JPH06215711A - Parallel x-ray source - Google Patents

Abstract

PURPOSE:To provide X-ray beams in parallel to each other by using a small device at low power by filling a metal in the pore of a planar alumite film, and by having electrons collided with the target surface, for which metal is coated on the pore filled with metal. CONSTITUTION:Electron beams e<-> directly drawn from a cathode 1 are flowed in a target 3 by a high electric field applied between the cathode 1 and an electrode 12, and a part of the kinetic energy accelerated at high speed by the high electric field, is emitted as a characteristic X-ray of target atom. A porous film 14 which is the other side of a target film 11, is formed of a thin film consisting of a positive electrode alumite oxide and a metal pillar. When the X-rays penetrate the film 14, the component perpendicular to the film surface of the X-rays passes only the alumite part, while the X-rays distracted from the normal of the film surface are absorbed in the metal pillar. Thus only the X-rays of the component in the normal direction are emitted from the target 3. X-rays beams in parallel to each other, can thus be provided by a small device at low power.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a parallel X-ray source for obtaining parallel X-rays.

[0002]

2. Description of the Related Art Conventionally, an ordinary optical microscope is used for inspection of small parts such as reinforced belts containing steel wires, fiber sleeves, wire dies, electronic parts, etc. Measurements could not be used. For this reason, lots of products were inspected by cutting a sample of the completed parts and performing optical inspection, but it was time-consuming, and because it was a destructive test, 100% inspection was impossible in principle. .

An X-ray exposure method is known as a technique for forming a fine pattern, but in this case as well, parallel X-rays are required.

It has long been known that microradiography can be used for visual inspection of opaque objects, and the X-ray projection method for observing a perspective image by a projection method using parallel X-rays is industrial. It is used for medical and medical purposes. However, if the parallelism of X-rays is poor, the transmitted image will be blurred, so it is necessary to increase the parallelism for use in advanced measurement and exposure. In order to obtain a strictly parallel X-ray source, conventionally, as shown in FIG. 3, laser light excited by an excimer laser 31 is applied to a target 33 of a point X-ray source through a lens 32, and the X emitted from this target 33 is emitted. An expensive and huge device was required, such as parallelizing the lines with a concave mirror 34 formed of a multilayer film to obtain parallel X-rays. When an electron beam is narrowed down to obtain a point light source with an X-ray source using ordinary high-voltage accelerating electrons, the target is severely damaged due to heat generated by the local hitting of the electron, which is also expensive due to its cooling. A cooling system and a target rotation mechanism in a vacuum were required.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a collimator is integrally provided so as to make X-ray generation parallel from the beginning, and the apparatus is basically reduced in parallel. The purpose is to provide an X-ray source.

[0006]

In order to solve the above problems, the present invention fills the pores of a planar alumite film with metal and coats the metal with a metal to deposit electrons on the target surface. It is characterized by colliding, and its focus can be made very small with a small amount of power without using pores, so a small X-ray microscope can be realized using this, and the advantage of convenient inspection of invisible objects is there.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 (a) and 1 (b) are structural explanatory views of an X-ray source (X-ray generating tube) according to the present invention.
Is a tube stem, 3 is a target, 5 is a tube wall, 6 is a first DC power supply, 7 is a second DC power supply, 11 is a target film, 1
2 is an electrode, 13 is an insulating shim, 14 is a planar porous film, 2
3 is a substrate. The space surrounded by the tube stem 5 including the tube wall 5 and the cathode 1, the target 3, and the electrode 12 is maintained in a high vacuum like a vacuum tube.

FIG. 2 schematically shows the structure of the target 3 including the porous film 14. Reference numeral 21 is anodized alumite, 22 is a metal pillar, 23 is a substrate, 11 is a target film, and the pillar 22 has a diameter of several tens. The pillar 22 has a columnar shape of nm and the distance between the pillars 22 is several tens to several hundreds nm.

The target 3 has a planar shape which is arranged perpendicularly to the cathode 1 which is an electron generating source, and the vacuum side has a target film 1 made of a metal film such as copper or tungsten.
1, the other side is anodized alumite 21 and metal pillar 22
The target portion is fixed to the electrode 12 having a hole.

The porous film 14, which is a feature of the present invention, is obtained by anodizing aluminum from one side, enlarging the pores by etching, and further applying a metal to the pores for sealing treatment.

The operation of the present invention will be described with reference to FIGS. 1 (a) and 1 (b). A high electric field of several tens of kV is applied between the cathode 1 and the electrode 12 by the power source 6. Because of this, electrons are directly drawn from the cathode 1 into the vacuum. When viewed from the side of the electric field extracting electrode 12, the electron beam e ⁻ extracted from the electric field extracting electrode 12 flows into the target because the parts other than the target 3 are covered with the insulating shim 13. The electron beam e ⁻ extracted from the cathode 1 flows into the target 3. At this time, since the electron beam e ⁻ is accelerated at a high speed by the high electric field, it enters the inner core of the target atom and a part of the kinetic energy is absorbed. Are emitted from the target 3 as characteristic X-rays of atoms. The generation wavelength and efficiency of X-rays are proportional to the acceleration voltage of the electron beam e ⁻ and the atomic number of the target 3. Therefore, by using a thin metal for the target 3, the X-rays can be efficiently generated along the moving direction of the electron beam e ⁻ . Can occur.

X-rays are generated by collision of the accelerated electrons with the target 3, penetrate through the target 3 and are emitted isotropically. That is, the X-ray generation source has a size of a region where electrons collide. However, when penetrating the target film 11 and the porous film 14 forming the front and back,
As for the X-rays emitted from the surface of the target film 11, the components perpendicular to the film surface pass only through the alumite 21 portion, but the X-rays deviated from the normal direction of the film surface are absorbed because they pass through the metal pillars 22. As a result, only X-rays of the normal direction component are emitted from the target 3 and parallel X-rays are emitted.

Further, in the example of FIG. 1, the target 3 also serves as a partition between the inside and the outside that needs to be evacuated in order to accelerate electrons, and there is a possibility of absorbing X-rays in the X-ray radiation direction. X-rays can be extracted efficiently because there is no certain substance. Since the substrate 23 only needs to play a role as a base when aluminum is deposited on the substrate 23 for anodic oxidation and the subsequent metal plating is performed, any material that can be easily planarized and has low X-ray absorption may be used. Graphite,
A plastic such as polyimide may be used. Further, although the thin substrate 23 is used in the description of the present embodiment, aluminum is used to anodize to a predetermined thickness.
Of course, it may be removed by etching from the opposite side.

The target 3 generates heat when electrons are concentrated and collide, but the electrode 12 connected to the target 3 serves as a current path and also serves as a heat radiation path for heat generated. Further, in this embodiment, the X-rays are parallel regardless of the size of the target 3, so that the electron density colliding with the target 3 can be reduced and the influence of heat generation can be avoided.

Further, it is essential to concentrate the electron beam in a small area and collide with the target 3 in order to reduce the focus of the X-ray. However, even if the electrode 12 has a cone shape, the electron beam is positively applied in the structure. Unless an electron lens for converging on is used, the electron beam inevitably spreads according to the potential distribution, and the electron beam collides with the tube wall 5 and the momentum of the electron beam deviates from the linear distribution. If the tube is enlarged to avoid this, the vacuum degree is not maintained and the mechanical stability is deteriorated. Therefore, in this embodiment, the entire generating tube is made extremely small. Specifically, when the distance between the target 3 and the cathode 1 is within several tens of μm with respect to the target target 3 region of the μm order, the electrons extracted from the cathode 1 are hit against the target 3 without being extremely diffused. .
By making the size of the tube stem 2 several tens of times the size of the tube stem 2, it is possible to manufacture an X-ray generating tube having practically no problem.

It is well known that the X-rays can be efficiently generated by appropriately selecting the materials of the target film 11 and the pillars 22. For example, copper can be used for the target film 11 and iron can be used for the pillars 22 to form an X-ray microscope of about 1.5 angstroms. To obtain a shorter parallel X-ray source, tungsten can be used for the target film 11. Silver or the like may be used for the pillar 22.

As is apparent from the above description, it can be easily inferred that a simple X-ray collimator can be realized by filling the pores of anodized alumite 21 with a metal. Furthermore, wipe off the metal to be filled, and remove alumite 2
It is easy to consider that the pore 1 is an X-ray passage. For example, when a very long X-ray (several tens to several hundred angstroms) obtained by using carbon or silicon as a target material is targeted. It goes without saying that it will be fully practical.

[0019]

As described above, according to the present invention, the focal point can be made extremely small with a small amount of electric power without using a pore. Therefore, a small X-ray microscope can be realized by using this.
There is an advantage that inspection of invisible objects becomes convenient.

[Brief description of drawings]

FIG. 1A is a structural view showing an example of an X-ray generating tube according to the present invention, and FIG. 1B is an enlarged view showing an example of a target shown in FIG.

FIG. 2 is a schematic structural diagram showing an example of a target including a porous film according to the present invention.

FIG. 3 is a structural explanatory view showing a conventional parallel X-ray source.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cathode, 2 ... Tube stem, 3 ... Target, 5 ... Tube wall, 6 ... 1st DC power supply, 7 ... 2nd DC power supply, 11 ...
Target film, 12 ... Electrode, 13 ... Insulation shim, 14 ... Porous film, 21 ... Anodized alumite, 22 ... Metal pillar,
23 ... Substrate.

Front page continuation (72) Inventor Tetsuo Iijima 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. A parallel X-ray source, characterized in that the pores of a planar alumite film are filled with metal, and electrons are made to collide with a target surface formed by coating the metal on the pores.