JP2001276042A - Cathode scanning type x-ray generator and x-ray ct scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a very high-speed CT scanner reducing the scanning time of an X-ray CT scanner remarkably and a cathode scanning type X-ray generator for realizing the scanning time reduction. SOLUTION: The very high-speed scanning type X-ray CT scanner and the cathode scanning type X-ray generator for realizing this have a doughnut-shaped vacuum vessel VV, a cathode-side rotator assembly AR, an electronic gun assembly EG, a cathode for discharging electron, and an annular cathode power supply mechanism. Then, while supplying the power to the cathode, the scanner and the generator make the cathode orbit around an examinee body to make an accelerated electronic beam incident on the surface of an annular X-ray target TG to generate X-rays orbiting at high speed. The cathode-side rotator assembly is freely rotatably supported by a bearing mechanism OGB consisting of a hydrodynamic slide bearing lubricated by metal liquid lubricant. The hydrodynamic slide bearing is provided with a liquid metallic lubricant absorbing mechanism in the middle of the opening part of a bearing and a vacuum space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode scan type X-ray generator for an X-ray CT scanner which is small in size and emits X-rays from an X-ray orbiting at a high speed and can perform ultra-high-speed scanning. And an X-ray CT scanner capable of performing ultra-high-speed scanning using the same. By limiting the rotating part for orbiting the X-ray focus to small parts in the vacuum vessel, the X-ray focus can be stabilized around the specimen at high speed without a mechanical rotation mechanism in the atmosphere. The present invention provides a small-sized X-ray CT scanner capable of obtaining a three-dimensional image by instantaneously photographing a subject by orbiting the subject. A cathode is circulated in a vacuum space in a vacuum vessel using a dynamic pressure sliding bearing using a liquid metal as a lubricant, and the cathode circulating in the vacuum vessel is energized from outside the vacuum vessel.

[0002]

2. Description of the Related Art A conventional X-ray CT scanner will be described with reference to FIG. Conventional X
The line CT scanner includes a fixed base 1001 and a bearing 1003.
And a rotating gantry 1002 that rotates through the. The rotating gantry 1002 is rotated in the air by a rotation driving mechanism 1009 controlled using a controller 1008. An X-ray tube 1004 for generating X-rays, a high-voltage power supply (not shown) for supplying a high voltage thereto, a detector 1006 for receiving X-rays, and other electronic circuits 10
07 and the like are attached to the rotating frame 1002. A signal of an electronic circuit attached to the rotating gantry 1002 is transmitted to the fixed gantry 1001 by a slip ring (not shown). For this reason, the sum of the mass of the components attached to the rotating frame 1002 increases, and when the scan speed of the X-ray CT scanner is increased, a large centrifugal force acts.
The parts and the rotating frame 10 attached to the rotating frame 1002
02 itself cannot withstand excessive stress, and thus has a disadvantage that the scanning speed cannot be increased.

[0003] X-rays used in conventional X-ray CT scanners
The wire tube 1004 is a disk-shaped X-ray target having a diameter of about 10 cm and 3,000 rpm in a cylindrical vacuum vessel.
The X-ray is rotated at a high speed of about m, and collides with electrons emitted from the cathode of the electron gun assembly to emit X-rays 1005 in one direction. The entire structure is cylindrical.
An X-ray tube for an X-ray CT scanner, which needs to generate a large amount of X-rays, requires a cooler, and the sum of both masses is 1
The rotation frame 1002 for attaching and rotating it in the air becomes large, and the entire X-ray CT scanner becomes large, which is not only inconvenient to handle, but also requires a large installation space. And the operating costs were large. Further, in recent years, as the use of X-ray CT scanners has expanded, there has been a demand for instantaneous observation of blood and a contrast agent. In order to respond to this, it is necessary to rotate the X-ray tube 1004 around the subject at a high speed. The highest orbiting speed so far is 2r
ps, which is considered the limit. on the one hand,
There is a demand to increase the X-ray dose to enhance the image quality and enhance the diagnostic performance, and it is necessary to increase the size and mass of the conventional X-ray tube 1004. Simultaneously satisfying these conflicting requirements has been impossible with an X-ray CT scanner having a conventional structure.

On the other hand, an X-ray CT scanner of the electronic scan type has been developed in the past in order to increase the scanning speed. This involves taking out electrons from an electron gun assembly fixed at the bottom of a vacuum container in the shape of a thermos bottle placed on its side, and controlling the position of the electrons electromagnetically while running the electrons about 100 cm in the vacuum container. After orbiting around the subject,
These electrons are made incident on an arc-shaped X-ray target to extract X-rays that make a half turn. In this structure,
High-speed scanning with a scan time of about 0.1 second is possible, but the image quality is poor due to the inability to obtain a sufficient amount of X-rays, the X-ray focus is too large, Are difficult to maintain, the whole device is large and difficult to handle, and it is expensive, and is used only for special applications.

[0005]

The problem to be solved is that the scan time of the X-ray CT scanner is greatly reduced to eliminate motion artifacts and to provide a sufficient level of X-ray dose in imaging a fast moving subject. An object of the present invention is to provide an X-ray CT scanner which can obtain a high-quality image with less photon noise by securing the X-ray CT scanner, and which is small in size and easy to handle. Particularly, in order to realize this, a cathode scan type X-ray generator and a cathode scan type X-ray generator capable of stably supplying a high voltage and a power for heating a cathode to an electron gun rotating in a vacuum from the outside of a vacuum vessel were used. X-ray CT
To provide a scanner.

[0006]

SUMMARY OF THE INVENTION In the present invention, all rotating parts of an X-ray CT scanner are mounted in a donut-shaped vacuum vessel to minimize the size of the rotating parts, eliminating the need for mechanical rotating parts in air. By doing so, an X-ray CT scanner capable of ultra-high-speed scanning is realized. The vacuum container is formed in a donut shape, and the subject is placed on a bed in the atmosphere near the central axis of the vacuum container. Electrons are emitted from the cathode of the electron gun assembly that circulates in the vacuum vessel, and accelerated electrons collide with the annular X-ray target mounted in the vacuum vessel in opposition to the orbit of the cathode to generate X-rays. generate. The generated X-ray passes through an X-ray emission window provided on the small-diameter wall of the vacuum vessel, and is applied to the subject in the atmosphere.
The X-rays that have passed through the subject are detected by an annular X-ray detector arranged in the atmosphere coaxially with the vacuum vessel, reconstructed into a tomographic image by a computer, and displayed on a display device. The rotating part for rotating the X-ray focal point in the vacuum vessel is limited to a lightweight electron gun assembly, etc., and its volume is small, and it is almost symmetrical as a whole. Even when rotating, the stress applied to the rotating body can be sufficiently reduced, and stable high-speed rotation can be continued. Further, since about three electron gun assemblies are attached to the same cathode side rotating body assembly, high-speed scanning with a scan time of about 0.03 seconds can be performed.

An X-ray CT scanner of the type in which an electron gun is rotated inside a donut-shaped vacuum vessel has been proposed in the past, but has not been realized so far. One of the reasons is that no reliable means has been found to stably supply high voltage and electric power for heating the cathode to the cathode of an electron gun assembly rotating in a vacuum from outside the vacuum vessel. It is. In the present invention, as a cathode power supply mechanism capable of supplying power to the cathode with high reliability in a vacuum, a power supply mechanism using an annular dynamic pressure sliding bearing using a metal that is liquid at normal temperature as a lubricant is adopted. Since the rotating part of the power supply mechanism is rotated in a vacuum in a state of floating with the liquid metal lubricant, electricity is supplied between the rotating part and the fixed part through the liquid metal lubricant, A stable power supply with little loss can be provided because of no abrasion and good conductivity of the liquid metal lubricant.

When the rotating part of the cathode power supply mechanism is rotating, the liquid metal lubricant is actuated by the suction action of the bearing groove provided on the surface of the hydrodynamic sliding bearing provided between the rotating part and the fixed part. Is trapped inside the bearing. Generally, when the rotating part of the hydrodynamic sliding bearing stops rotating, the leakage of the liquid metal lubricant is prevented by the surface tension of the liquid metal lubricant generated at the opening at the end of the bearing. However, in the X-ray CT scanner of the present invention, the center axis of rotation of the cathode feeding mechanism is substantially horizontal, and the bearing has a large diameter of about 120 cm, so that the height difference of the opening of the bearing is large and the opening of the bearing is large. The portion located vertically below receives a large static pressure due to gravitational acceleration. The size of the gap at the opening of the bearing is reduced as it is located vertically downward so that the pressure effect of the surface tension at the opening of the bearing overcomes this static pressure, and the pressure effect of the surface tension at any height is reduced. It is preferable that the pressure is higher than the static pressure of the liquid metal lubricant. As one of the means for easily realizing this, the rotating portion of the cathode power supply mechanism is mounted inside the fixed portion of the cathode power supply mechanism. Since the rotation center axis b is in the horizontal direction, the size of the gap in the vertically lower opening is always smaller than that in the vertically upper direction due to the influence of the gravitational acceleration. For this reason, the surface tension increases as it is located vertically downward, so that the liquid metal lubricant is prevented from leaking to the outside, and stable operation is guaranteed.

The bearing surface constituting the cathode power supply mechanism is thermally coupled to the vacuum vessel through an insulator having a high thermal conductivity, and the vacuum vessel is forcibly cooled from the outside, thus constituting the cathode power supply mechanism. Despite generating heat in the bearing part,
The temperature rise of the bearing surface is suppressed, the influence of thermal expansion is small, and stable operation can be continued for a long time. Further, in order to reduce deformation due to thermal expansion, a stress absorbing mechanism is provided to reduce non-axially symmetric deformation of the bearing portion, thereby improving mechanical accuracy. Although a plurality of cathode power supply mechanisms are attached, a rotational force transmitting mechanism having elasticity is provided so that these rotation centers may be shifted.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cathode scan type X-ray generator is wrapped in a donut-shaped vacuum vessel, and the vacuum vessel is installed so that its central axis is substantially horizontal. A subject (human body) is placed in the atmosphere, and the vacuum container is arranged so as to surround the subject. The vacuum container is fixed without rotating, and the angle with the subject and the position in the horizontal direction can be changed. X-rays are generated toward the subject while moving the X-ray focus so that the X-ray focal point orbits around the subject inside the vacuum vessel. An X-ray CT scanner that does not have a rotating mechanism in the atmosphere is realized using the orbiting X-rays. An X-ray scanner capable of performing ultra-high-speed scanning and obtaining a large output, which cannot be realized with an X-ray CT scanner having a conventional structure.
A cathode scan type X-ray generator for an X-ray CT scanner and an ultra-high-speed X-ray CT scanner using the same have been realized with a simple structure at low cost and with high reliability.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cathode scan type X-ray generator according to one embodiment of the present invention and an X-ray CT scanner using the same will be described below with reference to the drawings. FIG. 2A is a schematic sectional view of the entire structure of a cathode scan type X-ray generator of the present invention and an X-ray CT scanner using the same, and FIG. 2B is a cathode scan type of the present invention. FIG. 3 is a schematic diagram of an entire structure of an X-ray generator and an X-ray CT scanner using the same, as viewed in a direction from C ′ to C in FIG. FIG. 3 is an enlarged view of FIG. 2 (A), and FIG. 4 is an enlarged view of a cross section of a part of the cathode scan type X-ray generator according to the present invention which is located vertically above at a certain moment. 2 shows an enlarged cross-section of a part of the cathode portion in a state positioned vertically above. The same parts have the same symbols. FIG. 5 is an enlarged sectional view of a part of a cathode power supply mechanism SL1, which is a main part of the cathode scan type X-ray generator of the present invention. FIG. 6 is a principle diagram schematically showing the principle by further enlarging a part of FIG. 5 which is a part of the main part.

As shown in FIG. 2 or FIG. 3, the donut-shaped vacuum vessel VV is installed so that its central axis is substantially horizontal, and is always evacuated to a high vacuum state from an exhaust port VC by a vacuum pump (not shown). ing. As shown in FIG. 3 or FIG. 4, there is a cylindrical cathode-side rotating body assembly CR in a vacuum space inside the vacuum vessel VV. The cathode-side rotating body assembly CR uses a liquid metal, which is liquid at room temperature, with a lubricant. The bearings are rotatably supported in a vacuum by a bearing mechanism CBG comprising a dynamic pressure sliding bearing, and their central axes coincide with CC '. As shown by F1, F2, and F3 in FIG. 2B, three electron gun assemblies EG are attached to the cathode side rotating body assembly CR so as to be separated in the circumferential direction. As shown in FIGS. 3 and 4, a cylindrical rotor RT made of copper is provided on the cathode side rotating body assembly CR.
2 is mounted coaxially, and a magnetic path cylinder MT2 made of a magnetic material is mounted coaxially with this. FIG.
As shown in (B), three arc-shaped stators LM2 are attached along the vacuum vessel wall outside the vacuum vessel VV in a state facing the rotor RT2. The rotor RT2 is disposed between the magnetic path cylinder MT2 and the stator LM2. The rotor RT2 receives a rotational torque from the stator LM2 through the wall made of the non-magnetic material of the vacuum vessel VV and receives a rotational torque, so that the cathode side rotating body assembly CR rotates. Cathode side rotating body assembly C
R is electrically and thermally coupled to the vacuum vessel VV through a liquid metal lubricant in a bearing mechanism CBG comprising a dynamic pressure sliding bearing.

As shown in FIG. 4, a cathode 1 for emitting thermoelectrons 2 is attached to the tip of the electron gun assembly EG. An annular X-ray target TG is attached to face the orbit of the cathode 1. As shown in FIG. 3, the X-ray target TG is a cylindrical anode side rotating body assembly A
It is mechanically coupled to R. The anode side rotating body assembly AR is rotatably attached to a part of the vacuum vessel VV via a bearing mechanism ABG including a dynamic pressure sliding bearing using liquid metal which is liquid at room temperature as a lubricant. Anode rotating body assembly AR
Is equipped with a rotor RT1 made of a copper tube.
A magnetic path cylinder MT1 made of a magnetic material is mounted coaxially with the magnetic path cylinder MT1. Three arc-shaped stators LM1 are attached along the vacuum vessel wall outside the vacuum vessel VV in a state facing the rotor RT1. The above rotor RT
Numeral 1 is disposed so as to be sandwiched between the magnetic path cylinder MT1 and the stator LM1. The rotor RT1 is the stator LM1
, A rotational torque is given through electromagnetic induction through a wall made of a non-magnetic material of the vacuum vessel VV, so that the anode-side rotating body assembly AR connected thereto rotates. The center axis of rotation of the X-ray target TG coincides with the center axis CC 'of rotation of the cathode 1 included in the electron gun assembly EG, and the cathode 1 is always opposed to the surface of the X-ray target TG. Rotate in opposite directions.

Referring to FIG. 3 or FIG. 4, cathode power supply mechanism SL
1 will be described. In this embodiment, three cathode power supply mechanisms SL1 are coaxially mounted to form three independent current paths. Electron gun assembly EG cathode 1
Is the orbital center axis C of the electron gun assembly EG in the vacuum vessel VV.
It is electrically connected to the high voltage terminal HT through an annular cathode power feeding mechanism SL1 having the same central axis as C ′. To the high voltage terminal HT, a negative high voltage of about -150 KV and power for heating the cathode 1 of the electron gun assembly EG are supplied from a high voltage power supply (not shown) provided outside the vacuum vessel VV. Each cathode power supply mechanism SL1 has a fixed part and a rotating part, and the fixed part is a vacuum vessel V while maintaining electrical insulation via an insulator 220.
It is mechanically fixed to a part of V. Cathode feeding mechanism SL
The rotating unit and the fixed unit 1 constitute a dynamic pressure sliding bearing using a liquid metal as a lubricant, and electricity is supplied between the two via a liquid metal lubricant. The rotating part of the cathode power supply mechanism SL1 is mechanically connected to the electron gun assembly EG by an elastic rotation torque transmission mechanism 217, and the cathode power supply mechanism SL1 allows some eccentricity and axial displacement. It rotates with the electron gun assembly.

The X-ray target TG is an anode side rotating body assembly A
It is electrically and thermally coupled to the vacuum vessel VV via a liquid metal lubricant present in a bearing mechanism ABG comprising an R dynamic pressure sliding bearing. The vacuum vessel VV is at the ground potential and is forcibly cooled with cooling water or the like. Therefore, the X-ray target TG is connected to the ground potential, and a large amount of heat generated from the X-ray target TG is efficiently removed by the cooling water flowing through the wall of the vacuum vessel VV via the liquid metal lubricant. Since the thermal resistance between the X-ray target TG and the cooling water is sufficiently small, the temperature of the X-ray target TG is kept low, so that a large input is allowed and an extremely large amount of X-rays can be generated in a short time. it can.

The electron gun assembling EG is shown by F in FIG.
As shown at 1, F2, and F3, three are mounted at equal intervals around the cathode side rotating body assembly CR. Here, F1, F2,
F3 indicates three focal points of X-rays generated when the electrons 2 are accelerated and collide with the X-ray target TG. The X-ray focal points F1, F2, and F3 simultaneously generate X-rays while
As shown in (B), they go around in the same direction at the same time. The current positions of these X-ray focal points are detected by an angle detection mechanism (not shown) attached to the cathode side rotating body assembly CR. X-rays emitted from the X-ray focal points F1, F2, F3 are:
As shown in FIG. 2 (A) or FIG. 3 or FIG. 4, the fan-shaped distribution shaper is shaped like a fan by the X-ray distribution limiting mechanism inside the X-ray target TG and attached to the cathode side rotating body assembly CR. After passing through the WF (see FIG. 4) to optimize the X-ray intensity distribution in the fan direction, it passed through the X-ray emission window XW (see FIG. 4) of the vacuum vessel VV and passed through the external annular slit SLT. Later, the light passes through the subject M and reaches the respective opposing surfaces of the two annular X-ray detectors DF and DB mounted coaxially with the X-ray target TG.

As shown in FIG. 2B, the X-ray focal points F1,
The X-rays emitted from F2 and F3 are received by the subdivided detection elements, respectively, in the opposite parts D1, D2 and D3 of the detector. The irradiation field range and the like are determined so that the detector portions D1, D2, and D3 do not overlap each other. Since the sum of the detector portions D1, D2, and D3 occupies almost all of the annular detector, all the detecting elements in the X-ray detectors DF and DB are effectively used, and the cost / performance ratio is improved. Each of the annular detectors DF and DB has a central axis CC '.
Is also divided into a large number of detection element rows, the signals detected by each detection element are converted into digital signals by an electronic circuit (not shown), reconstructed into a tomographic image by a computer (not shown), and an image (not shown) A multi-slice CT image can be displayed on a display device.

FIG. 4 is an enlarged view of a part of the section including the cathode power supply mechanism SL1 which is located vertically above at a certain moment.
And the same parts are denoted by the same symbols. The cathode-side rotating body assembly CR has a generally rotationally symmetrical structure as a whole, and the components such as the electron gun assembly EG attached thereto are small and lightweight, so that they can sufficiently withstand high-speed rotation of about 10 rps. In this case, since there are three X-ray focal points, the scan time can be reduced to 0.03 seconds. The X-ray target TG has a large diameter of 120 cm, rotates in the direction opposite to the X-ray focal points F1, F2, and F3, and is forcibly cooled as described above, so that the surface temperature of the X-ray target TG increases. Since it is difficult to input a large amount of power, a sufficient amount of X-rays can be generated in a short time, and a high-quality CT image with little photon noise can be obtained despite ultra-high-speed scanning. For example, a tube current of 2400 mA can be obtained. In addition, since multi-slices are realized, X-rays can be used effectively,
Not only can the resolution in the direction parallel to the central axis CC 'be increased, but also a wide range of imaging can be completed in a short time to obtain a three-dimensional real-time CT image.

What is unavoidable in order to realize the X-ray CT scanner having the above configuration is to realize a cathode power supply mechanism SL1 which can be practically used in the above-described device configuration. Conventionally, an inexpensive power supply mechanism with a large turning radius that can be used in a vacuum has not been realized. There are some proposals to supply power to a rotating body in a non-contact manner by using an electromagnetic induction action, but none of them has been put to practical use due to its complicated structure. In the present invention, as will be described later with reference to FIG. 5, a bearing rotating body and a bearing fixing body are provided, a bearing gap is provided on the opposing surfaces thereof, and a liquid metal lubricant is filled therein to provide a small dynamic pressure. A sliding bearing is formed, and while the bearing rotating body floats on the liquid metal lubricant, the bearing rotating body and the bearing fixed body are electrically short-circuited through the liquid metal lubricant to stably supply power to the bearing rotating body. . This can be considered as a slip ring in a broad sense.

As shown in FIGS. 3 and 4, a plurality of the cathode power supply mechanisms SL1 are arranged and used coaxially to constitute a forward path and a return path in a vacuum. Further, in order to configure many circuits, as many cathode power supply mechanisms SL1 are used.
The rotating portions of the plurality of cathode power supply mechanisms SL1 need to rotate simultaneously, and it is extremely difficult to match the centers of rotation with high accuracy. In addition, these rotating parts need to rotate in synchronization with a component to be fed, for example, the electron gun assembly EG.
It is also very difficult to accurately match C ′ with the rotation center axis of the cathode power supply mechanism SL1. In order to solve this problem, the electron gun assembly EG and the rotating part of the cathode power supply mechanism SL1 are connected by using a rotation torque transmission mechanism 217 made of a thin leaf spring. The leaf spring is wide in the circumferential direction of the rotating portion and does not deform in the circumferential direction, but easily deforms in the radial direction or the rotation axis direction. For this reason, a strong rotational force can be applied to the rotating part of the cathode power supply mechanism SL1, but the deviation of the rotation center is allowed, and this problem has been solved.

Another problem to be solved is that it is necessary to provide insulation to keep the rotating portion of the cathode feeding mechanism SL1 at a high voltage. The diameter of the cathode power supply mechanism SL1 is about 120 cm, and it is almost impossible to produce an insulator of the same size. Therefore, a large number of columnar ceramics 220 to which the electric field relaxation mechanisms 222 and 223 are attached are arranged in the circumferential direction of the cathode power supply mechanism SL1, and the cathode power supply mechanism SL1 is attached thereto. In order to reduce deformation due to heat generation in the dynamic pressure sliding bearing constituting the cathode power supply mechanism SL1, ceramic having a large thermal conductivity such as aluminum nitride is employed.

However, since the ceramic is not continuous in the circumferential direction of the cathode power feeding mechanism SL1, temperature unevenness occurs in the circumferential direction, and due to the influence, abnormal deformation occurs in the bearing fixed body constituting the cathode power feeding mechanism SL1, and the normal state occurs. Operation may be hindered. In order to solve this, the following ideas were adopted. As shown in FIG. 4, a temperature equalizing ring 22 made of a metal having a large thermal conductivity, for example, copper and having substantially the same diameter as the cathode power supply mechanism.
A plurality of the above-mentioned ceramics 220 were arranged at intervals in the circumferential direction. As shown in FIGS. 4 and 5, another temperature equalizing ring 216 having substantially the same diameter as the cathode power supply mechanism SL1 and having a large thermal conductivity is attached to the other end of these ceramics concentrically with the cathode power supply mechanism SL1. The temperature equalizing ring 216 is connected via a stress absorbing mechanism 215 to a fixed part mounting ring 214 for supporting the cathode power supply mechanism SL1. The stress absorbing mechanism 215 is provided with a portion having a different radius, that is, a convex portion or a concave portion, so that a thin metal plate can be bent in a radial direction to absorb deformation. The rigidity of the stress absorbing mechanism 215 is
6 and the fixed portion mounting ring 214, the thermal deformation of the temperature equalizing ring 216 is not transmitted to the fixed portion mounting ring 214, and the deformation of the cathode power supply mechanism SL1 can be prevented. In this way, this problem has been solved.

In order to operate the cathode power supply mechanism SL1 stably for a long period of time, it is important to provide a structure in which the liquid metal lubricant does not leak from the dynamic pressure sliding bearing constituting the cathode power supply mechanism SL1. Generally, in order to obtain a sufficient dynamic pressure of a dynamic pressure sliding bearing, the size of a bearing gap formed between the bearing rotating body and the bearing fixed body constituting the sliding pressure bearing is limited to several tens of μm. For example, when the size of the bearing gap is 50 μm, the size of the gap at the opening of the bearing is almost the same. When the height drop of the liquid metal lubricant exceeds about 18 cm, the static pressure of the liquid metal lubricant due to gravitational acceleration causes the static pressure of the bearing to increase. The liquid metal lubricant leaks out of the bearing overcoming the pressure effect of surface tension at the opening. This becomes a serious problem when the rotating part of the bearing stops rotating. In particular, as in the case of the present invention, the height drop of the opening of the bearing is 1
With a hydrodynamic sliding bearing of about 20 cm, it was impossible to realize the conventional technology.

Referring to FIG. 5, an embodiment of the dynamic pressure sliding bearing of the cathode power supply mechanism SL1 will be described. FIG. 5 is an enlarged view of a part of the cross section of the cathode power supply mechanism SL1. The upper part of FIG. 5 shows a part located vertically above at a certain moment in actual use, and the lower part shows a part located vertically below at the same moment. In FIG. 5, the central part is omitted and is shortened and displayed. The cathode power supply mechanism SL1 includes a fixed part mounting ring 214, a bearing fixed body 202 connected thereto,
A bearing rotating body 201 is fitted to the inner surface so that the outer surface is opposed to the outer surface with a gap, and a rotating part mounting ring 213 connected thereto. The dynamic pressure sliding bearing is composed of a bearing fixed body 202, a bearing rotating body 201, a bearing gap formed between the bearing fixed body 202 and the bearing rotating body 201, and a liquid lubricant at room temperature filled therein.

The cathode power supply mechanism SL1 is mounted with a rotation center substantially the same as the rotation center CC 'of the electron gun assembly EG, and the rotation part mounting ring 213 is a rotation torque transmission mechanism composed of the thin leaf spring. It is rotated simultaneously with the electron gun assembly EG via 217. The bearing fixing body 202 and the bearing rotating body 201 have surfaces facing each other, and the facing surfaces correspond to the first bearing gaps 203 and 208, the second bearing gaps 204 and 209, and the third bearing gap 20.
6, 211. At least one of the opposing surfaces forming the bearing gap has a herringbone-shaped bearing groove. The first, second and third bearing gaps are filled with a liquid metal which is liquid at room temperature, preferably a lubricant made of an alloy of gallium, indium and tin, and these bearing gaps are radially The bearing gaps correspond to the respective bearing gaps of the first thrust bearing and the second thrust bearing which are mounted to face each other with the bearing interposed therebetween.

When a rotational torque is applied to the bearing rotating body 201, a dynamic pressure is generated in the liquid metal lubricant, so that the bearing rotating body 201 can be floated and rotatably supported. When the bearing rotator 201 is rotating, the action of confining the liquid metal lubricant in each bearing gap inside the bearing occurs, so that the liquid metal lubricant leaks from the bearing gap into the vacuum space outside the bearing. do not do.

As shown in FIG. 5 or FIG. 6, the opposing surfaces formed by the bearing fixing body 202 and the bearing rotating body 201 have first end gaps 205 and 210 and a second end gap 2.
07, 212 and the bearing gap 20 of the radial bearing.
3, 208; first end gaps 205, 210;
The central axes of the opposing surfaces constituting the second end gaps 207 and 212 coincide with CC ′ in a state where they are substantially horizontal. Bearing gap 204,2 of first thrust bearing
09, and the bearing gap 206 of the second thrust bearing,
The respective opposing surfaces constituting the 211 are flat, and the bearing gaps 204 and 209 of the first thrust bearing are formed.
Are the radial bearing gaps 203, 208 and the first end gaps 205, 210, the second thrust bearing gaps 206, 211 are the radial bearing gaps 203, 208 and the second end gap 207. , 2
And 12. First end gap 205, 2
10 and the diameters of the opposing surfaces forming the second end gaps 207, 212 are the same as the radial bearing gaps 203, 20.
8 is smaller than the diameter of the facing surface. The size of the first end gaps 205, 210 and the size of the second end gaps 207, 212 are larger than the size of the radial bearing gaps 203, 208 and the first end gaps 205, 210 And the second end gaps 207, 212 are both in communication with the vacuum space, and have opposing surfaces which are not wetted by the liquid metal lubricant (not shown). An annular bearing opening 32 is provided between the bearing gaps 204, 209 of the first thrust bearing and the first end gaps 205, 210.
1, 321 ', bearing gaps 206, 211 of the second thrust bearing and second end gaps 207, 212.
Between them are annular bearing openings 320, 320 '. These bearing openings have opposing surfaces that are not wetted by the liquid metal lubricant and a gap sandwiched therebetween. Bearing gaps 203 and 208, bearing gap 204
And 209, the bearing gaps 206 and 211, the end gaps 205 and 210, the end gaps 207 and 212, the bearing openings 320 and 320 ', and the bearing openings 321 and 321' are the same respectively, and different numbers indicate the positions indicated. Represents the difference. Here, the bearing gap indicates that the bearing groove is provided on at least one of the opposing surfaces, and the end gap has the non-wetting surface on at least one of the opposing surfaces. It is shown that.

When the bearing rotator 201 stops rotating, surface tension acts on the liquid metal lubricant in the bearing openings 320 and 320 'and the bearing openings 321 and 321', and the liquid metal lubricant is removed. Leakage to the outside is prevented. The static pressure in the liquid metal lubricant due to gravitational acceleration is proportional to the depth of the liquid metal lubricant from the waterline. In other words, the higher the static pressure in the liquid metal lubricant vertically below, the greater the pressure. On the other hand, the pressure effect of the surface tension is inversely proportional to the size of the gap in the bearing opening. Therefore, if the size of the gap of the bearing opening is made smaller toward the lower part in the vertical direction, it is possible to prevent the liquid metal lubricant from leaking from the inside of the dynamic pressure sliding bearing having a large diameter. As schematically shown in FIG. 6, the size of the gap in each bearing opening is the first end gap 205, 210.
And the size of the second end gaps 207, 212. Here, the size of the first and second end gaps is the bearing gap 2 of the radial bearing.
Since it is only slightly larger than the size of 03,208, the size of the gap in the bearing opening is approximately equal to the size of the bearing gap 203,208 in the radial bearing.

One of the means for easily realizing the above is shown in FIG.
As shown in FIG. 6, the bearing rotating body 201 is mounted inside the bearing fixing body 202 constituting the cathode power feeding mechanism SL1. In this way, when the bearing rotating body 201 stops rotating, the bearing rotating body 2 is affected by the gravitational acceleration.
01 is lower by a distance d vertically below the center axis of the bearing fixed body, and comes into contact with the bearing fixed body 202 at the vertically lowermost end portion 208 of the first bearing gap, thereby substantially reducing the bearing gap 208. The size becomes zero. Due to this effect, the portion 21 located at the vertical lowermost end of the first end gap 21
0, the size of the gap is also minimized in the portion 212 located at the vertical lowermost end of the second end gap, and the portions 320 and 32 located at the vertical lowermost end of the bearing opening are formed.
1, a sufficiently large pressure effect of the surface tension can be obtained, and the leakage of the liquid metal lubricant into the vacuum space can be prevented. The size of the gap of the bearing opening increases as the position becomes vertically higher, and the pressure effect of the surface tension here decreases, but the static pressure of the liquid metal lubricant also decreases. Vertical top 320 ', 32 of the bearing opening
The size of the gap at 1 'is approximately 2d, which is the maximum value, so that the pressure effect of the surface tension of the liquid metal lubricant here is minimized, but the height drop here is the difference between the height of the second and third bearings. Approximately equal to the width (eg, 1 cm or less), the static pressure generated here is a small value, and the pressure effect of surface tension is greater. However, since the rate of change of the size of the gap of the bearing opening with respect to the vertical height is small in a portion located in the middle of the bearing opening in the vertical direction, the effect of the surface tension is smaller than the static pressure at the same point in this portion. Also occurs. The means for eliminating this inconvenience will be described below.

When the bearing rotor 201 stops rotating, the liquid level height of the liquid metal lubricant from the vertical lowermost portions 320 and 321 of the bearing opening is H, and the bearing rotor at the position of the bearing opening is H. Is the radius of the surface of the liquid metal lubricant, ρ is the density of the liquid metal lubricant, g is the gravitational acceleration, γ is the surface tension coefficient of the liquid metal lubricant at the vertically lower ends 320 and 321 of the bearing openings, and γ is the bearing rotor 201. Assuming that the distance between the central axis of the bearing fixed body 202 and the central axis of the bearing fixing body 202 is d, if the value of d is equal to or less than the value calculated by 8γR / (ρgH ² ), the bearing openings 320 and 320 ′ and the bearing Openings 321, 32
From the result of the numerical calculation, it was found that the pressure effect of the surface tension of the liquid metal lubricant at an arbitrary point P of 1 ′ becomes larger than the static pressure at the same point. For example, γ = 500 dy
n / cm, ρ = 5.6 g / cm ³ , R = 60 cm, g =
Considering the case of 980 cm / sec ² , if H = 12
In the case of 2 cm, if d is set to 29 μm or less, the pressure effect of the surface tension over the entire periphery of the bearing openings 320 and 320 ′ and the bearing openings 321 and 321 ′ exceeds the static pressure at the same point. No liquid metal lubricant leaks out in position. When H = 50 cm, the same effect can be obtained by setting d to 174 μm or less. Furthermore,
If H = 20 cm, the same effect can be obtained if d is 1093 μm or less. The value of d above is approximately equal to the average value of the size of the gap of the bearing opening over the entire circumference. Means for setting the value of H when the bearing rotor 201 stops rotating to a value smaller than the diameter 2R 'of the surface of the bearing fixed body at the position of the bearing opening will be described below.

When the distance d between the center axis of the bearing rotator 201 and the center axis of the bearing fixing body 202 is larger than 29 μm, the liquid metal will be removed when the bearing rotator 201 stops rotating. The liquid metal lubricant so that the waterline of the lubricant is lower than the height of a point 205 located vertically on the first end gap or the height of a point 207 located vertically on the second end gap. It is good to set the amount of. In order to realize this, the bearing rotating body 201, the bearing fixed body 202, the bearing openings 320 and 320 ', and the bearing opening 3
It is preferable that the volume of the liquid metal lubricant filled in the lubricant existing region be smaller than the volume of the lubricant existing region surrounded by 21, 321 '. Furthermore, a space in which the liquid metal lubricant can wait vertically below when the bearing rotor 201 stops rotating is included in the lubricant existing area, and when the bearing rotor 201 is rotating, all of the above-mentioned conditions are included. It is preferable that the bearing gap is filled with the liquid metal lubricant. Another means will be described. A tube opening at the vertical lowermost end of the lubricant existing region is attached to the bearing fixing body 202, and this tube is connected to the vacuum vessel V
V and the tube is connected to a lubricant container provided outside the vacuum container VV. The liquid metal lubricant is allowed to move into the lubricant container, and the height of the lubricant container in the vertical direction can be changed so that the inside of the vacuum container VV is maintained in a high vacuum state. The liquid surface height H of the liquid metal lubricant in the lubricant existing region is controlled from outside the vacuum vessel VV according to the principle of the communication pipe. For example, when the bearing rotator 201 stops rotating, the lubricant container is moved vertically downward to lower the liquid level H in the lubricant existing area, and conversely, the bearing When the rotating body 201 is rotating, the lubricant container is moved vertically upward to increase the liquid level H in the lubricant existing area. In this way, even when the diameter of the bearing opening exceeds 120 cm, the pressure effect of the surface tension can be made larger than the static pressure of the liquid metal lubricant at any position in the circumferential direction of the bearing opening. It is possible to provide the cathode power supply mechanism SL1 including a dynamic pressure sliding bearing in which the liquid metal lubricant does not leak even at the position. In addition, since the amount of the liquid metal lubricant in the vacuum vessel can be controlled from outside the vacuum vessel, not only the best lubrication state can be always maintained, but also the maintenance of the bearing becomes easy.

When the bearing rotating body 201 constituting the dynamic pressure sliding bearing of the cathode power feeding mechanism SL1 is rotating at a sufficiently high speed, a relatively large bearing loss occurs in each bearing gap. The fixed body 202 is kept at a low temperature because it is thermally connected to the vacuum vessel VV, which is forcibly cooled from the outside, via an insulator 220 having a large thermal conductivity. However, since the temperature of the bearing rotating body 201 is relatively higher than the temperature of the bearing fixed body 202, it is necessary to prevent the size of the bearing gap from decreasing during operation. To achieve this, the bearing rotor 201
Is made smaller than that of the material forming the bearing fixed body 202. In particular, when the rotation speed of the bearing rotating body 201 increases, expansion due to centrifugal force occurs, and if the bearing gap is to be narrowed, bearing loss increases and heat generation in this part increases, and the bearing fixing The expansion of the body 202 is prevented from being larger than that of the bearing rotor 201, and the size of the bearing gap is prevented from being reduced. The cathode power supply mechanism SL1 of the present invention is characterized in that the rotating part itself has a bearing structure, the load on the bearing is small, and the energizing action is performed through its own lubricant. You can continue for a long time.

Although the present invention has been described with reference to illustrative embodiments, the present invention is not intended to be limited to the structure and form of the embodiments illustrated herein, but to be departed from the spirit and scope of the invention. It is to be understood that various embodiments are possible and that various changes and modifications can be made. For example, in the present invention, three electron gun assemblies are attached, but one or three or more electron gun assemblies may be used. Further, in the present invention, the structure in which both the cathode side rotating body assembly CR and the X-ray target TG are rotated is shown. However, the cathode scan type X-ray having a structure in which the X-ray target TG and a portion connected thereto are fixed. It includes a generator and an X-ray CT scanner using the same. Of course, a large number of cathode power supply mechanisms SL1 can be attached to supply power to many electron gun assemblies at the same time. Further, in the above embodiment, an example is shown in which a metal that is liquid at normal temperature is used as a lubricant.However, even if it has a rather high melting point and is solid at normal temperature, it is heated and liquefied before operation. Of course, the same effect can be obtained by operating. Further, the X-ray emission window for taking out the X-rays generated from the X-ray target outside the vacuum vessel may be integrated with the vacuum vessel or may be configured as a part of the vacuum vessel. If the X-ray attenuation rate at the part is small, X
Of course, it can be regarded as a line emission window. Needless to say, the vacuum vessel VV does not have to have a rotationally symmetric shape. It goes without saying that the center axis of the vacuum vessel and the center axis of the cathode side rotating body assembly or the anode side rotating body assembly may be deviated to some extent. It is needless to say that the X-ray target is divided and each divided part may have a gap. In the present invention, the size of the gap means the shortest distance from any point on one of the opposing surfaces forming the gap to the other of the opposing surfaces forming the gap. .

The present invention realizes an X-ray CT scanner capable of performing ultra-high-speed scanning as described above. The present invention can be applied to an electron beam irradiation device for irradiating an electron beam from a device. That is, the X-ray target and the parts related thereto, the X-ray X-ray distribution limiting mechanism, the fan direction distribution shaper WF, and other X-ray related parts are omitted from the device configuration described in the above embodiment, and the X-ray The emission window XW is changed to an electron beam emission window made of a thin titanium plate, and the direction of emitting electrons from the electron gun assembly EG is changed to the direction of the electron beam emission window. When this is used, it is possible to provide an electron beam irradiation apparatus which can be used for plastics, glass, and other modification treatments and has a large industrial effect.

[0035]

As described above, when the cathode scan type X-ray generator of the present invention is employed, the rotating part can be formed into a structure in which light parts are attached to a substantially rotationally symmetric structure inside the vacuum vessel, so that centrifugation is performed. Ultra-high-speed scan type X-ray C with less influence of force, for example, a scan time of 0.03 seconds
The T scanner can be realized at a low cost with a simple structure. In particular, a large amount of X
Lines can be generated, and a sufficiently high-quality image with little photon noise can be obtained. The generated X-rays are effectively received by the annular surface detector, and a large number of cross-sections in a wide area can be instantaneously photographed. Using this data, the three-dimensional internal structure of the subject can be instantaneously obtained. Be able to inspect. For this reason, it is possible to provide an X-ray CT scanner capable of faithfully and immediately imaging even a portion that moves quickly, such as a human heart, inside the subject. The cathode power supply mechanism uses a hydrodynamic sliding bearing that uses liquid metal as a lubricant, so that it can supply power to the cathode stably for a long time in a vacuum and also keeps the resistance of the rotating part at a small and constant value. Therefore, stable X-rays can be generated. Further, the heat generated in the dynamic pressure sliding bearing can be effectively guided to the outside of the vacuum vessel and cooled. Since there is no external mechanical rotation mechanism and the related power supply and electronic circuit can be used in a stationary state, the overall reliability is high, and the compact cathode scan type X-ray generator and the X-ray CT using the same are available. A scanner can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic cross section of a conventional X-ray CT scanner.

FIGS. 2A and 2B are a schematic cross-sectional view and a front view showing a main part of an entire structure of a cathode scan type X-ray generator and an X-ray CT scanner according to the present invention.

FIG. 3 is a schematic sectional view showing the entire structure of a cathode scan type X-ray generator and an X-ray CT scanner according to the present invention, and is an enlarged view of FIG. 2 (A).

FIG. 4 is an enlarged schematic cross-sectional view of a portion of the cathode scan type X-ray generator according to the present invention, which is located vertically above at a certain moment.

FIG. 5 is an enlarged cross-sectional view of a part of a cathode power supply mechanism which is a main part of the cathode scan X-ray generator according to the present invention.

FIG. 6 is an enlarged cross-sectional view schematically showing a part of a main part of a cathode power supply mechanism included in the cathode scan type X-ray generator according to the present invention.

[Explanation of symbols]

ABG Anode-side bearing mechanism AR Anode-side rotating body assembly B Bed CBG Cathode-side bearing mechanism CR Cathode-side rotating body assembly DB Rear detector assembly DF Front detector assembly D1 Part of detector DF, DB D2 Detector DF, Part of DB D3 Detector DF, Part of DB EG Electron gun assembly F1 X-ray focal point F2 X-ray focal point F3 X-ray focal point HT High voltage terminal LM1 Arc-shaped stator LM2 Arc-shaped stator M Subject MT1 Magnetic path cylinder MT2 Magnetic path cylinder RT1 Rotor RT2 Rotor SL1 Cathode feeding mechanism SLT Slit TG X-ray target VC Exhaust port VV Vacuum container WF Fan direction distribution shaper XW X-ray emission window 1 Cathode 2 Electron beam 201 Bearing rotating body 202 Bearing fixed body 203 Radial Vertical upper part of bearing gap 204 Vertical upper part of bearing gap of first thrust bearing 205 Vertical upper part of end gap 206 Vertical upper part of bearing gap of second thrust bearing 207 Vertical upper part of end gap 208 Vertical lower part of radial bearing gap 209 Vertical lower part of bearing gap of first thrust bearing 210 End Vertical lower part of the unit gap 211 Vertical lower part of the bearing gap of the second thrust bearing 212 Vertical lower part of the end gap 213 Rotating part mounting ring 214 Fixed part mounting ring 215 Stress absorbing mechanism 216 Temperature uniforming ring 217 Rotary torque transmitting mechanism 220 Insulator 221 Temperature uniforming ring 222 Electric field relaxation mechanism 223 Electric field relaxation mechanism 320 Vertical lower part of bearing opening 320 'Vertical upper part of bearing opening 321 Vertical lower part of bearing opening 321' Vertical upper part of bearing opening 1001 Fixed gantry of conventional X-ray CT scanner 1002 Conventional X-ray C Rotary mount of scanner 1003 Bearing of conventional X-ray CT scanner 1004 X-ray tube of conventional X-ray CT scanner 1005 X-ray of conventional X-ray CT scanner 1006 Detector of conventional X-ray CT scanner 1007 Conventional X-ray CT Electronic circuit of scanner 1008 Controller of conventional X-ray CT scanner 1009 Rotation drive mechanism of conventional X-ray CT scanner

Claims (13)

[Claims] 1. A donut-shaped vacuum container for forming a vacuum space by maintaining a vacuum state inside the vacuum container, and supported in the vacuum space inside the vacuum container so as to be rotatable coaxially with a center axis of the vacuum container. A cathode side rotating body assembly, an electron gun assembly attached to a part of the cathode side rotating body assembly, a cathode attached to the electron gun assembly and emitting electrons, and A cathode power supply mechanism for supplying power from the outside, an annular X-ray target attached to face the orbit of the cathode, and X-rays generated on the surface of the X-ray target being outside the vacuum vessel. An X-ray emission window for taking out the light, a rotary drive mechanism for applying a rotational force to the cathode-side rotating body assembly, and a bearing mechanism for rotatably supporting the cathode-side rotating body assembly in a vacuum vessel. Is composed of the above The cathode power supply mechanism includes a bearing mechanism. The bearing mechanism includes an annular bearing fixed body that is a part for fixing the bearing mechanism, and an annular bearing rotating body that is a rotating part. The fixed body and the bearing rotating body have bearing surfaces facing each other with a gap,
At least one of these bearing surfaces is provided with a herringbone-shaped bearing groove, and a bearing gap formed between the bearing surfaces is filled with a liquid metal lubricant that is liquid during operation. A cathode scan type X-ray generator, wherein a metal lubricant, the bearing rotating body, and the bearing fixed body can supply power to the cathode from outside the vacuum vessel, And an X-ray CT scanner using the same. 2. The bearing rotating body is configured to float by a dynamic pressure generated in the liquid metal lubricant during rotation, and the bearing fixed body and the bearing rotating body are formed of the liquid metal lubricant. Two annular bearing openings, which are substantially boundaries of the presence of the lubricant, and an end gap having a surface that is not wetted by the liquid metal lubricant, are formed at each of the end openings. 2. The cathode scan type X-ray generator according to claim 1, wherein the X-ray generator communicates with the vacuum space through a gap, and an X-ray CT scanner using the same. 3. The cathode scan type X-ray generator according to claim 2, wherein the size of the gap between the opposing surfaces forming the bearing opening is smaller in a portion located vertically downward. Device and X-ray CT using it
Scanner. 4. A bearing according to claim 3, wherein a surface of the bearing rotating body among the facing surfaces constituting the bearing opening has a smaller diameter than a surface of the bearing fixed body. An X-ray CT scanner using the cathode scan type X-ray generator described above. 5. The volume of a lubricant existing area formed by the bearing rotating body, the bearing fixed body, and the two bearing openings is a liquid filled in the lubricant existing area. The cathode scan type X-ray generator according to any one of claims 2 to 4, wherein the volume is larger than the volume of the metal lubricant, and an X-ray CT scanner using the same. 6. A passage communicating with the outside of the vacuum vessel is provided in a lubricant existing region formed by the bearing fixing body, the bearing rotating body, and the two annular bearing openings. Through the passage, the amount of the liquid metal lubricant present in the lubricant existing region can be changed from outside the vacuum vessel while keeping the inside of the vacuum vessel at a high vacuum state. The cathode scan type X-ray generator according to any one of claims 2 to 5, and an X-ray CT scanner using the same. 7. The bearing rotating body and the bearing fixed body are thermally coupled via the liquid metal lubricant, and the bearing fixed body is connected to the vacuum via an electrical insulator. The cathode scan type X-ray generator according to any one of claims 1 to 6, wherein the X-ray CT scanner is cooled by cooling from the outside of the container. 8. A bearing according to claim 3, wherein a coefficient of thermal expansion of a material forming said bearing fixed body is larger than a coefficient of thermal expansion of a material forming said bearing rotating body. And a X-ray CT scanner using the same. 9. The bearing mechanism according to claim 1, wherein said bearing mechanism is supported by a plurality of insulator blocks via a stress relaxation mechanism having a function of reducing non-rotationally symmetric deformation. A cathode scan type X-ray generator according to one or more aspects and an X-ray CT scanner using the same. 10. The stress relaxation mechanism includes a first ring connected to the bearing fixing body, and a second ring provided at a distance from the first ring and facing the first ring. 10. The cathode scan type X-ray generator according to claim 9, wherein the first ring and the second ring are connected to each other by an annular structure having a lower rigidity than the second ring. Device and X-ray CT scanner using the same. 11. The device according to claim 9, wherein the plurality of insulator blocks are commonly sandwiched and mounted by a temperature equalizing ring made of a material having a higher thermal conductivity. A cathode scan type X-ray generator and an X-ray CT scanner using the same. 12. The bearing rotating body is provided with a rotating torque via a rotating torque transmitting mechanism connected to the cathode side rotating body assembly or a component attached to the cathode rotating body assembly. 2. The cathode scan type X-ray generator according to claim 1, wherein the rigidity of the bearing rotating body in a direction allowing at least one of eccentricity and axial displacement is reduced. X-ray C
T scanner. 13. A donut-shaped vacuum vessel which forms a vacuum space by holding the inside of the vacuum state, and is supported so as to be coaxially rotatable in the vacuum space inside the vacuum vessel with the center axis of the vacuum vessel. A cathode-side rotating body assembly, and an electron gun assembly attached to a part of the cathode-side rotating body assembly,
A cathode attached to the electron gun assembly for emitting electrons; a cathode power supply mechanism for supplying power to the cathode from outside the vacuum vessel; and a cathode power supply mechanism for extracting accelerated electrons emitted from the cathode. An electron beam emission window, a rotation drive mechanism for applying a rotational force to the cathode-side rotating body assembly, and a bearing mechanism for rotatably supporting the cathode-side rotating body assembly in a vacuum vessel. The cathode power supply mechanism has a bearing mechanism, and the bearing mechanism includes an annular bearing fixed body that is a part for fixing the bearing mechanism, and an annular bearing rotating body that is a rotating part. The bearing fixed body and the bearing rotating body have bearing surfaces facing each other with a gap, and at least one of these bearing surfaces is provided with a herringbone-shaped bearing groove. Between the bearing surfaces The bearing gap is filled with a liquid metal lubricant which is liquid during operation, and the cathode can be supplied with power through the liquid metal lubricant, the bearing rotating body, and the bearing fixed body. An electron beam irradiation apparatus, characterized in that: