JP3455595B2 - Radiation magnification observation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image magnifying observation apparatus capable of observing a sample with X-rays and other radiation.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view showing the structure of a conventional radiographic image magnifying and observing apparatus. As shown in the figure, in the conventional radiographic image magnifying observation apparatus, a grazing incidence reflecting mirror 101 and a stopper 102 are arranged inside a substantially cylindrical housing 100, an entrance window 103 is provided on one end surface 100a of the housing 100, and another end surface is provided. The phosphor screens 104 are formed on the respective 100b. In addition, the housing 10
0, the sample stage 105, the filter 1 near the entrance window 103.
06 and an X-ray source 107 are installed, and a camera 108, a frame memory 109, and a monitor 110 are installed near the phosphor screen 104.

The operation of this device will be described below. First, the X-ray source 1
The X-ray emitted from 07 is transmitted through the filter 106, wavelength-limited, and enters the sample 111 fixed to the sample stage 105. The X-ray transmitted through the sample 111 is incident on the oblique incidence reflecting mirror 101 through the incident window 103. The incident X-rays are magnified by the oblique incidence reflecting mirror 101, and the X-rays that have passed through the stopper 102 are imaged on the photocathode 112 as an X-ray image. Here, the stopper 102 prevents unnecessary X-rays from entering the photocathode 112. When X-rays are incident on the photocathode 112, photoelectrons are emitted from the back surface of the photocathode 112, and the emitted photoelectrons are microchannel plate (MCP) 113.
To form an optical image on the phosphor screen 104. This optical image is taken into the camera 108, then temporarily stored in the frame memory 109, and then given to the monitor 110 to display the optical image.

[0004]

By the way, it is the processing accuracy of the reflecting surface of the grazing incidence reflecting mirror 101 that determines the resolution of the conventional radiation magnifying observation apparatus. For example, when using X-rays having a wavelength of several nm, a predetermined level of resolution can be obtained unless the total reflection surface of the grazing incidence reflecting mirror 101 is included in the surface roughness of several nm or less and the shape error of sub-μm or less. Absent.

However, the above-mentioned accuracy can be achieved by only a part of the reflecting surface, but it is difficult to achieve it over the entire reflecting surface, so that a predetermined level of resolution cannot be obtained.

It is an object of the present invention to solve the above problems and provide a radiation magnifying observation apparatus having a high resolution.

[0007]

In order to solve the above-mentioned problems, a radiation magnifying and observing apparatus of the present invention magnifies a radiation source for emitting radiation toward a position where a sample is arranged and an image of the radiation transmitted through the sample. A radiation magnifying and observing device comprising a substantially cylindrical oblique-incidence reflecting mirror for forming an image and a detection unit for detecting a radiation image formed by the oblique-incidence reflecting mirror.
An opening that is arranged close to the entrance surface or the exit surface of the grazing incidence reflecting mirror and is substantially parallel to these surfaces, and allows the radiation reflected at a predetermined portion of the reflecting surface of the grazing incidence reflecting mirror to pass through a partial area of the peripheral portion. And a shield plate rotatable about the central axis of the oblique incidence reflecting mirror.

Alternatively, the apparatus for magnifying radiation according to the present invention comprises a radiation source which emits radiation toward a position where the sample is arranged, and a substantially cylindrical oblique-incidence reflecting mirror which magnifies and forms an image of the radiation transmitted through the sample. And a detection means for detecting a radiation image magnified / formed by the oblique incidence reflecting mirror, which is close to the entrance surface or the exit surface of the oblique incidence reflecting mirror and Placed almost parallel,
A shielding plate having an opening through which the radiation reflected at a predetermined portion of the reflecting surface of the oblique incidence reflecting mirror passes is provided in a partial region of the peripheral portion, and the oblique incidence reflecting mirror is rotatable about its central axis.

[0009]

According to the radiation magnifying and observing apparatus of the present invention, the radiation emitted from the radiation source passes through the sample and enters the oblique incidence reflecting mirror. The incident radiation is magnified and imaged by the grazing incidence reflecting mirror, given to the detecting means, and detected as an X-ray image.
At a position close to the entrance surface or the exit surface of the oblique incidence reflecting mirror,
A shield plate is arranged substantially parallel to these planes. This shielding plate has an opening in a part of the peripheral portion thereof, so that X-rays (or X-rays reflected by a part of the reflecting surface of the oblique incidence reflecting mirror) It passes through this opening and reaches the detection means. Further, the X-rays that enter the other part of the reflecting surface of the oblique incidence reflecting mirror (or the X-rays that are reflected by the other part of the reflecting surface of the oblique incidence reflecting mirror) are shielded by the shielding plate, so that they are detected by the detecting means. Never reach. For this reason, it is possible to magnify and form an X-ray image by selectively using a portion of the reflecting surface of the grazing incidence reflecting mirror, which has high processing accuracy.
A high-resolution X-ray image can be detected by the detection means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing a cross-sectional structure of the radiographic image magnification observation apparatus according to the present embodiment. From the figure,
The radiation image magnifying and observing apparatus of the present embodiment is an oblique-incidence reflecting mirror 11 that magnifies and forms an X-ray image inside a substantially cylindrical casing 10.
In addition, a disk-shaped stopper 12 which has an opening 12a formed in a partial region of the peripheral portion and which allows only a part of the X-ray that has passed through the oblique incidence reflecting mirror 11 and a worm 13 with a shaft which rotates the stopper 12 are incorporated. ing. An entrance window 14 is provided on one end surface 10a of the housing 10, and a fluorescent screen 15 is provided on the other end surface 10b.
And the photocathode 16 is formed at the image forming position of the X-ray by the oblique incidence reflecting mirror 11. Also, the photocathode 1
Microchannel plate (M
CP) 17 is arranged. Further, the sample table 18, the filter 19, the X-ray source 2 are provided in the vicinity of the entrance window 14 of the housing 10.
0 is installed, and a camera 21, a frame memory 22, and a monitor 23 are installed near the fluorescent screen 15. Furthermore, coils 24 and 25 are wound around the outer periphery of the housing 10 between the photocathode 16 and the phosphor screen 15.

A gear 12b for adjusting the rotation angle is formed on the outer peripheral edge of the stopper 12 to form a worm wheel. The worm 13a of the worm 13 with a shaft is meshed with the gear 12b, and the stopper 12 is rotated by rotating the worm 13 with a shaft. The shaft-mounted worm 13 is driven by a pulse motor 26 or the like provided outside the housing 10 so that the rotation angle of the stopper 12 can be set accurately.

The radiation image magnifying observation apparatus of this embodiment operates as follows. First, the sample 27 to be observed is placed on the sample table 1
8 and is arranged between the entrance window 14 and the filter 19. Next, when X-rays are emitted from the X-ray source 20, X
The line passes through the filter 19 and is wavelength-limited, and the sample stage 18
It is irradiated onto the sample 27 fixed to the. X-ray is sample 27
An X-ray image is formed after passing through. The transmitted X-rays pass through the entrance window 14 and enter the oblique incidence reflecting mirror 11, and an X-ray image enlarged by the oblique incidence reflecting mirror 11 is formed on the photocathode 16. Photoelectrons corresponding to the X-ray image are emitted from the back surface of the photocathode 16, and the electron image by the photoelectrons is enlarged by the coils 24 and 25. Then, the magnified electronic image is multiplied by the MCP 17 and then focused on the fluorescent screen 15 to obtain an optical image. The optical image formed on the fluorescent screen 15 is captured by the camera 21, temporarily stored in the frame memory 22, and then provided to the monitor 23 equipped with a CRT or the like. Further, the frame memory 22 has a function of synthesizing an image currently stored and a newly given image.

The feature of this embodiment is that it is provided with a stopper 12 for passing a part of the X-rays reflected by the reflecting surface of the oblique incidence reflecting mirror 11. By this stopper 12, the X-rays reflected by most of the reflecting surface of the grazing incidence reflecting mirror 11 are shielded, and only the X-rays reflected by the desired portion of the reflecting surface reach the photocathode 16 and the X-rays are reflected. An image is formed. The stopper 12 can be rotated by the drive gear 13,
The opening 12a can be moved to a predetermined position. As a method of observing the sample 27 using the apparatus of this embodiment, first, the stopper 12 is rotated by the drive gear 13 to move the opening 12a to a predetermined position, and then the stopper 12 is fixed. With the first method of observing the image on the monitor 23, the stopper 12 is rotated once by the drive gear 13, and an optical image is obtained every time the stopper 12 is rotated by a predetermined angle.
There is a second method in which the images are captured, the images obtained at predetermined angles are combined, and the combined image is observed on the monitor 23.
Hereinafter, the first observation method and the second observation method will be separately described.

The first observation method is as follows: First, the grazing incidence reflecting mirror 1
It is used when a part of the reflecting surface of No. 1 has a high processing accuracy. In order to form a high-resolution X-ray image on the photocathode 16, it is necessary to set the processing accuracy (surface roughness, shape error) of the grazing incidence reflecting mirror 11 to the nm order. This is because processing with such accuracy is impossible with the current processing technology. Therefore, of the reflecting surfaces of the grazing incidence reflecting mirror 11, a surface having a processing accuracy on the order of nm is selected, and only the X-ray reflected by this surface passes through the opening 12a of the stopper 12 and reaches the photocathode 16. ing. Therefore, a high-resolution X-ray image is formed on the photocathode 16 and a high-resolution optical image is formed on the fluorescent screen 15.
Since most of the X-rays reflected by the reflecting surface of the oblique incidence reflecting mirror 11 are blocked by the stopper 12, the X-ray dose reaching the photocathode 16 is very small. Therefore, in this observation method, it is necessary to perform long-time exposure to secure a sufficient X-ray dose.

The first observation method is the oblique incidence reflecting mirror 1
Even if there is no highly processed portion on the reflecting surface of No. 1, the resolution direction of the image captured by the camera 21 is one direction (the direction along the line segment connecting the rotation axis of the stopper 12 and the opening 12a).
It is used when it is enough. The X-ray image magnified by using the reflection surface of the oblique-incidence reflecting mirror 11 having low processing accuracy is larger than that of the X-ray image enlarged by using the entire reflecting surface of the oblique-incidence reflecting mirror 11 after removing the stopper 12. The vertical resolution is high. This is because the stopper 12 shields X-rays that deteriorate the resolution reflected by other portions of the reflecting surface. Therefore, when the resolution direction of the image is only one direction, this method is used even when the processing accuracy of the entire reflecting surface is low. Since the degree of improvement in the resolution depends on the processing accuracy (surface roughness, shape error) of the surface to be used, it is necessary to set the reflective surface to be used to the surface having the highest processing accuracy of the entire reflective surface.

Next, the second observation method will be described.
The second observation method is when the reflecting surface of the grazing incidence reflecting mirror 11 does not have a portion with high processing accuracy, and when the image captured by the camera 21 is required to have high resolution in all directions. Used for. In this observation method, first, the sample 27
The surface is irradiated with X-rays, and the X-rays transmitted through the sample 27 are reflected by the reflecting surface of the oblique incidence reflecting mirror 11. Of the X-rays reflected by this reflecting surface, the X-rays passing through the opening 12a of the stopper 12
The rays reach the photocathode 16 and form an enlarged X-ray image on the photocathode 16. Upon arrival of X-rays, photoelectrons are emitted from the photocathode 16 and the photoelectrons are multiplied by the MCP 17 to produce a fluorescent screen 1.
An enlarged optical image is formed at 5. This optical image is picked up by the camera 21 and observed by the monitor 23 via the frame memory 22.

Next, the stopper 12 is slightly rotated. The angle of rotation is set so that there is no gap between the opening 12a at the previous position and the opening 12a at the next position, depending on the size of the opening 12a (the size of the opening 12a is that of the oblique reflection mirror 11). Although it depends on the processing accuracy of the reflecting surface, it is considered that the opening area of the emitting surface of the grazing incidence reflecting mirror 11 may be 20% or less from the experiment by the inventor conducted with visible light).

After that, the sample 27 is irradiated again with X-rays, the transmitted X-rays from the sample 27 are enlarged, an optical image of this X-ray image is taken by the camera 21, and the obtained image is stored on the frame memory 22. Combine with previous image. Furthermore, by rotating the stopper 12 to change the position of the opening 12a and capturing an image,
Combine with the previous two images. After that, this process is repeated until the opening 12a of the stopper 12 returns to its original position (until one rotation). The composite image obtained in this way is
The image has a higher contrast and a higher resolution than an image using the entire reflecting surface of the oblique incidence reflecting mirror 11.

In this embodiment, the resolution is improved by using a special method for combining the images. Next, this image processing method will be described with reference to FIGS.

An oblique-incidence reflecting mirror 11 as shown in FIG.
When the sample 27 having the lattice pattern as shown in FIG. 2A is imaged by using the conventional stopper 12 'which is slightly smaller than the exit surface of the image, the whole image becomes blurred as shown in FIG. 3A. . This is also clear from the graph of the relative luminance distribution in FIG. That is, in the graph of FIG. 3B, the difference between the maximum luminance and the minimum luminance is small, and the contrast between the bright portion and the dark portion is small. From this, it can be seen that the image is not clear.

By the way, as shown in FIGS. 2 (c) to 2 (e), the composite image obtained by simply adding the images picked up by rotating the stopper 12 of this embodiment by a predetermined angle is shown in FIG.
The image becomes blurred as shown in (a). The graph of FIG. 5 (b) has a larger difference between the maximum brightness and the minimum brightness than the graph of FIG. 3 (b), but this composite image is only the addition of images in three directions, and the addition of images in all directions. When combined, it is expected that the image has almost the same resolution as the image of FIG. The reason is as follows. An X-ray image of an X-ray that has passed through the opening 12a of the stopper 12 has a high resolution in the direction along the line segment 12b connecting the opening 12a and the rotation axis, but a low resolution in the direction perpendicular to this line segment 12b. Therefore, if a plurality of images captured each time the stopper 12 is rotated are simply added, a component in the direction of low resolution is also added, and the resolution of the composite image is relatively low. Specifically, FIG.
The transmission image of the sample 27 having the lattice pattern of (a) is shown in FIG.
The stopper 1 having the opening 12a at the upper portion as shown in (c)
When the image is picked up using 2, the line in the Y-axis direction can be obtained with high resolution as shown in FIG. 4A, but the line in the X-axis direction perpendicular thereto is blurred. On the contrary, when an image is captured using the stopper 12 having the opening 12a on the right side as shown in FIG. 2D, the line in the Y-axis direction is blurred and the line in the X-axis direction becomes clear. Therefore, when these two images are added together, the resolution is lowered as a whole. Furthermore, if this is done in all directions and all images are added,
The image has a low resolution comparable to the image picked up by the conventional stopper 12 'in (b).

Here, paying attention to a specific portion in the object to be photographed, a signal (transmission X-ray) from that portion is shown in FIG.
When an image is formed by passing through one of the openings 12a of the stopper 12 of FIG. 2 and the stopper 12 of FIG. 2D, the signal amount when the image is clearly visible even at the same image forming position is the signal when the image is blurred. It is larger than the amount (when it is blurred, the signal to be imaged there spreads to surrounding pixels). Therefore, if the larger one of each pixel of both images is selected and output, an image of higher image quality is obtained than an image obtained by simply adding both images.

Therefore, instead of adding up the images, the images are compared pixel by pixel and the maximum value is selected to form the final image.
An image having a higher resolution than the image taken by the stopper 12 'shown in (b) can be obtained. However, in this case, the background of a portion where there is originally no signal (a portion that becomes a shadow and does not have a transmitted X-ray) also rises, but the resolution is still better than that of an image that is simply added. Further, in the image in which the maximum value is selected, if the signal amount is large, an even better image can be obtained by applying an offset to cut the background component. Further, these processes are performed by the signal amount (X
It is effective when the dose is high. An example of this image is shown in FIG.
It shows in (a). From this figure, it can be seen that an image having a higher resolution than that of the image of FIG. In particular, FIG.
It can be said that an extremely clear image was obtained because the difference between the maximum luminance and the minimum luminance in the graph shown in (b) is large.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in this embodiment, the stopper 12 is provided on the exit side of the oblique incidence reflecting mirror 11, but it may be provided on the entrance side of the oblique incidence reflecting mirror 11. Further, the stopper 12 may be provided in front of the sample 27 (between the X-ray source 20 and the sample 27). When placed in front of the sample 27, the X-ray dose irradiated to the sample 27 can be reduced and the radiation damage given to the sample can be reduced. Stopper 12
In the embodiment of FIG. 1 in which the sample is placed behind the sample 27, an image is formed using only a part of the X-ray transmitted through the sample 27,
The rest is discarded. That is, the sample 27 is irradiated with unnecessary X-rays. In particular, when combining the images by rotating the stopper 12, if it is necessary to combine, for example, n images in order to obtain one image, it is n times as large as that in the conventional case where imaging is performed by one irradiation. Many same sample 27 X
The line is illuminated. This is a problem in the sample 27 such as a biological sample which may be damaged by radiation. Therefore, by placing the stopper 12 in front of the sample 27, the X-rays that irradiate the sample 27 are suppressed to a necessary minimum (in the first observation method, only a part of the opening 12a is effective, so that the effect is great). Even in the second observation method in which the stopper 12 is rotated, there is no difference from the case where an image is taken at one time with all openings. An embodiment in which the stopper 12 is placed in front of the sample 27 is shown in FIG. An oblique-incidence reflecting mirror 11a for condensing light is installed in front of the X-ray source 20 and the sample 27, and a stopper 12 may be placed on either the incident side or the emitting side (the opening 12a of the stopper 12 provided here). Note that the position of is in a direction shifted by 180 ° in the oblique-incidence reflecting mirror 11b for image formation.
For example, the oblique incidence reflecting mirror 11b for image formation in the first observation method
When the portion A of A is selected and used, the position of the opening 12a of the stopper 12 is in the B direction. ).

Further, in this embodiment, the stopper 12 is rotated to change the reflecting surface of the grazing incidence reflecting mirror 11 for reflecting X-rays, but the grazing incidence reflecting mirror 11 itself may be rotated. Further, in the present embodiment, a worm gear using a disk-shaped stopper 12 and a worm 13 with a shaft which form a worm wheel is used as the rotating mechanism.
Without being limited to this mechanism, for example, Japanese Patent Laid-Open No. 2-2
The rotating mechanism of the diaphragm means described in Japanese Patent No. 2589 (Radiation Enlargement Observation Device) may be used.

[0026]

As described in detail above, in the radiation image magnifying and observing apparatus of the present invention, even if most of the processing accuracy of the reflecting surface of the grazing incidence reflecting mirror is poor, the processing accuracy of the reflecting surface is good. If there is even a part of the portion, only the radiation reflected by the portion can pass through the opening of the shield plate. Therefore, the resolution of the radiation image in which the radiation that has passed through the opening of the shielding plate is magnified / formed is very high, and the radiation image of high resolution is detected by the detection means.

[0027]

[Brief description of drawings]

FIG. 1 is a perspective view showing a cross-sectional structure of a radiographic image magnification observation apparatus according to the present embodiment.

FIG. 2 is a diagram showing shapes of a sample and a stopper.

FIG. 3 is a diagram showing an enlarged image and a luminance distribution of this image.

FIG. 4 is a diagram showing an enlarged image and a luminance distribution of this image.

FIG. 5 is a diagram showing an enlarged image and a luminance distribution of this image.

FIG. 6 is a diagram showing an enlarged image and a luminance distribution of this image.

FIG. 7 is a cross-sectional view showing the structure of a radiographic image magnification observation apparatus according to another embodiment.

FIG. 8 is a sectional view showing the structure of a conventional radiographic image magnifying observation apparatus.

[Explanation of symbols]

10 ... Housing, 11 ... Oblique incidence reflecting mirror, 12 ... Stopper, 1
2a ... aperture, 12b ... gear, 13 ... worm with shaft, 1
4 ... Incident window, 15 ... Phosphor screen, 16 ... Photocathode, 17 ... Microchannel plate, 18 ... Sample stage, 19 ... Filter, 20 ... X-ray source, 21 ... Camera, 22 ... Frame memory, 23 ... Monitor, 24 , 25 ... coil, 26 ... pulse motor, 27 ... sample.

Continuation of the front page (56) References JP-A-2-22599 (JP, A) JP-A 61-186900 (JP, A) Actual development Sho-61-67549 (JP, U) (58) Fields investigated (Int .Cl. ⁷ , DB name) G01N 23/00-23/223 G21K 7/00

Claims (2)

(57) [Claims] 1. A radiation source that emits radiation toward a position where a sample is arranged, and a magnified image of the radiation transmitted through the sample.
What is claimed is: 1. A radiation magnifying and observing device comprising: a substantially cylindrical oblique-incidence reflecting mirror for forming an image; and detection means for detecting a radiation image magnified / formed by the oblique-incidence reflecting mirror. A shield plate which is arranged close to the surface or the emission surface and is arranged substantially parallel to these surfaces, and which has an opening in a partial area of the peripheral portion through which the radiation reflected by a predetermined portion of the reflection surface of the oblique incidence reflecting mirror passes. The radiation magnifying observation apparatus, comprising: the shielding plate rotatable about a central axis of the oblique incidence reflecting mirror. 2. A radiation source that emits radiation toward a position where a sample is arranged and an image of the radiation that has passed through the sample.
What is claimed is: 1. A radiation magnifying and observing device comprising: a substantially cylindrical oblique-incidence reflecting mirror for forming an image; and detection means for detecting a radiation image magnified / formed by the oblique-incidence reflecting mirror. A shield plate which is arranged close to the surface or the emission surface and is arranged substantially parallel to these surfaces, and which has an opening in a partial area of the peripheral portion through which the radiation reflected by a predetermined portion of the reflection surface of the oblique incidence reflecting mirror passes. A radiation magnifying observation apparatus, comprising: the grazing incidence reflecting mirror rotatable about a central axis thereof.