JP3412936B2 - θ-θ scan type X-ray device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray apparatus for irradiating a sample with X-rays and detecting X-rays reflected, diffracted or scattered by the sample to determine the characteristics of the sample. In particular, the present invention relates to an X-ray device of a type in which both an X-ray source and an X-ray counter are rotationally moved with respect to a sample.

[0002]

2. Description of the Related Art An analysis method of determining the characteristics of a sample by using X-ray is widely used in various fields. The X-ray device used in this analysis method has X
There are various types such as a line camera device, a θ-2θ scan type X-ray device, a θ-θ scan type X-ray device and the like. Here, the X-ray camera device corresponds to, for example, the characteristics of the sample on the X-ray film by irradiating the fixedly arranged sample with X-rays and exposing the X-ray film with the X-rays diffracted by the sample. This is an apparatus for obtaining an X-ray diffraction image.

Further, the θ-2θ scan X-ray apparatus is, for example, that the sample is rotated continuously or intermittently at a constant angular velocity (so-called θ rotation), and at the same time, the X-ray counter is used as the center of the sample. While rotating in the same direction as θ rotation (so-called 2θ rotation) at an angular velocity twice that of θ rotation,
This is an apparatus for irradiating a sample with X-rays and detecting X-rays reflected, diffracted or scattered by the sample by an X-ray counter to calculate the X-ray intensity. This θ-2θ scan type X
In the X-ray device, the X-ray source is usually fixed and fixed in position.

Further, the θ-θ scan type X-ray apparatus is, for example, a sample in which the sample is fixedly fixed and the X-ray source is continuously or intermittently rotated around the sample at a constant angular velocity (so-called, X-ray source θ rotation) and simultaneously rotate the X-ray counter in the opposite direction at an angular velocity equal to θ rotation of the X-ray source (so-called counter θ rotation) while irradiating the sample with X-rays emitted from the X-ray source. The X-ray intensity is calculated by detecting an X-ray reflected, diffracted or scattered by the sample by an X-ray counter. This θ-θ scan X-ray apparatus does not require the sample to be rotated by θ, and is therefore suitable when a sample that cannot be moved, such as a liquid, is the measurement target.

Of the various X-ray apparatuses described above,
X-ray scan X-ray device
Consider the case where a linear reflectance measurement is performed. This X-ray reflectance measurement means that a sample is irradiated with X-rays from a low angle, and the X-rays reflected by the sample are detected by an X-ray counter to reflect X-rays.
This is a measuring method adapted to measure the intensity of a line. The low angle mentioned here is usually an angle range in which the reflection angle (θ) with respect to the sample surface is 1 ° or less. In this X-ray reflectance measurement, an X-ray intensity change curve K as shown in FIG. 7, for example, is obtained as the measurement result. For example, by measuring the length of the cycle T appearing on the change curve K, the thickness of the oil film formed on the surface of the water as the liquid sample can be determined.

[0006]

However, θ-θ
In the conventional X-ray reflectance measurement performed by using the scanning X-ray device, vibrations caused by the θ rotation of the sample and the θ rotation of the X-ray counter are transmitted to the liquid sample, and the surface of the liquid sample becomes wavy. However, there is a problem that it appears as a jagged vibration waveform on the X-ray intensity change curve K, and as a result, the measurement accuracy decreases. When an intense X-ray is to be generated from an X-ray source, a rotating rotor target is often used as an anticathode. In this case, vibration caused by the rotation of the rotor target causes liquid sample to rotate. Communicate,
It is conceivable that the accuracy measurement will be further reduced.

The present invention has been made in order to solve the above problems, and reduces the vibration transmitted to the sample,
In particular, it is an object of the present invention to enable highly accurate X-ray reflectance measurement for a liquid sample.

[0008]

In order to achieve the above-mentioned object, an X-ray apparatus according to the present invention comprises a sample support table on which a sample is placed, and an X-ray source which rotates and moves around the sample on the sample support table. , Rotating around the sample on the sample support X
In a θ-θ scan X-ray apparatus having a line counter, a gonio frame that supports an X-ray source and an X-ray counter and a sample support table that supports a sample are separately and independently installed on the floor. . Although the gonio frame and the sample support can be installed directly on the floor, it is desirable that at least one of the gonio frame and the floor and / or the sample support and the floor is made of ceramic composite material or the like. A vibration damping member is interposed. As the ceramic-based composite material, for example, a material obtained by baking aluminum to harden, concrete, or the like can be considered.

The floor on which the gonio frame and the sample support stand are not required to be specially designed, but it is desirable to provide a groove in the floor so as to surround the sample support stand. By doing so, the transmission of vibration to the sample can be further reduced. Further, by filling the groove with sand, gravel, crushed stone, or a mixture thereof, vibration transmission can be further reduced.

The present invention is particularly advantageous when it is applied to X-ray reflectance measurement in which a liquid sample is the object of measurement. In X-ray reflectance measurement with a liquid sample as a measurement target, the liquid sample is supported on a sample support table, and further, the X-ray emitted from the X-ray source is used.
The line enters the liquid sample from a low angle direction with respect to the liquid surface of the liquid sample, for example, an angle direction in which the reflection angle 2θ is smaller than about 2 °.

[0011]

In the θ-θ scan X-ray apparatus according to the present invention,
The X-ray source rotates θ around the sample, and at the same time, the X-ray counter rotates θ around the sample in the direction opposite to the X-ray source. Thus, while both the X-ray source and the X-ray counter rotate in the opposite directions by θ, the X-rays emitted from the X-ray source are incident on the sample, and the X-rays reflected, diffracted or scattered by the sample are X-rays. Counted by line counter. Since the sample support table that supports the sample is installed on the floor separately and independently from the gonio frame that supports the X-ray source and the X-ray counter, it vibrates due to the θ rotation of the X-ray source and the X-ray counter. Even if the vibration occurs, the vibration is hardly transmitted to the sample.
Therefore, it becomes possible to perform measurement with higher accuracy than a conventional method for a sample such as a liquid sample that is not susceptible to vibration.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a θ-θ scan X-ray apparatus according to the present invention. This X-ray device includes a gonio frame 5 placed on a floor 11 by two supporting legs 10, and an X-ray source mounted on the front side surface of the gonio frame 5 and rotatable about a sample axis ω. It has an arm 2 and a counter arm 4 which is also attached to the side surface of the gonio frame 5 and is rotatable about the sample axis ω. The sample axis ω means that the gonio frame 5 is aligned with the surface of the sample to be measured.
Is an axis line that is virtually set on the side surface of the.

On the side surface of the X-ray source arm 2, an X-ray tube 1 containing an X-ray source S and an incident optical unit 8 are provided.
The incident optical unit 8 accommodates an X-ray divergence limiting slit that limits divergence of X-rays emitted from the X-ray source S, a monochromator that is provided as necessary, and the like.
On the other hand, the X-ray counter 3 and the light receiving optical unit 30 are provided on the side surface of the counter arm 4. In the light receiving optical unit 30, unnecessary scattered X-rays are generated by the X-ray counter 3
A light-receiving slit 9 for preventing entry and a monochromator provided as necessary are accommodated. The X-ray counter 3 detects the captured X-ray and outputs it as an electric signal, and the output signal is sent to the measurement calculation section 19. The measurement calculation unit 19 calculates the X-ray intensity based on the transmitted signal. The calculation result is hard-copied by the printer 20 or displayed as an image on the CRT 21.

The X-ray source S is, for example, as shown in FIG. 2, a target 15 that rotates at a high speed around a rotation axis L1.
And a filament 16 arranged to face the target. The thermoelectrons generated from the filament 16 due to the energization collide with the focus area F of the target 15 at a high speed, so that X-rays are generated from the focus area F.

Returning to FIG. 1, the X-ray source arm 2 is driven by the θ _s rotation driving device 6 to rotate about the sample axis ω. The counter arm 4 is driven by the θ _d rotation driving device 7 and rotates about the sample axis ω. The θ _s rotation driving device 6 and the θ _d rotation driving device 7 are
For example, it is constituted by a worm wheel connected to the center axes of rotation of the arms 2 and 4, and a worm that meshes with the worm wheel and is driven by a pulse motor or other motor to rotate.

On the front side of the gonio frame 5, a support leg 12 is provided independently of the support legs 10 and 10 for the gonio frame.
Is installed, a sample support base 13 is provided on the support leg 12, a sample container 14 is placed on the sample support base 13, and a liquid sample S _a to be measured is placed in the sample container 14. Is housed. As shown in FIG. 3, the liquid sample S _a is slightly ejected from the sample container 14 due to the influence of the surface tension. The sample support base 13 is driven by a sample elevating / lowering drive device 17 so that it can be moved up and down in the vertical direction in the figure. The sample elevating / lowering drive device 17 is composed of, for example, a linear rack integrated with the sample support base 13, and a gear that meshes with the linear rack and is driven by a pulse motor to rotate.

Θ _s rotation drive device 6, θ _d rotation drive device 7
The operation of the sample elevating and lowering drive device 17 is controlled by the gonio control unit 18.

The operation of the θ-θ scan type X-ray apparatus having the above structure will be described below. First, the sample container 14 is moved up and down by the sample elevating and lowering drive device 17 to accurately align the surface of the liquid sample S _a with the sample axis ω. Further, the rotation angle θ _s of the X-ray source arm 2 is set to θ _s = 0 °, and the rotation angle θ _d of the counter arm 4 is set to θ _d = 0 °. Thereby, the X-ray source arm 2
And the counter arm 4 is set at an angle of 180 °, that is, in a straight line state.

Thereafter, the X _s rotation driving device 6 intermittently or continuously rotates the X-ray source arm 2 in the counterclockwise direction (so-called θ _s rotation), and at the same time, the θ _d rotation driving device 7 intermittently rotates the counter arm 4. To rotate in a counterclockwise direction (so-called θ _d rotation). The rotation of the arms 2 and 4 at this time is performed in a state where θ _s = θ _d is accurately maintained. While the X-ray source S rotates by θ _{s and} at the same time the X-ray counter 3 rotates by θ _d , the X-rays emitted from the X-ray source S enter the liquid sample S _a from a low angle direction. The low angle mentioned here is an angle at which the X-rays incident on the liquid sample S _a can be totally reflected on the surface thereof, and specifically, in FIG. 3, the X-ray reflection angle 2θ is It is an angle within a narrow angle range of about 2 ° or less.

The X-rays incident on the sample S _a at _a low angle are reflected on the surface of the sample S _a , the reflected X-rays are counted by the X-ray counter 3, and the intensity of the reflected X-rays is further measured by the measurement calculation unit 19. Is calculated. As a result of this calculation, a change in the reflected X-ray intensity with respect to each X-ray reflection angle (2θ) is displayed as a graph as shown in FIG. 7, for example.
From this graph, various characteristics relating to the liquid sample S _a , such as the film thickness of the surface layer, are determined. By the way, X in this embodiment
In the X-ray apparatus, the rotor target 15 in the X-ray tube 1
Vibrations occur in the gonio frame 5 due to the high speed rotation (FIG. 2), the θ _s rotation of the X-ray source arm 2, the θ _d rotation of the counter arm 4, and the like. However, in this embodiment, since the supporting leg 12 for the sample is installed on the floor 11 separately from the supporting leg 10 for the gonio frame, the vibration of the gonio frame 5 is almost transmitted to the liquid sample S _a. As _{a result} , the surface of the liquid sample S _a is hardly wavy. Therefore, highly reliable reflectance measurement can be performed.

FIG. 4 shows a θ-θ scan type X according to the present invention.
The 2nd example of a line device is shown. This embodiment is different from the X-ray apparatus shown in FIG. 1 in that concrete 22 is used as a vibration damping member between the support leg 10 for the gonio frame and the floor 11 and between the support leg 12 for the sample and the floor 11. It was intervening. Due to the presence of this concrete, sample S
transmission of vibration to _a is further reduced. As the vibration damping member, a ceramic-based composite material other than concrete, for example, a material obtained by baking aluminum to be solidified, or the like, and various materials other than the ceramic-based composite material capable of reducing vibration can be used. You can also

FIG. 5 shows a θ-θ scan type X according to the present invention.
The 3rd example of the line device is shown. This embodiment is different from the X-ray apparatus shown in FIG. 1 in that the sample support base is provided in the floor 11 between the support leg 12 on which the sample support base 13 is mounted and the support leg 10 on which the goniometer frame 5 is mounted. The annular groove 23 is provided so as to surround the support leg 12 of FIG. This annular groove 2
The presence of 3 further reduces the transmission of vibrations to the sample S _a . Note that the groove 23 does not necessarily have to be formed in an annular shape. For example, four grooves can be provided in a discontinuous state at four corners surrounding the support leg 12.

FIG. 6 is a modification of the embodiment shown in FIG. Specifically, the inside of the annular groove 23 is filled with sand, gravel, crushed stone, or a mixture 24 thereof. The presence of the sand or the like further reduces the transmission of vibration to the sample S _a .

Although the present invention has been described above with reference to the preferred embodiments, the present invention is not limited to these embodiments and can be variously modified within the technical scope described in the claims.

[0025]

According to the θ-θ scan type X-ray apparatus of the first aspect, the gonio frame for supporting the X-ray source and the X-ray counter and the sample support stand for mounting the sample are separately installed on the floor. Therefore, during the X-ray measurement, the vibration transmitted to the sample is reduced and the sample is stably held, so that an extremely stable and highly reproducible measurement result can be obtained. In particular,
The reliability and reproducibility of the measurement results are remarkably improved when the X-ray reflectance measurement is performed on a liquid such as a liquid that is easily affected by vibration, that is, when the sample is irradiated with X-rays from a low angle direction. To do.

According to the θ-θ scan X-ray apparatus of the second to fifth aspects, the vibration transmitted from the goniometer to the sample can be further reduced.

[0027]

[Brief description of drawings]

FIG. 1 is a diagram showing both a mechanical configuration and an electrical control system of an embodiment of a θ-θ scan X-ray apparatus according to the present invention.

FIG. 2 is a perspective view showing an example of an X-ray source used in the X-ray apparatus shown in FIG.

FIG. 3 is an enlarged view showing a main part of the X-ray apparatus shown in FIG.

FIG. 4 is a second θ-θ scan X-ray apparatus according to the present invention.
It is a front view showing an example.

FIG. 5 is a third θ-θ scan X-ray apparatus according to the present invention.
It is a front view showing an example.

FIG. 6 is a fourth θ-θ scan X-ray apparatus according to the present invention.
It is a front view showing an example.

FIG. 7 is a graph showing a measurement result by the X-ray apparatus shown in FIG. 1, particularly a result of X-ray reflectance measurement regarding a liquid sample.

[Explanation of symbols]

1 X-ray tube 2 X-ray source arm 3 X-ray counter 4 counter arm 5 Gonio frame 8 Incident optical unit 9 Light receiving slit 10 Gonio frame support legs 11 floors 12 Sample support legs 13 Sample support 14 Sample container 22 Concrete (vibration damping member) 23 annular groove 24 Sand, gravel, crushed stone or mixtures thereof

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 23/207

Claims (6)

(57) [Claims] 1. A θ-having a sample support table on which a sample is placed, an X-ray source that rotates and moves around the sample on the sample support table, and an X-ray counter that rotates and moves around the sample on the sample support table. In the θ scan X-ray device, a gonio frame supporting an X-ray source and an X-ray counter,
A θ-θ scan type X-ray apparatus, characterized in that the sample support table is separately and independently installed on the floor. 2. The θ-θ scan X-ray apparatus according to claim 1, wherein a vibration damping member is interposed between at least one of the floor and the gonio frame and between the floor and the sample support. The θ-θ scan type X-ray device. 3. The θ-θ scan X-ray device according to claim 2, wherein the vibration damping member is a ceramic composite material. 4. The θ-θ scan X-ray apparatus according to claim 1, wherein a groove is provided in the floor so as to surround the sample support base. 5. The θ-θ scan X-ray device according to claim 4, wherein the groove is filled with sand, gravel, crushed stone, or a mixture thereof. 6. The θ-θ scan type X-ray apparatus according to claim 1, wherein a liquid sample is supported on a sample support table, and X-rays emitted from an X-ray source are applied to the liquid sample. The θ-θ scan type X-ray device which is also incident from a low angle direction on the liquid surface.