JP3677766B2 - X-ray fluorescence analyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wavelength-dispersive scanning X-ray fluorescence analyzer that uses a plurality of divergent slits interchangeably.
[0002]
[Prior art]
Conventionally, in a wavelength dispersive scanning X-ray fluorescence analyzer, secondary X-rays generated from a sample are taken out by a divergent slit (solar slit) facing the sample surface at a predetermined take-off angle, and interlocking means such as a goniometer Thus, the wavelength of the secondary X-ray dispersed by the spectroscopic element is changed, and the spectroscopic element and the detection unit are rotated so that the split secondary X-ray enters the detection unit (light receiving slit and detector). Specifically, the spectroscopic element is rotated around an axis along the light receiving surface, and the detection unit is rotated along a circle having a predetermined radius around the axis by twice the rotation angle (for example, (See Patent Documents 1 and 2).
[0003]
[Patent Document 1]
JP 2000-105206 A (paragraph 0013)
[Patent Document 2]
JP 2000-249667 A (paragraph 0025)
[0004]
[Problems to be solved by the invention]
Here, when a plurality of divergent slits having different opening angles are exchanged and used (see paragraphs 0032 to 0034 of Patent Document 2), the take-out angle may be slightly changed by the exchange. The secondary X-ray to be analyzed is incident on the detection unit at a rotational position shifted from a predetermined rotational position by the interlocking unit, and is not sufficiently accurate. Since the interlocking means that always rotates the detection unit twice the spectroscopic element cannot correct this optical system shift, it has been changed so that the extraction angle does not change even if the diverging slit is replaced. For each divergent slit, the take-out angle is correct by adjusting the mounting position with respect to the exchange mechanism by trial and error so that the measurement intensity of the predetermined secondary X-ray at the predetermined rotational position by the interlocking means becomes the maximum. The angle was unified. This work took a long time even for skilled workers.
[0005]
The present invention has been made in view of the above-mentioned conventional problems. In a wavelength dispersion type scanning X-ray fluorescence analyzer, an optical system shift caused by exchanging a diverging slit is automatically detected on the spectroscopic element and the detection unit side. It is an object of the present invention to provide a device that can easily and sufficiently analyze accurately.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is first an X-ray fluorescence analyzer comprising the following X-ray source, divergence slit, spectroscopic element, detection unit, and interlocking means. The X-ray source irradiates the sample with primary X-rays. The divergence slit faces the sample surface at a predetermined take-off angle and allows secondary X-rays generated from the sample to pass through. The spectroscopic element splits secondary X-rays that have passed through the diverging slit. The detection unit includes a light receiving slit that allows the secondary X-rays dispersed by the spectroscopic element to pass through, and a detector that measures the intensity of the secondary X-ray that has passed through the light receiving slit. The interlocking unit changes the wavelength of the secondary X-rays dispersed by the spectroscopic element, and drives the spectroscopic element and the detection unit independently from each other so that the split secondary X-ray enters the detection unit. Rotate with
[0007]
Further, the present apparatus includes a plurality of the divergence slits, an exchange mechanism for exchanging the divergence slits, and an extraction angle correction unit. The take-out angle correcting means replaces the divergence slit as a reference by the exchange mechanism, operates the interlocking means so that secondary X-rays of a predetermined wavelength are incident on the detection unit, and the exchange mechanism Replace the diverging slit, rotate the spectroscopic element and the detection unit by the same angle in a predetermined angle range, and set the rotation angle at which the intensity of the secondary X-ray of the predetermined wavelength measured by the detection unit is maximized This is stored as a deviation of the take-off angle of the divergent slit, and when the interlocking mechanism is operated by exchanging with the other divergent slit by the exchange mechanism, the spectroscopic element including the memorized take-off angle deviation is detected. Rotate the part.
[0008]
According to the fluorescent X-ray analysis apparatus of the present invention, since the spectroscopic element and the detection unit are rotated by independent drive mechanisms, the deviation of the extraction angle with respect to the exchanged divergence slit by the operation of the extraction angle correction means described above. It is possible to rotate the spectroscopic element and the detection unit so as to detect and correct it. That is, the optical system shift due to the replacement of the diverging slit is automatically corrected on the spectroscopic element and the detection unit side, and a sufficiently accurate analysis can be easily performed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an apparatus according to an embodiment of the present invention will be described. First, the configuration of this apparatus will be described with reference to FIG. This apparatus is a wavelength-dispersion scanning X-ray fluorescence analyzer. First, the following X-ray source 3, divergent slit 5, spectroscopic element 8, detector 12, and interlocking means 15 are provided. Prepare. The X-ray source 3 is an X-ray tube or the like that irradiates the sample 1 with the primary X-ray 2. The diverging slit 5 faces the surface of the sample 1 (the lower surface in the figure) at a predetermined take-off angle φ and allows secondary X-rays 4 such as fluorescent X-rays generated from the sample 1 to pass through. The spectroscopic element 8 splits the secondary X-ray 6 that has passed through the diverging slit 5. The detection unit 12 includes a light receiving slit 10 that allows the secondary X-ray 9 dispersed by the spectroscopic element 8 to pass through, and a detector 11 that measures the intensity of the secondary X-ray that has passed through the light receiving slit 10. The divergence slit 5 and the light receiving slit 10 are so-called solar slits, that is, X-rays in a desired direction (longitudinal direction of the foil) in which a large number of foils perpendicular to the paper surface of the drawing are arranged in parallel at regular intervals to allow X-rays to pass therethrough. The open angle of the solar slit, that is, the open angle of the X-ray passing through the solar slit, is determined by the interval and the length of the foil constituting the solar slit.
[0010]
The interlocking unit 15 changes the wavelength of the secondary X-ray 9 dispersed by the spectroscopic element 8, and connects the spectroscopic element 8 and the detection unit 12 to each other so that the split secondary X-ray 9 enters the detection unit 12. It is rotated by independent drive mechanisms 13 and 14. For example, when the secondary X-ray 6A is incident on the spectroscopic element 8 at a certain incident angle θ, the secondary X-ray 6A that is split (diffracted) by the extension line 7 of the secondary X-ray 6A and the spectroscopic element 8 has an incident angle θ. The interlocking means 15 changes the wavelength of the secondary X-ray 6A that is split by changing the spectral angle 2θ, while the split secondary X-ray 9A is detected by the detector 12. So that the spectroscopic element 8 is rotated by the θ-axis drive mechanism 13 about an axis O perpendicular to the paper surface passing through the center of the surface thereof, and the detection unit 12 is moved about the axis O by twice the rotation angle. Is rotated by a 2θ-axis drive mechanism 14 along a circle 16. The θ-axis drive mechanism 13 and the 2θ-axis drive mechanism 14 are each composed of a pulse motor, a gear, and the like by known techniques, but are not mechanically connected to each other and are independent.
[0011]
Further, in this apparatus, the diverging slits 5A, 5B, and 5C are plural and the opening angles are different (the opening angles increase in the order of 5B, 5A, and 5C), and an exchange mechanism that replaces the diverging slits 5A, 5B, and 5C. 17 and a take-out angle correction means 18. The take-out angle correcting means 18 is exchanged with the divergence slit 5A which is a reference by the exchange mechanism 17, and the interlocking means 15 is operated so that the secondary X-ray 9A having a predetermined wavelength is incident on the detection unit 12. In order to maximize the intensity of the secondary X-ray 9B having a predetermined wavelength measured by the detector 12, the spectral element 8 and the detector 12 are rotated by the same angle in a predetermined angle range. When the rotation angle α is stored as a take-off angle shift (φB−φA) with respect to the other divergent slit 5B and analyzed using the other divergent slit 5B, that is, the other divergent slit by the exchange mechanism 17. When the interlocking means 15 is operated by replacing with 5B, the spectroscopic element 8 and the detection unit 12 are rotated including the stored take-off angle deviation α.
[0012]
Next, the operation of this apparatus will be described. First, the positional relationship (rotational angle relationship) between the spectroscopic element 8 and the detection unit 12 is appropriately set for the secondary X-ray 9A having a predetermined wavelength with reference to the divergent slit 5A (extraction angle φA) having a standard opening angle. Adjust to. The following operation is automatically performed by the take-out angle correction means 18. First, the switching mechanism 17 is replaced with a divergence slit 5A that is a reference (this operation is not necessary when the slit is already replaced), and interlocked so that secondary X-rays 9A having a predetermined wavelength are incident on the detection unit 12. The means 15 is activated. That is, the spectroscopic element 8 and the detection unit 12 are rotated to the predetermined position adjusted in advance by the θ-axis drive mechanism 13 and the 2θ-axis drive mechanism 14.
[0013]
Next, the exchange mechanism 17 is replaced with another diverging slit 5B having a smaller opening angle. The exchange angle may change from φA to φB, for example, due to this exchange, and when this happens, the secondary X-ray optical path of a predetermined wavelength and the light receiving surface of the spectroscopic element 8 are dotted lines from those indicated by the solid lines in the figure. It changes to the one shown in. Therefore, the spectroscopic element 8 and the detection unit 12 are rotated by the same angle in a predetermined angle range, for example, ± 1 degree, and the rotation angle α () at which the intensity of the secondary X-ray 9B having a predetermined wavelength measured by the detection unit 12 is maximized. (Which can be a negative value depending on the direction) is detected and stored as the deviation (φB−φA) of the take-off angle for the other diverging slit 5B.
[0014]
When analyzing using the other divergence slit 5B, that is, when exchanging the divergence slit 5B to the other divergence slit 5B by the exchange mechanism 17 and operating the interlocking means 15, the stored deviation of the take-out angle is determined. The spectroscopic element 8 and the detection unit 12 are rotated including α. In other words, assuming that the rotational positions of the spectroscopic element 8 and the detection unit 12 when analyzing the secondary X-ray of a certain wavelength using the reference divergence slit 5A are θ and 2θ, respectively, the other divergences. The rotational positions of the spectroscopic element 8 and the detection unit 12 when analyzing using the slit 5B are θ + α and 2θ + α, respectively.
[0015]
As described above, according to the X-ray fluorescence analysis apparatus of the present embodiment, the spectroscopic element 8 and the detection unit 12 are rotated by the drive mechanisms 13 and 14 independent of each other. It becomes possible to rotate the spectroscopic element 8 and the detection unit 12 so as to detect the deviation α of the take-out angle with respect to the exchanged diverging slit 5B and correct it. That is, the optical system shift caused by the replacement of the diverging slit 5 is automatically corrected on the spectroscopic element 8 and the detection unit 12 side, and a sufficiently accurate analysis can be easily performed.
[0016]
Although the divergence slit 5B having the smallest opening angle may be used as a reference, doing so makes it difficult to adjust the positions of the spectroscopic element 8 and the detection unit 12 in advance. The apparatus of this embodiment is a so-called bottom irradiation type that irradiates the sample 1 with the primary X-ray 2 from below, but the present invention is not limited to this, and may be a top irradiation type that irradiates from above.
[0017]
【The invention's effect】
As described above in detail, according to the present invention, since the spectroscopic element and the detection unit are rotated by independent drive mechanisms, the extraction angle of the exchanged divergence slit by the operation of the extraction angle correction unit described above. It is possible to rotate the spectroscopic element and the detection unit so as to detect the deviation and correct it. That is, the optical system shift due to the replacement of the diverging slit is automatically corrected on the spectroscopic element and the detection unit side, and a sufficiently accurate analysis can be easily performed.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an X-ray fluorescence analyzer according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Sample, 2 ... Primary X-ray, 3 ... X-ray source, 4 ... Secondary X-ray generated from sample, 5 ... Divergence slit, 5A ... Reference divergence slit, 5B ... Other divergence slits, 6 ... secondary X-rays that have passed through the diverging slit, 8 ... spectral element, 9 ... secondary X-rays dispersed by the spectroscopic element, 10 ... light receiving slit, 11 ... detector, 12 ... detection unit, 13, 14 ... independent of each other Drive mechanism, 15 ... interlocking means, 17 ... replacement mechanism, 18 ... take-out angle correction means, α ... take-off angle deviation, φ ... take-out angle.

Claims (1)

An X-ray source for irradiating the sample with primary X-rays;
A diverging slit that faces the sample surface at a predetermined take-off angle and allows secondary X-rays generated from the sample to pass through;
A spectroscopic element that splits secondary X-rays that have passed through the diverging slit;
A detector comprising a light receiving slit for passing secondary X-rays dispersed by the spectroscopic element and a detector for measuring the intensity of the secondary X-ray passed through the light receiving slit;
Interlocking of rotating the spectroscopic element and the detection unit with mutually independent drive mechanisms so that the wavelength of the secondary X-ray dispersed by the spectroscopic element is changed and the split secondary X-ray is incident on the detection unit A fluorescent X-ray analyzer comprising means,
A plurality of the diverging slits;
With an exchange mechanism that replaces the diverging slit,
The exchange mechanism is replaced with a divergence slit that is used as a reference, and the interlocking unit is operated so that a secondary X-ray having a predetermined wavelength is incident on the detection unit, and the exchange mechanism is replaced with another divergence slit. The spectroscopic element and the detection unit are rotated by the same angle in a predetermined angle range, and the rotation angle at which the intensity of the secondary X-ray of the predetermined wavelength measured by the detection unit is maximized is taken out for the other diverging slits. An extraction angle that is stored as an angular deviation and rotates the spectroscopic element and the detection unit including the stored deviation in the extraction angle when the exchange mechanism is replaced with the other divergent slit and the interlocking unit is operated. X-ray fluorescence analyzer equipped with correction means.

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