X-ray fluorescence analyzer and X-ray fluorescence analysis method

Abstract

The goal is to bring various types of samples as close as possible to the X-ray source and X-ray detector, while preventing them from colliding with the components of the X-ray fluorescence analyzer. [Solution] The X-ray fluorescence analyzer includes a height reference unit 6 that serves as a height reference for a sample S placed on a sample stage 4, a height position information acquisition unit 7 that acquires height position information indicating the height position of the height reference unit 6, and a sample stage control unit 8 that controls the position of the sample stage 4 based on the height position information acquired by the height position information acquisition unit 7.

Description

Technical Field

[0001] The present invention relates to a fluorescent X-ray analyzer and a fluorescent X-ray analysis method.

Background Art

[0002] A fluorescent X-ray analyzer is a device that irradiates a sample with X-rays from an X-ray source and detects fluorescent X-rays generated from the sample by an X-ray detector to perform qualitative or quantitative analysis of the sample.

[0003] In this type of fluorescent X-ray analyzer, in order to improve the analysis accuracy of fluorescent X-ray analysis, it is necessary to bring the sample as close as possible to the X-ray source and the X-ray detector. However, if the sample is brought too close to the X-ray source and the X-ray detector, there is a possibility that the sample may accidentally collide with the X-ray source or the X-ray detector.

[0004] Therefore, in a conventional fluorescent X-ray analyzer, as shown in Patent Document 1 for example, a height measurement mechanism measures the maximum height of a sample by irradiating the sample placed on a sample stage with laser light, and controls the movement of the sample stage based on the measured maximum height of the sample to adjust the position of the sample with respect to the X-ray source and the X-ray detector. Therefore, in a conventional fluorescent X-ray analyzer, by actually measuring the height of the sample by irradiating the sample with light, the sample is brought as close as possible to the X-ray source and the X-ray detector, and collisions between the sample and the X-ray source and the X-ray detector are prevented.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, when measuring the height of a sample by irradiating it with light on a sample stage, as in the X-ray fluorescence analyzer described above, it can be difficult to measure the height of the sample depending on the type of sample. Specifically, for example, if the sample surface is mirror-like, the sample itself is translucent, or the sample is extremely thin, such as a strand of hair, it is difficult to measure the height of the sample based on the light emitted from the sample. Therefore, with conventional X-ray fluorescence analyzers, it has been difficult to adjust the position of the sample relative to the X-ray source and X-ray detector for various types of samples.

[0007] Therefore, the present invention has been made in view of the above problems, and its main objective is to bring various types of samples as close as possible to the X-ray source and X-ray detector, and to prevent various types of samples from colliding with the components constituting the X-ray fluorescence analyzer. [Means for solving the problem]

[0008] In other words, the fluorescent X-ray analyzer of the present invention is characterized by comprising: an X-ray source that irradiates a sample with X-rays from above the sample; an X-ray detector that detects fluorescent X-rays generated from the sample from above the sample; a sample stage located below the X-ray source and the X-ray detector, on which the sample is placed and configured to be movable relative to the X-ray source and the X-ray detector; a height reference unit that serves as a height reference for the sample placed on the sample stage; a height position information acquisition unit that acquires height position information indicating the height position of the height reference unit; and a sample stage control unit that controls the position of the sample stage based on the height position information acquired by the height position information acquisition unit.

[0009] With this X-ray fluorescence analyzer, the sample stage control unit controls the position of the sample stage based on the height position information of the height reference unit, so the position of the sample relative to the X-ray source and X-ray detector can be adjusted without actually measuring the height of the sample. Therefore, various types of samples can be brought as close as possible to the X-ray source and X-ray detector, and various types of samples can be prevented from colliding with the components of the X-ray fluorescence analyzer.

[0010] The height position of the height reference section is one that coincides with the height position of the sample placed on the sample stand. With this configuration, the sample stage control unit can indirectly control the height of the sample by controlling the position of the sample stage based on the height position information of the height reference unit, thereby enabling high-precision adjustment of the sample's position relative to the X-ray source and X-ray detector.

[0011] The height position information acquisition unit includes a light irradiation unit that is provided at a predetermined height position and irradiates light, and a light detection unit that detects the light at the height position irradiated by the light irradiation unit. With this configuration, the height position information acquisition unit can acquire height position information optically.

[0012] An example of a housing that supports the X-ray source and the X-ray detector and houses the sample stage, and further comprises a housing with a window formed in its wall surface through which the X-rays and fluorescent X-rays pass, wherein the sample stage control unit controls the position of the sample stage so that the sample does not collide with the window. With this configuration, the sample stage control unit controls the position of the sample stage to prevent the sample from colliding with the window, thus preventing the sample from hitting the window.

[0013] An entrance is formed in the wall surface of the housing through which the sample is loaded onto the sample stage. The sample stage control unit controls the position of the sample stage from the loading position, which is the position of the sample stage when the sample is loaded onto the sample stage, to the measurement position, which is the position of the sample stage so that the sample does not collide with the window and the sample can be measured. The light irradiation unit and the light detection unit are provided on the path of the sample stage from the loading position to the measurement position. With this configuration, the light irradiation unit and the light detection unit are located on the path of the sample stage from the loading position to the measurement position, so the sample stage control unit can control the position of the sample stage based on height position information to prevent the sample from colliding with both the loading entrance and the window.

[0014] The height positions of the light irradiation unit and the light detection unit coincide with the height position of the height reference unit when the height position of the sample stage is at the height position of the measurement position. The sample stage control unit stops the raising of the sample stage based on the light detected by the light detection unit when the height reference unit is located in the optical path of the light from the light irradiation unit, and slides the sample stage toward the measurement position. With this configuration, the height of the sample stage when the height reference unit is positioned in the optical path of the light from the light irradiation unit will be the same as the height of the measurement position. Therefore, after the height position information acquisition unit acquires the height position information, the sample stage control unit only needs to slide the sample stage toward the measurement position, and there is no need to adjust the height of the sample stage when the sample stage is positioned below the window.

[0015] The height position information acquisition unit further includes a height position storage unit that stores the height position of the height reference unit when the height position information is acquired, and a distance estimation unit that estimates the distance between the X-ray source and the X-ray detector and the height reference unit based on the height position stored by the height position storage unit, and the sample stage control unit controls the position of the sample stage based on the distance estimated by the distance estimation unit. With this configuration, the sample stage control unit controls the position of the sample stage based on the distance estimated by the distance estimation unit, so the position of the sample can be optimally adjusted relative to the X-ray source and X-ray detector, regardless of the positional relationship between the height reference unit and the measurement position.

[0016] The aforementioned height reference section may be made of a light-shielding material. In this configuration, when the height reference unit is positioned in the optical path of the light emitted from the light irradiation unit, the height reference unit will block the light from the light irradiation unit. Therefore, the height position information acquisition unit can accurately acquire the height position information of the height reference unit based on the light detected by the light detection unit.

[0017] As a specific aspect of the height reference portion, it has a placement surface on which the sample is placed, further has a sample holder for holding the sample, and the height reference portion stands upward from the placement surface and is provided on the placement surface. With this configuration, the height position of the sample and the height position of the height reference portion can be compared with the placement surface as a reference, so that the height position of the sample can be adjusted with high accuracy based on the height position information of the height reference portion.

[0018] The sample is arranged between at least two of the height reference portions on the sample stage, is placed on the tops of at least two of the height reference portions, and further includes a lid portion that covers the sample. With this configuration, since the sample is arranged between at least two height reference portions, when the lid portion is placed on the tops of at least two height reference portions, it is possible to check whether there is a deviation between the height of the sample arranged on the sample stage and the height of the height reference portion. Specifically, when the lid portion wobbles when placed on the tops of two height reference portions, it can be seen that the height of the sample arranged on the sample stage is higher than the height of the height reference portion. On the other hand, when the lid portion is stably placed on the tops of two height reference portions, it can be seen that the height of the sample is below the height of the height reference portion.

[0019] It further includes a spacer portion interposed between the sample stage and the sample to enable adjustment of the height position of the sample. With this configuration, by arranging the sample on the sample stage via the spacer portion, the height position of the sample can be adjusted with respect to the height position of the height reference portion.

[0020] A plurality of the height reference portions are provided on the sample stage and have different heights from each other. With this configuration, even for samples with different heights, the position of the sample with respect to the X-ray source and the X-ray detector can be adjusted.

[0021] Examples of the height of the height reference portion being configured to be adjustable according to the height of the sample placed on the sample stage can be cited. With this configuration, since the height of the height reference portion can be adjusted, the working time for adjusting the height of the height reference portion to match the height of the sample can be shortened.

[0022] A fluorescence X-ray analysis method includes an X-ray source that irradiates an X-ray on a sample from above the sample, an X-ray detector that detects fluorescence X-rays generated from the sample from above the sample, and a sample stage that is located below the X-ray source and the X-ray detector and on which the sample is placed and is configured to be movable with respect to the X-ray source and the X-ray detector. The method includes obtaining height position information indicating the height position of a height reference portion that serves as a reference for the height with respect to the sample placed on the sample stage, controlling the position of the sample stage based on the obtained height position information, irradiating the sample with an X-ray from above the sample, and detecting fluorescence X-rays generated from the sample from above the sample.

[0023] Examples of the fluorescence X-ray analysis method include making the height position of the height reference portion coincide with the height position of the sample placed on the sample stage, and then obtaining height position information indicating the height position of the height reference portion that serves as a reference for the height with respect to the sample placed on the sample stage, controlling the position of the sample stage based on the obtained height position information, irradiating the sample with an X-ray from above the sample, and detecting fluorescence X-rays generated from the sample from above the sample. With such a configuration, the same operational effects as those of the above fluorescence X-ray analyzer can be obtained.

Effects of the Invention

[0024] According to the present invention, various types of samples can be brought as close as possible to the X-ray source and the X-ray detector, and various types of samples can be prevented from colliding with the members constituting the fluorescence X-ray analyzer.

Brief Description of the Drawings

[0025] [Figure 1]A schematic diagram showing a fluorescence X-ray analyzer according to the first embodiment of the present invention. [Figure 2] A front view of Figure 1 in the same embodiment. [Figure 3] This is a flowchart showing the X-ray fluorescence analysis method in the same embodiment. [Figure 4] A schematic diagram of the X-ray fluorescence analyzer in the same embodiment when the sample stage is located at the loading position. [Figure 5] A schematic diagram of an X-ray fluorescence analyzer in the same embodiment, where the height reference section is located on the optical path of light from the light irradiation section. [Figure 6] A schematic diagram of the X-ray fluorescence analyzer in the same embodiment when the sample stage is located at the measurement position. [Figure 7] A schematic diagram showing a fluorescence X-ray analyzer according to a second embodiment of the present invention. [Figure 8] A schematic diagram of the X-ray fluorescence analyzer in the same embodiment when the sample stage is located at the loading position. [Figure 9] A schematic diagram of an X-ray fluorescence analyzer in the same embodiment, where the height reference section is located on the optical path of light from the light irradiation section. [Figure 10] A schematic diagram of an X-ray fluorescence analyzer in which the sample stage is located below the window in the same embodiment. [Figure 11] A schematic diagram of the X-ray fluorescence analyzer in the same embodiment when the sample stage is located at the measurement position. [Figure 12] These are schematic diagrams showing the lid in other embodiments, (a) a schematic diagram showing the state of the lid when the height of the sample is less than or equal to the height of the height reference section, and (b) a schematic diagram showing the state of the lid when the height of the sample is greater than the height of the height reference section. [Figure 13] A schematic diagram showing the spacer portion in another embodiment. [Modes for carrying out the invention]

[0026] <First Embodiment> The fluorescent X-ray analyzer according to the first embodiment of the present invention will be described below with reference to the drawings. Note that, for the sake of clarity, some figures in the following diagrams may be simplified or exaggerated for illustrative purposes. The same reference numerals are used for identical components, and their descriptions are omitted as appropriate.

[0027] <Device configuration> The X-ray fluorescence analyzer 100 of this embodiment performs qualitative or quantitative analysis of elements contained in a sample S by irradiating it with X-rays from above and detecting the fluorescent X-rays generated above the sample S. It is a so-called top-irradiation type X-ray fluorescence analyzer. The type of sample S is not particularly limited; for example, the sample surface may be mirror-like, transparent, or extremely thin, such as a strand of hair.

[0028] Specifically, as shown in Figures 1 and 2, the X-ray fluorescence analyzer 100 comprises an X-ray source 2 that irradiates the sample S with X-rays from above, an X-ray detector 3 that detects fluorescent X-rays generated from the sample S from above, a sample stage 4 on which the sample S is placed and which is configured to be movable toward the X-ray source 2 and the X-ray detector 3, and a housing 5 that supports the X-ray source 2 and the X-ray detector 3 and houses the sample stage 4. The configuration of each part will be described below.

[0029] X-ray source 2 is, for example, an X-ray tube (not shown), which focuses the X-rays it generates using, for example, a collimator, and irradiates the sample S with X-rays. When X-ray source 2 irradiates sample S with X-rays, sample S is positioned below X-ray source 2.

[0030] The X-ray detector 3 detects fluorescent X-rays emitted upward from the sample S and converts them into a signal corresponding to their energy. When the X-ray detector 3 detects fluorescent X-rays from the sample S, the sample S is positioned below the X-ray detector 3.

[0031] The X-ray detector 3 outputs a signal corresponding to the energy of the fluorescent X-rays of the sample S to an information processing device (not shown). The information processing device is a general-purpose or dedicated computer equipped with a CPU, memory, input / output interface, etc., and performs at least the function of an analytical unit for analyzing the sample S by coordinating the CPU and peripheral devices according to a predetermined program stored in a predetermined area of ​​the memory.

[0032] The sample stage 4 is located below the X-ray source 2 and the X-ray detector 3, and the sample S is placed on it. Specifically, as shown in Figures 1 and 2, the sample stage 4 is, for example, flat, and the sample S is placed on the upper surface of the sample stage 4 facing the X-ray source 2 and the X-ray detector 3. Note that the shape of the sample stage 4 is not limited to a flat shape.

[0033] In this embodiment, the sample stage 4 is configured to be movable toward the X-ray source 2 and the X-ray detector 3. Specifically, as shown in Figure 1 in particular, the sample stage 4 is configured to be movable in at least two directions, vertical and horizontal, by means of a lifting actuator 4a that moves the sample stage 4 up and down and a horizontal actuator 4b that moves the sample stage 4 horizontally. In this embodiment, the lifting actuator 4a slides the sample stage 4 vertically, and the horizontal actuator 4b slides the sample stage 4 horizontally.

[0034] The housing 5 is roughly rectangular in shape, with a space formed inside for housing the sample stage 4. Here, as shown in Figures 1 and 2, the X-ray source 2 and the X-ray detector 3 are located on the outside of the housing 5.

[0035] As shown in Figure 1, an entrance 5a is formed on the wall of the housing 5 for loading the sample S onto the sample stage 4. The entrance 5a is an opening that allows the sample S to be loaded into and out of the sample stage 4 by opening and closing a door (not shown). Below the wall where the entrance 5a is formed, the loading position P1 is set, which is the position of the sample stage 4 when the sample S is loaded onto the sample stage 4. As shown in Figure 1, the entrance 5a is formed on the side wall of the housing 5 here, but the entrance 5a may also be formed on the top wall of the housing 5.

[0036] Furthermore, as shown in Figures 1 and 2, a window portion 5b is formed in the upper wall of the housing 5 through which X-rays and fluorescent X-rays pass. Specifically, the upper wall of the housing 5 faces the X-ray source 2 and the X-ray detector 3, and the window portion 5b is a film attached to a retaining frame having an opening formed in its upper wall. The window portion 5b is located at a different position from the entrance 5a in the horizontal direction.

[0037] As shown in Figures 1 and 2, the window portion 5b and the retaining frame that holds the window portion 5b are located inside the housing 5, relative to the X-ray source 2 and the X-ray detector 3. In this embodiment, the window portion 5b and the retaining frame that holds the window portion 5b are located on the innermost part of the upper wall of the housing 5. The X-ray source 2 is provided above the window portion 5b, with its X-ray emission port facing the window portion 5b. The X-ray detector 3 is also provided above the window portion 5b, with its fluorescent X-ray detection port facing the window portion 5b.

[0038] As shown in Figures 1 and 2, the X-ray fluorescence analyzer 100 of this embodiment further comprises a height reference unit 6 that serves as a height reference for a sample S placed on a sample stage 4, a height position information acquisition unit 7 that acquires height position information indicating the height position of the height reference unit 6, and a sample stage control unit 8 that controls the position of the sample stage 4 based on the height position information acquired by the height position information acquisition unit 7.

[0039] The height reference section 6 is columnar in shape with its top located above the sample stage 4. As shown in Figures 1 and 2, it has a mounting surface 9a on which the sample S is placed, and a sample holder 9 that holds the sample S is placed on the upper surface of the sample stage 4. The height reference section 6 is positioned on the mounting surface 9a, rising upward from it. In this embodiment, the height reference section 6 is a separate component from the sample S. In this embodiment, the height reference section 6 is integrated with the sample holder 9, but it may be a separate component.

[0040] Specifically, as shown in Figure 2, the height reference sections 6 are provided on one side and the other side of the mounting surface 9a, facing each other, and when the sample S is placed on the mounting surface 9a, the sample S is positioned between the two height reference sections 6. In this embodiment, the two height reference sections 6 have the same height from the mounting surface 9a to the top, but they may have different heights. Also, there may be only one height reference section 6 on the mounting surface 9a, or there may be three or more.

[0041] In this embodiment, as shown in Figures 1 and 2, the height from the mounting surface 9a to the top of the height reference section 6 is approximately the same as the height from the mounting surface 9a to the top of the sample S. As a result, the height position of the height reference section 6 coincides with the height position of the sample S placed on the mounting surface 9a. Here, the height position of the height reference section 6 refers to the position of the top of the height reference section 6 within the housing 5. More specifically, the height position of the height reference section 6 refers to the position of the top of the height reference section 6 relative to a predetermined reference position, such as the bottom surface of the housing 5. Furthermore, the agreement of height positions as referred to here includes not only the case where the height position of the height reference section 6 is equal to the height position of the sample S, but also the case where the height position of the height reference section 6 is slightly higher or lower than the height position of the sample S, within a range that does not affect the measurement of the sample S.

[0042] In this embodiment, the height reference section 6 is made of a light-shielding material, and the height position information acquisition section 7 optically acquires the height position information of the height reference section 6. In this embodiment, the height position information of the height reference section 6 is information indicating the height position of the top of the height reference section 6. Specifically, the height position information acquisition section 7 includes a light irradiation section 71 that is provided at a predetermined height position and irradiates light, and a light detection section 72 that detects the light at the height position irradiated by the light irradiation section 71.

[0043] The light irradiation unit 71 is, for example, a laser light source. In particular, as shown in Figure 2, the light irradiation unit 71 is provided inside the housing 5 on one side wall of the housing 5 and irradiates light horizontally toward the other side wall of the housing 5 opposite to the light irradiation unit 71. When the sample stage 4 is in the loading position P1, the optical path of the light from the light irradiation unit 71 is located directly above the height reference unit 6. The light irradiation unit 71 may also be a fiber connected to a light source such as a laser light source, in which case the light source may be provided outside the housing 5 and the fiber may be passed through the side wall of the housing 5 and connected to the light source.

[0044] The light detection unit 72 is a photodetector that detects light emitted from the light irradiation unit 71. In particular, as shown in Figure 2, the light detection unit 72 is provided inside the housing 5, on the side wall of the other housing 5 facing the light irradiation unit 71. The light detection unit 72 may also be a fiber connected to a photodetector. In this case, the photodetector may be provided on the outside of the housing 5, and the fiber may be passed through the side wall of the housing 5 and connected to the light source.

[0045] In this embodiment, the light detection unit 72 outputs a signal corresponding to the amount of light emitted from the light irradiation unit 71 to the arithmetic control unit PC. The arithmetic control unit PC is a general-purpose or dedicated computer equipped with a CPU, memory, input / output interface, etc., and performs at least the function of a sample stage control unit 8 by coordinating the CPU and peripheral devices according to a predetermined program stored in a predetermined area of ​​the memory. Furthermore, the arithmetic control unit PC may be a different computer from the information processing device (not shown) equipped with the analysis unit, or it may be the same computer.

[0046] The sample stage control unit 8 controls the position of the sample stage 4 within the housing 5 by driving the lifting actuator 4a and / or the horizontal actuator 4b based on the height position information acquired by the height position information acquisition unit 7.

[0047] Specifically, the sample stage control unit 8 drives the lifting actuator 4a to raise the sample stage 4 on which the sample S is placed from the loading position P1. When the amount of light output from the light detection unit 72 falls below a predetermined amount, the sample stage control unit 8 determines that the top of the height reference unit 6 is positioned in the optical path of the light from the light irradiation unit 71. Then, the sample stage control unit 8 stops driving the lifting actuator 4a and stops the raising of the sample stage 4.

[0048] Subsequently, the sample stage control unit 8 drives the horizontal actuator 4b to slide the sample stage 4 horizontally. When the sample stage 4 is positioned below the window section 5b, the sample stage control unit 8 stops driving the horizontal actuator 4b, thereby stopping the horizontal movement of the sample stage 4.

[0049] In this embodiment, the position of the sample stage 4 when its horizontal movement stops is the measurement position P2, which is the position of the sample stage 4 where the sample S can be measured without colliding with the window 5b. Here, the measurement position P2 is above the loading position P1 in the vertical direction and is a different position from the loading position P1 in the horizontal direction. The sample stage 4 is configured to be movable between the loading position P1 and the measurement position P2. When the sample stage 4 is in the measurement position P2, the top of the sample S is as close as possible to the window 5b and does not collide with the window 5b or the holding frame that holds the window 5b. Furthermore, since the X-ray source 2 and the X-ray detector 3 are provided above the window 5b and the holding frame, the top of the sample S does not collide with the X-ray source 2 and the X-ray detector 3 either.

[0050] Here, the light irradiation unit 71 and the photodetection unit 72 are located on the path from the loading position P1 to the measurement position P2 of the sample stage 4. The height positions of the light irradiation unit 71 and the photodetection unit 72 coincide with the height position of the height reference unit 6 when the height position of the sample stage 4 is at the height position of the measurement position P2. The height positions of the light irradiation unit 71, the photodetection unit 72 and the measurement position P2 refer to the positions of the light irradiation unit 71, the photodetection unit 72 and the measurement position P2 within the housing 5, respectively, and more specifically, they refer to the positions of the light irradiation unit 71, the photodetection unit 72 and the measurement position P2 with respect to a predetermined reference position, such as the bottom surface of the housing 5.

[0051] <X-ray fluorescence analysis method> Next, with reference to Figures 3 to 6, a fluorescent X-ray analysis method using the control by the sample stage control unit 8 of the first embodiment will be described in detail.

[0052] (a) Delivery process (see Figure 4) First, the sample S is placed on the mounting surface 9a of the sample holder 9 between the two height reference sections (S1). With the sample S placed on the mounting surface 9a, the height from the mounting surface 9a to the top of the height reference section 6 is the same as the height from the mounting surface 9a to the top of the sample S.

[0053] Next, with the sample S placed on the mounting surface 9a, the sample holder 9 is brought into the housing 5 and placed on the sample stage 4 (S2). As shown in Figure 4, when the sample holder 9 is brought into the housing 5, the sample stage 4 stops at the loading position P1.

[0054] (b) Sample stage raising process (see Figures 4 and 5) The sample stage control unit 8 raises the sample stage 4 from the loading position P1 (S3). Specifically, the sample stage control unit 8 drives the lifting actuator 4a to move the sample stage 4 vertically. As the sample stage 4 rises, the sample holder 9 and the height reference unit 6 also rise together with the sample stage 4.

[0055] Here, as the sample stage 4 rises from the loading position P1, the light irradiation unit 71 irradiates light toward the light detection unit 72, and the light detection unit 72 detects the light from the light irradiation unit 71 and converts it into a signal corresponding to the amount of light and outputs it. Then, the sample stage control unit 8 determines whether the top of the height reference unit 6 is located in the optical path of the light from the light irradiation unit 71 based on the amount of light output from the light detection unit 72 (S4).

[0056] Specifically, if the amount of light output from the light detection unit 72 is greater than a predetermined value, the sample stage control unit 8 determines that the top of the height reference unit 6 is located below the optical path of the light from the light irradiation unit 71, and raises the sample stage 4.

[0057] On the other hand, if the amount of light output from the light detection unit 72 is less than or equal to a predetermined value, the sample stage control unit 8 determines that the top of the height reference unit 6 is located in the optical path of the light from the light irradiation unit 71. The sample stage control unit 8 then stops driving the lifting actuator 4a and stops the sample stage 4 at the same height as the height of the measurement position P2 (S5). When the top of the height reference unit 6 is located in the optical path of the light from the light irradiation unit 71, the height of the sample stage 4 coincides with the height of the measurement position P2.

[0058] (c) Sample stage sliding process (see Figure 5) When the height of the sample stage 4 coincides with the height of the measurement position P2, the sample stage control unit 8 drives the horizontal actuator 4b to slide the sample stage 4 toward the measurement position P2 (S6). During this sliding motion, the height of the sample stage 4 does not change; specifically, it coincides with the height of the measurement position P2. In addition, the sample holder 9 and the height reference unit 6 slide along with the sample stage 4. The horizontal distance from the position where the sample stage 4 stops rising to the measurement position P2 is predetermined, and the sample stage control unit 8 moves the sample stage 4 horizontally based on this predetermined horizontal distance.

[0059] (d) Operation shutdown process (see Figure 6) When the sample stage 4 is positioned at the measurement position P2, the sample stage control unit 8 stops driving the horizontal actuator 4b, thereby stopping the horizontal movement of the sample stage 4 (S7). As shown in Figure 6, when the sample stage 4 is stopped at the measurement position P2, the top of the height reference section 6 and the top of the sample S are as close as possible to the window section 5b, and do not collide with the window section 5b or the holding frame that holds the window section 5b. Furthermore, since the X-ray source 2 and the X-ray detector 3 are located above the window section 5b and the holding frame, the top of the sample S does not collide with the X-ray source 2 or the X-ray detector 3 either.

[0060] (e) Measurement process (see Figure 6) With the sample stage 4 positioned at measurement position P2, X-ray fluorescence analysis of the sample S is performed. Specifically, as shown in Figure 6, the X-ray source 2 irradiates the sample S with X-rays from above through the window 5b, and the fluorescent X-rays generated upward from the sample S are detected by the X-ray detector 3 through the window 5b.

[0061] <Effects of the First Embodiment> In the X-ray fluorescence analyzer 100 of this embodiment, the sample stage control unit 8 controls the position of the sample stage 4 based on the height position information of the height reference unit 6. Therefore, the position of the sample S relative to the X-ray source 2 and X-ray detector 3 can be adjusted without actually measuring the height of the sample S. Consequently, various types of samples S can be brought as close as possible to the X-ray source 2 and X-ray detector 3, while preventing various types of samples S from colliding with the X-ray source 2 and X-ray detector 3.

[0062] <Second Embodiment> Hereinafter, a fluorescence X-ray analyzer according to a second embodiment of the present invention will be described with reference to the drawings. In the following, parts that differ from the first embodiment will be described, and the same components will be denoted by the same reference numerals and their descriptions will be omitted as appropriate.

[0063] Unlike the first embodiment (in which the height positions of the light irradiation unit 71 and the photodetector 72 coincide with the height position of the height reference unit 6 when the height position of the sample stage 4 is at the height position of measurement position P2), the X-ray fluorescence analyzer 100 in the second embodiment has a configuration in which the height positions of the light irradiation unit 71 and the photodetector 72 do not coincide with the height position of the height reference unit 6 when the height position of the sample stage 4 is at the height position of measurement position P2, as shown in Figure 7.

[0064] Specifically, the X-ray fluorescence analyzer 100 in the second embodiment further includes a height position storage unit 81 that stores the height position of the height reference unit 6 when the height position information acquisition unit 7 acquires height position information, and a distance estimation unit 82 that estimates the distance between the X-ray source 2 and the X-ray detector 3 and the height reference unit 6 based on the height position stored in the height position storage unit 81. In the second embodiment, the sample stage control unit 8 controls the position of the sample stage 4 based on the distance estimated by the distance estimation unit 82.

[0065] The height position storage unit 81 stores the height position of the height reference unit 6 when the top of the height reference unit 6 is located in the optical path of the light emitted from the light irradiation unit 71. Specifically, as in the first embodiment, when the amount of light output by the light detection unit 72 falls below a predetermined value, and the top of the height reference unit 6 is located in the optical path of the light emitted from the light irradiation unit 71, the height position storage unit 81 stores the height position of the height reference unit 6.

[0066] The distance estimation unit 82 estimates the distance between the window section 5b and the top of the height reference section 6 when the sample stage 4 is positioned below the window section 5b. Specifically, the distance estimation unit 82 obtains the height position stored by the height position storage unit 81 and the height position of the window section 5b, and estimates the distance based on the difference between these height positions.

[0067] Next, with reference to Figures 8 to 11, a detailed explanation will be given of the fluorescent X-ray analysis method using the control by the sample stage control unit 8 of the second embodiment.

[0068] (a) Delivery process (see Figure 8) First, as in the first embodiment, the sample S is placed on the mounting surface 9a of the sample holder 9 between the two height reference sections 6. With the sample S placed on the mounting surface 9a, the height from the mounting surface 9a to the top of the height reference section 6 is the same as the height from the mounting surface 9a to the top of the sample S.

[0069] Next, with the sample S placed on the mounting surface 9a, the sample holder 9 is brought into the housing 5 and placed on the sample stage 4. As shown in Figure 8, when the sample holder 9 is brought into the housing 5, the sample stage 4 stops at the loading position P1.

[0070] (b) Sample stage raising process (see Figures 8 and 9) The sample stage control unit 8 raises the sample stage 4 from the loading position P1. Specifically, the sample stage control unit 8 drives the lifting actuator 4a to raise the sample stage 4 vertically. As the sample stage 4 rises, the sample holder 9 and the height reference unit 6 also rise together with the sample stage 4. Here, the height position memory unit 81 may store the position of the height reference unit 6 on the sample stage 4 before raising the sample stage 4 from the loading position P1, or it may acquire the position of the height reference unit 6 on the sample stage 4 when raising the sample stage 4 from the loading position P1. Then, based on the position of the height reference unit 6 on the sample stage 4, the sample stage control unit 8 controls the position of the sample stage 4 so that the height reference unit 6 is positioned directly below the optical path of the light from the light irradiation unit 71.

[0071] Here, as the sample stage 4 rises from the loading position P1, the light irradiation unit 71 irradiates light toward the light detection unit 72, and the light detection unit 72 detects the light from the light irradiation unit 71, converts it into a signal corresponding to the amount of light, and outputs it.

[0072] Then, if the amount of light output from the light detection unit 72 is less than or equal to a predetermined value, the height position storage unit 81 stores the height position of the height reference unit 6 when the top of the height reference unit 6 is located in the optical path of the light from the light irradiation unit 71. Also, the sample stage control unit 8 stops the driving of the lifting actuator 4a and stops the upward movement of the sample stage 4. Here, as shown in Figure 9, when the top of the height reference unit 6 is located in the optical path of the light from the light irradiation unit 71, the height position of the sample stage 4 does not coincide with the height position of the measurement position P2.

[0073] (c) Sample stage sliding process (see Figure 9) When the lifting actuator 4a stops moving, the sample stage control unit 8 drives the horizontal actuator 4b to slide the sample stage 4 downwards toward the window section 5b. While the sample stage 4 is sliding, its height position does not change.

[0074] (d) Distance adjustment process (see Figure 10) When the sample stage 4 is positioned below the window section 5b, the sample stage control unit 8 stops driving the horizontal actuator 4b, thereby stopping the horizontal movement of the sample stage 4.

[0075] Then, the sample stage control unit 8 drives the lifting actuator 4a to raise the sample stage 4. While the sample stage 4 is rising, the distance estimation unit 82 estimates the distance between the window section 5b and the top of the height reference section 6, and the sample stage control unit 8 controls the position of the sample stage 4 based on the estimated distance.

[0076] Specifically, the sample stage control unit 8 compares the distance estimated by the distance estimation unit 82 with a predetermined distance. As shown in Figure 11, when the estimated distance reaches the predetermined distance, the lifting actuator 4a is stopped, and the raising of the sample stage 4 is stopped. The predetermined distance here is the distance at which the top of the height reference unit 6 and the window unit 5b are as close as possible and do not collide with each other. When the distance between the top of the height reference unit 6 and the window unit 5b reaches the predetermined distance, the sample stage 4 is located at the measurement position P2. The measurement process is the same as in the first embodiment, so its explanation is omitted.

[0077] <Effects of the second embodiment> In the X-ray fluorescence analyzer 100 of the second embodiment, the distance estimation unit 82 estimates the distance between the X-ray source 2 and the X-ray detector 3 and the height reference unit 6. Therefore, the position of the sample S can be optimally adjusted relative to the X-ray source 2 and the X-ray detector 3, regardless of the positional relationship between the height reference unit 6 and the measurement position P2.

[0078] <Other Embodiments> However, the present invention is not limited to the embodiments described above.

[0079] In the above embodiment, in order to determine whether the height position of the height reference section 6 coincides with the height position of the sample S placed on the mounting surface 9a, the fluorescent X-ray analyzer 100 may further include a lid C that is placed on at least two height reference sections 6 and covers the sample S, as shown in Figure 12. Specifically, the lid C is flat and is placed on the tops of the two height reference sections 6, spanning across the two height reference sections 6.

[0080] As shown in Figure 12(a), when the height from the mounting surface 9a to the top of the sample S is the same as or lower than the height from the mounting surface 9a to the top of the height reference section 6, the lid C is stably placed on the tops of the two height reference sections 6.

[0081] On the other hand, as shown in Figure 12(b), if the height from the mounting surface 9a to the top of the sample S is higher than the height from the mounting surface 9a to the top of the height reference section 6, the lid C will tilt relative to the mounting surface 9a and become unstable.

[0082] In the above embodiment, if the height from the mounting surface 9a to the top of the sample S is lower than the height from the mounting surface 9a to the top of the height reference section 6, the X-ray fluorescence analyzer 100 may further include a spacer section B interposed between the sample stage 4 and the sample S, as shown in Figure 13, to adjust the height of the sample S, in order to make the heights match. Specifically, the spacer section B is in the shape of a flat plate. The spacer section B is placed on the mounting surface 9a, and the sample S is placed on the upper surface of the spacer section B. In this state, the user adjusts the thickness of the spacer section B to make the height from the mounting surface 9a to the top of the sample S match the height from the mounting surface 9a to the top of the height reference section 6.

[0083] Alternatively, the height of the height reference section 6 may be configured to be adjustable according to the height of the sample S placed on the sample stand 4, in order to match the height from the mounting surface 9a to the top of the sample S with the height from the mounting surface 9a to the top of the height reference section 6.

[0084] In the above embodiment, the height position information acquisition unit 7 acquired height position information indicating the height position of the top of the height reference unit 6. However, the height position information acquisition unit 7 may acquire the height position of any part from the mounting surface 9a to the top of the height reference unit 6.

[0085] In the above embodiment, the height position information acquisition unit 7 acquired height position information optically, but is not limited to this. For example, if a barcode and / or characters attached to the height reference unit 6 contain information indicating the height from the mounting surface 9a to the top of the height reference unit 6, the height position information acquisition unit 7 may acquire the height position information by acquiring the information contained in the barcode and / or characters, for example. In this case, the height position information acquisition unit 7 may be, for example, a barcode reader that reads barcodes, or an OCR that reads characters, etc.

[0086] In the above embodiment, the height reference section 6 was provided on the mounting surface 9a of the sample holder 9, but it may also be provided on the sample stage 4.

[0087] In the second embodiment described above, the height position storage unit 81 stores the height position of the height reference unit 6 when the top of the height reference unit 6 is located in the optical path of light from the light irradiation unit 71, but it is not limited to this. For example, the height position storage unit 81 may store the height of the sample based on an image captured by an imaging unit located above the sample, which captures the reflected light from the sample.

[0088] Specifically, the X-ray fluorescence analyzer 100 further comprises a laser beam irradiation unit that irradiates the sample with a predetermined width of laser light from diagonally above, and an imaging unit provided above the sample that images the reflected light from the sample. Here, when the height of the sample stage 4 changes while the laser beam irradiation unit is irradiating with a band-shaped laser beam, the reflected light from the sample changes. The imaging unit images the reflected light from the sample, and the height position storage unit 81 stores the images captured by the imaging unit for each height of the sample stage 4. As a result, the height position storage unit 81 can store the height of the sample, and the sample stage control unit 8 can optimally adjust the position of the sample S relative to the X-ray source 2 and the X-ray detector 3 based on the stored height. Note that the laser beam irradiation unit may irradiate the height reference unit 6 or the sample stage 4 in addition to the sample. In this case, the imaging unit may image the reflected light from the height reference unit 6 or the reflected light from the sample stage 4, and the height position storage unit 81 may store the height of the height reference unit 6 or the height of the sample stage 4.

[0089] In the above embodiment, the sample stage control unit 8 moved the sample stage 4 by driving an actuator, but it is not limited to this. For example, the sample stage control unit 8 may control the relative position of the sample stage 4 with respect to the light irradiation unit 71, the photodetector unit 72, the X-ray source 2 and / or the X-ray detector 3 while the position of the sample stage 4 is fixed. Specifically, while the position of the sample stage 4 is fixed, the sample stage control unit 8 may move the light irradiation unit 71 and / or the photodetector unit 72 so that the light irradiation unit 71 and / or the photodetector unit 72 are brought closer to the sample stage 4. Alternatively, while the position of the sample stage 4 is fixed, the sample stage control unit 8 may move the X-ray source 2 and / or the X-ray detector 3 so that the X-ray source 2 and / or the X-ray detector 3 are brought closer to the sample stage 4.

[0090] Furthermore, the present invention can be modified in various ways, as long as it does not contradict its spirit. [Explanation of symbols]

[0091] 100... X-ray fluorescence analyzer 2...X-ray source 3. X-ray detector 4 ···Sample stage 5 ··· cabinet 5a... Loading entrance 5b ···Window section 6 ···Height reference section 7. Height and position information acquisition unit 71 ···Light irradiation section 72 ···Light detection unit 8. Sample stage control unit 9 ···Sample holder P1 ···Delivery location P2...Measurement position

Claims

1. An X-ray source that irradiates the sample with X-rays from above, An X-ray detector that detects fluorescent X-rays generated from the sample from above the sample, A sample stage located below the X-ray source and the X-ray detector, on which the sample is placed and configured to be movable toward the X-ray source and the X-ray detector, A height reference section, which serves as a height reference for the sample placed on the sample stage, A height position information acquisition unit that acquires height position information indicating the height position of the height reference unit, A fluorescent X-ray analyzer comprising a sample stage control unit that controls the position of the sample stage based on the height position information acquired by the height position information acquisition unit.

2. The X-ray fluorescence analyzer according to claim 1, wherein the height position of the height reference section coincides with the height position of the sample placed on the sample stage.

3. The height position information acquisition unit, A light-emitting section is provided at a predetermined height position and emits light, The fluorescent X-ray analyzer according to claim 1 or 2, further comprising: a light detection unit that detects light at a height position where the light irradiation unit irradiates light.

4. The housing further comprises a housing that supports the X-ray source and the X-ray detector, houses the sample stage, and has a window formed in its wall surface through which the X-rays and fluorescent X-rays pass, The X-ray fluorescence analyzer according to claim 3, wherein the sample stage control unit controls the position of the sample stage so that the sample does not collide with the window.

5. An opening is formed in the wall of the housing for loading the sample onto the sample stage. The sample stage control unit controls the position of the sample stage from the loading position, which is the position of the sample stage when the sample is loaded onto the sample stage, to the measurement position, which is the position of the sample stage when the sample is loaded onto the sample stage, until the sample can be measured without colliding with the window. The X-ray fluorescence analyzer according to claim 4, wherein the light irradiation unit and the light detection unit are provided on the path of the sample stage from the loading position to the measurement position.

6. The height positions of the light irradiation unit and the light detection unit coincide with the height position of the height reference unit when the height position of the sample stage is at the height position of the measurement position. The X-ray fluorescence analyzer according to claim 5, wherein the sample stage control unit stops the raising of the sample stage based on the light detected by the light detection unit when the height reference unit is located in the optical path of the light from the light irradiation unit, and slides the sample stage toward the measurement position.

7. The height position storage unit stores the height position of the height reference unit when the height position information acquisition unit acquires the height position information, The system further comprises a distance estimation unit that estimates the distance between the X-ray source and the X-ray detector and the height reference unit based on the height position stored in the height position storage unit, The X-ray fluorescence analyzer according to any one of claims 1 to 6, wherein the sample stage control unit controls the position of the sample stage based on the distance estimated by the distance estimation unit.

8. The X-ray fluorescence analyzer according to any one of claims 3 to 7, wherein the height reference section is made of a light-shielding material.

9. The device further comprises a sample holder having a mounting surface on which the sample is placed and a sample holder for holding the sample, The X-ray fluorescence analyzer according to any one of claims 1 to 8, wherein the height reference section is erected above the aforementioned mounting surface and provided on the aforementioned mounting surface.

10. The sample is placed between at least two of the height reference sections on the sample stand. The X-ray fluorescence analyzer according to any one of claims 1 to 9, further comprising a lid portion that is placed on the tops of at least two of the height reference portions and covers the sample.

11. The fluorescent X-ray analyzer according to any one of claims 1 to 10, further comprising a spacer interposed between the sample stage and the sample, which allows the height position of the sample to be adjusted.

12. The X-ray fluorescence analyzer according to any one of claims 1 to 11, wherein the height reference sections are provided in a plurality on the sample stage and have different heights from each other.

13. The X-ray fluorescence analyzer according to any one of claims 1 to 12, wherein the height of the height reference section is configured to be adjustable according to the height of the sample placed on the sample stage.

14. A method for analyzing X-ray fluorescence, comprising: an X-ray source that irradiates a sample with X-rays from above; an X-ray detector that detects fluorescent X-rays generated from the sample from above; and a sample stage located below the X-ray source and the X-ray detector, on which the sample is placed and configured to be movable relative to the X-ray source and the X-ray detector, Height position information is obtained that indicates the height position of the height reference part which serves as the height reference for the sample placed on the sample stage. Based on the acquired height position information, the position of the sample stage is controlled. A method for X-ray fluorescence analysis, comprising irradiating the sample with X-rays from above and detecting the fluorescent X-rays generated from the sample from above.

15. The height position of the height reference section is made to match the height position of the sample placed on the sample stand. Subsequently, height position information is acquired that indicates the height position of the height reference section, which serves as the height reference for the sample placed on the sample stage. Based on the acquired height position information, the position of the sample stage is controlled. The fluorescent X-ray analysis method according to claim 14, comprising irradiating the sample with X-rays from above and detecting the fluorescent X-rays generated from the sample from above.

Images