JP2013037910A - X-ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray tube device capable of reliably reducing temperature rise on an X-ray transmission window and reducing X-rays going toward the X-ray transmission window from an area other than a focal point, by suppressing direct hits of recoil electrons to the X-ray transmission window.SOLUTION: An X-ray tube device includes an X-ray tube and a deflection unit. The X-ray tube includes: a cathode for emitting electron beams in a first direction d1; an anode target 35 having a target surface 35b where a focal point F is formed for emitting X-ray beams to be used with a second direction d2 as a central axis; a vacuum envelope having an X-ray transmission window for taking the X-ray beams to be used to the outside; and an X-ray shield member 5. The X-ray shield member 5 includes a passage unit for making the electron beams and the X-ray beams to be used pass through it, and shields X-rays going toward the X-ray transmission window from an area other than the focal point F. The deflection unit deflects the electron beams to be incident on the target surface 35b in a third direction d3.

Description

  Embodiments described herein relate generally to an X-ray tube apparatus.

  The X-ray tube apparatus includes an X-ray tube. The X-ray tube is configured to generate an X-ray by colliding an electron beam with an anode target. Such an X-ray tube apparatus is used in many applications such as a medical diagnostic apparatus, an industrial nondestructive inspection apparatus, and a material analysis apparatus.

  In an 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, and typically has an energy of 20 to 150 keV and is substantially perpendicular to the target surface of the anode target. A focal point that forms an X-ray generation source by colliding with (90 ° ± 20 °) is formed. When an electron beam with high energy collides with the focal point, the electron beam is rapidly decelerated by the target material, so that X-rays are emitted. The rate of conversion to X-rays is as small as 1% or less of the kinetic energy of electrons that collide with the anode target. The remaining energy is converted to heat.

JP 2002-216683 A

  By the way, the recoil electrons jump out of the focal point over a wide angle range from the target surface. Therefore, recoil electrons that jump out in the direction of the X-ray transmission window directly hit the X-ray transmission window and heat the X-ray transmission window. As a result, the degree of vacuum in the X-ray tube decreases and discharge occurs. Or the X-ray transmission window may be damaged. The temperature rise of the X-ray transmission window is particularly serious when the X-ray transmission window is at the same potential as the anode target.

  Then, due to the heating of the X-ray transmission window described above, the electron beam output is increased to increase the X-ray output, the X-rays are emitted more frequently, or the X-ray is emitted for a longer time. There is a problem that there is a limit to the continuous emission of the line. Furthermore, heating of the X-ray transmission window is performed by bringing lead, which is an X-ray shielding material dissolved in the coolant, and heavy metal such as copper, which is the material of the X-ray tube and the cooling pipe, to the outside of the X-ray transmission window. There is also a problem that the phenomenon of deposition is accelerated and the X-ray transmission characteristics of the X-ray transmission window are impaired in a short period of time.

  Further, a part of the recoil electrons jumping out from the focal point of the target surface returns to the target surface again, and a relatively high-density collision region is formed around the focal point. X-rays are also emitted from the collision area. For this reason, undesired X-rays (out-of-focus X-rays) emitted from the collision area are mixed into the utilization X-ray bundle emitted from the focal point.

  Furthermore, when the X-rays emitted from the focal point deviate from the X-ray transmission window, they are scattered on the inner surface of the cathode and the vacuum envelope. For this reason, part of the scattered unwanted X-rays (out-of-focus X-rays, scattered X-rays) is also mixed into the used X-ray bundle emitted from the focal point. As described above, when the X-rays go from other than the focal point to the X-ray transmission window, the resolution of the X-ray image is also deteriorated.

  The present invention has been made in view of the above points, and its object is to suppress recoil electrons directly hitting the X-ray transmission window, and to reliably reduce the temperature rise of the X-ray transmission window. An object of the present invention is to provide an X-ray tube apparatus capable of reducing X-rays directed from an X-ray to an X-ray transmission window.

An X-ray tube apparatus according to one embodiment
A target that forms a cathode that emits an electron beam in a first direction, and a focal point that emits a utilization X-ray bundle having a second direction different from the first direction as a central axis when the electron beam is incident. An anode target having a surface, a vacuum envelope containing the anode target and the cathode, the inside of which is in a vacuum state, and having an X-ray transmission window for taking out the used X-ray bundle to the outside; An X-ray that is located between the focal point and the X-ray transmission window in the envelope and has a passing part that allows the electron beam and the X-ray beam to pass therethrough, and shields X-rays from other than the focal point toward the X-ray transmission window. An X-ray tube comprising a shield member;
And a deflecting unit that deflects the electron beam emitted from the cathode and causes the electron beam to enter the target surface in a third direction different from the first direction.

FIG. 1 is a schematic diagram showing the X-ray apparatus according to the first embodiment, as viewed from a direction perpendicular to the target surface. FIG. 2 is another schematic diagram showing the X-ray apparatus shown in FIG. 1 and is a view seen from a direction along the target surface. FIG. 3 is a perspective view showing the anode target and the X-ray shield member shown in FIGS. 1 and 2, and shows a state where a focal point is formed by deflecting an electron beam. FIG. 4 is a perspective view showing an anode target and an X-ray shield member of the X-ray apparatus according to the second embodiment, and shows a state where a focal point is formed by deflecting an electron beam. FIG. 5 is a perspective view showing an anode target and an X-ray shield member of an X-ray apparatus according to the third embodiment, and shows a state where a focal point is formed by deflecting an electron beam. FIG. 6 is a perspective view showing an anode target and an X-ray shield member of an X-ray apparatus according to the fourth embodiment, and shows a state where a focal point is formed by deflecting an electron beam. FIG. 7 is a perspective view showing an anode target and an X-ray shield member of the X-ray apparatus according to the fifth embodiment, and shows a state in which a focal point is formed by deflecting an electron beam. FIG. 8 is a perspective view showing an anode target and an X-ray shield member of an X-ray apparatus according to the sixth embodiment, and shows a state where a focal point is formed by deflecting an electron beam. FIG. 9 is a schematic diagram showing a modification of the X-ray apparatus according to the first embodiment, and shows how the positions of the cathode and the X-ray shield member are changed and the direction of the third direction is changed. It is. FIG. 10 is another schematic diagram illustrating the X-ray apparatus illustrated in FIG. 9 and is a diagram viewed from a direction along the target surface. FIG. 11 is a schematic diagram showing another modification of the X-ray apparatus according to the first embodiment, as viewed from the direction along the target surface. FIG. 12 is a perspective view showing the anode target and the X-ray shield member shown in FIG. 11, and shows how the focal point moves on the target surface by deflecting the electron beam. FIG. 13 is a cross-sectional view showing an X-ray tube apparatus of an X-ray apparatus according to the seventh embodiment. FIG. 14 is a cross-sectional view showing the X-ray tube device taken along line XIV-XIV in FIG. FIG. 15 is a cross-sectional view showing an X-ray tube apparatus of an X-ray apparatus according to the eighth embodiment. FIG. 16 is a cross-sectional view showing an X-ray tube apparatus of an X-ray apparatus according to the ninth embodiment. FIG. 17 is a cross-sectional view showing the X-ray tube device taken along line XVII-XVII in FIG. FIG. 18 is a front view schematically showing a modification of the X-ray shield member. FIG. 19 is a front view schematically showing another modification of the X-ray shield member. FIG. 20 is a front view schematically showing another modification of the X-ray shield member. FIG. 21 is a front view schematically showing another modification of the X-ray shield member. FIG. 22 is a front view schematically showing another modified example of the X-ray shield member. FIG. 23 is a cross-sectional view schematically showing another modification of the X-ray shield member.

Hereinafter, the X-ray apparatus according to the first embodiment will be described in detail with reference to the drawings. In the first embodiment, a basic concept of an X-ray apparatus will be described.
As shown in FIGS. 1, 2, and 3, the X-ray apparatus includes an X-ray tube apparatus 10. The X-ray tube device 10 includes an X-ray tube 30 and a deflection unit 70. The X-ray tube 30 includes an anode target 35, a cathode 36, a vacuum envelope 31, and an X-ray shield member 5.

  The cathode 36 emits an electron beam in the first direction d1. A voltage and current applied to the cathode 36 are supplied to the electron emission source 36 a of the cathode 36. The electron emission source 36a is formed of an electrode, a coiled filament, or the like. Here, the electron emission source 36a is formed of a coiled filament.

  The anode target 35 has a target surface 35b provided on a part of the outer surface of the anode target. The target surface 35b is formed with a focal point F that emits a utilization X-ray bundle having a second axis d2 that is different from the first direction d1 as a central axis when an electron beam emitted from the cathode 36 is incident thereon. In this embodiment, the target surface 35b is a flat surface. The anode target 35 is made of a metal such as a tungsten alloy. A relatively negative voltage is applied to the cathode 36 and a relatively positive voltage is applied to the anode target 35.

  The vacuum envelope 31 contains an anode target 35 and a cathode 36. The vacuum envelope 31 includes a vacuum container 32, an X-ray transmission window 33, and a metal surface portion 34. The inside of the vacuum envelope 31 is in a vacuum state. The vacuum vessel 32 is formed of a metal such as copper, stainless steel, or aluminum, and an insulator such as glass or ceramics.

  The X-ray transmission window 33 is for taking out the used X-ray flux to the outside. For example, the X-ray transmission window 33 is arranged such that the direction from the focal point F toward the second direction d2 passes through the center position. The X-ray transmission window 33 is provided in the vacuum container 32 in an airtight manner. Here, the X-ray transmission window 33 is made of beryllium. The X-ray transmission window 33 has a thickness in the X-ray transmission direction of 0.1 to 2 mm. In addition, the X-ray transmission window 33 can be formed by using any one of aluminum, titanium, nickel, stainless steel, chromium steel, and iron alloy as a main component.

  The metal surface portion 34 is provided inside the vacuum envelope 31 including the surface side of the vacuum side X-ray transmission window 33. Here, the metal surface portion 34 is set to the ground potential (0 V).

  The X-ray shield member 5 is located between the focal point F in the vacuum envelope 31 and the X-ray transmission window 33. The X-ray shield member 5 has a passing portion that allows the electron beam from the cathode 36 toward the focal point F and the used X-ray flux to pass therethrough. In this embodiment, the X-ray shield member 5 is formed in an annular shape. For this reason, the passing portion is a circular opening 5 a formed in the X-ray shield member 5.

The X-ray shield member 5 is formed of a material that shields at least X-rays. The X-ray shield member 5 shields X-rays that are directed from other than the focal point F toward the X-ray transmission window 33.
The X-ray shield member 5 may be made of a material that shields X-rays and exhibits conductivity. The X-ray shield member 5 may be positioned so that an electron beam traveling in a third direction d3 to be described later passes through the center of the opening 5a. For this reason, the opening 5a is formed symmetrically about the trajectory of the passing electron beam.

  The position of the X-ray shield member 5 is fixed in the vacuum envelope 31. In this embodiment, the X-ray shield member 5 is fixed to the vacuum envelope 31. The X-ray shield member 5 is electrically connected to the metal surface portion 34. The X-ray shield member 5 has the same potential (substantially the same potential) as the vacuum envelope 31 (metal surface portion 34).

  The X-ray shield member 5 may be fixed to a member other than the vacuum envelope 31. The X-ray shield member 5 may be set to have the same potential (substantially the same potential) as the anode target 35.

  The deflecting unit 70 deflects the electron beam emitted from the cathode 36 and causes the electron beam to enter the target surface 35b in a third direction d3 different from the first direction d1. In this embodiment, the deflection unit 70 is a magnetic deflection unit, and more specifically a permanent magnet. The deflection unit 70 is provided outside the vacuum envelope 31 at a position surrounding the trajectory of the electron beam. The deflecting unit 70 uses Lorentz force acting on the electron beam moving by the magnetic field Ha1. Here, the deflecting unit 70 deflects the electron beam close to 90 °.

  Here, a plane in contact with the target surface 35b at the position where the focal point F is formed is defined as a first plane S1. A direction passing through the focal point F and facing the target surface 35b and perpendicular to the first plane S1 is defined as a fourth direction d4. A plane including the second direction d2 and the fourth direction d4 is defined as a second plane S2. A plane including the third direction d3 and the fourth direction d4 is defined as a third plane S3.

  In addition, an angle formed by the third direction d3 from the first plane S1 is α. An angle formed by the third plane S3 on the inner side with respect to the second plane S2 is β. An angle formed by the second direction d2 from the first plane S1 is γ.

The angle α is in the range of 5 ° to 60 °. Although the angle β is not particularly limited, it is any one within the range of −30 ° to + 30 °. The angle α depends on the first direction d1 and the direction of the magnetic field Ha1. The angle γ is not particularly limited, but is set within a range of 5 ° to 25 °, for example. In this embodiment, the angle α is 30 °, the angle β is 0 °, and the angle γ is 15 °.
The magnetic field Ha1 is parallel to the first plane S1, and is perpendicular to the second plane S2 and the third plane S3.

  A high voltage power supply 15 is connected to the X-ray tube 30. The high voltage power supply 15 is for supplying a high voltage to the cathode 36 and the anode target 35. In this embodiment, the high voltage power supply 15 supplies a high voltage only to the cathode 36.

  A tube voltage V is applied between the cathode 36 and the anode target 35 of the X-ray tube 30. When the potential of the anode target 35 is VA and the potential of the cathode 36 is VC, the tube voltage V is VA-VC. The tube voltage V is 20 kV to 200 kV.

  In this embodiment, the high voltage power supply 15 supplies a voltage of −V to the cathode 36. The anode target 35, the metal part of the vacuum envelope 31 including the X-ray transmission window 33, and the X-ray shield member 5 are grounded (0 V).

  The potential of the cathode 36 is not limited to −V, and may be set to any value within the range of −V to 0V (−V ≦ VC ≦ 0). The potential of the anode target 35 is not limited to the ground potential, and may be set to any value within the range of the ground potential to + V (0 ≦ VA ≦ + V). For example, the potential of the metal part of the cathode 36 and the vacuum envelope 31 may be set to 0V, and the potential of the anode target 35 and the potential of the X-ray shield member 5 may be set to + V, respectively.

  In particular, the potential of the cathode 36 is set to be in the range of −V to −V / 2 (−V ≦ VC ≦ −V / 2), and the potential of the anode target 35 is equal to or higher than the ground potential and equal to or lower than + V / 2. When it is set to any one of the ranges (0 ≦ VA ≦ + V / 2), recoil electrons directly hitting the X-ray transmission window 33 can be suppressed.

  In the X-ray tube 30 configured as described above, for example, a negative high voltage of −100 kV or more is applied to the cathode 36. The anode target 35 and the vacuum envelope 31 are grounded. The electron emission source 36a of the cathode 36 is further given a low voltage and current of ± 100 V or less.

  As a result, the electron beam emitted from the cathode 36 is deflected by the deflecting unit 70 and is incident on the target surface 35 b of the anode target 35. Then, X-rays are emitted from the focal point F formed on the target surface 35b, and X-rays (utilized X-ray bundles) are transmitted through the X-ray transmission window 33 and emitted to the outside.

  According to the X-ray apparatus according to the first embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The cathode 36 is set to a negative high potential, and the anode target 35, the vacuum envelope 31 including the X-ray transmission window 33, and the X-ray shield member 5 are grounded.

  The first direction d1 is perpendicular to the target surface 35b, but the angle α can be set to 30 ° by the action of the magnetic field Ha1 by the deflecting unit 70. Recoil electrons jump from the focal point F along the third plane S3 with an angular distribution such that the incident electrons are the largest in the direction of specular reflection at the target surface 35b and the smallest in the direction in which the electrons are incident. Is. Since the electron beam is incident on the target surface 35b from the X-ray transmission window 33 side, direct hit of recoil electrons to the X-ray transmission window 33 can be suppressed, and heating of the X-ray transmission window 33 can be suppressed. Can do. And damage to the X-ray transmission window 33 can be prevented. Note that most of the recoil electrons that jump out of the focal point F impact the inner surface of the vacuum vessel 32 that is out of the X-ray transmission window 33. The above-described effect can be obtained when the angle α is in the range of 5 ° to 60 °.

  Further, since recoil electrons are captured by the vacuum envelope 31 or the capturing body 60 disposed above the target surface 35b described later, the recoil electrons are re-collised with the target surface 35b including the vicinity of the focal point F. Can be suppressed. Thereby, the temperature rise of the target surface 35b (focal point F) and the roughness caused by the target surface 35b can be suppressed, and the occurrence of discharge and the decrease in the output of X-rays can be suppressed. Furthermore, since the emission of X-rays from other than the focal point F can be suppressed, it is possible to suppress a decrease in the clarity of the X-ray image. The above-described effect can be obtained when the angle α is in the range of 5 ° to 60 °.

  The X-ray shield member 5 has an opening 5a. For this reason, it is possible to shield X-rays from other than the focus F toward the X-ray transmission window 33 without blocking the trajectory between the electron beam from the cathode 36 toward the focus F and the used X-ray flux emitted from the focus F. it can.

  Further, as described above, the anode target 35, the vacuum envelope 31 including the X-ray transmission window 33, and the X-ray shield member 5 are grounded. The anode target 35 and the X-ray shield member 5 are at the same potential. For this reason, the X-ray shield member 5 can function as an accelerating electrode that accelerates the electron beam toward the focal point F.

  Furthermore, the X-ray shield member 5 is positioned so that the electron beam traveling in the third direction d3 passes through the center of the opening 5a, whereby the X-ray shield member 5 focuses the electron beam traveling toward the focal point F. Can function as.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time.

  Further, the thickness of the X-ray transmission window 33 is reduced, or the material forming the X-ray transmission window 33 is changed to any one of cheaper aluminum, titanium, nickel, stainless steel, chromium steel, and iron alloy. It is possible to substitute.

  Next, an X-ray apparatus according to the second embodiment will be described. In the second embodiment, another basic concept of the configuration of the X-ray apparatus will be described. In this embodiment, the same functional parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the X-ray apparatus is the same as that of the first embodiment except that the position of the cathode 36 is different and the magnitude of the magnetic field Ha1 that the deflection unit 70 acts on the electron beam is different. The X-ray apparatus is formed in the same manner.

  The cathode 36 emits an electron beam in the first direction d1 along the second plane S2 toward the X-ray transmission window 33 side. The magnetic field Ha1 is parallel to the first plane S1 and perpendicular to the second plane S2 and the third plane S3. Here, the deflecting unit 70 deflects the electron beam close to 180 °. The angle α is in the range of 5 ° to 60 °. The angle β is 0 °. The angle γ is set within a range of 5 ° to 25 °.

  According to the X-ray apparatus according to the second embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The first direction d1 is a direction along the second plane S2 toward the X-ray transmission window 33 side, and the angle α is set to any one within the range of 5 ° to 60 ° by the action of the magnetic field Ha1 by the deflection unit 70. can do. For this reason, the X-ray apparatus according to the second embodiment can obtain the same effects as those of the first embodiment described above.

  In addition, since the cathode 36 can be placed in a lying state so as to be parallel along the first plane S1, the fourth direction can be compared to the case where the cathode 36 is placed in a state of standing in the fourth direction d4. The size of the X-ray tube 30 along d4 can be made more compact.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

  Next, an X-ray apparatus according to a third embodiment will be described. In the third embodiment, another basic concept of the configuration of the X-ray apparatus will be described. In this embodiment, the same functional parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 5, the X-ray apparatus is different from the first embodiment except that the position of the cathode 36 is different and the direction and magnitude of the magnetic field Ha1 that the deflection unit 70 acts on the electron beam is different. It is formed similarly to the X-ray apparatus of the embodiment.

  The cathode 36 emits an electron beam in a first direction d1 that is parallel to the first plane S1 and perpendicular to the third plane S3. The deflecting unit 70 applies the magnetic field Ha1 in a direction inclined from the reverse direction of the fourth direction d4. The magnetic field Ha1 is parallel to the third plane S3 and perpendicular to the plane including the first direction d1 and the third direction d3. Here, the deflecting unit 70 deflects the electron beam by 90 °. The angle α is in the range of 5 ° to 60 °. The angle β is 0 °. The angle γ is set within a range of 5 ° to 25 °.

  According to the X-ray apparatus according to the third embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The first direction d1 is perpendicular to the third plane S3, but the angle α can be set within a range of 5 ° to 60 ° by the action of the magnetic field Ha1 by the deflecting unit 70. For this reason, the X-ray apparatus according to the third embodiment can obtain the same effects as those of the first embodiment described above.

  In addition, since the cathode 36 can be placed in a state of being laid parallel to the first plane S1, the size of the X-ray tube 30 along the fourth direction d4 can be made more compact.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

  Next, an X-ray apparatus according to a fourth embodiment will be described. In the fourth embodiment, another basic concept of the configuration of the X-ray apparatus will be described. In this embodiment, the same functional parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the X-ray apparatus is formed in the same manner as the X-ray apparatus of the third embodiment except that the position of the cathode 36 is different from that of the X-ray apparatus and further includes another deflecting unit. ing.

  The cathode 36 is parallel to the first plane S1 and emits an electron beam in the first direction d1 toward the X-ray transmission window 33 side. The first deflecting unit applies the magnetic field Ha1 in the direction opposite to the fourth direction d4. Here, the first deflecting unit deflects the electron beam by 90 °.

The second deflecting unit further deflects the electron beam deflected by the magnetic field Ha1, and causes the electron beam to enter the target surface 35b in a third direction d3 different from the first direction d1. In this embodiment, the two deflecting units are magnetic deflecting units, more specifically permanent magnets. The two deflecting units are provided outside the vacuum envelope 31 at positions that surround the electron beam trajectory.
The angle α is in the range of 5 ° to 60 °. The angle β is 0 °. The angle γ is set within a range of 5 ° to 25 °.

  According to the X-ray apparatus according to the fourth embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The first direction d1 is a direction toward the X-ray transmission window 33 side, and the angle α is set to 5 ° to 60 ° by the action of the magnetic field Ha1 by the first deflection unit and the action of the magnetic field Ha2 by the second deflection unit. Can be any of those within the range. For this reason, the X-ray apparatus according to the fourth embodiment can obtain the same effects as those of the third embodiment described above.

  In addition, since the cathode 36 can be placed in a state of being laid parallel to the first plane S1, the size of the X-ray tube 30 along the fourth direction d4 can be made more compact.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

  Next, an X-ray apparatus according to a fifth embodiment will be described. In the fifth embodiment, another basic concept of the configuration of the X-ray apparatus will be described. In this embodiment, the same functional parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, the X-ray apparatus is the same as the third one except that the position of the cathode 36 is different and the direction and magnitude of the magnetic field Ha1 that the deflection unit 70 acts on the electron beam is different. It is formed similarly to the X-ray apparatus of the embodiment.

  The cathode 36 is perpendicular to the second plane S2 and the third plane S3, and emits an electron beam in a first direction d1 inclined by an angle α from the first plane S1. The deflecting unit 70 applies the magnetic field Ha1 in the direction opposite to the fourth direction d4. Here, the deflecting unit 70 deflects the electron beam by 90 °. The angle α is in the range of 5 ° to 60 °. The angle β is 0 °. The angle γ is set within a range of 5 ° to 25 °.

  According to the X-ray apparatus according to the fifth embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The first direction d1 is perpendicular to the third plane S3, but is inclined by an angle α from the first plane S1, and the angle α is set to 5 ° to 60 by the action of the magnetic field Ha1 by the deflection unit 70. It can be anywhere within the range of °. For this reason, the X-ray apparatus according to the fifth embodiment can obtain the same effects as those of the third embodiment described above.

  In addition, since the cathode 36 can be placed in a state of being laid parallel to the first plane S1, the size of the X-ray tube 30 along the fourth direction d4 can be made more compact.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

  Next, an X-ray apparatus according to a sixth embodiment will be described. In the sixth embodiment, another basic concept of the configuration of the X-ray apparatus will be described. In this embodiment, the same functional parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 8, the X-ray apparatus is the same as the X-ray apparatus of the fourth embodiment except that the position of the cathode 36 is different and the direction and magnitude of the magnetic field Ha2 are different. Is formed.

  The cathode 36 is inclined by an angle α from the first plane S1, and emits an electron beam in a first direction d1 toward the X-ray transmission window 33 side. The first deflecting unit applies the magnetic field Ha1 in the direction opposite to the fourth direction d4. Here, the first deflecting unit deflects the electron beam by 90 °.

  The second deflecting unit further deflects the electron beam deflected by the magnetic field Ha1, and causes the electron beam to enter the target surface 35b in a third direction d3 different from the first direction d1. In this embodiment, the two deflecting units are magnetic deflecting units, more specifically permanent magnets. The two deflecting units are provided outside the vacuum envelope 31 at positions that surround the electron beam trajectory.

The second deflecting unit applies a magnetic field Ha2 in the direction opposite to the fourth direction d4 to deflect the electron beam by 90 °.
The angle α is in the range of 5 ° to 60 °. The angle β is 0 °. The angle γ is set within a range of 5 ° to 25 °.

  According to the X-ray apparatus according to the sixth embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The first direction d1 is a direction toward the X-ray transmission window 33 side, but the angle α is within a range of 5 ° to 60 ° by the action of the magnetic field Ha1 by the deflecting unit 70 and the action of the magnetic field Ha2 by another deflecting unit. It can be either. For this reason, the X-ray apparatus according to the sixth embodiment can obtain the same effects as those of the fourth embodiment described above.

  In addition, since the cathode 36 can be placed in a state of being laid parallel to the first plane S1, the size of the X-ray tube 30 along the fourth direction d4 can be made more compact.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

Next, modified examples of the angle β of the X-ray apparatus according to the first to sixth embodiments described above will be described.
The angle β is not limited to 0 °, and may be any one within the range of −30 ° to + 30 °. Even in this case, the size of the X-ray shield member 5 (opening 5a) is increased, or the shape of the X-ray shield member 5 (opening 5a) is adjusted to be elliptical although it is not axially symmetric. As a result, X-rays traveling from other than the focal point F to the X-ray transmission window 33 are blocked without blocking the trajectory between the electron beam traveling from the cathode 36 toward the focal point F and the utilization X-ray bundle emitted from the focal point F. Can do.

  As described above, even if the angle β is set, the focal point F is not greatly blurred or distorted, so that it is possible to maintain a contribution to obtaining a better X-ray image. Even if the angle β is set in this way, the number of recoil electrons that impact the X-ray transmission window 33 does not increase, so that the temperature reduction effect of the X-ray transmission window 33 can be maintained. .

  As a method for setting the angle β to any of the range from −30 ° to + 30 °, (1) for example, as shown in FIGS. 9 and 10, the position of the cathode 36 is changed to change the third direction. changing the direction of d3, (2) changing the position of the X-ray transmission window 33 without changing the position of the cathode 36, and changing the direction of the second direction d2, or (3) one or more magnetic fields. Can be accommodated by setting the third direction d3 in a desired direction. The above (3) can be dealt with by using an electric field instead of a magnetic field.

  Next, modified examples of the target surface 35b of the X-ray apparatus according to the first to sixth embodiments described above will be described. The target surface 35b is not limited to a flat surface, and may be a conical surface or a circumferential surface.

  The case where the target surface 35b is a conical surface is, for example, that the X-ray tube 30 is a rotary anode type X-ray tube, the anode target 35 is formed in a disc shape, and the target surface 35b covers one end surface of the anode target 35. The case where it forms is mentioned.

  When the target surface 35b is a circumferential surface, for example, the X-ray tube 30 is a rotary anode type X-ray tube, the anode target 35 is formed in a disk shape, and the target surface 35b is an outer circumferential surface of the anode target 35. Is formed.

Next, a modified example of the X-ray apparatus according to the first to sixth embodiments described above, and a case where the focal point F is moved on the target surface 35b will be described.
The X-ray apparatus may further include another deflecting unit that deflects the electron beam so that the focal point F periodically moves on the target surface 35b. The other deflecting unit deflects the electron beam in a region closer to the cathode 36 than the region where the magnetic field Ha1 of the deflecting unit 70 acts (the region where the magnetic fields Ha1 and Ha2 act when the magnetic field Ha2 acts). is there.

  For example, as shown in FIGS. 11 and 12, the X-ray apparatus further includes a deflection power supply 81 and a deflection power supply control unit 82 in addition to the X-ray tube apparatus 10. The X-ray tube apparatus 10 further includes a deflection unit 80 as another deflection unit.

  The deflecting unit 80 deflects the electron beam in a region closer to the cathode 36 than the region where the magnetic field Ha1 of the deflecting unit 70 acts. The deflection unit 80 is provided outside the vacuum envelope 31 at a position surrounding the trajectory of the electron beam. The deflecting unit 80 deflects the electron beam so that the magnetic field Hb1 acts on the electron beam traveling in the first direction d1 to obtain the deflection angle θ.

  The deflection power supply 81 supplies a voltage to the deflection unit 80. The deflection power supply control unit 82 controls the voltage that the deflection power supply 81 supplies to the deflection unit 80. The deflection unit 80, the deflection power source 81, and the deflection power source control unit 82 form a deflection magnetic field generation unit for moving the focal position.

  The deflection power supply control unit 82 can control the voltage that the deflection power supply 81 supplies to the deflection unit 80 so that the focal point F moves continuously or intermittently. The deflecting unit 80 deflects the electron beam emitted from the cathode 36 in the direction along the third plane S3 by being supplied with the controlled voltage, and the position of the focal point F is the target along the third plane S3. It can be moved on the surface 35b. In other words, the deflecting unit 80 can scan the electron beam periodically (continuously or intermittently) on the target surface 35b.

  In addition, when the X-ray apparatus is mounted on a CT apparatus, scanning can be performed while switching the focal position, so that it can be applied to a flying focus (focal position shift) type CT apparatus.

  Furthermore, since the electron beam is scanned on the target surface 35b at a sufficiently high speed by the deflecting unit 80, an increase in the focus F temperature can be reduced. Therefore, it is possible to use even a fixed anode type X-ray apparatus that cannot be put into practical use because the anode target melts without scanning the electron beam.

  When the angle α is around 90 ° (90 ° ± 20 °), the deflection angle θ of the electron beam needs to be relatively large in order to move the position of the focal point F. For this reason, the deflection power supply 81 needs to supply a relatively high voltage to the deflection unit 80. In this case, it is impossible to realize an X-ray apparatus capable of deflecting an electron beam with energy efficiency.

  On the other hand, when the angle α is in the range of 5 ° to 60 °, the deflection angle θ of the electron beam for moving the focal point F by the same distance as compared with the case where the angle α is around 90 °. Can be reduced. That is, since the voltage supplied from the deflection power supply 81 to the deflection unit 80 can be lowered, the electron beam can be deflected in an energy efficient manner.

  Even in the case of the X-ray apparatus shown in FIG. 11 and FIG. 12, the size of the X-ray shield member 5 (opening 5a) is increased, or the X-ray shield member 5 (opening 5a) is not axially symmetric. X-rays from other than the focal point F without obstructing the trajectory between the electron beam from the cathode 36 toward the focal point F and the utilized X-ray flux emitted from the focal point F. X-rays traveling toward the transmission window 33 can be shielded.

  Next, an X-ray apparatus according to a seventh embodiment will be described. In this embodiment, the X-ray tube is a rotary anode type X-ray tube. Hereinafter, a rotary anode type X-ray apparatus including a rotary anode type X-ray tube will be described. In this embodiment, the same reference numerals are given to the same functional parts as those in the fifth embodiment, and detailed description thereof will be omitted.

  As shown in FIGS. 13 and 14, the X-ray apparatus includes an X-ray tube apparatus 10. Although not shown, the X-ray apparatus also includes the deflection power source 81 and the deflection power source control unit 82 described above. The X-ray tube apparatus 10 includes a rectangular box-shaped housing 20, an X-ray tube 30 accommodated in the housing 20, and a coolant 7 filled in the housing 20 and filling between the X-ray tube 30 and the housing 20. And a stator coil 910 as a rotational drive device, a capturing body 60, a deflecting unit 70, a deflecting unit 80 as another deflecting unit, and a focal position correcting unit 90.

  The housing 20 has two divided parts 20a and 20c which are divided. The division part 20a has a frame part 20b on the outer edge side of the opening end. The division part 20c has a frame part 20d on the outer edge side of the opening end. The frame portion 20d is formed with a frame-like groove portion formed on the side facing the frame portion 20b.

The division parts 20a and 20c are brought into contact with each other so that the frame parts 20b and 20d face each other, and are fastened by a fastener (not shown). The gap between the frame part 20b and the frame part 20d is liquid-tightly sealed by a frame-shaped O-ring provided in the groove part. The O-ring has a function of preventing the coolant 7 from leaking outside the housing 20.
The housing 20 is provided with a rubber bellows 21 to adjust the pressure of the coolant 7. The housing 20 has an X-ray emission window 24 that transmits X-rays and emits the X-rays to the outside.

  The X-ray tube 30 includes a vacuum envelope 31. The vacuum envelope 31 includes a vacuum vessel 32 made of metal, a support member 40, and an insulating member 50. In this embodiment, the insulating member 50 is formed of a high voltage insulating member. The anode target 35 is indirectly attached to the support member 40, and the cathode 36 is indirectly attached to the insulating member 50. The cathode 36 emits an electron beam to the anode target 35. The anode target 35 and the cathode 36 are housed in a vacuum envelope 31.

  The inside of the vacuum envelope 31 is in a vacuum state. The X-ray transmission window 33 is provided in the vacuum container 32 in an airtight manner. Here, the X-ray transmission window 33 is made of beryllium. The metal surface part 34 is provided inside the vacuum vessel 32 including the surface side of the X-ray transmission window 33 on the vacuum side, and is set to ground potential.

  The anode target 35 is formed in a disc shape. The anode target 35 has a target layer 35a provided on a part of the outer surface of the anode target. The target layer 35a emits X-rays (utilized X-ray flux) when the electron beam emitted from the cathode 36 collides with it. The target layer 35a is formed of a metal such as molybdenum, a molybdenum alloy, or a tungsten alloy. The target layer 35a has a target surface 35b. The target surface 35b is a conical surface. The anode target 35 can rotate around the rotation axis A (tube axis). In this embodiment, the anode target 35 is set to the ground potential.

  A cathode support member 37 is connected to the cathode 36. The voltage supply terminal 54 is connected to the cathode 36 through the inside of the cathode support member 37. The voltage supply terminal 54 applies a negative high voltage to the cathode 36 and supplies voltage and current to the electron emission source 36 a of the cathode 36.

  The focusing electrode 9 is located inside the vacuum vessel 32. The focusing electrode 9 focuses the electron beam. The focusing electrode 9 is provided so as to surround the trajectory of the electron beam from the cathode 36 toward the focal point F. The focusing electrode 9 is attached to the cathode support member 37, for example. The adjusted negative high voltage is supplied to the focusing electrode 9.

  The acceleration electrode 8 is located inside the vacuum vessel 32. The acceleration electrode 8 surrounds the trajectory of the electron beam from the cathode 36 and the focusing electrode 9 toward the focal point F, and accelerates the electron beam to enter the target surface 35b. Although not shown, the acceleration electrode 8 is attached to the vacuum vessel 32, and the potential of the acceleration electrode 8 is fixed to the same potential (ground potential) as the vacuum vessel 32 and the anode target 35.

  The X-ray shield member 5 is located between the focal point F in the vacuum envelope 31 and the X-ray transmission window 33. The X-ray shield member 5 has a passing portion that allows the electron beam from the cathode 36 toward the focal point F and the used X-ray flux to pass therethrough. In this embodiment, the X-ray shield member 5 is formed in an annular shape. For this reason, the passing portion is a circular opening 5 a formed in the X-ray shield member 5.

  The X-ray shield member 5 is made of a material that shields X-rays and exhibits conductivity. The X-ray shield member 5 shields X-rays that are directed from other than the focal point F toward the X-ray transmission window 33. The X-ray shield member 5 is positioned so that the electron beam passes through the center of the opening 5a.

  The X-ray shield member 5 is fixed to the vacuum envelope 31. The X-ray shield member 5 is electrically connected to the metal surface portion 34. The X-ray shield member 5 has the same potential (substantially the same potential) as the vacuum envelope 31 (metal surface portion 34).

  The X-ray tube 30 includes a rotor 920, a bearing 930, a fixed body 1, and a rotating body 2. The fixed body 1 is formed in a columnar shape and is fixed to the support member 40. The fixed body 1 supports the rotating body 2 in a rotatable manner. The rotating body 2 is formed in a cylindrical shape and is provided coaxially with the fixed body 1. A rotor 920 is attached to the outer surface of the rotating body 2. The rotating body 2 and the anode target 35 are joined via a joint portion 35c. The rotating body 2 is provided so as to be rotatable together with the anode target 35.

  The support member 40 forms a part of the vacuum envelope 31. The support member 40 is formed of a cylindrical portion 46 and a bottom portion 47 that closes one end side of the cylindrical portion 46. The other end of the cylindrical portion 46 is airtightly joined to the vacuum vessel 32.

  The support member 26 is formed in an annular shape and is hermetically connected to the vacuum vessel 32. The support member 26 is bonded to the insulating member 50. The support member 26 faces the divided portion 20a (housing 20). The support member 26 has an annular groove formed on the side facing the dividing portion 20a. A gap between the support member 26 and the divided portion 20a is sealed by an annular O-ring provided in the groove portion. The O-ring has a function of preventing leakage of the coolant 7 from the gap between the support member 26 and the divided portion 20a to the outside.

  The insulating member 50 is hermetically attached to the support member 26 and forms a part of the vacuum envelope 31. The insulating member 50 has an external end surface 50 </ b> S exposed to the outside of the housing 20. In this embodiment, the outer end surface 50S is a flat surface.

  Inside the insulating member 50, a voltage supply terminal 54 connected to the cathode 36 and led out to the external end face 50S side is provided. In this embodiment, the voltage supply terminal 54 is a high voltage supply terminal. The voltage supply terminal 54 is provided so as to penetrate the external end face 50 </ b> S and supplies a high voltage to the cathode 36.

  The cable 102 is fixed by an insulating member 20 e provided at the opening of the housing 20. The cable 102 is electrically connected to the fixed body 1. The cable 102 sets the anode target 35 to the ground potential via the fixed body 1 and the like, and sets the vacuum vessel 32 (vacuum envelope 31) and the like to the ground potential.

  The high-voltage connector 200 includes a bottomed cylindrical housing 201, a cable 202 having a tip inserted into the housing 201, and the housing 201 filled with the terminal of the cable 202 facing the opening of the housing 201. A fixing portion 203 made of an epoxy resin material to be fixed and a silicone plate 204 made of a silicone resin material inserted between the fixing portion 203 and the outer end surface 50S of the insulating member 50 are provided. In this embodiment, cable 202 is a high voltage cable. The fixing part 203 is an electrical insulating material.

  In this embodiment, the fixing portion 203 as an electrical insulating material of the high voltage connector 200 is in intimate contact with the outer end surface 50 </ b> S of the insulating member 50. Note that the fixing portion 203 may be in direct contact with the outer end surface 50S. The high voltage connector 200 applies a high voltage to the voltage supply terminal 54.

  The X-ray tube apparatus 10 configured as described above is used as follows. When attaching the high voltage connector 200 to the housing 20, the silicone plates 204 are pressed so as to be in close contact with the fixing portion 203 and the outer end surface 50 </ b> S of the insulating member 50.

  An X-ray shielding cap 400 as an X-ray shielding part is detachably attached to the housing 20 so as to cover the high voltage connector 200. The X-ray shielding cap 400 is made of a material containing an X-ray opaque material.

  The coolant 7 is filled in the housing 20 and fills the space between the X-ray tube 30 and the housing 20. As the coolant 7, insulating oil or an aqueous coolant can be used. In this embodiment, an aqueous coolant is used as the coolant 7.

  As shown in FIGS. 7, 13, and 14, the cathode 36 is perpendicular to the second plane S2 and the third plane S3, and emits an electron beam in the first direction d1.

  The deflection unit 70 (permanent magnet) is connected by a yoke 71. Unlike the fifth embodiment, the deflection unit 70 is a direction inclined from the reverse direction of the fourth direction d4, and causes the magnetic field Ha1 to act in a direction along the rotation axis A. Here, the deflecting unit 70 deflects the electron beam by 90 °. The angle α is in the range of 5 ° to 60 °. The angle β is 0 °. The angle γ is set within a range of 5 ° to 25 °.

  The deflecting unit 80 deflects the electron beam in a region closer to the cathode 36 than the region where the magnetic field Ha1 of the deflecting unit 70 acts. The deflection unit 80 is provided outside the vacuum envelope 31 at a position surrounding the trajectory of the electron beam. The deflecting unit 80 applies a magnetic field Hb1 in a direction parallel to the second plane S2 and the third plane S3 and perpendicular to the rotation axis A.

  The deflecting unit 80 applies the magnetic field Hb1 to the electron beam traveling in the first direction d1 so that the electron beam is incident on the target surface 35b with an angle α from the first plane S1, and the focal point F is on the target surface 35b. The electron beam is deflected so as to move periodically. The focal point F moves on the target surface 35b along the third plane S3.

  The focal position correction unit 90 is provided outside the vacuum container 32 at a position surrounding the trajectory of the electron beam. The focal position correction unit 90 generates the correction magnetic field Hc1 in a region closer to the cathode 36 than the region where the magnetic field Ha1 of the deflection unit 70 acts. The focal position correction unit 90 is located on the same plane as the deflection unit 80, is parallel to the second plane S2 and the third plane S3, and applies a correction magnetic field Hc1 in a direction parallel to the rotation axis A. . The correction magnetic field Hc1 is orthogonal to the magnetic field Hb1. The focal position correction unit 90 finely adjusts the position of the focal point F.

  Although not shown, the X-ray apparatus further includes a correction power source that supplies a voltage to the focal position correction unit 90 and a correction power source control unit that controls a voltage supplied from the correction power source to the focal position correction unit 90. The focus position correction unit 90, the correction power source, and the correction power source control unit form another deflection magnetic field generation unit for focus position correction.

  The capturing body 60 is airtightly joined to the vacuum container 32 and forms a part of the vacuum envelope 31. The capturing body 60 can be formed of a metal such as copper, a copper alloy, a grid cup, molybdenum, a molybdenum alloy, or copper tan (a material obtained by impregnating copper with a sponge structure tungsten material). The capturing body 60 is disposed to face the anode target 35. The capturing body 60 captures recoil electrons jumping out from the focal point F. The capturing body 60 has an uneven surface 60 </ b> S on the side facing the anode target 35. The uneven surface 60 </ b> S is formed by a plurality of protrusions formed on the surface of the capturing body 60. The plurality of protrusions are arranged in a direction along the third plane S3 and are formed to extend in a direction perpendicular to the third plane S3.

  Half of the recoil electrons jumping out from the focal point F are captured by the capturing body 60, and the other half are reflected by the capturing body 60. However, since the capturing body 60 has the uneven surface 60S, the remaining half of the recoil electrons can be captured more by the uneven surface 60S due to multiple reflection.

  Inside the capturing body 60, a flow path for the coolant 7 is formed. Even if the capturing body 60 is heated by capturing recoil electrons, the capturing body 60, particularly the uneven surface 60 </ b> S, can be cooled by the coolant 7. The capturing body 60 has an intake port and a discharge port that are open inside the housing 20. The discharge port of the capturing body 60 and the discharge port 20o provided in the housing are connected by a hose or the like.

  A cooling mechanism (not shown) is provided outside the housing 20. The cooling mechanism is connected to the inlet 20 i and the outlet 20 o of the housing 20. The cooling mechanism includes a coolant circulation pump that creates a flow of the coolant 7 in the housing 20 and the capturing body 60, and a heat exchanger that releases heat of the coolant 7 to the outside. For this reason, the coolant 7 is introduced into the housing 20 through the introduction port 20 i and is discharged out of the housing 20 through the discharge port 20 o.

  In this embodiment, the coolant 7 is introduced into the capturing body 60 after being introduced into the housing 20, but is not limited thereto, and may be introduced into the housing 20 after being introduced into the capturing body 60. Good.

  In the X-ray tube apparatus 10 configured as described above, by applying a predetermined current to the stator coil 910, the rotor 920 rotates and the anode target 35 rotates. Next, a predetermined high voltage is applied to the high voltage connector 200.

  The fixed body 1, the bearing 930, the rotating body 2, the joint portion 35c, and the anode target 35 are set to the ground potential via the cable 102. The high voltage applied to the high voltage connector 200 is applied to the cathode 36 via the voltage supply terminal 54. The vacuum envelope 31 including the X-ray transmission window 33 is grounded. The potential of the cathode 36 is set to -V. The potential of the anode target 35 is set to the ground potential. The potential of the X-ray shield member 5 is set to the ground potential.

  As a result, the electron beam emitted from the cathode 36 is deflected by the magnetic field Ha1 and is incident on the target surface 35b of the anode target 35, and a focal point F is formed on the target surface 35b. The position of the focal point F can be corrected by the correction magnetic field Hc1. The focal point F periodically moves on the target surface 35b by the magnetic field Hb1. The utilized X-ray flux emitted from the focal point F is transmitted to the outside through the X-ray transmission window 33 and the X-ray emission window 24.

  According to the X-ray apparatus according to the seventh embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The cathode 36 is set to a negative high potential, and the anode target 35, the vacuum envelope 31 including the X-ray transmission window 33, and the X-ray shield member 5 are grounded.

  The first direction d1 is perpendicular to the third plane S3, but the angle α can be set within a range of 5 ° to 30 ° by the action of the magnetic field Ha1 by the deflecting unit 70. For this reason, the X-ray apparatus according to the seventh embodiment can obtain the same effects as those of the fifth embodiment described above, and the recoil electrons (secondary electrons) directly hit the X-ray transmission window 33. Can be suppressed.

  Further, since recoil electrons scattered upward of the anode target 35 can be captured by the capturing body 60, re-collision of recoil electrons to the target surface 35b including the vicinity of the focal point F can be suppressed. Thereby, the temperature rise of the target surface 35b (focal point F) and the roughness caused by the target surface 35b can be suppressed, and the occurrence of discharge and the decrease in the output of X-rays can be suppressed. Since the emission of X-rays from other than the focal point F can be suppressed, a decrease in the clarity of the X-ray image can be suppressed.

  Even if X-rays are emitted from other than the focal point F, the X-ray shield member 5 can shield X-rays (out-of-focus X-rays) from other than the focal point F toward the X-ray transmission window 33, and thus more X-rays A decrease in the clarity of the image can be suppressed.

  Furthermore, since the cathode 36 can be placed in a state of being lying substantially parallel to the first plane S1, the size of the X-ray tube 30 along the rotation axis A can be made more compact.

  The deflecting unit 80 can scan the electron beam on the target surface 35b periodically (continuously or intermittently). When the X-ray apparatus is mounted on the CT apparatus, scanning can be performed while switching the focal position, and therefore, it can be applied to a flying focus type CT apparatus. Further, since the electron beam is scanned on the target surface 35b at a sufficiently high speed by the deflecting unit 80, an increase in the focus F temperature can be reduced.

  When the angle α is in the range of 5 ° to 60 °, the deflection angle θ of the electron beam for moving the focal point F by the same distance is reduced as compared with the case where the angle α is around 90 °. Can do. That is, since the voltage supplied from the deflection power supply 81 to the deflection unit 80 can be lowered, the electron beam can be deflected in an energy efficient manner.

  As the coolant 7, an aqueous coolant having the highest heat transfer coefficient and containing water as a main component can be used. For this reason, the coolant 7 can most effectively remove the heat transmitted to the vacuum vessel 32, the capturing body 60, the support member 40, the insulating member 50, and the support member 26. Further, since the water-based coolant has a larger specific heat than the insulating oil (about twice that of the insulating oil), the temperature rise of the coolant due to the heat radiation of the X-ray tube 30 is suppressed to a low level.

  Since the support member 40 is in contact with the coolant 7, the heat from the anode target 35 can be effectively dissipated into the coolant 7. Since the support member 26 is in contact with the cooling liquid 7, the heat transmitted from the cathode 36 to the insulating member 50 can be effectively dissipated to the cooling liquid 7, the temperature of the high voltage connector 200 connected to the insulating member 50 can be lowered, and long-term Insulation of the high voltage connector 200 can be ensured.

  The trapping body 60 and the vacuum vessel 32 are heated by receiving most of the recoil electrons jumping out from the focal point F or receiving heat radiation from the anode target 35 that has become high temperature. Since the inside of the body 60 is in contact with the coolant 7, these heats can be effectively dissipated into the coolant 7.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

  Next, an X-ray apparatus according to an eighth embodiment will be described. In this embodiment, the X-ray tube is a rotary anode type X-ray tube. Hereinafter, a rotary anode type X-ray apparatus including a rotary anode type X-ray tube will be described. In this embodiment, the same reference numerals are given to the same functional portions as those in the seventh embodiment, and detailed description thereof will be omitted.

  As shown in FIG. 15, the focal position correction unit 90 is formed by a coil wound around a yoke 71. Another deflection magnetic field generating unit for moving the focal position can supply a constant current to the focal position correcting unit 90 (coil). Thereby, the focal position correction unit 90 can generate the correction magnetic field Hc1 superimposed on the magnetic field Ha1 of the deflection unit 70.

  According to the X-ray apparatus according to the eighth embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The cathode 36 is set to a negative high potential, and the anode target 35, the vacuum envelope 31 including the X-ray transmission window 33, and the X-ray shield member 5 are grounded.

  The focal position correction unit 90 of this embodiment can finely adjust the position of the focal point F as in the seventh embodiment. For this reason, the X-ray apparatus according to the eighth embodiment can obtain the same effects as those of the seventh embodiment described above.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, to reliably reduce the temperature rise of the X-ray transmission window 33, and to move toward the X-ray transmission window 33 from other than the focal point F. An X-ray apparatus capable of reducing the number of lines can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

  Next, an X-ray apparatus according to a ninth embodiment will be described. In this embodiment, the X-ray tube is a rotary anode type X-ray tube. Hereinafter, a rotary anode type X-ray apparatus including a rotary anode type X-ray tube will be described. In this embodiment, the same functional parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The X-ray apparatus according to the ninth embodiment is as shown in FIGS. 16 and 17, and the configuration of the X-ray apparatus can be understood from FIGS. 16 and 17 by referring to the above-described embodiment. is there. Hereinafter, the deflection unit 70, the deflection unit 80, and the focal position correction unit 90 of the X-ray apparatus will be described.

  As shown in FIGS. 3, 16, and 17, the deflecting unit 70 deflects the electron beam emitted from the cathode 36, and causes the electron beam to travel on the target surface 35b in a third direction different from the first direction d1. Incident toward d3. In this embodiment, the deflection unit 70 is a magnetic deflection unit, and more specifically a permanent magnet. The deflection unit 70 is provided outside the vacuum envelope 31 at a position surrounding the trajectory of the electron beam. The deflecting unit 70 uses the magnetic field Ha1 in a direction perpendicular to the second plane S2 and the third plane S3. Here, the deflection unit 70 deflects the electron beam by 90 °. The angle α is in the range of 5 ° to 60 °. The angle β is 0 °. The angle γ is set within a range of 5 ° to 25 °.

  The deflecting unit 80 deflects the electron beam in a region closer to the cathode 36 than the region where the magnetic field Ha1 of the deflecting unit 70 acts. The deflection unit 80 is provided outside the vacuum envelope 31 at a position surrounding the trajectory of the electron beam. The deflecting unit 80 applies a magnetic field Hb1 in a direction parallel to the second plane S2 and the third plane S3 and perpendicular to the rotation axis A.

  The deflecting unit 80 applies the magnetic field Hb1 to the electron beam traveling in the first direction d1, and deflects the electron beam so that the focal point F periodically moves on the target surface 35b. The focal point F moves on the target surface 35b in a direction perpendicular to the third plane S3.

  The focal position correction unit 90 is provided outside the vacuum envelope 31 at a position surrounding the electron beam trajectory. The focal position correction unit 90 generates the correction magnetic field Hc1 in a region closer to the cathode 36 than the region where the magnetic field Ha1 of the deflection unit 70 and the magnetic field Hb1 of the deflection unit 80 act. The focal position correction unit 90 applies the correction magnetic field Hc1 in a direction perpendicular to the rotation plane A and perpendicular to the second plane S2 and the third plane S3. The correction magnetic field Hc1 is orthogonal to the magnetic field Hb1. The focal position correction unit 90 finely adjusts the position of the focal point F.

  Further, the focal position correcting unit 90 may function as another deflecting unit and deflect the electron beam so that the focal point F periodically moves on the target surface 35b. In this case, the focal position correction unit 90 deflects the electron beam by causing the magnetic field Hb2 to act on a region closer to the cathode 36 than the region on which the magnetic fields Ha1 and Hb1 act.

The focal position correcting unit 90 applies the magnetic field Hb2 in a direction perpendicular to the rotation axis A and perpendicular to the second plane S2 and the third plane S3.

  The focal position correction unit 90 applies the magnetic field Hb2 to the electron beam traveling in the first direction d1, and deflects the electron beam so that the focal point F periodically moves on the target surface 35b. The focal point F moves on the target surface 35b in the direction along the third plane S3.

  The X-ray shield member 5 is located between the focal point F in the vacuum envelope 31 and the X-ray transmission window 33. The X-ray shield member 5 has a passing portion that allows the electron beam from the cathode 36 toward the focal point F and the used X-ray flux to pass therethrough. In this embodiment, the X-ray shield member 5 is formed in an annular shape. For this reason, the passing portion is a circular opening 5 a formed in the X-ray shield member 5.

  The X-ray shield member 5 is made of a material that shields X-rays and exhibits conductivity. The X-ray shield member 5 shields X-rays that are directed from other than the focal point F toward the X-ray transmission window 33.

  The X-ray shield member 5 is fixed to the vacuum envelope 31. The X-ray shield member 5 is electrically connected to the metal surface portion 34. The X-ray shield member 5 has the same potential (substantially the same potential) as the vacuum envelope 31 (metal surface portion 34).

  According to the X-ray apparatus according to the ninth embodiment configured as described above, the X-ray tube 30 includes the anode target 35, the cathode 36, the vacuum envelope 31, the X-ray shield member 5, It has. The cathode 36 is set to a negative high potential, and the anode target 35, the vacuum envelope 31 including the X-ray transmission window 33, and the X-ray shield member 5 are grounded.

  Since the X-ray apparatus according to the ninth embodiment can deflect the electron beam by the deflecting unit 70, the same effect as that of the first embodiment described above can be obtained. Direct hit of recoil electrons can be suppressed.

  From the above, it is possible to suppress recoil electrons from directly hitting the X-ray transmission window 33, and to reliably reduce the temperature rise of the X-ray transmission window 33. Can be obtained. Thereby, for example, the resolution of the X-ray image can be improved. In addition, X-rays can be emitted more frequently or X-rays can be continuously emitted for a longer time. Furthermore, the thickness of the X-ray transmission window 33 can be reduced, or the material forming the X-ray transmission window 33 can be replaced with a cheaper material.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  For example, the size and shape of the X-ray shield member 5 and the passage portion of the X-ray shield member 5 are not limited to the above-described embodiments, and can be variously modified. As shown in FIG. 18, the X-ray shield member 5 may be rectangular and the opening 5a may be circular. As shown in FIG. 19, the X-ray shield member 5 may be rectangular (for example, rectangular), and the opening 5a may be elliptical. As shown in FIG. 20, the X-ray shield member 5 and the opening 5a may be oval.

  As shown in FIG. 21, the X-ray shield member 5 may have a slit 5 b as a passing portion that allows the electron beam and the utilized X-ray bundle to pass therethrough. As shown in FIG. 22, the X-ray shield member 5 may have a slit 5 c as a passing portion that allows the electron beam and the utilized X-ray bundle to pass therethrough. In addition, the X-ray shield member 5 can form a slit, for example, by forming it with a pair of plate-like members positioned at a distance from each other.

  As shown in FIG. 23, when the X-ray shield member 5 is formed thick, the inner surface (inner peripheral surface) of the passage portion may be a tapered surface. The tapered surface is shaped so as to gradually expand along the direction in which X-rays (utilized X-ray flux) pass. Thereby, the X-ray shield member 5 can pass X-rays (utilized X-ray flux) in a wider range.

The deflection unit 70 is not limited to a permanent magnet, and may be any unit that acts on a magnetic field that deflects an electron beam. Further, the deflecting unit 70, the deflecting unit 80, and the focal position correcting unit 90 are not limited to the magnetic deflecting unit, and may be an electrostatic deflecting unit. For example, when the deflection unit 70 is an electrostatic deflection unit, the deflection unit 70 is provided inside the vacuum vessel 32 so as to surround the electron beam trajectory, and deflects the electron beam by applying an electric field to the electron beam. be able to.
The present invention is not limited to the above X-ray tube device and X-ray device, but can be applied to various X-ray tube devices and X-ray devices.

  DESCRIPTION OF SYMBOLS 1 ... Fixed body, 2 ... Rotating body, 5 ... X-ray shield member, 5a ... Opening part, 5b ... Slit, 5c ... Slit, 7 ... Coolant, 10 ... X-ray tube apparatus, 20 ... Housing, 24 ... X-ray Radiation window, 30 ... X-ray tube, 31 ... Vacuum envelope, 32 ... Vacuum container, 33 ... X-ray transmission window, 34 ... Metal surface portion, 35 ... Anode target, 35a ... Target layer, 35b ... Target surface, 36 DESCRIPTION OF SYMBOLS ... Cathode, 36a ... Electron emission source, 40 ... Support member, 50 ... Insulating member, 60 ... Capture body, 60S ... Uneven surface, 70 ... Deflection part, 71 ... Yoke, 80 ... Deflection part, 81 ... Deflection power source, 82 ... Deflection power supply control unit, 90 ... focal position correction unit, 102 ... cable, 200 ... high voltage connector, 202 ... cable, A ... rotating shaft, d1 ... first direction, d2 ... second direction, d3 ... third direction, d4 ... 4th direction, F ... Focus, Ha1, Ha2, b1, Hb2, Hc1 ... field, S1 ... first plane, S2 ... second plane, S3 ... third plane, α, β, γ ... angle, theta ... deflection angle.

Claims (18)

A target that forms a cathode that emits an electron beam in a first direction, and a focal point that emits a utilization X-ray bundle having a second direction different from the first direction as a central axis when the electron beam is incident. An anode target having a surface, a vacuum envelope containing the anode target and the cathode, the inside of which is in a vacuum state, and having an X-ray transmission window for taking out the used X-ray bundle to the outside; An X-ray that is located between the focal point and the X-ray transmission window in the envelope and has a passing part that allows the electron beam and the X-ray beam to pass therethrough, and shields X-rays from other than the focal point toward the X-ray transmission window. An X-ray tube comprising a shield member;
A deflection unit that deflects an electron beam emitted from the cathode and makes the electron beam incident on the target surface in a third direction different from the first direction. Tube device. A plane in contact with the target surface at a position where the focal point is formed is a first plane, a direction passing through the focal point and above the target surface and perpendicular to the first plane is a fourth direction, the second direction, and a fourth direction. A plane including a direction is a second plane, a plane including the third direction and the fourth direction is a third plane,
Then,
The angle formed by the third plane on the inner side with respect to the second plane is in a range of −30 ° to + 30 °,
2. The X-ray tube apparatus according to claim 1, wherein an angle formed by the third direction from the first plane is in a range of 5 ° to 60 °.   The X-ray tube apparatus according to claim 1, wherein the anode target and the X-ray shield member have the same potential. The passage is a circular opening formed in the X-ray shield member,
The X-ray shield member according to any one of claims 1 to 3, wherein the X-ray shield member is positioned so that the electron beam traveling in the third direction passes through a center of the opening. Tube device.   The X-ray tube apparatus according to claim 1, wherein the target surface is a flat surface.   The X-ray tube apparatus according to claim 1, wherein the target surface is a conical surface.   The X-ray tube apparatus according to claim 1, wherein the target surface is a circumferential surface.   The X-ray tube apparatus according to claim 1, wherein the deflecting unit is a permanent magnet, and utilizes a Lorentz force acting on the electron beam by a magnetic field.   The X-ray tube apparatus according to claim 8, further comprising a focus position correction unit that finely adjusts the position of the focus.   The X-ray tube apparatus according to claim 9, wherein the focus position correction unit generates a correction magnetic field superimposed on a magnetic field of the deflection unit.   The X-ray tube apparatus according to claim 9, wherein the focal position correction unit generates a correction magnetic field in a region closer to the cathode than a region where the magnetic field of the deflection unit acts.   The X-ray according to claim 1, further comprising another deflecting unit that deflects the electron beam so that the focal point periodically moves on the target surface. Tube equipment.   13. The X-ray tube apparatus according to claim 12, wherein the other deflection unit deflects the electron beam in a region closer to the cathode than a region where the magnetic field of the deflection unit acts.   The X-ray tube apparatus according to claim 12, wherein the other deflection unit further finely adjusts the position of the focal point.   The X-ray tube apparatus according to claim 1, further comprising a capturing body that is disposed to face the anode target and captures recoil electrons that jump out of the focal point.   The X-ray tube apparatus according to any one of claims 1 to 15, wherein an angle formed by the second direction from the first plane is in a range of 5 ° to 25 °. The anode target is fixed, is formed in a cylindrical shape extending along a rotation axis, and is rotatable around the rotation axis;
A fixed body that extends along the rotating shaft and is fitted inside the rotating body and rotatably supports the rotating body;
The X-ray tube apparatus according to claim 1, further comprising a bearing provided between the fixed body and the rotating body.   The X-ray transmission window is formed of any one of aluminum, titanium, nickel, stainless steel, chromium steel, and iron alloy as a main component. X-ray tube apparatus as described in the item.

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