JP2668371B2 - Slit control mechanism of X-ray diffractometer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a slit control mechanism of an X-ray diffraction apparatus,
In particular, the present invention relates to a slit control mechanism that can be used for both slit width adjustment in which the slit width is changed in accordance with an incident angle θ of an X-ray incident on a sample surface and optical axis adjustment by moving the slit. [Prior Art] In an X-ray diffractometer, a technique of changing a slit width in accordance with an incident angle θ of X-rays incident on a sample surface and thus constantly irradiating a constant sample range with X-rays is already known. (Eg, Japanese Patent Publication No. 50-40676 and Japanese Patent Publication No. 53-28222)
No.). Referring to FIG. 8, the X-rays emitted from the X-ray focal point 60 pass through the divergence slit 62 and pass through the sample 64.
And the diffracted X-rays are collected at the light receiving slit 66. At this time, even if the X-ray incident angle θ changes, the slit width b of the divergent slit 62 is adjusted according to the incident angle θ so that the X-ray is always irradiated to the full width a of the sample 64. do it. The width of the sample 64 viewed from the X-ray focal point 60 is a ·
Since sin θ is obtained, if the slit width b is changed in proportion to sin θ, the irradiation range of the sample becomes constant without depending on θ with a very good approximation. On the other hand, as a technique separate from adjustment of the slit width, there is an optical axis adjustment technique of a goniometer of an X-ray diffraction apparatus. The optical axis adjustment of a goniometer is generally performed in the following procedure. (A) When the rotation angle (2θ) of the detector arm is set to zero, the divergence slit, the rotation axis of the sample stage (hereinafter, referred to as the sample axis), and the light receiving slit on the detector arm are aligned. Adjustments to come. This adjustment has already been adjusted at the manufacturing stage of the goniometer. (B) X-ray so that the X-ray focus is on the optical axis of the goniometer
Adjustment that determines the relative positional relationship between the line focus and the goniometer. This adjustment is done by rotating the goniometer base slightly.
It is adjusted so that the output of the X-ray detector becomes maximum. (C) Confirmation of 2θ = 0. This check is performed as follows. The detector arm is slightly rotated near 2θ = 0 to obtain a peak profile, and the midpoint of the half-value width of the detected peak is set as the zero peak position. Next, it is confirmed that the deviation between the position of the zero peak and the position of the zero mark on the detector arm base is within a predetermined angle range.
If it does not heal within the predetermined angle range, the above (b)
You will have to start over from the adjustment. (D) Adjustment of the rotation angle (θ) of the sample table = zero. This adjustment is performed such that the sample stage is slightly rotated near θ = 0 and the output of the X-ray detector is maximized. This adjustment is performed by attaching an optical axis adjustment jig to the sample table. The reference plane of this jig is in the plane including the sample axis, and θ =
Near zero, the reference plane is parallel to the incident X-ray. In such an optical axis adjustment, the heavy goniometer base is slightly rotated in the adjustment of (b). [Problems to be Solved by the Invention] In recent years, there has been an increasing demand for automating the optical axis adjustment of a goniometer. As one measure for this purpose, the optical axis can be adjusted only by moving the slit position without rotating the goniometer base. There are attempts to make adjustments. In this way, it is sufficient to move the light slit without moving the heavy goniometer base. Then, a mechanism for moving the slit is necessary for both slit width adjustment and optical axis adjustment by slit movement, and if these are provided as separate mechanisms, the mechanism near the slit will not be complicated. Inevitable. Accordingly, it is an object of the present invention to provide a slit control mechanism that enables optical axis adjustment by slit movement and slit width adjustment. [Means for Solving the Problems] A slit control mechanism according to the present invention is an X-ray diffractometer of a type that measures a diffraction peak by changing an incident angle θ of an X-ray incident on a sample surface. It is characterized by having. (A) The slit for passing X-rays is composed of two slit plates. (B) The control mechanism includes a fixed bracket and a movable member movable with respect to the fixed bracket. (C) The two slit plates are attached to the moving member, and the slit plates are driven by a slit control motor fixed to the fixed bracket, whereby the slit width is adjusted. (D) The slit control motor rotates in proportion to the θ rotation motor for changing the incident angle θ when adjusting the slit width. (E) When the slit width is at the minimum interval, the moving member is movable with respect to the fixed bracket by rotation of the slit control motor. This slit control mechanism has two basic functions. First, for slit width adjustment, the slit width is
It changes in proportion to sin θ. In the slit movement for adjusting the optical axis, the slit control motor is rotated while keeping the slit width at the minimum distance, and the moving member itself having the slit plate is moved with respect to the fixed bracket. Thereby, the slit plate having the minimum interval moves in a plane perpendicular to the optical axis, and the optical axis can be adjusted using this movement. That is, the slit width adjusting operation and the slit moving operation can be performed by one slit control motor, and the mechanism can be simplified. The slit control mechanism of the present invention, for that purpose,
Basically, it is applied to the divergence slit of an X-ray diffractometer.
However, when it is necessary to control both the adjustment of the slit width and the movement of the slit position, the present invention can be applied to another slit such as a scattering prevention slit. Embodiment FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is a side view thereof. The slit control mechanism includes a fixed bracket 10 and a movable member 11 movable with respect to the fixed bracket 10. First, a mechanism for adjusting the slit width will be described.
Two parallel four-bar linkages are attached to the moving member 11. The first parallel four-joint link mechanism includes a moving member 11 which is a stationary joint, a driving joint disk 12, a driven joint disk 14, and an intermediate joint member 16. The second parallel four-bar linkage is
It comprises a moving member 11 which is a stationary joint, a common driving joint disk 12, a common driven joint disk 14, and a separate intermediate joint member 18.
The respective nodes of the parallel four-bar linkage are connected to each other by a rotating pair. And, these two parallel four-bar linkages,
It is configured to be point-symmetric with respect to the middle point of the stationary node, that is, an intermediate point 21 (see FIG. 4) between the driving node disk 12 and the driven node disk 14. The point symmetry means that the basic structure of the mechanism is point symmetric, and does not mean that the specific shape of the intermediate node member or the like is point symmetric. Slit plates 20 and 22 are fixed to the intermediate joint members 16 and 18, respectively. Driven joint disc 14 and intermediate joint
16 and a connection point between the follower disk 14 and the intermediate node 18
The distance d to 17 (the same applies to the motor disc 12) gives the maximum value of the slit width. Stopper 23 on slit plate 20
Are formed, and the slit plate 22 comes into contact with the stopper 23 and stops. At this time, the interval between the slit plates 20 and 22, ie, the slit width, does not become completely zero but becomes the minimum interval c. This minimum interval c is set to 0.05 mm in this embodiment. In FIG. 2, one intermediate node member 18 and the slit plate 22 fixed thereto are not shown for clarity. The drive node disc 12, as best shown in FIG.
The worm wheel 26 is fixed to the worm wheel 26, and the worm wheel 26 is fixed to the shaft 24. The shaft 24 is rotatably supported by the moving member 11 by a bearing 28. Driven disc 14
Is fixed to a shaft 30, and the shaft 30 is also rotatably supported by the moving member 11 by a bearing 32. The worm wheel 26 described above meshes with a worm 34, and the worm 34 is a slit control pulse motor.
Fixed to 36 output shafts. The slit control pulse motor 36 is fixed to the fixed bracket 10. This slit control pulse motor 36 rotates in proportion to a θ rotation pulse motor (not shown) for rotating the sample stage. The proportionality constant is set so that the rotation angle of the motor-joint disk 12 is equal to the incident angle θ of the X-ray incident on the sample. Specifically, the number of pulses per unit time supplied to the θ-rotation pulse motor is multiplied by this proportionality constant, and the obtained value is defined as the number of pulses per unit time supplied to the slit adjustment pulse motor 36. good. A starting disk 38 is fixed to the other end of the shaft 24, and a starting disk 40 is also fixed to the other end of the other shaft 30. That is, starting disks 38 and 40 are arranged on the back of the slit control mechanism. As shown in FIG. 3, a connecting member 42 is connected to the starting disks 38 and 40 by a rotating pair. As a result, the activation disks 38 and 40, the connecting member 42, and the moving member 11 constitute a third parallel four-bar linkage. The third parallel four-bar linkage is 90 degrees out of phase with the two parallel four-bar linkages described above. That is, in the two parallel four-joint link mechanisms described above, the driving joint disk 12 and the driven joint disk
When the connection points 15, 17 between the 14 and the intermediate joint members 16, 18 come on a line connecting the center of the driving joint disk and the center of the driven joint disk,
In the third parallel four-bar linkage, the connecting point 39 between the starting disk 38 and the connecting member 42 is on a horizontal line passing through the starting disk 38 and the connecting point 39 between the starting disk 40 and the connecting member 42. 41 is
It will be on a horizontal line passing through the activation disk 40. With such a configuration, even when the above-described two parallel four-bar linkages reach the position of the dead center, the operation of the third parallel four-bar linkage enables the adjustment mechanism to function normally. Has become. Next, a mechanism for moving the slit position will be described. FIG. 5 is a partially deleted front view of FIG. 1 with parts related to the parallel four-bar linkage removed.
FIG. 6 is a sectional view taken along line VI-VI of FIG. 5, and FIG.
FIG. 7 is a sectional view taken along line VII-VII of FIG. 5. FIG. 5 is a sectional view taken along line VV of FIG. First, in FIGS. 5 and 7, the moving member 11 is guided by a rolling guide mechanism 44 so as to be linearly movable with respect to the fixed member 46. That is, the moving member 11 can move in the left-right direction in FIG. The fixing member 46 is fixed to the fixing bracket 10. Through holes 43 and 45 shown in FIG.
Are for supporting the bearings 28 and 32 of FIG. Next, in FIG. 5 and FIG. 6, a clamp plate 48 made of a thin metal plate is fixed near the distal end of the moving member 11. On the other hand, a pressing plate 50 made of a thin metal plate is also fixed near the distal end of the fixing member 46. The fixing member 46 further has a clamp receiving portion 52 located on the back surface of the clamp plate 48. A through hole 54 is formed in the fixing member 46, and a clamp bar 56 is disposed therein. The clamp rod 56 is driven by an electromagnetic solenoid 58.
The electromagnetic solenoid 58 is normally in the OFF state. At this time, the clamp bar 56 presses the pressing plate 50 by the action of the compression coil spring 59. The pressing plate 50 further presses the clamp plate 48, and the clamp plate 48 is sandwiched and fixed between the pressing plate 48 and the clamp receiving portion 52. When the electromagnetic solenoid 58 is turned on, the clamp rod 56
It retracts against the compression coil spring 59. Next, the operation of this embodiment will be described. First, the slit width adjusting function will be described. First, it is assumed that the X-ray incident angle θ in FIG. 8 is zero. At this time, the two parallel four-bar linkages are in the state shown in FIG. That is, the slit width is the minimum interval c. In order to measure the diffraction peak, a predetermined pulse is supplied to the θ rotation pulse motor to rotate the sample stage. that time,
The slit control pulse motor 36 in FIG. 1 rotates in proportion to the θ rotation pulse motor. Slit control pulse motor
When the rotation of the worm wheel 36 and the worm wheel 26 is performed, the prime mover disc 12 rotates at an angle θ. Then, the parallel four-bar linkage mechanism connected to the driving joint disc 12 rotates in the direction of arrow 19. As a result, as shown in FIG. 4, the distance between the slit plate 20 fixed to the intermediate joint member 16 and the slit plate 22 fixed to the intermediate joint member 18 changes with the value of d · sin θ + c. Since the value of c is very small, the slit width changes almost in proportion to sin θ, and the sample range irradiated with X-rays is almost constant regardless of θ. Next, the slit moving operation for adjusting the optical axis will be described. First, the procedure for moving the slit position to adjust the optical axis will be described with reference to FIG. An optical axis adjusting slit 70 is attached to the sample table 68, and a reference surface 71 is set perpendicular to the optical axis. First, the divergent slit (controlled by the slit control mechanism according to the present invention) 62 is fully opened, and the X-ray focus
The detector arm base is slightly rotated in the vicinity of 2θ = 0 so that the light receiving slit 66 and the X-ray detector 72 are located on the extension of the straight line connecting the 60 and the optical axis adjusting slit 70. That is, at the time of this minute rotation, a position where the X-ray detection intensity is maximum is searched for. Then, the position is determined as the position of 2θ = zero. Next, the divergence slit 62 is kept at the minimum interval c,
By moving in a plane perpendicular to the optical axis, the slit position where the X-ray detection intensity is maximum is searched for. Then, the position of the divergence slit is fixed at that position. Next, the optical axis adjusting slit 70 is rotated clockwise by 90 degrees to align the reference plane 71 with the optical axis. In this state, the sample stage is slightly rotated to find the rotational position of the sample stage at which the X-ray intensity becomes maximum, and the position is determined as θ = 0. Thus, the optical axis adjustment is completed. Next, the actual movement of the diverging slit will be described. At this time, first, the worm 34 is rotated in the direction of arrow 25 in FIG. 2 to rotate the parallel four-bar linkage in the direction of arrow 19 in FIG. When the slit width is maximum, the parallel four-bar linkage cannot rotate any further.
At this time, the electromagnetic solenoid 58 shown in FIG. 6 is turned on. Then, the clamp rod 56 retracts, and the moving member 11 becomes movable. Thereafter, when the worm 34 is rotated in the same direction, the worm wheel 26 meshing with the worm 34 does not rotate, and the moving member 11 itself moves rightward in FIG. After the moving member 11 has passed the predetermined reference point, the slit control pulse motor 36 stops. At this point, the electromagnetic solenoid 58 in FIG.
Set to F to fix the moving member 11 at that position. And
The worm 34 is rotated in the direction opposite to the arrow 25 in FIG. Then, the parallel four-bar linkage rotates in the direction opposite to the arrow 19 in FIG. 1, and finally stops in the state shown in FIG. That is, the intermediate node member 18 stops upon hitting the stopper 23, and the slit width is in the state of the minimum interval c. When the slit width reaches the minimum interval, the electromagnetic solenoid 58 is turned on again, and the moving member 11 becomes movable. Then warm
When the member 34 is further rotated in the same direction, the moving member 11 moves to the left in FIG. 1 while keeping the slit width at the minimum interval. When the moving member 11 reaches a predetermined reference point, this point is defined as the origin of movement of the moving member 11 (datum point).
And Then, the worm 34 is further rotated in the same direction to perform the above-mentioned optical axis adjustment. That is, in order to search for the peak position of the X-ray, the slit position is always moved in a fixed direction (left direction in FIG. 1) from the reference position. When the peak position is determined, the moving member 11 is fixed at that position. The above operation completes the optical axis adjustment. When the optical axis adjustment is completed, the moving member 11 is kept fixed. And X
At the time of the line diffraction measurement, only the slit width adjustment described above may be performed. [Effects of the Invention] As described above, the present invention enables the slit width to be adjusted according to the incident angle θ of the X-ray incident on the sample, and furthermore,
Move the center position of the slit to enable optical axis adjustment,
Moreover, since these functions can be controlled by one slit control motor, there is an effect that the slit width adjustment and the optical axis adjustment by moving the slit can be performed by a simple mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of one embodiment of the present invention, FIG. 2 is a side view of this embodiment, FIG. 3 is a view taken along line III-III of FIG. FIG. 5 is a front view showing another operation state of this embodiment. FIG. 5 is a partially deleted front view of this embodiment, and is a cross-sectional view taken along line VV of FIG. 6, and FIG. 7 is a sectional view taken along the line VII-VII of FIG. 5, FIG. 8 is a conceptual view of the X-ray diffractometer, and FIG. 9 is an explanatory view of optical axis adjustment by moving a slit. . 10: Fixed bracket 11: Moving member 14: Driven discs 20, 22, Slit plate 36: Slit control pulse motor

Claims (1)

(57) [Claims] A slit control mechanism having the following configuration in an X-ray diffraction apparatus of a type that measures a diffraction peak by changing an incident angle θ of an X-ray incident on a sample surface. (A) The slit for passing the X-ray is composed of two slit plates. (B) The control mechanism includes a fixed bracket and a movable member movable with respect to the fixed bracket. (C) The two slit plates are attached to the moving member, and the slit plates are driven by a slit control motor fixed to the fixed bracket, whereby the slit width is adjusted. (D) The slit control motor rotates in proportion to the θ rotation motor for changing the incident angle θ when adjusting the slit width. (E) When the slit width is at the minimum interval, the moving member is movable with respect to the fixed bracket by rotation of the slit control motor.