KR20090009789A - X-ray tube and x-ray irradiator employing it - Google Patents

Abstract

An X-ray tube having a structure suitable for irradiating X-rays over a wide range, and an X-ray irradiator employing it. The X-ray tube (1) is provided, in a vacuum enclosure, with an electron source for radiating electrons and a target material generating X-rays in response to incidence of electrons from the electron source, wherein the vacuum enclosure is provided with an X-ray take-out window for taking out the X-rays generated from the target material to the outside. The X-ray take-out window is constituted of a plurality of window units (13A, 13B) including one or more through holes (13) provided in the vacuum enclosure and arranged in a plurality of, at least two, rows along the longitudinal direction of the vacuum enclosure, and the plurality of window units (13A, 13B) are arranged in zigzag along the longitudinal direction of the vacuum enclosure between the adjoining rows.

Description

TECHNICAL FIELD The present invention relates to an X-ray tube and an X-ray irradiator using the same,

The present invention relates to an X-ray tube for irradiating X-rays, and more particularly to an X-ray tube having a structure suitable for widely radiating X-rays and an X-ray irradiation apparatus using the same.

An X-ray tube is an apparatus for generating X-rays by generating electrons by using an electron source in a high-vacuum tube, and causing the electrons to enter the target. As such an X-ray tube, for example, there is an X-ray apparatus shown in the following (Patent Document 1). In this X-ray apparatus, the electron beam emitted from the planar cathode collides with the target planar anode, and X-rays generated from the planar anode are taken out through the take-out window provided on the side surface of the vacuum vessel.

Patent Document 1: JP-A-2003-288853

[PROBLEMS TO BE SOLVED BY THE INVENTION]

However, as described above, the X-ray tube having the structure in which the planar electron source is held in the case is large in the area of the X-ray irradiation area because the electron source and the target are enlarged. Here, in order to irradiate the X-rays over a wide range, it is necessary to enlarge the extraction window accompanied with enlargement of the electron source. However, if the extraction window is enlarged, the extraction window is liable to be damaged.

Therefore, in order to increase the intensity of the extraction window, it is also conceivable to divide and install the extraction window. However, in this case, there is a problem that the strength of the X-ray irradiated on the large-sized irradiated object tends to be uneven.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an X-ray tube capable of maintaining the strength of the apparatus even when the X-ray irradiation range is widened and realizing uniform X-ray irradiation.

MEANS FOR SOLVING THE PROBLEMS [

In order to solve the above problems, the X-ray tube of the present invention is characterized in that an electron source that emits electrons and a target that generates X-rays in accordance with incidence of electrons from the electron source are provided in a vacuum enclosure, Ray extraction window for extracting the X-ray generated from the X-ray extraction window to the outside, wherein the X-ray extraction window has the window unit including at least one window portion provided in the vacuum casing, The plurality of window units are arranged in a staggered arrangement in a predetermined direction between adjacent rows.

According to such an X-ray tube, X-rays are generated by electrons emitted from the electron source in the vacuum enclosure to enter the target, and the X-rays are taken out to the outside through the X-ray extraction window provided in the vacuum enclosure . By dividing the X-ray extraction window into a plurality of window portions, the intensity of the X-ray extraction window can be increased even if the entire X-ray extraction window is enlarged, and at the same time, the window unit having one or more window portions can be divided into two or more The irradiation intensity of the X-ray along the direction perpendicular to the predetermined direction can be made uniform throughout the entire X-ray irradiated region.

It is preferable that the window has a window material provided in a vacuum envelope so as to cover the through hole and the through hole formed in the vacuum envelope and the window material is preferably divided and arranged between the rows in which the window units are arranged. By providing such an X-ray extraction window, it is possible to reduce the area to be sealed for each window material, so that breakage of the window material covering the through hole can be prevented.

It is also preferable that the window member is divided and provided for each window unit in a predetermined direction. In this case, since the area sealed by each window member can be further reduced, breakage of the window member can be further prevented.

It is also preferable that the window portion is formed in a slit shape. With this configuration, the irradiation intensity of the X-ray along the predetermined direction can be more uniform.

It is also preferable that the window is formed in a circular shape. In this way, since the shape of the vacuum encapsulation region becomes circular, it is possible to further prevent breakage of the X-ray extraction window.

It is also preferable that the through hole is formed so as to extend toward the outside of the vacuum envelope, the window material is provided so as to cover the through hole from the inside of the vacuum envelope, and the target is provided inside the window. In this case, the X-rays generated from the target can be effectively taken out to the outside, and the possibility of breakage of the X-ray extraction window due to contact with the window or the like can be reduced (decreased) by arranging the window material inside the through hole .

Furthermore, it is preferable that the through hole is formed so as to become narrow toward the outside of the vacuum envelope, the window material is provided so as to cover the through hole from the outside of the vacuum envelope, and the target is provided inside the window. With this configuration, the efficiency with which electrons are incident on the target can be increased.

Furthermore, it is also preferable that the vacuum envelope is formed in a long shape, and that a plurality of window units are arranged along the longitudinal direction of the vacuum envelope. With this configuration, the X-ray can be irradiated with a larger width.

Alternatively, the X-ray irradiating apparatus of the present invention includes the above-described X-ray tube, and a guide portion for relatively moving the X-ray tube and the irradiated body along the direction crossing the predetermined direction in front of the X-ray extraction window. According to such an X-ray irradiator, X-rays can be more uniformly irradiated to an object having a large area.

EFFECTS OF THE INVENTION [

According to the present invention, it is possible to provide an X-ray tube that can maintain the strength of the apparatus even when the X-ray irradiation range is widened and realizes uniform X-ray irradiation.

1 is a plan view of an X-ray tube which is a preferred embodiment of the present invention.

Fig. 2 is a plan view showing a state in which the upper face plate (upper face plate) of the X-ray tube of Fig. 1 is removed.

3 is a cross-sectional view taken along line III-III of the X-ray tube of FIG.

4 is a cross-sectional view taken along the line IV-IV of the X-ray tube of FIG.

5 is a perspective view of a static electricity eliminating apparatus using the X-ray tube of FIG.

6 is a plan view of an X-ray tube which is a modification of the present invention.

Fig. 7 is a cross-sectional view taken along line VII-VII of the X-ray tube of Fig. 6;

8 is a plan view of an upper face plate in a modification of the present invention.

9 is a plan view of an upper face plate in a modification of the present invention.

10 is a plan view of an upper face plate in a modified example of the present invention.

11 is a plan view of an upper face plate in a modified example of the present invention.

<Explanation of Symbols>

1, 21 ... X-ray tube, 5 ... Vacuum envelope, 8a, 8b, 8c ... Electronic circle, 13, 33 ... Through holes (window portions), 13A, 13B, 33A, 33B, 43, 53, 63, 73 ... Window units, 14, 34 ... Silicon thin film (window), 15, 35 ... Target material, 101 ... Electrostatic charge eliminator (X-ray irradiator), 110 ... Vinyl film (living thing), 120, 121 ... Roller (guide part).

BEST MODE FOR CARRYING OUT THE INVENTION [

Hereinafter, preferred embodiments of the X-ray tube according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or equivalent portions are denoted by the same reference numerals, and redundant explanations are omitted. In addition, each drawing is prepared for explanatory purposes, and is specifically described to emphasize the target area. Therefore, the dimensional ratios of the respective members in the drawings do not necessarily coincide with actual ones.

Fig. 1 is a plan view of an X-ray tube 1 according to a preferred embodiment of the present invention. Fig. 2 is a plan view showing a state in which an X- Fig. 4 is a cross-sectional view taken along the line IV-IV in Fig. 1. Fig.

As shown in this figure, the X-ray tube 1 has an upper face plate 2 and a lower face plate 3 which are made of an insulating member such as a flat plate glass having a long length and a rectangular pillar Shaped sidewall 4 of the vacuum envelope 5. The vacuum envelope 5 of Fig. The upper face plate 2 and the lower face plate 3 and the side wall 4 are formed by glass and the upper face plate 2 and the lower face plate 3 are formed by flit glass or the like at the open end of the side wall 4 And the inside of the vacuum envelope 5 is kept airtight by being sealed.

On the inner surface 3a of the lower face plate 3 constituting a part of the vacuum envelope 5 are formed band-shaped metal films 7a, 7b (6b, 6c) coated with carbon-based electron emitting materials 6a, 6b, 8c, 8c constituted by the electron emitting portions 8a, 8b, 8c and 7c (see Figs. 2 and 4). The electron emitting materials 6a, 6b and 6c are coated on the upper surfaces of the electron sources 8a, 8b and 8c excluding the both ends of the metal films 7a, 7b and 7c. The metal films 7a, 7b and 7c are respectively provided with external connection pins 9a and 9b which are provided as a pin to penetrate the outside from the vacuum envelope 5 as external pins for setting the voltages of the metal films 7a, And 9c are electrically connected to each other.

Here, the carbon-based electron emission materials 6a, 6b and 6c may be carbon nanotubes, carbon nanowalls, carbon nanofibers, diamond, diamond like carbon, And is a so-called field emission type electron emission material having a property of emitting electrons to the outside by the action of an electric field. As a method of coating the carbon-based electron emitting material on the metal films 7a, 7b, and 7c, a CVD method, a spray method, a printing method, or the like can be used.

These electron sources 8a, 8b and 8c are respectively arranged in three straight groove portions 16a, 16b and 16c formed by the side wall 4 and the inner surface 3a (Fig. 4). That is, in the side wall 4, the groove portions 16a, 16b, 16c are formed along the longitudinal direction of the lower face plate 3 by the three slits and the inner face 3a which are parallel to each other penetrating toward the lower face plate 3, And the metal films 7a, 7b and 7c are formed on the inner surface 3a as the bottom surfaces of the trenches 16a, 16b and 16c, respectively.

On the inner surface 4a of the side wall 4 where the grooves 16a, 16b and 16c are sandwiched therebetween, lead electrodes 11, which are strip-shaped metal films, are arranged in parallel with the electron sources 8a, 8b and 8c A plurality is provided. The drawing electrode 11 is divided and arranged so as to place the electron sources 8a, 8b and 8c at both sides thereof and further divided into two along the longitudinal direction of the electron sources 8a, 8b and 8c. An external connection pin 12 is connected to the extraction electrode 11 for each pair of electrodes provided with the electron sources 8a, 8b and 8c interposed therebetween.

The upper face plate 2 is provided with a plurality of slit-shaped through holes 13 at positions opposed to the electron sources 8a, 8b and 8c to function as an X-ray extraction window for taking out the X- (Fig. 1). The through hole 13 is formed in a trapezoidal cross section so as to narrow from the opening on the inner side of the vacuum side of the upper face plate 2 toward the opening on the outer side (FIG. 4).

These through holes 13 are arranged at equal intervals in a straight line in each column so as to be three columns in the longitudinal direction (predetermined direction) opposite to the respective electron sources 8a, 8b and 8c Respectively. As a result, a window unit 13A composed of two adjacent through holes 13 in the arrangement direction and a window unit 13B composed of one through hole 13 are formed. Two window units 13A are arranged so as to sandwich one window unit 13B in the rows at opposite ends to the electron sources 8a and 8c and two windows 13B are arranged in the central row facing the electron source 8b And window units 13A are disposed adjacent to each other. The window units 13A and 13B are arranged in a staggered arrangement along the longitudinal direction of the electron sources 8a, 8b and 8c between adjoining rows. More specifically, the electron source 8a 8b and 8c along the longitudinal direction of the electron sources 8a, 8b and 8c as viewed in a direction perpendicular to the arrangement direction of the window units 13A and 13B along the longitudinal direction of the window units 13A and 13B (Or the window unit 13B) of the column adjacent to the predetermined column at a position corresponding to the boundary between the window units 13A and 13B (or between the window units 13A) ) On both sides thereof. That is, the boundaries of consecutive window units in a predetermined row are arranged differently from each other so that they do not coincide with the boundaries of consecutive window units in adjacent columns. The through holes 13 in the window units 13A and 13B are formed so as to have the same arrangement as the window units 13A and 13B.

A silicon thin film 14 as a window member divided for each of the window units 13A and 13B is bonded to the outer surface of the upper face plate 2 by anodic bonding so as to cover the through hole 13. The silicon thin film 14, And the through hole 13 constitute a window portion that transmits X-rays to the outside. That is, the silicon thin film 14 is divided between the rows in which the window portions are arranged, and is also divided in the arrangement direction. As the window material, a material having other X-ray transmissivity such as beryllium may be used in addition to silicon. The presence of the silicon thin film 14 realizes hermetic sealing inside the vacuum envelope 5.

A target material 15 such as tungsten is formed by vapor deposition on the inner side of the silicon thin film 14, that is, the portion exposed from the through hole 13 on the vacuum side (FIG. 4). This target material 15 has a property of generating X-rays in accordance with the incidence of electrons from the electron sources 8a, 8b and 8c. A conductive member such as tungsten is also deposited on the vacuum side of the upper face plate 2, including the inner wall of the through hole 13. The electrons from the electron source 8 are also incident on the upper face plate 2 which is an insulating member, so that the upper face plate 2 is electrified and influences the electric field formed in the vacuum enclosure 5 in some cases. Therefore, by covering the electron incident side with the conductive member, charging is prevented. Further, in the present embodiment, it is formed integrally with the target material 15 by vapor deposition. The supply of the voltage to the target material 15 is also performed through the conductive member which is in contact with the external connection pin 17 provided outside the vacuum enclosure 5 through the outside.

In the above-described X-ray tube 1, electrons emitted from the electron sources 8a, 8b and 8c in the vacuum envelope 5 enter the target material 15 to generate X-rays, And is taken out to the outside through the X-ray extraction window provided in the vacuum envelope 5. This X-ray extraction window is formed by arranging the window units 13A, 13B having the through holes 13 in two or more rows in the zigzag arrangement along the longitudinal direction of the upper face plate 2, The holding area of the silicon thin film 14 in the window unit can be increased while maintaining the entire area of the entire X-ray extraction window by dividing the silicon thin film 14 into a plurality of regions in the through hole 13. As a result, It is possible to improve the strength and durability of the X-ray extraction window covered with the X-ray tube 14.

It is also possible to uniformize the irradiation intensity of the X-ray over the direction perpendicular to the longitudinal direction of the vacuum envelope 5 to the entire X-ray irradiated region and to make the irradiated object parallel to the surface of the X- X-rays can be uniformly irradiated to the entire surface of the object 5 having a large area without causing irregularity of irradiation. Particularly, in the case of irradiating X-rays with the object to be irradiated close to the X-ray tube, the directivity of the X-rays increases, so that the effect of uniforming the irradiation intensity by using the X-ray tube 1 is large.

The silicon thin film 14 is divided and provided between the rows in which the window units 13A and 13B are arranged and is also divided in the longitudinal direction of the vacuum envelope 5 as well. As a result, the area to be sealed for each silicon thin film 14 can be made small, so that the force applied to the silicon thin film 14 is also small. Thus, the silicon thin film 14 as a window covering the through- Can be prevented from being damaged. As the area of the silicon thin film 14 becomes larger, it tends to be difficult to obtain a uniform silicon thin film 14. However, if the area is reduced by the division, . That is, since the manufacturing efficiency is improved when the silicon thin film 14 is made of a silicon wafer or the like, the X-ray extraction window can be easily produced.

Since the through hole 13 is formed so as to be narrowed toward the outside of the vacuum envelope 5, electrons emitted from the electron sources 8a, 8b and 8c can efficiently enter the target material 15 In addition, since the silicon thin film 14 is provided on the outer surface of the upper face plate 2, the X-rays extracted from the silicon thin film 14 can be directly irradiated without being absorbed by the upper face plate 2, X-rays can be irradiated.

Next, the configuration of the static electricity eliminating apparatus 101 which is an X-ray irradiating apparatus using the X-ray tube 1 will be described. 5 is a perspective view showing a configuration of the electrostatic static removers 101. Fig. As shown in the same figure, the electrostatic static eliminator 101 includes rollers 120 and 121, which are guide members for advancing a strip-shaped vinyl film (prepared article) 110 in the longitudinal direction, An X-ray tube 1 and an X-ray tube 1 are arranged so that the advancing direction of the vinyl film 110 is perpendicular to the longitudinal direction of the vacuum envelope 5 and the X-ray tube 1 and the vinyl film And an X-ray shielding cabinet 140 for covering the X-ray irradiated portion of the X-ray shielding (shielding) 110. The inside of the X-ray shielding cabinet 140 is filled with air or gas.

In such an electrostatic static eliminator 101, X-ray emitted from the X-ray tube 1 by the power supply from the power supply device 150 passes through the vinyl film 110 ). Air or the like in contact with the upper surface of the vinyl film 110 is ionized by X-ray irradiation, and is bonded to the charge charged on the upper surface of the vinyl film 110. Therefore, the upper surface of the vinyl film 110 is discharged. X-rays reaching the upper surface of the vinyl film 110 pass through the vinyl film 110 to ionize the air and the like in contact with the back surface of the vinyl film 110. Electrons generated by ionization are combined with charges charged on the back surface of the vinyl film 110, and the back surface of the vinyl film 110 is also discharged. By arranging the X-ray tube 1 so as to cover the range through which the vinyl film 110 passes, it is possible to more uniformly irradiate the X-ray without uniformity of irradiation in an object such as a vinyl film having a large area, I can extinguish it. In particular, the X-ray tube 1 is arranged so that the column of the window unit is vertically aligned with respect to the traveling direction of the workpiece. The X-ray tube 1 is arranged such that the window units constituting the X-ray extraction window are arranged in a staggered arrangement. Therefore, with regard to the boundary portion between consecutive window units in the window unit for irradiating X- Then, the window unit of the column for irradiating X-rays to the irradiated object can be surely irradiated, so that irradiation and elimination can be performed without fail even if the area is large.

The present invention is not limited to the above-described embodiments. For example, as the shape of the window provided on the upper face plate 2 of the X-ray tube 1, various shapes can be adopted.

Fig. 6 is a plan view of the X-ray tube 21, which is a modified example of the present invention, and Fig. 7 is a sectional view taken along line VII-VII of the X-ray tube 21 in Fig. A window unit 33A including one through hole 33 and a window unit 33B including two through holes 33 are provided on the upper face plate 2 in the same manner as the X- In a zigzag arrangement in three rows along the longitudinal direction of the frame. The through holes 33 are formed in a trapezoidal cross section so as to be widened from the opening on the inner side of the vacuum side of the upper face plate 2 toward the opening on the outer side (Fig. 7). The silicon thin film 34 as a window is bonded along the inner surface of the upper face plate 2 so as to cover the through hole 33 from the inside (vacuum side), and the inner face of the silicon thin film 34, A target material 35 is formed on almost the entire surface on the surfaces facing the electron sources 8a, 8b, 8c.

In such an X-ray tube 21, since the silicon thin film 34 is disposed deeply from the outer surface of the upper face plate 2, breakage of the silicon thin film 34 due to external factors such as contact can be prevented At the same time, since the bonding portion of the silicon thin film 34 with the upper face plate 2 is not exposed to the atmosphere, deterioration of the bonding portion due to external factors is small.

The arrangement of the through holes in the individual window units of the X-ray extraction window can be variously arranged. Specifically, as in the case of the window unit 43 shown in Fig. 8, a plurality of through holes formed in a circular shape are formed so as to be lined up in one row, and window units and through holes are arranged in a zigzag arrangement between adjacent rows of the window units 43 . In this case, since the contact between the edge of the through hole and the window member has a circular shape, the dispersion of the force at the contact portion tends to be uniform, and the window member is hard to break. In addition, as in the case of the window unit 53 shown in Fig. 9, a plurality of through holes formed in a circular shape may be arranged in two rows, and two rows may be gathered to form one row as a window unit. In this case, it is possible to arrange the through hole and the portion supporting the window material in a balanced manner in the window unit. In addition, like the window unit 63 shown in Fig. 10, the through holes themselves may be arranged in a zigzag arrangement in the window unit 63. [ In this case, even in the window unit, uniform X-ray irradiation becomes possible. Further, as in the case of the window unit 73 shown in Fig. 11, through holes formed in a slit shape may be formed so as to be aligned in two rows, and two rows may be arranged as one row as a window unit. In this case, in the window unit, the through hole and the portion for supporting the window member can be arranged in a balanced manner, and the uniformity of X-ray irradiation in the longitudinal direction of the slit-shaped through hole is also high.

In addition, a window unit may be provided for each through hole.

In the X-ray irradiating apparatus, the guide portion is not limited to the means for moving the object to be irradiated, and may be a means for moving the X-ray tube.

The member constituting the vacuum envelope 5 is not limited to an insulating material. For example, a conductive member may be used for the upper face plate 2.

The conductive member deposited on the vacuum side of the upper face plate 2 is not limited to the case of being formed integrally with the target material but may be made of a conductive material different from the target material such as aluminum or ITO Oxide) or the like.

As described above, the present invention is applicable to an X-ray tube that irradiates X-rays, and particularly to an X-ray tube having a structure suitable for widely radiating X-rays and an X-ray irradiation apparatus using the same.

Claims (9)

A target for generating X-rays in accordance with the incidence of electrons from the electron source is provided in a vacuum enclosure and an X-ray generated from the target is irradiated with an electron beam, An X-ray tube having an X-ray takeout window for taking out the sample to the outside, Wherein the X-ray extraction window is formed by arranging a plurality of window units in at least two rows along a predetermined direction, the window units including at least one window portion provided in the vacuum chamber, Wherein the plurality of window units are arranged in a staggered arrangement in the predetermined direction between adjacent rows. The method according to claim 1, Wherein the window has a through hole formed in the vacuum enclosure and a window formed in the vacuum enclosure so as to cover the through hole, Wherein the window member is divided and provided between the rows in which the window units are arranged. The method of claim 2, Wherein the window member is divided for each window unit in the predetermined direction. The method according to any one of claims 2 to 3, Wherein the through hole is formed to be widened toward the outside of the vacuum enclosure, Wherein the window member is provided so as to cover the through hole from the inside of the vacuum enclosure, Wherein the target is provided inside the window member. The method according to any one of claims 2 to 3, The through hole is formed so as to be narrowed toward the outside of the vacuum envelope, The window member is installed so as to cover the through hole from the outside of the vacuum enclosure, Wherein the target is provided inside the window member. 6. The method according to any one of claims 1 to 5, And the window is formed in a slit shape. 6. The method according to any one of claims 1 to 5, And the window portion is formed in a circular shape. The method according to any one of claims 1 to 7, The vacuum envelope is formed in a long shape, And the plurality of window units are arranged along the longitudinal direction of the vacuum enclosure. An X-ray tube according to any one of claims 1 to 8, And a guide portion for relatively moving the X-ray tube and the irradiated object along a direction crossing the predetermined direction in front of the X-ray extraction window.

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