JP2019029273A - X-ray tube, X-ray inspection apparatus, and X-ray inspection method - Google Patents

Abstract

To provide an X-ray tube capable of irradiating with X-rays of different X-ray photon energies without switching voltages of a plurality of power supplies and without using a plurality of cathodes.SOLUTION: An X-ray tube 150 includes an anode 2 having anode materials of at least two kinds of materials and having anode materials of two kinds of materials arranged side by side and a cathode 1 which irradiates a cathode line irradiation region of the anode 2 with cathode ray 11 to generate characteristic X-rays having X-ray photon energy corresponding to the material of the anode material from the cathode line irradiation region.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an X-ray tube, an X-ray inspection apparatus using the X-ray tube, and an X-ray inspection method using the X-ray inspection apparatus.

  X-ray image diagnosis performed by X-ray fluoroscopy and X-ray CT (Computed Tomography) examinations uses the attenuation effect of transmitted X-rays that are partially absorbed when irradiated X-rays with a certain energy pass through an object Thus, an X-ray imaging method that is an imaging method for capturing a transmission X-ray image is used. Since this X-ray imaging method is a kind of shadow picture, the subject can be observed non-invasively and non-destructively by the X-ray imaging method. Therefore, the X-ray imaging method has been conventionally used for X-ray imaging of living tissue, non-destructive inspection of industrial products, and the like. In addition, this imaging technique is a typical non-destructive inspection technique for electronic components in the industrial field.

  In the conventional X-ray imaging method, there is a method called dual energy X-ray imaging in which the material of a substance is identified by changing the X-ray photon energy of X-rays emitted from the X-ray tube. In this dual energy X-ray imaging, the X-ray photon energy generated from the anode is controlled by adjusting the tube voltage applied to the X-ray tube using a high-voltage power supply.

  In the conventional X-ray tube, in order to switch the output voltage of the high voltage power supply of the X-ray tube, two settings of the output voltage of the high voltage power supply under different conditions are provided. And this X-ray tube is switched to the setting of the output voltage of the high voltage power supply corresponding to the magnitude of the tube voltage, which is the voltage applied to the X-ray tube, in accordance with the collection timing of the data collection device. The change of the tube voltage of the X-ray tube was achieved (for example, refer to Patent Document 1).

  Further, another conventional X-ray tube includes a plurality of cathodes connected to each of a plurality of high voltage power sources set to different output voltages in advance for one anode material. In this X-ray tube, an X-ray having different X-ray photon energy is obtained by irradiating an anode material with a cathode ray from each of the plurality of cathodes (see, for example, Patent Document 2).

  In addition, another conventional X-ray tube uses a high voltage generator to switch the intensity of X-rays generated from an anode with respect to a rotating anode composed of an anode material made of one type of alloy. The tube voltage applied to the X-ray tube was controlled (for example, refer patent document 3).

JP 2004-363109 A JP 2013-233 A JP 2014-61287 A

  In the dual energy X-ray imaging according to the prior art in Patent Document 1 and Patent Document 3, in order to obtain a desired tube voltage value by changing the output voltage of the high voltage power supply, the low tube voltage value and the high tube voltage value There is a drawback that it takes a long time to switch and the X-ray photon energy of the irradiated X-rays takes time to stabilize.

  Also, in the prior art in Patent Document 2, which was devised to solve the problem related to the stability of X-rays due to voltage fluctuations, since a plurality of cathodes are installed and the number of high-voltage power supplies increases, the X-ray tube is expensive. There was a drawback.

  The present invention has been made to solve the above-described problems, and can irradiate X-rays having different X-ray photon energies without switching the voltages of a plurality of power supplies and without using a plurality of cathodes. The object is to obtain an X-ray tube.

The X-ray tube according to the present invention is:
An anode comprising at least two kinds of anode materials, and an anode lined with two kinds of anode materials;
A cathode ray is irradiated to the cathode ray irradiation area | region in an anode, and the cathode which generate | occur | produces the characteristic X ray which has X-ray photon energy corresponding to the material of an anode material from a cathode ray irradiation area | region is provided.

  In the X-ray tube configured as described above, X-rays having different X-ray photon energies can be irradiated without switching the voltages of a plurality of power supplies and without using a plurality of cathodes.

It is a block diagram of the X-ray tube in Embodiment 1 of this invention. It is a side view of the anode drive part in the X-ray tube of FIG. 1 in Embodiment 1 of this invention. It is a front view of the anode drive part in the X-ray tube of FIG. 1 in Embodiment 1 of this invention. FIG. 3 is a diagram after the operation of the anode driving unit of FIG. 2 in Embodiment 1 of the present invention. FIG. 4 is a diagram after the operation of the anode driving unit of FIG. 3 in Embodiment 1 of the present invention. It is a side view of the anode in the X-ray tube of FIG. 1 in Embodiment 1 of this invention. It is a front view of the anode in the X-ray tube of FIG. 1 in Embodiment 1 of this invention. It is a front view of the 1st modification of the anode in the X-ray tube of FIG. 1 in Embodiment 1 of this invention. It is a side view of the 2nd modification of the anode in the X-ray tube of FIG. 1 in Embodiment 1 of this invention. It is a front view of the 2nd modification of the anode in the X-ray tube of FIG. 1 in Embodiment 1 of this invention. It is a X-ray photon energy distribution of the X-rays generated from the anode when indium is used as the anode of the X-ray tube according to Embodiment 1 of the present invention. It is a X-ray photon energy distribution of the X-rays generated from the anode when tungsten is used as the anode of the X-ray tube in the first embodiment of the present invention. It is the X-ray photon energy distribution of the X-rays generated from the anode when gold is used for the anode of the X-ray tube in Embodiment 1 of the present invention. It is a change figure of the laser beam incident position to the two-dimensional sensor corresponding to the displacement of the anode of FIG. 1 in Embodiment 1 of this invention. It is a block diagram of the X-ray inspection apparatus in Embodiment 2 of this invention. It is a control flowchart of the X-ray inspection apparatus in Embodiment 2 of this invention. It is a block diagram of the modification of the X-ray inspection apparatus in Embodiment 2 of this invention.

  Hereinafter, the X-ray tube, the X-ray inspection apparatus, and the X-ray inspection method according to the embodiment of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals, and the description thereof is omitted. The drawings used in the following description are schematic diagrams used for easy understanding, and the ratio of each dimension may be different from the actual one. Of course, there are also portions having different dimensional relationships and ratios between the drawings. It should be noted that the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications without departing from the spirit of the present invention.

FIG. 1 is a configuration diagram of an X-ray tube according to Embodiment 1 for carrying out the present invention.
The X-ray tube 150 according to the present embodiment includes a cathode 1, an anode 2, an anode driving unit 3, a laser light source 4, a displacement sensor 5 including a two-dimensional sensor 5, and an X-ray tube case 6. Yes. In the X-ray tube case 6, a cathode 1, an anode 2, an anode driving unit 3, a laser light source 4, and a two-dimensional sensor 5 are housed. The cathode 1 is fixed to the X-ray tube case 6.

  The cathode 1 is connected to the negative electrode side of the high voltage power supply 7. The anode 2 is connected to the positive electrode side of the high voltage power supply 7. Here, the high-voltage power supply 7 refers to a power supply that applies a voltage of several tens of kV to several hundreds of kV, and is simply referred to as a power supply hereinafter. A voltage of several tens to several hundreds kV is applied between the cathode 1 and the anode 2 by the power source 7.

  Two electromagnetic lenses 8 are provided between the cathode 1 and the anode 2. A cathode line 11 emitted from the cathode 1 through a high voltage applied between the cathode 1 and the anode 2 passes between the two electromagnetic lenses 8. By applying a voltage between the two electromagnetic lenses 8 to generate an electric field, the cathode line 11 is focused on the surface of the anode 2 and converged.

  The surface of the anode 2 is irradiated with laser light 41 emitted from the laser light source 4. The laser beam 41 is reflected on the surface of the anode 2 to generate laser reflected light 42. The two-dimensional sensor 5 receives the laser reflected light 42 and detects the reflection position on the anode 2. By irradiating the anode 2 with the cathode line 11, X-rays 12 are generated from the surface of the anode 2. The generated X-ray 12 is used for X-ray fluoroscopy and CT analysis. The X-ray 12 passes through an X-ray window 61 provided in the X-ray tube case 6 and is emitted out of the X-ray tube 150. The X-ray window 61 needs to be made of a material that hardly absorbs X-rays. For example, as the material of the X-ray window 61, a material such as beryllium is appropriate.

  The anode 2 is rotatably supported by the anode driving unit 3. A high voltage is applied to the anode 2 by a power source 7. For this reason, the contact part of the anode 2 and the anode drive part 3 needs to be in the state electrically insulated. For example, it is conceivable to install a ceramic insulator 21 having low electrical conductivity at the contact portion. The contact portion between the anode 2 and the anode driving unit 3 may be of any insulating structure as long as the voltage of several hundred kV applied by the power supply 7 is insulated.

  FIG. 2 is a side view of the anode driving unit in the X-ray tube of FIG. 1 in the present embodiment. FIG. 3 is a front view of an anode driving unit in the X-ray tube of FIG. 1 in the present embodiment. Here, the side view is a view seen from a direction perpendicular to the plane including the driving directions of the rotating shaft 32 and the Y-axis driving unit 34. Further, the front view is a view seen in the direction along the rotation shaft 32 and from the rotation shaft 32 toward the motor 31. The configuration of the anode drive unit 3 of the present embodiment will be described with reference to FIGS. 2 and 3.

  The anode driving unit 3 is fixed to the X-ray tube case 6 and supports the motor 31. The motor 31 rotates the rotating shaft 32. The anode 2 is attached to the tip of the rotating shaft 32. The anode drive unit 3 that supports the motor 31 has at least three degrees of freedom that are orthogonal to each other. That is, the anode driving unit 3 includes an X-axis driving unit 33, a Y-axis driving unit 34, and a Z-axis driving unit 35. The drive direction of the Z-axis drive unit 35 coincides with the axial direction of the rotary shaft 32. Each of the X-axis drive unit 33, the Y-axis drive unit 34, and the Z-axis drive unit 35 is connected to wiring for supplying a drive control signal from the outside (not shown). Therefore, the X-axis drive unit 33, the Y-axis drive unit 34, and the Z-axis drive unit 35 can be easily driven by an external signal.

FIG. 4 is a diagram after the operation of the anode driving unit of FIG. 2 in the present embodiment. FIG. 5 is a diagram after the operation of the anode driving unit of FIG. 3 in the present embodiment. The operation of the anode drive unit 3 will be described with reference to FIGS. 4 and 5.
4 and 5 are diagrams after the X-axis drive unit 33, the Y-axis drive unit 34, and the Z-axis drive unit 35 are respectively driven and the position of the motor 31 is moved. By driving the X-axis drive unit 33 to 33 ′, the Y-axis drive unit 34 to 34 ′, and the Z-axis drive unit 35 to 35 ′, the position of the motor 31 moves to 31 ′. The position of the rotating shaft 32 connected to the shaft of the motor 31 moves to the position 32 ′. Along with this, the position where the cathode line 11 irradiates the anode 2 attached to the tip of the rotating shaft 32 can be displaced. For this reason, the anode drive part 3 can change freely the position which the cathode line 11 irradiates to the anode 2. FIG. The position where the motor 31 moves is not limited to the position shown in FIGS.

FIG. 6 is a side view of the anode in the X-ray tube of FIG. 1 in the present embodiment. FIG. 7 is a front view of the anode in the X-ray tube of FIG. 1 in the present embodiment. The structure of the anode 2 in the present embodiment will be described with reference to FIGS. 6 and 7.
6 and 7, the anode 2 is a structure having a side surface that is a truncated cone-shaped side surface, a circular upper base, and a circular lower base having a radius larger than the upper base. . The shape of the anode 2 may be a conical shape. A rotation shaft 32 connected to the shaft of the motor 31 is attached to the center of the lower bottom surface of the anode 2. The anode 2 is rotated by driving the motor 31. The X-ray tube 150 has a so-called rotary anode type structure.

  The anode 2 in the present embodiment has two first anode materials 22 and two second anode materials 23 which are anode materials of two kinds of materials. The anode 2 is configured such that the first anode material 22 and the second anode material 23 are alternately arranged in the circumferential direction which is the rotation direction on the side surface portion of the anode 2. The anode 2 may have at least two types of anode materials. Further, the rotation of the anode 2 may be a continuous rotation or a step rotation that rotates with a time interval.

  When the cathode 2 is irradiated onto the rotating anode 2, two second anode materials are produced twice, once for each of the two first anode materials 22, while the anode 2 rotates once. The cathode ray 11 is irradiated twice in total, once every 23. Therefore, X-rays 12 in which characteristic X-rays are added to white X-rays are generated from the cathode ray irradiation region where the cathode rays 11 are irradiated on the side surface portion of the anode 2.

  FIG. 8 is a front view of a first modification of the anode in the X-ray tube of FIG. 1 in the present embodiment. In FIG. 8, the anode 2a of the first modified example is an anode material of three kinds of materials, one first anode material 22, one second anode material 23, and one third anode material. An anode material 24 is provided. The first anode material 22, the second anode material 23, and the third anode material 24 are arranged in order in the circumferential direction, which is the counterclockwise rotation direction in FIG. 2 is configured.

  When the cathode line 11 is irradiated to the rotating anode 2a of the first modification, the first anode material 22, the second anode material 23, and the anode 2a of the first modification rotate once, The cathode line 11 is irradiated once to the third anode material 24. Therefore, X-rays 12 in which characteristic X-rays corresponding to the material of the anode material irradiated with the cathode rays 11 are added to the white X-rays are generated from the cathode ray irradiation region on the side surface portion of the anode 2.

  6 and 7 show an example in which two different first anode materials 22 and second anode materials 23 are alternately arranged in an annular shape, but as shown in FIG. You may attach the anode material of a different material more than a kind in arbitrary orders.

  FIG. 9 is a side view of a second modification of the anode in the X-ray tube of FIG. 1 in the present embodiment. FIG. 10 is a front view of a second modification of the anode in the X-ray tube of FIG. 1 in the present embodiment. 9 and 10, the anode 2b of the second modified example includes a side surface portion including the side surface of the trapezoidal cross section, an upper bottom portion including the upper bottom of the trapezoidal cross section, and a lower bottom portion including the lower bottom of the trapezoidal cross section, It is a quadrangular prism structure having a predetermined length in a direction perpendicular to the trapezoidal cross section. The anode 2b of the second modified example includes a first anode material 22 and a second anode material 23, which are anode materials of two kinds of materials. The first anode material 22 and the second anode material 23 are alternately arranged in a direction perpendicular to the trapezoidal cross section of the anode 2. The anode 2b of the second modified example is supported by a linear rail guide 25 so as to be movable along the direction in which the first anode material 22 and the second anode material 23 are arranged. The anode 2b of the second modified example can reciprocate linearly in the direction of the arrow R shown in FIG. 10 along the rail guide 25 when the Y-axis drive unit 34 of the anode drive unit 3 is driven. it can. The reciprocating means is not limited to the Y-axis drive unit 34, and may be driven by, for example, hydraulic pressure or air pressure such as an air cylinder.

  While the anode 2b of the second modification makes one reciprocal linear motion, the first anode material 22 is irradiated with the cathode line 11 four times and the second anode material 23 is irradiated four times. Similar to the other examples described above, X-rays 12 in which characteristic X-rays are added to white X-rays are generated from the cathode-ray irradiation region on the side surface of the anode 2.

  If the thermal distortion of the anode 2 does not matter even if the side surface of the anode material is irradiated with the cathode ray 11 and the side surface generates heat, the shape of the anode 2 is a truncated cone shape, a cone shape, or It is not limited to a linear shape.

  FIG. 11 is an X-ray photon energy distribution of X-rays generated from the anode when indium is used as the anode of the X-ray tube in the present embodiment. FIG. 12 is an X-ray photon energy distribution of X-rays generated from the anode when tungsten is used as the anode of the X-ray tube in the present embodiment. FIG. 13 is an X-ray photon energy distribution of X-rays generated from the anode when gold is used for the anode of the X-ray tube in the present embodiment. 11 to 13, the horizontal axis represents X-ray photon energy. The vertical axis represents the relative photon number normalized by an arbitrary number of photons.

  11 to 13 show the X-ray photon energy distribution of X-rays 12 generated from each anode material when a high voltage of 100 kV is applied to the cathode 1 among the voltages of the high-voltage power source that is a candidate for the anode material. Each is illustrated. Specifically, FIGS. 11 to 13 are generated when indium (indicating In in FIG. 11), tungsten (indicating W in FIG. 12), or gold (indicating Au in FIG. 13) is used as an anode material. X-ray photon energy distribution is shown respectively. The value of In: 28.508 [keV] in FIG. 11, the value of W: 58.856 [keV] in FIG. 12, and the value of Au: 68.177 [keV] in FIG. It is the value of the X-ray photon energy of the portion corresponding to X-rays. In FIG. 11 to FIG. 13, a broad portion distributed widely is an X-ray photon energy distribution corresponding to continuous X-rays derived from braking X-rays. Since continuous X-rays are also called white X-rays, the continuous X-rays are hereinafter referred to as white X-rays.

  When attention is paid only to the continuous X-ray part, the maximum X-ray photon energy value and the X-ray photon energy value that is the maximum number of photons are the voltage value of the high-voltage power source applied between the cathode and the anode, that is, the tube voltage. It is determined by the current value, that is, the tube current. For this reason, even if the anode material is changed, the X-ray photon energy distribution of white X-rays does not change.

  On the other hand, characteristic X-rays have X-ray photon energy specific to the material of the anode material that is the generation source. From this, the characteristic X-rays of FIGS. 11 to 13 have X-ray photon energy distributions showing sharp peaks derived from the respective materials of indium, tungsten, and gold. The line photon energy value varies. Thereby, the X-ray photon energy distribution of the X-ray 12 generated from the first anode material 22 and the X-ray photon energy distribution of the X-ray 12 generated from the second anode material 23 are the characteristic X-rays of each anode material. Differ by the X-ray photon energy.

  Further, the transmissivity when the X-ray 12 passes through the sample depends on the X-ray photon energy of the X-ray 12 and the X-ray absorption coefficient of the substance that becomes the sample through which the X-ray 12 passes. The X-ray absorption coefficient, which is a value unique to the substance, depends on the X-ray photon energy of the X-ray 12. Further, the X-ray absorption coefficient has a feature that it increases in the vicinity of the X-ray absorption edge. In order to use this feature, a substance is first irradiated with X-rays 12 under a condition that results in a plurality of different X-ray photon energy distributions, and a plurality of transmitted X-ray images are acquired. Then, the material of the substance can be identified by calculating the X-ray absorption coefficient from the luminance of each transmitted X-ray image. This identification method is referred to as dual energy X-ray imaging (or dual energy X-ray CT analysis).

  In order to perform dual energy X-ray imaging, it is necessary to individually irradiate the sample to be investigated with the X-rays 12 generated under the condition of a plurality of X-ray photon energy distributions. For this reason, the X-ray tube which can control X-ray photon energy to a different value is needed. In the X-ray tube 150, the cathode line 11 is generated by a high voltage applied from an external power source between the cathode and the anode. Then, X-rays 12 are generated from the focal point where the cathode line 11 is applied to the anode 2. The generated X-ray 12 is irradiated to the sample to be investigated. The intensity of the transmitted X-ray, which is the X-ray 12 that has passed through the sample, is measured with respect to the intensity of the incident X-ray, which is the X-ray 12 that enters the sample and has a predetermined X-ray photon energy. And the intensity | strength of a transmission X ray is similarly measured with respect to the incident X ray which changed the X ray photon energy of the X ray 12. FIG. With respect to the incident X-rays having these two different X-ray photon energies, the ratio of the intensity of the incident X-rays to the intensity of the transmitted X-rays and the X-ray absorption coefficient can be obtained to specify the material of the sample to be investigated.

Therefore, the X-ray tube 150 in the present embodiment includes at least two kinds of anode materials, and the cathode 2 is irradiated to the anode 2 in which the anode materials of the two kinds of materials are arranged, and the cathode 2 irradiation region in the anode 2. And a cathode 1 for generating characteristic X-rays having X-ray photon energy corresponding to the material of the anode material from the cathode ray irradiation region.
When the cathode ray irradiation region moves from the anode material of the first type material to the anode material of the second type material, the anode 2 has a characteristic having different X-ray photon energies corresponding to the material of the anode material. X-rays are generated from the cathode ray irradiation region.

  With this configuration, the X-ray tube 150 according to the present embodiment allows dual energy X-rays to irradiate X-rays having different X-ray photon energies without switching the voltages of a plurality of power supplies and without using a plurality of cathodes 1. Imaging can be performed.

Further, in FIGS. 6 to 8 of the present embodiment, the anode 2 is made of the anode material of the first type and the material of the second type by the rotation of the rotating shaft 32 connected to the motor 31. The anode material is moved in the direction in which the anode material is arranged.
Therefore, even with this configuration, the X-ray tube 150 in the present embodiment can irradiate X-rays having different X-ray photon energies without switching the voltages of the plurality of power supplies and without using the plurality of cathodes 1. Energy X-ray imaging can be performed.

  The effect of the present invention can be theoretically obtained even in a transmission X-ray generation system using X-rays 12 generated from the anode back surface when the anode material is formed into a disk shape and the cathode surface is irradiated with cathode rays. . However, in order to generate X-rays 12, it is necessary to reduce the thickness of the disc-shaped anode. For this reason, distortion of the anode material is likely to occur due to heat generated by irradiation of the cathode ray. Therefore, the intensity of the X-ray 12 generated by the rotary anode in this embodiment can be made larger than the intensity of the X-ray 12 generated by the transmission-type anode. Therefore, the rotary anode of the present embodiment has an advantage that the time required to obtain the desired integrated amount of X-rays 12 can be shortened compared to the transmission type anode.

FIG. 14 is a change diagram of the laser light incident position on the two-dimensional sensor corresponding to the displacement of the anode of FIG. 1 in the present embodiment. The two-dimensional sensor 5 in the present embodiment will be described with reference to FIG.
The two-dimensional sensor 5 irradiates laser light 41 toward the displacement measurement region on the side surface of the anode 2 and fixes the laser light source 4 fixed to the X-ray tube case 6 and the laser light 41 reflected on the side surface of the anode 2. It has a two-dimensional sensor 5 that receives the reflected laser beam 42 and is fixed to the X-ray tube case 6. The two-dimensional sensor 5 may be a detector having sensitivity in the region of the emission wavelength of the laser reflected light 42. For example, a CCD camera is suitable. Further, the positional relationship between the anode 2, the laser light source 4, and the two-dimensional sensor 5 may be a positional relationship that does not obstruct the optical path between the cathode line 11 and the X-ray 12. Further, the laser light 41 irradiated from the laser light source 4 is incident on the side surface of the anode 2 with an incident angle of less than 90 °, and the laser reflected light 42 reflected at the same angle as the incident angle is the two-dimensional sensor 5. What is necessary is just to install the two-dimensional sensor 5 in the position which injects perpendicularly into the center part. The incident angle of the laser beam 41 with respect to the side surface of the anode 2 is preferably 5 ° or more and less than 30 °. As a result, the two-dimensional sensor 5 can sensitively detect the optical path variation of the laser reflected light 42 due to the displacement of the anode 2.

  Further, the position of the laser light irradiation region that is the region irradiated with the laser light 41 on the side surface of the anode 2 is not limited. Since the laser light irradiation region coincides with the focal point A that is the cathode ray irradiation region that becomes the X-ray generation region, it is synonymous with the monitoring of the cathode ray irradiation region that is the position where the cathode ray 11 is irradiated. For this reason, it is preferable to install the two-dimensional sensor 5 so that the laser beam 41 and the cathode ray 11 are irradiated at the same position.

  Similarly, referring to FIG. 14, a displacement detection method of the two-dimensional sensor 5 and a failure when the displacement of the two-dimensional sensor 5 occurs will be described. When the anode 2 is present at a reference position with respect to the cathode 1, the laser beam 41 is irradiated toward the focal point A on the side surface of the anode 2. The laser reflected light 42 reflected at the focal point A at the same angle as the incident angle enters the central point B in the direction along the light receiving surface of the two-dimensional sensor 5 in FIG. At this time, the cathode line 11 is also adjusted to be focused at the focal point A. For this reason, X-rays 12 generated from the side surface of the anode 2 are also emitted from the focal point A.

  Next, when the anode 2 is shifted to the position of the anode 2 ′, the position irradiated with the laser light 41 is also shifted from the focal point A to the point A ′. For this reason, the laser reflected light 42 ′ generated at the point A ′ is incident on the point B ′ at a position shifted from the point B where the original laser reflected light 42 enters the two-dimensional sensor 5. In this case, the position at which the cathode line 11 is applied to the anode 2 also deviates from the conventional focal point A. For this reason, the stability of the X-ray 12 is greatly impaired.

  In the X-ray tube 150 of the present embodiment, in order to prevent the irradiation position of the cathode ray 11 from deviating from the focal point A, the signal of the two-dimensional sensor 5 is constantly monitored, and the point B which is the incident point of the laser reflected light 42 A shift which is a displacement amount from point to point B ′ is detected. In this case, a drive signal is output so as to return the incident point from the point B ′ to the point B, and at least one of the X-axis drive unit 33, the Y-axis drive unit 34, and the Z-axis drive unit 35 of the anode drive unit 3 is set. Modify to drive. Then, the X-ray photon energy of the X-ray 12 is switched by rotating the anode 2. That is, the X-ray tube 150 of the present embodiment is connected to the anode 2 to move the anode 2 with respect to the cathode ray irradiation region, the focus position that is the position of the focus A of the cathode line 11, and the cathode ray irradiation. And a two-dimensional sensor 5 which is a focal position detector for detecting a deviation from the position of the region. The anode driving unit 3 moves the anode 2 in accordance with the deviation detected by the two-dimensional sensor 5 that is a focus position detector, and moves the position of the cathode ray irradiation region to the focus position that is the position of the focus A.

  With this configuration, the focal point A in FIG. 14 where the X-ray 12 is generated is kept at a predetermined position with reference to the X-ray window 61 provided in the cathode 1, that is, the X-ray tube case 6 fixed to the cathode 1. Be drunk.

  In the prior art in Patent Document 2 devised to solve the problem related to the stability of X-rays due to voltage fluctuations, since a plurality of cathodes are installed, the cathode rays are irradiated to the anode from different directions. become. For this reason, the irradiation optical axis of X-rays generated from the focal point is not on the same optical axis. In the field of X-ray imaging, particularly cone beam X-ray imaging, the shape of the focal point, which is an X-ray generation region, strongly affects the focus of an image. Therefore, it is necessary to avoid as much as possible the state change such as the focus shape and the degree of focusing of the cathode ray at the focus. Further, in the case of CT imaging that requires an imaging time longer than that of a single transmission image, it is important to keep the state of irradiation X-rays constant throughout the imaging time.

The X-ray tube 150 in the present embodiment solves the above-described conventional problems, and increases the distortion of the side surface portion due to heat concentration due to the cathode wire 11 not moving with respect to the side surface portion of the anode material. Can be suppressed.
Even if the X-ray photon energy of the X-ray 12 is switched by driving the anode driving unit 3, the optical path of the X-ray 12 can be kept constant. Further, by increasing the rotation speed of the motor 31, the X-ray photon energy of the X-ray 12 can be switched in a short time.

  In the present embodiment, the generation of the X-ray 12 while driving the motor 31 has been described. However, the motor 31 is generated only when the X-ray 12 is generated in a stopped state and the X-ray photon energy is changed. The rotational speed of the motor 31 may be adjusted so as to drive the motor. The driving method of the anode driving unit 3 needs to change the X-ray photon energy of the X-ray 12 as needed. On the other hand, the driving method of the anode driving unit 3 is suitable for applications that do not require high-speed switching. As an application that does not require high-speed switching, for example, it is conceivable to use the X-ray tube 150 of the present embodiment for fluoroscopy and various physical analyses.

  Further, in the present embodiment, the configuration in which the anode driving unit 3 is driven to move the anode 2 relative to the cathode 1 fixed to the X-ray tube case 6 has been described. The anode 2 may be fixed and the cathode 1 may be moved relative to the anode 2. The means for moving the cathode 1 may have the same configuration as the X-axis drive unit 33, the Y-axis drive unit 34, and the Z-axis drive unit 35 in the anode drive unit 3, or the X-axis drive unit 33. The Y-axis drive unit 34 and the Z-axis drive unit 35 may have any configuration. For this reason, when the cathode 1 moves relative to the anode 2, the position of the anode 2 irradiated with the cathode line 11 can be changed. That is, the cathode 1 moves the cathode ray irradiation region in the direction in which the anode material of the first type material and the anode material of the second type material are arranged.

  Therefore, even with this configuration, the X-ray tube 150 in the present embodiment can irradiate X-rays having different X-ray photon energies without switching the voltages of the plurality of power supplies and without using the plurality of cathodes 1. Energy X-ray imaging can be performed.

Embodiment 2. FIG.
FIG. 15 is a configuration diagram of an X-ray inspection apparatus according to Embodiment 2 for carrying out the present invention.
15, X-ray tube 150 in X-ray inspection apparatus 200 according to the present embodiment is different from X-ray tube 150 in FIG. 1 of the first embodiment in the following points.
The X-ray inspection apparatus 200 according to the present embodiment includes an X-ray tube 150 in FIG. 1 of the first embodiment, a sample stage 120 that moves the sample 110, and an X-ray window 61 provided in the X-ray tube case 6. And an X-ray camera 100 installed on the optical axis of the X-rays 12 irradiated via the control unit 90.

The X-ray tube 150 irradiates the X-ray 12 to an X-ray irradiation region that is a region irradiated with the X-ray 12 in the sample 110.
The sample stage 120 includes a motor 121 and a sample fixing unit 122 that is connected to the rotation shaft of the motor 121 and fixes the sample 110. The motor 121 of the sample stage 120 can rotate the sample 110 by a desired angle.
That is, the sample stage 120 moves the sample 110 to the X-ray irradiation region where the X-ray 11 emitted from the X-ray tube 150 is irradiated to the sample 110.

  The X-ray camera 100 that is an X-ray intensity detection unit detects the X-ray intensity that is the number of photons of the X-ray 12 that has been irradiated from the X-ray tube 150 to the X-ray irradiation region and transmitted through the sample 120 as transmitted X-ray intensity. . The X-ray camera 100 may be of any type as long as the X-ray camera 100 has measurement sensitivity to the X-ray photon energy of the X-ray 12 irradiated from the X-ray tube 150 described in the first embodiment. For example, as the type of the X-ray camera 100, an X-ray flat panel detector, an image intensifier, a CCD camera with an X-ray scintillator, or the like is used.

The control unit 90 includes the position information of the anode 2 by the anode driving unit 3, the rotation angle information of the motor 31 that is the rotation angle information of the anode 2, the position information of the two-dimensional sensor 5, and the measurement value of the X-ray camera 100. The rotation angle information acquired by the sample stage 120 is received, and the material type of the anode material corresponding to the cathode ray irradiation position and the position of the X-ray irradiation region on the sample stage 120 are calculated. Then, the control unit 90 sends a driving signal for irradiating the X-ray irradiation region of the sample stage 120 with the X-ray 12 having a desired X-ray photon energy to the motor 31 of the anode driving unit 3 and the motor of the sample stage 120. 121.
That is, the sample stage 120 moves the sample 110 in accordance with the number of times the characteristic X-rays having different X-ray photon energies are irradiated to the X-ray irradiation region, and moves the X-ray irradiation region to the target position in the sample 110. Let

  FIG. 16 is a control flow diagram of the X-ray inspection apparatus in the present embodiment. The operation state of the X-ray inspection apparatus 200 at the time of dual energy X-ray CT analysis will be described by taking the configuration when the shape of the anode 2 shown in FIGS. 6 and 7 is a truncated cone shape as an example.

  In step S <b> 301 of FIG. 16, the sample 110 is fixed to the sample fixing unit 122 of the sample stage 120.

  Next, in step S <b> 302, a transmission X-ray image “a” is acquired using the X-rays 12 irradiated from the first anode material 22. The rotation speed of the motor 31 for rotating the anode 2 is such that the irradiation position of the cathode line 11 irradiated to the anode 2 while the X-ray camera 100 acquires the transmission X-ray image a is the first anode material 22. To the second anode material 23 or from the second anode material 23 to the first anode material 22. While the X-ray camera 100 captures the transmitted X-ray image a, the motor 121 mounted on the sample stage 120 stops rotating.

  Next, in step S303, the motor 31 rotates to change the type of the anode material that the cathode wire 11 irradiates from the first anode material 22 to the second anode material 23. That is, the cathode ray irradiation position moves from the first anode material 22 to the second anode material 23.

  In step S304, the X-ray camera 100 detects the X-rays 12 irradiated from the second anode material 23 and acquires a transmission X-ray image b. At this time, since the sample 120 does not move, the motor 121 continues to stop.

Next, in step S305, transmission X-rays are obtained using the X-rays 12 corresponding to all of the desired X-ray photon energy at the predetermined rotation angle of the sample 120, that is, all types of materials of the anode material that the anode 2 has. It is determined whether an image has been acquired. In the present embodiment, all desired X-ray photon energies are two types of X-ray photon energies possessed by the X-rays 12 irradiated from the first anode material 22 and the second anode material 23. For this reason, the determination result in step S305 is YES, and the process proceeds to the next step S306. In order to perform dual energy X-ray CT analysis, it is sufficient to change two types of X-ray photon energy of the X-ray 11.
If the determination result in step S305 is NO, the process returns to step S303 to continue the operation.

  Next, in step S306, in order to switch to irradiation of the sample 120 with the X-rays 12 generated from the first anode material 22, the motor 31 is driven to rotate the anode 2. At this time, the motor 121 is rotated by a desired rotation angle, and the sample 120 is rotated with respect to the rotation angle when the transmission X-ray image a and the transmission X-ray image b are captured. The interval between the angles at which the motor 120 is driven to rotate the sample 120 is appropriately 0.5 ° to 1.0 °, but may be any value.

Thereafter, in step S307, it is determined whether all desired transmitted X-ray images have been acquired within the range of the rotation angle of the desired sample 120. If the determination result in step S307 is YES, the process proceeds to step S308. If the determination result in step S307 is NO, the process returns to step S303 to continue the operation.
Specifically, the transmission X-ray image a using the first anode material 22 is acquired until the rotation angle of the motor 121, that is, the sample 120 reaches 180 ° or 360 ° from the initial rotation angle, the second The transmission X-ray image b using the anode material 23 and the rotation of the motor 121 are repeated. By this repetitive operation, a plurality of transmitted X-ray images taken with the X-rays 12 having a plurality of X-ray photon energies can be taken with respect to the interval of the rotation angle of one sample 120.

  That is, in the X-ray inspection method using the X-ray inspection apparatus 200, the first X-ray intensity detection step S302 of detecting the first transmitted X-ray intensity using the X-ray intensity detection unit 100 that is an X-ray camera. Then, after the first X-ray intensity detection step S302, an anode moving step of moving the position of the cathode ray irradiation region in the anode 2 by moving the anode material according to the type of the anode material corresponding to the cathode ray irradiation position. After S303 and anode moving step S303, the second X-ray intensity detecting step S304 for detecting the second transmitted X-ray intensity using the X-ray intensity detecting unit 100 and the second X-ray intensity detecting step S304. After that, the X-ray absorption coefficient is calculated using the X-ray intensity, which is the number of photons of X-rays incident on the sample 120, the first transmitted X-ray intensity, and the second transmitted X-ray intensity, and the sample 120 is calculated. Determine the material of And a determination step S308 that.

  Further, in the X-ray inspection method using the X-ray inspection apparatus 200, after the second X-ray intensity detection step S304, the characteristic X-ray having different X-ray photon energy is applied to the X-ray irradiation region using the sample stage 120. The sample 120 is moved according to the number of times of irradiation, and the sample moving step S306 for moving the X-ray irradiation region to the target position in the sample 120. After the sample moving step S306, the X-ray intensity detector 100 is used. Then, after the third X-ray intensity detecting step S304 for detecting the third transmitted X-ray intensity and the third X-ray intensity detecting step S304, the anode moving step S303 is performed, and the X-ray intensity detecting unit 100 is used. And a fourth X-ray intensity detection step S304 for detecting a fourth transmitted X-ray intensity. Then, in the determination step S308, after the fourth X-ray intensity detection step S304, the X-ray intensity that is the number of photons of the X-rays incident on the sample 120, the first transmitted X-ray intensity, and the second transmitted X-ray. Using the intensity, the third transmitted X-ray intensity, and the fourth transmitted X-ray intensity, the X-ray absorption coefficient is calculated to determine the material of the sample 120.

  Therefore, according to the present embodiment, dual energy X-ray CT analysis can be performed using the X-ray tube 150 shown in the first embodiment. In addition, since dual energy X-ray CT analysis can be performed at a desired angle of the sample 120, the analysis accuracy of the sample 120 can be improved as compared to performing dual energy X-ray CT analysis at the rotation angle of one sample 120. Can do. Note that the image analysis method of the dual energy X-ray CT will not be described in detail here.

FIG. 17 is a configuration diagram of a modification of the X-ray inspection apparatus according to the present embodiment.
The X-ray tube 150a of the modification 200a of the X-ray inspection apparatus shown in FIG. 17 adopts the configuration of the shape of the anode 2b of the second modification that moves linearly (FIGS. 9 and 10). That is, the anode 2b of the second modification is supported by the linear rail guide 25 so as to be movable along the direction in which the first anode material 22 and the second anode material 23 are arranged. The anode 2 b of the second modification can reciprocate linearly along the rail guide 25 by driving the Y-axis drive unit 34 of the anode drive unit 3.

  In the modification 200a of the X-ray inspection apparatus, the positional relationship among the X-ray tube case 6, the X-ray camera 100, the sample 110, and the sample stage 120 is the same as that in FIG. Since the detailed configuration other than the above is the same as the configuration of the first embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and description thereof will not be repeated.

Also when the X-ray tube 150a is used, the rotation timing of the motor 121 is the same as when the rotary anode type X-ray tube 150 shown in FIG. 15 is adopted. That is, the timing of the rotation of the motor 121 should be controlled so as to rotate at the timing at which a desired transmitted X-ray image has been captured and acquired for all of the intended anode materials.
Therefore, as in FIG. 15, dual energy X-ray CT analysis is possible.

DESCRIPTION OF SYMBOLS 1 Cathode, 2, 2 ', 2a, 2b Anode, 3 Anode drive part, 4 Laser light source, 5 Two-dimensional sensor (displacement sensor), 6 X-ray tube case, 7 Power supply, 8 Electromagnetic lens, 11 Cathode line, 12 White X Wire, 21 insulator, 22 first anode material, 23 second anode material, 24 third anode material, 25 rail guide, 31 motor, 32 rotating shaft, 33, 33 ′ X axis drive unit, 34, 34 ′ Y-axis drive unit, 35 Z-axis drive unit, 41 laser light, 42, 42 ′ laser reflected light, 61 X-ray window, 90 control device, 100 X-ray camera, 110 sample, 120 sample stage, 121 motor, 122 sample fixing Department, 150 X-ray tube, 200, 200a X-ray inspection apparatus.

Claims (8)

An anode material of at least two kinds of materials, and an anode in which the anode materials of two kinds of the materials are arranged;
An X-ray tube comprising: a cathode ray that irradiates a cathode ray irradiation region in the anode to generate characteristic X-rays having X-ray photon energy corresponding to the material of the anode material from the cathode ray irradiation region.   The X-ray tube according to claim 1, wherein the anode moves the anode material in a direction in which the anode material of the first type material and the anode material of the second type material are arranged.   The X-ray tube according to claim 1, wherein the cathode moves the cathode ray irradiation region in a direction in which the anode material of the first type material and the anode material of the second type material are arranged. An anode driving unit connected to the anode and moving the anode with respect to the cathode ray irradiation region;
A focus position detector for detecting a shift between the focus position of the cathode ray and the position of the cathode ray irradiation region;
The X-ray tube according to claim 2, wherein the anode driving unit moves the anode in accordance with the shift detected by the focus position detector, and moves the position of the cathode ray irradiation region to the focus position. X-ray tube according to claim 2 or claim 4,
A sample stage for moving the sample with respect to an X-ray irradiation region where the sample is irradiated with X-rays emitted from the X-ray tube;
The sample stage moves the sample in accordance with the number of times the X-ray irradiation region is irradiated with the characteristic X-rays having different X-ray photon energies, and moves the X-ray irradiation region to a target position in the sample. X-ray inspection device to be moved to.   6. An X-ray intensity detection unit that further detects an X-ray intensity, which is the number of photons of X-rays irradiated from the X-ray tube to the X-ray irradiation region and transmitted through the sample, as transmitted X-ray intensity. The X-ray inspection apparatus described. The X-ray inspection apparatus according to claim 6,
A first X-ray intensity detection step of detecting a first transmitted X-ray intensity using the X-ray intensity detector;
After the first X-ray intensity detection step, the anode is moved according to the type of the material of the anode material corresponding to the cathode ray irradiation region, and the anode moving the position of the cathode ray irradiation region in the anode is moved. A moving step;
A second X-ray intensity detection step of detecting a second transmitted X-ray intensity using the X-ray intensity detector after the anode moving step;
After the second X-ray intensity detection step, the X-ray intensity, which is the number of photons of X-rays incident on the sample, the first transmitted X-ray intensity, and the second transmitted X-ray intensity are used. And a determination step of determining an X-ray absorption coefficient to determine the material of the sample. After the second X-ray intensity detection step, the sample stage is moved using the sample stage according to the number of times of irradiation of the X-ray irradiation region with the characteristic X-ray having the different X-ray photon energy. A sample moving step for moving the X-ray irradiation region to a target position in the sample;
A third X-ray intensity detecting step for detecting a third transmitted X-ray intensity using the X-ray intensity detecting unit after the sample moving step;
A fourth X-ray intensity detection step of performing the anode movement step after the third X-ray intensity detection step, and detecting a fourth transmitted X-ray intensity using the X-ray intensity detection unit; Prepared,
In the determination step, after the fourth X-ray intensity detection step, the X-ray intensity that is the number of photons of the X-rays incident on the sample, the first transmitted X-ray intensity, and the second transmitted X-ray The X-ray inspection method according to claim 7, wherein an X-ray absorption coefficient is calculated using the intensity, the third transmitted X-ray intensity, and the fourth transmitted X-ray intensity to determine the material of the sample.

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