JP2015173045A - Radiation tube, and radiation generator and radiography system using the radiation tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation tube in which, even when temperature is increased in manufacture and use thereof, thermal stress generated due to the physical property difference between a NEG and a member to which the NEG is attached is relaxed, and thereby peeling and chipping of the NEG can be prevented.SOLUTION: When a NEG 8 is attached on an inner surface of one of an insulation tube 2, a cathode 3 and an anode 4, an attachment surface on which the NEG 8 is attached is a rough surface having a maximum height roughness Rz of 0.1 μm or more and 500 μm and or less.

Description

  The present invention relates to a radiation tube applied to diagnostic applications in the field of medical equipment and non-destructive radiography in the field of industrial equipment, a radiation generator using the radiation tube, and a radiation imaging system.

  In a radiation generating apparatus, it is required to improve durability and improve maintenance. One of the main factors that determine the durability of the radiation generator is a decrease in the internal atmosphere of the radiation tube. As a method for maintaining the degree of vacuum in the radiation tube container, a method of providing a non-evaporable getter (NEG) in the container is known. NEG is activated by heating in a vacuum atmosphere, and expresses the action of exhausting the gas present in the container. NEG is a preferred form of getter in the downsizing of a radiation tube in that it does not require a special configuration for preventing getter material from being scattered and deposited in an unnecessary range unlike an evaporation type getter. Patent Document 1 discloses an NEG that is used by being activated by heating after being fixed to a member constituting an anode of a radiation tube or a base member of a cathode.

US Pat. No. 6,134,300

  However, when a thermal cycle such as a high temperature during the production or use of the radiation tube is applied, peeling at the interface between the NEG and the member to which the NEG is attached or chipping (chip) of the NEG may occur. there were. This is due to thermal stress caused by physical properties such as the coefficient of thermal expansion between the NEG and the member. Such peeling or chipping of the NEG may affect radiation generation as a contaminant in the radiation tube.

  An object of the present invention is to alleviate a thermal stress generated due to a difference in physical properties between NEG and a member to which the NEG is attached even when the radiation tube is heated at the time of production or use. The purpose is to prevent peeling and chipping of NEG due to thermal stress. Another object of the present invention is to provide a highly reliable radiation generating apparatus and radiation imaging system using the radiation tube.

A first aspect of the present invention includes an envelope including a tubular insulating tube, a cathode attached to one end of the insulating tube, and an anode attached to the other end of the insulating tube, A radiation tube with a non-evaporable getter attached inside,
The non-evaporable getter is fixed to a mounting surface having a maximum height roughness Rz of 0.1 μm or more and 500 μm or less.

A second aspect of the present invention is a radiation generating tube,
A storage container that contains the radiation generating tube and has a radiation emission window for taking out radiation generated from the radiation generating tube;
The radiation generator is characterized in that an extra space inside the storage container is filled with an insulating fluid.

A third aspect of the present invention is a radiation generator,
A radiation imaging system comprising: a radiation detection device that detects radiation emitted from the radiation generation tube and transmitted through a subject; and a control device that controls the radiation generation device and the radiation detection device in a coordinated manner. is there.

  According to the present invention, the mounting surface to which the NEG is attached is roughened, so that even when thermal stress is generated, the thermal stress is relaxed and the peeling or chipping of the NEG is suppressed. Further, when an adhesive is used for attaching the NEG, the thermal conductivity from the attachment surface to the NEG is improved, and the activation of the NEG by heating can be performed efficiently. Therefore, according to the present invention, a highly reliable radiation tube, and a highly reliable radiation generating apparatus and radiation imaging system using the radiation tube are provided.

It is sectional drawing of the direction along the tube axis | shaft of an insulating tube which shows typically the structure of one Embodiment of the radiation tube of this invention. It is sectional drawing of the direction along the tube axis | shaft of an insulating tube which shows typically the structure of preferable one Embodiment of the radiation generator using the radiation tube of FIG. It is a block diagram which shows the structure of the radiography system using the radiation generator of FIG. It is sectional drawing of the thickness direction of a cathode which shows the attachment form of NEG in the radiation tube of this invention. It is a block diagram which shows the structure of the evaluation system which evaluates the output stability of a radiation generator.

  A characteristic feature of the radiation tube of the present invention is that a surface on which a non-evaporable getter (NEG) is attached is a rough surface. The present invention will be described in detail below with reference to preferred embodiments. FIG. 1 is a diagram showing the configuration of a preferred embodiment of the radiation tube of the present invention, and is a cross-sectional view in the direction along the tube axis of the insulating tube. FIG. 2 is a diagram showing a configuration of a preferred embodiment of a radiation generator using the radiation tube of FIG. 1, and is a cross-sectional view in a direction along the tube axis of the insulating tube. Further, FIG. 3 is a block diagram showing a configuration of a radiation imaging system using the radiation generator of FIG.

<Radiation tube>
As shown in FIG. 1, a radiation tube 1 of the present invention is an envelope comprising a tubular insulating tube 2, a cathode 3 attached to one end of the insulating tube 2, and an anode 4 attached to the other end. The NEG 8 is attached to the inner side of the envelope, in the present embodiment, the inner surface of the cathode 3. An electron emission source 5 is connected to the cathode 3, and a target 7 is connected to the anode 4. The cathode 3 and the anode 4 are disposed so as to face each other with the insulating tube 2 interposed therebetween, and brazing, welding, an adhesive or the like is used for fixing the insulating tube 2, the cathode 3 and the anode 4. In this embodiment, the transmission type radiation tube is exemplified, but the present invention is preferably applied to a reflection type radiation tube.

  The insulating tube 2 is made of glass, ceramics, etc. having a cylindrical shape and strength and insulation. For the cathode 3 and the anode 4, a metal that can be easily bonded to the insulating tube 2 is used. For example, copper, aluminum or an alloy Kovar may be used. The insulating tube 2 is preferably a circular tube, but is not particularly limited in the present invention. Examples of materials for the anode 3 and the cathode 4 include kovar, steel, alloy steel, SUS material, metals such as Au, Ag, Cu, Ti, Mn, Mo, and Ni, and alloys thereof.

  The electron emission mechanism of the electron emission source 5 may be any electron source that can control the amount of electron emission from the outside of the radiation tube 1. For example, a hot cathode such as a tungsten filament or an impregnated cathode, or a cold cathode such as a carbon nanotube. A cathode can be used. The electron emission source 5 can include a grid electrode (not shown) and an electrostatic lens electrode for the purpose of controlling the beam diameter, electron current density, on / off timing, and the like of the electron beam 9.

  In the present embodiment, the target 7 is provided with a target layer 7b that emits radiation by irradiation of the electron beam 9 inside the radiation-transmissive support substrate 7a, that is, on the electron emission source 5 side. The target layer 7b contains a high atomic number, high melting point, high specific gravity metal element tantalum, molybdenum, tungsten, or the like as a target metal. The support substrate 7a is preferably made of a material having high radiation transparency and good thermal conductivity. For example, diamond, silicon nitride, silicon carbide, aluminum nitride, graphite, beryllium, or the like can be used. In particular, diamond is preferable because it has extremely high thermal conductivity and high radiation transparency compared to other materials.

  The electron beam 9 emitted from the electron emission source 5 is accelerated by a voltage applied between the cathode 3 and the anode 4 from a high voltage power source (not shown), collides with the target 7 attached to the anode 4, and the target layer Radiation 10 is emitted from 7b. Incidentally, the electrons contained in the electron beam 9 reach the incident energy required for generating radiation in the target layer 7b by the acceleration electric field formed in the internal space of the radiation tube 1 sandwiched between the cathode 3 and the anode 4. Accelerated.

  In the present embodiment, the target 7 is attached to the shielding member 6. The shielding member 6 is a member that surrounds the outer periphery of the support substrate 7a of the target 7 and protrudes toward the radiation emitting side (outside the radiation tube 1). That is, the shielding member 6 has a passage opened at both ends, and the target 7 is installed at the end of the passage on the electron emission source 5 side or in the middle. The passage of the shielding member 6 is a passage for guiding the electron beam 9 to the electron beam irradiation region of the target layer 7b on the electron emission source 5 side with respect to the target 7, and the opposite side is the radiation 10 outside the radiation tube 1. It becomes a passage for guiding.

  The shielding member 6 is a member that shields radiation, and unnecessary radiation out of the radiation emitted from the target layer 7b is shielded by the shielding member 6, and only the necessary radiation 10 passes through the passage described above, and then the radiation tube 1 Will be released to the outside. The shielding member 6 also has a function as a heat radiator. Heat generated by irradiating the target 7 with the electron beam 9 is radiated to the outside through the shielding member 6. The material constituting the shielding member 6 preferably has a high radiation absorption rate from the viewpoint of a radiation shielding member, and preferably has a high thermal conductivity from the viewpoint of a radiator. For example, a metal material such as tantalum or molybdenum can be used. Moreover, it is also possible to comprise a combination of these materials having a high radiation absorption rate and materials having a higher thermal conductivity (for example, copper or aluminum).

  The potential of the target 7 is set by the shielding member 6 or by the anode 4 through the shielding member 6. Therefore, in the present invention, it can be said that the shielding member 6 is also a part of the anode 4. Accordingly, the shielding member 6 is also included in the anode 4 as a member for attaching the NEG 8 in the present invention.

The internal space of the radiation tube 1 is evacuated for the purpose of ensuring the mean free path of the electron beam 9. The degree of vacuum inside the radiation tube 1 is preferably 1 × 10 ⁻⁴ Pa or less, and more preferably 1 × 10 ⁻⁶ Pa or less from the viewpoint of the lifetime of the electron emission source 5.

  The internal space of the radiation tube 1 can be evacuated by sealing the exhaust pipe after evacuation using an exhaust pipe (not shown) and a vacuum pump. In the present invention, the NEG 8 is arranged in the internal space of the radiation tube 1 for the purpose of maintaining the degree of vacuum. In the present invention, the attachment surface of the member to which the NEG 8 is attached is a rough surface having a maximum height roughness Rz (JIS B0601 '2001) of 0.1 μm or more and 500 μm or less. In the embodiment of FIG. 1, since the NEG 8 is attached to the inner surface of the cathode 3, the attachment surface is an area of the inner surface of the cathode 3 where at least the NEG 8 is attached.

  As a method for attaching the NEG 8 according to the present invention, there are a method for directly attaching the NEG 8 to the inner surface of the envelope with an adhesive and a method using a fixing member. A specific example is shown in FIG. FIGS. 4A to 4F show examples in which the NEG 8 is attached to the cathode 3, and are schematic cross-sectional views in the thickness direction of the cathode 3. 4A shows an example in which NEG 8 is attached to the inner surface of cathode 3 via adhesive 41, and FIG. 4B shows adhesive 41 on the outer periphery of the end of NEG 8 on the inner surface side of cathode 3. As shown in FIG. This is an example in which the NEG 8 is fixed to the cathode 3, and FIG. 4 (c) is a combination of (a) and (b). 4D shows an example in which NEG 8 is fixed to the fixing member 42 via the adhesive 41, and the fixing member 42 is attached to the cathode 3. FIG. 4E is attached to the cathode 3. In this example, the NEG 8 is pressed and fixed by the fixing member 42. FIG. 4F shows an example in which the NEG 8 is fitted and fixed to a fixing member 42 made of an elastic member, and the fixing member 42 is attached to the cathode 3. 4A to 4C and 4E, the mounting surface of the NEG 8 is the inner surface of the cathode 3, and in FIGS. 4D and 4F, the mounting surface of the NEG 8 faces the NEG 8 of the fixing member 42. Surface.

  In the present invention, by making the mounting surface of the NEG 8 rough, the heating process for activating the NEG 8 and the thermal stress generated in the high temperature state when the radiation tube 1 is used are alleviated. As shown in FIGS. 4A, 4C, and 4D, when the NEG 8 is attached to the attachment surface via the adhesive 41, the attachment surface is a rough surface, so that it is bonded compared to the smooth surface. The thermal stress is locally dispersed and relaxed by the elasticity of the agent 41. Also, as shown in FIGS. 4B, 4E, and 4F, when the NEG 8 is in direct contact with the mounting surface, the mounting surface is rough, so that the NEG 8 and the mounting surface are compared to the smooth surface. The NEG 8 is slippery with respect to the mounting surface, and the thermal stress is relieved. Therefore, peeling and chipping of NEG 8 due to thermal stress are suppressed.

  Further, as shown in FIGS. 4A, 4C, and 4D, when the NEG 8 is attached to the attachment surface via the adhesive 41, the attachment surface is a rough surface, so that it is more smooth than the smooth surface. The contact area with the adhesive 41 increases. Therefore, in the step of activating the NEG 8 by heating from the outside of the radiation tube 1, the thermal conductivity from the cathode 3 to the NEG 8 is improved, and the effect that the NEG 8 can be efficiently heated by heating efficiently is also obtained.

  In the present invention, the degree of the rough surface of the mounting surface to which the NEG 8 is mounted is 0.1 μm or more and 500 μm or less, preferably 0.8 μm or more and 100 μm or less, with the maximum height roughness Rz (JIS B0601 '2001). . If the maximum height roughness is less than 0.1 μm, it is difficult to obtain a thermal stress relaxation effect, which is not preferable. When the maximum height roughness exceeds 500 μm, the gap between the mounting surface and the NEG 8 is widened, and the thermal conductivity from the mounting surface to the NEG 8 when the NEG 8 is activated by heating in the mounting mode without the adhesive 41. Decreases, which is not preferable. Further, even in the form through the adhesive 41, if the maximum height roughness exceeds 500 μm, the thickness of the adhesive layer increases, and the thermal conductivity in the thickness direction decreases, which is not preferable. As a rough surface processing method for the attachment surface, cutting using a milling machine or the like can be used. Further, when forming a rough surface of several μm or less, polishing processing or the like may be performed.

  The NEG 8 used in the present invention is porous and has a rough surface for improving the exhaust performance. Specifically, it is a sintered type getter or a sintered type porous getter, and the maximum height roughness Rz is 1 μm to 80 μm. Since the NEG 8 is connected to protrude toward the inside of the envelope, the gas released in the radiation tube 1 can be efficiently adsorbed and exhausted, and the atmosphere in the tube can be maintained at a high vacuum. As described above, the NEG 8 is attached to any one of the insulating tube 2, the cathode 3, the anode 4, and the shielding member 6 constituting the envelope, but may be two or more. Since NEG 8 is activated by heating from the outside, it is preferably attached at a position where it can be easily heated from the outside.

  The adhesive 41 used in FIGS. 4A to 4D preferably has a high thermal conductivity in order to efficiently transmit heat from the outside to the NEG. Therefore, the adhesive preferably contains a heat conductive material, and the heat conductive material is at least one selected from the group of silver, copper, gold, diamond, aluminum, silicon carbide, aluminum nitride, and graphite. It is preferable that The heat conductivity as an adhesive is preferably higher from the point of heat conduction, but practically, it preferably has a heat conductivity of 0.5 W / (m · K) or more.

  As the fixing member 42 used in FIGS. 4D, 4E, and 4F, it is preferable that the thermal conductivity is higher. In particular, in the case of FIGS. 4E and 4F, an elastic member is preferable, and it is formed into a leaf spring or a disc spring and used. Specific examples include SUS304 (thermal conductivity: 16.3 W / (m · K)), copper (thermal conductivity: 398 W / (m · K)), and copper alloys. A member having high heat resistance is also preferable in that the degree of freedom in heating temperature in activation of NEG8 is high. Specifically, Inconel (registered trademark) X-750 (thermal conductivity: 12 W / (m · K), heat resistance: 450 ° C.), silicon nitride (thermal conductivity: 27 W / (m · K), heat resistance : 1000 ° C.). In FIG. 4D, an inelastic member is also preferably used. Specifically, the above SUS304, copper and copper alloy, and silicon nitride can be used as a plate material. Further, Kovar (thermal conductivity: 17 W / (m · K)), zirconia (thermal conductivity: 2 W / (m · K)), alumina (thermal conductivity: 30 W / (m · K)), and the like are also used. . Furthermore, aluminum nitride (thermal conductivity: 150 W / (m · K)) and silicon carbide (thermal conductivity: 60 W / (m · K)) have high thermal conductivity and are preferably used.

  4D and 4F, the NEG 8 can be attached to the fixing member 42 and the fixing member 42 can be attached to the inner surface of the cathode 3 by welding or the like, and the number of processes is increased as compared with the case where the NEG 8 is directly attached to the cathode 3. However, workability is good. 4D to 4F are preferable because the inside of the radiation tube 1 is not exposed to the solvent component of the adhesive 41 or the like.

<Radiation generator>
Next, the radiation generator of this invention is demonstrated using FIG. FIG. 2 is a cross-sectional view of an embodiment of a radiation generator using the radiation tube 1 of FIG. The radiation generating apparatus 11 of the present invention includes a radiation generating tube 1 and a storage container 12 that contains the radiation generating tube 1 and has a radiation emission window 14 for taking out radiation generated from the radiation generating tube 1. The excess space inside the storage container 12 is filled with the insulating fluid 15. In addition, the radiation generator 11 may have a drive circuit 13 for driving the radiation tube 1 in the storage container 12.

  The drive circuit 13 applies a tube voltage Va between the cathode and the anode, and an acceleration electric field is formed between the target and the electron emission source. The radiation line type can be selected by appropriately setting the tube voltage Va corresponding to the layer thickness of the target layer and the metal type.

  The storage container 12 that stores the radiation tube 1 and the drive circuit 13 is preferably a container having sufficient strength as a container and excellent in heat dissipation, and as its constituent material, for example, a metal material such as brass, iron, stainless steel, or the like Is used. The insulating fluid 15 is an electrically insulating fluid, preferably a liquid, and has a role of maintaining electrical insulation inside the storage container 12 and a role as a cooling medium for the radiation tube 1. As the insulating liquid, it is preferable to use an electric insulating oil such as mineral oil, silicone oil or perfluoro oil.

<Radiation imaging system>
Next, the radiation imaging system of the present invention will be described with reference to FIG. The radiation imaging system of FIG. 3 is an embodiment using the radiation generator of FIG. The radiation imaging system of the present invention includes a radiation generation apparatus 11 of the present invention, a radiation detection apparatus 21 that detects radiation emitted from the radiation generation tube 1 and transmitted through the subject 24, and the radiation generation apparatus 11 and the radiation detection apparatus 21. Is provided with a control device 22 that performs coordinated control.

  The control device 22 performs integrated control of the radiation generator 11 and the radiation detector 26. The drive circuit 13 outputs various control signals to the radiation tube 1 under the control of the control device 22. In this embodiment, the drive circuit 13 is housed inside the storage container 12 together with the radiation tube 1, but may be disposed outside the storage container 12. The emission state of the radiation 10 emitted from the radiation generator 11 is controlled by the control signal output from the drive circuit 13. The radiation 10 emitted from the radiation generating device 11 is adjusted in its irradiation range by the movable diaphragm 16, is emitted to the outside of the radiation generating device 11, passes through the subject 24, and is detected by the detector 26. The detector 26 converts the detected radiation into an image signal and outputs the image signal to the signal processing unit 25. The signal processing unit 25 performs predetermined signal processing on the image signal under the control of the control device 22, and outputs the processed image signal to the control device 22. The control device 22 outputs a display signal for displaying an image on the display device 23 to the display device 23 based on the processed image signal. The display device 23 displays an image based on the display signal on the screen as a captured image of the subject 24.

  A representative example of radiation is X-ray, and the radiation generating tube 1, the radiation generating device 11, and the radiation imaging system of the present invention can be used as an X-ray generating tube, an X-ray generating device, and an X-ray imaging system. The X-ray imaging system can be used for nondestructive inspection of industrial products and pathological diagnosis of human bodies and animals.

Example 1
A radiation generating tube 1 having the configuration shown in FIG. 1 was produced. The radiation emitted in this example is X-rays. First, in order to produce the target 5, a disk-shaped high-pressure synthetic diamond having a diameter of 5 mm and a thickness of 1 mm was prepared as a support substrate 7a. A tungsten film having a diameter of 3 mm and a thickness of 6 μm was formed as a target layer 7b on one surface of the diamond substrate by a sputtering method using a metal mask. In this embodiment, the tungsten film pattern is formed using a metal mask. However, photolithography may be used, or a printing method or the like may be used. Subsequently, the shielding member 6 processed with tungsten and the target 9 were integrated by brazing using BAg8 (silver brazing) as a brazing material.

  Next, the electron emission source 5 having an impregnated type hot cathode and the Kovar cathode 3 were integrated by welding. Subsequently, in the form shown in FIG. 4A, a disc-shaped NEG60 (made by SAES GETTERS SPA, product name: ST707) having a diameter of 6 mm and a height of 3 mm is applied to the cathode 3 using the adhesive 41. And a maximum height roughness Rz: 10 μm). The surface bonded to the NEG 8 of the cathode 3 was subjected to cutting using a lathe and a milling machine so that the maximum height roughness Rz of the surface was 20 μm. As the adhesive 41, a highly heat-conductive, high-heat-resistant, high-vacuum-compatible adhesive containing silver particles (AREMCO PRODUCTS INC, manufactured by USA, trade name: Pyroduct 597-A, thermal conductivity: 9 .1 W / (m / K)) was used. Note that a copper pipe (not shown) is attached to the cathode 3, and the outer surface and the inner surface are communicated with each other.

  Next, as shown in FIG. 1, the target 7 is irradiated with the electron beam 9 with the anode 4 made of Kovar facing the electron emission source 5 having an impregnated type hot cathode through the insulating tube 2. And fixed by welding. A ring-shaped metallic member (not shown) is provided at both ends of the insulating tube 2 by brazing so that it can be connected and fixed to the anode 4 and the cathode 3 by welding.

Then, the process for making the tube | pipe which integrated said anode 4, the cathode 3, and the insulating tube 2 into the radiation tube 1 was performed. First, it is connected to an evacuation system via a copper pipe (not shown) provided on the cathode 3, the inside of the tube is evacuated to 5 × 10 ⁻⁴ Pa, and heated to 450 ° C. by a heater from the outside of the tube. Then, the inside of the tube was vacuum baked. This vacuum baking has two roles of degassing members in the radiation tube 1 and activating the NEG 8. By vacuum baking, the gas adsorbed on the members in the radiation tube 1 is degassed, and the degassing when using the radiation tube 1 can be reduced, and the degree of vacuum in the tube can be maintained at a high vacuum. It becomes easy. Further, during vacuum baking, the NEG 8 attached to the cathode 3 is also heated, and the NEG 8 is activated, so that the gas adsorption ability of the NEG 8 can be fully exhibited. Following the vacuum baking process, the activation process of the electron emission source 5 was performed, and finally the copper pipe was cut and sealed to form the radiation tube 1.

  Subsequently, the drive circuit 13 is electrically connected to the cathode 3 and the anode 4 of the radiation tube 1, and the radiation tube 1 and the drive circuit 13 are housed inside the storage container 12, and FIG. A radiation generator 11 having the structure shown was produced.

Next, in order to evaluate the discharge resistance performance of the radiation generator 11 and the stability of the anode current, an evaluation system shown in FIG. 5 was prepared. In the evaluation system of FIG. 5, a dosimeter 56 is disposed at a position 1 m ahead of the radiation emission window 14 of the radiation generator 11. The dosimeter 56 can measure the radiation output intensity of the radiation generator 11 by being connected to the drive circuit 13 via the measurement control device 53. The driving conditions for the radiation generator 11 of this embodiment are as follows: the tube voltage Va of the radiation tube 1 is +110 kV, the current density of the electron beam 9 applied to the target layer 7b is 20 mA / mm ² , and the electron irradiation period is 3 seconds. The non-irradiation period was set to pulse driving in which 57 seconds were alternately repeated. The detected anode current was measured by the current measuring device 54 using the tube current flowing from the target layer 7b to the ground electrode 52 as the anode current, and an average value for 1 second in the center of the electron irradiation pulse width period was adopted. The rise time and fall time of the electron irradiation pulse were both 0.1 seconds. The stability evaluation of the anodic current was performed by evaluating the anodic current after 10 hours from the start of radiation output with the retention rate normalized by the initial anodic current. In addition, the radiation tube 1 of the present example was grounded with an anode, and a weight of 0.1 N was applied to the shielding member 6 of the radiation tube 1 at 0.1 Hz during the operation period. In the evaluation of the stability of the anode current, the gate current flowing between the electron emission source 5 and the gate electrode (not shown) was stabilized by a negative feedback circuit (not shown) so that the fluctuation was within 1%. The retention rate of the anode current of the radiation generator 1 of the present example was 0.99. It was confirmed that the radiation generating apparatus 1 of the present example did not show a significant variation in X-ray output even after a long driving history, and a stable radiation output intensity was obtained.

(Example 2)
A radiation tube and a radiation generating device were produced in the same manner as in Example 1 except that the NEG 8 was mounted in the form shown in FIG. 4 (e) and fixed to the inner surface of the anode 4. As the fixing member 42, a spring material made of SUS304 was used, and the attachment surface of the inner surface of the anode 4 was cut using a lathe and a milling machine so that the maximum height roughness Rz was 50 μm. As in Example 1, the radiation generating apparatus of the present example also confirmed that a stable X-ray output intensity was obtained without noticeable fluctuations in radiation output even after a long driving history. It was done.

(Example 3)
When the radiation imaging system having the configuration shown in FIG. 3 is manufactured using the radiation generator manufactured in Example 1, the radiation generator is provided with a stable X-ray output intensity even when used for a long time. X-ray images could be acquired stably.

  1: radiation tube, 2: insulation tube, 3: cathode, 4: anode, 8: NEG, 10: radiation, 11: radiation generator, 12: storage container, 14: radiation emission window, 15: insulating fluid, 41 : Adhesive, 42: Fixing member, 24: Subject, 21: Radiation detection device, 22: Control device

Claims (14)

An envelope comprising a tubular insulating tube, a cathode attached to one end of the insulating tube, and an anode attached to the other end of the insulating tube, and a non-evaporable getter inside the envelope An attached radiation tube,
The non-evaporable getter is fixed to a mounting surface having a maximum height roughness Rz of 0.1 μm or more and 500 μm or less.   The radiation tube according to claim 1, wherein a maximum height roughness Rz of the attachment surface is 0.8 μm or more and 100 μm or less.   The radiation tube according to claim 1, wherein the attachment surface is an inner surface of the envelope, and the non-evaporable getter is fixed to the inner surface of the envelope via an adhesive.   The radiation tube according to claim 3, wherein the adhesive is also disposed on an outer periphery of an end portion of the non-evaporable getter on the inner surface side of the envelope.   The attachment surface is an inner surface of the envelope, and an adhesive is disposed on an outer periphery of an end portion of the non-evaporable getter on the inner surface side of the envelope so that the non-evaporable getter serves as an inner surface of the envelope. The radiation tube according to claim 1, wherein the radiation tube is fixed to the tube.   The non-evaporable getter is fixed to an inner surface of the envelope via a fixing member, and a surface of the fixing member facing the non-evaporable getter is the mounting surface. Item 4. The radiation tube according to any one of Items 1 to 3.   The radiation tube according to claim 6, wherein the non-evaporable getter is attached to the fixing member via an adhesive.   The radiation tube according to claim 3, wherein the adhesive contains a heat conductive material.   The radiation tube according to claim 8, wherein the thermally conductive material is at least one selected from the group consisting of silver, copper, gold, diamond, aluminum, silicon carbide, aluminum nitride, and graphite.   The radiation tube according to claim 3, wherein the adhesive has a thermal conductivity of 0.5 W / (m · K) or more.   The radiation tube according to claim 6, wherein the fixing member is an elastic member, and the non-evaporable getter is fitted to the fixing member.   The non-evaporable getter is fixed to the inner surface of the envelope by being fixed to the envelope by a fixing member, and the inner surface of the envelope is the mounting surface. The radiation tube according to claim 1 or 2. The radiation generating tube according to any one of claims 1 to 12,
A storage container that contains the radiation generating tube and has a radiation emission window for taking out radiation generated from the radiation generating tube;
A radiation generating apparatus, wherein an excess space inside the storage container is filled with an insulating fluid. A radiation generator according to claim 13;
A radiation imaging system comprising: a radiation detection device that detects radiation emitted from the radiation generation tube and transmitted through a subject; and a control device that controls the radiation generation device and the radiation detection device in a coordinated manner.

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