X-ray generating apparatus, x-ray imaging apparatus, and adjustment method for x-ray generating apparatus

Abstract

An X-ray generating apparatus includes an X-ray generating tube including an electron gun, and including 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 a cathode of the electron gun and the target; and an adjustment section for adjusting the deflection of the electron beam by the deflector in accordance with the acceleration voltage or a change amount of the acceleration voltage, to reduce a change in an incident position of the electron beam on the target due to a change in the acceleration voltage.

Description

Technical Field

[0001] This invention relates to an X-ray generating apparatus, an X-ray imaging apparatus, and a method for adjusting the X-ray generating apparatus. Background Technology

[0002] In a transmission-type X-ray tube, an electron beam irradiates a target, thereby emitting X-rays from the target. The electron beam generated at the cathode is accelerated by an accelerating voltage and irradiates the target. When this accelerating voltage is changed, the energy of the electron beam impacting the target changes. Patent Document 1 describes a transmission-type X-ray tube device comprising: an X-ray transmission window; a metal thin film forming an X-ray target disposed on the vacuum side of the X-ray transmission window; an electron gun that generates an electron beam; and deflection electrodes that deflect the electron beam. This metal thin film has a gradually varying thickness. In this X-ray tube device, the electron beam is irradiated at a point where the thickness of the metal thin film coincides with the depth to which the electrons penetrate. This operation is achieved by changing the deflection voltage applied to the deflection electrodes according to the accelerating voltage of the electron beam generated from the electron gun.

[0003] In an X-ray imaging apparatus that integrates an X-ray generating device, the accelerating voltage can be changed to alter the energy or energy distribution of the X-rays generated by the X-ray generating device. However, if the incident position of the electron beam on the target changes according to the change in accelerating voltage, the X-ray generation position, i.e., the focal position of the X-ray imaging apparatus, changes accordingly. Therefore, each time the accelerating voltage is changed, the position of the X-ray detector (used to detect the X-rays emitted from the X-ray generating device) needs to be adjusted.

[0004] Previous technical documents

[0005] [Patent Literature]

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

[0007] This invention provides a technique that helps reduce changes in the X-ray generation location caused by variations in accelerating voltage.

[0008] A first aspect of the present invention relates to an X-ray generating apparatus, the X-ray generating apparatus comprising: an X-ray generating tube including an electron gun and a target including an electron gun 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 the 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 according to the accelerating voltage or the amount of change of the accelerating voltage, so as to reduce the change in the incident position of the electron beam on the target caused by the change of the accelerating voltage.

[0009] A second aspect of the present invention relates to an X-ray imaging apparatus 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] A third aspect of the present invention relates to a method for adjusting an X-ray generating apparatus, the X-ray generating apparatus 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 drive circuit configured to apply an accelerating voltage between the cathode of the electron gun and the target; the adjustment method comprising the step of: adjusting the deflection of the electron beam caused by the deflector according to the accelerating voltage or the amount of change of the accelerating voltage, so as to reduce the change in the incident position of the electron beam on the target caused by the change of the accelerating voltage. Attached Figure Description

[0011] Figure 1 The diagram is shown schematically, illustrating the cross-sectional configuration near the center of an X-ray generating tube according to one embodiment.

[0012] Figure 2 This diagram is a schematic representation of how an electron beam emitted from an electron gun strikes a target.

[0013] Figure 3 This is a diagram illustrating a first configuration example of an X-ray generating apparatus.

[0014] Figure 4 The figures are for illustrating the first to fourth configuration examples of the X-ray generating apparatus.

[0015] Figure 5 This is a diagram illustrating a first configuration example of an X-ray generating apparatus.

[0016] Figure 6 The figures are for illustrating the first to fourth configuration examples of the X-ray generating apparatus.

[0017] Figure 7 This is a diagram illustrating a first configuration example of an X-ray generating apparatus.

[0018] Figure 8 The figures are for illustrating the first to fourth configuration examples of the X-ray generating apparatus.

[0019] Figure 9 This is a diagram illustrating a second configuration example of an X-ray generating apparatus.

[0020] Figure 10 This is a diagram illustrating a second configuration example of an X-ray generating apparatus.

[0021] Figure 11 This is a diagram illustrating a second configuration example of an X-ray generating apparatus.

[0022] Figure 12 This is a diagram illustrating a third configuration example of an X-ray generating apparatus.

[0023] Figure 13 This is a diagram illustrating a third configuration example of an X-ray generating apparatus.

[0024] Figure 14 This is a diagram illustrating a third configuration example of an X-ray generating apparatus.

[0025] Figure 15 This is a diagram illustrating the fourth configuration example of an X-ray generating apparatus.

[0026] Figure 16 This is a diagram illustrating the fourth configuration example of an X-ray generating apparatus.

[0027] Figure 17 This is a diagram illustrating the fifth configuration example of an X-ray generating apparatus.

[0028] Figure 18 This is a block diagram illustrating the configuration of an X-ray generating apparatus according to one embodiment.

[0029] Figure 19 A block diagram illustrating the configuration of an X-ray imaging apparatus according to one embodiment. Detailed Implementation

[0030] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the following embodiments are not intended to limit the scope of the invention. Although multiple features are described in the embodiments, it is not limited to the fact that all of these features are essential to the invention; moreover, these features can be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to denote the same or similar components, and repeated descriptions are omitted.

[0031] At Figure 1The diagram schematically illustrates the cross-sectional configuration near the center of an X-ray generating tube XG according to one embodiment. The X-ray generating apparatus 1 can be configured as a transmission-type X-ray generating apparatus. The X-ray generating apparatus 1 includes an X-ray generating tube XG. The X-ray generating tube XG may include an electron gun EG and a target 22 that receives an electron beam EB or electrons emitted from the electron gun EG to generate X-rays. For example, the X-ray generating tube XG may 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 blocking member 30 that closes the other of the two open ends of the insulating tube 10. The anode 20 may include: the 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 may, for example, be maintained at a ground potential. The blocking member 30 may be configured to hold the electron gun EG. The insulating tube 10, the anode 20, and the sealing member 30 can constitute a container that defines a sealed space. This sealed space can be maintained as a vacuum or a high vacuum.

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

[0033] X-ray generating apparatus 1 may include a cathode potential supply unit 41 that supplies cathode potential to the cathode CT. The cathode potential supply unit 41 can also be understood as a driving circuit that supplies an accelerating voltage between the anode 20, which can be maintained at a ground potential, and the cathode CT. X-ray generating apparatus 1 may include a lead-out potential supply unit 42 that supplies lead-out potential to the lead-out electrode EE. The lead-out potential supply unit 42 can also be understood as a component that supplies lead-out potential between the cathode CT and the lead-out electrode EE. X-ray generating apparatus 1 may include a convergence potential supply unit 43 that supplies convergence potential to the converging electrode CE. The convergence potential supply unit 43 can be understood as a component that supplies convergence voltage between the cathode CT and the converging electrode CE.

[0034] The X-ray generating apparatus 1 may further include a deflector 50 for deflecting the electron beam EB emitted from the electron gun EG. The deflector 50 may be disposed outside the X-ray generating tube XG. For example, the deflector 50 may be disposed such that an imaginary plane VP3 is located between imaginary planes VP1 and VP2, which transversely cuts the deflector 50. Imaginary plane VP1 includes the electron beam incident surface of the target 22 (the surface facing the electron gun EG), and imaginary plane VP2 includes the top surface of the electron gun EG (the surface facing the target 22). The imaginary planes VP1, VP2, and VP3 may be defined as planes perpendicularly intersecting 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 accelerating voltage.

[0035] The deflector 50 can be constructed using a permanent magnet, an electromagnet, or both. In one example, the deflector 50 may include a first magnet and a second magnet. The first magnetic pole (e.g., the S pole) of the first magnet and the second magnetic pole (e.g., the N pole) of the second magnet may be configured to face each other across the insulating tube 10 or the X-ray generating tube XG. Alternatively, the deflector 50 may be constructed using a single magnet, with its magnetic poles arranged radially towards the insulating tube 10 or the X-ray generating tube XG.

[0036] Electrode 23 is electrically connected to target 22, providing a potential to target 22. Target 22 generates X-rays by being struck by electrons from electron gun EG. The X-rays generated by target 22 pass through target holding plate 21 and are emitted towards the outside of X-ray generating tube XG. Anode 20 can be maintained at ground potential, for example, but can also be maintained at other potentials. Target 22 is constructed of a metallic material. Target 22 is preferably constructed of a material with a high melting point, such as tungsten, tantalum, or molybdenum. These materials are advantageous for improving the efficiency of X-ray generation. Target holding plate 21 can be constructed of a material through which X-rays can easily pass, such as beryllium or diamond.

[0037] X-ray generating apparatus 1 may include an adjustment unit 60 for adjusting the deflection of the electron beam EB caused by the deflector 50 according to the accelerating voltage or the amount of change in the accelerating voltage, thereby reducing the change in the incident position of the electron beam EB relative to the target 22 caused by the change in the accelerating voltage. In this case, the accelerating voltage, as described above, is the voltage supplied between the anode 20 and the cathode CT through the cathode potential supply unit 41. Without the adjustment unit 60, when the accelerating voltage changes, the amount by which the electron beam EB emitted from the electron gun EG is deflected by the deflector 50 changes, and thus the incident position of the electron beam EB relative to the target 22 may change. When the incident position of the electron beam EB relative to the target 22 changes due to the change in the accelerating voltage, the X-ray generation position changes in the X-ray imaging apparatus integrating the X-ray generating apparatus 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 apparatus (e.g., repositioning of the X-ray detector relative to the X-ray generating apparatus). Therefore, the X-ray generating apparatus 1 of this embodiment includes an adjustment unit 60, which is used to reduce the change in the incident position of the electron beam on the target 22 due to the change in the accelerating voltage. The incident position of the electron beam on the target 22 is a position on a plane (imaginary 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. This adjustment mechanism is a mechanical 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 (e.g., screw, spring) for fixing the deflector 50. The adjustment unit 60 can control the position of the magnet according to the accelerating voltage or the amount of change in the accelerating voltage, thereby reducing the change in the incident position of the electron beam EB on the target 22 caused by the change in the accelerating voltage. Controlling the position of the magnet using 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, controlling the position of the magnet using the adjustment unit 60 may include controlling the distance between the magnet and a line containing the central axis of the electron gun EG. Alternatively, controlling the position of the magnet in the adjustment unit 60 can include controlling the position of the magnet in a direction parallel to the central axis AX of the electron gun EG, and controlling the distance between the magnet and the line containing the central axis of the electron gun EG. Alternatively, the adjustment unit 60 can also control the rotation angle of the magnet according to the accelerating voltage or the amount of change in the accelerating voltage, thereby reducing the change in the incident position of the electron beam EB on the target 22 caused by the change in the accelerating voltage. Adjusting the rotation angle of the magnet in the adjustment unit 60 can include adjusting the rotation angle of the magnet about an axis perpendicular to the central axis AX of the electron gun EG. If the deflector 50 includes an electromagnet, the adjustment unit 60 can also be configured to adjust the magnetic field (e.g., the strength of the magnetic field) generated by the electromagnet according to the accelerating voltage or the amount of change in the accelerating voltage.

[0039] At Figure 2 The diagram schematically illustrates how the electron beam EB emitted from the electron gun EG impacts the target 22. Figure 2 The diagram shows the electron gun EG and target 22 close to each other, but the electron gun EG and target 22 can be configured to be further separated. The electron beam EB emitted from the electron gun EG is deflected by the magnetic field generated by the deflector 50 before incident on or impacting the target 22. The amount of deflection of the electron beam EB, in other words, the incident position of the electron beam EB on the target 22, can depend on the magnetic field and accelerating voltage generated by the deflector 50 and acting on the electron beam EB.

[0040] When the magnetic field (in intensity and direction) generated by the deflector 50 and acting on the electron beam EB is fixed, the incident position of the electron beam EB on the target 22 changes according to the change in accelerating voltage. Conversely, when the accelerating voltage is fixed, the incident position of the electron beam EB on the target 22 changes according to the change in at least one of the magnetic field (in intensity and direction) generated by the deflector 50 and acting on the electron beam EB. The adjustment unit 60 adjusts the magnetic field acting on the electron beam EB by the deflector 50 according to the accelerating voltage or the amount of change in the accelerating voltage. This adjusts 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 accelerating voltage.

[0041] At Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 This illustrates a first configuration example of the X-ray generating apparatus 1. Figure 3 , Figure 4 The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a first voltage V1, and the electron beam EB of the adjustment unit 60 is adjusted to a first state. The deflector 50 may be, for example, a pair of magnets arranged facing each other, clamping a central axis AX. Each magnet may be a permanent magnet, an electromagnet, or a combination of both. The adjustment unit 60 may include an adjustment mechanism for adjusting the position of the magnets serving as the deflector 50. This adjustment mechanism may include an actuator (e.g., a motor) 63 for driving the deflector 50. The adjustment unit 60, as the adjustment mechanism, may include a connector (holder) 61 for holding the deflector 50. In this case, the actuator 63 may be configured to drive the deflector 50 by driving the connector 61. The adjustment mechanism may also include a guide unit 62 for guiding the deflector 50 or the connector 61. The adjustment unit 60 is operable, or can be controlled, to adjust the position of the magnet of the deflector 50 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 the direction parallel to the central axis AX of the electron gun EG.

[0042] In the example shown Figure 3 , Figure 4 Under these conditions, the electron beam EB emitted from the electron gun EG is incident at position P1 of target 22. Figure 5 , Figure 6An X-ray generating apparatus 1 is schematically shown, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB of the adjustment unit 60 is adjusted to a first state. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. Furthermore, the accelerating voltage can be determined as the value of subtracting the potential of the cathode CT from the potential of the anode 20, i.e., it can be determined to be a positive value, or it can be determined as the value of subtracting the potential of the anode 20 from the potential of the cathode CT, i.e., it can be determined to be a negative value. (The diagram shows...) Figure 5 , Figure 6 In this state, the electron beam EB emitted from the electron gun EG is incident on the target 22 at position 2, P2. Position 2, P2, is closer to the straight line containing the central axis AX of the electron gun EG than position 1, P1. That is, the distance between position 2, P2, and the straight line containing the central axis AX is smaller than the distance between position 1, P1, and the straight line containing the central axis AX.

[0043] At Figure 7 , Figure 8 The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB is adjusted to a second state by the adjustment unit 60. The second state of the electron beam EB adjustment by the adjustment unit 60 preferably refers to the state where the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB relative to the target 22 is a first position P1. The second state of the adjustment unit 60 refers to the state where the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the accelerating voltage Va (=V2) or the amount of change in the accelerating voltage (=V1-V2) to reduce the change in the incident position of the electron beam EB relative to the target 22 (i.e., from the first position P1 to the second position P2) caused by the change of the accelerating voltage Va from the first voltage V1 to the second voltage V2.

[0044] The adjustment of the electron beam EB deflection using the adjustment unit 60 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 accelerating voltage Va. The target region preferably has a diameter that is three times or less the diameter of the electron beam EB on the target 22. By setting the target region in this way and adjusting it using the adjustment unit 60, it is unnecessary to perform the operation of positioning the X-ray detector in the X-ray generating apparatus according to the accelerating voltage.

[0045] In the first configuration example, when the accelerating voltage Va is changed in the direction of increasing the absolute value of the accelerating voltage Va, the adjustment unit 60 adjusts the position of the deflector 50 in a direction parallel to the line including the central axis AX, moving the deflector 50 away from the target 22. On the other hand, in the first configuration example, when the accelerating voltage Va is changed in the direction of decreasing the absolute value of the accelerating voltage Va, the adjustment unit 60 adjusts the position of the deflector 50 in a direction parallel to the line including the central axis AX, moving the deflector 50 closer to the target 22.

[0046] The position of the deflector 50 can be adjusted according to the accelerating voltage Va or the change in accelerating voltage. For example, the relationship between the magnitude of the accelerating voltage Va or the change in accelerating voltage and the appropriate position of the deflector 50 for directing the electron beam EB to the target region of the target 22 can be predetermined through experiments or calculations, and the adjustment can be performed based on this relationship. Alternatively, the adjustment of the position of the deflector 50 according to the accelerating voltage Va or the change in accelerating voltage can be performed by adjusting the position of the deflector 50 by the adjustment unit 60 while monitoring the incident position of the electron beam EB on the target 22 using an X-ray detector or the like, so that the electron beam EB will be incident on the target region of the target 22.

[0047] At Figure 9 , Figure 10 , Figure 11 , Figure 4 , Figure 6 , Figure 8 This illustrates a second configuration example of the X-ray generating apparatus 1. Figure 9 , Figure 4The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a first voltage V1, and the electron beam EB of the adjustment unit 60 is adjusted to a first state. The deflector 50 may be, for example, a pair of magnets arranged facing each other, clamping a central axis AX. Each magnet may be a permanent magnet, an electromagnet, or a combination of both. The adjustment unit 60 may include an adjustment mechanism for adjusting the position of the magnets serving as the deflector 50. This adjustment mechanism may include an actuator (e.g., a motor) 66 for driving the deflector 50. The adjustment mechanism may also include a connector (holder) 64 for holding the deflector 50. In this case, the actuator 66 may be configured to drive the deflector 50 by driving the connector 64. The adjustment mechanism may also include a guide unit 65 for guiding the deflector 50 or the connector 64. The adjustment unit 60 is operable, or can be controlled, to adjust the position of the magnet of the deflector 50 according to the acceleration voltage or the amount of change in the acceleration voltage. In the second embodiment, the control of the position of the magnet by the adjustment unit 60 includes adjusting the position of the magnet in a direction parallel to the distance between the magnet and the line containing the central axis AX of the electron gun EG. The second embodiment can also be combined with the first embodiment. That is, the control of the position of the magnet by the adjustment unit 60 can include adjusting the position of the magnet in a direction parallel to the central axis AX of the electron gun EG, and can also include adjusting the distance between the magnet and the line containing the central axis AX of the electron gun EG.

[0048] In the example shown Figure 9 , Figure 4 Under these conditions, the electron beam EB emitted from the electron gun EG is incident at position P1 of target 22. Figure 10 , Figure 6 The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB of the adjustment unit 60 is adjusted to a first state. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. Figure 10 , Figure 6 In this state, the electron beam EB emitted from the electron gun EG is incident on the target 22 at position 2, P2. Position 2, P2, is closer to the straight line containing the central axis AX of the electron gun EG than position 1, P1. That is, the distance between position 2, P2, and the straight line containing the central axis AX is smaller than the distance between position 1, P1, and the straight line containing the central axis AX.

[0049] At Figure 11 , Figure 8The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB is adjusted to a second state by the adjustment unit 60. The second state of the electron beam EB adjustment by the adjustment unit 60 preferably refers to the state where the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB relative to the target 22 is a first position P1. The second state of the adjustment unit 60 refers to the state where the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the accelerating voltage Va (=V2) or the amount of change in the accelerating voltage (=V1-V2) to reduce the change in the incident position of the electron beam EB relative to the target 22 (i.e., from the first position P1 to the second position P2) caused by the change of the accelerating voltage Va from the first voltage V1 to the second voltage V2.

[0050] The adjustment of the deflection of the electron beam EB using 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 accelerating voltage Va. The target region is preferably, for example, having a diameter that is three times or less the diameter of the electron beam EB on the target 22.

[0051] In the second configuration example, when the accelerating voltage Va is changed in the direction of increasing absolute value of accelerating voltage Va, the adjustment unit 60 adjusts the position of deflector 50 so that deflector 50 is close to the straight line containing the central axis AX. On the other hand, in the second configuration example, when the accelerating voltage Va is changed in the direction of decreasing absolute value of accelerating voltage Va, the adjustment unit 60 adjusts the position of deflector 50 so that deflector 50 is away from the straight line containing the central axis AX.

[0052] The position of the deflector 50 is adjusted according to the accelerating voltage Va or the change in accelerating voltage. For example, the relationship between the magnitude of the accelerating voltage Va or the change in accelerating voltage and the appropriate position of the deflector 50 for directing the electron beam EB to the target region of the target 22 can be predetermined through experiments or calculations, and the adjustment is performed based on this relationship. Alternatively, the position of the deflector 50 can be adjusted according to the accelerating voltage Va or the change in accelerating voltage by adjusting the position of the deflector 50 by the adjustment unit 60 while monitoring the incident position of the electron beam EB on the target 22 using an X-ray detector or the like, so that the electron beam EB will be incident on the target region of the target 22.

[0053] At Figure 12 , Figure 13 , Figure 14 , Figure 4 , Figure 6 , Figure 8 This illustrates a third configuration example of the X-ray generating apparatus 1. Figure 12 , Figure 4The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a first voltage V1, and the electron beam EB of the adjustment unit 60 is adjusted to a first state. The deflector 50 may be, for example, a pair of magnets arranged facing each other, clamping a central axis AX. Each magnet may be a permanent magnet, an electromagnet, or a combination of both. The adjustment unit 60 may include an adjustment mechanism for adjusting the position of the magnets serving as the deflector 50. This adjustment mechanism may include an actuator (e.g., a motor) 69 for driving the deflector 50. The adjustment mechanism may also include a connector (holder) 67 for holding the deflector 50. In this case, the actuator 69 may be configured to drive the deflector 50 by driving the connector 67. The adjustment mechanism may also include a guide unit 68 for guiding the deflector 50 or the connector 67. The adjustment unit 60 is operable, or can be controlled, to adjust the rotation angle of the magnet of the deflector 50 according to the accelerating voltage or the amount of change in the accelerating voltage. Controlling the rotation angle of the magnet using the adjustment unit 60 can include adjusting the rotation angle of the magnet about an 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 example shown Figure 12 , Figure 4 Under these conditions, the electron beam EB emitted from the electron gun EG is incident at position P1 of target 22. Figure 13 , Figure 6 The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB of the adjustment unit 60 is adjusted to a first state. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. Figure 13 , Figure 6 In this state, the electron beam EB emitted from the electron gun EG is incident on the target 22 at position 2, P2. Position 2, P2, is closer to the straight line containing the central axis AX of the electron gun EG than position 1, P1. That is, the distance between position 2, P2, and the straight line containing the central axis AX is smaller than the distance between position 1, P1, and the straight line containing the central axis AX.

[0055] At Figure 14 , Figure 8The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB is adjusted to a second state by the adjustment unit 60. The second state of the electron beam EB adjustment by the adjustment unit 60 preferably refers to the state where the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB relative to the target 22 is a first position P1. The second state of the adjustment unit 60 refers to the state where the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the accelerating voltage Va (=V2) or the amount of change in the accelerating voltage (=V1-V2) to reduce the change in the incident position of the electron beam EB relative to the target 22 (i.e., from the first position P1 to the second position P2) caused by the change of the accelerating voltage Va from the first voltage V1 to the second voltage V2.

[0056] The adjustment of the deflection of the electron beam EB using 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 accelerating voltage Va. The target region is preferably, for example, having a diameter that is three times or less the diameter of the electron beam EB on the target 22.

[0057] In the third configuration example, when the accelerating voltage Va is changed in the direction of increasing the absolute value of the accelerating 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 accelerating voltage Va is changed in the direction of decreasing the absolute value of the accelerating 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 rotation angle of the deflector 50, adjusted according to the accelerating voltage Va or the change in accelerating voltage, can be determined in advance, for example, by experimentally or by calculation, the relationship between the magnitude of the accelerating voltage Va or the change in accelerating voltage and the appropriate rotation angle of the deflector 50 for directing the electron beam EB to the target region of the target 22, and the adjustment can be performed based on this relationship. Alternatively, the adjustment of the rotation angle of the deflector 50, according to the accelerating voltage Va or the change in accelerating voltage, can be performed by adjusting the rotation angle of the deflector 50 by the adjustment unit 60 while monitoring the incident position of the electron beam EB on the target 22 using an X-ray detector or the like, so that the electron beam EB will be incident on the target region of the target 22.

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

[0060] In the example shown Figure 15 , Figure 4 Under these conditions, the electron beam EB emitted from the electron gun EG is incident at position P1 of target 22. Figure 16 , Figure 6 The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB of the adjustment unit 60 is adjusted to a first state. In this case, the absolute value of the second voltage V2 is greater than the absolute value of the first voltage V1. Figure 16 , Figure 6 In this state, the electron beam EB emitted from the electron gun EG is incident on the target 22 at position 2, P2. Position 2, P2, is closer to the straight line containing the central axis AX of the electron gun EG than position 1, P1. That is, the distance between position 2, P2, and the straight line containing the central axis AX is smaller than the distance between position 1, P1, and the straight line containing the central axis AX.

[0061] At Figure 17 , Figure 8 The diagram schematically illustrates an X-ray generating apparatus 1, wherein the accelerating voltage Va is a second voltage V2, and the electron beam EB is adjusted to a second state by the adjustment unit 60. The second state of the electron beam EB adjustment by the adjustment unit 60 preferably refers to the state where the electron beam EB is adjusted by the adjustment unit 60 so that the incident position of the electron beam EB relative to the target 22 is a first position P1. The second state of the adjustment unit 60 refers to the state where the deflection of the electron beam EB caused by the deflector 50 is adjusted by the adjustment unit 60 according to the accelerating voltage Va (=V2) or the amount of change in the accelerating voltage (=V1-V2) to reduce the change in the incident position of the electron beam EB relative to the target 22 (i.e., from the first position P1 to the second position P2) caused by the change of the accelerating voltage Va from the first voltage V1 to the second voltage V2.

[0062] The adjustment of the deflection of the electron beam EB using 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 accelerating voltage Va. The target region is preferably, for example, having a diameter that is three times or less the diameter of the electron beam EB on the target 22.

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

[0064] The position of the deflector 50 is adjusted according to the accelerating voltage Va or the change in accelerating voltage. For example, the relationship between the magnitude of the accelerating voltage Va or the change in accelerating voltage and the magnitude of the current supplied to the deflector 50 to ensure that the electron beam EB is incident on the target region of the target 22 can be predetermined through experiments or calculations, and the adjustment is performed based on this relationship. Alternatively, the position of the deflector 50 is adjusted according to the accelerating voltage Va or the change in accelerating voltage by monitoring the incident position of the electron beam EB on the target 22 using an X-ray detector or the like, while adjusting the current supplied from the adjustment unit 60 to the deflector 50 so that the electron beam EB will be incident on the target region of the target 22.

[0065] At Figure 18 The diagram illustrates the configuration of an X-ray generating apparatus 1 according to one embodiment. In addition to the X-ray generating tube XG described above, the X-ray generating apparatus 1 may include a boost circuit 110 and a drive circuit 120. The boost circuit 110 generates a boosted voltage obtained by boosting an externally supplied voltage and supplies this boosted voltage to the drive circuit 120. The drive circuit 120 drives the X-ray generating tube XG based on the boosted voltage supplied from the boost circuit 110. The drive circuit 120 may include the aforementioned cathode potential supply unit 41, lead-out potential supply unit 42, and convergence potential supply unit 43.

[0066] At Figure 19The diagram illustrates the configuration of an X-ray imaging apparatus 200 according to one embodiment. The X-ray imaging apparatus 200 may include an X-ray generating apparatus 1 and an X-ray detection apparatus 240 that may detect X-rays (XR) emitted from the X-ray generating apparatus 1 that have passed through an object 230. The X-ray detection apparatus 240 may further include a control device 210 and a display device 220. The X-ray detection apparatus 240 may include an X-ray detector 242 and a signal processing unit 244. The control device 210 controls the X-ray generating apparatus 1 and the X-ray detection apparatus 240. The X-ray detector 242 detects or images the X-rays (XR) emitted from the X-ray generating apparatus 1 that have passed through the object 230. The signal processing unit 244 processes the signal output from the X-ray detector 242 and supplies the processed signal to the control device 210. The control device 210 displays the 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 caused by the change in the acceleration voltage, or the amount of change in the acceleration voltage, according to the acceleration voltage or the amount of change in the acceleration voltage.

[0067] Symbol Explanation

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

Claims

1. An X-ray generating device, comprising: An X-ray generating tube 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 driving circuit configured to apply an accelerating voltage between the 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, based on the accelerating voltage or the amount of change in the accelerating voltage, so as to reduce the change in the incident position of the electron beam on the target caused by the change in the accelerating voltage. The deflector includes a permanent magnet. The adjustment unit includes an adjustment mechanism configured to adjust the position of the permanent magnet according to the accelerating voltage or the amount of change in the accelerating voltage, and The adjustment of the position of the permanent magnet using the adjustment mechanism includes the adjustment of the position of the permanent magnet in a direction parallel to the central axis of the electron gun.

2. The X-ray generating apparatus as claimed in claim 1, wherein, The permanent magnet includes a first magnet and a second magnet arranged facing each other across the X-ray generating tube, and The amount of deflection of the electron beam caused by the deflector is changed by adjusting the position of the permanent magnet using the adjustment mechanism.

3. The X-ray generating apparatus as described in claim 2, wherein, The first magnet and the second magnet are arranged such that the first magnetic pole of the first magnet and the second magnetic pole of the second magnet face each other across the X-ray generating tube, and the first magnetic pole and the second magnetic pole are opposite to each other. The amount of deflection of the electron beam caused by the deflector is changed by adjusting the position of the permanent magnet using the adjustment mechanism.

4. The X-ray generating apparatus as claimed in claim 1, wherein, The adjustment mechanism includes an actuator configured to drive the deflector.

5. The X-ray generating apparatus as described in claim 1, wherein, The adjustment mechanism includes a guide portion configured to guide the deflector.

6. The X-ray generating apparatus as claimed in claim 4, wherein, The adjustment mechanism includes a fixing mechanism configured to fix the deflector.

7. The X-ray generating apparatus as claimed in claim 1, wherein, The adjustment mechanism includes a mechanism configured to adjust the rotation angle of the permanent magnet according to the accelerating voltage or the amount of change in the accelerating voltage, so as to reduce the change in the incident position of the electron beam on the target caused by the change in the accelerating voltage.

8. The X-ray generating apparatus as claimed in claim 7, wherein, The adjustment of the rotation angle of the permanent magnet using the adjustment mechanism includes adjusting the rotation angle of the permanent magnet about an axis perpendicular to the central axis of the electron gun.

9. The X-ray generating apparatus as claimed in claim 1, wherein, The deflector also includes an electromagnet.

10. The X-ray generating apparatus as claimed in claim 1, wherein, The incident position is within a region, the diameter of which is less than three times the diameter of the electron beam at the target.

11. An X-ray imaging device, comprising: The X-ray generating apparatus as described in claim 1; as well as An X-ray detector configured to detect X-rays emitted from the X-ray generating device.

12. A method for adjusting an X-ray generating device, the X-ray generating device comprising: An X-ray generating tube 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; And a driving circuit configured to apply an accelerating voltage between the cathode of the electron gun and the target. The adjustment method for the X-ray generating device includes the following steps: adjusting the deflection of the electron beam caused by the deflector according to the accelerating voltage or the amount of change in the accelerating voltage, so as to reduce the change in the incident position of the electron beam on the target caused by the change in the accelerating voltage. The deflector includes a permanent magnet. The step includes adjusting the position of the permanent magnet according to the accelerating voltage or the amount of change in the accelerating voltage, and Adjustment of the position of the permanent magnet contained in a direction parallel to the central axis of the electron gun.

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