JP2016051629A - X-ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide neutral grounding type and anode grounding type X-ray tube assembly, in which heating of an X-ray radiation window can be reduced.SOLUTION: An X-ray tube assembly includes an emitter to which a negative high voltage is applied, and emitting an electron beam, an anode target to which a positive high voltage for the cathode is applied, and installed to face the cathode, while having a target surface where a focus for emitting X-ray when an electron beam impinges thereon is formed, a vacuum envelope for housing the cathode and anode targets in vacuum-tight, a radiation window formed in a part of the wall surface of the vacuum envelope having potential higher than that of the cathode, and allowing the X-ray emitted from the anode target to be radiated to the outside, and an electrode member of the same potential as the cathode installed between the focus and radiation window, and reflecting some rebound electrons reflected on the focus.SELECTED DRAWING: Figure 1

Description

  Embodiments relate to an X-ray tube apparatus.

  The X-ray tube apparatus includes an X-ray tube having a cathode and an anode target. X-ray tube apparatuses are used in medical diagnostic apparatuses, industrial nondestructive inspection apparatuses, or material analysis apparatuses.

  In a conventional X-ray tube apparatus, an electron beam emitted from a cathode is accelerated and focused by a potential gradient between the cathode and the anode target. Typically, the electron beam collides with the target surface of the anode target at an energy of 20 to 150 keV substantially perpendicularly (90 ° ± 20 °), and forms a focal point as an X-ray generation source on the anode target. When an electron beam having high energy strikes the focal point, the electron beam is rapidly decelerated by the target material, so that X-rays are emitted. The rate at which the electron beam is converted to X-rays is only 1% or less of the kinetic energy of the electrons that strike the anode target. The remaining kinetic energy is converted to heat. The emitted X-rays are emitted from the X-ray emission window to the outside. A part of the electrons recoiled by the anode target is bounced back by the inner wall of the vacuum envelope, and is again struck by the anode target. Further, in the X-ray tube apparatus of neutral point grounding and anode grounding type, a part of the recoil electrons impacts the X-ray radiation window.

JP 2013-137987 A JP 2014-35977 A

  In the X-ray tube device, since the potential of the X-ray emission window is higher than that of the cathode, recoil electrons recoiled in the direction of the X-ray emission window impact the X-ray emission window. When the recoil electrons are bombarded, the X-ray emission window is heated to a high temperature state.

  The problem to be solved by the embodiments of the present invention is to provide an X-ray tube apparatus of neutral point grounding and anode grounding type that can reduce heating of the X-ray radiation window.

  An X-ray tube apparatus according to an embodiment of the present invention has a negative high voltage applied thereto, a cathode having an emission source that emits an electron beam, a positive high voltage applied to the cathode, and facing the cathode. An anode target having a target surface on which a focal point for emitting X-rays is formed when an electron beam is incident; a vacuum envelope that houses the cathode and the anode target in a vacuum-tight manner; and a higher potential than the cathode A radiation window portion that is formed on a part of the wall surface portion of the vacuum envelope and allows radiation of X-rays emitted from the anode target to the outside, and is at the same potential as the cathode and between the focal point and the radiation window portion And an electrode member that reflects some recoil electrons reflected at the focal point.

FIG. 1 is a schematic diagram illustrating the principle of X-ray generation in the X-ray tube apparatus according to the first embodiment. FIG. 2 is a schematic view showing a cross section of the X-ray tube apparatus taken along line II-II in FIG. FIG. 3 is a cross-sectional view showing a detailed structure of the X-ray tube apparatus according to the first embodiment. 4 is a cross-sectional view of the X-ray tube device taken along line IV-IV in FIG. FIG. 5 is a schematic diagram of an X-ray tube apparatus according to a modification of the first embodiment. FIG. 6 is a schematic diagram illustrating the principle of X-ray generation in the X-ray tube apparatus according to the second embodiment. FIG. 7 is a cross-sectional view of the X-ray tube device taken along line VII-VII in FIG. FIG. 8 is a cross-sectional view showing a detailed structure of the X-ray tube apparatus according to the second embodiment. FIG. 9 is a cross-sectional view of the X-ray tube apparatus taken along line IX-IX in FIG. FIG. 10 is a perspective view schematically showing the external appearance of the X-ray tube and the first magnetic deflection unit in the X-ray tube apparatus shown in FIG. FIG. 11 is a schematic diagram of an X-ray tube apparatus according to a modification of the second embodiment. FIG. 12 is a schematic diagram illustrating the principle of X-ray generation in the X-ray tube apparatus according to the third embodiment. FIG. 13 is a schematic diagram showing a cross section of the X-ray tube apparatus taken along line XIII-XIII in FIG. FIG. 14 is a cross-sectional view of the X-ray tube apparatus according to the third embodiment taken along line IV-IV. FIG. 15 is a perspective view schematically showing the external appearance of the X-ray tube and the second magnetic deflection unit in the X-ray tube apparatus shown in FIG. FIG. 16 is a schematic diagram of an X-ray tube apparatus according to a modification of the third embodiment. FIG. 17 is a schematic diagram illustrating the principle of X-ray generation in the X-ray tube apparatus according to the fourth embodiment. FIG. 18 is a schematic diagram showing a cross section of the X-ray tube device taken along line XVIII-XVIII in FIG. FIG. 19 is a perspective view schematically showing the external appearance of the X-ray tube and the first and second magnetic deflection units in the X-ray tube apparatus of the fourth embodiment.

Hereinafter, an X-ray tube apparatus according to an embodiment will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic diagram showing the principle of generation of X-rays in the X-ray tube apparatus according to the first embodiment, and shows the arrangement of components in a plane orthogonal to the target surface. FIG. 2 is a cross-sectional view of the X-ray tube apparatus taken along line II-II in FIG. 1, and the front configuration of the X-ray tube apparatus is shown in FIG.

  First, the basic operation principle of the X-ray tube apparatus 10 will be described with reference to FIGS. 1 and 2. The X-ray tube apparatus 10 includes high-voltage power supplies 15A and 15B and an X-ray tube 30 when roughly classified. Although details will be described later, the X-ray tube 30 includes a vacuum envelope 31, a vacuum container 32 including a side wall 32 a, an X-ray emission window portion 33, an anode target 35, and a cathode 36. In the present embodiment, the X-ray tube 30 is a neutral point ground tube. The high voltage power supplies 15 </ b> A and 15 </ b> B cause a potential difference between the anode target 35 and the cathode 36. In the present embodiment, the high voltage power supply 15 </ b> A applies a high voltage (negative high voltage) only to the cathode 36. The high voltage power supply 15 </ b> A applies a voltage of −V to the cathode 36. The high voltage power supply 15 </ b> B applies a high voltage (positive high voltage) only to the anode target 35. The high voltage power supply 15 </ b> B applies a voltage of + V to the anode target 35. For example, a negative high voltage of −70 kV is applied to the cathode, and a positive high voltage of +70 kV is applied to the anode target 35.

  The cathode 36 has an electron emission source 36 a having an emission source for emitting electrons, a focusing electrode (focusing cup) 36 b, and a reflection electrode (electrode member) 136. The electron emission source 36a is supplied with a current and emits an electron beam in the first direction d1. In the present embodiment, the first direction d1 is a direction perpendicular to the emission surface for emitting electrons in the electron emission source 36a. The focusing electrode 36b focuses the electron beam and shapes (optimizes) the electron beam (electron distribution shape). A negative voltage is applied to the cathode 36 relative to the anode target 35. The voltage applied to the cathode 36 is also applied to the electron emission source 36a. A voltage is applied to the focusing electrode 36b to shape the electron beam. When the voltage applied to the focusing electrode 36b is changed, the shape of the generated electron beam can be changed. For example, a voltage of 10 kV or less is applied to the focusing electrode 36b.

  The reflective electrode 136 includes a window part (reflective member) 136a for transmitting X-rays at one end part (tip part). The reflective electrode 136 and the window 136a are formed of a long conductive member. For example, the reflective electrode 136 and the window 136a are formed of the same metal as the cathode 36. As shown in FIGS. 1 and 2, the reflective electrode 136 has a window 136a disposed between the X-ray emission window 33 and the anode target 35 (focal point F described later), and an end opposite to the window 136a. The unit is installed so as to be connected to the cathode 36. Therefore, the reflective electrode 136 and the window portion 136a have substantially the same potential as the cathode 36, and preferably have the same potential as the cathode 36.

  As shown in FIG. 2, the window 136a of the reflective electrode 136 has a predetermined thickness (hereinafter referred to as thickness) in a direction parallel to the direction in which X-rays are emitted (second direction d2 described later). And has a predetermined width (hereinafter referred to as a width) in the vertical direction. The window 136a of the reflective electrode 136 is formed in the reflective electrode 136 as a hole penetrating in a circular shape. For example, the reflective electrode 136 is formed with a diameter equal to or smaller than that of the X-ray emission window 33 described later. The reflective electrode 136 may be formed of a member that transmits X-rays. In that case, the window 136a may not be provided in the reflective electrode 136.

  The anode target 35 includes a target surface 35b. The target surface 35 b is formed so as to have an inclination so as to reflect X-rays in the direction of the X-ray radiation window portion 33. The target surface 35b is formed with a focal point F where an electron beam is incident from the first direction d1. When electrons enter the focal point F, X-rays are emitted from the anode target 35. X-rays are emitted in all directions, but many X-rays are emitted in the direction of the X-ray emission window 33. Here, a direction orthogonal to the first direction d1 and toward the X-ray emission window 33 side is referred to as a second direction d2. Many X-rays are emitted in the second direction d2. In addition, some of the electrons impacting the focal point F of the anode target 35 are scattered as recoil electrons.

Hereinafter, the detailed structure of the X-ray tube apparatus 10 according to the present embodiment will be described with reference to FIGS. 3 and 4.
FIG. 3 is a sectional view showing a detailed structure of the X-ray tube apparatus. FIG. 4 is a cross-sectional view of the X-ray tube apparatus taken along line IV-IV in FIG.

  With reference to FIG.3 and FIG.4, the structure of the X-ray tube apparatus 10 is demonstrated in detail. The X-ray tube apparatus 10 further includes a housing 20, a high voltage insulating member 40, a voltage supply terminal 44, a high voltage connector 300, a stator coil 910, a rotor 920, a bearing 930, a fixed shaft 950, And a rotating body 960. Here, the stator coil 910 generates a magnetic field toward the rotor 920 and rotates the rotor 920. The rotating body 960 is fixed to a rotor 920 connected to the anode target 35, and the anode target 35 is rotated as the rotor 920 rotates.

  The housing 20 includes a cylindrical housing body 20a and a lid portion 20b that seals the housing body 20a. The housing body 20a has, for example, an X-ray emission window 24 that allows X-ray emission. The open end of the housing body 20a is closed with a lid portion 20b. The housing body 20a and the lid 20b are fastened and fixed by a fastener (not shown). A gap between the housing main body 20a and the lid portion 20b is liquid-tightly sealed by an O-ring (not shown). This O-ring prevents leakage of the coolant 6 from the inside of the housing 20 to the outside. The lid 20 b is provided with a pressure adjusting mechanism for the coolant 6, for example, a rubber bellows (rubber film) 21, and the pressure of the coolant 6 is adjusted by the rubber bellows (rubber film) 21.

  Note that the X-ray emission window 24 may be provided in the lid portion 20b instead of the housing body 20a. The rubber bellows 21 may be provided on the housing body 20a instead of the lid portion 20b.

  The support member 25 that supports the X-ray tube 30 on the housing 20 is fitted into the end of the housing main body 20a opposite to the lid 20b. The support member 25 is formed in an annular shape. The support member 25 supports a high voltage insulating member 40 which will be described later, and is fixed to the housing 20 in a liquid-tight manner.

  As described above, the X-ray tube 30 includes the vacuum envelope 31, the anode target 35, and the cathode 36. In the X-ray tube 30, a tube voltage V is applied between the cathode 36 and the anode target 35. When the potential of the anode target 35 is VA and the potential of the cathode 36 is VC, the tube voltage V corresponds to a potential difference (VA−VC). Usually, the tube voltage V is set to 20 kV to 150 kV.

  The vacuum envelope 31 contains an anode target 35 and a cathode 36. The vacuum envelope 31 has an inner surface portion 34, and includes a vacuum vessel 32, an X-ray radiation window portion 33, an insulating member 38, a mold insulating member 39, a high voltage insulating member 40, and a voltage supply terminal 54. And a KOV member 55. The inside of the vacuum envelope 31 is maintained in a vacuum state.

  The vacuum vessel 32 has a side wall 32a and a peripheral wall 32b. The vacuum vessel 32 is made of copper. In addition, for example, the vacuum vessel 32 (vacuum envelope 31) may be formed of a nonmagnetic metal such as stainless steel or aluminum, or an insulator such as glass or ceramics.

  The X-ray radiation window 33 is provided in an airtight manner in the opening of the side wall 32 a of the vacuum vessel 32. That is, the X-ray radiation window 33 is installed on the space side where many recoil electrons are scattered. The X-ray radiation window 33 is formed of a member that transmits the utilization X-ray flux. The X-ray emission window 33 is made of beryllium, for example. In the present embodiment, the X-ray emission window 33 may be formed of a material that is less expensive than beryllium. For example, the X-ray radiation window portion 33 may be formed with any one of aluminum, titanium, nickel, stainless steel, chromium steel, and iron alloy as a main component. For example, the X-ray emission window 33 is formed in a disc shape. As shown in FIGS. 1 and 2, the X-ray emission window 33 is formed with a diameter D1. The X-ray radiation window 33 has a thickness in a direction (d2) through which X-rays are transmitted, and the thickness is set to 0.1 to 3 mm, for example.

  The inner surface portion 34 forms an inner surface on the vacuum side of a region including the side wall 32 a and the X-ray radiation window portion 33. Here, the inner surface portion 34 is made of metal and is grounded (0 V). In the present embodiment, the inner surface portion 34 has a higher potential than the cathode 36. For example, when a negative high voltage is applied to the cathode 36, the inner surface portion 34 is at the ground potential.

  The insulating member 38 forms a part of the vacuum envelope 31. A voltage supply terminal 54 is fixed to the insulating member 38. The voltage supply terminal 54 is provided through the insulating member 38. The voltage supply terminal 54 is supported by a KOV member 55 that is a low expansion alloy. The KOV member 55 is provided between the cathode 36 and the insulating member 38. Both ends of the KOV member 55 are joined to the cathode 36 or the insulating member 38 by brazing. The voltage supply terminal 54 is covered with a mold insulating member 39. The mold insulating member 39 is laminated on the insulating member 38 so as to be in close contact with the insulating member 38 outside the vacuum vessel 32. The mold insulating member 39 is formed of a mold insulating member such as an epoxy resin. The voltage supply terminal 54 is connected to the cable 202 inside the mold insulating member 39. The cable 202 extends to the outside of the housing 20. The cathode voltage and the cathode current are applied to the cathode 36 from the cable 202 via the voltage supply terminal 54 and are supplied to the cathode 36.

  The high voltage insulating member 40 forms a part of the vacuum envelope 31. The high voltage insulating member 40 includes a cylindrical portion 46 having a cavity, a bottom portion 47 that narrows a space in the cavity of the cylindrical portion 46, and an external end surface portion 48 that is connected to the bottom portion 47. A stator coil 910, a rotor 920, a bearing 930, a fixed shaft 950, and a rotating body 960, which will be described later, are disposed in the hollow portion of the cylindrical portion 46. The cylindrical portion 46 has an open end on the side opposite to the one end on which the bottom 47 is provided, and the anode target 35 is disposed in the vacuum envelope 3 connected to the open end. Yes. The outer end surface portion 48 is formed so as to have a hollow at the substantially center thereof and to have a flat end surface on the outer side. A voltage supply terminal 44 is provided in the cavity of the external end face portion 48 so as to extend in the cavity. The voltage supply terminal 44 is fixed to a fixed shaft 950 described later. The voltage supply terminal 44 supplies a high voltage to the anode target via the fixed shaft 950.

  The detailed structure of the anode target 35 will be described. The anode target 35 is formed in a substantially disk shape. The anode target 35 includes a target layer 35a having a target surface 35b and a capturing surface 35d that captures recoil electrons, and is connected to the connecting portion 35c. The anode target 35 is made of a metal such as a molybdenum alloy. A positive voltage is applied to the anode target 35 with respect to the cathode 36.

  The anode target 35 is connected to the rotating body 960 through the connection portion 35c. The anode target 35 rotates with the rotating body 960. The rotating body 960 is formed in a cylindrical shape. The rotating body 960 is provided with a bearing 930 and a fixed shaft 950 on the inner side, and a rotor 920 on the outer side. The fixed shaft 950 is formed in a columnar shape and is fixed to the high voltage insulating member 40. The fixed shaft 950 supports the rotating body 960 via a bearing 930 so as to be rotatable. The rotor 920 is provided inside a cylindrical stator coil 910. By supplying a current to the stator coil 910 that is a rotation drive device, the rotor 920 rotates and the anode target 35 rotates.

  The target layer 35a is a layer of the anode target 35 in the direction facing the cathode 36 (first direction d1). The target layer 35a is formed of a metal having a melting point higher than that of the anode target 35 such as a tungsten alloy. When the electron beam is incident on the target layer 35a from the first direction d1, a focal point F that emits a utilization X-ray flux in the second direction d2 is formed as shown in FIG.

  The target surface 35b faces the cathode 36. The target surface 35b is formed as a part of the outer surface of the anode target 35, and is formed, for example, at the edge of a circle of the anode target 35. The target surface 35b has, for example, an inclination that rises from the edge of the circle toward the center. When the electron beam is incident on the target surface 35b from the first direction d1, a focal point F that emits X-ray flux (utilized X-rays) in the second direction d2 on the side where many recoil electrons are scattered. It is formed. Here, the used X-rays are X-rays emitted to the outside of the X-ray tube apparatus 10 and used by the user. The second direction d2 is determined as a direction substantially parallel to the traveling direction of the X-rays that passes through the center of the used X-ray bundle.

The connection part 35c supplies the anode target 35 with the high voltage applied via the rotary body 960 mentioned later.
The capture surface 35 d that captures recoil electrons extends from the target surface 35 b in the direction opposite to the cathode 36, and is formed so as to give a side surface to the anode target 35 that faces the X-ray emission window portion 33. The capturing surface 35d is formed to have an inclination, for example. The capture surface 35d captures recoil electrons. For example, recoil electrons reflected by the reflective electrode 136 impact the capture surface 35d.

  Next, the structure of the cathode 36 will be described in detail. As shown in FIG. 1, the cathode 36 includes an electron emission source 36 a, a focusing electrode (focusing cup) 36 b, and a reflection electrode 136. The electron emission source 36a emits an electron beam in the first direction d1. The electron emission source 36a is formed of a flat or coil filament. The focusing electrode 36b is formed in an annular shape and surrounds an electron trajectory from the electron emission source 36a toward the anode target 35. The focusing electrode 36b focuses the electron beam and shapes (optimizes) the electron beam (electron distribution shape).

  A negative high voltage with respect to the anode target 35 is applied to the cathode 36 (electron emission source 36a). As described above, a voltage of, for example, 10 kV or less is applied to the focusing electrode 36b as a voltage for shaping the electron beam. More preferably, the voltage value applied to the focusing electrode 36b can be changed. If the voltage value can be changed in this way, the shape of the electron beam can be changed and the size of the focal point F described later can be adjusted.

  The reflective electrode 136 is installed between the X-ray emission window 33 and the anode target 35. The window 136a is installed in parallel to the X-ray radiation window 33, for example. The window 136 a is installed so that X-rays radiated from the focal point F of the target surface 35 b are transmitted to the X-ray emission window 33. For example, the window 136 a is formed with a width larger than that of the X-ray emission window 33. The reflective electrode 136 can push back (reflect) recoiled electrons by the action of an electric field generated in the surroundings. For example, the reflective magnetic pole 136 reflects the electrons rebounded in the direction of the reflective electrode 136 by the electric field generated around the target surface 35b. At this time, the arrangement or the like of the reflective electrode 136 may be adjusted so that the reflective electrode 136 reflects the recoil electrons away from the focal point F or at a portion other than the focal point.

  The high voltage connector 300 includes a housing 301, a cable 302, a fixing portion 303, and a silicone plate 304 that constitutes the outer end surface portion 48. The high voltage connector 300 supplies a high voltage to the voltage supply terminal 44. The distal end portion including the terminal 302 a of the cable 302 is inserted into the housing 301. The fixing portion 303 is provided in close contact with the silicone plate 304 as the outer end surface portion 48 so as to press the outer end surface portion 48. The fixing unit 303 fixes the terminal 302a toward the voltage supply terminal 44 side. The fixing part 303 is an insulating member. The fixing portion 303 is formed of, for example, an epoxy resin member. The silicone plate 304 is provided between the bottom portion 47 and the fixing portion 303. The silicone plate 304 is formed of a silicone resin member.

  In the present embodiment, a negative high voltage is applied to the cathode 36 from the high voltage power supply 15A, and a positive high voltage is applied to the anode target 35 from the high voltage power supply 15B. At this time, a negative high voltage equivalent to that of the cathode 36 is applied to the reflective electrode 136 connected to the cathode 36. An electron beam is emitted from the electron emission source 36a of the cathode 36 toward the target surface 35b of the anode target 35 in the first direction d1. The electron beam is shaped by the focusing electrode 36b and enters the focal point F. X-rays are emitted from the focal point F toward the second direction d2 by the electron beam incident on the focal point F of the target surface 35b. X-rays pass through the window 136a, pass through the X-ray emission window 33, and are emitted to the outside. Here, a part of the electron beam is scattered in the second direction d2 as recoil electrons in the same manner as the X-ray. Recoil electrons scattered in the second direction are reflected by the action of an electric field generated in the vicinity of the reflective electrode 136 having substantially the same potential as the cathode 36. Further, as shown in FIGS. 1 and 2, the reflected recoil electrons strike the anode target 35 away from the focal point F.

  In the present embodiment, the reflective electrode 136 is connected to the cathode 36, has the same potential as the cathode 36, and is disposed between the X-ray emission window portion 33 and the anode target 35. When electrons emitted from the electron emission source 36 a bombard the focal point F on the anode target 35 to generate X-rays, the electrons recoiled at the focal point F are pushed back onto the anode target 35 by the reflective electrode 136. It is. That is, recoil electrons are prevented from recoiling toward the X-ray emission window 33. As a result, heating of the X-ray emission window 33 due to impact of recoil electrons is reduced.

  Further, by reducing the heating of the X-ray radiation window portion 33, the X-ray radiation window portion 33 is formed of an inexpensive member such as aluminum, titanium, nickel, stainless steel, chromium steel, iron alloy other than expensive beryllium. Even so, the X-ray radiation window portion 33 formed of these inexpensive members has sufficient resistance as an X-ray radiation window. That is, the manufacturing cost of the X-ray tube apparatus 10 can be reduced.

  A modification of the present embodiment will be described below with reference to the drawings. Since the X-ray tube apparatus according to the modification has substantially the same configuration as the X-ray tube apparatus according to the first embodiment, the same reference numerals are assigned to the same components as those of the X-ray tube apparatus according to the first embodiment. A detailed description thereof will be omitted.

FIG. 5 is a schematic diagram of an X-ray tube apparatus 10 according to a modification of the first embodiment.
As shown in FIG. 5, the modified X-ray tube 30 is an anode ground tube. Therefore, the X-ray tube apparatus 10 has the high voltage power supply 15A on the cathode 36 side, and the anode target 35 is grounded.

  The high voltage power supply 15 </ b> A supplies a high voltage between the anode target 35 and the cathode 36. In the modification, the high voltage power supply 15A is applied with a negative high voltage to the cathode 36 and a voltage of −V. The anode target 35 and the vacuum envelope 31 (the inner surface portion 34 thereof) are grounded (set to the ground potential).

  In the modified example, the negative voltage is applied to the cathode 36 from the high voltage power supply 15A. At this time, a negative high voltage equivalent to that of the cathode 36 is applied to the reflective electrode 136 connected to the cathode 36. An electron beam is emitted from the electron emission source 36a of the cathode 36 toward the target surface 35b of the anode target 35 (in the first direction d1). The electron beam is shaped by the focusing electrode 36b and enters the focal point F. X-rays are emitted from the focal point F toward the second direction d2 by the electron beam incident on the focal point F of the target surface 35b. X-rays pass through the window 136a, pass through the X-ray emission window 33, and are emitted to the outside. Here, a part of the electron beam is scattered in the second direction d2 as recoil electrons in the same manner as the X-ray. Recoil electrons scattered in the second direction are reflected by the action of an electric field generated in the vicinity of the reflective electrode 136 having substantially the same potential as the cathode 36. The reflected recoil electrons strike the anode target 35 away from the focal point F.

  In a modification, the X-ray tube 30 is an anode ground tube. Even if the X-ray tube 30 is an anode ground tube, recoil electrons are prevented from recoiling in the direction of the X-ray emission window 33 as in the first embodiment. As a result, heating of the X-ray emission window 33 due to impact of recoil electrons is reduced.

  Next, an X-ray tube apparatus according to another embodiment will be described. In other embodiments, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

(Second Embodiment)
FIG. 6 is a schematic diagram showing the principle of generation of X-rays in the X-ray tube apparatus according to the second embodiment, and shows the arrangement of components in a plane orthogonal to the target surface. FIG. 7 is a cross-sectional view of the X-ray tube apparatus taken along line VII-VII in FIG. 6, and the front configuration of the X-ray tube apparatus is shown in FIG.

  First, the basic operation principle of the X-ray tube apparatus 10 of the second embodiment will be described with reference to FIGS. 6 and 7. The X-ray tube apparatus 10 according to the present embodiment further includes a first magnetic deflection unit (first magnetic unit) 110 and a deflection power source 115.

  Although details will be described later, in the present embodiment, a first magnetic deflection unit 110 is provided to deflect the trajectory of recoil electrons. As shown in FIG. 6, the first magnetic deflection unit 110 is composed of two opposing magnetic pole members. Each of these two opposing magnetic pole members is formed of a flat plate, for example. The first magnetic deflection unit 110 composed of these two flat plates facing each other is sandwiched between the anode target 35 and the X-ray emission window 33 outside the X-ray tube 30 (vacuum envelope 31). is set up. The two opposing magnetic pole members of the first magnetic deflection unit 110 generate a magnetic field Ha inside the vacuum envelope 31 having the inner surface portion 34. As shown in FIG. 6, for example, the magnetic field Ha is generated in a direction in which the direction of the magnetic field is parallel to the first direction d1 of the X-ray apparatus. In the present embodiment, the magnetic field Ha is generated so that the direction of the magnetic field is from the anode target 35 side to the cathode 36 side. As shown in FIG. 7, the trajectory of recoil electrons is deflected by the magnetic field Ha.

  Hereinafter, the detailed structure of the X-ray tube apparatus 10 according to the present embodiment will be described with reference to FIGS. 8, 9, and 10.

  FIG. 8 is a sectional view showing a detailed structure of the X-ray tube apparatus. FIG. 9 is a cross-sectional view of the X-ray tube apparatus taken along line IX-IX in FIG. 8, and shows a front outline of the X-ray tube apparatus 10. FIG. 10 is a perspective view showing an external configuration including the X-ray tube 30 and the first magnetic deflection unit 110 in the X-ray tube apparatus 10 of the present embodiment.

  The first magnetic deflection unit 110 has two magnetic poles (not shown), a yoke 112 connected to the magnetic poles, and a coil 113 wound around the yoke 112. In the present embodiment, the first magnetic deflection unit 110 uses an electromagnet, but is not limited to this, and may use a permanent magnet. The first magnetic deflection unit 110 generates a magnetic field Ha and deflects the electron beam using Lorentz force. The first magnetic deflection unit 110 generates the magnetic field Ha in at least a part of the space between the X-ray radiation window unit 33 and the focal point F. The magnetic field Ha continuously changes the trajectory of recoil electrons. The first magnetic deflection unit 110 may be able to adjust the strength (magnetic flux density) of the magnetic field Ha.

  As shown in FIG. 10, in the first magnetic deflection unit 110, a pair of yokes 112 are connected to each other so as to form a U-shape. The pair of yokes 112 are connected so as to cover the vacuum envelope 31, for example. The first magnetic deflection unit 110 is disposed so that a part of the X-ray tube 30 is accommodated between the magnetic poles that are opposed ends of the pair of yokes 112. More specifically, the first magnetic deflection unit 110 is installed outside the vacuum envelope 31 so that the magnetic poles of the pair of yokes 112 sandwich the vacuum envelope 31. The magnetic poles of these yokes 112 are formed in a flat plate shape, for example. Here, the magnetic poles of the pair of yokes 112 have a width extending between the focal point F and the X-ray emission window portion 33.

  The deflection power source 115 is electrically connected to the first magnetic deflection unit 110 and supplies a current to the coil 113. The first magnetic deflection unit 110 and the deflection power source 115 form a deflection magnetic field generation unit.

  In the present embodiment, a negative high voltage is applied to the cathode 36 from the high voltage power supply 15A, and a positive high voltage is applied to the anode target 35 from the high voltage power supply 15B. At this time, a negative high voltage equivalent to that of the cathode 36 is applied to the reflecting magnetic pole 136 connected to the cathode 36. An electron beam is emitted from the electron emission source 36a of the cathode 36 toward the target surface 35b of the anode target 35 in the first direction d1. The electron beam is shaped by the focusing electrode 36b and enters the focal point F. X-rays are emitted from the focal point F toward the second direction d2 by the electron beam incident on the focal point F of the target surface 35b. X-rays pass through the window 136a, pass through the X-ray emission window 33, and are emitted to the outside. Here, a part of the electron beam is scattered in the second direction d2 as recoil electrons in the same manner as the X-ray. Recoil electrons scattered in the second direction are reflected by the action of an electric field generated in the vicinity of the reflective electrode 136 having substantially the same potential as the cathode 36. Further, as shown in FIGS. 6 and 7, the reflected recoil electrons bombard on the anode target 35 away from the focal point F in order to keep the trajectory deflected in one direction by the magnetic field Ha. In addition, for example, the first magnetic field is emitted so that many recoil electrons are scattered and incident on the anode target 35 outside the projection range determined by projecting the X-ray radiation window 33 onto the anode target 35. The magnitude of the magnetic field Ha generated by the deflecting unit 110 may be set.

  In the present embodiment, the first magnetic deflection unit 110 generates a magnetic field Ha. The magnetic field Ha continues to further deflect the trajectory of recoil electrons reflected by the action of the electric field generated in the vicinity of the reflective electrode 136. Recoil electrons strike the anode target 35 away from the focal point F. As a result, the temperature rise at the focal point F is reduced. Further, since recoil electrons impact on the anode target 35 away from the focal point F, generation of X-rays near the focal point F due to recoil electrons is reduced. As a result, X-rays generated by recoil electrons are reduced from being mixed into the used X-rays.

  A modification of the present embodiment will be described below with reference to the drawings. Since the X-ray tube apparatus according to the modification has substantially the same configuration as the X-ray tube apparatus according to the second embodiment, the same reference numerals are assigned to the same components as those of the X-ray tube apparatus according to the second embodiment. A detailed description thereof will be omitted.

FIG. 11 is a schematic diagram of an X-ray tube apparatus 10 according to a modification of the second embodiment.
As shown in FIG. 11, the modified X-ray tube 30 is an anode ground tube. Therefore, the X-ray tube apparatus 10 has the high voltage power supply 15A on the cathode 36 side, and the anode target 35 is grounded.

  The high voltage power supply 15 </ b> A supplies a high voltage between the anode target 35 and the cathode 36. In the modification, the high voltage power supply 15A is applied with a negative high voltage to the cathode 36 and a voltage of −V. The anode target 35 and the vacuum envelope 31 (the inner surface portion 34 thereof) are grounded (set to the ground potential).

  In the modified example, the negative voltage is applied to the cathode 36 from the high voltage power supply 15A. At this time, a negative high voltage equivalent to that of the cathode 36 is applied to the reflective electrode 136 connected to the cathode 36. An electron beam is emitted from the electron emission source 36a of the cathode 36 toward the target surface 35b of the anode target 35 in the first direction d1. The electron beam is shaped by the focusing electrode 36b and enters the focal point F. X-rays are emitted from the focal point F toward the second direction d2 by the electron beam incident on the focal point F of the target surface 35b. X-rays pass through the window 136a, pass through the X-ray emission window 33, and are emitted to the outside. Here, a part of the electron beam is scattered in the second direction d2 as recoil electrons in the same manner as the X-ray. Recoil electrons scattered in the second direction are reflected by the action of an electric field generated in the vicinity of the reflective electrode 136 having substantially the same potential as the cathode 36. Further, as shown in FIGS. 6 and 7, the reflected recoil electrons bombard on the anode target 35 away from the focal point F in order to keep the trajectory deflected in one direction by the magnetic field Ha. In addition, for example, the first magnetic field is emitted so that many recoil electrons are scattered and incident on the anode target 35 outside the projection range determined by projecting the X-ray radiation window 33 onto the anode target 35. The magnitude of the magnetic field Ha generated by the deflecting unit 110 may be set.

  In a modification, the X-ray tube 30 is an anode ground tube. Even if the X-ray tube 30 is an anode ground tube, the temperature rise of the focal point F is reduced as in the second embodiment. Further, since recoil electrons impact on the anode target 35 away from the focal point F, generation of X-rays near the focal point F due to recoil electrons is reduced. As a result, the mixing of X-rays generated by recoil electrons into the utilization X-rays is also reduced.

(Third embodiment)
The third embodiment will be described below. The X-ray tube apparatus according to the third embodiment is further provided with a magnetic deflection unit.

  FIG. 12 is a schematic diagram showing the principle of the X-ray tube apparatus according to the second embodiment, as viewed from the direction along the target surface. FIG. 13 is a cross-sectional view of the X-ray tube device taken along line XIII-XIII in FIG. 12, and includes a part of the front view of the X-ray tube device.

  In addition to the configuration of the X-ray tube device of the first embodiment, the X-ray tube device 10 of the third embodiment includes a second magnetic deflection unit (second magnetic unit) 120 and a deflection power source 125. It has more.

  The second magnetic deflection unit 120 generates a magnetic field Hb. The trajectory of the electron beam incident on the anode target 35 is deflected by the magnetic field Hb. As shown in FIG. 13, the magnetic field Hb is a direction (third direction d3) perpendicular to a plane (first plane S1) spreading in two directions, a first direction d1 and a second direction d2. Has been generated. The direction of the magnetic field Hb is, for example, generated in a 90 ° direction clockwise from the second direction in the second direction d2 and the third direction d3 and a plane extending in two directions (second plane S2). .

  In this embodiment, the trajectory of the incident electron beam is deflected by the magnetic field Hb generated by the second magnetic deflection unit 120. Since the electron beam continues to be affected by the magnetic field Hb, the traveling direction of the electron beam continuously changes from the first direction d1 to the bending direction d12. At this time, the electron beam is incident on the target surface 35b at a shallow angle. When the uniform magnetic field and the uniform electric field are simplified to be orthogonal, the trajectory of the electron beam becomes a cycloid curve. Therefore, as shown in FIG. 6, the bending direction d12 is a trajectory like a cycloid curve. Thus, by making the light incident on the target surface 35b of the anode target 35 at a relatively shallow angle, the output of X-rays emitted from the target surface 35b increases. The incident angle α of the electron beam on the target surface 35b (the angle between the target surface 35b and the bending direction d12) can be set to a target angle (orientation) by adjusting the magnitude of the magnetic field Hb. .

  The electron beam is subjected to the action of a magnetic field Hb generated by the second magnetic deflection unit 120 in parallel to the target surface 35b and perpendicular to the first plane. The magnetic field Hb is generated over the entire space between the cathode 36 and the target surface (surface) 35 b of the anode target 35. With these magnetic fields Hb, an electron beam can be incident on the target surface 35b from the bending direction d12. The magnetic field Hb is set according to the magnitude of the tube voltage.

  The X-ray output emitted from the X-ray emission window 33 can be increased by making the electron beam incident on the target surface 35b at such a shallow angle α. Here, the angle α is defined as an angle formed by the electron beam with respect to the target surface 35b as shown in FIG.

  The effect as described above can be obtained when the angle α is in the range of 0 ° to 40 ° (0 ° <α ≦ 40 °). Furthermore, in order to further enhance these effects, it is more preferable that the angle is in a range greater than the angle α5 ° and 30 ° or less (5 ° <α ≦ 30 °). A part of the electron beam incident on the target surface 35b is scattered in the second direction d2 as recoil electrons.

  Hereinafter, the detailed structure of the X-ray tube apparatus 10 according to the second embodiment will be described with reference to FIGS. 14 and 15.

  FIG. 14 is a cross-sectional view of the X-ray tube apparatus of the present embodiment taken along line IV-IV of FIG. 3 in the present embodiment, and includes a part of the front view of the X-ray tube apparatus. FIG. 15 is a perspective view schematically showing the external appearance of the X-ray tube and the second magnetic deflection unit in the X-ray tube apparatus shown in FIG.

  In the present embodiment, a partial cross-sectional view of the X-ray tube apparatus 10 is equivalent to FIG. As shown in FIG. 14, in the X-ray tube device 10, the second magnetic deflection unit 120 is installed inside the housing 20 and outside the vacuum envelope 31.

  As shown in FIGS. 14 and 15, the second magnetic deflection unit 120 includes two magnetic poles 121, a yoke 122 connected to the magnetic poles, and a coil 123 wound around the yoke 122. In the present embodiment, the second magnetic deflection unit 120 uses an electromagnet, but is not limited to this, and may use a permanent magnet. The second magnetic deflection unit 120 generates a magnetic field Hb so as to cross the trajectory of the electron beam from the cathode 36 toward the target surface 35b, and deflects the electron beam using Lorentz force. The second magnetic deflection unit 120 generates the magnetic field Hb over the entire space between the cathode 36 and the target surface 35b. The magnetic field Hb continuously changes the trajectory of the incident electrons. The second magnetic deflection unit 120 may be able to adjust the strength (magnetic flux density) of the magnetic field Hb.

  As shown in FIG. 15, in the second magnetic deflection unit 120, a pair of yokes 122 are formed to have a U-shape. In the second magnetic deflection unit 120, the X-ray tube 30 is disposed between the end surfaces of the pair of yokes 122. Further, in the second magnetic deflecting unit 120, two yokes 122 positioned outside the vacuum envelope 31 are installed so as to face each other with the vacuum envelope 31 interposed therebetween. These yokes 122 are formed so as to have, for example, a plate-shaped end surface. As shown in FIGS. 14 and 15, the pair of yokes 122 are coupled so as to have a size that covers the target surface 35 b, for example. Here, the end surfaces of the plurality of yokes 122 have a depth width extending between the cathode 36 and the focal point F, for example.

  The deflection power source 125 is electrically connected to the second magnetic deflection unit 120 and supplies a current to the coil 123. The second magnetic deflection unit 120 and the deflection power source 125 form a deflection magnetic field generation unit.

  In the present embodiment, a negative high voltage is applied to the cathode 36 from the high voltage power supply 15A, and a positive high voltage is applied to the anode target 35 from the high voltage power supply 15B. At this time, a negative high voltage equivalent to that of the cathode 36 is applied to the reflective electrode 136 connected to the cathode 36. An electron beam is emitted from the electron emission source 36a of the cathode 36 toward the target surface 35b of the anode target 35 in the first direction d1. The electron beam is shaped by the focusing electrode 36b and enters the focal point F. By the magnetic field Hb generated by the second magnetic deflection unit 120, the electron beam is continuously deflected and bent in the bending direction d12. The electron beam is incident on the focal point F in a trajectory like a cycloid curve. X-rays are emitted from the focal point F toward the second direction d2 by the electron beam incident on the focal point F of the target surface 35b. X-rays pass through the window 136a, pass through the X-ray emission window 33, and are emitted to the outside. Here, a part of the electron beam is scattered in the second direction d2 as recoil electrons in the same manner as the X-ray. Recoil electrons scattered in the second direction are reflected by the action of an electric field generated in the vicinity of the reflective electrode 136 having substantially the same potential as the cathode 36. Further, as shown in FIGS. 12 and 13, the reflected recoil electrons impact on the anode target 35 away from the focal point F.

  In the present embodiment, the electron beam emitted from the cathode 36 is incident on the target surface 35b at a shallow angle α by the action of the magnetic field Hb generated by the second magnetic deflection unit 120. Since the focal point F is formed by making the electron beam incident on the target surface at a relatively shallow angle, the X-ray output emitted from the X-ray emission window 33 can be increased. The smaller the angle α, the greater the X-ray output.

  A modification of the present embodiment will be described below with reference to the drawings. Since the X-ray tube apparatus according to the modification has substantially the same configuration as the X-ray tube apparatus according to the third embodiment, the same reference numerals are given to the same components as those of the X-ray tube apparatus according to the third embodiment. A detailed description thereof will be omitted.

FIG. 16 is a schematic diagram of an X-ray tube apparatus 10 according to a modification of the third embodiment.
As shown in FIG. 16, a modified X-ray tube 30 is an anode ground tube. Therefore, the X-ray tube apparatus 10 has the high voltage power supply 15A on the cathode 36 side, and the anode target 35 is grounded.

  The high voltage power supply 15 </ b> A supplies a high voltage between the anode target 35 and the cathode 36. In the modification, the high voltage power supply 15A is applied with a negative high voltage to the cathode 36 and a voltage of −V. The anode target 35 and the vacuum envelope 31 (the inner surface portion 34 thereof) are grounded (set to the ground potential).

  In the modified example, the negative voltage is applied to the cathode 36 from the high voltage power supply 15A. At this time, a negative high voltage equivalent to that of the cathode 36 is applied to the reflective electrode 136 connected to the cathode 36. An electron beam is emitted from the electron emission source 36a of the cathode 36 toward the target surface 35b of the anode target 35 in the first direction d1. The electron beam is shaped by the focusing electrode 36b and enters the focal point F. By the magnetic field Hb generated by the second magnetic deflection unit 120, the electron beam is continuously deflected and bent in the bending direction d12. The electron beam is incident on the focal point F in a trajectory like a cycloid curve. X-rays are emitted from the focal point F toward the second direction d2 by the electron beam incident on the focal point F of the target surface 35b. X-rays pass through the window 136a, pass through the X-ray emission window 33, and are emitted to the outside. Here, a part of the electron beam is scattered in the second direction d2 as recoil electrons in the same manner as the X-ray. Recoil electrons scattered in the second direction are reflected by the action of an electric field generated in the vicinity of the reflective electrode 136 having substantially the same potential as the cathode 36. Further, the reflected recoil electrons impact on the anode target 35 away from the focal point F.

In a modification, the X-ray tube 30 is an anode ground tube. Even if the X-ray tube 30 is an anode grounded tube, the focal point F is formed by making the electron beam incident at a relatively shallow angle with respect to the target surface as in the third embodiment. The X-ray output emitted from the window 33 can be increased. The smaller the angle α, the greater the X-ray output.

  Next, an X-ray tube apparatus according to another embodiment will be described. In other embodiments, the same parts as those in the third embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

(Fourth embodiment)
The fourth embodiment will be described below. The X-ray tube apparatus according to the fourth embodiment is different from the X-ray tube apparatus according to the third embodiment in that a first magnetic deflection unit 110 is further provided.

  FIG. 17 is a schematic diagram illustrating the principle of the X-ray tube apparatus according to the second embodiment, as viewed from the direction along the target surface. FIG. 18 is a cross-sectional view of the X-ray tube apparatus taken along line XVIII-XVIII in FIG. 17 and includes a part of the front view of the X-ray tube apparatus. FIG. 19 is a perspective view showing a part including the magnetic deflection unit in the X-ray tube apparatus of the present embodiment.

  As shown in FIGS. 17, 18, and 19, the X-ray tube apparatus 10 of the fourth embodiment includes a first magnetic deflection unit in addition to the configuration of the X-ray tube apparatus 10 of the third embodiment. (First magnetic part) 110 and a deflection power source 115 are further provided.

  In the present embodiment, a negative high voltage is applied to the cathode 36 from the high voltage power supply 15A, and a positive high voltage is applied to the anode target 35 from the high voltage power supply 15B. At this time, a negative high voltage equivalent to that of the cathode 36 is applied to the reflective electrode 136 connected to the cathode 36. An electron beam is emitted from the electron emission source 36a of the cathode 36 toward the target surface 35b of the anode target 35 in the first direction d1. The electron beam is shaped by the focusing electrode 36b and enters the focal point F. By the magnetic field Hb generated by the second magnetic deflection unit 120, the electron beam is continuously deflected and bent in the bending direction d12. The electron beam is incident on the focal point F in a trajectory like a cycloid curve. X-rays are emitted from the focal point F toward the second direction d2 by the electron beam incident on the focal point F of the target surface 35b. X-rays pass through the window 136a, pass through the X-ray emission window 33, and are emitted to the outside. Here, a part of the electron beam is scattered in the second direction d2 as recoil electrons in the same manner as the X-ray. Recoil electrons scattered in the second direction are reflected by the action of an electric field generated in the vicinity of the reflective electrode 136 having substantially the same potential as the cathode 36. Further, as shown in FIGS. 1 and 2, the reflected recoil electrons bombard the anode target 35 away from the focal point F in order to keep the trajectory deflected in one direction by the magnetic field Ha. In addition, for example, the magnitude of the magnetic field Ha generated by the first magnetic deflection unit 101 so that many recoil electrons are scattered outside the projection range determined by the X-ray emission window 33 being projected onto the anode target 35. May be set.

  In the present embodiment, the first magnetic deflection unit 110 generates a magnetic field Ha. The magnetic field Ha continues to further deflect the recoil electron trajectory reflected by the action of the electric field generated in the vicinity of the reflective magnetic pole 136. Recoil electrons strike the anode target 35 away from the focal point F. As a result, the temperature rise at the focal point F is reduced. Further, since recoil electrons impact on the anode target 35 away from the focal point F, generation of X-rays near the focal point F due to recoil electrons is reduced. As a result, X-rays generated by recoil electrons are reduced from being mixed into the used X-rays. Further, due to the action of the magnetic field Hb generated by the second magnetic deflection unit 120, the electron beam emitted from the cathode 36 enters the target surface 35b at a shallow angle α. Since the focal point F is formed by making the electron beam incident on the target surface at a relatively shallow angle, the X-ray output emitted from the X-ray emission window 33 can be increased. The smaller the angle α, the greater the X-ray output.

  In the above-described embodiment, the reflective electrode 136 is connected to the cathode 36 at one end. However, the window 136a is at the same potential as the cathode 36, and the focal point F and the X-ray emission window 33 are located between them. As long as it is installed. For example, a configuration in which a voltage is directly applied to the window 136a from a high-voltage power supply equivalent to the cathode 36 may be employed. Further, the reflective electrode 136 may be formed integrally with the cathode 36 or may be connected as a separate body. The window 136a may also be formed integrally with the reflective electrode 136 or may be connected as a separate body.

  In addition, this invention is not limited to the said embodiment itself, In the stage of implementation, it can implement by modifying a component in the range which does not deviate from the summary. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  DESCRIPTION OF SYMBOLS 10 ... X-ray tube apparatus, 15 ... High voltage power supply, 30 ... X-ray tube, 31 ... Vacuum envelope, 32 ... Vacuum container, 32a ... Side wall, 33 ... X-ray emission window part, 34 ... Inner surface part, 35 Anode target, 35a ... target layer, 35b ... target surface, 35d ... recoil electron capture surface, 36 ... cathode, 36a ... electron emission source, 36b ... focusing electrode (focusing cup), 110 ... first magnetic deflection unit, 112, 122 ... yoke, 113, 123 ... coil, 115, 125 ... deflection power supply, 120 ... second magnetic deflection unit, 121 ... magnetic pole, 136 ... reflection electrode, 136a ... window.

Claims (11)

A cathode with an emission source to which a negative high voltage is applied and emits an electron beam;
An anode target having a target surface on which a positive high voltage is applied to the cathode and is disposed opposite to the cathode and on which a focal point for emitting X-rays is formed when the electron beam is incident;
A vacuum envelope that houses the cathode and the anode target in a vacuum-tight manner;
A radiation window portion that is formed on a part of the wall surface of the vacuum envelope having a higher potential than the cathode, and allows radiation of X-rays emitted from the anode target to the outside;
An X-ray tube apparatus comprising an electrode member that has the same potential as the cathode, is disposed between the focal point and the radiation window, and reflects a part of recoil electrons reflected from the focal point.   The electrode member is formed in a conductive long shape, one end portion is connected to the cathode, and a tip portion opposite to the one end portion is disposed between the focal point and the radiation window portion. The X-ray tube apparatus according to claim 1.   The electrode member spreads in a direction perpendicular to a plane along the focal point and the center of the radiation window portion in order to reflect the recoil electrons, and reflects the reflection member having the same potential as the cathode to the tip portion. The X-ray tube apparatus of Claim 2 with which it comprises.   The X-ray tube apparatus according to claim 3, wherein the reflection member includes a window portion that is disposed on a straight line connecting the focal point and the center of the radiation window portion and transmits X-rays emitted from the focal point.   The X-ray tube apparatus of Claim 4 provided with the 1st magnetic part which produces | generates a magnetic field between the said focus and the said radiation | emission window part.   The X-ray tube apparatus according to claim 5, wherein the first magnetic unit generates a magnetic field in a direction perpendicular to a plane along the focal point and the center of the radiation window unit.   The X-ray tube apparatus according to claim 6, wherein the first magnetic unit generates a magnetic field along a direction from the anode target toward the cathode. The vacuum envelope has a surface portion that is a wall surface portion on which the radiation window portion is formed,
The X-ray tube apparatus according to claim 7, wherein the surface portion is maintained at the same potential as the cathode.   The X-ray tube apparatus according to claim 8, further comprising: a second magnetic unit that generates a magnetic field between the cathode and the anode target.   The X-ray tube apparatus according to claim 9, wherein the second magnetic unit generates a magnetic field in a direction perpendicular to a plane along the center of the emission source of the electron beam emitted from the cathode and the focal point.   When the electron beam emitted from the cathode is bent by the magnetic field generated by the second magnetic unit and enters the anode target, the incident angle of the electron beam is 1 from the surface of the anode target. The X-ray tube apparatus according to claim 10, wherein the second magnetic unit is set to have any angle within a range of greater than 40 ° and less than 40 °.

Images