JP2003149392A - X-ray intensifying reflecting plate and x-ray inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray intensifying reflecting plate and an X-ray inspection device capable of remarkably intensifying a signal amount of the X-ray inspection device using a linear detector. SOLUTION: An extremely flat metal plate is disposed as an X-ray reflecting plate so as to form a two-dimensional elliptic surface, an X-ray emitted from an X-ray source disposed at one focal position of the ellipse is totally reflected by the elliptic surface and linearly converged on the other focal position, and thus the intensity of the X-ray entered into the linear detector is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray inspection apparatus having a linear detector, and in particular, X-rays from an X-ray source are linearly focused by using a multilayer reflector to amplify the signal intensity. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, as an apparatus utilizing the total reflection of X-rays, an objective lens for an X-ray microscope, a lens for an X-ray astronomical telescope, etc., which has been mainly used for academic purposes, was devised, and its principle has been known. However, it was rarely applied to industrial equipment such as inspection equipment. Generally, X-rays used in medical and industrial inspection devices are produced by applying an electron beam to an anticathode, but since the X-ray generation efficiency is extremely low, X-ray tubes have been used conventionally. We have responded by improving the power of, improving the image intensifier (image intensifier), etc. As an X-ray intensifying device that intensifies X-rays until the X-rays from the X-ray source irradiate the object, a large number of micro hollow tubes are bundled and the X-rays are totally reflected on the inner surface. The present invention has only devised a device for focusing on a desired focus or line, and has not been put into practical use.

[0003]

As described above, X-rays used in medical and industrial inspection devices have extremely low X-ray generation efficiency, and in order to obtain the required X-ray intensity, an X-ray source is required. It was supported by powering up the side and improving the image intensifier. However, in the X-ray linear detector, even if such a measure is taken, the amount of X-rays incident on the linear detector in the X-ray flux emitted from the X-ray source is small, and considerable X-rays are generated. It was thrown away and wasted.

The present invention has been made under the circumstances as described above, and an object of the present invention is to enhance the X-ray intensity capable of significantly increasing the signal amount of the X-ray inspection apparatus using the linear detector. To provide a reflector and a device.

[0005]

The present invention relates to an X-ray intensifying reflector and an X-ray inspection apparatus for intensifying X-rays by using total internal reflection, and the above object of the present invention is to provide an X-ray intensifying reflector. With respect to, the extremely smooth metal plate as an X-ray reflector is arranged so as to form a two-dimensional elliptical surface, and the X-ray emitted from the X-ray source arranged at one focal point of the ellipse is used as the elliptic surface. It is achieved by increasing the intensity of X-rays entering the linear detector by totally reflecting the light and linearly focusing it on the other focal position.

Further, in order to increase the critical angle of the total reflection of the X-rays, the reflecting surface of the reflecting plate is made of a high-density heavy metal, and the reflecting plates are arranged in multiple layers, and the X wavelength is short. X-rays with long wavelengths should be reflected by an outer reflector, and the reflector should be made of a member (glass or metal plate) with a finish close to a mirror surface as a substrate. A thin film layer made of a polymer material is formed to reduce minute irregularities on the surface of the substrate.
Furthermore, a reflective surface composed of a high-density heavy metal is formed on the thin film layer; the thin film layer is formed by applying a polymer material converted into a polymer to the surface in the form of a solution. It is formed by drying the molecular material in a semi-sealed container (or by heating the semi-polymerized polymeric material and then completely polymerizing it),
The reflecting surface is formed by depositing a heavy metal on the thin film layer; the two-dimensional elliptical surface is formed by fitting a flat reflecting plate to a frame grooved into a desired ellipse. Each of them is achieved more effectively. Further, the X-ray inspection apparatus is achieved by having the X-ray enhanced reflection plate having the above configuration.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing a schematic configuration of an X-ray enhanced reflector (hereinafter referred to as an X-ray reflector unit) according to the present invention, and FIG. 2 is a perspective view showing a schematic configuration of the reflector. There is. It should be noted that FIGS. 1 and 2 schematically show the length of the minor axis of the ellipse in a greatly enlarged manner compared to the actual length. X-ray reflector unit 10 according to the present invention
Is a metal plate (reflector) 11 having a high density and an extremely smooth surface such as gold so as to form a part of the two-dimensional elliptical surface R,
For example, as shown in the figure, two reflection plates 11 are arranged facing each other, and the X-ray source 1 is arranged at one focus position F1 of an ellipse passing through the center of the reflection plate 11 having the two-dimensional elliptical surface. ,
The X-ray 2 emitted from the X-ray source 1 is totally reflected by the reflecting surface 12, and the focal point F2 is linearly formed at a predetermined position as shown in FIG. The signal amount of the used X-ray inspection apparatus is greatly enhanced. The “two-dimensional elliptical surface” referred to in the preferred embodiment of the present invention means the surface of the peripheral wall of the ring-shaped cylinder whose cross section is always the same ellipse.

FIG. 3 is a perspective view showing a structural example of a housing of an X-ray reflection plate unit having the reflection plate 11 described above. In FIG. 3, at both ends of the housing 13, an entrance opening 13a for entering X-rays emitted from the X-ray source 1 is made.
And an emission opening 13b for emitting X-rays that are totally reflected by the reflection plate, and for inserting the reflection plate into which a desired ellipse is grooved by electrical discharge machining or the like on the inner wall portions on both sides. A plurality of grooves 13c are formed at predetermined intervals. In the X-ray reflection plate unit of this example, both ends of a flat metal plate serving as a reflection plate are fitted and fixed in the grooves 13c on both sides of the housing 13 so that the reflection surface of each reflection plate has a desired two-dimensional shape. The layers are arranged so as to face each other so as to form an elliptical surface.

In the example of FIG. 3, four elliptical grooves 13c are formed corresponding to each ellipse having a curvature corresponding to each wavelength of X-rays, and a metal plate is fitted into each groove 13c. so,
Two sets of reflectors are arranged so as to face each other at a target position with respect to a plane passing through the first focus and the second focus (linear focus group) of the ellipse.

FIGS. 4A to 4C show a state in which a reflector is attached to the X-ray reflector unit, and FIG.
Is a front view showing the shape of the entrance opening 13a, FIG.
Is a rear view showing the shape of the emission opening 13b, FIG.
FIG. 3 is a partial side sectional view showing a side surface shape of a reflection plate. In this example, the length of the major axis of the ellipse (≈the length from the first focus to the second focus) = 570, and the entrance opening 13a from the end of the ellipse in the major axis direction (≈the position of the X-ray source). Up to 100 = 100, and the value indicating each size in FIG.
90, depth D = 90, Wi1 = 1.26, Wi2 =
4.46, Wo1 = 1.55, Wo2 = 5.5 (unit is “mm”). And the short wavelength X
The X-ray having a long wavelength is reflected by the inner reflection plate 11-1, and the X-ray having a long wavelength is reflected by the outer reflection plate 11-2.
The portion indicated by the chain double-dashed line in FIG. 4C shows the case where the reflection plate has three layers. In that case, Wi3 = 6.
96, Wo3 = 8.58. These sizes are determined according to the applied X-ray inspection apparatus,
The present invention is not limited to this embodiment. Further, the number of layers of the reflection plate, the shape of the entrance opening 13a, and the shape of the exit opening 13b are not limited to those in this embodiment.

Further, the reflector unit 10 shown in FIG.
Is a mechanism capable of freely adjusting the position and direction in order to accurately adjust the X-ray source 1 so as to pass through the center of the X-ray source 1 and be parallel to the linear detector (screw type or the like in FIG. 3). Adjustment mechanism) is provided.

Now, the reason why the reflectors are arranged in multiple layers as described above will be described. FIG. 5 is a graph showing the relationship between the wavelength and the intensity of X-rays when an electron accelerated to a certain energy is applied to the X-ray target.
The X-rays emitted from the X-ray source consist of continuous X-rays having the shortest wavelength determined by the acceleration energy and characteristic X-rays (dotted lines in FIG. 5) determined by the target substance (element). Further, there is a characteristic that the critical angle of total reflection of X-rays is proportional to the wavelength of X-rays. Here, the critical angle of total reflection is
All X-rays of a certain wavelength or more that are incident at an angle equal to or less than that angle are reflected at an angle equal to the incident angle, but those incident at an angle greater than that mean a critical angle at which they are absorbed without being reflected. Therefore, the reflector for X-rays of short wavelength has a flat 2
It becomes a three-dimensional ellipsoid and becomes bulging for long wavelength X-rays. Therefore, according to the present invention, a reflection plate having a small incident angle with respect to X-rays of a certain short wavelength is arranged inside and a reflection plate with respect to a long wavelength is arranged outside so that X-rays of a wide range of wavelengths can be obtained. The X-ray intensity is efficiently focused by increasing the efficiency.

Generally, the acceleration energy is several tens keV.
Since the one used in the X-ray inspection apparatus is a case where a tungsten target is excited at 50 keV, the maximum intensity of continuous X-rays in FIG. 5 is around 27 keV, and the characteristic X-ray is K Since the line has an energy of 59 keV, it is not excited in this case and becomes an L line and an M line. Figure 3
The X-ray reflector unit 10 shown in FIG. 2 has a wavelength region m (from 30 keV to L which is somewhat higher than the peak of continuous X-rays,
The reflectors are arranged in multiple layers so that X-rays (up to the lines) can be focused particularly efficiently. Of course, it is also possible to reflect X-rays having a short wavelength and energy higher than 30 keV by reducing the incident angle of the reflector. Further, although X-rays having a wavelength longer than that of the L-rays can be taken in, the energy is small and the penetrating power is low, so that the contribution as an input signal is small.

Next, the structure of the reflector contained in the X-ray reflector unit 10 will be described with reference to a specific example.

The refractive index of X-ray is higher than that of visible light or infrared light.
Are very small, so most optical elements that utilize refraction
Instead, we will use total internal reflection instead of an X-ray source.
In order to effectively use the X-rays emitted from the
It is desirable to make the critical angle as large as possible. There
Therefore, as the material of the reflector that constitutes the reflective surface,
It is effective to use heavy metals. Because of the X-ray
The critical angle θc of total reflection is the wavelength of X-rays, and the density of the reflector.
Is ρ, θc ≦ 1.6 × 10⁵× λ × ρ ^1/2And table
The larger the reflector density ρ, the larger the critical angle
This is because that.

Examples of heavy metals include iridium, osmium, platinum, rhenium, neptunium, plutonium, gold, and tungsten in descending order of density. Surface roughness, workability, cost, corrosion resistance, melting point, price, etc. When comprehensively evaluated from various viewpoints, gold, osmium, platinum, iridium and the like are preferable as the heavy metal used for the reflector. However, when such a heavy metal is used alone as a reflector, it is difficult to form a precise two-dimensional ellipsoidal surface having a very smooth surface, and the reflector cannot be thinned to maintain its shape. It becomes a factor that hinders cost reduction and weight reduction.

Therefore, in the preferred embodiment of the present invention,
As shown in the sectional view of FIG. 6, the reflection plate has a structure in which a reflection layer 11c is provided on a member of two layers 11a and 11b for smoothing. The first layer 11a in FIG. 6 is a substrate of a reflection plate, and a light metal (for example, aluminum) or an alloy having a smooth surface and excellent in workability, cost, and weight is used as a material. Is preferred. Board 11a
The upper layer 11b is a layer for further smoothing the surface of the substrate. In this example, the layer of the thin film 11b is formed by coating a polymer material such as acrylic resin on the substrate 11a. ing. The third layer 11c is a reflective layer for totally reflecting X-rays, and has a reflective surface formed by vapor-depositing the above-mentioned heavy metal as a reflector on the layer of the thin film 11b.

Here, the material of the substrate 11a is "aluminum", the material of the thin film 11b is "plastic",
A specific example of the method for manufacturing the reflection plate 11 will be described by taking the case where "gold" is used as the material of the reflection layer 11c as an example.

The width W of the reflecting plate 11 is determined according to the width of the detecting portion of the linear detector, and the depth D is the first and second.
Distance between the focal points of, the arrangement position of the reflector 11 from the X-ray source,
It is determined according to the density of the heavy metal (critical angle of total reflection) and the like.

First, a flat substrate having a thickness of T ₁ which is finished by a precision roll (ultra-precision rolling) to have a finish close to a mirror surface is manufactured. The substrate member is preferably glass or metal, and in this example, thickness T ₁ = 0.3 mm, width W = 90 m.
The substrate is an aluminum plate with m and depth D = 90 mm (step 1). Next, a plastic film is thinly applied in order to reduce minute irregularities on the surface of the aluminum plate. At that time, a thin film (thickness T ₂ = about 0.5 micron in this example) is formed by applying a solution converted to a polymer having a higher molecular weight as a solution or a semi-polymerized product. Yes (step 2). Next, when the thin film hardens, the thin film is dried or polymerized in a semi-sealed container in order to prevent the surface from becoming granular due to moisture in the air or the like. This allows the applied thin film layer to be solidified without changing its volume (step 3). Then, deposit gold with a high density on the plastic film and
Line reflection surface (in this example, gold thickness T ₃ = 200 to 300)
Å About reflective surface) is formed. At that time, gold may be vapor-deposited on the plastic film on which chromium is deposited (step 4). A two-dimensional elliptical surface is formed by fitting the reflecting plate having the reflecting surface precisely into a frame (groove 13c in FIG. 3) grooved into a desired ellipse and fixing it (step 5). Through the above steps, it is possible to manufacture a reflecting plate having a reflecting surface which is extremely smooth and has a large critical angle, and the reflecting surface of each reflecting plate is arranged so as to form a desired two-dimensional elliptical surface. The plate unit can be easily manufactured.

In the above-described embodiment, the case where the reflecting surface forms a two-dimensional elliptical surface has been described as an example. However, the X-ray source and each point of the linear point group are the first. , Second
A three-dimensional ellipsoidal surface formed by a group of ellipses serving as a focal point is used as a reflecting surface, and a reflecting plate having the reflecting surface is arranged so that X-rays from the X-ray source at the positions of the first focal points are positioned at the positions of the second focal points. It may be made to converge linearly. Further, the case where the X-rays are focused linearly has been described as an example, but an ellipsoidal surface of an ellipsoid is used as a reflecting surface, and an annular reflecting plate or a plurality of reflecting plates having the reflecting surface is arranged, and the X-rays are focused on a point. You may make it converge in a shape.

[0022]

As described above, according to the present invention, the X-rays emitted from the X-ray source arranged at one focus position are totally reflected by the elliptical surface and are linearly focused at the other focus position. Thus, it is possible to realize a device that significantly increases the signal amount of the X-ray inspection apparatus using the linear detector. The X-ray inspection apparatus tends to reduce the size of the detector in order to improve the resolution. This inevitably leads to a decrease in the signal amount, but by applying the X-ray enhanced reflection plate according to the present invention, the X-rays that have been thrown away without being incident on the X-ray detection unit until now can be converted into wavelengths. Can be acquired as an effective signal with a gain of several tens of times when it is as long as 2.3 Å and about 10 times when it is as short as 0.4 Å. That means high resolution and fast processing are possible.
The effect is extremely large. Therefore, it can be suitably applied to various industrial inspection devices such as an X-ray microscope, a foreign substance inspection device, a material surface inspection device, and a fluorescent X-ray analysis device, and a medical X-ray device such as an X-ray diagnostic device.

Further, according to the invention of claim 2, the critical angle of total reflection of X-rays can be increased, and
Since the X-rays having a plurality of wavelengths can be linearly focused, the efficiency of the X-ray intensity can be improved. Further, according to the inventions according to claims 3 and 4, since it is possible to provide a reflector having an extremely smooth reflecting surface, total reflection of X-rays can be accurately caused, and X on the irradiation area can be accurately reflected. It is possible to avoid uniforming the line distribution and reducing the X-ray dose due to diffused reflection of X-rays and transmission of the reflector. Further, according to the invention of claim 5, a precise two-dimensional elliptical surface can be easily formed, so that the X-ray enhanced reflection plate can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a schematic configuration of an X-ray enhanced reflection plate according to the present invention.

FIG. 2 is a perspective view schematically showing a schematic configuration of an X-ray enhanced reflection plate according to the present invention.

FIG. 3 is a perspective view showing a configuration example of a housing of an X-ray reflector unit according to the present invention.

FIG. 4 is a diagram showing a state in which a plurality of reflectors are mounted on the X-ray reflector unit according to the present invention.

FIG. 5 is a diagram showing a relationship between an X-ray wavelength and energy.

FIG. 6 is a cross-sectional view showing an example of the configuration of a reflection plate according to the present invention.

[Explanation of symbols]

F1 first focus position F2 second focus position R two-dimensional ellipsoid 1 X-ray source 2 X-ray 10 X-ray reflector unit 11 reflector 11a substrate (first layer) 11b Thin film layer (second layer) 11c Reflective layer (third layer) 12 Reflective surface 13 housing 13a entrance opening 13b exit opening 13c Groove for inserting reflector

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01N 23/02 G01N 23/02 H05G 1/00 H05G 1/00 G (72) Inventor Tai Saito Tokyo Metropolitan Chofu 1-43, Ichi-Tama River Stock F-term within Token Co., Ltd. (reference) 2G001 AA01 CA01 DA08 4C092 AB30 AC01 AC08 BD10 4C093 AA30 CA50 EA20

Claims (6)

[Claims] 1. An extremely smooth metal plate is arranged as an X-ray reflector so as to form a two-dimensional elliptical surface, and X-rays emitted from an X-ray source arranged at one focal point of the ellipse are described above. An X-ray intensifying reflector characterized in that the intensity of X-rays entering a linear detector of X-rays is enhanced by totally reflecting on an elliptical surface and linearly focusing on the other focal position. . 2. The reflection surface of the reflection plate is made of a high-density heavy metal in order to increase the critical angle of the total reflection of the X-rays, and the reflection plates are arranged in multiple layers to provide a short wavelength X-ray. The X-ray enhanced reflection plate according to claim 1, wherein the X-ray having a long wavelength and the X-ray having a long wavelength are reflected by the reflection plate on the outside. 3. A thin film layer made of a polymer material is formed on the reflection plate as a substrate with a member having a finish close to a mirror surface as a substrate to reduce minute irregularities on the surface of the substrate. The X-ray enhanced reflector according to claim 1 or 2, wherein a reflective surface made of a heavy metal having a high density is formed on the layer. 4. The thin film layer is formed by applying a polymer material converted to a polymer on the surface in the form of a solution and drying the polymer material in a semi-sealed container. The X-ray intensifying reflector according to claim 3, wherein the reflecting surface is formed by depositing a heavy metal on the layer of the thin film. 5. The two-dimensional elliptical surface is formed by fitting a flat reflection plate on a frame grooved into a desired ellipse. X-ray enhanced reflector. 6. An X-ray inspection apparatus comprising the X-ray enhanced reflection plate according to claim 1.