KR101150778B1 - X-ray tube device of industrial CT equipment - Google Patents

Abstract

An X-ray tube apparatus of industrial CT equipment is disclosed. The disclosed X-ray tube device includes a tube housing loaded with insulating oil therein; A high voltage conductor (H / V conductor) in which a part is inserted into the tube housing, a part belongs to a vacuum part, and the other part is in contact with the insulating oil; A target base fixed to an inclined surface of the high voltage conductor belonging to the vacuum unit; And an anode target tightly fixed to an upper surface of the target base, wherein the target base is made of a material having a higher melting point than the anode target and a higher thermal conductivity than the high voltage conductor, and the high pressure conductor has an insulating oil along the inside thereof. Forming an inlet long groove, the heat absorption layer in contact with the bottom surface of the target base is coated on the inner peripheral surface of the long groove.

Description

X-ray tube device of industrial CT equipment {X-RAY TUBE APPARATUS OF INDUSTRIAL COMPUTED TOMOGRAPHY EQUIPMENT}

The present invention relates to an X-ray tube apparatus, and more particularly, to a closed X-ray tube apparatus employed in industrial computed tomography (CT) equipment for obtaining high resolution images.

In general, conventional X-ray equipment uses vertical X-ray beams to obtain vertical superimposed images of the subject (or human body), while CT equipment has a horizontal, vertical or arbitrary angle cross section with respect to the X-ray beam and the scan path of the detector. Get the video.

The CT device expresses the obtained image as a voxel with a material having a linear attenuation coefficient that is affected by the density of the material and the effective atom number during the slicing process.

On the other hand, CT equipment includes medical CT equipment for examining the inside of a human body, and industrial CT equipment for acquiring a high magnification image to observe fine parts such as a junction of a semiconductor at high resolution, compared to medical CT equipment.

Such conventional industrial CT equipment must satisfy the following conditions in order to obtain a high magnification image. First, the focal spot size at which the beam current emitted from the electrode is focused on the anode target must be small, and second, uniform X-ray dose and third, uniform spot point must be secured. .

In particular, in order to realize uniform X-ray dose, which is the second condition, the lifetime of the anode target acts as an important variable. Factors affecting the lifetime of the anode target include the size of the forcut spot and the tube current. The smaller the size of the four-cut spot, the higher the X-ray spatial resolution, so that high magnification images can be collected. However, the smaller the focal spot size, the higher the heat concentration as the number of electrons per unit area increases, so the lifespan is shortened as the target is exposed to high temperature. In addition, even with the same focal spot size, if the amount of power (tube current and tube voltage) increases, this also shortens the life of the target. As a result, the microclosed X-ray source had a limit in maintaining high focus and outputting high doses.

In addition, the material and cooling structure of the high-voltage conductor are important parameters to obtain a uniform spot point, which is the third condition. Referring to FIG. 1, in the conventional X-ray tube apparatus 100, X-rays are generated from the target 103 while the tube current generated from the electrode 105 is focused on the target 103. do. This heat is transferred from the target 103 to the high voltage conductor 101 and the high pressure conductor 101 absorbing the heat expands by a predetermined length in the vertical direction.

As a result, the target 103 fixedly installed on a part of the high pressure conductor 101 changes the position of the penetrating body 107 by the expansion of the high pressure conductor 101, and thus the position 108 of the X-ray transmissive image before the change. Is changed to the position 109 shifted to one side. As a result, as the position of the X-ray transmission image changes, the center position of the CT algorithm also changes. Therefore, according to the prior art, even if the X-ray tube apparatus having a high resolution detector and a small focal spot size of high quality, there is a problem that can not obtain a high quality image.

In order to solve the above problems, the present invention rapidly dissipates a lot of heat generated by the tube current focused on the anode target to efficiently cool the anode target and uniformly position the focal spot point by preventing the high voltage conductor from expanding. The object is to provide a sustainable X-ray tube apparatus.

The present invention to achieve the above object, the tube housing is filled with insulating oil therein; A high voltage conductor (H / V conductor) in which a part is inserted into the tube housing, a part belongs to a vacuum part, and the other part is in contact with the insulating oil; A target base fixed to an inclined surface of the high voltage conductor belonging to the vacuum unit; And an anode target tightly fixed to an upper surface of the target base, wherein the target base is made of a material having a higher melting point than the anode target and a higher thermal conductivity than the high voltage conductor, and the high pressure conductor has the insulating oil along the inside thereof. Forming an inlet long groove, the inner peripheral surface of the long groove provides an X-ray tube device characterized in that the heat absorption layer is in contact with the bottom surface of the target base.

The anode target may have a thin disk shape, and the target base may have a disk shape having an area larger than that of the target.

Preferably, the target is made of tungsten, molybdenum, copper, gold, and Re.W (renium tungsten), and the target base is made of diamond.

The high voltage conductor may be made of copper.

In addition, the high-voltage conductor may be made of a material having a thermal expansion coefficient smaller than or equal to the thermal expansion coefficient of the target, for example, diamond, ceramic, quartz, or glass.

In this case, the surfaces of the ceramics, quartz and glass are preferably coated with an electrically conductive material such as tungsten, copper, silver, or the like.

The heat absorption layer may be made of any one of diamond, copper, silver, and graphite.

The heat absorption layer may be formed through a chemical vapor deposition (CVD) or a sputtering process.

The tube housing may further include a heat dissipation member having a plurality of heat dissipation fins to dissipate heat transferred from the high voltage conductor to the insulating oil to the outside. In this case, it may further include a cooling fan installed on one side of the heat dissipation member forcibly cooling the heat dissipation member.

The insulation cover for supporting the high voltage conductor is connected to the high voltage conductor by a connection ring, and the connection ring preferably has a heat dissipation factor that can be bonded to the insulation cover. In this case, the insulating cover may be made of ceramic or glass, and the connecting ring may be made of a kovar alloy.

As described above, in the present invention, the anode target can be effectively cooled by absorbing a large amount of high heat generated in the anode target through the target base having a very high thermal conductivity and melting point. Accordingly, the anode target can prevent the portion corresponding to the focal spot point of the anode target from being damaged due to heat concentration when the X-ray tube apparatus is used for a long time, and can extend the life of the anode target.

In addition, the present invention can quickly dissipate heat generated from the anode target to the heat absorbing layer of the inner peripheral surface of the long groove through the target base, the heat present in the heat absorbing layer is absorbed by the insulating oil again can effectively cool the high pressure conductor. Accordingly, since the high pressure conductor applied to the present invention significantly reduces thermal expansion as compared with the related art, the change of the focal spot point can be minimized by suppressing the position change of the anode target to the maximum.

1 is a schematic view showing that the focal spot point is changed and the position of the X-ray transmission phase is changed as the high-pressure conductor of the conventional X-ray tube apparatus is expanded;
Figure 2 is a schematic cross-sectional view showing an X-ray tube device according to an embodiment of the present invention,
3 is an enlarged view showing part III shown in FIG. 2;
4 is a view seen from the IV direction shown in FIG.
5 shows an example in which the target base has a larger area than the anode target;
6 is a cross-sectional view showing an example in which an air-cooled cooling means is installed in the tube housing shown in FIG.
7 and 8 are cross-sectional views illustrating various examples in which water / cooling cooling means are installed in the tube housing illustrated in FIG. 2.

Hereinafter, with reference to the accompanying drawings will be described the configuration of the X-ray tube device according to an embodiment of the present invention.

2, the X-ray tube device according to an embodiment of the present invention is the tube housing 10, the electrode 20, the high pressure conductor 30, the anode target 40 and the target base 50 It includes.

The tube housing 10 has an insulating oil 14 loaded therein, and prevents the high voltage current generated from the high voltage conductor 30 from being transferred to the outside of the X-ray tube device 1 through the insulating oil 14. In addition, the insulating oil 14 also serves to cool the high voltage conductor 30 while being in contact with a portion of the high voltage conductor 30.

In addition, the tube housing 10 is provided with an insulating cover 11 inside the tube housing 10 to support the high-pressure conductor 30, a part of which is introduced into the tube housing 10. The insulation cover 11 is electrically insulated from the high voltage conductor 30 through the first connection ring 12, and insulates the tube housing 10 corresponding to the ground and the high voltage current flowing through the high voltage conductor 30. Such insulation cover 11 is preferably formed of glass or ceramic in order to maximize the insulation effect.

The first connection ring 12 has a coefficient of thermal expansion that can be bonded to the insulating cover 11, and a bar that can alleviate the impact due to thermal expansion generated between the insulating cover 11 and the high voltage conductor 30 ( Kovar) alloy. In this case, the high voltage conductor 30 is made of a material having a high thermal conductivity, for example, copper, silver, graphite or diamond.

In addition, the tube housing 10 has an opening 13 formed in the upper portion to allow the high voltage conductor 30 to pass therethrough, and the opening 13 is coupled to an outer cover 15 surrounding the upper side of the high pressure conductor 30. do.

The outer cover 15 is coupled to the insulating cover 11 through the second connection ring 17 at the bottom. In this case, the outer cover 15 surrounds the upper portion of the high-voltage conductor 30 disposed vertically, and the upper portion of the outer cover 15 has a window 15a through which X-rays radiated from the anode target 40 pass. do. The window 15a is preferably formed of beryllium to increase the transmittance of X-rays.

On the other hand, the insulating cover 11 and the outer cover 15 coupled to each other to form a vacuum portion 18 on the inside, such a vacuum portion 18 by maintaining a high vacuum state of less than 1 × 10E-6torr breakdown insulation It acts as a high strength insulator. In addition, the vacuum unit 18 is heat radiation from the high-voltage conductor 30 to the insulating cover 11 or the outer cover 15.

The electrode 20 is horizontally installed on one side of the outer cover 15 so as to be disposed at a right angle with respect to the high voltage conductor 30. This electrode 20 generates a tube current and focuses the tube current on the anode target 40.

The electrode 20 has the following configuration, that is, a cathode filament 21 for generating electrons by being heated by receiving power from the outside, and a grid for controlling the amount of electrons generated in the cathode filament 21 ( grid electrode 23, a focus electrode 25 for focusing electrons generated at the cathode filament 21 to the anode target 40, and an electrode cover 27, respectively. In this case, the electrode cover 27 includes a cathode filament 21, a grid electrode 23 and a focus electrode 25 on the inside thereof, and the inside of the electrode cover 27 maintains a vacuum state.

The high voltage conductor 30 has a substantially rod-like shape, and an inclined surface 31 in which the anode target 40 and the target base 50 are stacked and disposed on an upper end thereof is formed. The high voltage conductor 30 may be made of copper (Cu) having a relatively high thermal conductivity to enable absorption of heat from the target base 50 in direct contact. In this case, the material of the high-voltage conductor 30 is not limited to copper, but may be made of any material having a low coefficient of thermal expansion, for example, ceramic, quartz, glass, or diamond.

In this case, the surfaces of the ceramics, quartz and glass are preferably coated with an electrically conductive material such as tungsten, copper, silver, or the like.

In addition, the high voltage conductor 30 contacts the insulating oil 14 loaded in the tube housing 10 as the lower end connected to the high voltage electrode 33 is exposed to the outside of the insulating cover 11. Accordingly, the high pressure conductor 30 is cooled through contact with the insulating oil 14 which maintains a lower temperature than the high pressure conductor 30.

On the other hand, the high-voltage conductor 30 is described as being made of copper having a high thermal expansion as described above, but is not limited to this material having a thermal expansion coefficient less than or equal to the thermal expansion coefficient of the target 40, for example, a target ( It is also possible, of course, made of the same tungsten as the material of 40).

As such, when the high pressure conductor 30 is made of tungsten, the phenomenon in which the high pressure conductor 30 is thermally expanded can be greatly reduced as compared with the case of Cu, and thus the focal spot point of the anode target 40 can be prevented from being changed. Can be.

Furthermore, the high voltage conductor 30 forms a long groove 35 to allow the insulating oil 14 to flow in the longitudinal direction inwardly, thereby increasing the area in which the high pressure conductor 30 can be in contact with the insulating oil 14. Cooling efficiency of the conductor 30 can be improved.

In this case, the long groove 35 may be formed by coating a heat absorption layer 37 having a predetermined thickness on the inner circumferential surface through a chemical vapor deposition (CVD) or a sputtering process.

The heat absorbing layer 37 has a portion 37a in contact with the bottom surface of the target base 50. Accordingly, the heat absorbing layer 37 absorbs high heat from the target base 50 through the portion 37a of the heat absorbing layer 37. 37), the thermal shock applied to the anode target 40 can be greatly reduced.

The heat absorption layer 37 may be formed of any one of diamond, copper, silver, and graphite having high thermal conductivity.

The anode target 40 is formed in a disk shape having a thin thickness, for example, a thickness of 10 μm or less suitable for micro focus, and is placed on the target base 50 disposed on the inclined surface 31 of the high voltage conductor 30. It is fixed. The anode target 40 is formed of tungsten (W) having a high atomic number and melting point (atomic number: 75, melting point: 3450 ° C.) in consideration of the fact that the efficiency of X-rays increases as the atomic number of the target increases. . In this case, it is also possible to use any one of molybdenum, copper, gold, and Re.W (linium tungsten) in addition to tungsten.

3 and 4, the target base 50 is fixedly installed in contact with the inclined surface 31 of the high voltage conductor 30 and has a substantially disk shape. The target base 50 has a high thermal conductivity and a melting point higher than that of the anode target 40 so as to quickly absorb a large amount of heat generated when X-rays occur while the tube current is focused on the anode target 40. It is preferable to consist of diamond.

In this case, the target base 50 may be arranged in the vertical direction of the point where high heat is generated, that is, on the bottom surface of the anode target 40 (see FIG. 3) to increase the surface area of the heat concentration region. Accordingly, by rapidly dispersing the heat concentrated on the anode target 40 to increase the cooling efficiency of the anode target 40 it is possible to prevent shortening the life of the anode target 40 due to heat concentration.

In addition, as shown in FIG. 5, the target base 51 may have a larger diameter than the anode target 40, and in this case, the heat distribution area may be increased as compared with the case where the diameter of the anode target 40 is the same. The cooling efficiency of 40 can be further improved.

X-ray tube device 1 according to an embodiment of the present invention described above may be provided with a cooling means for cooling the insulating oil (14) charged inside the tube housing (10). In this case, the cooling means may be any one of an air-cooled cooling means and a water cooling / oil cooling cooling means.

First, referring to Figure 6, the air-cooled cooling means may be composed of a heat radiation member 71 and the cooling fan (73). The heat dissipation member 71 is installed on at least one side portion of the tube housing 10 and is made of a metal having high thermal conductivity, for example, Cu or Al.

The heat dissipation member 71 preferably includes a plurality of heat dissipation fins. However, the heat dissipation member 71 is not limited to this shape, of course, it is also possible to manufacture a heat pipe (not shown).

The cooling fan 73 is for forcedly discharging the heat absorbed by the heat dissipation member 71 to forcibly cool the heat dissipation member 71, and is disposed to be in contact with one side of the heat dissipation member 71.

In addition, referring to FIG. 7, the water-cooled cooling means installs a coolant circulation device 80 and a flow path 81 of a coolant (normal coolant material or cold water) so as to contact the side surface of the tube housing 10 to insulate the oil 14. Can be cooled. In this case, the flow path 81 has a normal pipe shape.

On the other hand, although not shown in the drawings, when the tube housing 10 as well as the side of the tube housing 10 is made of a cylinder, it is also provided that the flow path 81 to be continuously contacted in the spiral direction along the outer periphery of the tube housing 10 It is possible.

In the case of the water-cooled cooling means, as shown in FIG. 8, it is of course possible to install the heat dissipation member 71 between the side surfaces of the tube housing 10 and the pipe 81.

X-ray tube device according to an embodiment of the present invention configured as described above is a target base 50 having a very high thermal conductivity and melting point of a large amount of high heat generated by the tube current focused on the focal spot point of the small size of the anode target 40 The anode target 40 can be cooled by absorbing the same through the cavities. Accordingly, the anode target 40 prevents the portion corresponding to the focal spot point of the anode target 40 from being damaged due to heat concentration as the X-ray tube apparatus 1 is used for a long time, and of course, the anode target 40 ) Can extend the life of the.

In addition, the heat generated from the anode target 40 is quickly dispersed into the heat absorption layer 37 on the inner circumferential surface of the long groove 35 through the target base 50, and then to the insulating oil 14 in contact with the heat absorption layer 37 As it is sequentially absorbed, the high pressure conductor 30 may be effectively cooled. Through such a cooling structure, the high pressure conductor 30 can significantly suppress thermal expansion due to a significant reduction in thermal expansion as compared with the related art. Therefore, the change of the focal spot point set in the anode target 40 can be suppressed as much as possible.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

10: tube housing 11: insulation cover
14: insulating oil 15: outer cover
18: vacuum portion 20: electrode
30: high voltage conductor 35: long groove
37: heat absorbing layer 40: anode target
50: target base 71: heat dissipation member
73: cooling fan 80: refrigerant circulation device
81: refrigerant path

Claims (14)

A tube housing filled with insulating oil therein;
A high voltage conductor having a portion inserted into the tube housing, a portion belonging to a vacuum portion, and the remaining portion contacting the insulating oil;
A target base fixed to an inclined surface of the high voltage conductor belonging to the vacuum unit; And
And an anode target fixed to the upper surface of the target base.
The target base is made of a material having a higher melting point than the anode target and a higher thermal conductivity than the high voltage conductor,
The high voltage conductor forms a long groove into which the insulating oil flows along an inner side thereof, and a heat absorption layer is coated on an inner circumferential surface of the long groove to contact a bottom surface of the target base.
The target is made of any one of tungsten, molybdenum, copper, gold, Re.W (linium tungsten), the target base is made of diamond,
The high-pressure conductor is an X-ray tube device, characterized in that made of a material having a thermal expansion coefficient less than or equal to the thermal expansion coefficient of the target. The X-ray tube apparatus of claim 1, wherein the anode target has a disk shape of a thin film, and the target base has a disk shape having an area larger than that of the target. delete The X-ray tube apparatus according to claim 1, wherein the high pressure conductor is made of copper. delete The X-ray tube apparatus of claim 1, wherein the high pressure conductor is made of one of diamond, ceramic, quartz, and glass. 7. The X-ray tube apparatus according to claim 6, wherein the high pressure conductor is coated with a conductive material on a surface thereof. 8. An X-ray tube apparatus according to claim 7, wherein said energizable material is any one of tungsten, copper and silver. The X-ray tube apparatus of claim 1, wherein the heat absorption layer is made of one of diamond, copper, silver, and graphite. The X-ray tube apparatus of claim 9, wherein the heat absorbing layer is formed through a chemical vapor deposition (CVD) or a sputtering process. 10. The X-ray tube apparatus according to claim 9, wherein the tube housing further comprises a heat dissipation member having a plurality of heat dissipation fins for dissipating heat transferred from the high voltage conductor to the insulating oil to the outside. 12. The X-ray tube apparatus according to claim 11, wherein the heat dissipation member further includes a cooling fan installed at one side. According to claim 1, The insulating cover for supporting the high voltage conductor is connected to the high voltage conductor by a connecting ring,
The connection ring is an X-ray tube device, characterized in that it has a thermal expansion coefficient that can be bonded to the insulating cover. The material of claim 13, wherein the insulation cover is made of ceramic or glass.
X-ray tube device, characterized in that the material of the connection ring is a kovar (kovar) alloy.

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