JPH09166557A - X-ray optical axis adjusting method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm a position on the sample surface to be irradiated with X-ray safely and easily with accuracy by inversely injecting light toward an X-ray source, and detecting light scattered by X-ray transmission material or the like existing on an X-ray optical axis. SOLUTION: Light 5 is inversely made incident on an X-ray source 6 from a light source 3 installed on the layout face of an X-ray detector 2, that is, an X-ray optical axis face 1, in such a way as to pass the optical axis face 1 of the sample surface 4. The light 5 having passed outgoing slits 7, 8 of the X-ray source 6 is projected to window material 10 (X-ray transmission material) for taking out X-rays from target material 9. At this time, light 11 scattered on the surface of the window material 10 is detected by a photo detector 12. The inclination angle of the sample surface 4 in a sample position, and the optical axis face 1 in the position of the X-ray detector 2 are respectively moved to adjust an optical axis so that the intensity of the detected scattered light 11 becomes maximum. In this way of adjusting the optical axis, X-rays are not used, so that a worker is not exposed to X-rays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for safely, simply and accurately adjusting an X-ray optical axis in an analytical instrument utilizing X-rays in the industrial field or medical field.

[0002]

2. Description of the Related Art X-rays have been used for various purposes such as crystal structure analysis of substances, elemental analysis and internal diagnosis in the body for 100 years since they were discovered by X-ray. However, since X-rays are ionizing radiation, there are many safety regulations (Occupational Safety and Health Regulations and Ionizing Radiation Hazard Prevention Regulations) in handling them, and careful handling is necessary. In particular, it is necessary to pay close attention to aligning the X-ray optical axis, which is invisible light, unlike visible light.

Up to now, the operation of aligning the optical axis of the X-ray device has been carried out, for example, in an X-ray diffraction device, by placing a fluorescent plate or a photographic film at the X-ray irradiation position on the sample and visually observing the fluorescent portion. It has been carried out by a method such as confirming or attaching a jig called a half-value plate to the sample installation position and measuring the intensity of the transmitted X-ray.

Further, recently, an apparatus having a fully automatic optical axis adjusting function that automates these methods has come to be attached in various forms. Further, in a fluorescent X-ray analyzer, an optical axis measuring method using an X-ray total reflection phenomenon and a scintillation detector has also been tried (for example,
"Bunseki" (Journal of Japan Society for Analytical Chemistry), 1992, 2nd
No., p. 129-130).

However, all of these methods are actually X
This is done by generating a line, and an open-type device used on site has a risk of being exposed to an operator, regardless of the closed-type device. In addition, except for the optical axis adjusting method using a fluorescent plate or a photographic film, the method is performed by an X-ray detector, and it is not possible to directly check the position of X-ray irradiation on the sample.

[0006]

As described above, in the conventional X-ray optical axis adjusting method, since X-rays must be generated, there is a risk that the operator will be exposed to the X-rays, and the X-rays on the sample surface will be exposed. There is also a problem that it is difficult to directly confirm the irradiation position of the rays.

The present invention has been made in view of the problems of the prior art, and is an X-ray optical axis adjusting method which is safe for an operator and which can confirm the X-ray irradiation position on the sample surface, and its method. The purpose is to provide a device.

[0008]

SUMMARY OF THE INVENTION The gist of the present invention is an X-ray optical axis adjustment method in an analytical instrument using X-rays, which is performed by the following procedure.

Visible light rays are incident back to the X-ray source.

The visible light scattered by an X-ray transmitting substance (for example, a window substance) or an X-ray target on the X-ray optical axis is detected.

The sample position or the position of the X-ray detector is adjusted so that the intensity of the scattered visible light detected above becomes the strongest.

Further, the gist of the present invention is an X-ray optical axis adjusting device in an analytical instrument using X-rays, which is characterized by having the following configuration.

A visible light source which makes the X-ray source incident backwards.

A photodetector for detecting visible light scattered by an X-ray transmitting substance (for example, a window substance) or an X-ray target on the X-ray optical axis.

Movable means for adjusting the position of the sample or the position of the X-ray detector so that the detection intensity of the scattered visible light becomes the strongest.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION According to the method of the present invention, first, visible light is X-rayed.
The light is incident back toward the radiation source, and the scattered light generated inside the X-ray source at that time is detected. FIG. 2 is a schematic diagram illustrating the relationship between the visible light source, the sample, the X-ray source, and the optical axis plane in the method of the present invention. Further, FIG. 3 is a longitudinal sectional view of the X-ray source showing a mechanism for detecting visible light scattered inside the X-ray source necessary for carrying out the method of the present invention.

The operation procedure from the reverse incidence of visible light on the X-ray source to the detection of scattered light will be described below with reference to FIGS. 2 and 3.

2 and 3, reference numeral 2 is an X-ray detector, 3 is a visible light source, 4 is the sample surface, 5 is visible light, and 6
Is an X-ray source, 7 and 8 are X-ray emission slits, 9 is a target material, 10 is a window material, 11 is scattered visible light [hereinafter referred to as scattered visible light], and 12 is a photodetector.

As shown in FIG. 2, the light from the visible light source 3 installed on the arrangement plane of the X-ray detector 2, that is, the X-ray optical axis plane 1 [hereinafter referred to as the optical axis plane 1] or directly from the sample surface 4 or the like. Visible light rays 5 are incident back toward the X-ray source 6 so as to pass through the axial plane 1. As the visible light in this case, it is desirable to use a low-power laser light source because detection becomes easy when scattered with high brightness.

As shown in FIG. 3, the normal X-ray source 6 has an X-ray generator for the target material 9 and two emission slits 7 and 8 arranged in a straight line in order to extract the X-rays to the outside. . Therefore, the visible light 5 that has passed through the X-ray limiting exit slits 7 and 8 of the X-ray source 6 is applied to a window material 10 made of Be or the like in order to extract X-rays from the target material 9 of the X-ray source. It At this time, visible light 11 scattered on the surface of the window material 10 is detected by a photodetector 12 such as a photodiode.

When the window material 10 is not used, there is no problem even if the scattered light is detected on the surface of the target material 9 or by inserting the X-ray transmitting material on the optical axis of the X-ray. .

Next, in order to maximize the intensity of the scattered visible light 11 detected in this way, the sample position is the tilt angle (tilt) of the sample surface 4, and the X-ray detector position is the optical axis plane. Adjust the optical axis by moving 1 respectively. In this case, the number of axes to be set differs depending on the optical system. For example, in the case of an ordinary diffractometer (X-ray diffractometer) in X-ray diffraction, that is, a device in which the X-ray detector and the sample need to be rotated on the same drive axis, the X-ray detector 2 is used as an optical detector. It is necessary to scan along the axial surface 1, and the incident direction of the visible light ray 5 is not limited to one direction but from a plurality of directions,
It is desirable to adjust each drive unit so that the X-ray source 6, the X-ray detector 2, and the sample surface 4 are arranged on the optical axis plane.

There is also a method of detecting the intensity of the scattered visible light 11 by using an optical fiber or the like and using a photomultiplier tube or the like provided outside the X-ray source 6. If the visible light 5 to be used is interrupted at a specific frequency by a chopper or the like and is incident back to the X-ray source 6 and signal processing is performed via a lock-in amplifier so as to be tuned to this frequency, stray light or a photodetector is detected. Since the effect of the dark current 12 can be removed, noise can be reduced and highly sensitive detection can be performed.

When the optical axis adjustment is carried out as described above, it can be carried out without using X-rays, so that the operator is not exposed to X-rays, and the X-ray irradiation position on the sample can be visually observed. I can confirm. In particular, in the case of a sample having unevenness on the surface, it can be surely confirmed whether or not the target portion is actually irradiated with X-rays.

[0025]

1 is a system configuration block diagram of an embodiment in which the method of the present invention is applied to an X-ray diffractometer.

FIG. 4 is a diagram showing the relationship between the intensity of scattered light, the sample tilt angle, and the vertical movement of the X-ray detector in this embodiment.

As shown in FIG. 1, He is used as the visible light source 3.
-Ne laser (100 mW) is used and geometrically, the angle between the laser beam axis and the optical axis of the X-ray detector 2 is 10.0 ° with respect to the center of the sample (center of the goniometer). (Integrated) Installed.

Further, the scattered light in the X-ray source when the laser beam is incident back to the X-ray source 6 is detected by the photodiode 12. As the sample 4, a quartz plate with gold vapor deposition was used.

The optical axis adjustment was performed by the following series of operations.

First, the sample 4 is irradiated with a laser beam,
An approximate arrangement is taken so that it reflects and goes toward the X-ray source 6. At this time, the incident angle and the extraction angle are fixed at α (reflection position, actually used angle is α = 30 °) so that the laser beam reflected on the sample surface can be detected most strongly.

After that, the drive device 13 for adjusting the tilt angle of the sample 4 is rotated, and the position where the scattered laser beam is detected most strongly by the photodetector 12 is searched for. Then, the sample tilt angle is fixed at the position where the scattered light is detected most strongly (in this embodiment, as shown in FIG. 4A, "tilt angle" = 1 °).

Similarly, the X-ray detector 2 and the vertical movement adjusting drive device 14 for the visible light source 3 are moved to search for a position where the scattered light intensity is maximum. The X-ray detector 2 is fixed at a position where the intensity of scattered light of the laser beam is maximized (in the case of this embodiment, "detector vertical movement" = 0 as shown in FIG. 4 (b)).
mm).

Next, the goniometer axis driving device 15 rotates only the rotation axis of the sample 4 (θ axis, where θ is the angle of incidence of X-rays on the sample), and similarly the angle at which the intensity of scattered light becomes maximum. Find and fix. In this example, the angle at this time was θ = 30 °.

Finally, the rotation axis of the X-ray detector 2 of the goniometer axis drive unit 15 (2θ axis, where 2θ is the angle between the direction of incident X-rays on the sample and the direction from the sample to the X-ray detector). Just rotate and search for the angle γ that maximizes the scattered light intensity. As described above, since there is a difference angle (10.0 °) between the X-ray detector 2 and the laser light source 3, it is 1 rather than γ.
An angle larger by 0.0 ° is 2θ = 70 ° in this embodiment.

By the above operation, the initial values of θ and 2θ (30 ° and 70 ° in this embodiment, respectively) are determined, and the X-ray optical axis adjustment is completed for the time being. In this embodiment, these series of operations are performed by the control command of the control calculator (computer) 16.

In order to improve the positioning accuracy of the goniometer shafts described above, a better result can be obtained by setting α to a different angle and performing the operations 1 to 3 again to converge the positions of the respective axes. .

Further, since the difference angle (10.0 °) between the X-ray detector 2 and the laser light source 3 is a geometrical arrangement, when the accuracy of the arrangement is a problem, the actual X-ray diffraction is used. Before the measurement, it is desirable to calibrate the initial value of the 2θ axis by using a single crystal sample cut out on a specific crystal lattice plane.
The calibration in this case can be performed only by actually generating X-rays, fixing the θ axis in accordance with the intervals of the cut lattice planes, and scanning only the 2θ axis in the same manner as above.

[0038]

According to the present invention, it is possible to accurately adjust the X-ray optical axis and confirm the X-ray irradiation position.

Since the method of the present invention can be carried out without using X-rays, the safety of workers can be secured.

[Brief description of the drawings]

FIG. 1 is a system configuration block diagram of an embodiment in which the method of the present invention is applied to an X-ray diffractometer.

FIG. 2 is a schematic diagram illustrating the relationship between a visible light source, a sample, an X-ray source, and an optical axis plane in the method of the present invention.

FIG. 3 is a vertical sectional view of an X-ray source showing a mechanism for detecting visible light scattered inside the X-ray source for carrying out the method of the present invention.

FIG. 4 is a diagram showing the relationship between the intensity of scattered light, the sample tilt angle, and the vertical movement of the X-ray detector.

[Explanation of symbols]

 1 Optical axis plane 2 X-ray detector 3 Visible light source 4 Sample surface (sample) 5 Visible light ray 6 X-ray source 7 and 8 X-ray emission slit 9 X-ray target material 10 Window material 11 Scattered visible light ray (scattered visible light ray) ) 12 photodetector 13 sample tilting drive device 14 detector vertical movement drive device 15 goniometer axis drive device (θ axis and 2θ axis) 16 control calculator 17 photodetection controller.

Claims (2)

[Claims] 1. Visible light is incident back toward an X-ray source and the visible light scattered by an X-ray transmitting substance or an X-ray target on the X-ray optical axis is detected, and the detected intensity of this scattered visible light is An X-ray optical axis adjusting method characterized by adjusting the position of a sample or the position of an X-ray detector so as to be the strongest. 2. A visible light source for making an X-ray source incident backwards,
A photodetector for detecting visible light scattered by an X-ray transmitting substance or an X-ray target on the X-ray optical axis, and a sample position or X-ray so that the detected intensity of the scattered visible light becomes the strongest.
An X-ray optical axis adjusting device, comprising: a movable means for adjusting the position of the ray detector.