JP2017054591A - X-ray generation tube and x-ray generation device using the same, x-ray imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the performance maintenance life by moving the focal point of an electron beam on a target by a simple configuration, in a transmission type X-ray generation tube.SOLUTION: An X-ray generation tube includes an insulation tube 3, a positive electrode 7, and a negative electrode 19. The negative electrode 19 has an electron gun 18 including an electron source 12 on the positive electrode 7 side of a neck 14, and the neck 14 has columns 15a, 15b and heating elements 23a, 23b in contact with the columns 15a, 15b. The column 15a or 15b is expanded in the tube axis direction of the insulation tube 3, by electrifying the heating element 23a or 23b, and causing the electron source 12 to tilt relative to a target 4. Emission direction of an electron beam 1 from the electron source 12 is tilted from the tube axis direction of the insulation tube 3, and the position of the focus 8 of an electron beam 1 formed on the target 4 is moved from the center of the target 4 to the radial direction of the insulation tube 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an X-ray generation tube applied to diagnostic applications in medical equipment and non-destructive X-ray imaging in the field of industrial equipment, and an X-ray generation apparatus and X-ray imaging system including the X-ray generation tube.

  In recent years, high-density mounting of electronic component mounting boards has progressed, and inspection objects have become finer. In an X-ray imaging system for detecting a defective portion of these fine parts, an X-ray generator capable of realizing a resolution of about 1 μm to several μm is used.

  In general, a transmission X-ray generator tube can bring an observation object closer to the vicinity of the target as compared with a reflection X-ray generator tube, and is advantageous for high-magnification observation. In the transmission type X-ray generator tube, since X-rays generated at the focal position need to pass through the target material itself and be taken out to the outside, it is necessary to use a heavy metal as a target as a thin film of about several microns. In order to achieve high resolution, it is necessary to reduce the focal size of the electron beam incident on the target that generates X-rays to the same size as the resolution, so the energy of the electron beam is several microns thick. It is necessary to concentrate on a region of 10 μm or less in the thin film material.

  As described above, in a transmission X-ray generator tube, when a fixed position on a target, which is a thin film material, is continuously irradiated with an electron beam for a long time, the material is worn out by evaporation, migration, etc. of the target material at the focus of the electron beam. As a result, the performance maintenance life may be shortened. In order to extend the performance maintenance life, it is effective to appropriately move a minute focus on the target in accordance with the amount of electron beam irradiation. For example, Patent Document 1 includes a configuration in which a vacuum bellows is provided in a part of a vacuum vessel of an X-ray generator tube, a cathode side is a movable flange, and an axial direction of an electron gun fixed to the flange can be deflected minutely. Is disclosed.

No. 4-3384

  However, the X-ray generating tube disclosed in Patent Document 1 must use an expensive vacuum bellows, and there is a concern that a vacuum leak may occur from the bellows when used for a long period of time.

  An object of the present invention is to extend the performance maintenance life of a transmission X-ray generator tube used in a high-resolution X-ray generator by moving the focal point of an electron beam on a target with a simple configuration. It is another object of the present invention to provide an X-ray generation apparatus and an X-ray imaging system using an X-ray generation tube with an extended performance maintenance life.

The first of the present invention is an insulating tube,
An anode comprising: a target that generates X-rays by irradiation of an electron beam; and an anode member that holds the target and is connected to one end of the insulating tube;
A cathode member connected to the other end of the insulating tube; a neck portion having one end connected to the cathode member and an electron source fixed to the other end; and an electron beam emitted from the electron source to the target A cathode having an electron gun for irradiation;
In an X-ray generator tube having
The neck portion has a deformation portion, and the deformation of the deformation portion causes a tilt in the direction of the electron source with respect to the target or moves the position of the electron source in a direction crossing the longitudinal direction of the neck portion. It is characterized by making it.

  A second aspect of the present invention includes the X-ray generation tube of the present invention, a storage container storing the X-ray generation tube, and an insulating fluid filled in an extra space inside the storage container. The X-ray generator characterized by the above.

The third aspect of the present invention is the X-ray generator of the present invention,
An X-ray detector that detects X-rays generated from the X-ray generator and transmitted through the subject;
An X-ray imaging system comprising: a system control device that controls the X-ray generation device and the X-ray detector in a coordinated manner.

  In the present invention, the electron gun on the target is displaced by shifting the direction or position of the electron source by generating an asymmetric deformation around the axial direction of the insulating tube at the neck portion of the electron gun protruding from the cathode member with a simple configuration. The focal point of the line can be shifted in the radial direction of the insulating tube. Therefore, the X-ray generator tube is designed to extend the performance maintenance life of the X-ray generator tube, can be used for a long time, and can be used for a long period of time by using the X-ray generator tube. An x-ray imaging system is provided.

It is a figure which shows typically the structure of one Embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). . FIG. 2 is a diagram showing a state in which the focal point of an electron beam on a target is moved in the X-ray generation tube of FIG. 1, (a) is a plan view showing main members, and (b) is an AA in (a). 'Cross section. It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. FIG. 6 is a diagram showing a state in which the focal point of an electron beam on a target is moved in the X-ray generator tube of FIG. 5, (a) is a plan view showing main members, and (b) is an AA in (a). 'Cross section. It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. FIG. 8 is a diagram showing a state in which the focal point of the electron beam on the target is moved in the X-ray generating tube of FIG. 7, (a) is a plan view showing main members, and (b) is an AA in (a). 'Cross section. It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. FIG. 10 is a diagram illustrating a state in which the focal point of the electron beam on the target is moved in the X-ray generator tube of FIG. 9, and (b) is a cross-sectional view taken along line A-A ′ in (a). It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. It is a figure which shows typically the structure of other embodiment of the X-ray generator tube of this invention, (a) is a top view which shows a main member, (b) is AA 'sectional drawing in (a). is there. It is sectional drawing which shows typically the structure of embodiment of the X-ray generator of this invention. It is a block diagram which shows typically the structure of embodiment of the X-ray imaging system of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 to FIG. 13 are diagrams schematically showing a configuration of an embodiment of an X-ray generation tube of the present invention, in which (a) is a plan view and (b) is an AA in (a). 'A cross-sectional view, that is, a cross-sectional view including a tube axis of an insulating tube. In addition, in (a) of each figure, only the main members required for description are shown, and illustration is abbreviate | omitted about another member. The dimensions, materials, shapes, and relative arrangements of the constituent members described in these embodiments do not limit the scope of the present invention. In addition, well-known or publicly known techniques in the technical field are applied to portions that are not particularly illustrated or described in the present specification.

  First, the movement of the focal point of the electron beam on the target in the X-ray generator tube of the present invention will be described with reference to FIGS.

  The X-ray generator tube of the present invention is a transmission type X-ray generator tube, and includes an insulating tube 3, an anode 7, and a cathode 19, as shown in FIG. The anode 7 includes a transmission type target 4 that generates X-rays 2 by irradiation of the electron beam 1 and an anode member 6 that holds the target 4, and the anode member 6 extends in the tube axis direction of the insulating tube 1 at the periphery. Connected to one end.

  The target 4 includes a target layer 4a that generates X-rays 2 when irradiated with an electron beam 1, and a target support substrate 4b made of a material having high X-ray transparency. The target layer 4a is formed in the center of the target support substrate 4b. In the example, they are arranged concentrically. Therefore, in the radial direction of the insulating tube 3, the center of the target 4 is also the center of the target layer 4a.

  The target support substrate 4b has high X-ray permeability, good heat conduction, and must withstand vacuum sealing. For example, diamond, silicon nitride, silicon carbide, aluminum nitride, graphite, beryllium, or the like can be used. More preferably, diamond, aluminum nitride, or silicon nitride, which has a lower X-ray transmittance than aluminum and higher thermal conductivity than tungsten, is desirable. The thickness of the support substrate 4b only needs to satisfy the above functions, and varies depending on the material, but is preferably 0.3 mm or more and 2 mm or less. In particular, diamond is superior in that it has extremely high thermal conductivity compared to other materials, has high radiation transparency, and can easily maintain a vacuum.

  In general, a metal material having an atomic number of 26 or more can be used for the target layer 4a. More preferably, the higher the thermal conductivity, the higher the melting point. Specifically, a metal material such as tungsten, molybdenum, chromium, copper, cobalt, iron, rhodium, rhenium, or an alloy material thereof can be preferably used. The target layer 4a has a thickness of 1 μm to 15 μm, although the optimum value differs because the penetration depth of the electron beam 1 into the target layer 4a, that is, the radiation generation region differs depending on the acceleration voltage. Formation of the target layer 4a on the target support substrate 4b can be performed by means such as sputtering, vapor deposition, and screen printing, and the target 4 can be obtained. As another method, the target layer 4a having a predetermined thickness can be separately produced by rolling or polishing, and the target 4 can be formed by diffusion bonding to the target support substrate 4b under high temperature and high pressure.

As the insulating tube 3, a circular tube is usually used. However, the insulating tube 3 is not limited to this and may be a polygonal tube. When the insulating tube 3 is a polygonal tube, the axis passing through the center of the polygon is the tube axis, and the direction orthogonal to the tube axis is the radial direction. The insulating tube 3 can be made of glass or ceramics, and the inside of the radiation generating tube 1 is a space that is evacuated (depressurized). The inside of the X-ray generation tube has, as an average free path, a degree of vacuum at which the distance between the electron source 12 and the target layer 4a that emits X-rays is realized at least under a pressure at which electrons can fly. Any vacuum pressure of 1 × 10 ⁻⁴ Pa or less is applicable. And the electron source 12 to be used, may be selected as appropriate in consideration of the temperature and the like to operate, for the like cold cathode electron emission source, and more not more than the vacuum pressure 1 × 10 ^-6 Pa preferable. In order to maintain the vacuum pressure in the X-ray generation tube, a getter (not shown) can be arranged inside the insulating tube 3 or installed in an auxiliary space (not shown) communicating with the internal space. .

  For the anode member 6 and the cathode member 11, metal materials such as copper, aluminum, and kovar are preferably used.

  The cathode 19 includes a cathode member 11 connected to the other end of the insulating tube 3 in the tube axis direction, and an electron gun 18 protruding from the cathode member 11 toward the anode 7. The electron gun 18 has a neck portion 14 having one end connected to the cathode member 11, and an electron source 12 is fixed to the other end of the neck portion 14 on the anode 7 side. In this example, the neck portion 14 includes two columns 15 a and 15 b, the electron beam focusing portion 13 is attached to the neck portion 14 on the anode 7 side, and the electron source 12 is not connected to the base of the electron beam focusing portion 13. It is attached via the illustrated insulating member. The electron beam converging unit 13 is regulated to the potential of the cathode member 11 through the columns 15a and 15b, or is independently regulated through a separate potential regulating means. The electron source 12 controls the emission of electrons from the outside of the X-ray generation tube through a wiring 21 drawn to the outside through a current introduction terminal portion 22 made of an insulating material. The electron source 12 may be attached directly to the pillars 15a and 15b via attachment members.

  The electron emission mechanism of the electron source 12 may be any electron source that can control the amount of electron emission from the outside of the vacuum vessel, and a hot cathode electron source, a cold cathode electron source, or the like can be appropriately applied. .

  In the above configuration, electric power is supplied to the electron source 12 through the electric wiring 21 and the electron beam 1 is emitted. The emitted electron beam 1 is focused by the electron beam converging unit 13 and is incident on the target layer 4a to generate X-rays 2. The X-rays 2 pass through the target layer 4a itself and the target support substrate 4b. Radiated to the outside. In FIG. 1, 8 is the focal point of the electron beam 1 on the target layer 4a.

  In this example, the heating elements 23a and 23b are brought into contact with the columns 15a and 15b constituting the neck portion 14, respectively, so that the columns 15a and 15b are deformed portions that can expand and contract in the tube axis direction. The heating elements 23a and 23b are configured so that energization can be individually controlled from the outside by wiring (not shown).

  In the X-ray generating tube of FIG. 1, when the heating elements 23a and 23b are not energized, the lengths of the columns 15a and 15b in the tube axis direction are equal, and the surface of the electron source 12 on the anode 7 side is FIG. At 25 position. Therefore, the electron beam 1 emitted from the electron source 12 advances straight in parallel to the tube axis direction and enters the center of the target 4 to form a focal point 8.

  When the heating element 23a is energized, as shown in FIG. 2B, the column 15a is thermally expanded by heating by the heating element 23a, and the total length in the tube axis direction is longer than the column 15b by t. As a result, at the tip of the neck portion 14, the column 15 a side protrudes to the anode 7 side than the column 15 b side, the base of the electron beam converging unit 3 tilts, and the surface of the electron source 12 moves to the position 26, In contrast, the electron beam 1 is emitted in a direction inclined from the tube axis direction. The electron beam 1 tilted and emitted from the electron source 12 passes through the electron beam converging portion 13 in a tilted state, and then proceeds parallel to the tube axis direction toward the anode 7. The focal point 8 ′ of the electron beam 1 on the target 4 is formed at a position shifted from the original focal point 8 on the target 4 by the amount deflected while passing through the electron beam converging unit 13. Even when the electron beam converging unit 13 is not used, when the electron beam 1 is emitted at an angle from the electron source 12, the focal point 8 ′ is formed at a position shifted from the original focal point 8.

  Further, when the heating element 23b is energized and the column 15b is thermally expanded, the electron source 12 is inclined in the opposite direction to that when the heating element 23a is energized, and the focal point 8 of the electron beam 1 is shown in FIG. It moves in the opposite direction to the focal point 8 ′ shown in FIG.

  As described above, by moving the focal point 8 of the electron beam 1 on the target 4, the target layer 4 a can be used in a wide range by shifting the position where the target layer 4 a is locally worn by the energy concentration of the electron beam. it can. Thereby, the lifetime of the target layer 4a is extended and the X-ray generating tube can be used for a long time.

  In FIG. 1 and FIG. 2, the heating element is brought into contact with each of a plurality of pillars, but either one may be used. In that case, the moving destination of the focal point 8 of the electron beam 1 is only one place.

  Furthermore, the number of pillars may be three or more. In the example shown in FIG. 3, the heating elements 23a to 23d are brought into contact with the four pillars 15a to 15d, respectively, the energization control can be individually performed, and the heating element to be energized is selected, whereby the focal point 8 of the electron beam 1 is selected. It can be shifted more widely. Specifically, by energizing any one of the heating elements 23a to 23d, the focal point 8 of the electron beam 1 can be moved to four locations away from the pillars with which the energized heating element contacts. Also, by energizing two adjacent heating elements such as the heating elements 23a and 23b, 23b and 23c, 23c and 23d, and 23d and 23a, between the focal positions that move when one of them is energized Can be moved.

  Further, in the example of FIGS. 1 to 3, the neck portion 14 is configured by a plurality of pillars, but may be configured by a cylindrical body 31 as illustrated in FIG. 4. In this case, the area | region where the heat generating body 23 of the cylindrical body 31 was contacted, and its vicinity correspond to the deformation | transformation part which concerns on this invention. Moreover, the heat generating body 23 is arrange | positioned in two or more places, and it enables it to supply with electricity separately, The focus 8 of the electron beam 1 can be moved to a wider range.

  Further, FIG. 5 shows an example in which the deformed portion is made of bimetal. In this example, one of the two pillars 15a and 15b is composed of a bimetal 35 composed of a high expansion metal 36 and a low expansion metal 37, and the heating element 23 as control means is brought into contact with the bimetal 35. ing. In such a configuration, when the heating element 23 is energized and the bimetal 35 is heated, as shown in FIG. 6B, the bimetal 35 is curved so as to protrude inward, and the tube of the neck portion 14 on the bimetal 35 side. The axial length is shortened and the surface of the electron source 12 is tilted. As a result, before the electron source 12 is tilted, the focal point 8 was positioned at the center of the target 4 as shown in FIG. 5A. However, when the electron source 12 is tilted, the focus 8 is shown in FIG. Thus, the focal point 8 ′ of the electron beam 1 moves to a position shifted from the center of the target 4.

  5 and 6 show an example in which one of a plurality of pillars is made of a bimetal. However, all of the plurality of pillars are made of a bimetal, and each of them is in contact with a heating element that can be individually controlled for energization. You may let them. In this case, the focal point 8 of the electron beam 1 on the target 4 can be moved in two directions, and the target 4 can be used in a wider range. Further, the bending direction of each bimetal may be reversed, that is, convex outward.

  As another configuration example using a bimetal, as shown in FIG. 7, a configuration in which one of the two pillars 15a and 15b is a deformed portion 15a and the bimetals 35a and 35b are vertically arranged in series. Also mentioned. In this configuration, when the heating element 23 brought into contact with the pillar 15a is energized and heated, the upper and lower bimetals 35a and 35b are curved in the radial direction of the insulating tube 3 as shown in FIG. Arrange them to be in the opposite direction. That is, the radial positions of the high expansion metals 36a and 36b and the low expansion metals 37a and 37b are reversed between the bimetals 35a and 35b. When the heating element 23 is energized in such a configuration and the bimetals 35a and 35b are heated, the upper and lower bimetals 35a and 35b are curved as shown in FIG. 8B, and the length of the column 15a in the tube axis direction is the column 15b. Shorter. As a result, the focal point 8 ′ is formed at a position shifted from the center of the target 4 as shown in FIG. In addition, also about this example, all the several pillars are comprised with a bimetal, the heat generating body which can be individually controlled by electricity is made to contact each, and the focus 8 can be moved to a wider range.

  In the embodiment shown in FIGS. 1 to 8 described above, the focus 8 of the electron beam 1 is moved by tilting the direction of the electron source 12 with respect to the target 4. In the present invention, the same effect can be obtained by moving the electron source 12 in a direction intersecting the longitudinal direction of the neck portion 14, that is, in a direction perpendicular to the tube axis.

  In the embodiment shown in FIG. 9, the neck portion 14 includes a plurality of pillars 15 a and 15 b and a connecting member 39 that connects the plurality of pillars 15 a and 15 b to each other. The pillars 15 a and 15 b are respectively provided with the cathode member 11. Bimetals 35a and 35b are provided on the side. The bimetals 35a and 35b have the same arrangement of the high expansion metals 36a and 36b and the low expansion metals 37a and 37b, respectively, and when the heating elements 23a and 23b are energized and heated simultaneously, they are shown in FIG. As described above, the insulating tube 3 is bent in the same direction in the radial direction. As a result, as the columns 15a and 15b move in the same direction in the radial direction of the insulating tube 3, the electron source 12 also moves in the same direction as the movement direction of the columns 15a and 15b, as shown in FIG. As described above, the focal point 8 ′ is formed at a position shifted from the center of the target 4.

  In the embodiment of FIGS. 1 to 10 described above, the heating element as the control means for controlling the deformation of the deforming portion is shown in contact with the column or the cylindrical body, but the heating element may be attached to the deforming portion. Alternatively, it may be fixed so as to come into contact with the deformed portion by a separate support member (not shown). Moreover, in the said embodiment, although the structure which has arrange | positioned the control means inside the X-ray generator tube was shown, in this invention, a control means can also be arrange | positioned outside.

  FIG. 11 shows a form in which heating elements 23a and 23b are brought into contact with the cathode member 11 outside the X-ray generating tube, and the heating elements 23a and 23b are respectively attached to the cathode members 11 of the columns 15a and 15b of the neck portion 14. Touching position. The heating elements 23a and 23b can be individually energized and controlled. Therefore, the column 15a or 15b is heated by the heating element 23a or 23b via the cathode member 11 and expanded, thereby causing a difference in the length in the tube axis direction between the columns 15a and 15b. Can be tilted.

  Further, the method of deforming the neck portion 14 from the outside is not limited to the heat generator, and as shown in FIG. 12, the radiators 38a and 38b are disposed at the positions where the columns 15a and 15b of the neck portion 14 are attached to the cathode member 11. May be contacted. In this example, the orientation of the electron source 12 with respect to the target 4 is switched by switching the three states of contacting one of the radiators 38 a and 38 b and not contacting both, and the focus of the electron beam 1 on the target 4. The position of 8 can be switched to one of three places.

  In general, an X-ray generating tube is used with a high voltage of about 100 kV applied. In addition, since it generates a large amount of heat, it is installed in insulating oil or gas for electrical insulation and cooling. The electron source 12 usually has a heating filament, and generally emits electrons at a high temperature of about 1000 ° C. Since the inside of the X-ray generator tube is vacuum, the heat generated by the electron source 12 is Then, it is emitted from the surface of the cathode member 8 to the outside through the neck portion 14. Therefore, the radiators 38a and 38b are arranged so as to be in contact with the positions where the pillars 15a and 15b are attached to the cathode member 11, and the focus 8 of the electron beam 1 on the target 4 is changed to three locations by switching the above three states. Can be switched.

  In the embodiment shown in FIGS. 1 to 12, the temperature of the deformed portion of the neck portion 14 is controlled by using a heating element, a heat radiating body, or the like as a control means, and the neck portion 14 is changed depending on the temperature difference between the deformed portion and the region other than the deformed portion. The form which deformed was shown. In this invention, it is not limited to the form which concerns, The form which controls the deformation | transformation of a deformation | transformation part directly with an electrical signal etc. may be sufficient. For example, as shown in FIG. 13, the neck portion 14 includes two pillars 15 a and 15 b, and the end portions on the cathode member 11 side are constituted by piezoelectric elements 41 a and 41 b, thereby forming a deformed portion. . In such a form, the piezoelectric element 41a or 41b is energized from the outside via a wiring (not shown). As a result, the piezoelectric element 41a or 41b is caused to expand and contract along the tube axis direction of the insulating tube 3, and the lengths of the columns 15a and 15b in the tube axis direction are caused to differ from each other in the direction of the electron source 12 with respect to the target 4. Tilt can be caused. The piezoelectric element may be only one of the pillars 15a and 15b, or the number of pillars may be three or more.

  Next, the X-ray generator of the present invention will be described. FIG. 14 is a schematic cross-sectional view showing an example of the configuration of an X-ray generator provided with the X-ray generator tube of the present invention. As shown in FIG. 14, the X-ray generation device 60 of the present invention includes the X-ray generation tube 50 of the present invention and a storage container 52 that stores the X-ray generation tube 50. An insulating fluid 53 is filled.

  A drive circuit 51 including a circuit board (not shown) and an insulating transformer may be provided inside the storage container 52. When the drive circuit 51 is provided, for example, a predetermined voltage signal is applied to the X-ray generation tube 50 from the drive circuit 51, and generation of X-rays can be controlled.

  The storage container 52 only needs to have sufficient strength as a container and is made of metal, plastics material, or the like. The storage container 52 is provided with an X-ray emission window 53 for transmitting X-rays and extracting the X-rays outside the storage container 52. X-rays emitted from the X-ray generation tube 50 are emitted to the outside through the X-ray emission window 53. Glass, aluminum, beryllium or the like is used for the X-ray emission window 53.

  The insulating fluid 54 is preferably an insulating liquid having high electrical insulation, high cooling capacity, and little deterioration due to heat. For example, electrical insulating oil such as silicone oil, transformer oil, and fluorine oil, hydrofluoroether, etc. A fluorine-based insulating liquid or the like can be used.

  Next, an embodiment of the X-ray imaging system according to the present invention will be described with reference to FIG. As shown in FIG. 15, the X-ray generator 60 of the present invention may have a movable aperture unit 55 in the X-ray emission window 53 portion. The movable diaphragm unit 55 has a function of adjusting the width of the irradiation field of the X-ray 2 irradiated from the X-ray generation tube 50. Further, as the movable aperture unit 55, a unit to which a function capable of simulating and displaying the irradiation field of the X-ray 2 with visible light can be used.

  The system control device 62 controls the X-ray generation device 60 and the X-ray detection device 61 in a coordinated manner. The drive circuit 51 outputs various control signals to the X-ray generation tube 50 under the control of the system control device 62. With this control signal, the X-ray 2 emitted from the X-ray generator 60 passes through the subject 64 and is detected by the X-ray detector 66. The X-ray detector 66 converts the detected X-ray into an image signal and outputs it to the signal processing unit 65. The signal processing unit 65 performs predetermined signal processing on the image signal under the control of the system control device 62, and outputs the processed image signal to the system control device 62. The system control device 62 outputs a display signal for displaying an image on the display device 63 to the display device 63 based on the processed image signal. The display device 63 displays an image based on the display signal on the display as a captured image of the subject 64. The X-ray imaging system of the present invention can be used for non-destructive inspection of industrial products and pathological diagnosis of human bodies and animals.

Example 1
The X-ray generating tube shown in FIGS. 1 and 2 was produced. The cathode member 11 and the anode member 6 are formed of a Kovar alloy having a thickness of 5 mm and a thermal expansion coefficient close to that of ceramics, and are joined to an insulating tube 3 made of alumina ceramics having a thickness of 5 mm, an outer diameter of 60 mm, and a length of 110 mm. Hermetically sealed. The inside of the X-ray generation tube was sealed after being evacuated by an exhaust pipe (not shown), and the inside was kept in a vacuum.

  The electron source 12 is an impregnated electron source, and the electron beam converging unit 13 is made of SUS304 stainless alloy, and has a length of 28 mm in the tube axis direction of the insulating tube 3 and an outer diameter of 16 mm. The columns 15a and 15b are made of stainless steel (SUS304). The length of the insulating tube 3 in the tube axis direction is 70 mm, the thickness in the radial direction is 1 mm, the width is 3 mm, and the distance between the radial columns 15a and 15b is 15 mm.

  As the target layer 4a, a tungsten thin film having a thickness of 4 μm was used as a heavy metal having high X-ray radiation efficiency. A polycrystalline artificial diamond substrate having a thickness of 0.6 mm was used as the target support substrate 4b and was bonded to the anode member 6 by brazing. The distance from the electron source 12 to the target 4 was 40 mm.

  The X-ray generator tube is immersed in insulating oil, the acceleration voltage between the cathode 19 and the anode 7 is 100 kV, the potential on the electron emission surface of the electron beam converging unit 13 is 1.8 kV, and X-ray emission driving is performed. It was. When the heating elements 23 a and 23 b brought into contact with the columns 15 a and 15 b were driven without energization, the focal point 8 of the electron beam 1 was positioned at the center of the target 4.

  Next, only the heating element 23a brought into contact with the column 15a was energized, and the average temperature of the column 15a was adjusted to be + 5 ° C. with respect to the column 15b. In this state, it was observed that the column 15a was elongated by about +6 μm with respect to 15b, the tip of the neck portion 14 was tilted, and the focal point 8 ′ of the electron beam 1 was moved 12 μm from the focal point 8 on the target 4. Further, when only the heating element 2b is energized and the average temperature of the column 15b is adjusted to be + 5 ° C. with respect to the column 15a, the tip of the neck portion 14 is inclined in the opposite direction, and the focus of the electron beam 1 is increased. 8 was observed to move 12 μm from the center on the target 4 in the direction opposite to the above.

  In the X-ray generator tube of this example, the size of the focal point 8 of the electron beam 1 on the target 4 is about 7 μm, and by controlling the energization of the heating element, the focal point 8 is moved with a larger moving amount than the focal size. It was possible to move from the center of 4 to two locations in opposite directions. Therefore, the position of the focal point 8 is appropriately changed according to the history of the target layer 4a made of a thin film, and the performance maintenance life of the X-ray generator tube can be extended three times.

  1: electron beam, 2: X-ray, 3: insulating tube, 4: target, 6: anode member, 7: anode, 11: cathode member, 12: electron source, 14: neck portion, 15, 15a, 15b, 15c 15d: pillar, 18: electron gun, 19: cathode, 23, 23a, 23b, 23c, 23d: heating element, 31: cylindrical body, 35, 35a, 35b: bimetal, 38a, 38b: radiator, 39: connection Member, 41a, 41b: piezoelectric element, 50: X-ray generator tube, 54: insulating fluid, 60: X-ray generator, 62: system controller, 64: subject, 66: X-ray detector

Claims (15)

An insulation tube;
An anode comprising: a target that generates X-rays by irradiation of an electron beam; and an anode member that holds the target and is connected to one end of the insulating tube;
A cathode member connected to the other end of the insulating tube; a neck portion having one end connected to the cathode member and an electron source fixed to the other end; and an electron beam emitted from the electron source to the target A cathode having an electron gun for irradiation;
In an X-ray generator tube having
The neck portion has a deformation portion, and the deformation of the deformation portion causes a tilt in the direction of the electron source with respect to the target or moves the position of the electron source in a direction crossing the longitudinal direction of the neck portion. An X-ray generating tube characterized in that   The X-ray generator tube according to claim 1, wherein the deformation of the neck portion is caused by a temperature difference between the deformation portion and a region other than the deformation portion.   The X-ray generation tube according to claim 2, wherein control means for controlling the temperature of the deforming portion is disposed inside the X-ray generation tube.   The neck portion includes a cylindrical body having one end in the axial direction attached to the cathode member, the control means is a heating element that contacts the cylindrical body, and the deformation portion contacts the heating element of the cylindrical body. The X-ray generator tube according to claim 3, wherein the X-ray generator tube is an area and its vicinity.   The neck portion includes a plurality of columns, one end of which is attached to the cathode member, the control means is a heating element that contacts at least one column, and the deforming portion is the column that contacts the heating element. The X-ray generator tube according to claim 3, wherein the X-ray generator tube is provided.   6. The X-ray generating tube according to claim 5, wherein the control means is arranged for each column and can be individually energized.   The X-ray generating tube according to claim 5, wherein the deformable portion is made of a bimetal.   The X-ray generating tube according to claim 5 or 6, wherein the deforming portion is made of two bimetals arranged in series so that the bending directions are opposite to each other in the radial direction of the insulating tube.   The neck portion includes a plurality of pillars, one end of which is attached to the cathode member, and a connecting portion that connects the plurality of columns to each other, and the deforming portion is provided at one end where each column is connected to the cathode member. The deforming portion is made of a bimetal arranged such that the bending direction is the same in all the columns in the radial direction of the insulating tube, and the control means is a heating element that contacts the deforming portion. The X-ray generator tube according to claim 3.   The X-ray generation tube according to claim 2, wherein control means for controlling the temperature of the deforming portion is disposed outside the X-ray generation tube.   The neck portion includes a plurality of pillars, one end of which is attached to the cathode member, and the control means is located outside at least one of the positions where the pillar is attached to the cathode member. The X-ray generating tube according to claim 10, wherein the X-ray generator tube is a heating element that contacts, and the deforming portion is the column having one end at a position where the heating element contacts via the cathode member.   The neck portion includes a plurality of pillars, one end of which is attached to the cathode member, and the control means is located outside at least one of the positions where the pillar is attached to the cathode member. The X-ray generator tube according to claim 10, wherein the X-ray generator tube is a contactable heat radiator, and the deforming portion is the column having one end at a position where the heat radiator can contact via the cathode member.   The neck portion includes a plurality of pillars having one end attached to the cathode member, and the deformable portion is a piezoelectric element disposed at one end connected to the cathode member of at least one pillar. The X-ray generator tube according to claim 1.   An X-ray generation tube according to any one of claims 1 to 13, a storage container storing the X-ray generation tube, and an insulating fluid filled in an extra space inside the storage container. An X-ray generator characterized by that. X-ray generator according to claim 14,
An X-ray detector that detects X-rays generated from the X-ray generator and transmitted through the subject;
An X-ray imaging system comprising: a system control device that controls the X-ray generation device and the X-ray detector in a coordinated manner.

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