X-ray generating device and X-ray generating method

Abstract

The X-ray generating device of the present invention comprises: an electron gun that emits an electron beam having a circular cross-sectional shape; a magnetic focusing lens that is arranged at a rear portion relative to the electron gun and focuses the electron beam while rotating the electron beam around an axis along a first direction; a magnetic quadrupole lens that is arranged at a rear portion relative to the magnetic focusing lens and deforms the cross-sectional shape of the electron beam into an elliptical shape having a major axis along a second direction perpendicular to the first direction and a minor axis along a third direction perpendicular to the first and second directions; and a target that is arranged at a rear portion relative to the magnetic quadrupole lens and emits X-rays in response to the incidence of the electron beam.

Description

Technical Field

[0001] One aspect of the present disclosure relates to an X-ray generating device and an X-ray generating method. Background Art

[0002] X-ray devices are known that generate X-rays by allowing an electron beam emitted from a cathode to enter a target. For example, Patent Document 1 describes a reflective target having an electron incident surface tilted relative to the direction of travel of the electron beam. Furthermore, Patent Document 2 describes adjusting the cross-sectional shape of the electron beam.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-164819

[0006] Patent Document 2: Japanese Patent No. 6527239 Summary of the Invention

[0007] Problems that the invention aims to solve

[0008] In certain X-ray devices, the focal point of the extracted X-rays (effective focal point) is not the shape of the electron beam incident on the target (i.e., the shape of the electron beam as viewed from the incident direction), but rather the shape of the projection as viewed from the extraction direction (the direction in which the X-rays are emitted). Furthermore, in X-ray inspections, etc., to obtain images with consistent resolution in both the vertical and horizontal directions, it is desirable to have the effective focal point have consistent vertical and horizontal dimensions (i.e., a roughly circular shape). One method for achieving a roughly circular effective focal point is to have the beam cross-section of the electron beam incident on the target be elliptical.

[0009] Unexpected changes in the cross-sectional shape of the electron beam can be caused, for example, by degradation of one or more components of the X-ray device. Furthermore, if the cross-sectional shape of the electron beam is determined by the shape of the gate electrode opening, there is a concern that the shape formed by the X-ray device, such as the aspect ratio of the major and minor axes of the elliptical shape, cannot be changed or corrected.

[0010] Furthermore, in a specific type of X-ray apparatus that uses two quadrupole cores to adjust the cross-sectional shape of an electron beam, it is sometimes difficult to simultaneously adjust both the aspect ratio of the cross-sectional shape of the electron beam and the size of the electron beam by combining the two quadrupole cores.

[0011] This specification discloses an example of an X-ray generating device that can easily and flexibly adjust the aspect ratio and size of the cross-sectional shape of an electron beam.

[0012] Technical means to solve problems

[0013] An exemplary X-ray generator includes an electron gun that emits an electron beam having a circular cross-sectional shape; and a magnetic focusing lens disposed after the electron gun and focusing the electron beam while rotating it about an axis (rotation axis) along a first direction. Alternatively, the X-ray generator may include a magnetic quadrupole lens disposed after the magnetic focusing lens and deforming the circular cross-sectional shape of the electron beam into an elliptical cross-sectional shape having a major axis along a second direction perpendicular to the first direction and a minor axis along a third direction perpendicular to both the first and second directions. Furthermore, the X-ray generator may include a target disposed after the magnetic quadrupole lens and emitting X-rays in response to the incident electron beam.

[0014] In several embodiments, the size of the electron beam is adjusted by a magnetic focusing lens positioned behind the electron gun, and the cross-sectional shape of the electron beam is deformed into an elliptical shape by a magnetic quadrupole lens positioned behind the magnetic focusing lens. This allows the size and cross-sectional shape of the electron beam to be adjusted independently. Furthermore, the electron beam passing through the magnetic focusing lens rotates about an axis along a first direction. However, since the cross-sectional shape of the electron beam emitted by the electron gun is circular, the cross-sectional shape of the electron beam that reaches the magnetic quadrupole lens via the magnetic focusing lens remains constant (circular) regardless of the amount of rotation of the electron beam within the magnetic focusing lens. This allows the cross-sectional shape of the electron beam at the magnetic quadrupole lens to be consistently and reliably formed into an elliptical shape having a major axis along a second direction and a minor axis along a third direction. As a result, the aspect ratio and size of the electron beam's cross-sectional shape can be easily and flexibly adjusted.

[0015] The target may have an electron incident surface on which the electron beam is incident. The electron incident surface may be tilted relative to the first direction and the second direction. The ratio of the major axis to the minor axis of the electron beam after being deformed into an elliptical cross-sectional shape by the magnetic quadrupole lens, and the tilt angle of the electron incident surface relative to the first direction and the second direction, can determine the roughly circular focus shape of the X-ray observed from the direction of X-ray extraction. Thus, by adjusting the tilt angle of the electron incident surface of the target and the shaping conditions (aspect ratio) achieved by the magnetic quadrupole lens, the shape of the focus (effective focus) of the extracted X-ray can be set to a roughly circular shape. As a result, in X-ray inspection using X-rays generated by an X-ray generator, etc., an appropriate inspection image can be obtained.

[0016] The length of the magnetic focusing lens along the first direction can be longer than the length of the magnetic quadrupole lens along the first direction. For example, because the magnetic focusing lens generates a relatively large magnetic field and effectively focuses the electron beam to a small size, the number of turns of the magnetic focusing lens coil can be reliably ensured. This improves the reduction ratio. Furthermore, to reduce the size of the electron beam incident on the electron entrance surface of the target, the distance from the electron gun to the center of the lens formed by the magnetic focusing lens can be lengthened.

[0017] The inner diameter of the pole piece of the magnetic focusing lens can be larger than that of the magnetic quadrupole lens. For example, by making the inner diameter of the pole piece of the magnetic focusing lens relatively large, the spherical aberration of the lens formed by the magnetic focusing lens can be reduced. Furthermore, by making the inner diameter of the magnetic quadrupole lens relatively small, the number of turns of the coil of the magnetic quadrupole lens and the amount of current flowing through the coil can be reduced. As a result, the heat generated by the magnetic quadrupole lens can be suppressed.

[0018] The X-ray generating device may further include a cylindrical portion extending along the first direction to form an electron passage path for the electron beam. The magnetic focusing lens and the magnetic quadrupole lens may be directly or indirectly connected to the cylindrical portion. For example, since the magnetic focusing lens and the magnetic quadrupole lens can be arranged or installed using the cylindrical portion as a reference, the central axes of the magnetic focusing lens and the magnetic quadrupole lens can be precisely aligned on the same axis. As a result, deformation of the profile (cross-sectional shape) of the electron beam after passing through the magnetic focusing lens and the magnetic quadrupole lens can be suppressed.

[0019] The X-ray generator may further include a deflection coil for adjusting the direction of travel of the electron beam. For example, the deflection coil may adjust the angular offset between the exit axis of the electron beam emitted from the electron gun and the central axis of the magnetic focusing lens and the magnetic quadrupole lens. For example, the angular offset may occur when the exit axis intersects the central axis at a specific angle. Therefore, by using the deflection coil to change the direction of travel of the electron beam to a direction along the central axis, the angular offset can be eliminated.

[0020] The deflection yoke can be placed between the electron gun and the magnetic focusing lens. For example, it can prioritize the electron beam's direction of travel before it passes through the magnetic focusing lens and the magnetic quadrupole lens. As a result, the cross-sectional shape of the electron beam incident on the target can be reliably maintained at the desired elliptical shape.

[0021] [Effects of the Invention]

[0022] As described above, the exemplary X-ray generating apparatus disclosed in this specification can be configured to easily and flexibly adjust the aspect ratio and size of the cross-sectional shape of the electron beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of an exemplary X-ray generating device.

[0024] Figure 2 This is a schematic cross-sectional view showing a configuration example of a magnetic lens of an X-ray generator.

[0025] Figure 3 is a front view of an exemplary magnetic quadrupole lens.

[0026] Figure 4 Schematic diagram of the structure (doublet lens) of the embodiment and the comparative example including the magnetic focusing lens and the magnetic quadrupole lens.

[0027] Figure 5 This is a diagram showing an example of the relationship between the cross-sectional shape of an electron beam and the shape of an effective focal point of X-rays.

[0028] Figure 6 It is a diagram showing a first variation of the cylindrical tube.

[0029] Figure 7 It is a diagram showing a second variation of the cylindrical tube.

[0030] Figure 8 This is a schematic structural diagram of an X-ray generating device according to a modified example. DETAILED DESCRIPTION

[0031] In the following description, the same or corresponding elements are denoted by the same reference numerals with reference to the drawings, and redundant description is omitted.

[0032] like Figure 1 As shown, the exemplary X-ray generator 1 includes an electron gun 2, a rotating anode unit 3, a magnetic lens 4, an exhaust section 5, a housing 6 (first housing) defining an interior space S1 for accommodating the electron gun 2, and a housing 7 (second housing) defining an interior space S2 for accommodating the rotating anode unit 3. The housings 6 and 7 may be detachable from each other, integrally coupled to each other in a non-detachable manner, or integrally formed from the outset.

[0033] The electron gun 2 emits an electron beam EB. The electron gun 2 has a cathode C that emits the electron beam EB. The cathode C is a circular planar cathode that emits an electron beam EB having a circular cross-sectional shape. The so-called cross-sectional shape of the electron beam EB refers to the cross-sectional shape in the direction perpendicular to the X-axis direction (first direction) which is parallel to the direction of travel of the electron beam EB described later. That is, the cross-sectional shape of the electron beam EB is the shape within the YZ plane. In order to form an electron beam EB having a circular cross-sectional shape, for example, the electron emission surface of the cathode C itself may have a circular shape when observed from a position opposite to the electron emission surface of the cathode C (the electron emission surface of the cathode C is observed from the X-axis direction).

[0034] The rotating anode unit 3 includes a target 31, a rotating support 32, and a drive unit 33 that rotates the rotating support 32 about a rotation axis A. The target 31 is disposed along the periphery of the rotating support 32, which is formed in a flat truncated cone shape with the rotation axis A as its center axis. The rotation axis A is the central axis of the rotating support 32, and the side surfaces of the truncated cone-shaped rotating support 32 have surfaces inclined relative to the rotation axis A. Alternatively, the rotating support 32 may be formed in a ring shape with the rotation axis A as its center axis. The target 31 is made of, for example, heavy metals such as tungsten, silver, rhodium, molybdenum, and alloys thereof. The rotating support 32 is rotatable about the rotation axis A. The rotating support 32 is made of, for example, a metal such as copper or a copper alloy. The drive unit 33 includes a drive source such as a motor and rotates the rotating support 32 about the rotation axis A. As the rotating support 32 rotates, the target 31 receives the electron beam EB and generates X-rays XR. X-rays XR are emitted from the X-ray passage hole 7a formed in the frame 7 toward the outside of the frame 7. The X-ray passage hole 7a is sealed airtightly by a window member 8. The axial direction of the rotation axis A is parallel to the incident direction of the electron beam EB toward the target 31. However, the rotation axis A may be tilted so as to extend in a direction intersecting the incident direction relative to the incident direction of the electron beam EB toward the target 31. The target 31 may be a so-called reflective type that emits X-rays XR in a direction intersecting the direction of travel of the electron beam EB (the direction of incidence toward the target 31). In some embodiments, the emission direction of the X-rays XR is a direction orthogonal to the direction of travel of the electron beam EB. Therefore, the direction parallel to the direction of travel of the electron beam EB is set as the X-axis direction (first direction), the direction parallel to the emission direction of the X-rays XR from the target 31 is set as the Z-axis direction (second direction), and the direction orthogonal to the X-axis direction and the Z-axis direction is set as the Y-axis direction (third direction).

[0035] The magnetic lens 4 controls the electron beam EB. The magnetic lens 4 includes a deflection coil 41, a magnetic focusing lens 42, a magnetic quadrupole lens 43, and a frame 44. The frame 44 houses the deflection coil 41, the magnetic focusing lens 42, and the magnetic quadrupole lens 43. The deflection coil 41, the magnetic focusing lens 42, and the magnetic quadrupole lens 43 are arranged in sequence along the X-axis direction, from the electron gun 2 side to the target 31 side. An electron passage P is formed between the electron gun 2 and the target 31, through which the electron beam EB passes. Figure 2 As shown, the electron passage P can be formed by a cylindrical tube 9 (cylindrical portion). The cylindrical tube 9 is a non-magnetic metal member extending along the X-axis between the electron gun 2 and the target 31. The details of the additional exemplary structure of the cylindrical tube 9 will be described later.

[0036] The deflection coil 41, magnetic focusing lens 42, and magnetic quadrupole lens 43 are directly or indirectly connected to the cylindrical tube 9. For example, by assembling the deflection coil 41, magnetic focusing lens 42, and magnetic quadrupole lens 43 with reference to the cylindrical tube 9, their respective central axes are precisely aligned coaxially. Consequently, the central axes of the deflection coil 41, magnetic focusing lens 42, and magnetic quadrupole lens 43 coincide with the central axis of the cylindrical tube 9 (an axis parallel to the X-axis).

[0037] The deflection coil 41 is arranged between the electron gun 2 and the magnetic focusing lens 42. The deflection coil 41 is arranged so as to surround the electron passage path P. For example, the deflection coil 41 is indirectly connected to the cylindrical tube 9 via the cylindrical member 10. The cylindrical member 10 is a non-magnetic metal member extending coaxially with the cylindrical tube 9. The cylindrical member 10 is provided to cover the outer circumference of the cylindrical tube 9. The deflection coil 41 is positioned by the surface of the wall portion 44a on the target 31 side and the outer circumferential surface of the cylindrical member 10. The wall portion 44a is a part of the frame 44 arranged at a position opposite to the internal space S1 and is composed of a non-magnetic material. The deflection coil 41 adjusts the direction of travel of the electron beam EB emitted from the electron gun 2. The deflection coil 41 may include one (one group) of deflection coils or two (two groups) of deflection coils. In the former case, where the deflection coil 41 comprises a single deflection coil, the deflection coil 41 can be configured to correct for angular misalignment between the exit axis of the electron beam EB emitted from the electron gun 2 and the central axis (axis parallel to the X-axis) of the magnetic focusing lens 42 and the magnetic quadrupole lens 43. For example, angular misalignment can occur when the exit axis and the central axis intersect at a specific angle. Therefore, the angular misalignment can be eliminated by using the deflection coil 41 to change the direction of travel of the electron beam EB to a direction along the central axis. In the latter case, where the deflection coil 41 comprises two deflection coils, the deflection coil 41 can perform two-dimensional deflection. Therefore, not only can the angular misalignment be corrected, but also lateral misalignment between the exit axis and the central axis (for example, when the exit axis and the central axis are parallel in the X-axis direction and spaced apart in one or both of the Y-axis and Z-axis directions) can be appropriately corrected.

[0038] The magnetic focusing lens 42 is arranged at a rearward position relative to the electron gun 2 and the deflection coil 41. The magnetic focusing lens 42 focuses the electron beam EB while rotating it around an axis along the X-axis. For example, the electron beam EB passing through the magnetic focusing lens 42 is focused while rotating in a spiral pattern. The magnetic focusing lens 42 includes a coil 42a, a pole piece 42b, a yoke 42c, and a yoke 42d, arranged to surround the electron path P. The yoke 42c also functions as a wall 44b of the frame 44, which is provided to connect a portion of the outer side of the coil 42a to the cylindrical member 10. The yoke 42d is a cylindrical member provided to cover the outer circumference of the cylindrical member 10. For example, the coil 42a is indirectly connected to the cylindrical tube 9 via the cylindrical member 10 and the yoke 42d. The pole piece 42b includes the yoke 42c and the yoke 42d. The yoke 42c and the yoke 42d are ferromagnetic materials such as iron. Alternatively, pole piece 42b may include a notch (gap) between yoke 42c and yoke 42d, and portions of yoke 42c and yoke 42d located near the notch. The inner diameter D of pole piece 42b is equal to the inner diameter of the region adjacent to the gap between yoke 42c or yoke 42d. Therefore, magnetic focusing lens 42 may be configured so that the magnetic field of coil 42a leaks from pole piece 42b toward cylindrical tube 9.

[0039] The magnetic quadrupole lens 43 is arranged at a rear section relative to the magnetic focusing lens 42. The magnetic quadrupole lens 43 deforms the cross-sectional shape of the electron beam EB into an elliptical shape having a major diameter along the Z-axis direction and a minor diameter along the Y-axis direction. The magnetic quadrupole lens 43 is arranged so as to surround the electron passage path P. For example, the magnetic quadrupole lens 43 is indirectly connected to the cylindrical tube 9 via the wall portion 44c of the frame 44. The wall portion 44c is arranged to be connected to the wall portion 44b and to cover the outer circumference of the cylindrical tube 9. The wall portion 44c comprises a non-magnetic metal material.

[0040] like Figure 3As shown, the exemplary magnetic quadrupole lens 43 comprises an annular yoke 43a, four cylindrical yokes 43b disposed on the inner circumference of yoke 43a, and a yoke 43c disposed at the tip of each yoke 43b. A coil 43d is wound around the yoke 43b. Each yoke 43c has a roughly semicircular cross-section in the YZ plane. The inner diameter d of the magnetic quadrupole lens 43 is the diameter of the inscribed circle passing through the innermost end of each yoke 43c. The magnetic quadrupole lens 43 functions as a concave lens in the XZ plane (a plane perpendicular to the Y-axis direction) and as a convex lens in the XY plane (a plane perpendicular to the Z-axis direction). This function of the magnetic quadrupole lens 43 adjusts the aspect ratio between the diameter of the electron beam EB in the Z-axis direction (the major diameter X1) and the diameter in the Y-axis direction (the minor diameter X2) so that the length of the electron beam EB in the Z-axis direction is greater than its length in the Y-axis direction. Therefore, by adjusting the amount of current flowing through the coil 43d, the aspect ratio can be selectively adjusted. As an example, the aspect ratio of the major diameter X1 to the minor diameter X2 is adjusted to "10:1".

[0041] The exhaust section 5 includes a vacuum pump 5a (a first vacuum pump) and a vacuum pump 5b (a second vacuum pump). The frame 6 is provided with an exhaust flow path E1 (a first exhaust flow path) for vacuum exhausting the space within the frame 6 (i.e., the internal space S1 defined by the frame 6 and the frame 44 of the magnetic lens 4). The vacuum pump 5b is connected to the internal space S1 via the exhaust flow path E1. The frame 7 is provided with an exhaust flow path E2 (a second exhaust flow path) for vacuum exhausting the space within the frame 7 (i.e., the internal space S2 defined by the frame 7). The vacuum pump 5a is connected to the internal space S2 via the exhaust flow path E2. The vacuum pump 5b vacuum exhausts the internal space S1 via the exhaust flow path E1. The vacuum pump 5a vacuum exhausts the internal space S2 via the exhaust flow path E2. As a result, the internal space S1 and the internal space S2 are maintained in a vacuum state or a partial vacuum state, for example, by removing gas generated in the electron gun or the target. The internal pressure of the internal space S1 is preferably maintained at 10 -4 Partial vacuum below Pa, preferably maintained at 10 -5 The internal pressure of the internal space S2 is preferably maintained at 10 -6 Pa~10 -3 The partial vacuum between Pa. The internal space of the cylindrical tube 9 (the space within the electron passage P) is also vacuum-evacuated by the exhaust unit 5 via the internal space S1 or the internal space S2.

[0042] Furthermore, it may not be like this Figure 1 As shown in the embodiment, two exhaust pumps, namely vacuum pump 5a and vacuum pump 5b, are used. Figure 8As shown, a structure (X-ray generating device 1A) is adopted in which both the internal space S1 and the internal space S2 can be vacuum-exhausted by a single exhaust pump (here, vacuum pump 5b is used as an example). In some embodiments, the exhaust flow path E1 and the exhaust flow path E2 can be connected by a connecting path E3 located outside the frame 6 and the frame 7. In other examples, the connecting path E3 may also include a through hole, which is continuously provided from the wall of the frame 7 to the wall of the frame 6 in a manner that connects the exhaust flow path E1 and the exhaust flow path E2. Furthermore, either the vacuum pump 5a or the vacuum pump 5b can be used as the single exhaust pump. By using the vacuum pump 5b connected to the exhaust flow path E1 as the exhaust pump, more efficient vacuum exhaust can be achieved.

[0043] In some embodiments, a voltage is applied to the electron gun 2 while the internal spaces S1 and S2 and the electron passage P are evacuated. As a result, an electron beam EB with a circular cross-section is emitted from the electron gun 2. The electron beam EB is focused by the magnetic lens 4 onto the target 31, deformed into an elliptical cross-section, and incident on the rotating target 31. When the electron beam EB enters the target 31, X-rays XR are generated on the target 31. The X-rays XR, having a substantially circular effective focus, are emitted from the X-ray passage aperture 7a toward the exterior of the housing 7.

[0044] like Figure 2 As shown, the cylindrical tube 9 has a configuration in which its diameter changes stepwise along the X-axis. For example, the cylindrical tube 9 includes six cylindrical portions 91 to 96 arranged along the X-axis. Each cylindrical portion 91 to 96 has a constant diameter along the X-axis. The outer diameter of the cylindrical tube 9 does not necessarily change synchronously with its inner diameter. In other words, the outer diameter of the cylindrical tube 9 can be constant.

[0045] The cylindrical portion 91 (first cylindrical portion) includes a first end 9a of the cylindrical tube 9 on the electron gun 2 side. The cylindrical portion 91 extends from the first end 9a to a second end 91a, surrounded by the portion of the coil 42a on the electron gun 2 side of the boundary portion 9c. The first end 92a of the cylindrical portion 92 (second cylindrical portion) is connected to the second end 91a of the cylindrical portion 91 on the target 31 side. In some embodiments, the cylindrical portion 92 extends from the second end 91a of the cylindrical portion 91 to the second end 92b of the second cylindrical portion 92, which is located slightly closer to the target 31 side than the pole piece 42b. For example, the second end 92b of the second cylindrical portion 92 may be located between the pole piece 42b and the target 31 along the X-axis. Furthermore, the first end 93a of the cylindrical portion 93 (third cylindrical portion) is connected to the second end 92b of the cylindrical portion 92 on the target 31 side.

[0046] The cylindrical portion 93 extends from the second end 92b of the cylindrical portion 92 to the second end 93b of the cylindrical portion 93 surrounded by the magnetic quadrupole lens 43. The first end of the cylindrical portion 94 (the fourth cylindrical portion) is connected to the second end 93b of the cylindrical portion 93 on the target 31 side. The cylindrical portion 94 extends from the second end 93b of the cylindrical portion 93 to the frame 7 side of the wall portion 44c.

[0047] The cylindrical portion 95 (the fifth cylindrical portion) and the cylindrical portion 96 (the sixth cylindrical portion) pass through the interior of the wall portion 71 of the frame 7. The wall portion 71 is arranged at a position opposite to the target 31 and extends in a manner intersecting the X-axis direction. The cylindrical portion 95 is connected to the second end portion of the cylindrical portion 94 on the target 31 side. The cylindrical portion 95 extends from the end portion of the cylindrical portion 94 to the middle portion of the interior of the wall portion 71. The cylindrical portion 96 is connected to the end portion of the cylindrical portion 95 on the target 31 side at the middle portion of the interior of the wall portion 71. The cylindrical portion 96 extends from the end portion of the cylindrical portion 95 to the second end portion 9b of the cylindrical tube 9 on the target 31 side. Furthermore, as Figure 2 As shown, the exemplary X-ray passage hole 7a is provided in a wall portion 72, which is connected to the wall portion 71 and extends so as to intersect the Z-axis direction. The X-ray passage hole 7a penetrates the wall portion 72 along the Z-axis direction.

[0048] In some embodiments, if the diameters of the cylindrical portions 91 to 96 are represented by d1 to d6, the relationship "d2 > d3 > d1 > d4 > d5 > d6" holds. For example, diameter d1 is 6 to 12 mm, diameter d2 is 10 to 14 mm, diameter d3 is 8 to 12 mm, diameter d4 is 4 to 6 mm, diameter d5 is 4 to 6 mm, and diameter d6 is 0.5 to 4 mm.

[0049] At least a portion of the cylindrical portion 91 and the cylindrical portion 92 are located closer to the electron gun 2 than the portion of the electron passage P surrounded by the pole piece 42b of the magnetic focusing lens 42 (particularly, the gap between the yoke 42c and the yoke 42d). In some embodiments, at least a portion of the cylindrical portion 91 and the cylindrical portion 92 constitute "a portion of the electron passage P closer to the electron gun 2 than the portion surrounded by the pole piece 42b of the magnetic focusing lens 42" (hereinafter referred to as the "first cylindrical portion"). Furthermore, as described above, the diameter d2 of the cylindrical portion 92 is larger than the diameter d1 of the cylindrical portion 91 (d2 > d1). In other words, within the first cylindrical portion, at least a portion of the cylindrical portion 92 constitutes an expanded diameter portion, which expands toward the target 31.

[0050] The cylindrical portion 96 includes an end portion 9b on the target 31 side of the electron passage path P. Further, the diameter d6 of the cylindrical portion 96 is smaller than the diameter d5 of the cylindrical portion 95 (d6 < d5). That is, the diameter of the cylindrical portion 96 is reduced compared to the cylindrical portion 95 adjacent on the electron gun 2 side, and the cylindrical portion 96 constitutes a diameter-reducing portion that reduces in diameter toward the target 31 side. In several embodiments, the diameter d2 of the cylindrical portion 92 is the maximum diameter of the cylindrical tube 9, and the diameter is gradually reduced from the cylindrical portion 92 toward the target 31 side. Therefore, it can be understood that the above-described diameter-reducing portion is constituted by the portion including the cylindrical portions 93 to 96.

[0051] In several embodiments, the size of the electron beam EB is adjusted by the magnetic focusing lens 42 disposed at a stage posterior to the electron gun 2, and the cross-sectional shape of the electron beam EB is deformed into an elliptical shape by the magnetic quadrupole lens 43 disposed at a stage posterior to the magnetic focusing lens 42. Therefore, the adjustment of the size of the electron beam EB and the adjustment of the cross-sectional shape can be performed independently of each other.

[0052] Figure 4 of (A) includes Figure 1 and Figure 2 is a schematic view of a structural example of the magnetic focusing lens 42 and the magnetic quadrupole lens 43 shown. Figure 4 of (B) is a schematic view of the structure (doublet lens) of the comparative example. Figure 4 of (A) and (B) are diagrams schematically showing an example of an optical system acting on the electron beam EB between the cathode C (electron gun 2) and the target 31. In Figure 4 in the structure of the comparative example shown in (B), the size and the aspect ratio of the cross-sectional shape of the electron beam are adjusted by combining two magnetic quadrupole lenses in which the surface acting as a concave lens and the surface acting as a convex lens are interchanged with each other. In Figure 4 in the comparative example of (B), the lens that determines the size of the cross-sectional shape of the electron beam and the lens that determines the aspect ratio are not independent of each other. Therefore, it is necessary to reset the size and the aspect ratio simultaneously by combining two magnetic quadrupole lenses. Therefore, the adjustment of the focus size and the focus shape is complicated. In contrast, in Figure 4 in the structure of the embodiment shown in (A), the size of the cross-sectional shape of the electron beam EB is adjusted by the magnetic focusing lens 42 in the front stage. That is, by the magnetic focusing lens 42, the cross-sectional shape of the electron beam EB is narrowed to a certain size. Thereafter, the aspect ratio of the cross-sectional shape of the electron beam EB is adjusted by the magnetic quadrupole lens 43 in the rear stage. In this way, in Figure 4 in the structure of the embodiment of (A), the lens (magnetic focusing lens 42) that determines the size of the cross-sectional shape of the electron beam EB and the lens (magnetic quadrupole lens 43) that determines the aspect ratio are independent of each other. Therefore, the adjustment of the focus size and the focus shape can be easily and flexibly performed.

[0053] Furthermore, while the electron beam EB passing through the magnetic focusing lens 42 rotates about an axis along the X-axis, the cross-sectional shape of the electron beam EB emitted by the electron gun 2 is circular. Therefore, the cross-sectional shape of the electron beam EB that passes through the magnetic focusing lens 42 and reaches the magnetic quadrupole lens 43 is constant (circular) regardless of the amount of rotation of the electron beam EB within the magnetic focusing lens 42. Thus, within the magnetic quadrupole lens 43, the cross-sectional shape F1 (cross-sectional shape along the YZ plane) of the electron beam EB can be consistently and reliably shaped into an elliptical shape having a major diameter X1 along the Z-direction and a minor diameter X2 along the Y-axis. This makes it possible to easily and flexibly adjust the aspect ratio and size of the cross-sectional shape of the electron beam EB.

[0054] The performance of an X-ray generator 1 according to an embodiment of the present invention, which includes an electron gun 2 and a magnetic lens 4, was evaluated through experiments. A high voltage was applied to the electron gun 2, and the target 31 was set to ground potential. At the desired output (voltage applied to the cathode C), X-rays XR with an effective focal spot size of "40 μm × 40 μm" were obtained. Even when the focal spot size varied during 1000 hours of operation, the above-described effective focal spot size could be easily restored simply by adjusting the current flowing through the coil 43d of the magnetic quadrupole lens 43, without changing the operating conditions on the cathode C side. As described above, according to the X-ray generator 1, it was confirmed that the effective focal spot size of the X-rays XR could be easily corrected in response to dynamic changes simply by adjusting the current flowing through the coil 43d.

[0055] In several embodiments, such as Figure 5 As shown, the target 31 has an electron incident surface 31a on which the electron beam EB is incident. The electron incident surface 31a is tilted relative to the X-axis and Z-axis directions. Furthermore, the cross-sectional shape F1 (i.e., the ratio of the major diameter X1 to the minor diameter X2) of the electron beam EB after being deformed into an elliptical shape by the magnetic quadrupole lens 43, and the tilt angle of the electron incident surface 31a relative to the X-axis and Y-axis directions are adjusted so that the focal point shape F2 of the X-rays XR observed from the extraction direction (Z-axis direction) of the X-rays XR becomes approximately circular. In some embodiments, by adjusting the tilt angle of the electron incident surface 31a of the target 31 and the shaping conditions (aspect ratio) performed by the magnetic quadrupole lens 43, the shape of the focal point (effective focal point) of the extracted X-rays XR can be set to a approximately circular shape. As a result, an appropriate inspection image can be obtained in X-ray inspection, etc. using the X-rays XR generated by the X-ray generator 1.

[0056] In several embodiments, such as Figure 2As shown, the length of the magnetic focusing lens 42 along the X-axis direction is longer than the length of the magnetic quadrupole lens 43 along the X-axis direction. Here, the "length of the magnetic focusing lens 42 along the X-axis direction" refers to the total length of the yoke 42c surrounding the coil 42a. In some embodiments, it is easier to ensure the number of turns of the coil 42a of the magnetic focusing lens 42. As a result, by generating a relatively large magnetic field by the magnetic focusing lens 42, the reduction rate is further increased, thereby effectively focusing the electron beam EB to a smaller size. Furthermore, in order to reduce the size of the electron beam EB incident on the electron incident surface 31a of the target 31, the distance from the electron gun 2 to the center of the lens formed by the magnetic focusing lens 42 (the portion where the pole piece 42b is provided) can be lengthened.

[0057] In addition, the inner diameter D of the pole piece 42b of the magnetic focusing lens 42 is larger than the inner diameter d of the magnetic quadrupole lens 43 (refer to Figure 3 In some embodiments, by making the inner diameter D of the pole piece 42b of the magnetic focusing lens 42 relatively large, the spherical aberration of the lens formed by the magnetic focusing lens 42 can be reduced. Furthermore, by making the inner diameter d of the magnetic quadrupole lens 43 relatively small, the number of turns of the coil 43d of the magnetic quadrupole lens 43 and the amount of current flowing through the coil 43d can be reduced. As a result, the heat generated by the magnetic quadrupole lens 43 can be suppressed.

[0058] The X-ray generator 1 also includes a cylindrical tube 9 extending along the X-axis and forming an electron passage P for the electron beam EB. Furthermore, the magnetic focusing lens 42 and the magnetic quadrupole lens 43 are directly or indirectly connected to the cylindrical tube 9. In some embodiments, the magnetic focusing lens 42 and the magnetic quadrupole lens 43 can be positioned or mounted using the cylindrical tube 9 as a reference. This allows the central axes of the magnetic focusing lens 42 and the magnetic quadrupole lens 43 to be precisely aligned on the same axis. As a result, deformation of the outline (cross-sectional shape) of the electron beam EB after passing through the magnetic focusing lens 42 and the magnetic quadrupole lens 43 can be suppressed.

[0059] The X-ray generator 1 also includes a deflection coil 41. In some embodiments, as described above, the angular offset between the emission axis of the electron beam EB emitted from the electron gun 2 and the central axes of the magnetic focusing lens 42 and the magnetic quadrupole lens 43 can be appropriately corrected. Furthermore, the deflection coil 41 is disposed between the electron gun 2 and the magnetic focusing lens 42. In some embodiments, the direction of travel of the electron beam EB can be appropriately adjusted before the electron beam EB passes through the magnetic focusing lens 42 and the magnetic quadrupole lens 43. As a result, the cross-sectional shape of the electron beam EB incident on the target 31 can be maintained at a desired elliptical shape.

[0060] In the X-ray generator 1, an electron passage P is formed, extending through the housing 6 that houses the cathode C (electron gun 2) and the housing 7 that houses the target 31. Furthermore, the portion of the electron passage P that includes the end portion on the target 31 side (end portion 9b of the cylindrical tube 9) tapers in diameter toward the target 31. In some embodiments, the cylindrical portion 96 (or cylindrical portions 93 to 96) forms a reduced diameter portion that tapers toward the target 31. This makes it difficult for reflected electrons generated within the housing 7 by the electron beam EB incident on the target 31 to reach the housing 6 via the electron passage P. As a result, deterioration of the cathode C caused by reflected electrons emitted from the target 31 can be suppressed or prevented. The term "reflected electrons" refers to electrons in the electron beam EB incident on the target 31 that are not absorbed by the target 31 and are reflected therefrom.

[0061] When the electron beam EB is emitted from the cathode C, gas is generated by the electron gun 2. Gas may remain in the space containing the cathode C. In addition, gas (for example, gaseous byproducts such as H2, H2O, N2, CO, CO2, CH4, Ar, etc.) is generated in the frame 7 due to the collision of electrons with the target 31. As a result, electrons may be reflected from the surface of the target 31. In some embodiments, since the entrance (i.e., the end 9b) on the target 31 side of the electron passage path P is narrowed, less gas is attracted toward the frame 6 side (i.e., the internal space S1) through the electron passage path P, and thus less gas is discharged from the exhaust flow path E1 provided in the frame 6. Therefore, in the X-ray generating device 1, the exhaust path (exhaust flow path E2) for the above-mentioned gas is provided in the frame 7 itself. As a result, vacuum exhaust in each frame 6 and 7 can be appropriately performed, and degradation of the cathode C due to reflected electrons can be suppressed or prevented.

[0062] Furthermore, the portion of the electron passage P closer to the electron gun 2 than the portion surrounded by the pole piece 42b of the magnetic focusing lens 42 (the aforementioned first cylindrical portion) has an expanded diameter portion (at least a portion of the cylindrical portion 92) whose diameter increases toward the target 31. In some embodiments, even if reflected electrons enter the electron passage P from the end 9b of the electron passage P on the target 31 side, the expanded diameter portion that increases toward the target 31 (i.e., the portion that decreases toward the cathode C) can suppress the reflected electrons from traveling through the electron passage P toward the cathode C. Furthermore, the electron beam EB bound for the target 31 can be effectively suppressed from colliding with the inner wall of the electron passage P (the inner surface of the cylindrical tube 9).

[0063] Furthermore, the diameter-enlarged portion of the cylindrical tube 9, which extends from the electron gun 2 side toward the target 31 side, includes a portion (i.e., the boundary between the cylindrical portion 91 and the cylindrical portion 92) that discontinuously changes from a portion having a diameter d1 (first diameter) (i.e., the cylindrical portion 91) toward a portion having a diameter d2 (second diameter) larger than the diameter d1 (i.e., the cylindrical portion 92). In some embodiments, the diameter of the cylindrical tube 9 changes in a stepwise manner at the boundary between the cylindrical portion 91 and the cylindrical portion 92. The boundary portion 9c is formed by an annular wall having an inner diameter of the diameter d1 and an outer diameter of the diameter d2 (see FIG. 1 ). Figure 2 In some embodiments, even if there are reflected electrons traveling from the target 31 toward the electron gun 2 within the electron passage P, the reflected electrons can be caused to collide with the boundary portion 9c. This can more effectively suppress or prevent the reflected electrons from moving toward the cathode C.

[0064] Furthermore, the diameter of the portion of the electron passage P surrounded by the pole piece 42b of the magnetic focusing lens 42 (diameter d2 of the cylindrical portion 92) is greater than the diameter of the remaining portion of the electron passage P. In other words, the electron passage P has its maximum diameter in the portion surrounded by the pole piece 42b of the magnetic focusing lens 42. In some embodiments, by increasing the diameter of the portion where the electron beam EB emitted from the electron gun 2 diverges more (i.e., the portion surrounded by the pole piece 42b) to be greater than the diameter of the remaining portion, the electron beam EB directed toward the target 31 can be effectively suppressed from colliding with the inner wall of the electron passage P (the inner surface of the cylindrical tube 9).

[0065] Furthermore, the exhaust flow path E1 communicates with the exhaust flow path E2. Furthermore, the exhaust unit 5 evacuates the interior of the housing 6 via the exhaust flow path E1 and the interior of the housing 7 via the exhaust flow path E2. In some embodiments, the shared exhaust unit 5 can be used to evacuate both the internal space S1 within the housing 6 and the internal space S2 within the housing 7, thereby miniaturizing the X-ray generator 1.

[0066] It should be understood that all aspects, advantages, and features described in this specification are not necessarily achieved by, or included in, any specific embodiment. In this specification, various embodiments are described, but it should be clear that other embodiments including different materials and shapes may also be adopted.

[0067] For example, if the emission axis of the electron beam EB from the electron gun 2 is accurately aligned with the central axis of the magnetic focusing lens 42, the deflection coil 41 can be omitted. Alternatively, the deflection coil 41 can be disposed between the magnetic focusing lens 42 and the magnetic quadrupole lens 43, or between the magnetic quadrupole lens 43 and the target 31.

[0068] The shape of the electron passage path P (cylindrical tube 9) can have a single diameter throughout the entire structure. In addition, the electron passage path P can be formed by a single cylindrical tube 9. In other examples, the cylindrical tube 9 can be provided only in the frame 6, and the electron passage path P passing through the frame 7 can be formed by a through-hole provided in the wall portion 71 of the frame 7. In addition, the cylindrical tube 9 can be omitted and the electron passage path P can be formed by the through-hole of the tubular member 10 and the through-holes provided in the frame 44 and the frame 7.

[0069] Figure 6 The first variation of the cylindrical tube (cylindrical tube 9A) is shown. In some embodiments, the cylindrical tube 9A has cylindrical portions 91A to 93A instead of the cylindrical portions 91 to 96. Figure 2 The cylindrical tube 9 shown is different. The cylindrical portion 91A extends from the end 9a of the cylindrical tube 9 to the position of the coil 42a surrounded by the electron gun 2 side. The cylindrical portion 91A has a conical shape. For example, the diameter of the cylindrical portion 91A gradually increases from the diameter d1 to the diameter d2 from the end 9a toward the target 31 side. The cylindrical portion 92A extends from the end of the cylindrical portion 91A on the target 31 side to a position slightly closer to the target 31 side than the pole piece 42b. The cylindrical portion 92A has a certain diameter (diameter d2). The cylindrical portion 93A extends from the end of the cylindrical portion 92A on the target 31 side to the end 9b of the cylindrical tube 9. The cylindrical portion 93A has a conical shape. For example, the diameter of the cylindrical portion 93A gradually decreases from the diameter d2 to the diameter d6 from the end of the cylindrical portion 92A toward the target 31 side. In the cylindrical tube 9A, the cylindrical portion 91A corresponds to the diameter expansion portion, and the cylindrical portion 93A corresponds to the diameter reduction portion.

[0070] Figure 7 The second variation of the cylindrical tube (cylindrical tube 9B) is shown. In some embodiments, the cylindrical tube 9B has cylindrical portions 91B and 92B instead of the cylindrical portions 91 to 96. Figure 2 The cylindrical tube 9 shown is different. The cylindrical portion 91B extends from the end 9a of the cylindrical tube 9 to a position surrounded by the pole piece 42b. The cylindrical portion 91B has a tapered shape. For example, the diameter of the cylindrical portion 91B gradually increases from the diameter d1 to the diameter d2 from the end 9a toward the target 31 side. The cylindrical portion 92B extends from the end of the cylindrical portion 91B on the target 31 side to the end 9b of the cylindrical tube 9. The cylindrical portion 92B has a tapered shape. In some embodiments, the diameter of the cylindrical portion 92B gradually decreases from the diameter d2 to the diameter d6 from the end of the cylindrical portion 91B toward the target 31 side. In the cylindrical tube 9B, the cylindrical portion 91B corresponds to the diameter-expanding portion, and the cylindrical portion 92B corresponds to the diameter-reducing portion.

[0071] In some embodiments, the reduced diameter portion and the expanded diameter portion of the cylindrical tube (the path through which electrons pass) may not be formed in a stepped (non-continuous) manner as in cylindrical tube 9, but may be formed in a tapered shape as in cylindrical tubes 9A and 9B. Alternatively, as in cylindrical tube 9B, the cylindrical tube may consist solely of a tapered portion. Furthermore, the cylindrical tube may have both a portion that changes in diameter in a stepped manner and a portion that changes in diameter in a tapered manner. For example, the expanded diameter portion may be tapered as in cylindrical tube 9A, while the reduced diameter portion may be stepped as in cylindrical tube 9.

[0072] Furthermore, the target does not need to be a rotating anode. In some embodiments, the target may not rotate, and the electron beam EB may always be incident on the same position on the target. However, by using the target as a rotating anode, the local load on the target caused by the electron beam EB can be reduced. As a result, the amount of the electron beam EB can be increased, and the amount of X-rays XR emitted from the target can be increased.

[0073] In some embodiments, the electron gun 2 may be configured to emit an electron beam EB having a circular cross-sectional shape. In other examples, the electron gun 2 may be configured to emit an electron beam having a cross-sectional shape other than a circular shape.

[0074] [Note]

[0075] The present disclosure includes the following structures.

[0076] [Structure 1]

[0077] The direction of travel of the electron beam EB is adjusted by correcting the angular offset between the axis of the electron beam EB in the first direction (X-axis direction) and the central axis of the electron path P passing through the magnetic focusing lens 42 and the magnetic quadrupole lens 43 through the deflection coil 41 (when the deflection coil 41 includes two deflection coils, it is one deflection coil).

[0078] [Structure 2]

[0079] The direction of travel of the electron beam EB is further adjusted by a second deflection coil (another deflection coil when the deflection coil 41 includes two deflection coils) arranged between the electron gun 2 and the magnetic focusing lens 42 in such a way as to correct the lateral offset between the axis of the electron beam EB and the central axis of the electron passage path P.

[0080] [Structure 3]

[0081] The X-ray generating device 1 includes: a means for emitting an electron beam EB having a circular cross-sectional shape (for example, an electron gun 2), a means for focusing the electron beam EB while rotating it around a rotation axis (for example, a magnetic focusing lens 42), a means for deforming the circular cross-sectional shape of the electron beam EB into an elliptical cross-sectional shape having a major diameter X1 orthogonal to the rotation axis and a minor diameter X2 orthogonal to both the rotation axis and the major diameter X1 (for example, a magnetic quadrupole lens 43), and a means for emitting X-rays XR based on receiving the electron beam EB having an elliptical cross-sectional shape (for example, a target 31).

[0082] [Structure 4]

[0083] The X-ray generator 1 further includes means for adjusting the direction of travel of the electron beam EB (e.g., a deflection coil 41). The means for adjusting the direction of travel of the electron beam EB is located between the means for emitting the electron beam EB (the electron gun 2) and the means for focusing the electron beam (the magnetic focusing lens 42).

[0084] [Structure 5]

[0085] The means for focusing the electron beam includes a first magnetic lens (magnetic focusing lens 42). The means for deforming the cross-sectional shape of the electron beam includes a second magnetic lens (magnetic quadrupole lens 43). The adjustment means include means for correcting the angular offset between the rotation axis of the electron beam EB and the central axis passing through both the first and second magnetic lenses (e.g., one of the two deflection coils included in the deflection coil 41), and means for correcting the lateral offset between the rotation axis of the electron beam EB and the central axis (e.g., the other of the two deflection coils included in the deflection coil 41).

[0086] [Structure 6]

[0087] The means for emitting X-rays XR (target 31) has an electron incident surface 31a tilted relative to both the major axis X1 and the minor axis X2. The X-ray generator 1 includes means (magnetic quadrupole lens 43) for adjusting the ratio of the major axis X1 to the minor axis X2 of the electron beam EB after deforming the circular cross-sectional shape of the electron beam EB into an elliptical cross-sectional shape. The combination of this ratio and the tilt angle of the electron incident surface 31a relative to the major axis X1 and the minor axis X2 determines the substantially circular focal shape F2 of the X-rays XR as viewed from the direction of X-ray XR extraction (Z-axis direction).

[0088] [Structure 7]

[0089] The X-ray generating method includes: a step of emitting an electron beam EB having a circular cross-sectional shape; a step of focusing the electron beam EB having a circular cross-sectional shape while rotating it around a rotation axis through a first magnetic lens; a step of deforming the circular cross-sectional shape of the electron beam EB into an elliptical cross-sectional shape having a long diameter X1 orthogonal to the rotation axis and a short diameter X2 orthogonal to both the rotation axis and the long diameter X1 through a second magnetic lens; and a step of emitting X-rays XR based on receiving the electron beam EB having an elliptical cross-sectional shape with a target 31.

[0090] [Structure 8]

[0091] The second magnetic lens includes a magnetic quadrupole lens 43 .

[0092] [Structure 9]

[0093] The magnetic quadrupole lens 43 deforms the circular cross-sectional shape of the electron beam EB into an elliptical cross-sectional shape after the electron beam EB having the circular cross-sectional shape is focused by the first magnetic lens.

[0094] [Structure 10]

[0095] The X-ray generating method further includes the step of adjusting the traveling direction of the electron beam EB having a circular cross-sectional shape before the electron beam EB is focused by the first magnetic lens.

[0096] [Structure 11]

[0097] The traveling direction of the electron beam EB is adjusted by a deflection yoke 41 that corrects an angular deviation between the rotation axis of the electron beam EB and the central axis passing through both the first magnetic lens and the second magnetic lens.

[0098] [Structure 12]

[0099] The traveling direction of the electron beam EB is adjusted by a deflection yoke 41 that corrects a lateral deviation between the rotation axis of the electron beam EB and the central axis passing through both the first magnetic lens and the second magnetic lens.

[0100] [Structure 12]

[0101] The target 31 has an electron incident surface 31a that is tilted relative to both the major axis X1 and the minor axis X2. The X-ray generation method further comprises the following steps: after deforming the circular cross-sectional shape of the electron beam EB into an elliptical cross-sectional shape, adjusting the ratio of the major axis X1 to the minor axis X2 of the electron beam EB. The combination of this ratio and the tilt angle of the electron incident surface 31a relative to the major axis X1 and the minor axis X2 determines the substantially circular focal shape F2 of the X-rays XR as viewed from the extraction direction (Z-axis direction) of the X-rays XR.

Claims

1. An X-ray generating device, wherein: have: an electron gun emitting an electron beam having a circular cross-sectional shape; a magnetic focusing lens disposed at a rear portion of the electron gun and configured to focus the electron beam while rotating the electron beam about an axis extending in a first direction; a magnetic quadrupole lens disposed at a rear portion of the magnetic focusing lens and configured to deform the circular cross-sectional shape of the electron beam into an elliptical cross-sectional shape having a major axis along a second direction perpendicular to the first direction and a minor axis along a third direction perpendicular to both the first and second directions; a cylindrical tube extending along the first direction and forming an electron passage path through which the electron beam passes, wherein the maximum diameter of the inner diameter of the cylindrical tube in a portion surrounded by the magnetic focusing lens is larger than the maximum diameter of the inner diameter of the cylindrical tube in a portion surrounded by the magnetic quadrupole lens; and The target is arranged at a stage behind the magnetic quadrupole lens and emits X-rays in response to the incidence of the electron beam.

2. The X-ray generating device according to claim 1, wherein: The target has an electron incident surface on which the electron beam is incident, The electron incident surface is inclined with respect to the first direction and the second direction, The roughly circular focus shape of the X-ray observed from the X-ray extraction direction is determined by the ratio of the major axis to the minor axis of the electron beam after being deformed into the elliptical cross-sectional shape by using the magnetic quadrupole lens and the inclination angle of the electron incident surface relative to the first direction and the second direction.

3. The X-ray generating device according to claim 1, wherein: A length of the magnetic focusing lens along the first direction is longer than a length of the magnetic quadrupole lens along the first direction.

4. The X-ray generating device according to claim 1, wherein: The inner diameter of the pole piece of the magnetic focusing lens is larger than the inner diameter of the magnetic quadrupole lens.

5. The X-ray generating device according to claim 1, wherein: The magnetic focusing lens and the magnetic quadrupole lens are directly or indirectly connected to the cylindrical tube.

6. The X-ray generating device according to claim 1, wherein: The device further includes a deflection yoke for adjusting the traveling direction of the electron beam.

7. The X-ray generating device according to claim 6, wherein: The deflection coil is arranged between the electron gun and the magnetic focusing lens. The maximum diameter of the inner diameter of the cylindrical tube at a portion surrounded by the deflection yoke is smaller than the maximum diameter of the inner diameter of the cylindrical tube at a portion surrounded by the magnetic focusing lens.

8. The X-ray generating device according to claim 7, wherein: The traveling direction of the electron beam is adjusted by the deflection yoke to correct an angular deviation between the axis of the electron beam in the first direction and the central axis of the electron passage through the magnetic focusing lens and the magnetic quadrupole lens.

9. The X-ray generating device according to claim 8, wherein: The traveling direction of the electron beam is further adjusted by a second deflection coil disposed between the electron gun and the magnetic focusing lens to correct a lateral offset between the axis of the electron beam and the central axis of the electron passage.

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