JP2005227058A - Small-sized point x-ray source using pore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray source of a point X-ray source with high brightness realized by a small-sized device, and capable of irradiating a sample in the atmosphere. <P>SOLUTION: In a method using an X-ray as a point light source, a primary beam is injected, in a vacuum condition, from one end of a pore constituted of a target material generating the X-ray by irradiation of the primary beam to irradiate an inner wall of the pore, and the generated X-ray is converged by reflection in the pore to outgo from the other end of the pore. In this device used as the small-sized point X-ray source provided with the pore constituted of the target material generating the X-ray by the irradiation of the primary beam, the pore functions as an X-ray generating part for generating the X-ray by the irradiation of the primary beam, and functions as an optical system for converging the generated X-ray. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a small-sized point X-ray source, and more particularly to a high-intensity point X-ray source realized by a small apparatus, which can irradiate a sample in the atmosphere. It is.

  X-rays are used in a very wide range of fields, such as non-destructive inspection of samples and structural analysis of materials, as well as medical fields such as radiographic imaging. Conventionally, when X-rays are used, a flat or curved target material is irradiated with an electron beam accelerated to about several tens to one hundred keV in a vacuum, and the X-rays generated there are converted to X containing the target material. The light is condensed by an X-ray optical system independent from the line generating means and used (for example, see Non-Patent Document 1).

Among such X-ray sources, particularly when a high-luminance point light source is required, it is necessary to narrow down the electron beam, which is the primary beam, so that the region where X-rays are generated is a minute point.
However, at this time, since the concentrated electron beam is irradiated to a limited and very narrow region, damage caused by local heat generation becomes a serious problem in the target material. Further, since X-rays are generated isotropically, the X-ray dose incident on the X-ray optical system depends on the distance between the target material and the X-ray optical system, and in order to increase the efficiency as a light source, The generation amount must be increased, and a high-performance X-ray optical system must be used. Furthermore, in order to extract X-rays generated in a vacuum to the atmosphere, it is necessary to pass the X-rays through a window made of an appropriate material. Due to the increase, it was impossible to obtain strong X-rays in the atmosphere.

As another method, there is a method using a large accelerator (synchrotron) and using the emitted light generated when high energy electrons (> several hundred MeV) are deflected in a magnetic field as a high brightness X-ray source. However, this method requires large-scale equipment and the facilities that can be used are very limited.
Toshiyuki Shono, 1 other, “Introductory Instrumental Analytical Chemistry”, Sankyo Publishing Co., Ltd., October 10, 1988, p. 99-104

  It is an object of the present invention to provide a high-intensity point X-ray source realized by a small apparatus and capable of irradiating a sample in the atmosphere.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that an X-ray generation unit that generates X-rays by irradiating a primary beam to a pore formed of a target material, and an optical that focuses the generated X-ray The present invention was completed by adopting it as a system.

  That is, the present invention is a method of using X-rays as a point light source, in which a primary beam is incident from one end of a pore formed of a target material that generates X-rays by irradiation with the primary beam. Then, the inner wall of the pore is irradiated, and the generated X-ray is focused by reflection in the pore and taken out from the other end of the pore.

Further, the present invention is characterized in that, in the above method, the line width of the primary beam is made smaller than the width of the pore entrance through which the primary beam is incident.
Further, the present invention is characterized in that, in any of the above methods, X-rays are extracted directly from the pores under atmospheric pressure.

  Furthermore, the present invention is an apparatus that can be used as a small-sized point X-ray source having a pore composed of a target material that generates X-rays by irradiation with a primary beam, the pore being formed by irradiation with a primary beam. It functions as an X-ray generator that generates X-rays, and also functions as an optical system that focuses the generated X-rays.

  A major feature of the present invention is that a high-intensity point X-ray source can be formed with a small apparatus. According to the small point X-ray source of the present invention, X-rays of various wavelengths can be obtained by appropriately changing the target material that generates X-rays.

  In addition, according to the present invention, a high-intensity X-ray point light source that has been difficult to form can be formed with a small generator, and the ripple effect is the development of a small X-ray microscope. It is very big.

  In the present invention, the primary beam generated by the primary beam generating means in a vacuum is incident from one end of a pore composed of a target material that generates X-rays by primary beam irradiation, and irradiates the inner wall of the pore. X-rays are generated. The generated X-rays are focused by reflection in the pores, and are extracted and used in the atmosphere or vacuum without passing through the window.

  In the present invention, as the target material, a target material generally used for the purpose of generating X-rays by primary beam irradiation can be used. The material of the target material can be appropriately selected according to the wavelength of X-rays to be generated. The “primary beam” is a beam for irradiating the target material to convert it into X-rays, and is, for example, an electron beam or an ion beam. The primary beam can be supplied using means known in the art such as, for example, an electron gun, an ion beam generator. Before the primary beam is incident on the aperture, it is preferably focused to a suitable line width by any means known in the art such as an electromagnetic lens.

  The present invention is an invention having a remarkable feature in adopting “a fine hole made of a target material” in order to convert a primary beam into X-rays. It is possible to form an x-ray source. In the present invention, the pore has not only a function as an X-ray generator, but also a function as an optical system for focusing the generated X-ray. The inner diameter of the pore is at most about 10 μm. When the inner diameter is about 10 μm or less, gas molecules hardly pass through the pores, and the airtightness of the X-ray generation part can be kept sufficiently high. The length of the pores (thickness of the target material) is preferably in the range of about 100 μm to several mm. The shape of the inner wall of the pore is preferably smooth in order to increase the reflection efficiency of generated X-rays.

  The primary beam is introduced into the pore from the entrance of the pore for entering the primary beam, and collides with the inner wall of the pore. X-rays are generated by irradiating the inner wall with an electron beam, and the generated X-ray collides with the inner wall of the pore and converges while repeating reflection, and is taken out from the other end of the pore. Of the X-rays generated inside the pores, those incident on the inner wall of the pores at a shallow angle are totally reflected, so that the X-rays can be efficiently extracted from the pore outlet.

  When irradiating the inner wall of the pore with the primary beam, it is preferable to adjust the electromagnetic lens to focus the primary beam so that the line width of the primary beam is smaller than the width of the entrance of the pore. By doing so, all electrons are introduced into the pores of the target material and used for X-ray generation.

  In addition, by irradiating the primary beam into the inside of the pore at an angle close to parallel to the inner wall surface, the irradiation surface to the inner wall of the pore can be increased and the energy density of the primary beam is reduced. The local heat generation of the material can be suppressed and damage can be minimized.

Furthermore, the X-rays generated in the pores can be easily condensed by making the pore outlet for extracting X-rays narrower than the pore inlet for entering the primary beam.
In the present invention, since the atmosphere outside the pore outlet can be set to atmospheric pressure, a high-intensity point X-ray source can be formed in the atmosphere.

  In accordance with the present invention, a pore formed of a target material that generates X-rays by irradiation with a primary beam functions as an X-ray generator and an optical system that focuses the generated X-rays. A small and high-brightness point X-ray source that has been possible can be realized. A small point X-ray source including a pore, a primary beam generating means for generating a primary beam in a vacuum, and an electromagnetic lens for adjusting the primary beam to an appropriate line width is currently generally used, for example. It can be realized as large as a CRT for a home TV.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this Example is one aspect | mode of this invention and does not limit this invention in any way.
Example Example 1
FIG. 1 shows a schematic diagram of a point X-ray source which is one embodiment of the present invention. FIG. 1A is an overall view, and FIG. 1B is a cross-sectional view of a pore portion. In this embodiment, an electron beam generated by an electron gun in a vacuum is focused by an appropriate electromagnetic lens, and the focused electron beam is irradiated onto the inner wall of a pore formed in the target material to convert it into X-rays. . By adjusting the electromagnetic lens to focus the electron beam and making the electron beam line width smaller than the width of the entrance of the pore, all electrons are introduced into the pore of the target material and used for X-ray generation Is done. As shown in FIG. 1B, an electron beam is incident on the inside of the pore at an angle close to parallel to the inner wall surface, so that a wide area can be irradiated and generated along the electron range. X-rays can be used efficiently.

Example 2
Another embodiment of the present invention is shown in FIG. FIG. 2 is a cross-sectional view of a pore in which the inner wall of the pore is not parallel but has an angle, that is, the pore entrance for emitting an electron beam is wide and the pore exit for emitting an X-ray is thin. It is. Other than the target material, the configuration and arrangement of an electron gun, an electromagnetic lens, and the like are the same as in the first embodiment. In this aspect, the X-ray generated in the pores can be easily condensed by making the pore outlet for emitting X-rays thinner than the pore inlet for entering the electron beam. It is possible to obtain X-rays with higher brightness.

1A and 1B are schematic views showing an aspect of the point X-ray source of the present invention. FIG. 1A is an overall view, and FIG. 1B is a cross-sectional view of a pore portion. FIG. 2 is a cross-sectional view of a point X-ray source according to another aspect of the present invention, in which the inner wall of the pore is not parallel and has an angle.

Claims (4)

  A method of using X-rays as a point light source, in which a primary beam is incident from one end of a pore made of a target material that generates X-rays by irradiation of the primary beam in a vacuum. A method of irradiating an inner wall, focusing generated X-rays by reflection in the pores, and taking out from the other end of the pores.   2. The method according to claim 1, wherein the line width of the primary beam is made smaller than the width of the pore entrance through which the primary beam is incident.   The method according to claim 1 or 2, wherein X-rays are extracted directly from the pores under atmospheric pressure. An apparatus that can be used as a small point X-ray source having a pore made of a target material that generates X-rays by irradiation with a primary beam, the X-ray generating X-rays by irradiation with a primary beam An apparatus that functions as a ray generator and functions as an optical system that focuses generated X-rays.