X-ray generation device, x-ray imaging device, and method for adjusting x-ray generation device

Abstract

An X-ray generating apparatus includes: an X-ray generating tube including an electron gun and a target configured to generate X-rays upon receiving an electron beam emitted from the electron gun; a deflector that deflects the electron beam; a drive circuit that applies an acceleration voltage between the cathode of the electron gun and the target; and an adjustment unit for adjusting, in accordance with the acceleration voltage or the amount of change in the acceleration voltage, the deflection of the electron beam by the deflector so as to reduce the change in the incident position of the electron beam on the target due to the change in the acceleration voltage.

Description

Technical Field

[0001] The present invention relates to an X-ray generating device, an X-ray imaging device and an adjustment method of the X-ray generating device. Background Art

[0002] In a transmission-type X-ray tube, an electron beam is irradiated onto a target, thereby emitting X-rays from the target. The electron beam generated at the cathode is accelerated by an acceleration voltage and irradiated onto the target. When this acceleration voltage is changed, the energy of the electron beam that strikes the target changes. Patent document 1 describes a transmission-type X-ray tube device having: an X-ray transmission window; a metal film that forms an X-ray target disposed on the vacuum side of the X-ray transmission window; an electron gun that generates an electron beam; and a deflection electrode that deflects the electron beam. The metal film has a gradually changing thickness. In this X-ray tube device, an electron beam is irradiated at a point where the thickness of the metal film is consistent with the depth into which the electrons enter. This operation is achieved in the following manner: the deflection voltage applied to the deflection electrode is changed according to the acceleration voltage of the electron beam generated by the electron gun.

[0003] In an X-ray imaging device integrated with an X-ray generator, the acceleration voltage can be changed in order to change the energy or energy distribution of the X-rays generated by the X-ray generator. However, if the incident position of the electron beam on the target changes according to the change in the acceleration voltage, the generation position of the X-rays, that is, the focal position of the X-ray imaging device, changes accordingly. Therefore, each time the acceleration voltage is changed, the position of the X-ray detector (for detecting the X-rays emitted from the X-ray generator) needs to be adjusted.

[0004] Prior Art Literature

[0005] [Patent Document]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2001-126650 Summary of the invention

[0007] The present invention can provide a technique that is useful for reducing the change in the generation position of X-rays due to a change in the acceleration voltage.

[0008] The first aspect of the present invention relates to an X-ray generating device, comprising: an X-ray generating tube, which includes an electron gun and a target configured to generate X-rays upon receiving an electron beam emitted from the electron gun; a deflector configured to deflect the electron beam; a drive circuit configured to apply an acceleration voltage between a cathode of the electron gun and the target; and an adjustment unit configured to adjust the deflection of the electron beam caused by the deflector to reduce the change in the incident position of the electron beam on the target caused by the change in the acceleration voltage, depending on the acceleration voltage or the amount of change in the acceleration voltage.

[0009] A second aspect of the present invention relates to an X-ray imaging device, comprising: an X-ray generating device as described in the first aspect; and an X-ray detector configured to detect X-rays emitted from the X-ray generating device.

[0010] The third aspect of the present invention relates to an adjustment method for an X-ray generating device, wherein the X-ray generating device comprises: an X-ray generating tube, which includes an electron gun and a target configured to generate X-rays upon receiving an electron beam emitted from the electron gun; a deflector, which is configured to deflect the electron beam; and a drive circuit, which is configured to apply an acceleration voltage between a cathode of the electron gun and the target; the adjustment method comprises the following steps: based on the acceleration voltage or the amount of change in the acceleration voltage, adjusting the deflection of the electron beam caused by the deflector to reduce the change in the incident position of the electron beam on the target caused by the change in the acceleration voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a diagram schematically showing a cross-sectional structure near the center of an X-ray generating tube according to an embodiment.

[0012] Figure 2 This is a diagram schematically showing how an electron beam emitted from an electron gun strikes a target.

[0013] Figure 3 It is a diagram for explaining a first configuration example of the X-ray generating device.

[0014] Figure 4 It is a figure for demonstrating the 1st - 4th structural example of an X-ray generation device.

[0015] Figure 5 It is a diagram for explaining a first configuration example of the X-ray generating device.

[0016] Figure 6 It is a figure for demonstrating the 1st - 4th structural example of an X-ray generation device.

[0017] Figure 7 It is a diagram for explaining a first configuration example of the X-ray generating device.

[0018] Figure 8 It is a figure for demonstrating the 1st - 4th structural example of an X-ray generation device.

[0019] Fig. 9 It is a diagram for explaining a second configuration example of the X-ray generating device.

[0020] Fig.10 It is a diagram for explaining a second configuration example of the X-ray generating device.

[0021] Fig.11 It is a diagram for explaining a second configuration example of the X-ray generating device.

[0022] Fig.12 It is a diagram for explaining a third configuration example of the X-ray generating device.

[0023] Fig.13 It is a diagram for explaining a third configuration example of the X-ray generating device.

[0024] Fig.14 It is a diagram for explaining a third configuration example of the X-ray generating device.

[0025] Fig.15 It is a diagram for explaining a fourth configuration example of the X-ray generating device.

[0026] Fig.16 It is a diagram for explaining a fourth configuration example of the X-ray generating device.

[0027] Fig.17 It is a diagram for explaining the fifth configuration example of the X-ray generating device.

[0028] Fig.18 This is a block diagram illustrating the structure of an X-ray generating device according to an embodiment.

[0029] Fig.19 A block diagram illustrating the configuration of an X-ray imaging device according to an embodiment. DETAILED DESCRIPTION

[0030] The following detailed description of the embodiments is made with reference to the accompanying drawings. In addition, the following embodiments are not intended to limit the scope of the present invention. In the embodiments, although multiple features are described, it is not limited to that all of these multiple features are essential to the invention; in addition, multiple of these features can also be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference symbols are marked for the same or similar structures, and their repeated descriptions are omitted.

[0031] At Figure 1, schematically shows a cross-sectional structure near the center of an X-ray generating tube XG of an embodiment. The X-ray generating device 1 can be configured as a transmission type X-ray generating device. The X-ray generating device 1 includes an X-ray generating tube XG. The X-ray generating tube XG can include an electron gun EG, and can include a target 22 that receives an electron beam EB or electrons emitted from the electron gun EG to generate X-rays. In one example, the X-ray generating tube XG can include: an insulating tube 10 having two open ends; an anode 20 that closes one of the two open ends of the insulating tube 10; and a closing member 30 that closes the other of the two open ends of the insulating tube 10. The anode 20 can include: a target 22; a target holding plate 21 that holds the target 22; and an electrode 23 that supports the target holding plate 21 and provides a potential to the target 22 via the target holding plate 21. The anode 20 can be maintained at a ground potential, for example. The closing member 30 can be configured to hold the electron gun EG. The insulating tube 10, the anode 20 and the closing member 30 may constitute a container defining a closed space. The closed space may be maintained at a vacuum or a high vacuum.

[0032] The electron gun EG may include: a cathode CT; an extraction electrode EE disposed between the cathode CT and the anode 20; and a convergence electrode CE disposed between the extraction electrode EE and the anode 20. The cathode CT emits electrons. An accelerating voltage is supplied between the cathode CT and the anode 20. The amount of electrons incident on the target 22 of the anode 20 per unit time (i.e., current) is called a tube current, which may depend on the extraction potential supplied to the extraction electrode EE. The convergence electrode CE converges the electrons or electron beams emitted from the cathode CT. The convergence electrode CE may include a plurality of electrodes.

[0033] The X-ray generating device 1 may include a cathode potential supply unit 41 for supplying a cathode potential to the cathode CT. The cathode potential supply unit 41 may also be understood as a driving circuit that supplies an acceleration voltage between the anode 20 that can be maintained at a ground potential and the cathode CT. The X-ray generating device 1 may include an extraction potential supply unit 42 for supplying an extraction potential to the extraction electrode EE. The extraction potential supply unit 42 may also be understood as a component that supplies the extraction potential between the cathode CT and the extraction electrode EE. The X-ray generating device 1 may include a convergence potential supply unit 43 for supplying a convergence potential to the convergence electrode CE. The convergence potential supply unit 43 may be understood as a component that supplies a convergence voltage between the cathode CT and the convergence electrode CE.

[0034] The X-ray generating device 1 may further include a deflector 50 for deflecting the electron beam EB emitted from the electron gun EG. The deflector 50 may be arranged outside the X-ray generating tube XG. The deflector 50 may be arranged, for example, so that a virtual plane VP3 is located between the virtual plane VP1 and the virtual plane VP2, the virtual plane VP3 crosses the deflector 50, the virtual plane VP1 includes the electron beam incident surface of the target 22 (the surface facing the electron gun EG), and the virtual plane VP2 includes the top surface of the electron gun EG (the surface on the target 22 side). The virtual planes VP1, VP2, and VP3 may be defined as planes that intersect perpendicularly with the central axis AX of the electron gun EG. The deflector 50 applies a magnetic field to the electron beam EB emitted from the electron gun EG, thereby deflecting the electron beam EB. The amount by which the deflector 50 deflects the electron beam EB may depend on the acceleration voltage.

[0035] The deflector 50 may be formed of a permanent magnet, an electromagnet, or a permanent magnet and an electromagnet. In one example, the deflector 50 may include a first magnet and a second magnet. The first magnetic pole (e.g., S pole) of the first magnet and the second magnetic pole (e.g., N pole) of the second magnet may be arranged to face each other across the insulating tube 10 or the X-ray generating tube XG. The deflector 50 may also be formed of a single magnet, and the single magnet may be arranged such that the magnetic pole faces the radial direction of the insulating tube 10 or the X-ray generating tube XG.

[0036] The electrode 23 is electrically connected to the target 22 and provides a potential to the target 22. The target 22 generates X-rays when the electrons from the electron gun EG hit the target 22. The X-rays generated by the target 22 pass through the target holding plate 21 and are radiated to the outside of the X-ray generating tube XG. The anode 20 can be maintained at a ground potential, for example, but can also be maintained at other potentials. The target 22 is made of a metal material. The target 22 is preferably made of a material with a high melting point, such as tungsten, tantalum or molybdenum. These materials are advantageous in order to improve the efficiency of X-ray generation. The target holding plate 21 can be made of a material that allows X-rays to pass easily, such as beryllium, diamond, etc.

[0037] The X-ray generating device 1 may include an adjustment unit 60 for adjusting the deflection of the electron beam EB caused by the deflector 50 according to the acceleration voltage or the amount of change in the acceleration voltage, thereby reducing the change in the incident position of the electron beam EB on the target 22 caused by the change in the acceleration voltage. In this case, the acceleration voltage, as described above, is a voltage supplied between the anode 20 and the cathode CT by the cathode potential supply unit 41. In the absence of the adjustment unit 60, when the acceleration voltage changes, the amount of deflection of the electron beam EB emitted from the electron gun EG due to the deflector 50 changes, and accordingly, the incident position of the electron beam EB on the target 22 may change. When the incident position of the electron beam EB on the target 22 changes due to the change in the acceleration voltage, the generation position of the X-ray changes in the X-ray imaging device that integrates the X-ray generating device 1 and the X-ray detector, that is, the focal position changes. This change in the focal position may require readjustment of the X-ray imaging device (for example, positioning of the X-ray detector relative to the X-ray generating device). Therefore, the X-ray generator 1 of this embodiment includes an adjustment unit 60 for reducing the change in the incident position of the electron beam on the target 22 due to the change in the acceleration voltage. The incident position of the electron beam on the target 22 is a position on a plane (virtual plane VP1) perpendicular to the central axis AX of the electron gun EG.

[0038] When the deflector 50 includes a magnet (permanent magnet and / or electromagnet), the adjustment unit 60 may include an adjustment mechanism for adjusting the position of the magnet. The adjustment mechanism is a mechanical adjustment mechanism for adjusting the position of the magnet, and may include, for example, an actuator for driving the deflector 50. The adjustment mechanism may also include a guide portion for guiding the deflector 50. The adjustment mechanism may also include a fixing mechanism (for example, a screw, a spring) for fixing the deflector 50. The adjustment unit 60 may control the position of the magnet according to the acceleration voltage or the amount of change in the acceleration voltage, thereby reducing the change in the incident position of the electron beam EB on the target 22 caused by the change in the acceleration voltage. The control of the position of the magnet by the adjustment unit 60 may include controlling the position of the magnet in a direction parallel to the central axis AX of the electron gun EG. Alternatively, the control of the position of the magnet by the adjustment unit 60 may include controlling the distance between the straight line including the central axis of the electron gun EG and the magnet. Alternatively, the control of the position of the magnet by the adjustment unit 60 may include controlling the position of the magnet in a direction parallel to the central axis AX of the electron gun EG, and may include controlling the distance between the magnet and a straight line including the central axis of the electron gun EG. Alternatively, the adjustment unit 60 may control the rotation angle of the magnet according to the acceleration voltage or the amount of change in the acceleration voltage, thereby reducing the change in the incident position of the electron beam EB on the target 22 caused by the change in the acceleration voltage. The adjustment of the rotation angle of the magnet by the adjustment unit 60 may include adjusting the rotation angle of the magnet around an axis perpendicular to the central axis AX of the electron gun EG. In the case where the deflector 50 includes an electromagnet, the adjustment unit 60 may also be configured to adjust the magnetic field (for example, the strength of the magnetic field) generated by the electromagnet according to the acceleration voltage or the amount of change in the acceleration voltage.

[0039] At Figure 2 , schematically showing the manner in which the electron beam EB emitted from the electron gun EG hits the target 22. Figure 2 , the electron gun EG and the target 22 are shown to be close to each other, but the electron gun EG and the target 22 may be configured to be further apart. The electron beam EB emitted from the electron gun EG is incident on or hits the target 22 after being deflected by the magnetic field generated by the deflector 50. The amount by which the electron beam EB is deflected, in other words, the incident position of the electron beam EB on the target 22 may depend on the magnetic field and the acceleration voltage generated by the deflector 50 and acting on the electron beam EB.

[0040] When the magnetic field (intensity and direction) generated by the deflector 50 and acting on the electron beam EB is fixed, when the acceleration voltage changes, the incident position of the electron beam EB on the target 22 changes according to the change in the acceleration voltage. Conversely, when the magnetic field (intensity and direction) generated by the deflector 50 and acting on the electron beam EB changes under the condition of the acceleration voltage being fixed, the incident position of the electron beam EB on the target 22 changes according to the change in the magnetic field. The adjustment unit 60 adjusts the magnetic field applied to the electron beam EB by the deflector 50 according to the acceleration voltage or the amount of change in the acceleration voltage, thereby adjusting the deflection of the electron beam EB caused by the deflector 50, thereby reducing the change in the incident position of the electron beam on the target 22 caused by the change in the acceleration voltage.

[0041] At Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , showing a first configuration example of the X-ray generating device 1. Figure 3 , Figure 4 , schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is a first voltage V1, and the electron beam EB is adjusted to a first state by the adjustment unit 60. The deflector 50 may be composed of a pair of magnets arranged opposite to each other with the central axis AX sandwiched therebetween. Each magnet may be a permanent magnet, an electromagnet, or a composite of a permanent magnet and an electromagnet. The adjustment unit 60 may include an adjustment mechanism for adjusting the position of the magnet serving as the deflector 50. The adjustment mechanism may include an actuator (e.g., a motor) 63 for driving the deflector 50. The adjustment unit 60 may include an adapter (holder) 61 for holding the deflector 50 as the adjustment mechanism. In this case, the actuator 63 may be configured to drive the deflector 50 by driving the adapter 61. The adjustment mechanism may also include a guide unit 62 for guiding the deflector 50 or the adapter 61. The adjustment unit 60 can be operated or controlled so that the position of the magnet as the deflector 50 is adjusted according to the acceleration voltage or the amount of change in the acceleration voltage. In the first configuration example, the control of the position of the magnet by the adjustment unit 60 includes the adjustment of the position of the magnet in a direction parallel to the central axis AX of the electron gun EG.

[0042] In the Figure 3 , Figure 4 In the state of , the electron beam EB emitted from the electron gun EG is incident on the first position P1 of the target 22. Figure 5 , Figure 6, schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the first state by the adjustment unit 60. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. In addition, the acceleration voltage can be determined as a value obtained by subtracting the potential of the cathode CT from the potential of the anode 20, that is, a positive value, or can be determined as a value obtained by subtracting the potential of the anode 20 from the potential of the cathode CT, that is, a negative value. Figure 5 , Figure 6 In the state of , the electron beam EB emitted from the electron gun EG is incident on the second position P2 of the target 22. The second position P2 is closer to the straight line including the central axis AX of the electron gun EG than the first position P1. That is, the distance between the second position P2 and the straight line including the central axis AX is smaller than the distance between the first position P1 and the straight line including the central axis AX.

[0043] At Figure 7 , Figure 8 , schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the second state by the adjustment unit 60. The adjustment of the electron beam EB to the second state by the adjustment unit 60 preferably refers to the following state: the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB on the target 22 is the first position P1. The adjustment unit 60 is in the second state, which refers to the following state: the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the acceleration voltage Va (= V2) or the amount of change in the acceleration voltage (= V1-V2) to reduce the change in the incident position of the electron beam EB on the target 22 caused by the change of the acceleration voltage Va from the first voltage V1 to the second voltage V2 (that is, the change from the first position P1 to the second position P2).

[0044] The adjustment of the deflection of the electron beam EB by the adjustment unit 60 as described above can be understood as maintaining the incident position of the electron beam EB on the target 22 within the target region regardless of the change of the acceleration voltage Va. The target region preferably has a diameter that is 3 times or less of the diameter of the electron beam EB on the target 22. The adjustment by the adjustment unit 60 is performed by setting the target region in this way, so that it is not necessary to position the X-ray detector according to the acceleration voltage for the X-ray generating device.

[0045] In the first configuration example, when the acceleration voltage Va is changed in the direction in which the absolute value of the acceleration voltage Va increases, the adjustment unit 60 adjusts the position of the deflector 50 in the direction parallel to the straight line including the central axis AX in the direction in which the deflector 50 moves away from the target 22. On the other hand, in the first configuration example, when the acceleration voltage Va is changed in the direction in which the absolute value of the acceleration voltage Va decreases, the adjustment unit 60 adjusts the position of the deflector 50 in the direction parallel to the straight line including the central axis AX in the direction in which the deflector 50 approaches the target 22.

[0046] The position of the deflector 50 can be adjusted according to the acceleration voltage Va or the amount of change in the acceleration voltage. For example, the relationship between the magnitude of the acceleration voltage Va or the amount of change in the acceleration voltage and the appropriate position of the deflector 50 for causing the electron beam EB to be incident on the target area of ​​the target 22 can be determined in advance through experiments or calculations, and the adjustment is performed based on the relationship. Alternatively, the position of the deflector 50 can be adjusted according to the acceleration voltage Va or the amount of change in the acceleration voltage by using an X-ray detector or the like to monitor the incident position of the electron beam EB on the target 22, and adjusting the position of the deflector 50 by the adjustment unit 60 so that the electron beam EB is incident on the target area of ​​the target 22.

[0047] At Fig. 9 , Fig.10 , Fig.11 , Figure 4 , Figure 6 , Figure 8 , showing a second configuration example of the X-ray generating device 1. Fig. 9 , Figure 4, schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is a first voltage V1, and the electron beam EB is adjusted to a first state by the adjustment unit 60. The deflector 50, for example, can be composed of a pair of magnets arranged opposite to each other with the central axis AX sandwiched therebetween. Each magnet can be a permanent magnet, an electromagnet, or a composite of a permanent magnet and an electromagnet. The adjustment unit 60 can include an adjustment mechanism for adjusting the position of the magnet serving as the deflector 50. The adjustment mechanism can include an actuator (for example, a motor) 66 for driving the deflector 50. The adjustment mechanism can include an adapter (holder) 64 for holding the deflector 50. In this case, the actuator 66 can be configured to drive the deflector 50 by driving the adapter 64. The adjustment mechanism can also include a guide unit 65 for guiding the deflector 50 or the adapter 64. The adjustment unit 60 can be operated or controlled so that the position of the magnet of the deflector 50 is adjusted according to the acceleration voltage or the amount of change in the acceleration voltage. In the second configuration example, the control of the position of the magnet by the adjustment unit 60 includes the adjustment of the position of the magnet in the direction parallel to the distance between the straight line including the center axis AX of the electron gun EG and the magnet. The second configuration example can also be combined with the first configuration example. That is, the control of the position of the magnet by the adjustment unit 60 can include the adjustment of the position of the magnet in the direction parallel to the center axis AX of the electron gun EG, and can include the adjustment of the distance between the straight line including the center axis AX of the electron gun EG and the magnet.

[0048] In the Fig. 9 , Figure 4 In the state of , the electron beam EB emitted from the electron gun EG is incident on the first position P1 of the target 22. Fig.10 , Figure 6 , schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the first state by the adjustment unit 60. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. Fig.10 , Figure 6 In the state of , the electron beam EB emitted from the electron gun EG is incident on the second position P2 of the target 22. The second position P2 is closer to the straight line including the central axis AX of the electron gun EG than the first position P1. That is, the distance between the second position P2 and the straight line including the central axis AX is smaller than the distance between the first position P1 and the straight line including the central axis AX.

[0049] At Fig.11 , Figure 8, schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the second state by the adjustment unit 60. The adjustment of the electron beam EB to the second state by the adjustment unit 60 preferably refers to the following state: the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB on the target 22 is the first position P1. The adjustment unit 60 is in the second state, which refers to the following state: the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the acceleration voltage Va (= V2) or the amount of change in the acceleration voltage (= V1-V2) to reduce the change in the incident position of the electron beam EB on the target 22 caused by the change of the acceleration voltage Va from the first voltage V1 to the second voltage V2 (that is, the change from the first position P1 to the second position P2).

[0050] The adjustment of the deflection of the electron beam EB by the adjustment unit 60 as described above can be understood as maintaining the incident position of the electron beam EB on the target 22 within the target region regardless of changes in the acceleration voltage Va. The target region preferably has a diameter that is less than or equal to three times the diameter of the electron beam EB on the target 22.

[0051] In the second configuration example, when the acceleration voltage Va is changed in the direction in which the absolute value of the acceleration voltage Va increases, the adjustment unit 60 adjusts the position of the deflector 50 so that the deflector 50 approaches the straight line including the central axis AX. On the other hand, in the second configuration example, when the acceleration voltage Va is changed in the direction in which the absolute value of the acceleration voltage Va decreases, the adjustment unit 60 adjusts the position of the deflector 50 so that the deflector 50 moves away from the straight line including the central axis AX.

[0052] The adjustment of the position of the deflector 50 according to the acceleration voltage Va or the amount of change in the acceleration voltage can be performed based on the relationship between the magnitude of the acceleration voltage Va or the amount of change in the acceleration voltage and the appropriate position of the deflector 50 for causing the electron beam EB to be incident on the target area of ​​the target 22, which can be obtained in advance through experiments or calculations. Alternatively, the adjustment of the position of the deflector 50 according to the acceleration voltage Va or the amount of change in the acceleration voltage can be performed in the following manner: while monitoring the incident position of the electron beam EB on the target 22 using an X-ray detector or the like, the position of the deflector 50 is adjusted by the adjustment unit 60 so that the electron beam EB is incident on the target area of ​​the target 22.

[0053] At Fig.12 , Fig.13 , Fig.14 , Figure 4 , Figure 6 , Figure 8 , showing a third configuration example of the X-ray generating device 1. Fig.12 , Figure 4, schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is a first voltage V1, and the electron beam EB is adjusted to a first state by the adjustment unit 60. The deflector 50 may be composed of a pair of magnets arranged opposite to each other with the central axis AX sandwiched therebetween. Each magnet may be a permanent magnet, an electromagnet, or a composite of a permanent magnet and an electromagnet. The adjustment unit 60 may include an adjustment mechanism for adjusting the position of the magnet serving as the deflector 50. The adjustment mechanism may include an actuator (e.g., a motor) 69 for driving the deflector 50. The adjustment mechanism may include an adapter (holder) 67 for holding the deflector 50. In this case, the actuator 69 may be configured to drive the deflector 50 by driving the adapter 67. The adjustment mechanism may also include a guide unit 68 for guiding the deflector 50 or the adapter 67. The adjustment unit 60 can be operated or controlled so that the rotation angle of the magnet as the deflector 50 is adjusted according to the acceleration voltage or the amount of change in the acceleration voltage. The control of the rotation angle of the magnet by the adjustment unit 60 can include adjusting the rotation angle of the magnet around the axis perpendicular to the central axis AX of the electron gun EG. The third configuration example can be used in combination with at least one of the first and second configuration examples.

[0054] In the Fig.12 , Figure 4 In the state of , the electron beam EB emitted from the electron gun EG is incident on the first position P1 of the target 22. Fig.13 , Figure 6 , schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the first state by the adjustment unit 60. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. Fig.13 , Figure 6 In the state of , the electron beam EB emitted from the electron gun EG is incident on the second position P2 of the target 22. The second position P2 is closer to the straight line including the central axis AX of the electron gun EG than the first position P1. That is, the distance between the second position P2 and the straight line including the central axis AX is smaller than the distance between the first position P1 and the straight line including the central axis AX.

[0055] At Fig.14 , Figure 8, schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the second state by the adjustment unit 60. The adjustment of the electron beam EB to the second state by the adjustment unit 60 preferably refers to the following state: the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB on the target 22 is the first position P1. The adjustment unit 60 is in the second state, which refers to the following state: the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the acceleration voltage Va (= V2) or the amount of change in the acceleration voltage (= V1-V2) to reduce the change in the incident position of the electron beam EB on the target 22 caused by the change of the acceleration voltage Va from the first voltage V1 to the second voltage V2 (that is, the change from the first position P1 to the second position P2).

[0056] The adjustment of the deflection of the electron beam EB by the adjustment unit 60 as described above can be understood as maintaining the incident position of the electron beam EB on the target 22 within the target region regardless of changes in the acceleration voltage Va. The target region preferably has a diameter that is less than or equal to three times the diameter of the electron beam EB on the target 22.

[0057] In the third configuration example, when the acceleration voltage Va is changed in the direction of increasing the absolute value of the acceleration voltage Va, the adjustment unit 60 adjusts the rotation angle of the deflector 50 so that the magnetic field acting on the vertical component of the electron beam EB becomes stronger. On the other hand, in the third configuration example, when the acceleration voltage Va is changed in the direction of decreasing the absolute value of the acceleration voltage Va, the adjustment unit 60 adjusts the rotation angle of the deflector 50 so that the magnetic field acting on the vertical component of the electron beam EB becomes weaker.

[0058] The adjustment of the rotation angle of the deflector 50 according to the acceleration voltage Va or the amount of change in the acceleration voltage can be performed based on, for example, the relationship between the magnitude of the acceleration voltage Va or the amount of change in the acceleration voltage and the appropriate rotation angle of the deflector 50 for causing the electron beam EB to be incident on the target area of ​​the target 22, which can be obtained in advance through experiments or calculations. Alternatively, the adjustment of the rotation angle of the deflector 50 according to the acceleration voltage Va or the amount of change in the acceleration voltage can be performed in the following manner: while monitoring the incident position of the electron beam EB on the target 22 using an X-ray detector or the like, the rotation angle of the deflector 50 is adjusted by the adjustment unit 60 so that the electron beam EB is incident on the target area of ​​the target 22.

[0059] At Fig.15 , Fig.16 , Fig.17 , Figure 4 , Figure 6 , Figure 8 , showing a fourth configuration example of the X-ray generating device 1. Fig.15 , Figure 4 , schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is a first voltage V1, and the electron beam EB is adjusted to a first state by the adjustment unit 60. The deflector 50 can be composed of a pair of magnets arranged opposite to each other with the central axis AX sandwiched therebetween. Each magnet includes at least an electromagnet. The adjustment unit 60 can be configured to control the current supplied to the electromagnet constituting the deflector 50. The adjustment unit 60 can be configured to adjust the magnetic field generated by the electromagnet constituting the deflector 50 according to the acceleration voltage or the amount of change in the acceleration voltage. The adjustment unit 60 can control the current supplied to the electromagnet constituting the deflector 50 according to the acceleration voltage. The fourth configuration example can be used in combination with at least one of the first to third configuration examples.

[0060] In the Fig.15 , Figure 4 In the state of , the electron beam EB emitted from the electron gun EG is incident on the first position P1 of the target 22. Fig.16 , Figure 6 , schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the first state by the adjustment unit 60. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. Fig.16 , Figure 6 In the state of , the electron beam EB emitted from the electron gun EG is incident on the second position P2 of the target 22. The second position P2 is closer to the straight line including the central axis AX of the electron gun EG than the first position P1. That is, the distance between the second position P2 and the straight line including the central axis AX is smaller than the distance between the first position P1 and the straight line including the central axis AX.

[0061] At Fig.17 , Figure 8 , schematically shows an X-ray generating device 1, wherein the acceleration voltage Va is the second voltage V2, and the electron beam EB is adjusted to the second state by the adjustment unit 60. The adjustment of the electron beam EB to the second state by the adjustment unit 60 preferably refers to the following state: the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB on the target 22 is the first position P1. The adjustment unit 60 is in the second state, which refers to the following state: the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the acceleration voltage Va (= V2) or the amount of change in the acceleration voltage (= V1-V2) to reduce the change in the incident position of the electron beam EB on the target 22 caused by the change of the acceleration voltage Va from the first voltage V1 to the second voltage V2 (that is, the change from the first position P1 to the second position P2).

[0062] The adjustment of the deflection of the electron beam EB by the adjustment unit 60 as described above can be understood as maintaining the incident position of the electron beam EB on the target 22 within the target region regardless of changes in the acceleration voltage Va. The target region preferably has a diameter that is less than or equal to three times the diameter of the electron beam EB on the target 22.

[0063] In the fourth configuration example, when the acceleration voltage Va is changed in the direction of increasing the absolute value of the acceleration voltage Va, the adjustment unit 60 increases the magnitude of the current supplied to the electromagnet constituting the deflector 50. On the other hand, in the fourth configuration example, when the acceleration voltage Va is changed in the direction of decreasing the absolute value of the acceleration voltage Va, the adjustment unit 60 decreases the magnitude of the current supplied to the electromagnet constituting the deflector 50.

[0064] The adjustment of the position of the deflector 50 according to the acceleration voltage Va or the amount of change in the acceleration voltage can be performed based on, for example, the relationship between the magnitude of the acceleration voltage Va or the amount of change in the acceleration voltage and the magnitude of the current supplied to the deflector 50 in order to make the electron beam EB incident on the target area of ​​the target 22, which can be obtained in advance through experiments or calculations. Alternatively, the adjustment of the position of the deflector 50 according to the acceleration voltage Va or the amount of change in the acceleration voltage can be performed in the following manner: while monitoring the incident position of the electron beam EB on the target 22 using an X-ray detector or the like, the current supplied from the adjustment unit 60 to the deflector 50 is adjusted so that the electron beam EB is incident on the target area of ​​the target 22.

[0065] At Fig.18 , shows the structure of an X-ray generating device 1 according to an embodiment. The X-ray generating device 1 may include a boost circuit 110 and a drive circuit 120 in addition to the above-mentioned X-ray generating tube XG. The boost circuit 110 may generate a boosted voltage by boosting a voltage supplied from the outside, and supply the boosted voltage to the drive circuit 120. The drive circuit 120 may drive the X-ray generating tube XG based on the boosted voltage supplied from the boost circuit 110. The drive circuit 120 may include the above-mentioned cathode potential supply unit 41, extraction potential supply unit 42, and convergence potential supply unit 43.

[0066] At Fig.19, shows the structure of an X-ray imaging device 200 according to an embodiment. The X-ray imaging device 200 may include an X-ray generating device 1, and may include an X-ray detecting device 240 for detecting X-rays XR emitted from the X-ray generating device 1 and transmitted through an object 230. The X-ray detecting device 240 may further include a control device 210 and a display device 220. The X-ray detecting device 240 may include an X-ray detector 242 and a signal processing unit 244. The control device 210 may control the X-ray generating device 1 and the X-ray detecting device 240. The X-ray detector 242 may detect or image the X-rays XR emitted from the X-ray generating device 1 and transmitted through the object 230. The signal processing unit 244 may process a signal output from the X-ray detector 242, and supply the processed signal to the control device 210. The control device 210 displays an image on the display device 220 based on the signal supplied from the signal processing unit 244. The control device 210 can control the adjustment unit 60 to reduce the change in the incident position of the electron beam EB on the target 22 due to the change in the acceleration voltage, depending on the acceleration voltage or the amount of change in the acceleration voltage.

[0067] Explanation of symbols

[0068] 1: X-ray generating device, XG: X-ray generating tube, EG: electron gun, CT: cathode electrode, EE: extraction electrode, CE: convergence electrode, EB: electron beam, 20: anode, 21: target holding plate, 22: target, 23: electrode, 50: deflector, 60: adjustment unit, AX: center axis.

Claims

1. An X-ray generating device, comprising: An X-ray generating tube including an electron gun and a target configured to generate X-rays upon receiving an electron beam emitted from the electron gun; a deflector configured to deflect the electron beam; a drive circuit configured to apply an accelerating voltage between a cathode of the electron gun and the target; as well as An adjustment unit is configured to adjust the deflection of the electron beam caused by the deflector according to the acceleration voltage or the amount of change in the acceleration voltage so as to reduce the change in the incident position of the electron beam on the target due to the change in the acceleration voltage.

2. The X-ray generating device according to claim 1, wherein: The deflector comprises a magnet, and The adjustment unit includes an adjustment mechanism configured to adjust the position of the magnet.

3. The X-ray generating device according to claim 2, wherein: The adjustment unit controls the position of the magnet according to the acceleration voltage so as to reduce a change in an incident position of the electron beam on the target due to a change in the acceleration voltage.

4. The X-ray generating device according to claim 2 or 3, wherein: The adjustment of the position of the magnet by the adjustment unit includes adjustment of the position of the magnet in a direction parallel to the central axis of the electron gun.

5. The X-ray generating device according to claim 2 or 3, wherein: The adjustment of the position of the magnet by the adjustment unit includes adjusting the distance between the magnet and a straight line including the central axis of the electron gun.

6. The X-ray generating device according to claim 2 or 3, wherein: Controlling the position of the magnet by the adjustment unit includes adjusting the position of the magnet in a direction parallel to the central axis of the electron gun and adjusting the distance between the magnet and a straight line including the central axis of the electron gun.

7. The X-ray generating device according to claim 2, wherein: The adjustment unit controls the rotation angle of the magnet according to the acceleration voltage or the amount of change in the acceleration voltage so as to reduce a change in an incident position of the electron beam on the target due to a change in the acceleration voltage.

8. The X-ray generating device according to claim 7, wherein: The adjustment of the rotation angle of the magnet by the adjustment unit includes adjustment of the rotation angle of the magnet around an axis perpendicular to the central axis of the electron gun.

9. The X-ray generating device according to any one of claims 2 to 8, wherein: The magnet includes a permanent magnet.

10. The X-ray generating device according to any one of claims 1 to 9, wherein: The deflector comprises an electromagnet, and The adjustment unit adjusts the magnetic field generated by the electromagnet according to the acceleration voltage or the amount of change in the acceleration voltage.

11. An X-ray imaging device, comprising: An X-ray generating device as claimed in any one of claims 1 to 10; as well as An X-ray detector is configured to detect the X-rays emitted from the X-ray generation device.

12. A method for adjusting an X-ray generating device, the X-ray generating device comprising: An X-ray generating tube including an electron gun and a target configured to generate X-rays upon receiving an electron beam emitted from the electron gun; a deflector configured to deflect the electron beam; and a driving circuit configured to apply an accelerating voltage between a cathode of the electron gun and the target, The adjustment method of the X-ray generating device includes the following steps: adjusting the deflection of the electron beam caused by the deflector according to the acceleration voltage or the change in the acceleration voltage to reduce the change in the incident position of the electron beam on the target caused by the change in the acceleration voltage.

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