JP2005116534A - X ray generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X ray generation apparatus having an air cooling structure and miniaturized size. <P>SOLUTION: The X ray generation apparatus 1 according to the present invention in which a target 14 having the ground potential is adhered to an inner surface of an output window 13 fixed to electrically conductive and thermally conductive output window holding portion 12 provided at the tip of valve 9, and X-ray tube 8 with a cathode 16 for irradiating electron beam toward the target 14 and a power supply portion 21 for driving the X-ray tube 8 are received in a protective case 2, a flange portion 18 formed in the output window holding portion 12 contacts to the electrically conductive and thermally conductive protective case 2 to be fixed to it, and high temperature and electricity continuously generated in X-ray tube 8 are released to outside via the protective case 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an X-ray generator, and more particularly to an X-ray generator in which a small soft X-ray tube is accommodated in a protective case.

  Japanese Patent Publication No. 7-50594 is an example of a conventional X-ray tube. In the X-ray tube disclosed in this publication, when the filament is heated by energization, an electron beam is emitted. This electron beam is accelerated by a focusing grid or the like and collides with the target at a high speed. X-rays specific to the material are emitted. And this X-ray | X_line is discharge | released outside from the X-ray transmissive window provided apart in front of the target. Since this type of X-ray tube becomes hot, its cooling is achieved by natural air cooling from a target ring that is fixed to the target and protrudes from the envelope (valve), thereby maintaining the X-ray generation efficiency and the target. Prevents damage. Further, this type of X-ray tube is housed in a protective case having a power supply unit that generates a voltage of +9.5 kV, and is incorporated in the X-ray generator.

Japanese Patent Publication No. 7-50594

  However, since the conventional X-ray generator is configured as described above, the following problems exist. In other words, the X-ray tube of the type in which the target and the X-ray transmission window are separated from each other has a large envelope itself and is intended for natural air cooling, and therefore requires a large space around the envelope. The protective case was upsized. On the other hand, an ultra-small X-ray tube was developed in which a target and an X-ray transmission window (output window) are integrated. This type of X-ray tube has a small envelope diameter due to its ultra-small size. It is difficult to realize air cooling, and it is difficult to apply an existing protective case.

  In particular, an object of the present invention is to provide an X-ray generator that has an air cooling structure and can be made compact.

  In the X-ray generator according to the present invention, a target having a ground potential is fixed to an inner surface of an output window fixed to a conductive and thermally conductive output window holding portion provided at a tip of a valve, An X-ray generator in which an X-ray tube having a cathode for irradiating an electron beam toward a power source and a power supply unit for driving the X-ray tube are housed in a protective case, and is formed on an output window holding unit The flange portion protruding in the direction is thermally and electrically connected and fixed to a protective case having thermal conductivity.

  In this X-ray generator, since the target is at the ground potential, a negative high potential (for example, -9.5 kV) is supplied to the filament from the power supply unit in the protective case. In this state, the electron beam is irradiated from the cathode, the electron beam collides with the target at the ground potential, X-rays are emitted from the target, and the X-rays are emitted to the outside from the output window. In order to maintain the X-ray generation efficiency and prevent damage to the target, it is necessary to cool a high-temperature target, a valve, or the like. In this case, the high-temperature target is fixed to the output window holding part through the output window, and the valve is also fixed to the output window holding part. Heat the flange to a high temperature. Therefore, since this flange portion is thermally and electrically connected and fixed to a protective case having thermal conductivity, the heat and electricity will escape to the outside through the protective case. It will function as a cooler. As a result, heat generated in the target, the valve, and the like is released to the outside through the protective case, and an optimal air cooling environment is created in the protective case itself. Accordingly, since it is not necessary to create a cooling environment for the X-ray tube inside the protective case, the protective case can be made small, and the X-ray generator can be miniaturized.

  In this case, an X-ray tube housing portion is provided in the power supply case that houses the power supply portion, and the first holding plate formed at the front end of the X-ray tube housing portion and the first holding plate provided at the front end of the protective case It is preferable that the flange portion is sandwiched between the opposing second holding plates. When such a configuration is adopted, the X-ray tube can be easily incorporated into the protective case, so that the assembly efficiency of the X-ray generator is good and the manufacturing cost of the apparatus can be reduced.

  Further, it is preferable that an intermediate member having thermal conductivity is disposed between the first holding plate and the second holding plate, and the flange portion is sandwiched between the first holding plate and the second holding plate via the intermediate member. . When such a configuration is adopted, when the flange portion is sandwiched between the first holding plate and the second holding plate, the intermediate member comes into contact with the second holding plate of the protective case, so that the second holding plate is moved from the flange portion. Thus, the heat transfer path that is transmitted to is substantially expanded, and heat dissipation in the protective case is further promoted.

  The intermediate member is preferably silicon rubber. This silicon rubber has high thermal conductivity and flexibility.

  In addition, it is preferable that the power supply unit and the X-ray tube storage unit that stores the X-ray tube are arranged in parallel, and the valve of the X-ray tube is stored in the X-ray tube storage unit. When such a configuration is adopted, the length of the protective case can be shortened.

  According to the present invention, the air cooling structure can be achieved, and at the same time, the size can be reduced.

  Hereinafter, preferred embodiments of an X-ray generator according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the X-ray generator according to the present embodiment, and FIG. 2 is an exploded perspective view of the X-ray generator. The X-ray generator 1 shown in these drawings has a protective case 2 made of a box type. The protective case 2 is made of a material having high thermal conductivity, for example, aluminum, and is divided into four parts. That is, the protective case 2 is composed of an upper lid 3 having a U-shaped cross section, a lower lid 4 having a U-shaped cross section, a flat front panel 5 and a flat rear panel 6 to form a quadrant box. Yes. Panel support grooves 3a and 3b for inserting the upper ends of the front panel 5 and the rear panel 6 are formed at the front end and the rear end of the upper lid 3, and the front panel 5 and the rear end of the lower lid 4 are formed at the front end and the rear end. Panel support grooves 4a and 4b for inserting the lower end of the back panel 6 are formed.

  Therefore, when assembling the protective case 2, the lower side of the reinforcing plate 29 is screwed to the inner surface of the lower lid 4, and then the lower ends of the front panel 5 and the rear panel 6 are inserted into the panel support grooves 4 a and 4 b of the lower lid 4. The upper cover 3 and the lower cover 4 are aligned so that the upper ends of the front panel 5 and the rear panel 6 are inserted into the panel support grooves 3a and 3b of the upper cover 3 into the panel support grooves 3a and 3b of the upper cover 3, respectively. The upper lid 3 is firmly fixed to the lower lid 4 by screwing the upper side to the inner surface of the upper lid 3. That is, since the protective case 2 has a structure in which the front panel 5 and the rear panel 6 are sandwiched between the upper lid 3 and the lower lid 4, this assembling workability is extremely good.

  In the protective case 2, an X-ray tube 8 that generates soft X-rays and is used for removing static electricity is disposed. As shown in FIG. 3, the X-ray tube 8 has a cylindrical valve 9 made of Kovar glass. A stem 11 having an exhaust pipe 10 is formed at the end of the valve 9, and the valve 9 is opened. A cylindrical Kovar metal output window holding portion 12 is fused and connected to the end. A disk-like output window 13 is fixed to the output window holding portion 12 by Ag brazing so as to close the central opening 12a, and X-rays are generated on the inner surface side of the output window 13 by the collision of an electron beam. A target 14 is deposited.

  Further, two stem pins 15 are fixed to the stem 11, and a filament 16 as a cathode that emits an electron beam at a predetermined voltage is provided in the bulb 9, and this filament 16 is fixed to the tip of the stem pin 15. Has been. Further, a stainless steel focus 17 having a cylindrical shape is fixed to one stem pin 15. Since the output window holding portion 12 is made of Kovar metal, it has thermal conductivity and conductivity, and is electrically connected to the grounded protective case 2 to become the ground potential, and the target 14 is set to the ground potential. ing.

  Therefore, a high potential of −9.5 kV is supplied to the stem pin 15 of the X-ray tube 8 from a power supply unit 21 described later, and an electron beam is irradiated from the filament 16 toward the target 14 having the ground potential. At this time, X-rays are emitted from the target 14 due to the collision of the electron beam, and the X-rays are emitted to the outside from the output window 13. By configuring the X-ray tube 8 in this way, a bulb 9 having a diameter of about 15 mm and a length of about 30 mm is possible, and the X-ray tube 8 has an ultra-compact shape with an overall length of about 40 mm. The target 14 of the ultra-small X-ray tube 8 is at a high temperature, and it is necessary to cool the target 14 in order to maintain the X-ray generation efficiency and prevent damage to the target.

  This cooling measure will be described below. The aforementioned X-ray tube 8 is provided with a flange portion 18 that is integrally formed with the output window holding portion 12 made of Kovar metal and protrudes to the outside. Since the flange portion 18 is in a thermally and electrically conductive state with respect to the target 14, the output window holding portion 12 becomes a high temperature of about 100 ° C. due to the heat continuously generated in the target 14, and the flange portion 18 is It will be heated. Therefore, as shown in FIGS. 1 and 4, the flange portion 18 is fixed in contact with the inner surface of the aluminum front panel 5. The heat of the flange portion 18 can be transmitted to the protective case 2, and the flange portion 18 can be set to the ground potential. In this case, the front panel 5 of the protective case 2 is provided with a circular X-ray irradiation port 5a, and by aligning the output window 13 of the X-ray tube 8 with the X-ray irradiation port 5a, X-ray emission is possible.

  In the protective case 2, a power supply unit 21 including a low voltage generation unit 19 and a high voltage generation unit 20 is accommodated. This power supply unit 21 supplies a high potential of −9.5 kV to the stem pin 15 to drive the X-ray tube 8. First, the low voltage generation unit 19 raises the potential to −1 kV, Next, the high voltage generator 20 raises the potential to -9.5 kV. Such a power supply unit 21 is fixed to a steel power supply case 22, and in this power supply case 22, an X-ray for storing the valve 9 of the X-ray tube 8 is provided separately from a portion for storing the power supply unit 21. A tube housing part 23 is provided. The X-ray tube accommodating portion 23 is provided at a position adjacent to the side of the power source portion 21. As a result, the power supply unit 21 and the X-ray tube housing unit 23 are arranged in parallel, and the length of the protective case 2 is shortened.

  As shown in FIG. 4, the power supply case 22 is provided with a plate-like first holding plate 24 that forms the front end of the X-ray tube housing portion 23 and faces the front panel 5 in parallel. The holding plate 24 is formed with an opening 24 a for inserting the valve 9 of the X-ray tube 8. Therefore, when the bulb 9 of the X-ray tube 8 is inserted into the opening 24a, the flange portion 18 of the X-ray tube 8 is formed between the front surface of the first holding plate 24 and the back surface of the front panel 5 as the second holding plate. It is pinched. In this case, since the power supply case 22 is screwed to the lower cover 4 of the protective case 2, the flange portion 18 of the X-ray tube 8 is supported by the first holding plate 24 of the power supply case 22 and the panel support of the protective case 2. The front panel 5 fixed in the grooves 3a and 4a is firmly sandwiched between the grooves 3a and 4a, and is firmly fixed in the protective case 2.

  Here, an intermediate member 25 having thermal conductivity is provided between the first holding plate 24 and the front panel (second holding plate) 5. The intermediate member 25 has high thermal conductivity and is flexible. Made of silicon rubber. The intermediate member 25 has a shape that substantially fills the space between the first holding plate 24 and the front panel 5, and has an opening 25 a for inserting the valve 9 of the X-ray tube 8. As described above, when the flange portion 18 of the X-ray tube 8 inserted into the opening 25a is sandwiched between the periphery of the opening 24a of the first holding plate 24 and the periphery of the opening 5a of the front panel 5, the intermediate member At the same time as the peripheral edge of the opening 25 a of 25 contacts the flange 18 of the X-ray tube 8, the substantially entire surface of the intermediate member 25 contacts the front panel 5 and the first holding plate 24 of the protective case 2. As a result, the heat transfer path transmitted from the flange portion 18 to the front panel 5 is substantially expanded, and heat dissipation in the protective case 2 made of aluminum is further promoted. Further, since the intermediate member 25 has flexibility, the flange portion 18 can be pressure-bonded to the front panel 5, and the shock absorption property to the X-ray tube 8 is enhanced.

  As shown in FIGS. 1 and 2, an anti-sway member 26 for holding the X-ray tube 8 in the protective case 2 is provided in the X-ray tube housing portion 23, and the anti-sway member 26 is urethane. It consists of resin, and is divided into two so as to sandwich the bulb 9 of the X-ray tube 8 with an arcuate pressing surface 26a. Therefore, each steadying member 26 is brought into contact with the protective plate 29 fixed to the side wall of the protective case 2 and the partition wall 22a in the power supply case 22, and the valve 9 of the X-ray tube 8 is connected to each arc-shaped pressing surface 26a. By sandwiching, the X-ray tube 8 can be securely held in the protective case 2. The X-ray generator 1 has an external lead wire 31 for supplying a predetermined voltage to the low voltage generator 19 of the power supply unit 21. The external lead wire 31 has a rubber cap 30, and the external lead wire 31 is fixed to the protective case 2 by fitting the cap 30 into the opening 6 a of the back panel 6. The high voltage generator 20 is provided with a cathode lead wire 32, and by connecting the lead wire 32 to the stem pin 15 of the X-ray tube 8, a high voltage of −9.5 kV is supplied to the filament 16. Yes.

  Next, an X-ray generator 41 according to the second embodiment will be described. In addition, the same code | symbol is attached | subjected about the structure same or equivalent to the X-ray generator 1 mentioned above, and the description is abbreviate | omitted.

  As shown in FIGS. 5 and 6, the protective case 42 is formed in an elongated shape, and an elongated power supply case 43 is accommodated in the protective case 42. A front portion of the power supply case 43 has an X-ray tube storage portion 44 that stores the X-ray tube 8 and the steadying member 26, and a rear portion of the power supply case 43 has a power supply portion 21. Thus, by arranging the power supply unit 21 and the X-ray tube housing unit 44 in series, the protective case 42 can be elongated, which is effective when the X-ray generator 41 is installed in a narrow place. The other configurations, such as the front panel 5 and the intermediate member 25, are only reduced in size according to the shape of the protective case 42, and their functions and materials are the same as those of the X-ray generator 1 shown in FIG. Is the same.

  The present invention is not limited to the above-described embodiment. For example, as shown in FIG. 7, in the front panel 5, the peripheral portion forming the X-ray irradiation port 5 a has an annular shape that accommodates the flange portion 18. The recess 5b is formed. Therefore, by fitting the flange portion 18 into the recess 5b, the seating property of the flange portion 18 with respect to the front panel 5 is improved, and at the same time, the output window 13 of the X-ray tube 8 and the X-ray irradiation port 5a of the front panel 5 are improved. Positioning becomes easy. Although not shown, the flange portion 18 of the X-ray tube 8 may be fixed with screws or adhesive so as to come into contact with the front panel 5.

It is sectional drawing which shows 1st Embodiment of the X-ray generator which concerns on this invention. It is a disassembled perspective view of the X-ray generator shown in FIG. It is sectional drawing which shows the X-ray tube applied to the X-ray generator of this invention. It is an expanded sectional view which shows the principal part of the X-ray generator shown in FIG. It is sectional drawing which shows 2nd Embodiment of the X-ray generator which concerns on this invention. It is a disassembled perspective view of the X-ray generator shown in FIG. It is an expanded sectional view which shows the principal part of the X-ray generator shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,41 ... X-ray generator, 2,42 ... Protective case, 5 ... Front panel (2nd holding plate), 8 ... X-ray tube, 9 ... Valve, 12 ... Output window holding part, 13 ... Output window, 14 ... Target, 16 ... Filament (cathode), 18 ... Flange part, 21 ... Power supply part, 22, 43 ... Power supply case, 23, 44 ... X-ray tube housing part, 24 ... First holding plate, 25 ... Intermediate member.

Claims (5)

A target that forms a ground potential is fixed to the inner surface of an output window fixed to a conductive and heat conductive output window holding portion provided at the tip of the bulb, and a cathode that irradiates an electron beam toward the target. An X-ray generator in which an X-ray tube and a power supply unit for driving the X-ray tube are housed in a protective case,
An X-ray generation apparatus characterized in that a flange portion formed on the output window holding portion and projecting outward is connected and fixed thermally and electrically to the protective case having thermal conductivity.   An X-ray tube accommodating portion is provided in a power supply case that accommodates the power supply portion, a first holding plate formed at the front end of the X-ray tube accommodating portion, and a first holding plate provided at the front end of the protective case. The X-ray generator according to claim 1, wherein the flange portion is sandwiched by a second holding plate facing each other.   An intermediate member having thermal conductivity is disposed between the first holding plate and the second holding plate, and the flange portion is sandwiched between the first holding plate and the second holding plate via the intermediate member. The X-ray generator according to claim 2, wherein   The X-ray generator according to claim 3, wherein the intermediate member is a silicon rubber.   The X-ray tube accommodating part which accommodates the said power supply part and the said X-ray tube is arrange | positioned in parallel, The valve | bulb of the said X-ray tube is accommodated in the said X-ray tube accommodating part. The X-ray generator as described in any one of Claim 4.

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