JPH0720069A - X-ray spectrometer - Google Patents

Abstract

PURPOSE:To provide an X-ray spectrometer which can be positioned around an X-ray generating point without affecting the size of a sample and the position of a sample supporting and moving mechanism and, at the same time, the spectroscope element of which can be moved within a wide extent. CONSTITUTION:In an X-ray spectrometer which separates light by means of a spectroscope element 4 moving along a straight shaft 6 passing through an origin O, a link groove 8 formed along the curve expressed by polar coordinates r=2Rsin2theta (where, R and theta respectively represent the radius of a Rowland circle and angle of the shaft 6) or part of the curve when the angle of the shaft is theta=0 and a link mechanism which controls the distances from the origin O to the element 4 and from the element 4 to a detector 5 on the groove 8 to the same distance are provided. The link mechanism is constituted in such a way that one end of its straight part having a length of 2Rsinpsi is set at the point of the element 4 and the other end is set at a point on a straight line drawn through the origin) at an angle of psi against the shaft 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray spectroscope, and more particularly to a linear condensing X-ray spectroscope which moves a spectroscopic element on a straight line passing through an X-ray generation point.

[0002]

2. Description of the Related Art An X-ray spectroscope is used in an apparatus such as an X-ray microanalyzer, in which X-rays emitted from an X-ray generation point on a sample are separated by a spectroscopic element and made incident on a detector. ing. A linear condensing X-ray spectrometer is known as this X-ray spectroscope. In this linear condensing X-ray spectroscope, the X-ray extraction direction from the X-ray generation point is always constant. In order to disperse the X-rays, the curved dispersive element is moved along a straight line, and at the same time, the dispersive element itself is rotated to change the incident angle of the X-rays incident on the dispersive element.

Conventionally, a configuration shown in FIG. 6 is known as a configuration for arranging a large number of spectroscopes around an X-ray generation point. In FIG. 6, the X-ray spectroscope is composed of constituent elements and a mechanism connecting the constituent elements, and the constituent elements are arranged along a first straight line (AA ') passing through the X-ray generation point. First moving axis and the second passing through the X-ray generation point
A second movement axis arranged along the straight line (AA), and a spectroscopic element arranged so that its lattice plane tangent is in contact with the Roland circle on a table moving on the first movement axis. Second
Third straight line (DD ′) intersecting the straight line (AA) of
And a third axis rotatably installed at an intersection (D) of the second straight line and the third straight line on a table arranged along the second axis and moving on the second axis. There is an X-ray detector provided on a sliding table, and as a mechanism, the central portion (B) of the spectroscopic element moving on the first axis, the intersection (D) of the second straight line and the third axis. A first mechanism for linking the movements of the movable table on the first movable axis and the movable table on the second movable axis in order to keep the length between the two) constant even by the movement of the spectroscopic element, The angle formed by the third axis and the second straight line is always the central portion (B) of the spectroscopic element even when the intersection (D) moves.
And a second mechanism for maintaining a relationship of twice the angle formed by the second straight line (AA) and the straight line connecting the intersection point (D) with X.
There is a third mechanism that always constrains the slit points of the line detector on the Roland circle.

The first mechanism and the second mechanism constitute a mechanism for keeping the distance between the sample and the spectroscopic element and the distance between the spectroscopic element and the detector on the Rowland circle equal. is doing.

[0005]

In the conventional X-ray spectroscope, (1) the distance between the sample and the spectroscopic element and the distance between the spectroscopic element and the detector are kept equal on the Rowland circle. And the mechanism for the detector to face the spectroscopic element are complicated.

(2) The mechanism of (1) above is large, and a large mechanism exists below the sample surface and near the analysis point. Therefore, the size of the sample and the mechanism for supporting and moving the sample are limited. There is a problem.

Therefore, the present invention solves the above-mentioned problems of the conventional X-ray spectroscope, and the structure for arranging the spectroscope around the X-ray generation point supports the sample size and the sample and moves. It is an object of the present invention to provide an X-ray spectroscope that can increase the movable range of the spectroscopic element without affecting the position where the mechanism is installed.

[0008]

In order to achieve the above object, the present invention provides an X-ray spectroscope that performs spectroscopic analysis by a spectroscopic element that moves on a linear axis passing through the origin, where R is the radius of a Rowland circle, and When the angle of the linear axis is θ = 0,
The first link mechanism whose locus is a curve represented by the polar coordinate r = 2Rsin2θ or a part thereof, and the distance from the origin to the spectroscopic element and the distance from the spectroscopic element to the detector on the first link mechanism are equal distances. A second link mechanism restrained to
The third link mechanism is formed by a straight line having a length of 2Rsin ψ, one end of which is a point of the spectroscopic element, and the other end is a point on a straight line that passes through the origin and forms an angle ψ with the straight line axis.

In the present invention, the first link mechanism is the second
Along with the link mechanism, the sample, the spectroscopic element and the detector are placed on the same Rowland circle, and the distance between the sample and the spectroscopic element and the distance between the spectroscopic element and the detector are held equal and The slit of the vessel is directed toward the spectroscopic element.

In the present invention, the straight line of length 2Rsinψ of the third link mechanism is a chord of an arc having a radius R and a central angle of 2ψ, and instead of the straight line of length 2Rsinψ, an arc of radius R and a central angle of 2ψ. Can also be The third link mechanism determines the angle so that the spectroscopic element is in contact with the Rowland circle.

In the present invention, the spectroscopic element is a collection of a dispersive crystal, a multilayer film, a diffraction grating and the like.

[0012]

With the above construction, in an X-ray spectrometer that performs spectroscopy with a spectroscopic element that moves on a linear axis passing through the origin, R is the radius of the Rowland circle, and the linear axis is θ =
When the angle is 0, the X-ray detector is arranged on the first link mechanism having the curve represented by the polar coordinate r = 2Rsin2θ or a part thereof as the locus, and the distance from the origin to the spectroscopic element and the spectroscopic element The second link mechanism that restricts the distance to the detector on the first link mechanism to an equal distance defines the positional relationship between the spectroscopic element and the detector, and the first link mechanism and the second link mechanism , The sample, the spectroscopic element and the detector are placed on the same Rowland circle, the distance between the sample and the spectroscopic element and the distance between the spectroscopic element and the detector are kept equal, and the slit of the detector is Aim at the dispersive element. Further, a length 2 in which one end is a point of the spectroscopic element, and a point on a straight line passing through the origin and forming an angle with the linear axis is ψ is the other end
By the third link mechanism composed of a straight line of Rsin ψ, the crystallographic plane of the spectroscopic element is in contact with the Roland circle, with the angle of attachment of the spectroscopic element being the angle between the direction of the crystal plane of the spectroscopic element and the straight line of length 2Rsin ψ. To decide.

As a result, in the linear condensing X-ray spectroscope, X-rays are dispersed with the extraction direction of the X-rays from the X-ray generation point always kept constant, and the curved spectroscopic element is arranged along the straight line. The incident angle of the X-ray incident on the spectroscopic element is changed by moving the spectroscopic element itself while moving the spectroscopic element.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings, but the present invention is not limited to the embodiments.

[Structure of Embodiment] In the X-ray spectrometer, X
In order to perform X-ray spectroscopy in a state where the X-ray extraction direction from the line generation point is always constant, the spectroscopic element is moved along a straight line and at the same time the spectroscopic element itself is rotated. A mechanism for changing the incident angle of X-rays incident on is required. Therefore, in the following, the principle of the mechanism of the X-ray spectroscope of the present invention is (a) to keep the distance between the sample and the spectroscopic element and the distance between the spectroscopic element and the detector equal on the Rowland circle. And a mechanism for allowing the slits of the detector to face the direction of the spectroscopic element (hereinafter referred to as mechanism a), and (b) a mechanism for determining the angle so that the spectroscopic element is in contact with the Roland circle (hereinafter referred to as mechanism). (b)), and then a more specific embodiment of the mechanism based on the principle will be described.

(Structure of Mechanism a) First, the principle of the mechanism a will be described with reference to FIG. 4 for explaining the principle of the mechanism of the X-ray spectrometer of the present invention.

In FIG. 4, when the sample 1 is placed at the origin of the x-axis and the electron beam 2 is incident from the y-axis direction, the sample 1 emits X-rays. The X-ray emitted from the sample 1 in the direction of the angle α with respect to the x-axis (the direction of the X-axis) is separated by the spectroscopic element 4 arranged on the X-axis and then detected by the detector 5. At this time, when the X-ray generation point on the sample 1 is point O (origin), the central position of the spectroscopic element 4 is point T, and the slit position of the detector 5 is point P in the figure, points O, T, and P is always located on the Roland circle, and points O and T
Between the points T and P and the distance TP between the points T and P are equal, and the spectroscopic element 4 is in contact with the Roland circle at the point T.
By directing the slit of the detector 5 in the direction of the point T, it is possible to configure a linear focusing X-ray spectrometer.

As a configuration for that purpose, the following configurations (A) and (B) are used in the embodiment of the present invention.

(A) A link mechanism having a locus of a curve represented by polar coordinates r = 2Rsin2θ or a part thereof, where R is the radius of a Rowland circle and the X axis is an angle of θ = 0.

(B) When the distance from the origin O is t and the moving point T moving on the X axis is one end point and the point P at the slit position of the detector 5 is the other end point, the moving point is T and point P
A link mechanism that constrains the distance t and the distance t from the origin of the moving point T to be equal, and the slit faces the direction of the spectroscopic element.

First, the link mechanism (A) will be described. In FIG. 4, assuming that the radius of the Rowland circle is R and the point at a distance R from each of the points O, T, and P is Q, the triangle OTQ and the triangle PTQ are congruent, and the angle TOP is θ. Angle TQ because it has an angle
The angle becomes 2θ together with O and the angle TQP. Therefore,
A point P on the Roland circle is a point on the curve represented by r = 2Rsin2θ. When the link mechanism is configured so that the detector 5 moves on the curve represented by this r = 2Rsin2θ, the detector 5 exists on the Roland circle. This link mechanism can be configured by a link groove having a curved locus represented by r = 2Rsin2θ, for example.

Next, the link mechanism (B) will be described. In FIG. 4, the distance between the OTs and the distance between the TPs are both set to t by the link mechanism, and the X-ray reaching the spectroscopic element on the point T moving on the Roland circle is
Point P moving on the Roland circle by the mechanism (A)
Will converge to. It should be noted that this link mechanism can be realized by a combination of, for example, a linear slide mechanism which has a point of the spectroscopic element as an end point and can rotate about the point as an axis, and a wire mechanism which expands and contracts according to the movement of the spectroscopic element.

Thus, once the slit direction of the detector 5 is set in the direction of the point T on the link mechanism having the curve represented by the polar coordinate r = 2Rsin2θ or a part thereof as the locus, the angle OPT is always the angle θ. Then, the slit of the detector 5 faces the direction of the spectroscopic element 4.

Therefore, the distance between the sample and the spectroscopic element and the distance between the spectroscopic element and the detector are held equal on the Rowland circle by the link mechanism of the mechanism (A) and the mechanism (B). Also, the slit of the detector is oriented towards the spectroscopic element.

(Structure of Mechanism b) Next, the principle of the mechanism b will be described with reference to FIG. 5 for explaining the principle of the mechanism of the X-ray spectrometer of the present invention.

In FIG. 5, the X-ray generation point on the sample 1 is the point O (origin), the emission direction of the X-ray emitted from the point O is the X-axis 6, the X-axis 6 is moved, and the central position of the spectroscopic element 4 is set. The moving point on the moving axis 9 is the point R, the straight line passing through the point O and the angle formed by the X axis is ψ, the moving point on the moving axis 9 is the point R, one end is the point T, and the other end is the point. As S, both points T and S have radius R and central angle 2
Move on the arc 10 of ψ. At this time, assuming that the center of the arc 10 is the point U, the triangle STU is an isosceles triangle in which the angle of the point U is 2ψ and the angles of the other two points T and S are (π−ψ). The tangent angle of the arc 10 is an angle ψ with respect to the straight line YS.

Therefore, by disposing the spectroscopic element 4 in contact with the circular arc 10 at this point T, the angle can be determined so that the spectroscopic element 4 is in contact with the Rowland circle.

As a structure for this purpose, the following structure (C) or (D) can be used in the embodiment of the present invention.

(C) A moving point T on the X axis passing through the point O and a moving point S on the moving axis 9 passing through the point O and forming an angle between the X axis and the X axis. A link mechanism in which T and point S are arcs having a radius R and end points of an arc having a central angle 2ψ.

(D) A moving point T on the X axis passing through the point O and a moving point S on the moving axis 9 passing through the point O and having an angle ψ with the X axis are defined as A link mechanism in which T and a point S are chords connecting a point T and a point S of an arc having a radius R and both ends of an arc having a central angle 2ψ.

In the above-mentioned link structure, the link structure (C) is a structure in which the arc 10 is formed by an arc of that shape, and one end of the arc is moved along a moving axis installed above the X axis. By making the other end movable along a moving axis installed on a straight line forming an angle ψ with the X axis, the angle of the spectroscopic element 4 moving on the X axis is determined so as to be in contact with the Roland circle. be able to.

Further, the link structure (D) is a structure in which the arc 10 is constituted by a string connecting both ends of the arc, and one end of the string is moved along a moving axis installed above the X axis. By making the other end movable along a moving axis installed on a straight line forming an angle ψ with the X axis,
The angle of the spectroscopic element 4 moving on the X axis can be determined so as to be in contact with the Rowland circle.

Therefore, by combining the configurations a and b, in the X-ray spectroscope, the spectroscopic element is moved along a straight line, and at the same time, the spectroscopic element itself is rotated to enter the spectroscopic element. The incident angle of the X-ray can be changed, and the X-ray can be detected by performing X-ray spectroscopy while keeping the X-ray extraction direction from the X-ray generation point always constant.

(One Example of Mechanism of X-ray Spectrometer) Next, one configuration diagram for explaining the mechanism of the X-ray spectrometer of the present invention in FIGS. 1 and 2, and the X-ray spectrometer of the present invention in FIG. This will be described with reference to the wire connection diagram. 2 shows the state on the back side of FIG.

First, an embodiment of the mechanism of the X-ray spectrometer will be described with reference to FIGS. In FIGS. 1 and 2, the sample is set at the position of the origin O and is irradiated with an electron beam from the y-axis direction. The X-ray emitted from the sample in the X-axis direction is dispersed at the point T on the X-axis by the spectroscopic element 4 that is slidable in the X-axis direction and converges at the point P of the detector 5. The light-splitting element 4 is mounted on the moving member 11, and the movement of the light-splitting element 4 in the X-axis direction is performed by moving the moving member 11 along the moving shaft 6 installed in the X-axis direction. For the movement of the moving member 11, for example, the moving shaft 6 is constituted by a lead screw, the lead screw is rotated to feed the lead nut in the axial direction, and the moving member 11 fixed to the lead nut is moved in the axial direction. It is done by Then, the movement of the moving member 11 causes the spectroscopic element 4 and the moving shaft 9 fixed to the moving member 11 to move.

On the other hand, the detector 5 is mounted slidably along a link groove 8 fixed to the apparatus, and the shape of the link groove 8 is the polar coordinate r = 2Rsin2θ shown in the mechanism (A). It is formed according to the curve shown.

Further, the moving member 11 has on its extension a moving shaft 9 which is curved at an angle ψ with respect to the X axis, and can be slid with respect to the moving shaft 9 by a point S of the detector 5. The link mechanism (B) is formed by engaging with. That is, the moving shaft 9 is rotatably supported by the same shaft as the spectroscopic element 4 and moves together with the moving member 11, and restrains the detector 5 in a linear motion and detects the detector 5.
The slit is always directed toward the spectroscopic element 4.

Next, in FIG. 3, in order to converge the X-ray reaching the spectroscopic element on the point T to the point P, the distance between the origin O and the point T and the distance between the point T and the point P are shown. 2 shows a wire mechanism which is an embodiment for realizing a link mechanism (B) in which both distances are t.

In FIG. 3, the wire 12 is moved from the wire fixing portion 13 installed at one end of the apparatus to a point T on the moving member 11.
, The coil is wound around the shaft installed at the point T, and then the shaft installed at the point P of the detector 5 is wound, passed through the point T again, and is fixed to the wire fixing portion 13. This wire 12 has a spring 14
Due to this, a constant tension is applied, a constant load is applied to the detector 5 rearward, and the detector 5 is pulled to prevent loosening. The spring 14 in the figure is simply shown and does not necessarily apply a constant load. Further, the slit of the detector 5 is arranged on the point P in FIG. Then, as an initial setting, the distances between the origins O and T are set equal.

FIG. 2 shows the link mechanisms C and D. The link mechanisms C and D, for example, on the back side of the plate 15, do not interfere with the operation of the link groove 8 and the moving shaft 9, for example. It is composed of a link groove 18 and a link 17. The link groove 18 is formed in the plate 15 at an angle of ψ with respect to the axis X, and the link 1
7 has a length of 2Rsin2ψ and is formed by fixing one end to the link groove 18 and the other end to the spectroscopic element 4 at an angle ψ. The link groove 18 and the link 1
The link mechanisms C and D according to 7 are not limited to this configuration, and can be configured with other configurations.

[Operation of Embodiment] Next, the operation of the embodiment of the present invention will be described.

In FIGS. 1 and 2, when an electron beam is incident on the sample in the y direction, the X-ray emitted from the sample in the X-axis direction is dispersed in the spectroscopic element 4 on the X-axis. At this time, the spectroscopic element 4 uses the link mechanism (A) and the link mechanism (B) to set the origin O on the sample and the point P of the detector 5.
At the same time, they are arranged on the same Rowland circle, and the mounting angle of the spectroscopic element 4 is such that it is in contact with the Rowland circle by the link configuration (D), and the X-ray is directed toward the detector 5.

In this structure, since the link mechanism is fixed to the plate 15, large parts do not move, the operation is stable, and the adjustment is easy. Further, in the link configuration (D), the angle ψ formed by the X axis and the link groove 18 is made smaller than the angle α formed by the X axis and the sample surface, so that the position where the link mechanism (D) is closed supports the sample and the sample. The sample stage for the movement can be set at a position where it does not interfere, and a large sample or sample stage can be used.

On the other hand, the position and orientation of the detector 5 with respect to the X-rays are determined by the link mechanism (A) and the link mechanism (B) between the distance between the sample and the spectroscopic element and between the spectroscopic element and the detector. While keeping the distances equal, the orientation of the slit of the detector 5 is oriented in the direction of the spectroscopic element 4 which is the angle θ direction at the point P in FIG.

In the present invention, the spectroscopic element means a collection of a dispersive crystal, a multilayer film, a diffraction grating and the like.

The present invention is not limited to the above embodiments, and various modifications can be made within the spirit of the present invention, which are not excluded from the scope of the present invention.

[0047]

As described above, according to the present invention,
The configuration for arranging the spectroscope around the X-ray generation point should not affect the size of the sample or the position where the mechanism for supporting and moving the sample is installed, and to make the movable range of the spectroscopic element large. It is possible to provide an X-ray spectrometer capable of performing the above.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a mechanism of an X-ray spectrometer of the present invention.

FIG. 2 is a configuration diagram illustrating a mechanism of the X-ray spectrometer of the present invention.

FIG. 3 is a wire connection diagram of the X-ray spectrometer of the present invention.

FIG. 4 is a diagram illustrating the principle of the mechanism of the X-ray spectrometer of the present invention.

FIG. 5 is a diagram illustrating the principle of the mechanism of the X-ray spectrometer of the present invention.

FIG. 6 is a configuration diagram of a conventional X-ray spectrometer.

[Explanation of symbols]

1 ... Sample, 2 ... Electron beam, 3 ... Sample stage, 4 ... Spectroscopic element, 5 ... Detector, 6 ... Motion axis, 7, 17 ... Link, 8, 1
8 ... Link groove, 9 ... Moving shaft, 10 ... Arc, 11 ... Moving member, 12 ... Wire, 14 ... Spring, 15 ... Plate,

Claims (1)

[Claims] 1. An X-ray spectroscope that performs spectroscopic analysis by a spectroscopic element that moves on a linear axis passing through an origin, where (a) R is the radius of a Rowland circle and the linear axis is an angle of θ = 0, polar coordinates a first link mechanism having a curve represented by r = 2Rsin2θ or a part thereof as a locus, and (b) a distance from an origin to the spectroscopic element and the spectroscopic element to a detector on the first link mechanism. And a second link mechanism for constraining the distance to be equidistant, and (c) a length having one end as a point of the spectroscopic element and a point on a straight line passing through the origin and forming an angle with the linear axis as ψ as the other end. An X-ray spectroscope having a third link mechanism composed of a straight line of 2 Rsin ψ.