X-ray generator

Abstract

To provide an X-ray generation device capable of obtaining stable X-ray output even in a case where a defect is present in at least one of a target and a window member.SOLUTION: An X-ray generation device 10 comprises an X-ray tube 1 and an electron beam adjustment unit 14. The X-ray tube 1 includes: a housing; an electron gun emitting an electron beam inside of the housing; a target generating an X-ray with incidence of the electron beam inside of the housing; and a window member sealing an opening of the housing and permeating the X-ray therethrough. A defect is present in at least one of the target and the window member. The electron beam adjustment section 14 adjusts the electron beam in such a manner that a first defect is not included in an electron beam irradiated region in the target in a case where the first defect is present in the target, and adjusts the electron beam in such a manner that a second defect is not included in an electron beam projected region in the window member in a case where the second defect is present in the window member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an X-ray generating device. [Background technology]

[0002] There is known an X-ray tube that includes a housing, an electron gun that emits an electron beam within the housing, a target that generates X-rays within the housing by the incidence of the electron beam, and a window member that seals an opening of the housing and allows X-rays to pass through. In such an X-ray tube, the window member is formed into a plate shape using single crystal diamond, and the target may be formed on the inner surface of the window member (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5911323 Summary of the Invention [Problem to be solved by the invention]

[0004] In an X-ray generating device equipped with an X-ray tube as described above, various defects may exist in at least one of the target and the window member. In such a case, for example, when an electron beam is irradiated onto a defect existing in the target, this may lead to a fluctuation in the focal diameter of the X-ray generated on the target, a fluctuation in the amount of X-ray output, etc. On the other hand, it is very difficult to prepare a target and a window member that are free of defects.

[0005] An object of the present invention is to provide an X-ray generating device that can obtain a stable X-ray output even when a defect exists in at least one of the target and the window member. [Means for solving the problem]

[0006] The X-ray generating device of the present invention comprises an X-ray tube and an electron beam adjustment unit. The X-ray tube has a housing, an electron gun that emits an electron beam within the housing, a target that generates X-rays within the housing by the incidence of the electron beam, and a window member that seals the opening of the housing and allows X-rays to pass through, and at least one of the target and the window member has a defect. The electron beam adjustment unit adjusts the electron beam so that, if a first defect is present in the target as the defect, the first defect is not included in the irradiation area of ​​the electron beam on the target, and if a second defect is present in the window member as the defect, the electron beam adjustment unit adjusts the electron beam so that the second defect is not included in the projection area of ​​the electron beam on the window member.

[0007] In this X-ray generating device, the electron beam adjustment unit adjusts the electron beam so that the first defect present in the target is not included in the irradiation area of ​​the electron beam on the target, and / or the second defect present in the window member is not included in the projection area of ​​the electron beam on the window member. Therefore, according to this X-ray generating device, even if a defect exists in at least one of the target and the window member, a stable X-ray output can be obtained. Note that, assuming that the electron beam incident on the target passes through the target, when the window member is disposed at a position where the electron beam transmitted through the target is incident, the projection area of ​​the electron beam on the window member means the irradiation area of ​​the electron beam that is assumed to pass through the target and enter the window member. Also, assuming that the electron beam incident on the target is reflected by the target, when the window member is disposed at a position where the electron beam reflected by the target is incident, the projection area of ​​the electron beam on the window member means the irradiation area of ​​the electron beam that is assumed to be reflected by the target and enter the window member.

[0008] In the X-ray generator of the present invention, the electron beam adjustment unit may have a deflection unit that adjusts the trajectory of the electron beam, thereby adjusting the incidence position of the electron beam on the target so that a first defect present in the target is not included in the irradiation area of ​​the electron beam on the target and / or a second defect present in the window member is not included in the projection area of ​​the electron beam on the window member.

[0009] In the X-ray generator of the present invention, the deflection unit may be an electromagnetic coil, which makes it possible to adjust the trajectory of the electron beam with high precision.

[0010] In the X-ray generator of the present invention, the deflection unit may be a permanent magnet, which makes it possible to adjust the trajectory of the electron beam with a simple configuration.

[0011] In the X-ray generating device of the present invention, the electron beam adjustment unit may adjust an irradiation area of ​​the target with the electron beam, thereby adjusting the irradiation area of ​​the target with the electron beam so that a first defect present in the target is not included in the irradiation area of ​​the target with the electron beam and / or so that a second defect present in the window member is not included in the projection area of ​​the electron beam on the window member.

[0012] In the X-ray generating device of the present invention, the window member may be formed in a plate shape using single crystal diamond, polycrystalline diamond, or mosaic crystal diamond. This allows a window member with excellent X-ray transmission properties, heat resistance, heat dissipation, etc. On the other hand, crystal defects, etc. are likely to occur in the window member, but since the electron beam is adjusted by the electron beam adjustment unit as described above, a stable X-ray output can be obtained.

[0013] In the X-ray generating device of the present invention, the window member may have a surface on the inner side of the housing, and the target may be formed on the surface. This allows a stable X-ray output to be obtained as a transmission type X-ray tube. Furthermore, if the target formed on the surface of the window member has defects such as unevenness, and the defects such as unevenness are irradiated with an electron beam, the target is likely to be damaged, such as peeled off from the window member, but since the electron beam adjustment unit adjusts the electron beam as described above, such damage to the target can be prevented. Effect of the Invention

[0014] According to the present invention, it is possible to provide an X-ray generating device that can obtain a stable X-ray output even when a defect exists in at least one of the target and the window member. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram of an X-ray generating device according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the X-ray tube shown in FIG. [Diagram 3] FIG. 3 is a side view of a portion of the window member shown in FIG. 2. [Figure 4] 3 is a side view showing the trajectory of an electron beam incident on the target shown in FIG. 2. [Diagram 5] FIG. 11 is a cross-sectional view of a modified X-ray tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted. [X-ray generator configuration]

[0017] As shown in Fig. 1, an X-ray generating device 10 includes an X-ray tube 1, a power supply unit 11, a deflection unit 12, and a control unit 13. The X-ray tube 1, the power supply unit 11, and the deflection unit 12 are supported in a case (not shown) made of metal. The deflection unit 12 and the control unit 13 function as an electron beam adjusting unit 14 (details will be described later). As an example, the X-ray tube 1 is a small focus X-ray source, and the X-ray generating device 10 is a device used in X-ray nondestructive inspection for magnifying and observing the internal structure of an inspection target.

[0018] 2, the X-ray tube 1 includes a housing 2, an electron gun 3, a target 4, and a window member 5. As described below, the X-ray tube 1 is configured as a sealed transmission type X-ray tube that does not require replacement of parts.

[0019] The housing 2 has a head 21 and a bulb 22. The head 21 is formed of metal in a cylindrical shape with a bottom. The bulb 22 is formed of an insulating material such as glass in a cylindrical shape with a bottom. An opening 22a of the bulb 22 is airtightly joined to an opening 21a of the head 21. In the X-ray tube 1, the center line of the housing 2 is the tube axis A. An opening 23 is formed in the bottom wall portion 21b of the head 21. The opening 23 is located on the tube axis A. When viewed from a direction parallel to the tube axis A, the opening 23 has, for example, a circular shape with the tube axis A as its center line.

[0020] The electron gun 3 emits an electron beam B in the housing 2. The electron gun 3 has a heater 31, a cathode 32, a first grid electrode 33, and a second grid electrode 34. The heater 31, the cathode 32, the first grid electrode 33, and the second grid electrode 34 are arranged on the tube axis A in this order from the bottom wall portion 22b side of the bulb 22. The heater 31 is composed of a filament, and generates heat when electricity is applied. The cathode 32 is heated by the heater 31 and emits electrons. The first grid electrode 33 is formed in a cylindrical shape, and adjusts the amount of electrons emitted from the cathode 32. The second grid electrode 34 is formed in a cylindrical shape, and focuses the electrons that have passed through the first grid electrode 33 on the target 4. The heater 31, the cathode 32, the first grid electrode 33, and the second grid electrode 34 are electrically and physically connected to a plurality of lead pins 35 penetrating the bottom wall portion 22b of the bulb 22. The focusing state of the electron beam B on the target 4 can be adjusted not only by the second grid electrode 34 but also by the first grid electrode 33.

[0021] The window member 5 seals the opening 23 of the housing 2. The window member 5 is formed in a plate shape by single crystal diamond, polycrystalline diamond, or mosaic crystal diamond (a plurality of crystal members are joined together adjacently in the horizontal direction). The window member 5 is, for example, in the shape of a disk with the tube axis A as the center line. The window member 5 has a first surface 51 and a second surface (surface) 52. The first surface 51 is a surface on the opposite side to the inside of the housing 2, and the second surface 52 is a surface on the inside side of the housing 2. Each of the first surface 51 and the second surface 52 is, for example, a flat surface perpendicular to the tube axis A. The target 4 is formed on the second surface 52 of the window member 5. The target 4 is, for example, formed in a film shape by tungsten. The target 4 generates X-rays R by the incidence of the electron beam B in the housing 2. In this embodiment, the X-rays R generated in the target 4 are transmitted through the target 4 and the window member 5 and emitted to the outside.

[0022] The window member 5 is attached to a mounting surface 24 around the opening 23 in the housing 2. The mounting surface 24 is, for example, a flat surface perpendicular to the tube axis A, and is formed on the head 21. The window member 5 is hermetically joined to the mounting surface 24 via a joining member (not shown) such as a brazing material. In the X-ray tube 1, the target 4 is electrically connected to the head 21, and the target 4 and the window member 5 are thermally connected to the head 21. As an example, the target 4 is set to a ground potential via the head 21. As an example, heat generated in the target 4 by the incidence of the electron beam B is transferred to the head 21 directly and / or via the window member 5, and is released from the head 21 to a heat dissipation section (not shown). In this embodiment, the housing 2, the target 4, and the window member 5 maintain the internal space of the housing 2 at a high degree of vacuum.

[0023] In the X-ray generator 10 configured as above, a negative voltage is applied to the electron gun 3 by the power supply unit 11 with the potential of the target 4 as a reference. As an example, the power supply unit 11 applies a negative high voltage (e.g., −10 kV to −500 kV) to each part of the electron gun 3 via each lead pin 35 while the target 4 is at ground potential. The electron beam B emitted from the electron gun 3 is focused on the target 4 along the tube axis A. The X-rays R generated in the irradiation area B1 of the electron beam B on the target 4 are focused at the irradiation area B1 and transmitted through the target 4 and the window member 5 to be emitted to the outside. [Function of the deflection and control units as electron beam adjustment units]

[0024] Before describing the functions of the deflection unit 12 and the control unit 13 as the electron beam adjustment unit 14, a description will be given of defects present in at least one of the target 4 and the window member 5. In the following description, a defect present in the target 4 is referred to as a "first defect," and a defect present in the window member 5 is referred to as a "second defect."

[0025] As shown in FIG. 3, the second defects 5a are present in the window member 5 formed in a plate shape by single crystal diamond, polycrystalline diamond, or mosaic crystal diamond. The window member 5 may have a plurality of second defects 5a, and the position of each second defect 5a in the window member 5 is random. The second defects 5a present in the window member 5 include "lattice defects occurring inside the single crystal diamond substrate due to nonuniformity during crystal growth of the substrate" (hereinafter simply referred to as "lattice defects"), "surface defects occurring on the surface of the single crystal diamond substrate due to nonuniformity during crystal growth of the substrate" (hereinafter simply referred to as "surface defects"), and "particle defects occurring on the surface of the polycrystalline diamond substrate when polishing the substrate" (hereinafter simply referred to as "particle defects"), as well as polycrystalline regions occurring at the joints when multiple single crystal members are joined to form a mosaic crystal diamond (a combination of lattice defects present inside the substrate and surface defects occurring on the surface of the substrate).

[0026] A first defect 4a exists in the target 4 formed on the second surface 52 of the window member 5. There may be a plurality of first defects 4a in the target 4, and the position of each first defect 4a in the target 4 is random. The first defects 4a existing in the target 4 include "depressions occurring during sputtering of a target material onto the second surface 52 of the window member 5 where surface chipping or particle chipping has occurred" (hereinafter simply referred to as "depressions"), etc.

[0027] When "when lattice defects exist in the window member 5", if the X-rays R generated in the target 4 pass through a region of the window member 5 corresponding to the defects, the X-rays R may be affected by diffraction, etc., and the X-ray intensity may change compared to the X-rays R that pass through a region without defects. When such X-rays R are irradiated to an inspection object, streaky bright lines and / or dark lines may appear in the obtained X-ray image. When "when surface chipping or particle chipping exists in the window member 5" and / or "when a depression exists in the target 4", if the electron beam B is irradiated to a region of the target 4 corresponding to the defects, the target 4 may peel off from the window member 5 starting from the defects, the target 4 may be damaged due to abnormal heating, the focal diameter of the X-rays R generated on the target 4 may change, or the output X-ray amount may change.

[0028] The reason why the target 4 peels off from the window member 5 starting from the defect is that a stress of about 2 GPa occurs at the contact surface between the window member 5 and the target 4 formed by sputtering due to the difference in the linear expansion coefficient between them. The reason why abnormal heat is generated is that the adhesion between the window member 5 and the target 4 is insufficient, resulting in a decrease in heat transfer from the target 4 to the window member 5. The reason why the focal diameter of the X-rays R generated on the target 4 and the output amount of X-rays fluctuate is because the adhesion between the window member 5 and the target 4 is insufficient.

[0029] In the X-ray generating device 10 having the target 4 and the window member 5 as described above, the deflection unit 12 and the control unit 13 function as an electron beam adjustment unit 14. That is, when a first defect 4a exists in the target 4, the deflection unit 12 and the control unit 13 adjust the electron beam B so that the first defect 4a is not included in an irradiation area B1 of the electron beam B on the target 4, and when a second defect 5a exists in the window member 5, the deflection unit 12 and the control unit 13 adjust the electron beam B so that the second defect 5a is not included in a projection area B2 of the electron beam B on the window member 5. Note that in this embodiment, a defect having an area of ​​1 / 100 or more of the spot area of ​​the electron beam B on the target 4 when viewed from the thickness direction of the window member 5 is targeted for adjustment of the electron beam B.

[0030] 2 and 3, assuming that the electron beam B incident on the target 4 passes through the target 4, when the window member 5 is disposed at a position where the electron beam B transmitted through the target 4 is incident, the projection region B2 of the electron beam B on the window member 5 means the irradiation region of the electron beam B that is assumed to pass through the target 4 and be incident on the window member 5. Adjusting the electron beam B so that the first defect 4a is not included in the irradiation region B1 of the electron beam B on the target 4 means adjusting the electron beam B so that the first defect 4a is not included in the irradiation region B1 when viewed from the incidence direction of the electron beam B on the target 4. Adjusting the electron beam B so that the second defect 5a is not included in the projection region B2 of the electron beam B on the window member 5 means adjusting the electron beam B so that the second defect 5a is not included in the projection region B2 when viewed from the incidence direction of the electron beam B on the window member 5.

[0031] As an example, when "a lattice defect exists in the window member 5," if the electron beam B is adjusted so that the second defect 5a is not included in the projection region B2 of the electron beam B on the window member 5, it is possible to prevent the X-rays R transmitted through the lattice defect in the window member 5 from being included in the X-rays R irradiated to the inspection object. Furthermore, as the distance between the projection region B2 of the electron beam B on the window member 5 and the lattice defect in the window member 5 increases, the emission direction of the X-rays R transmitted through the lattice defect in the window member 5 moves away from the front direction (tube axis A) of the window member 5, so that it is possible to further prevent the X-rays R transmitted through the lattice defect in the window member 5 from being included in the X-rays R irradiated to the inspection object.

[0032] In this embodiment, the deflection unit 12 is an electromagnetic coil arranged to surround the head 21 of the X-ray tube 1 as shown in Fig. 2, and adjusts the trajectory of the electron beam B depending on the strength of the magnetic field generated. At this time, the control unit 13 controls the current flowing through the electromagnetic coil. For example, as shown in Fig. 4, when the first defect 4a and the second defect 5a are located on the tube axis A, the deflection unit 12 adjusts the trajectory of the electron beam B so that the electron beam B is incident on a position of the target 4 that is off the tube axis A.

[0033] The deflection unit 12 and the control unit 13 may function as the electron beam adjustment unit 14 during actual operation of the X-ray generation device 10, or may function as the electron beam adjustment unit 14 before actual operation of the X-ray generation device 10. Note that "before actual operation of the X-ray generation device 10" includes timing at the time of shipment inspection of the X-ray generation device 10, timing before regular actual operation of the X-ray generation device 10, etc.

[0034] An example in which the deflection unit 12 and the control unit 13 function as the electron beam adjustment unit 14 during the actual operation of the X-ray generation device 10 is as follows. The control unit 13 receives "information on the output of X-rays R" from the X-ray detection device during the actual operation of the X-ray generation device 10, and controls the deflection unit 12 based on the "information on the output of X-rays R". Specifically, when an abnormality is confirmed in the output of X-rays R (e.g., non-uniformity of X-ray intensity, fluctuation in the focal diameter of X-rays R, fluctuation in X-ray amount, etc.), the control unit 13 controls the deflection unit 12 so that the abnormality is not confirmed in the output of X-rays R. This is because a state in which an abnormality is confirmed in the output of X-rays R corresponds to a "state in which the first defect 4a is irradiated with the electron beam B" and / or a "state in which the second defect 5a is irradiated with the X-rays R", and a state in which an abnormality is not confirmed in the output of X-rays R corresponds to a "state in which the first defect 4a is not irradiated with the electron beam B and the second defect 5a is not irradiated with the X-rays R".

[0035] An example in which the deflection unit 12 and the control unit 13 function as the electron beam adjustment unit 14 before the actual operation of the X-ray generation device 10 is as follows. The control unit 13 receives "information regarding the output of X-rays R" from the X-ray detection device while provisionally operating the X-ray generation device 10 and changing the incident position of the electron beam B on the target 4 by controlling the deflection unit 12. As a result, the control unit 13 stores the "information regarding the output of X-rays R" corresponding to the incident position of the electron beam B on the target 4. Next, based on the "information regarding the output of X-rays R" stored corresponding to the incident position of the electron beam B on the target 4, the control unit 13 controls the deflection unit 12 so that the electron beam B is not incident on an incident position where an abnormality has been confirmed in the output of X-rays R and the electron beam B is incident on an incident position where no abnormality has been confirmed in the output of X-rays R.

[0036] The X-ray detection device may be a device capable of detecting at least one of non-uniformity in X-ray intensity, variation in focal diameter of X-rays R, and variation in X-ray dose. Furthermore, when an abnormality is detected in the output of X-rays R by the X-ray detection device, the control unit 13 may control the deflection unit 12 based on information input by an operator.

[0037] For reference, the X-ray generator 10 may be manufactured as follows. First, when the window member 5 is obtained, the window member 5 is inspected for the presence or absence of the second defect 5a. As an example, the presence or absence of surface defects or particle defects is inspected by an optical microscope, and the presence or absence of lattice defects is inspected by an X-ray diffraction device. Next, if the second defect 5a is present in the window member 5, marking is applied to the window member 5 so that the position of the second defect 5a can be specified. As an example, laser marking is applied to the surface of the window member 5 opposite to the side on which the target 4 is formed. Next, the target 4 is formed on the window member 5. Next, the X-ray tube 1 is assembled with reference to the marking applied to the window member 5 so that the electron beam B is not irradiated to a position of the target 4 corresponding to the second defect 5a. Alternatively, with reference to the marking applied to the window member 5, the deflection amount of the electron beam B is determined so that the electron beam B is not irradiated to a position of the target 4 corresponding to the second defect 5a. In addition, when multiple second defects 5a are present in the window member 5, it is preferable to arrange the window member 5 so that at least one second defect 5a (preferably the largest second defect 5a among the multiple second defects 5a) is located in the outer edge region of the window member 5 (preferably a region outside the region where the electron beam B can be incident by adjusting the deflection state and / or focusing state). [Action and Effects]

[0038] In the X-ray generating device 10, the electron beam adjusting unit 14 adjusts the electron beam B so that a first defect 4a present in the target 4 is not included in an irradiation area B1 of the electron beam B on the target 4, and / or so that a second defect 5a present in the window member 5 is not included in a projection area B2 of the electron beam B on the window member 5. Thus, according to the X-ray generating device 10, a stable output of X-rays R can be obtained even when a defect exists in at least one of the target 4 and the window member 5.

[0039] In the X-ray generating device 10, the electron beam adjusting unit 14 has a deflection unit 12 that adjusts the trajectory of the electron beam B. This makes it possible to adjust the incidence position of the electron beam B on the target 4 so that a first defect 4a present in the target 4 is not included in an irradiation area B1 of the electron beam B on the target 4 and / or so that a second defect 5a present in the window member 5 is not included in a projection area B2 of the electron beam B on the window member 5.

[0040] In the X-ray generating device 10, the deflection unit 12 is an electromagnetic coil, which allows the trajectory of the electron beam B to be adjusted with high precision.

[0041] In the X-ray generating device 10, the window member 5 is formed into a plate shape using single crystal diamond, polycrystalline diamond, or mosaic crystal diamond. This makes it possible to obtain a window member 5 with excellent X-ray transmission properties, heat resistance, heat dissipation, etc. On the other hand, although crystal defects (lattice defects, surface defects, particle defects, etc.) are likely to occur in the window member 5, a stable output of X-rays R can be obtained because the electron beam adjustment unit 14 adjusts the electron beam B as described above.

[0042] In the X-ray generating device 10, the target 4 is formed on the second surface 52 of the window member 5. This makes it possible to obtain a stable output of X-rays R as a transmission type X-ray tube. Furthermore, if the target 4 formed on the second surface 52 of the window member 5 has defects (depressions, etc.) such as unevenness and the defect such as unevenness is irradiated with the electron beam B, the target 4 is likely to be damaged, such as peeled off from the window member 5; however, since the electron beam B is adjusted by the electron beam adjustment unit 14 as described above, such damage to the target 4 can be prevented. [Variations]

[0043] The present invention is not limited to the above embodiment. The X-ray tube 1 may be configured as a sealed reflection type X-ray tube. As shown in FIG. 5, the sealed reflection type X-ray tube 1 is mainly different from the sealed transmission type X-ray tube 1 in that the electron gun 3 is arranged in a housing part 6 on the side of the head 21, and the target 4 is supported by a support member 7 instead of a window member 5. The housing part 6 has a side tube 61 and a stem 62. The side tube 61 is joined to the side wall part of the head 21 so that one opening 61a of the side tube 61 faces the inside of the head 21. The stem 62 seals the other opening 61b of the side tube 61. The heater 31, the cathode 32, the first grid electrode 33, and the second grid electrode 34 are arranged in this order in the side tube 61 from the stem 62 side. A plurality of lead pins 35 penetrate the stem 62. The support member 7 penetrates the bottom wall part 22b of the bulb 22. The target 4 is fixed to a tip portion 71 of a support member 7 in a state inclined on the tube axis A so as to face both the electron gun 3 and the window member 5 .

[0044] In an X-ray generator 10 including the sealed reflection type X-ray tube 1 configured as described above, as an example, with the head 21 and side tube 61 at ground potential, a positive voltage is applied to the target 4 by the power supply unit 11 via the support member 7, and a negative voltage is applied to each part of the electron gun 3 by the power supply unit 11 via a plurality of lead pins 35. The electron beam B emitted from the electron gun 3 is focused on the target 4 along a direction perpendicular to the tube axis A. The X-rays R generated in the irradiation area of ​​the target 4 by the electron beam B are emitted to the outside, with the irradiation area as a focus, through the window member 5. In this case, the deflection unit 12, which is an electromagnetic coil, is arranged to surround the side tube 61.

[0045] Even in an X-ray generator 10 equipped with a sealed reflection type X-ray tube 1, an electron beam adjustment unit 14 adjusts an electron beam B so that a first defect 4a present in a target 4 is not included in an irradiation area B1 of an electron beam B on the target 4, and / or a second defect 5a present in a window member 5 is not included in a projection area B2 of an electron beam B on the window member 5. As shown in FIG. 5, assuming that an electron beam B incident on a target 4 is reflected by the target 4, when a window member 5 is disposed at a position where an electron beam B reflected by the target 4 is incident, a projection area B2 of an electron beam B on a window member 5 means an irradiation area of ​​an electron beam B that is assumed to be reflected by a target 4 and to be incident on a window member 5.

[0046] The X-ray tube 1 may be configured as an open transmission type X-ray tube or an open reflection type X-ray tube. The open transmission type or open reflection type X-ray tube 1 is an X-ray tube in which the housing 2 is configured to be openable, and parts (for example, the window member 5 and each part of the electron gun 3) can be replaced. In an X-ray generating device 10 including an open transmission type or open reflection type X-ray tube 1, the degree of vacuum in the space inside the housing 2 is increased by a vacuum pump.

[0047] In a sealed transmission type or open transmission type X-ray tube 1, the target 4 may be formed on at least a region of the second surface 52 of the window member 5 that is exposed to the opening 23. In a sealed transmission type or open transmission type X-ray tube 1, the target 4 may be formed on the second surface 52 of the window member 5 via another film.

[0048] The electron beam adjustment unit 14 is not limited to having the deflection unit 12, which is an electromagnetic coil, and the control unit 13, as long as it can adjust the electron beam B. For example, the deflection unit 12 may be a permanent magnet arranged outside the housing 2 of the X-ray tube 1. This allows the trajectory of the electron beam B to be adjusted with a simple configuration. The deflection unit 12 may be an electrostatic lens arranged inside the housing 2 of the X-ray tube 1. The electron beam adjustment unit 14 may have a focusing unit (the first grid electrode 33 and / or the second grid electrode 34 of the electron gun 3 described above) that adjusts the irradiation area of ​​the electron beam B on the target 4. This allows the irradiation area of ​​the electron beam B on the target 4 (for example, spot diameter, irradiation position, etc.) to be adjusted so that the first defect 4a existing in the target 4 is not irradiated with the electron beam B and / or the second defect 5a existing in the window member 5 is not irradiated with the X-ray R. In addition, at least two or more arbitrarily selected from an electromagnetic coil, a permanent magnet, an electrostatic lens, and a focusing unit (first grid electrode 33 and / or second grid electrode 34) may be used in combination as the electron beam adjusting unit 14.

[0049] In the case where the window member 5 is formed in a plate shape from single crystal diamond and a polycrystalline portion is formed in a part of it, the polycrystalline portion in the window member 5 may be regarded as the second defect 5a, and the electron beam adjustment unit 14 may adjust the electron beam B so that the X-ray R is not irradiated to the polycrystalline portion. [Explanation of symbols]

[0050] 1...X-ray tube, 2...housing, 3...electron gun, 4...target, 4a...first defect, 5...window member, 5a...second defect, 10...X-ray generator, 12...deflection section, 13...control section, 14...electron beam adjustment section, 23...aperture, 34...second grid electrode (focusing section), 52...second surface (surface), B...electron beam, R...X-ray.

Claims

1. The X-ray tube and the electron beam adjustment unit are provided. The X-ray tube comprises: A housing and an electron gun configured to emit an electron beam within the housing; a target that generates X-rays in response to the electron beam being incident thereon; a window member that seals the opening of the housing and allows the X-rays to pass through, a window member defect exists in the window member, The electron beam adjustment unit adjusts the electron beam so that the window member defect is not included in a projection area of ​​the electron beam on the window member.

2. The X-ray generating device according to claim 1 , wherein the electron beam adjusting unit has a deflection unit that adjusts a trajectory of the electron beam.

3. The X-ray generating device according to claim 2 , wherein the deflection unit is an electromagnetic coil.

4. The X-ray generating device according to claim 2 , wherein the deflection unit is a permanent magnet.

5. 5. The X-ray generating device according to claim 1, wherein the electron beam adjustment unit adjusts an irradiation area of ​​the target with the electron beam.

6. 6. The X-ray generating device according to claim 1, wherein the window member is formed in a plate shape from a single crystal diamond, a polycrystalline diamond, or a mosaic crystal diamond.

7. the window member has a surface on an inner side of the housing, The X-ray generating device according to claim 6 , wherein the target is formed on the surface.

8. The target has a target defect, 8. The X-ray generating device according to claim 1, wherein the electron beam adjusting unit adjusts the electron beam so that the target defect is not included in an irradiation area of ​​the target with the electron beam.

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