JPS6361615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray spectrometer used in an X-ray microanalyzer, and more particularly to an X-ray spectrometer in which a spectroscopic crystal and an X-ray detector are movable.

Prior art for this invention includes, for example, the US patent
There is USPat.No.3906225: X-Ray Spectrometer (hereinafter referred to as literature). Figure 6 is the first part of this document.
This is an explanatory diagram showing a conventional apparatus, and in the figure, 50 is a sample, R is a Roland circle, and S is a sample 5.
0 is the point where X-rays are emitted, that is, the X-ray source, 1 is the spectroscopic crystal, C is the center point of the spectroscopic plane of spectroscopic crystal 1, 6
is an X-ray detector. Further, 51 is a support plate, one end of which is connected to the spectroscopic crystal 1 at point C and is configured to move on a straight line 52, and the other end is configured to move on a straight line 53 at point M. .

When electrons collide with the sample 50, X-rays are emitted from the point S, are reflected by the spectroscopic crystal 1 (including diffraction by atoms, but simply referred to as reflection hereinafter), and are input to the X-ray detector 6, thereby emitting X-rays from the sample. Characteristic X-rays generated from 50 are measured. The point S, the center point C of the reflective surface of the spectroscopic crystal 1, and the surface D of the X-ray detector 6 must be arranged on the same circumference of the Rowland circle R, and the radius of the Rowland circle R must be r is spectroscopic crystal 1
must be 1/2 the radius of curvature of the reflecting surface.
In Fig. 6, the dashed line indicates that in order for the X-rays reflected at both ends of the spectroscopic crystal 1 to be focused at the point D together with the X-rays reflected at the point C, the radius of curvature of the spectroscopic crystal 1 must be 2r. This shows that this is not the case. The device shown in FIG. 6 is configured such that point M is also on the Rowland circle. If the center of the Rowland circle is P, then ∠CSM=1/2∠CPM=j, and the length CM is CM=2r・sinj, and this relationship holds regardless of the movement of point C. Therefore, the tangent direction at point C of spectroscopic crystal 1 is
If the spectroscopic crystal 1 is fixed to the support plate 51 so as to form an angle j with respect to the direction of CM, the straight line 52
At any position above, the normal at point C points toward the center point of the Rowland circle. However, as point C moves, the center point of the Rowland circle moves. This trajectory becomes a circular arc Q with radius r centered at point S. Point D moves in accordance with the movement of point C, and a mechanism (not shown) for moving the X-ray detector 6 in conjunction with the support plate 51 is provided.

However, in the conventional device, the radius r of the Rowland circle R
The problem was that it was fixed and could not be changed. The apparatus shown in FIG. 6 cannot be used for spectroscopic crystals with different radii of curvature, and if the radius of curvature has an error due to machining accuracy, the focal point will change. In other words, if the radius of curvature of the spectroscopic crystal changes, the radius r of the Rowland circle must also change accordingly, and conventional devices in which r is fixed have a problem in this respect. The present invention has been made in order to solve the above-mentioned problems in the conventional ones.

In the present invention, a moving body is provided that is moved by a moving mechanism different from the moving mechanism for the spectroscopic crystal 1, and this moving body is connected to a guide arm so that the radius of the Rowland circle can be arbitrarily selected. did.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing one embodiment of the specific invention of the present application. In the diagram, the same reference numerals as in FIG. 6 indicate the same or corresponding parts, and in FIG. Determine the coordinates, set the point of X=a, Y=0 as point A, and set the point of X=0, Y=b as point B,
Line SA is the first line 5, line BA is the second line 10
shall be. 2 is a first moving table, 3 is a rotating arm, 4 is a first guide, 7 is a guide arm, 8 is a second moving table, and 9 is a second guide. The first guide 4 is the first
The first movable table 2 is arranged in the direction of a straight line 5 and is configured to move on a first guide 4 . The rotating arm 3 is an arm for rotating the spectroscopic crystal 1, and the rotating arm 3 is an arm for rotating the spectroscopic crystal 1.
It is rotatably supported by the first moving table 2 at.
The spectroscopic crystal 1 is fixed to the rotating arm 3 so that the normal to the surface at point C is perpendicular to the direction of the rotating arm 3. The actual device is Z perpendicular to the XY plane.
It goes without saying that it has a dimension in the axial direction, and therefore, in the explanation of this specification, for example, when point C is referred to, it means that the projection onto the XY plane is point C. Guide arm 7 is at point C
It is rotatably attached to the first moving table 2 at. The second moving table 8 moves on the second guide 9 along the second straight line 10 and slidably holds the guide arm 7. The X-ray detector 6 is fixed to the second movable table 8.

Further, 11 is a first auxiliary arm, and 12 is a second auxiliary arm. The first auxiliary arm 11 is connected to the first straight line 5
The second auxiliary arm 12 is movably attached to the first moving table 2 at a point E that is a distance CE away from the point C, and the second auxiliary arm 12 is movably attached to the point F that is a distance CF that is equal to the distance CE from the upper point C of the guide arm 7. Rotatably attached to the guide arm. The length FG is made equal to CE, the length EG is made equal to CF (=CE), and the first auxiliary arm 11 and the second auxiliary arm 12 are connected at a common end point G to form a rhombus CFGE. The rotating arm 3 is slidably supported at a point G.

Note that P is the center of the Rowland circle, and 2θ is the angle that SC makes with respect to point P.

If the coordinates of point C are X=Xc, Y=0, then Xc=2r・sinθ...(1), and the second straight line 10 can be expressed as Y=-bX/a+b...(2), and the guide Since the point on arm 7 can be expressed as Y=(X-Xc)tan2θ...(3), the point on the guide arm 7 and the second
The coordinates of the intersection H of the straight line 10, X=Xh, Y=Yh, are expressed by formula (2)
and (3), the distance from point B to point H is BH = {Xh ² + (Yh - b) ² } ^1/2 = (a ² + b ² ) ^1/2 (Xc・tan2θ+b) /(a・tan2θ+b) (4), and the distance SC from the X-ray source S to point C is SC=Xc=2r・sinθ (5).

Therefore, in this spectrometer, when the required values are given for the radius of curvature 2r of the spectroscopic crystal 1 and the spectroscopic angle θ, the first moving stage 2 is moved to the point Xc determined by equation (5). Then, the distance BH determined by equation (4) is calculated, and the second moving table 8 is moved to the point H. In this way, it is possible to set the values of θ and r that satisfy both equations (4) and (5).

In order to calculate SC and BH from equations (4) and (5) and control the movement of the first moving platform 2 and the second moving platform 8 according to the calculation results, any known arithmetic control circuit ( (not shown) may also be used.

Also, θ changes due to the movement of point H, but CE
From the relationship =EG=CF=FG, ∠ACH=∠ECF=2∠ECG=2θ∠ECG=θ
...(6), and the rotating arm 3 can be rotated while satisfying equation (6). The portion that operates by the first auxiliary arm 11 and the second auxiliary arm 12 to satisfy the relationship of equation (6) is referred to as a rotation angle adjusting means.

Therefore, if the radius of curvature of the spectroscopic crystal 1 is 2r, the X-rays generated at the point S, while satisfying the Bragg condition, enter the spectroscopic crystal 1 at the spectroscopic angle θ and then are reflected onto the guide arm 7. The light is always focused on point D where SC=CD (7).

In the above-mentioned spectrometer, the first moving table 2 and the second moving table 8 are moved individually to determine the distance SC (=Xc) and the distance
Since BH can be set independently of each other, the two variables r and θ in equations (4) and (5) can be chosen to arbitrary values, and the spectral wavelength of the same spectroscopic crystal can be freely set. Can be set. Also, the radius of curvature 2r of the spectroscopic crystal 1
Even if there is a machining error, it is possible to individually move the first moving table 2 and the second moving table 8 to obtain r and θ that satisfy the Bragg condition.

FIG. 2 is an explanatory diagram showing another embodiment of the specified invention, in which the same symbols as in FIG. 1 indicate the same or corresponding parts, 10' is parallel to the second straight line 10,
a distance BB′ or AA′ equal to the distance CE in the X direction,
The second guide 9 is provided on the third straight line 10', and the second moving table 8 is a third straight line separated by HH'.
moves on the second guide 9 on the third straight line 10',
The first auxiliary arm 11 is slidably held.
F′G′ shown with reference numeral 12 in Fig. 2 is the second auxiliary arm.
It is installed parallel to the FG to reinforce the arm FG, and B′H′=BH, and the adjustment of B′H′ is by the formula
This can be done in accordance with (4).

FIG. 3 is an explanatory diagram showing still another embodiment of the specified invention of the present application, in which the same reference numerals as in FIG. Except for rotating the guide arm 7, the first
This is similar to the embodiment shown in the figure.

FIG. 4 is a schematic plan view showing a specific example of the configuration shown in FIG. 2. In the figure, the same reference numerals as in FIG. 21 is a threaded rod, 22 and 23 are gears, 24 is a pulse motor, 25 is a flange, 26 is a long hole, 2
7 is a shaft that slidably engages with the long hole 26, 28 is a threaded rod, 29 is a long hole, 30 is a frame, 31 is a shaft that is engaged with the long hole 29, 32 and 33 are gears, and 34 is a pulse motor. , 35, 36, 37 are pulleys, 38,
39 is a rope, 40 is a coil spring, and 41 is a pin. The first moving table 2 is moved along the first guide 4 via the gears 22 and 23 and the threaded rod 21 from the pulse motor 24, and the gear 3 is moved from the pulse motor 34.
2, 33, the second moving table 8 is moved along the second guide 9 via the threaded rod 28. The rope 38 and coil spring 40 eliminate looseness during movement. 2 between the rotating arm 3 and the first auxiliary arm 11
6, 27 and the first auxiliary arm 11
The sliding engagement of 29 and 31 between the second movable table 8 and the second movable table 8 constitutes a rotation angle adjusting means. In the embodiment shown in FIG. 4, the portion indicated by FG in FIG. 2 is omitted. It is clear that if the F′G′ part is present, the FG part can be omitted.

FIG. 5 is an explanatory diagram showing an embodiment of the second invention of the present application, in which the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and 50 and 51 are provided corresponding to the threaded rod 21. Limit switch, 52, 53
is a limit switch provided corresponding to the threaded rod 28. 54 is a motor, 55 and 56 are gears,
57 is a limit switch that detects the amount of rotation of the motor 54, 60 is the motor 54, and 61 is the motor 24.
and 62 are drive circuits for the motors 34, respectively. Drive circuits 60, 61, and 62 are individually controlled by corresponding control circuits 64, 65, and 66, respectively.

63 is limit switch 50, 51, 52, 5
Control circuits 64 and 6 based on the detection signals of 3 and 57
5 and 66 are processing circuits that provide control information; 67 is a pulse generator that generates pulses to drive the motors 24, 34, and 54 when they are pulse motors; 68 is a console; and 69 is a calculation control circuit 70. Data to be stored and each control circuit 64, 65, 66
70 is an arithmetic control circuit, and 71 is a memory attached to the arithmetic control circuit. From the operation console 68, θ, r, a,
b, tan2θ values, X-ray wavelength λ, operation command, reset command, etc. are input to the arithmetic control circuit 70.

The motor 54, the gears 55, 56, and the holding mechanism for the spectroscopic crystal 1 connected to the gear 56 are referred to as an automatic spectroscopic crystal switching means. The parts of the device shown in Fig. 5 other than the automatic switching means shown in Fig. 4 are electrical circuits for controlling the parts shown in Fig. 4, and will be easily understood from the explanation of Figs. 2 and 4. This is possible, so we will omit the redundant explanation.

Spectroscopic crystal automatic switching means 54, 55, 56
Regarding FIG. 5, only one spectroscopic crystal 1 is shown to make the drawing easier to understand, but the gear 56
A plurality of spectroscopic crystals having different radii of curvature are attached to the member connected to the motor 54.
By rotating, one arbitrarily selected one of the plurality of spectroscopic crystals mounted can be fixed to the first movable table 2. With conventional equipment, it is difficult to change the radius of the Rowland circle, so it cannot be used for measurement simply by replacing a spectroscopic crystal with a different radius of curvature, so conventional equipment does not automatically replace the spectroscopic crystal. Nakatsuta.

However, as is clear from equation (5), being able to change r means being able to change Xc for the same θ; decreasing Xc increases the X-ray intensity, and increasing Xc increases the wavelength resolution. Therefore, from these two considerations, the specific invention of the present application is capable of easily changing the radius of the Rowland circle, and the second invention of the present application is capable of easily changing the radius of the Rowland circle and the radius of curvature of the spectroscopic crystal. The invention has the effect of significantly improving the flexibility of use of an X-ray spectrometer.

〔Effect of the invention〕

As described above, according to the specific invention of the present application, in the X-ray spectrometer, the radius of the Rowland circle corresponding to the spectral angle and the radius of curvature of the spectroscopic crystal can be adjusted separately, so that According to the second invention of the present application, since the spectroscopic crystal can be easily replaced, the distance from the X-ray source to the spectroscopic crystal can be reduced to increase the intensity of the X-rays. , or conversely, it has the effect of facilitating adjustments such as increasing the distance to improve wavelength resolution.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the specific invention of the present application, FIG. 2 is an explanatory diagram showing another embodiment of the above invention, FIG. 3 is an explanatory diagram showing still another embodiment of the above invention, 4 is a schematic plan view showing a specific example of the structure shown in FIG. 2, FIG. 5 is a block diagram showing the second invention of the present application, and FIG. 6 is a block diagram showing a conventional device. 1: Spectroscopic crystal, 2: First moving table, 3: Rotating arm, 6: X-ray detector, 7: Guide arm, 8: Second moving table, 11: First auxiliary arm, 12: Second auxiliary arm . 54, 55, 56: Automatic switching means for spectroscopic crystals. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A point S on the sample serving as an X-ray source, a spectroscopic crystal,
In an X-ray spectrometer that performs spectroscopy of characteristic X-rays generated from the sample by arranging an X-ray detector and an X-ray detector on the circumference of the same Roland circle, At these coordinates, a first straight line 5 connecting point A and point S at X=a, Y=0, and point B at X=0, Y=b.
Assuming a second straight line 10 connecting and point A,
a first configured to move on the first straight line;
moving table 2, a point C on the first straight line 5 of this first moving table 2;
a rotating arm 3 that is rotatably supported around the center; a spectroscopic crystal 1 that is fixed to the rotating arm 3 and whose surface normal at point C is arranged at right angles to the direction of the rotating arm; point C; A guide arm 7 is rotatably supported around the guide arm 7;
ray detector 6, a second moving table 8 configured to move the X-ray detector 6 on the second straight line 10, a driving means for moving the first moving table 2 and the second moving table 8. , a rotation angle adjusting means that always maintains a rotation angle of the guide arm 7 with respect to the first straight line 5 to be twice the rotation angle of the rotation arm 3 with respect to the first straight line 5; The moving angle adjustment means is rotatably mounted on the first straight line 5 of the first movable table 2 about a point E that is separated from a point C by a distance CE, and has a length
a first auxiliary arm 11 in which EG is equal to the distance CE;
and a second auxiliary arm 12, which is rotatably attached around a point F whose distance CF from the upper point C of the guide arm 7 is equal to the length EG, and whose length FG is equal to the distance CE. , said first and second
X-ray spectroscopy characterized by comprising: rotation angle adjusting means configured to connect the terminal ends of the auxiliary arms so that this connection point is G, and to slidably hold the rotation arm 3 at the point G. Device. 2. A patent characterized in that the second moving table 8 is slidably connected to the guide arm 7 and configured to hold the X-ray detector 6 and move on the second straight line 10. X described in claim 1
Line spectrometer. 3 The second moving table 8 is connected to the first auxiliary arm 1
1 on the extension of said X on said guide arm 7
slidably attached to the extension of the first auxiliary arm 11 at a position spaced apart from the position of the line detector 6 in the X direction by a distance equal to the distance CE;
Claim 1 characterized in that it is configured to move on a third straight line parallel to the second straight line 10 and spaced from the second straight line 10 in the X direction by a distance equal to the distance CE. X-ray spectrometer. 4. The second moving table 8 is slidably attached to the extension of the rotating arm 3 and is configured to move on the second straight line 10. The X-ray spectrometer according to item 1. 5 The driving means calculates the respective positions to which the first moving table 2 and the second moving table 8 should be moved from the conditions given to the spectroscopic device, that is, the radius of curvature and the spectroscopic angle of the spectroscopic crystal, and calculates the respective positions to which the first moving table 2 and the second moving table 8 should be moved, and calculates the calculation results. Claim 1, further comprising an arithmetic control circuit for controlling the movement of the first and second movable tables.
The X-ray spectrometer described in Section 1. 6 A point S on the sample that serves as an X-ray source, a spectroscopic crystal,
In an X-ray spectrometer that performs spectroscopy of characteristic X-rays generated from the sample by arranging an X-ray detector and an X-ray detector on the circumference of the same Roland circle, At these coordinates, a first straight line 5 connecting point A and point S at X=a, Y=0, and point B at X=0, Y=b.
Assuming a second straight line 10 connecting and point A,
a first configured to move on the first straight line;
moving table 2, a point C on the first straight line 5 of this first moving table 2;
a rotating arm 3 that is rotatably supported around the center; a spectroscopic crystal 1 that is fixed to the rotating arm 3 and whose surface normal at point C is arranged at right angles to the direction of the rotating arm; point C; A guide arm 7 is rotatably supported around the guide arm 7;
ray detector 6, a second moving table 8 configured to move the X-ray detector 6 on the second straight line 10, a driving means for moving the first moving table 2 and the second moving table 8. , a rotation angle adjusting means that always maintains a rotation angle of the guide arm 7 with respect to the first straight line 5 to be twice the rotation angle of the rotation arm 3 with respect to the first straight line 5; The moving angle adjustment means is rotatably mounted on the first straight line 5 of the first movable table 2 about a point E that is separated from a point C by a distance CE, and has a length
a first auxiliary arm 11 in which EG is equal to the distance CE;
and a second auxiliary arm 12, which is rotatably attached around a point F whose distance CF from the upper point C of the guide arm 7 is equal to the length EG, and whose length FG is equal to the distance CE. , said first and second
Rotation angle adjusting means configured to connect the terminal ends of the auxiliary arms so that this connection point is G, and to slidably hold the rotary arm 3 at point G; a plurality of spectroscopic crystals having different radii of curvature; X-ray spectroscopy characterized by comprising automatic switching means 54, 55, and 56 for holding a spectroscopic crystal and automatically mounting one spectroscopic crystal arbitrarily selected from among the spectroscopic crystals on the first moving table 2. Device.