JP5221215B2 - X-ray generator - Google Patents

Description

  The present invention relates to an X-ray generator used as an X-ray source in X-ray nondestructive inspection or the like.

As a conventional X-ray generator, Patent Document 1 describes an apparatus that focuses an electron beam emitted from an electron gun onto a target using an electromagnetic coil and emits X-rays from the target.
Japanese Patent No. 3999399

  By the way, if an electron beam continues to be incident on a certain portion of the target, the portion deteriorates and the X-ray conversion efficiency is lowered. Therefore, the X-ray generator has a configuration that can change the incident position of the electron beam on the target. It is desirable to adopt.

  However, in the X-ray generator described in Patent Document 1, the incident position of the electron beam with respect to the target is changed by loosening or removing the fixing ring for fixing the target to the emission end of the electron passage. Each time, the vacuum state in the electron passage may be broken.

  Therefore, the present invention has been made in view of such circumstances, and provides an X-ray generator capable of changing the incident position of an electron beam on a target while maintaining a vacuum state in an electron passage. With the goal.

In order to achieve the above object, an X-ray generator according to the present invention is an X-ray generator that causes an electron beam emitted from an electron gun to enter a target and emit X-rays from the target. An electron path through which an electron beam emitted from the beam passes, a support member that supports the target, a pressing member that presses the support member against the emission end of the electron path, and an electron path that surrounds the electron path A hermetic sealing member disposed between the emission end and the support member, and a first provided between the emission end and the support member so as to surround the hermetic sealing member at the emission end. And a resin layer.

  In this X-ray generator, since the first resin layer is provided between the support member that supports the target and the emission end of the electron path, the support member moves so as to slide on the first resin layer. By doing so, the support member can be slid in a state where the support member is pressed against the emission end by the pressing member. At this time, the airtightness between the support member and the emission end portion is ensured by an airtight sealing member disposed between the emission end portion and the support member so as to surround the electron path at the emission end portion. . Therefore, according to the X-ray generator, it is possible to change the incident position of the electron beam on the target while maintaining the vacuum state in the electron passage.

  In the X-ray generator according to the present invention, it is preferable that the pressing member is made of a resin, or a second resin layer is provided between the support member and the pressing member. In these cases, the support member can be slid more smoothly.

  Note that the first resin layer and the second resin layer are preferably resin sheets. Replacement is possible when it is worn away by sliding of the support member or deteriorated due to heat generation or X-ray irradiation.

  In the X-ray generator according to the present invention, the support member is provided with a holding frame for holding the target inside, and the pressing member is rotatably fitted with the holding frame and is eccentric from the center line of the electron path. A fitting hole having a center line is preferably provided. In this case, the incident position of the electron beam with respect to the target can be easily and reliably changed by rotating the holding frame of the support member fitted in the fitting hole of the pressing member.

  In the X-ray generator according to the present invention, the first resin layer is preferably provided with an insertion hole through which a target current detection terminal that contacts the support member is inserted. In this case, the target current can be accurately detected even if the first resin layer is interposed between the support member that supports the target and the emission end of the electron passage.

  According to the present invention, it is possible to change the incident position of the electron beam with respect to the target while maintaining the vacuum state in the electron passage.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted.
[First Embodiment]

  FIG. 1 is a cross-sectional view of the X-ray generator of the first embodiment. As shown in FIG. 1, the X-ray generator 1 makes an electron beam E emitted from a filament F of an electron gun 2 incident on a target 5 of a target unit T and moves forward from the target 5 (advancing of the electron beam E). The front side of the direction is “front” and the rear side is “rear”). The X-ray generator 1 is a device called an open type in which the filament F and the target unit T can be exchanged, and has a cylindrical main body 3 that houses the electron gun 2 and a hinge at the front end of the main body 3. And a cylindrical opening 6 that is tiltably connected via the portion 4. In the X-ray generator 1, the front end portion of the main body portion 3 can be opened and the filament F can be exchanged by laying down the opening portion 6 via the hinge portion 4.

  The open portion 6 includes a double cylindrical portion 8 including an inner cylindrical portion 8a and an outer cylindrical portion 8b that are integrally connected at a rear end portion, and a truncated cone fixed to a front end portion of the outer cylindrical portion 8b by a fixing screw 14. And an emission end portion 13 having a shape. A stainless steel pipe member 9 extending in the traveling direction of the electron beam E is inserted in the inner cylinder portion 8a, and an aluminum bobbin is provided between the inner cylinder portion 8a and the outer cylinder portion 8b. An electromagnetic coil 12 formed by winding an enamel wire around 11 is arranged. The double cylindrical portion 8 and the emission end portion 13 are made of a magnetic material such as soft iron and constitute a part of a magnetic circuit through which a magnetic flux generated by the electromagnetic coil 12 passes.

  The electron beam E emitted from the electron gun 2 travels in the pipe member 9 through the rear end portion of the pipe member 9 opened in the main body portion 3. That is, the pipe member 9 constitutes a part of the electron passage 7 through which the electron beam E emitted from the electron gun 2 passes, and the center line L1 of the electron passage 7 is the center line. The electromagnetic coil 12 focuses the electron beam E passing through the electron path 7 on the target 5.

  FIG. 2 is a cross-sectional view of a main part of the X-ray generator shown in FIG. As shown in FIG. 2, a stainless steel aperture member 17 is arranged inside the emission end portion 13. The aperture member 17 includes a bottomed cylindrical main body portion 15 that opens to the front side, and a disc-shaped flange portion 16 that is integrally formed with the front end portion of the main body portion 15. The main body portion 15 is inserted into the front end portion of the pipe member 9, and the flange portion 16 is fixed to the emission end portion 13 with a fixing screw 22.

  The bottom portion of the main body portion 15 includes an aperture portion 19 provided with an electron passage hole 18 for narrowing the electron beam E. The electron passage hole 18 has the center line L1 of the electron passage 7 as a center line, and the inner wall surface 18a of the electron passage hole 18 is an uneven surface by forming threads and screw grooves. Here, since the inner wall surface 9 a of the pipe member 9 is smooth, the inner wall surface 18 a of the electron passage hole 18 of the main body portion 15 is the inner wall surface of the pipe member 9 positioned on the electron gun 2 side with respect to the main body portion 15. The surface is rougher than that.

  A bottomed cylindrical aperture member 21 that opens to the rear side is inserted into the main body portion 15. The bottom portion of the aperture member 21 includes an aperture portion 24 provided with an electron passage hole 23 for narrowing the electron beam E. The aperture portion 24 is inserted into the emission hole 13 a of the emission end portion 13. The electron passage hole 23 and the emission hole 13a have the center line L1 of the electron passage 7 as the center line.

  As described above, in the X-ray generator 1, the electron passage 7 is configured by the pipe member 9, the main body portion 15, the aperture member 21, and the emission end portion 13. The electromagnetic coil 12 focuses the electron beam E passing through the electron path 7 onto the target 5, but the lens center of the electromagnetic coil 12 is located on the center line L <b> 1 between the aperture portion 19 and the aperture portion 24. . Therefore, the aperture part 19 cuts the peripheral part of the diverging electron beam E to narrow the electron beam E, and the aperture part 24 cuts the peripheral part of the focused electron beam E to narrow the electron beam E. .

  A resin sheet (first resin layer) 25 provided with an opening 25a facing the electron path 7 at the emission end 13 (that is, facing the emission hole 13a) is disposed on the front surface 13b of the emission end 13. The target unit T is disposed on the front surface of the resin sheet 25. The resin sheet 25 is made of an electrically insulating resin material (for example, polyimide). The target unit T includes a circular thin plate-shaped support member 26 that supports the target 5, and the rear surface of the support member 26 is in contact with the front surface of the resin sheet 25. The support member 26 is made of stainless steel, and a holding frame 27 having a circular outer shape is integrally formed on the support member 26. A beryllium X-ray emitting plate 28 is fixed to the holding frame 27, and a tungsten target 5 is formed on the rear surface of the X-ray emitting plate 28. The holding frame 27 holds the target 5 on the inner side so as to face the emission hole 13 a through the opening 25 a of the resin sheet 25.

  The support member 26 is pressed against the emission end 13 by a cap-shaped pressing member 29 made of an electrically insulating resin. Between the emission end portion 13 and the support member 26, it is located inside the opening 25 a of the resin sheet 25 and surrounds the electron passage 7 at the emission end portion 13 (that is, surrounds the emission hole 13 a). In addition, an O-ring 31 is disposed as an airtight sealing member for maintaining a vacuum. In the pressing member 29, the holding frame 27 of the supporting member 26 is fitted into the fitting hole 29a, and the O-ring 31 is pressed and the rear surface of the supporting member 26 is in contact with the front surface of the resin sheet 25. At the same time, it is fixed to the emission end 13 by a fixing screw 33 (see FIG. 3). In the X-ray generator 1, the target unit T can be exchanged by removing the pressing member 29. Since the fixing screw 33 does not protrude forward from the front surface of the pressing member 29, the X-ray irradiated object can be brought closer to the X-ray emitting plate 28. Further, the positioning groove of the O-ring 31 is not limited to the rear surface of the support member 26, and may be provided on the front surface of the emission end portion 13.

  A target current detection terminal 32 is attached to the emission end 13 and the flange portion 16 of the aperture member 17, and the target current detection terminal is in contact with the rear surface of the support member 26 of the target unit T on the resin sheet 25. An insertion hole 25 b through which 32 is inserted is provided. When the X-ray generator 1 is in operation, it is necessary to evacuate the space through which the electron beam E passes, such as the electron passage 7, so that as shown in FIGS. An O-ring 41 as an airtight sealing member is disposed between the open portion 6, between the aperture member 17 and the pipe member 9, between the aperture member 17 and the emission end portion 13, and the like.

  FIG. 3 is an exploded perspective view of a main part of the X-ray generator shown in FIG. As shown in FIG. 3, the fitting hole 29 a provided in the pressing member 29 has a center line L 2 that is eccentric from the center line L 1 of the electron path 7. The holding frame 27 that holds the target 5 on the inner side is rotatably fitted in the fitting hole 29 a of the pressing member 29. Therefore, the incident position P of the electron beam E with respect to the target 5 deviates from the rotation center C of the target 5.

  In the X-ray generator 1 configured as described above, the electron beam E is emitted from the filament F of the electron gun 2 while evacuating the space where the electron beam E passes, such as the electron passage 7. The The emitted electron beam E is focused on the target 5 of the target unit T by the electromagnetic coil 12 while passing through the electron path 7. As a result, X-rays are emitted forward from the focused spot of the electron beam E on the target 5.

  By the way, in the X-ray generator 1, while the resin sheet 25 is arrange | positioned between the support member 26 which supports the target 5, and the radiation | emission end part 13 of the electronic passage 7, fitting of the press member 29 which consists of resin is carried out The holding frame 27 of the support member 26 is rotatably fitted in the hole 29a. That is, since the support member 26 is in a state where both surfaces thereof are sandwiched between the resin layers, even when the support member 26 is pressed against the emission end portion 13 by the pressing member 29, the fitting hole of the pressing member 29 is provided. The support member 26 can be smoothly slid and rotated so as to slide between the support member 26 and the resin sheet 25 around the center line L2 of 29a. At this time, since the incident position P of the electron beam E with respect to the target 5 deviates from the rotation center C of the target 5, the incident position of the electron beam E with respect to the target 5 is changed. In addition, the airtightness between the support member 26 and the emission end 13 is such that the O-ring 31 disposed so as to surround the electron path 7 at the emission end 13 and the opening facing the electron path 7 at the emission end 13. It is ensured by the resin sheet 25 provided with. Therefore, according to the X-ray generator 1, it is possible to change the incident position P of the electron beam E with respect to the target 5 while maintaining the vacuum state in the electron passage 7.

  In order to facilitate the rotation of the support member 26, the support member 26 is preferably provided with a locking portion. For example, as shown in FIG. 4, the holding frame 27 of the support member 26 is provided with an insertion hole 27 a as a locking portion, and the pair of insertion pins 51 of the jig 50 is inserted into the insertion hole 27 a to rotate the jig 50. By doing so, the support member 26 is rotated. Thus, by rotating the holding frame 27 of the support member 26 fitted in the fitting hole 29a of the pressing member 29, the incident position P of the electron beam E with respect to the target 5 can be easily and reliably changed. It becomes. The locking portion for rotating the support member 26 may be a protrusion instead of a hole like the insertion hole 27a, but the X-ray irradiated object is desired to be closer to the X-ray emitting plate 28. For this, a hole shape is preferred.

Further, the support member 26 that supports the target 5 is electrically insulated from the emission end portion 13 by being sandwiched between the resin sheet 25 and the resin pressing member 29, and the support member 26 is disposed on the resin sheet 25. An insertion hole 25b is provided through which the target current detection terminal 32 that comes into contact with is inserted. Therefore, the target current can be accurately detected without being affected by electrical fluctuations at the emission end 13.
[Second Embodiment]

  FIG. 5 is a cross-sectional view of main parts of the X-ray generator of the second embodiment, and FIG. 6 is an exploded perspective view of main parts of the X-ray generator shown in FIG. As shown in FIGS. 5 and 6, the X-ray generator 1 of the second embodiment is that a resin sheet (second resin layer) 34 is disposed between the support member 26 and the pressing member 29. This is different from the X-ray generator 1 of the first embodiment described above. The resin sheet 34 is formed in an annular shape from an electrically insulating resin material (for example, polyimide), a main body 34 a interposed between the front surface of the support member 26 and the rear surface of the pressing member 29, and a holding frame 27, and a standing portion 34b interposed between the side surface of the fitting hole 29a and the side surface of the fitting hole 29a.

  According to the X-ray generator 1 configured as described above, even if the pressing member 29 is made of metal, the support member 26 can be sandwiched between the resin layers, so that the electrical insulation of the support member 26 is ensured and the target is secured. The current can be accurately detected, and the support member 26 can be slid smoothly when the incident position P of the electron beam E with respect to the target 5 is changed.

  The present invention is not limited to the embodiment described above.

  For example, as shown in FIG. 7, the fitting hole 29 a of the pressing member 29 is formed larger than the holding frame 27 of the supporting member 26, thereby supporting in a plane substantially orthogonal to the center line L <b> 1 of the electron path 7. The member 26 may be slid. Also in this case, the incident position P of the electron beam E with respect to the target 5 can be changed while the vacuum state in the electron passage 7 is maintained.

  Furthermore, the X-ray generator 1 is not limited to a single-coil structure, but may have a two-stage coil structure. Further, the material of the resin sheet is not limited to polyimide, and other materials may be used as long as they are electrically insulating and have high durability against X-rays. For example, polysulfone, polyether ether ketone, polyphenylene sulfide and the like may be used. Further, instead of the resin sheet, a resin film may be formed by vapor deposition or application, for example, a resin layer may be formed by vapor deposition of polyimide.

It is sectional drawing of the X-ray generator of 1st Embodiment. It is principal part sectional drawing of the X-ray generator shown by FIG. It is a principal part disassembled perspective view of the X-ray generator shown by FIG. It is a principal part perspective view of the X-ray generator shown by FIG. It is principal part sectional drawing of the X-ray generator of 2nd Embodiment. It is a principal part disassembled perspective view of the X-ray generator shown by FIG. It is a principal part perspective view of the X-ray generator of other embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... X-ray generator, 2 ... Electron gun, 5 ... Target, 7 ... Electron passage, 12 ... Electromagnetic coil, 13 ... Output end part, 25 ... Resin sheet (1st resin layer), 25a ... Opening, 25b ... Insertion hole, 26 ... support member, 27 ... holding frame, 29 ... pressing member, 29a ... fitting hole, 31 ... O-ring (airtight sealing member), 32 ... target current detection terminal, 34 ... resin sheet (second) Resin layer), E ... electron beam, L1, L2 ... centerline.

Claims (7)

An X-ray generator for causing an electron beam emitted from an electron gun to enter a target and emitting X-rays from the target,
An electron path through which the electron beam emitted from the electron gun passes;
A support member for supporting the target;
A pressing member that presses the support member against the emission end of the electron path;
An airtight sealing member disposed between the emission end and the support member so as to surround the electron passage at the emission end;
An X-ray generation apparatus comprising: a first resin layer provided between the emission end and the support member so as to surround the hermetic sealing member at the emission end.   The X-ray generator according to claim 1, wherein the first resin layer is a resin sheet disposed between the emission end portion and the support member.   The X-ray generator according to claim 1, wherein the pressing member is made of resin.   The X-ray generator according to claim 1, wherein a second resin layer is provided between the support member and the pressing member.   The X-ray generator according to claim 4, wherein the second resin layer is a resin sheet disposed between the support member and the pressing member. The support member is provided with a holding frame for holding the target inside,
6. The pressing member according to claim 1, wherein the holding frame is rotatably fitted, and a fitting hole having a center line eccentric from the center line of the electron passage is provided. The X-ray generator according to one item.   The X-ray generator according to any one of claims 1 to 6, wherein the first resin layer is provided with an insertion hole through which a target current detection terminal that contacts the support member is inserted. .

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