precipitation occurring in the liquid sample during measurement, which could affect the analysis.

[0054] [Embodiment 2] (1. Schematic Configuration of Measuring Apparatus) Fig. 3 is a schematic diagram showing the configuration of a measuring apparatus 10B according to embodiment 2. In measuring apparatus 10B, a circulation path 1B is provided instead of circulation path 1A of measuring apparatus 10A. In measuring apparatus 10B, fluorescent X-ray analysis is performed on a liquid sample S flowing horizontally (see arrow AR8) in a first path 11B, which is part of circulation path 1B.

[0055] The measuring device 10B includes a circulation path 1B, an X-ray tube 2, and a detector 3. The circulation path 1B is a path for circulating a liquid sample S. In the circulation path 1B, the liquid sample S is circulated in the directions indicated by arrows AR5 to AR8 by a pump 41B, which will be described later.

[0056] (2. Circulation Path) The circulation path 1B includes a first path 11B, a second path 12B, and an adjustment mechanism 4B. The first path 11B is a path along which the liquid sample S flows horizontally. The second path 12B is a path for returning the liquid sample S that has flowed out of the first path back to the first path. The first path 11B and the second path 12B are connected by a first opening 111B and a second opening 112B to form the circulation path 1B.

[0057] The first path 11B has a first portion 110B through which the liquid sample S flows, exposed to the space of the measurement device 10B. In the example of FIG. 3 , in the first path 11B, the liquid sample S flows through a gutter-shaped member 81B that is open at the top, as shown in FIG. 4 . The gutter-shaped member 81B is, for example, a member obtained by cutting a pipe with a rectangular or circular cross section in half in the extension direction. In other words, in the first path 11B, a surface 58B of the liquid sample S in the positive Z-axis direction is exposed to the atmosphere inside the measurement device 10B. In the example of FIG. 3 , the first portion 110B corresponds to the portion between the first opening 111B and the second opening 112B.

[0058] With the above configuration, the liquid sample S discharged from the first opening 111B flows horizontally through the first path 11B (see arrow AR8) and then returns to the second path 12B through the second opening 112B. The liquid sample S that returned to the second path 12B is then pumped up by the pump 41B and flows again into the first path 11B through the first opening 111B. This allows the liquid sample S continuously flowing through the first portion 110B to be directly irradiated with primary X-rays generated from the X-ray tube 2, and allows fluorescent X-rays generated from the liquid sample S to directly enter the detector 3. This allows the liquid sample S to be irradiated with primary X-rays without being attenuated by a thin film or the like, and allows the fluorescent X-rays to reach the detector 3 without being attenuated by a thin film or the like.

[0059] (3. Adjustment Mechanism) The adjustment mechanism 4B is a mechanism that defines the first path 11B through which the liquid sample S flows and maintains a constant state of the liquid sample in the first path 11B. More specifically, the adjustment mechanism 4B adjusts the flow rate of the liquid sample S flowing through the first path 11B so that the position of a surface 58B, which is the liquid level of the liquid sample S in the first portion 110B, is maintained constant. The position of the surface 58B is the position of the boundary between the liquid sample S and the space surrounding the liquid sample S.

[0060] 1, the adjustment mechanism 4B includes a pump 41B and a valve 43B. By driving the pump 41B, the liquid sample S that has flowed into a low position in the second path 12B (for example, the position of a buffer path 121B described later) is pumped up to the height of the first path 11B, which is located in the positive direction of the Z axis from the low position.

[0061] The valve 43B allows the liquid sample S to pass at a flow rate corresponding to the degree of opening thereof, thereby supplying the liquid sample S at a predetermined flow rate to the first path 11B.

[0062] In the measurement device 10B according to the second embodiment, the pump 41B and the valve 43B are adjusted to maintain a constant height 56B of the surface 58B, and therefore the adjustment mechanism 4B can adjust the height 56B of the surface 58B of the liquid sample S flowing through the first path 11B to a constant height.

[0063] The pump 41B and the valve 43B are adjusted so that the focal point 50B between the X-ray tube 2 and the detector 3 is located on the surface 58B. More specifically, the pump 41B and the valve 43B are adjusted so that the intersection (focal point 50B) of the arrow 51B, which is the center line of the irradiation range 53B of the primary X-ray beam emitted from the X-ray tube 2, and the arrow 52B, which is the center line of the detection region 54B of the detector 3, is located on the surface 58B. With this configuration, primary X-rays can be irradiated onto the surface 58B, and fluorescent X-rays generated from the surface 58B can be detected. Therefore, fluorescent X-rays generated from light elements in the liquid sample S can also be detected with sufficient intensity without being attenuated within the liquid sample S. Therefore, the light elements in the liquid sample S can be analyzed with high sensitivity.

[0064] (4. Other Aspects of the Measurement Device) The specific configuration of the adjustment mechanism 4B is not particularly limited as long as it can maintain a constant position of the surface 58B of the liquid sample S flowing through the first path 11B. For example, an orifice configured to allow a predetermined amount of liquid to pass may be used instead of the valve 43B. Also, for example, the adjustment mechanism 4B' shown in FIG. 5 includes an outlet mechanism 44B that forms an outlet of the second path, instead of the valve 43B of the adjustment mechanism 4B of FIG. 4. The outlet mechanism 44B includes a tank 441B and a return pipe 442B. In the adjustment mechanism 4B' shown in FIG. 5, the liquid sample S pumped up by the pump 41B is stored in the tank 441B. The liquid sample S stored in the tank 441B then flows into the first path 11B through a tank opening 443B provided in the tank 441B. When the height of the liquid sample S stored in the tank 441B exceeds a predetermined value, the liquid sample S overflows and flows out from the return pipe 442B connected to the tank 441B. As a result, the height of the liquid sample S in the tank 441B can be maintained at a predetermined value. With the above configuration, the flow rate of the liquid sample S flowing through the first path 11B can be controlled. A static mechanism such as the outlet mechanism 44B has the advantage of being less prone to breakage than a dynamic mechanism such as a variable valve. On the other hand, a dynamic structure such as a variable valve has the advantage of being able to respond when the height of the liquid sample S needs to be changed for some reason.

[0065] In one embodiment, the first path 11B contains a predetermined amount of liquid sample S. In another embodiment, the amount of liquid sample S contained in the first path 11B is not predetermined and may vary for each measurement. Even when the amount of liquid sample S varies for each measurement, the adjustment mechanism 4B can maintain the height 56B of the surface 58B in the first path 11B at a predetermined position including the focal point 50B.

[0066] Preferably, a portion of the second path 12B includes a path that serves as a buffer for the liquid sample S flowing into the first path 11B. For example, in the example of Fig. 2, the portion between dashed lines 123B and 122B, which is the lowest portion of the second path 12B in the Z axis direction, is the buffer path 121B. The buffer path 121B can temporarily store excess liquid sample S in order to maintain the flow rate of the liquid sample S in the first path 11B at a predetermined value. Instead of the buffer path 121B, a tank that branches off from the second path 12B and can temporarily store excess liquid sample S may be provided.

[0067] Alternatively, the second path 12B may be provided horizontally. More specifically, the entire circulation path 1B may be provided on a horizontal plane. In this case, for example, excess liquid sample S may be stored in the buffer path 121B or in a tank replacing the buffer path 121B, and the flow rate of the first path 11B may be adjusted to a constant value by the pump 41B and the valve 43B.

[0068] Aspects It will be understood by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0069] (Item 1) An X-ray fluorescence analyzer according to one aspect includes an adjustment mechanism, an X-ray tube, a detector, and a control device. The first path has a first portion through which the liquid sample flows exposed. The adjustment mechanism adjusts the flow rate of the liquid sample flowing through the first path. The X-ray tube irradiates the liquid sample with primary X-rays in the first portion. The detector detects fluorescent X-rays generated from the liquid sample by the primary X-rays. The control device analyzes the fluorescent X-rays detected by the detector. The detector is positioned at a position where the fluorescent X-rays generated from the liquid sample directly enter. The adjustment mechanism adjusts the flow rate of the liquid sample so that the position of the surface of the liquid sample in the first portion remains constant.

[0070] According to the X-ray fluorescence analyzer described in the first aspect, an X-ray fluorescence analyzer that can easily perform light element analysis of a liquid sample with high sensitivity is provided.

[0071] (Item 2) The fluorescent X-ray analyzer according to item 1 further includes a second path that, together with the first path, forms a circulation path for the liquid sample.

[0072] According to the X-ray fluorescence analyzer described in paragraph 2, it is possible to repeatedly flow a liquid sample through the first path where X-ray fluorescence analysis is performed. Therefore, even a small amount of sample can detect fluorescent X-rays of sufficient intensity. Furthermore, circulating the liquid sample reduces the possibility of precipitation occurring in the liquid sample during measurement, which could affect the analysis.

[0073] (Item 3) In the fluorescent X-ray analyzer according to item 2, the first path is formed at a position where the liquid sample flows due to gravity.

[0074] According to the X-ray fluorescence analyzer described in the third aspect, the surface of the liquid sample falling through the first path can be irradiated with primary X-rays, and the fluorescent X-rays can be directly detected.

[0075] (4) In the first portion of the X-ray fluorescence analyzer described in (3), the entire periphery of the liquid sample is exposed.

[0076] If part of the first portion is covered with a pipe, a thin film, etc., there is a possibility that impurity rays may be generated from the pipe, thin film, etc., but the fluorescent X-ray analysis apparatus described in paragraph 4 can suppress the possibility of such impurity rays being generated.

[0077] (Item 5) The adjustment mechanism of the X-ray fluorescence analyzer according to item 3 or 4 includes an outlet mechanism or a pump that forms an outlet for the liquid sample from the second path to the first path.

[0078] According to the X-ray fluorescence analyzer described in item 5, the position of the surface in the first portion can be maintained at a predetermined position including the focal point by adjusting the state of the outlet mechanism or the pump.

[0079] (Item 6) In the first path of the fluorescent X-ray analyzer described in item 2, the liquid sample flows horizontally, and the top of the first path is open in the first section.

[0080] According to the X-ray fluorescence analysis apparatus described in paragraph 6, the surface of the liquid sample flowing horizontally through the first path can be irradiated with primary X-rays, and the fluorescent X-rays can be directly detected.

[0081] (Item 7) In the X-ray fluorescence analyzer according to item 6, the adjustment mechanism includes at least one of an outlet mechanism that forms an outlet of the second path, a pump, and a valve.

[0082] According to the X-ray fluorescence analysis apparatus described in paragraph 7, the position of the surface in the first portion can be maintained at a predetermined position including the focus by adjusting the state of at least one of the outlet mechanism, the pump, and the valve.

[0083] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0084] 1A, 1B Circulation path, 2 X-ray tube, 3 Detector, 4A, 4B Adjustment mechanism, 8A Pipe, 9 Control device, 10A, 10B Measuring device, 11A, 11B First path, 12A, 12B Second path, 41A, 41B Pump, 42A, 44B Outlet mechanism, 43B Valve, 50A, 50B Focus, 53A, 53B Irradiation range, 54A, 54B Detection area, 56B Height, 58A, 58B Surface of liquid sample (liquid level), 81B Gutter-shaped member, 90 Processor, 91 Memory, 92 Input device, 93 Output device, 110A, 110B First part, 111A, 111B First opening, 112A, 112B Second opening, 121A, 121B Buffer path, 122A Joint, 441B Tank, 442B return piping, 443B tank opening, 1000 analyzer, S liquid sample.

Claims

1. a first pathway having a first portion through which the liquid sample flows; an adjusting mechanism for adjusting the flow rate of the liquid sample flowing through the first path; an X-ray tube for irradiating the liquid sample with primary X-rays in the first portion; a detector for detecting fluorescent X-rays generated from the liquid sample by the primary X-rays; a control device for analyzing the fluorescent X-rays detected by the detector, the detector is disposed at a position where fluorescent X-rays generated from the liquid sample are directly incident thereon; the adjusting mechanism adjusts the flow rate of the liquid sample so that the position of the surface of the liquid sample in the first portion is kept constant; The X-ray fluorescence analysis apparatus further comprises a second path that, together with the first path, forms a circulation path for the liquid sample.

2. The X-ray fluorescence analysis apparatus according to claim 1 , wherein the first path is formed at a position where the liquid sample flows according to gravity.

3. 3. The X-ray fluorescence spectrometer according to claim 2, wherein the entire periphery of the liquid sample is exposed in the first portion.

4. 4. The X-ray fluorescence analyzer according to claim 2, wherein the adjustment mechanism includes an outlet mechanism or a pump that forms an outlet for the liquid sample from the second path to the first path.

5. In the first path, the liquid sample flows horizontally; The X-ray fluorescence analysis apparatus according to claim 1 , wherein an upper surface of the first path in the first portion is open.

6. The X-ray fluorescence analysis apparatus according to claim 5 , wherein the adjustment mechanism includes at least one of an outlet mechanism that forms an outlet of the second path, a pump, and a valve.