JPH09178676A - X-ray collimator and x-ray radiation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an X-ray collimator in which X-rays of high intensity can be taken out while the parallelism of the X-rays is being kept to be high by a method wherein a plurality of thin tubes comprising a tube wall part which does not transmit the X-rays are provided and a holding body which bundles and holds the thin tubes in a parallel state is provided. SOLUTION: A light-emitting device 22 emits light toward the inside of a collimator body 20. By a semitransparent mirror 24, the light which is emitted from the light-emitting device 22 advances through every thin tube 30. The semi-transparent mirror 24 does not obstruct the advance of X-rays passing inside the collimator body 20. X-rays which are incident on a collimator 10 advance through every thin tube 30. The X-rays advance inside every thin tube 30 without being transmitted through its tube wall part. In the collimator 10, the intensity of the X-rays is extremely strong as compared with a collimator in conventional cases when a collimator diameter and also a divergent angle are identical. That is to say, while the parallelism of the X-rays is being kept to be high, the intensity of the X-rays can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to X-rays which take out only parallel X-rays from X-rays traveling in various directions.
It relates to a line collimator.

[0002]

BACKGROUND OF THE INVENTION To analyze the properties of solid materials, X
Line diffraction may be used. The following devices are available for this purpose. As shown in FIGS. 6 and 7,
The apparatus includes an X-ray generator 100 and a goniometer 11
0 and the sensor 120. The sensor 120 is connected to the computer 130.

In the X-ray generator 100, a target 102 made of molybdenum or the like is irradiated with an electron beam from an electron beam irradiator 104, and the target 102 is
X-rays are emitted from each direction. The X-ray generator 100 is provided with a collimator 150, and the X-ray generator 1
Of the X-rays emitted from 00 (target 102),
Only parallel X-rays are emitted to the outside. Further, a slit 160 (may be a collimator) is also provided on the front side of the sensor 120 so that only parallel X-rays can be taken into the sensor 120. The object to be measured W is placed on the goniometer 110, and its posture can be variously changed.

The X-rays emitted from the X-ray generator 100 through the collimator 150 are incident on the object to be measured W (the X-rays are referred to as incident X-rays), and diffracted X-rays diffracted from the object to be measured W are generated. Received by sensor 120 via slit 160, which is analyzed by computer 130.

Both the incident X-rays and the X-rays of the diffracted X-rays that are taken into the sensor 120 must be parallel. For this purpose, as described above, the collimator 150
Alternatively, the slit 160 is provided.

[0006]

2. Description of the Related Art The following is a conventional collimator (150). That is, as shown in FIG. 8, the collimator 50 has at least two pinhole members 52 and 54 in the X-ray traveling direction.
Then, only the X-rays transmitted through both the pinhole members 52, 54 (the respective pinholes) are taken out.
The divergence angle α ₂ of the X-ray is expressed by the following equation. α ₂ = D ₂ / L ₂ (radian) = 360 D ₂ / (2πL ₂ ) (°) Note that D ₂ is the diameter of the pinhole and L ₂ is the distance between the two pinhole members 52 and 54. . Further, hereinafter, for convenience, D ₂ is also referred to as a collimator diameter, and L ₂ is also referred to as a collimator length. The smaller the value of this divergence angle α ₂ , the higher the parallelism.

By the way, in the above-mentioned analysis using X-ray diffraction, it is preferable that the X-rays are substantially parallel and the intensity of the X-rays is strong. Since the intensity of X-rays traveling radially is attenuated in inverse proportion to the square of the distance, from the point of view of the intensity of X-rays, X-ray diffraction can be performed within a range where the traveling distance of X-rays is short. desirable.

However, the conventional collimator 50 described above is used.
When the collimator length L ₂ is shortened, the intensity of X-rays (the intensity of X-rays traveling through the collimator 50) becomes stronger,
The divergence angle α ₂ increases and the parallelism of X-rays decreases. Further, if the collimator length L ₂ is shortened and the collimator diameter D ₂ is reduced, the parallelism of X-rays is maintained, but the intensity of incident X-rays originally decreases,
X-ray intensity becomes low. In this way, the intensity of X-rays and the parallelism have a contradictory relationship.

Since X-rays have a low refractive index, it is difficult to focus them by a lens and make them parallel to each other.
Since lines are difficult to be reflected, it is difficult to make them parallel by reflecting them on a reflecting surface.

Further, in the X-ray generator 100 as described above, the energy (intensity) of the X-rays generated out of the energy of the electron beam with which the electron beam irradiator 104 irradiates the target 102 is as low as 1% or less. And that weak X
Lines are radiated from the target 102 in multiple directions. For this reason, since the intensity of the parallel (nearly parallel) X-rays extracted from the X-rays emitted from the X-ray generator (target 102) is very weak, it is desired to minimize the attenuation due to the distance. There is a request.

Therefore, it is an object of the present invention to provide an X-ray collimator capable of extracting highly intense X-rays while keeping the parallelism of the X-rays high.

[0012]

In order to solve this problem, the invention according to claim 1 is an X-ray collimator for extracting only substantially parallel X-rays from X-rays traveling in various directions. It is characterized in that it has a plurality of thin tubes having a tube wall portion that does not transmit X-rays, and a holding body that holds the plurality of thin tubes in a bundle in a parallel state. Here, the “narrow tube” is not limited to a cylindrical tube, but includes a polygonal tube such as a square tube or a hexagonal tube. Further, the material is not limited to a hollow material, but may be filled with a substance that can transmit X-rays.

According to the present invention, parallel X-rays are extracted from each thin tube as in the conventional collimator. Therefore, in order to increase the parallelism of the X-rays, it is sufficient to make each thin tube thin (correctly, the cross-sectional area of the passage is small), and by shortening the length of each thin tube accordingly, X in each thin tube is reduced.
The strength of the line can be maintained (the decrease in strength can be reduced). Further, the reduction in the intensity of the incident X-rays due to the thinning of each thin tube (thus reducing the intensity of the X-rays extracted) can be compensated by increasing the number of thin tubes bundled. in this way,
In the present invention, both the parallelism and the intensity of X-ray can be increased.

The invention according to claim 2 is the invention according to claim 1, wherein the tube wall portion of the thin tube does not transmit light, and a light emitting portion provided near the thin tube,
Provided on the upstream side of the thin tube to reflect the light from the light emitting unit so that the reflected light travels in the thin tube, while allowing the X-rays from the X-ray source to travel,
And a half mirror that reflects the light emitted from the light emitting unit and guides the reflected light to the thin tube. Here, as the “light emitting portion”, various things such as light emission by a light emitting diode and light emission by a laser are applied.
Further, the light itself is not limited to the one that emits light, and the light emitted in other places is also guided by an optical fiber to emit the light.

According to the present invention, the light emitted from the light-emitting device is reflected while the X-rays are allowed to travel by the half mirror, and the reflected light passes through the thin tube and, like the X-rays,
Only parallel light is extracted. Then, the light is in the same direction as the X-ray. Therefore, the arrival position (aim) of the X-ray can be easily recognized by confirming the arrival position of the light, which is convenient for adjusting the direction and the like of the collimator.

The invention according to claim 3 is the invention according to claim 1, wherein the tube wall portion of the thin tube does not transmit light, and a light receiver provided in the vicinity of the thin tube,
It is provided on the upstream side of the plurality of thin tubes, allows the X-rays to travel, and reflects the light traveling in the thin tubes in a direction opposite to the traveling direction of the X-rays to the light receiver. And a half mirror that guides. In addition,
A camera or the like corresponds to the “light receiver”.

According to the present invention, the light from the arrival position of the X-ray (reflected light from an interior lamp or the like) travels in the thin tube in the direction opposite to the X-ray traveling direction, is reflected by the half mirror, and is received by the light receiver. Received light. As in the second aspect of the invention, the half mirror does not hinder the progress of X-rays. Therefore, it is possible to easily recognize the arrival position (aim) of the X-ray by recognizing the light received by the light receiver (the generation position of the reflected light), and the same effect as that of the invention of claim 2 is obtained. Can be obtained.

Further, the invention according to claim 4 is the X-ray tube which radiates X-rays from the X-ray extraction window, and the tube wall portion which is provided in front of the X-ray extraction window and which does not transmit X-rays and light. Has a collimator configured by bundling a plurality of thin tubes in a parallel state, and a light emitting portion provided in the vicinity of the collimator, and the light from the light emitting portion emits X-rays of the X-ray tube. The window is irradiated, and the reflected light is guided to the collimator. In the inventions according to claims 1 to 4 described above, the fact that the tube wall portion of the thin tube does not transmit X-rays or light is not limited to the one that does not transmit at all, and compared with the amount that advances inside the thin tube. The amount of light that penetrates through the tube wall is considerably small.

In the present invention, the X-rays generated inside the X-ray tube are radiated from the X-ray extraction window, the X-rays pass through the collimator, and the X-rays are almost parallel to each other, as in the invention of claim 1. Only lines are taken out. Further, the light from the light emitting portion is irradiated to the X-ray extraction window of the X-ray tube, and the reflected light passes through the collimator, and the X-ray extraction window is provided with the X-ray extraction window.
Only parallel light that is the same as the line is extracted. Therefore, the arrival position (aim) of the X-ray can be easily recognized by confirming the arrival position of the light, which is convenient for adjusting the direction and the like of the collimator. Further, in the present invention, since the light is reflected by using the X-ray extraction window of the X-ray tube, it is not necessary to separately provide a member for reflecting the light, and the device can be made compact. In the present invention, it is desirable that the X-ray extraction window be processed (a thin film of aluminum or the like) to make it easier to reflect the light from the source. Further, it is desirable to have a curved surface so that the reflected light is concentrated on the thin tube.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> Next, a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the X-ray collimator 10 has a collimator body 20 (holding body) and a large number of thin tubes 30. The collimator body 20 has a cylindrical shape. The tip is slightly squeezed. The minimum inner diameter will be referred to as the collimator diameter D ₁ . As shown in FIG. 2, each thin tube 30 has a thin circular tube shape having the same structure. The total length is L ₁ , the outer diameter is do, and the inner diameter is
It will be displayed as di. In addition, for convenience, this thin tube 3
The length L ₁ of 0 is also referred to as a collimator length.

Each thin tube 30 (tube wall portion thereof) is made of a material that does not transmit X-rays. For example, lead glass (glass containing 50% lead) and the like. In addition, this tube wall portion does not transmit light. The inside of each thin tube 30 is hollow, and X-rays can pass through the inside thereof. It can also transmit light. Then, the thin tubes 30 are bundled in a parallel state, filled and held inside the collimator body 20.

At one side of the collimator body 20 upstream of the thin tube 30 (opposite to the X-ray traveling direction),
A light emitter 22 is provided. The light emitter 22 emits light toward the inside of the collimator body 20. Further, inside the collimator body 20, a half mirror 24 is provided corresponding to the light emitter 22 (that is, on the upstream side of the thin tube 30). The half mirror 24 allows the light emitted from the light emitter 22 to travel through each thin tube 30 (inside). The half mirror 24 does not hinder the progress of X-rays passing through the inside of the collimator body 20.

Next, the function and effect of the X-ray collimator 10 will be described. The X-ray incident on the collimator 10 is
It advances through each thin tube 30 (passage inside it). The X-rays propagate in each thin tube 30 without penetrating the tube wall. That is, as indicated by the solid line, X-rays that do not hit the tube wall of the thin tube 30 go straight. As shown by the broken line, when the incident angle θ of the thin tube 30 with respect to the tube wall portion is small, it is reflected by the tube wall portion. Further, as shown by the chain double-dashed line, when the incident angle θ is larger than a certain value, it is absorbed by the tube wall portion of the thin tube 30.

Divergence angle α of X-ray emitted from each thin tube 30
₁₁ is represented by the following equation (see FIG. 2). α ₁₁ = di / L ₁ (radian) = 360di / (2πL ₁ ) (°) Then, the divergence angle α ₁ of the X-ray emitted from the collimator 10 can be calculated by the following formula: α ₁₁
And the same value (see FIG. 1). α ₁ = α ₁₁ = di / L ₁ (radian) = 360di / (2πL ₁ ) (°)

On the other hand, as a collimator diameter D ₂ of the collimator diameter D ₁ and a conventional collimator 50 of the collimator 10 is the same, cross-sectional area S of the X-ray collimator 10
The ratio of ₁ (total of each thin tube 30) and the passage cross-sectional area S ₂ of the conventional collimator 50 is obtained. S ₁ : S ₂ = (di / do) ² · f + (1-f): 1 Here, f is the filling degree when the thin tube 30 is filled inside the collimator body 20. (1-f)
Indicates a gap between the thin tubes 30. This is because the X-rays propagate in the gaps between the thin tubes 30 as in the inside of the thin tubes 30. f
Is as follows by calculating inside the two-dot chain line triangle in FIG. in ^{f = (3 × (πdo 2} /4) / 6) / ((do / 2) · (3 1/2 · do / 2)) = π / (2 · 3 1/2) Further, each capillary 30 It is assumed that the ratio of the outer diameter do and the inner diameter di is as follows. When do: di≈1.5: 1, the ratio of the cross-sectional areas S ₁ and S ₂ of both passages is as follows. S ₁ : S ₂ = 1: 2

Here, there is the following relationship between the intensity P of the X-ray, the passage cross-sectional area S and the distance M. P∝S / (M ² ) The X-ray intensity P is the X-ray intensity at the tip of the collimator 10, and the distance M is the distance from the target 102 to the tip of the collimator 10. Yes (see Figure 2). Also, the intensity P of the X-ray, in the case of the collimator 10 P _1, in the case of the conventional collimator 50 corresponds is P _2. Similarly, the passage cross-sectional area S corresponds to S ₁ and S ₂ , and the distance M corresponds to M ₁ and M 2.
Display as ₂ . Then, the collimator length L of this distance M (in the case of this collimator 10, as described above, the thin tube 3
The length L ₁ is 0, and in the case of the conventional collimator 50, the length L ₂ between the pinhole members 52 and 54 is as described above.
It is. It is assumed that the lengths of the portions other than () are the same in both the collimator 10 and the conventional collimator 50. Let its length be N.

Therefore, when the divergence angles α ₁ and α ₂ are the same, the ratio of the intensity P of the X-ray (the ratio of the intensity P ₁ of the collimator 10 to the intensity P ₂ of the conventional collimator 50).
Is as follows: P ₁ : P ₂ = S ₁ / (M ₁ ² ): S ₂ / (M ₂ ² ) = 1 / (L ₁ + N) ² : 2 / (L ₂ + N) ² = (L ₂ + N) ² : 2 (L ₁ + N) ² Here, the collimator diameter D ₂ of the conventional collimator 50 =
When 1.7 mm and collimator length L ₂ = 220 mm, the divergence angle α ₂ is as follows. α ₂ = 360 D ₂ / (2πL ₂ ) = 0.44 (°)

In the collimator 10, the collimator length L ₁ when the inner diameter of each thin tube 30 is di = 0.1 mm and the same divergence angle α ₁ = α ₂ as described above is obtained, is as follows. L ₁ = 360di / (2πα ₁ ) = 13 (mm)

If both N = 20 (mm),
The ratio of intensity P is as follows. _{P 1: P 2 = (L} 2 + N) 2: 2 (L 1 + N) 2 = 57600: 2178 = 26.5: 1

As described above, the collimator 10 has an X-ray intensity that is 26.5 times stronger than that of the conventional collimator 50 when the collimator diameter is the same and the divergence angle is the same. That is, the intensity of the X-ray can be increased while keeping the parallelism of the X-ray high.

Before performing X-ray diffraction using this collimator 10, the orientation of the collimator 10 can be adjusted as follows. That is, when light is emitted from the light emitter 22, the light is reflected by the half mirror 24 and travels through each thin tube 30. The traveling direction is the same as the X-ray. For this reason, the arrival position of the X-ray (aim) is confirmed by confirming the position where the light hits (object to be measured W).
Can be easily recognized in advance. As a result, the collimator 1 is set so that the X-rays reach the appropriate position.
The orientation of 0 can be adjusted. Of course, it can be used to confirm the arrival position of the X-ray after the fact.

Further, instead of the light emitter 22, the camera 2
When 6 is provided, the half mirror 24 reflects the reflected light traveling from the arrival position of the X-ray in the direction opposite to the traveling direction of the X-ray, and the reflected light is captured by the camera.
In this way, the arrival position of the X-ray can be recognized in advance, and the orientation of the collimator 10 can be adjusted based on it.

The collimator 10 can be used not only as the collimator 150 in FIG. 6 but also as the slit 160. That is, the incident X-rays are not limited to parallel ones, and the parallel X-rays can be used out of the diffracted X-rays.

<Second Embodiment> Next, an X-ray emitting apparatus 200 according to a second embodiment of the present invention will be described with reference to FIG. 5, focusing on the differences from the first embodiment. The X-ray emitting device 200 has an X-ray tube (X-ray generating device) 210, a shield box 220, and a collimator 310.
The collimator 310 has the same structure as the collimator 10 of the first embodiment, and has a cylindrical collimator body 32.
0, and the thin tubes 330 are bundled and filled inside. Collimator 310 is shield box 220
Is attached to the mounting hole 222. An X-ray tube 210 is housed in the shield box 220. In the vicinity of the mounting hole 222 of the shield box 220, a plurality of light emitters 224 (light emitting parts) such as light emitting diodes are provided in a circumferential shape so as to surround the collimator 310. It should be noted that, as virtually shown by a chain double-dashed line, light emitted at another place may be guided by the optical fiber 226.

The X-ray tube 210 has a substantially cylindrical shape, and an electron beam generator 212 and a target 214 are provided inside the X-ray tube 210. Also, on the side wall of the X-ray tube 210,
An X-ray extraction window 216 is provided. X-ray extraction window 2
Reference numeral 16 is made of a material (such as beryllium) that attenuates X-rays little, and has a concave shape that is recessed inward. X
On the surface of the line extraction window 216, aluminum (or magnesium, synthetic resin,
A thin film of ceramic or the like) is provided. Then, the target 214 is irradiated with an electron beam from the electron beam generator 212, the X-ray generated thereby is emitted from the X-ray extraction window 216, and the X-ray is emitted.
0 (each thin tube 330) is incident on the collimator 310 (each thin tube 330), and X-rays having high parallelism are emitted to the outside.

In this apparatus, in order to aim the X-ray, the following is done. That is, the light emitter 224
When the light is emitted from the light source, the light strikes the X-ray extraction window 216, is reflected, enters the collimator 310 (each thin tube 330), and the light in the same direction as the direction of the collimator 310 is emitted to the outside. Therefore, the arrival position of the X-ray can be confirmed by confirming the arrival position of the light. Then, based on this, the orientation of the collimator 310 can be adjusted.

[Brief description of the drawings]

FIG. 1 is a view showing an X-ray collimator of a first embodiment of the present invention, (a) is a sectional view taken along line AA in (b), and (b) is
It is a BB sectional view in (a).

FIG. 2 is a view showing one thin tube in the collimator of FIG. 1, (a) is a sectional view taken along line AA in (b), and (b) is a sectional view taken along line BB in (a). Is.

FIG. 3 is a diagram showing the progress of X-rays in the thin tube of FIG.

FIG. 4 is a partially enlarged view of FIG.

FIG. 5 is a sectional view showing an X-ray emitting device according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing an entire analyzer by X-ray diffraction.

FIG. 7 is a plan view of the device of FIG. 6;

FIG. 8 is a diagram showing a main part of a conventional X-ray collimator.

[Explanation of symbols]

 10,310 X-ray collimator 20,320 Collimator main body (holding body) 30,330 Capillary tube 22 Light emitter 24 Half mirror 26 Camera (light receiver)

Claims (4)

[Claims] 1. An X-ray collimator for extracting substantially parallel X-rays from X-rays traveling in various directions, the plurality of thin tubes having a tube wall portion that does not transmit X-rays, and the plurality of thin tubes. X-ray collimator, which has a holder for bundling and holding the thin tubes in parallel. 2. The X-ray collimator according to claim 1, wherein the tube wall portion of the thin tube does not transmit light, and a light emitting portion provided near the thin tube, and an upstream side of the thin tube. Is provided to reflect the light from the light emitting unit so that the reflected light travels in the narrow tube, while allowing the X-rays from the X-ray source to travel,
An X-ray collimator, comprising: a half mirror that reflects light emitted from the light emitting unit and guides the reflected light to the thin tube. 3. The X-ray collimator according to claim 1, wherein the tube wall portion of the thin tube does not transmit light, and a light receiver provided near the thin tube, and the plurality of thin tubes. And a half mirror that is provided on the upstream side of the half mirror, allows the X-rays to travel, and reflects the light traveling in the narrow tube in a direction opposite to the X-ray traveling direction to guide the light to the light receiver. An X-ray collimator having: 4. An X-ray tube that emits X-rays from an X-ray extraction window, and a plurality of thin tubes provided in front of the X-ray extraction window and having a tube wall that does not transmit X-rays and light are parallel. The collimator is configured to be bundled in a state, and a light emitting portion provided in the vicinity of the collimator. Light from the light emitting portion is irradiated to the X-ray extraction window of the X-ray tube, An X-ray emitting device, wherein reflected light is guided to the collimator.