JP2017050070A - X-ray generation tube, x-ray generation apparatus, x-ray imaging system and adjustment method for x-ray generation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray generation tube having high reliability, which has an insulation tube having an identification pattern portion formed therein and suppressed in positional fluctuation or deformation of a focal point, and an X-ray generation apparatus having the same.SOLUTION: An X-ray generation tube 1 having a transmission type target as an end window, includes: an insulating tube 2; a cathode 4 which is connected to one end of the insulating tube 2 in a tube axis direction (x direction) and has an electron emitting portion 4c; and an anode 5 having a target 5b, which is connected to the other end of the insulating tube 2 in the tube axis direction and generates X-rays upon irradiation of electrons. X-rays are generated while the output intensity thereof is controlled by the irradiation amount of an electron beam to the target 5b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an X-ray generation tube, an X-ray generation apparatus, an X-ray imaging system, and an adjustment method thereof that can be applied to, for example, medical devices and non-destructive inspection apparatuses.

  The X-ray generator includes an X-ray generator tube, a tube voltage circuit that applies a tube voltage, and a cathode control circuit that controls the electron emission unit, so that the exposure conditions can be controlled from the outside.

  It is known to add an identification pattern portion to an X-ray generating tube. In Patent Document 1, a barcode obtained by encoding a model number and a serial number is affixed to an X-ray generation tube, and the usage time for each X-ray generation tube is recorded based on the identification pattern portion to generate an X-ray. Presenting the time to replace the tube is disclosed.

Japanese Patent Laid-Open No. 5-283192

  The X-ray generation tube is a replacement part that is replaced based on a predetermined operation history, and the X-ray generation tube to be replaced is designated with a specific model number so as to be adapted to each X-ray generation device. . Therefore, it is required for manufacturing and maintenance to provide an identification pattern portion for each X-ray generation tube and manage the X-ray generation tube individually. In some cases, the identification pattern portion is provided to the insulating tube of the X-ray generation tube from the viewpoint of securing the installation area of the identification pattern portion.

  On the other hand, when performing X-ray imaging using an X-ray generation tube having an identification pattern portion formed on an insulating tube, the quality of the captured image may be degraded in uniformity and reproducibility.

  According to the study by the inventors of the present application, the deterioration of the imaging quality is caused by the change in the position or shape of the focus formed on the target and the generation of X-rays, and the identification pattern portion is related to the change in the focus position or shape. I found out.

  An object of the present invention is to provide a reliable X-ray generator tube and an X-ray generator that have an insulating tube in which an identification pattern portion is formed, and in which focal position variation or deformation is suppressed, and An object of the present invention is to provide an X-ray imaging system capable of acquiring a high-quality X-ray image.

The first of the present invention is an insulating tube, a cathode connected to one end of the insulating tube in the tube axis direction and having an electron emitting portion, and a target connected to the other end of the insulating tube and emitting X-rays by electron irradiation. An X-ray generating tube comprising: an anode comprising:
An identification pattern portion is provided on an outer periphery of the insulating tube, and the identification pattern portion has a higher sheet resistance than the insulating tube.

  According to a second aspect of the present invention, there is provided a method for adjusting an X-ray generator having an X-ray generator tube having an insulating tube, and a tube voltage circuit for applying a tube voltage to the X-ray generator tube. The line generation tube has an identification pattern portion in which information on the X-ray generation tube is encoded on the insulating tube, the identification pattern portion has a higher sheet resistance than the insulation tube, and is based on the identification pattern portion. The tube voltage output from the tube voltage circuit is adjusted.

  According to the present invention, there is provided a highly reliable X-ray generation tube and an X-ray generation device in which fluctuations in the focal position are suppressed even in an X-ray generation tube in which an identification pattern portion is formed on an insulating tube. It becomes possible to provide. In addition, by providing the X-ray generator tube of the present invention, it is possible to provide an X-ray imaging system that can stably acquire a high-quality X-ray image.

Sectional view (a), three-plane views (b), (d), (e), partial enlarged view (c), and sectional view showing potential distribution, showing an X-ray generating tube according to the first embodiment of the present invention (F) is a potential gradient graph (g). It is sectional drawing (a) and front view (b) which show the X-ray generator tube concerning 2nd Embodiment of this invention. It is the front view (a)-(d) and side view (e) which show the X-ray generation tube in connection with 3rd Embodiment of this invention. It is a block diagram which shows the X-ray generator which concerns on 4th Embodiment of this invention. It is a block diagram which shows the X-ray imaging system which concerns on 5th Embodiment of this invention. It is a flowchart which shows the manufacturing process of X-ray generator tube and X-ray generator concerning the 6th-8th embodiment of this invention, and the process of systematization. Two views (a), (b), a partially enlarged view (c), a sectional view (d), a graph (e) showing a potential gradient, and a sectional view showing a potential distribution of the X-ray generating tube according to the first reference embodiment It is a figure (f). Two views (a) and (b), a partially enlarged view (c), a sectional view (d), a graph (e) showing a potential gradient, and a sectional view showing a potential distribution of the X-ray generating tube according to the second reference embodiment It is a figure (f). Two views (a) and (b), a partially enlarged view (c), a cross-sectional view (d), a graph (e) showing a potential gradient, and a cross-section showing a potential distribution, of an X-ray generating tube according to a third reference embodiment It is a figure (f).

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The dimensions, materials, shapes, and relative arrangements of the constituent members described in these embodiments are not intended to limit the scope of the present invention. In addition, a well-known or publicly known technique in the technical field is applied to a part that is not particularly illustrated or described in the present specification. <X-ray generator tube>
First, the basic configuration of the X-ray generator tube will be described with reference to FIG.

  FIG. 1 shows an X-ray generation tube 1 having a transmission type target as an end window. The X-ray generating tube is connected to the insulating tube 2, the cathode 4 provided with one end in the tube axis direction (x direction) of the insulating tube 2 and including the electron emission portion 4 c, and the other end of the insulating tube 2 in the tube axis direction. And an anode 5 including a target 5b that generates X-rays by electron irradiation. With such a configuration, it is possible to generate X-rays whose output intensity is controlled by the amount of electron beam irradiation to the target 5b.

  The cathode 4 includes an electron emission source 4b including an electron emission portion 4c, and a cathode member 4a connected to the electron emission source 4b and the insulating tube 2. The cathode 4 is an electron emission source, an electrode that defines the cathode potential of the X-ray generator tube 1, and a part of the envelope of the X-ray generator tube 1.

  The anode 5 includes a target 5b including a target layer 5c and a support substrate 5d, and an anode member 5a connected to the target 5b and the insulating tube 2. It also serves as a structural member that defines the vacuum envelope. The anode 5 includes an X-ray generation region, an electrode that defines the anode potential of the X-ray generation tube 1, and a part of the envelope of the X-ray generation tube 1.

  An identification pattern portion 7 is provided on the insulating tube 2 of the X-ray generating tube 1 of the present embodiment. The identification pattern unit 7 is obtained by encoding information related to the X-ray generator tube 1. The encoded information includes date, time, model number, lot number, serial number, manufacturing apparatus, and manufacturing factory. Manufacture of an X-ray generator tube including at least one of an inspection apparatus and an inspector. The identification pattern portion that is a feature of the present invention will be described later.

As a result of diligent studies by the inventors of the present application, the following four observation facts were confirmed by finding a problem related to a reduction in focus quality in an X-ray generator tube having an identification pattern portion formed on an insulating tube.
-The presence / absence of the focus change may correspond to the presence / absence of the identification pattern on the surface of the insulating tube.
The focal amount variation (positional deviation amount) depends on the sheet resistance of the identification pattern part, and the variation amount is large when the resistance is low. If the resistance value exceeds a certain resistance value, the influence is suppressed.
・ Focus variation direction (azimuth misalignment) depends on the position of the identification pattern in the tube circumferential direction.
・ Focus variation direction (displacement in the tube diameter direction) depends on the position of the identification pattern in the tube axis direction.

  Based on such observation facts, the inventors of the present application have estimated that “the fluctuation factor of the focal position is that the identification pattern part disturbs the electrostatic field between the anode and the cathode”. Problems to be solved by the present invention will be described with reference to FIGS. 7 to 9 showing X-ray generating tubes according to first to third reference embodiments.

<First Reference Form>
FIG. 7 shows two views (a) and (b) of the X-ray generator tube 300 according to the first embodiment, an enlarged view (c) of FIG. 1 (b), a sectional view (d), and a potential gradient. It is sectional drawing (f) which shows a graph (e) and electric potential distribution.

  As shown in FIGS. 7A to 7F, the identification pattern portion is not provided on the insulating tube 302 of the X-ray generation tube 300 according to the first reference embodiment.

The X-ray generation tube 300 includes a cathode 4 including a cathode member 4a and an electron emission source 4b, an anode 5 including an anode member 5a and a target 5b, and an insulating tube 302.
The electrostatic field in the internal space of the X-ray generation tube 300 is defined by the cathode 4, the anode 5, and the insulating tube 302. In this reference embodiment, since the insulating tube 302 has uniform insulation characteristics in the tube circumferential direction, the potential distribution in the X-ray generation tube 300 is x1 axis (y = 0) has rotational symmetry around. For this reason, the electrons emitted from the electron emitting portion 4c travel straight toward the target 5b and are accelerated to form a focal point 308 on the target 5b as shown in FIGS. 7 (c) and 7 (f). The focal point 308 exhibits a perfect circular beam profile having circumferential symmetry around the focal center 308c.

  As shown in FIG. 7 (d), the symmetry of the potential distribution of the X-ray generator tube 300 of the present embodiment has three virtual axes parallel to the X axis: x0 axis, x1 axis, and x2 axis. It will be explained as a representative. The three axes x0 axis, x1 axis, and x2 axis have (y coordinate, z coordinate) of (−Ψ / 2, 0), (0, 0), (+ Ψ / 2, 0), respectively. It is a virtual axis taken parallel to the x direction. Here, Ψ is the outer diameter (diameter) of the insulating tube 302, and the x direction is parallel to the tube axis direction.

  As shown in FIG. 7F, since the electron emission source 4b protrudes from the cathode member 4a toward the anode member 5 to define the cathode potential, the equipotential surface close to the cathode member 4a side emits electrons. Depending on the protruding shape of the source 4, it is deformed symmetrically about the x1 axis. That is, the electric field close to the cathode member 4a side has an axisymmetric potential distribution across the x1 axis in the tube diameter direction (in the yz plane).

  Further, as shown in FIG. 7 (f), the equipotential surface close to the anode 5 side extends in parallel to the anode 5 following the anode 5 because the influence of the protruding shape of the electron emission source 4 is small. Is read.

  The symmetry of the potential distribution in the tube circumferential direction can also be read from FIG. 7E showing the potential gradient in the tube axis direction. The potentials on the x0 axis and the x2 axis are (0 <= X <= ta) It is in agreement well. In addition, the dashed-dotted line shown in the potential gradient graph of FIG.7 (e) has shown the virtual linear potential gradient in which the equipotential surface was formed at equal intervals from the cathode member 4a to the anode member 5a.

  As described above, when the identification pattern portion is not provided, the center 308c of the focal point 308 is formed on the target 5b without being influenced by the identification pattern portion 7 based on the symmetry of the insulating tube 302 in the tube circumferential direction. It can be seen that

<Second Reference Form>
FIG. 8 shows two views (a) and (b) of the X-ray generator tube 320 according to the second embodiment, an enlarged view (c) of FIG. 1 (b), a cross-sectional view (d), and a potential gradient. It is sectional drawing (f) which shows a graph (e) and electric potential distribution.

  FIG. 8A shows an X-ray generating tube 320 according to a reference form in which an identification pattern portion 327 having a sheet resistance lower than that of the insulating tube 302 is provided on the insulating tube 302.

  In the identification pattern portion 327 of this reference embodiment, a model number and a serial number are recorded on the base portion 327b as a printing portion 327a. In the reflectance with respect to visible light of 550 nm, the base portion 327b is 10% and the printing portion 327a is 75%.

  The sheet resistance of the identification pattern portion 327 of this reference form is 1/10 of the sheet resistance of the insulating tube 302. In addition, in each embodiment and reference form described in the present specification, the sheet resistance means a sheet resistance defined by an electric field along the tube axis direction in accordance with an X-ray generating tube to which a tube voltage is applied. The sheet resistance in the tube axis direction. Further, the printing portion 327a and the base portion 327b are not distinguished in sheet resistance.

  Further, the identification pattern portion 327 of the present embodiment is provided to the insulating tube 302 in a part of the pipe circumferential direction as shown in FIGS. 8 (a), (b), (d), and (f). ing.

  The X-ray generation tube 320 is different from the X-ray generation tube 300 of the first reference form in that the X-ray generation tube 320 includes an identification pattern portion 327 having a sheet resistance of 1/10 that of the insulating tube 302.

  The identification pattern portion 327 of the present embodiment is located in a region between the anode side end portion (x = te) of the electron emission source 4b and the connection portion (x = 0) of the cathode member 4a. In other words, the identification pattern portion 327 is positioned on the cathode 4 side so as to overlap the electron emission source 4b in the tube axis direction.

  The electrostatic field in the internal space of the X-ray generation tube 320 is defined by the cathode 4, the anode 5, the insulating tube 302, and the identification pattern portion 327. Since the insulating tube 302 provided with the identification pattern portion 327 has non-uniform insulating characteristics in the tube circumferential direction, the potential distribution in the X-ray generating tube 320 is as shown in FIG. It has asymmetry across the X1 axis (y = 0). Due to the asymmetry of the potential distribution, the electrons emitted from the electron emission portion 4c are shifted in the direction away from the identification pattern portion 327 on the target 5b as shown in FIGS. 8B, 8C, and 8F. A focal point 329 is formed. Further, as shown in FIGS. 8B and 8C, the focal point 329 exhibits a flat beam profile extending in a direction away from the identification pattern portion 327 because the symmetry around the focal point center 329 c is lost.

  Since the electrons emitted from the electron emission portion 4c are gradually accelerated from the vicinity of the anode side end (x = te) of the electron emission source 4b, the electrons in the vicinity of the electron emission portion 4c are immediately before colliding with the target 5b. Are also slow and are susceptible to the asymmetry of the electric field in the radial direction of the tube. Therefore, in the present embodiment, as shown in FIG. 8F, the potential on the x0 axis in the vicinity of the anode side end (x = te) of the electron emission source 4b is lower than the potential on the x2 axis. Asymmetry of the electrostatic field that repels electrons from the x0 axis side where the portion 327 is provided is formed.

  The asymmetry of the potential distribution in the tube circumferential direction is also read from FIG. 8 (e) showing the potential gradient in the tube axis direction, and the potentials on the x0 axis and the x2 axis have different portions. ing.

  In particular, it can be seen that the region where the potential gradient on the x0 axis is flat corresponds to the region in the tube axis direction where the identification pattern portion 327 is provided, and is a dominant factor of the asymmetric potential gradient. A region where the potential gradient on the x0 axis is flat corresponds to a region where the potential gradient defined by the insulating tube 302 is reduced because the sheet resistance of the identification pattern portion 327 is low.

  Since the tube voltage Va is applied without depending on the presence / absence of the identification pattern portion 327, a potential higher than that on the x2 axis is present in each of the cathode side and anode side regions from the region corresponding to the identification pattern portion 327. It can be read from FIG. 8 (e) that a gradient is formed.

<Third Reference Form>
FIG. 9 shows two views (a) and (b) of the X-ray generation tube 340 according to the third embodiment, an enlarged view (c) of FIG. 1 (b), a sectional view (d), and a potential gradient. It is sectional drawing (f) which shows a graph (e) and electric potential distribution.

  FIG. 9A shows an X-ray generation tube 340 in which an identification pattern portion 347 having a sheet resistance lower than that of the insulating tube 302 is provided on the insulating tube 302.

  In the identification pattern portion 347 of this reference form, as in the second reference form, the model number and serial number are recorded as a text pattern 347a on the print layer 347b. The sheet resistance of the identification pattern portion 347 of this reference form is 1/10 of the sheet resistance of the insulating tube 302.

  The X-ray generation tube 340 is different from the X-ray generation tube 300 of the first reference embodiment in that the X-ray generation tube 340 includes an identification pattern portion 347 having a sheet resistance that is 1/10 that of the insulating tube 302.

  In addition, the identification pattern portion 347 of the present embodiment is located between the anode side end (x = te) and the anode 5 (x = ta) of the electron emission source 4b. That is, the X-ray generation tube 340 is different from the X-ray generation tube 320 of the second reference form in that the identification pattern portion 347 is provided in a region that does not overlap the electron emission source 4b in the tube axis direction. .

  The electrostatic field in the internal space of the X-ray generation tube 340 is defined by the cathode 4, the anode 5, the insulating tube 302, and the identification pattern portion 347. Since the insulating tube 302 provided with the identification pattern portion 347 has non-uniform insulating characteristics in the tube circumferential direction, the potential distribution in the X-ray generation tube 340 is as shown in FIG. It has asymmetry across the x1 axis (y = 0). Due to this asymmetric potential distribution, the electrons emitted from the electron emission portion 4c form a focal point 349 shifted in the direction approaching the identification pattern portion 347 on the target 5b as shown in FIGS. 9B and 9C. . Further, as shown in FIGS. 9B, 9C, and 9F, the focal point 349 has a flat beam profile extending in the direction of approaching the identification pattern portion 347 because the symmetry around the focal point center 349c is broken. Yes.

  In the present embodiment, as shown in FIG. 9 (f), the potential on the x0 axis near the anode side end (x = te) of the electron emission source 4b is higher than the potential on the x2 axis, and the identification pattern portion 347 An asymmetry of the electrostatic field that attracts electrons is formed on the x0 axis side where is provided.

  The asymmetry of the potential distribution in the tube circumferential direction is also read from FIG. 9 (e) showing the potential gradient in the tube axis direction, and the potentials on the x0 axis and the x2 axis have different portions. ing.

  In particular, the region where the potential gradient on the x0 axis is flat corresponds to the region in the tube axis direction where the identification pattern portion 347 is provided, and it can be seen that this is the dominant factor of this asymmetric potential gradient. A region where the potential gradient on the x0 axis is flat corresponds to a region where the potential gradient defined by the insulating tube 302 is reduced because the sheet resistance of the identification pattern portion 347 is low.

  Since the tube voltage Va is applied without depending on the presence or absence of the identification pattern portion 347, a potential gradient higher than that on the x2 axis is present in each of the cathode side and anode side regions from the region corresponding to the identification pattern portion 347. It can be read from FIG.

  As described above, as described in the second and third reference embodiments, when the sheet resistance of the identification pattern portion formed on the insulating tube is lower than that of the insulating tube, the positional deviation of the focal point and the deformation of the focal point shape occur. was there.

<First Embodiment>
FIG. 1 is a cross-sectional view (a), a trihedral view (b), (d), (e), and a partially enlarged view of FIG. 1 (b) showing an X-ray generating tube 1 according to the first embodiment of the present invention. 1 (c), a cross-sectional view (f) showing a potential distribution, and a potential gradient graph (g). 1B, 1C, 1D, and 1E are respectively a front view, a rear view, a cathode side side view, and an anode side side view of the X-ray generator tube 1 according to the first embodiment. is there.

  In FIGS. 1A and 1E, an X-ray generating tube 1 in which an identification pattern portion 7 having a sheet resistance higher than that of the insulating tube 2 is provided on the insulating tube 2 is shown as the first embodiment. .

  In the identification pattern unit 7 of the present embodiment, the model number and the serial number are recorded as the text pattern 7a on the print layer 7b, as in the second and third reference embodiments. The sheet resistance of the identification pattern portion 7 of this embodiment is 10 times the sheet resistance of the insulating tube 2. In addition, the identification pattern portion 7 of the present embodiment includes an insulating tube in a part of the pipe circumferential direction as shown in FIGS. 1 (a), (b), (d), (e), and (f). 2 is assigned. 1E is a front view seen from the side of the support line AA in FIG. 1B, and FIG. 1F is the side of the support line BB in FIG. 1B. It is the rear view seen from.

  The X-ray generator tube 1 of the present embodiment is different from the X-ray generator tubes 320 and 340 of the second and third reference embodiments in that the X-ray generator tube 1 includes the identification pattern portion 7 having a sheet resistance 10 times that of the insulating tube 2. Is different.

  The identification pattern portion 7 of the present embodiment is located in a region between the anode side end portion (x = te) of the electron emission source 4b and the connection portion (x = 0) of the cathode member 4a. In other words, the identification pattern portion 7 is positioned on the cathode 4 side so as to overlap the electron emission source 4b in the tube axis direction.

  Since the identification pattern portion 7 of the present embodiment has a higher insulating property than the insulating tube 2, the influence on the electrostatic field defined by the insulating tube 2 is dominated by the insulating tube 2. The electrostatic field defined by the insulating tube 2 is hardly affected. Therefore, the electrostatic field in the internal space of the X-ray generation tube 1 is defined by the cathode 4, the anode 5, and the insulating tube 2 as in the first reference embodiment having no identification pattern portion.

  Although the identification pattern portion 7 is provided, the insulating tube 2 has a uniform insulating characteristic in the tube circumferential direction surrounding the x1 axis, and therefore, as shown in FIGS. The potential distribution in the line generating tube 1 has rotational symmetry about the x1 axis (y = 0). For this reason, the electrons emitted from the electron emission portion 4c travel straight toward the target 5b and are accelerated to form a focal point 8 on the target 5b as shown in FIG. 1 (f). As shown in FIG. 1C, the focal point 8 exhibits a perfect circular beam profile having symmetry in the circumferential direction around the focal point center 8c.

  As shown in FIG. 1 (f), the symmetry of the potential distribution of the insulating tube 2 of the X-ray generator tube 1 of this embodiment has three virtual axes parallel to the X axis, the x0 axis and the x1 axis. The x2 axis will be described as a representative. The three axes x0 axis, x1 axis, and x2 axis have y and z coordinates (−Ψ / 2, 0), (0, 0), (+ Ψ / 2, 0), respectively, It is a virtual axis that is parallel. However, (psi) is the outer periphery diameter (diameter) of the insulating tube 2, and the x direction is taken in parallel with the tube-axis direction.

  As shown in FIG. 1 (f), since the electron emission source 4b protrudes from the cathode member 4a toward the anode member 5 to define the cathode potential, the equipotential surface close to the cathode member 4a side is the electron emission. Depending on the protruding shape of the source 4, it is deformed symmetrically about the x1 axis. That is, the electric field close to the cathode member 4a side has an axisymmetric potential distribution across the x1 axis in the tube diameter direction (in the yz plane).

  Further, as shown in FIG. 1 (f), the equipotential surface close to the anode 5 side extends in parallel to the anode 5 following the anode 5 because the influence of the protruding shape of the electron emission source 4 is small. Is read.

  The symmetry of the potential distribution in the tube circumferential direction can also be read from FIG. 7E showing the potential gradient in the tube axis direction. The potentials on the x0 axis and the x2 axis are (0 <= X <= ta) It is in agreement well. 1 (g) is a virtual linear potential gradient in which equipotential surfaces are formed at equal intervals from the cathode member 4a to the anode member 5a, as in FIG. 7 (e). Is shown.

  As described above, when the identification pattern portion 7 having a sheet resistance higher than that of the insulating tube 2 is provided in the insulating tube 2, the focal point 8 and the focal center 8 c are based on the symmetry in the tube circumferential direction of the insulating tube 2. It can be seen that it is formed on the target 5 b without being affected by the identification pattern portion 7.

  The identification pattern portion 7 only needs to have a high resistance so that the insulating tube 2 does not affect the electrostatic field distribution of the X-ray generating tube 1, and is preferably higher than the sheet resistance of the insulating tube 2. More preferably, it is 10 times or more of the resistance.

The sheet resistance of the insulating tube 2 is a range of 1 × 10 ¹¹ to 1 × 10 ¹⁶ Ω / □ at room temperature. Therefore, the sheet resistance of the identification pattern portion 7 is preferably 1 × 10 ¹⁶ Ω / □ or more.

  The insulating tube 2 is an insulator such as glass or ceramic and has a tubular structure having airtightness and heat resistance. The insulation of the insulating tube 2 is required to have an insulating property so that a tube voltage can be continuously applied between the anode 5 and the cathode 4. On the other hand, it is possible to impart conductivity that allows tube current within the limits of power consumption and heat generation. The insulating tube provided with conductivity can attenuate the influence of charging inside and outside the insulating tube in a time several times the time constant τ.

  Insulating tube to which conductivity is imparted is a mode of bulk current field potential regulation in which particles having conductivity and semiconductivity are dispersed on the tube wall itself, or a high resistance film, a semiconductor film on the inner surface or outer surface of the tube wall The current field potential defining layer is formed.

  Note that the time constant τ (seconds) is an observable amount given by ε × ρ when the volume resistance ρ dielectric constant ε is considered, considering the relaxation time of the charged charge flowing in the tube axis direction, and the sheet resistance Rs. , The sheet capacity Cs is an observable amount given by Rs × Cs.

  A metal oxide such as glass or ceramic can be applied to the insulating tube 2. When the insulating tube 2 is a ceramic tube, a surface reinforcing layer that forms a compressive stress on the ceramic tube body by applying a glaze to the outer surface of the ceramic tube and firing it for the purpose of ensuring the atmospheric pressure strength of the vacuum tight container (FIG. 6, surface enhancement layer). In the first embodiment, a surface enhancement layer (not shown) is used as the current field potential regulating layer.

<Second Embodiment>
Next, the modification of 1st Embodiment is demonstrated using FIG. 2 which shows the X-ray generation tube 21 which concerns on 2nd Embodiment.

  The X-ray generation tube 21 of the second embodiment differs from the X-ray generation tube 1 of the first embodiment only in the position of the identification pattern portion 7.

  Therefore, the identification pattern portion 7 is common to the first embodiment in that it has a sheet resistance 10 times that of the insulating tube 2. Since the identification pattern portion 7 does not disturb the electrostatic field defined by the insulating tube 2, even if it is located on the anode side of the end surface on the anode 5 side of the electron emission source 4b, the position of the focal point does not change. That is, the identification pattern portion 7 having a sheet resistance higher than that of the insulating tube 2 is included in the aspect of the present invention regardless of the position of the insulating tube 2 in the tube axis direction.

<Third Embodiment>
Next, a modification of the first embodiment will be described with reference to FIGS. 3A to 3F showing X-ray generation tubes 31a to 31e according to the third embodiment.

  Each of the third embodiments shown in FIGS. 3A to 3E is different from the first embodiment in that it includes an identification pattern portion encoded in a different manner.

  The identification pattern portion 17 shown in FIG. 3A is obtained by printing a negative / positive inverted pattern of the identification pattern portion 7 of the first embodiment. The reflectance with respect to visible light of 550 nm is 75% for the base portion 17b and 10% for the print pattern portion 17a.

  Further, the identification pattern unit 27 shown in FIG. 3B is obtained by encoding a serial number into a two-dimensional pattern code. The reflectance for visible light at 550 nm is 75% for the base portion 27b and 5% for the print pattern portion 27a. 27c is a position reference for aligning the X-ray generation tube 31b in the tube circumferential direction. In each of the identification pattern portions 7, 17, and 27, the pattern is optically read based on the reflectance contrast between the print pattern portion and the base portion.

  Also, the identification pattern portions 37a and 37b shown in FIGS. 3C and 3D are one-dimensional barcodes obtained by encoding serial numbers. The identification pattern portions 37a and 37b are different in the barcode arrangement direction. In each of the identification pattern portions 37a and 37b, the pattern is optically read based on the reflectance contrast, similarly to the identification pattern portions 7, 17, and 27.

  Further, the identification pattern portion 47a shown in FIGS. 3E and 3F is a position reference for aligning the X-ray generation tube 31e in the tube circumferential direction, similarly to 27a. The identification pattern part 47 is an icon for improving the identification of 47a. As shown in FIG. 3F, the identification pattern portion 47a is formed at a unique position in the tube circumferential direction in the yz plane.

  Although the identification pattern portions 7, 17, 27, 37a, 37b, and 47 are provided by screen printing, the identification pattern applying method can be appropriately replaced with pattern applying means such as mask printing, ink jet printing, and gel jet printing. . The identification pattern applying method includes a method of attaching a label sheet on which a pattern is formed to an insulating tube, and a method of forming a pattern on a sheet attached to the insulating tube by printing or the like.

  As described above, the form of the identification pattern portion only needs to be identifiable by an optical sensor, an electrostatic field sensor or the like. In addition to text patterns, icons, monograms, two-dimensional pattern codes, one-dimensional barcodes, and the like are included. The optical identification method includes a form of reading a pattern portion having a reflection intensity distribution, and a form of reading a light emission intensity distribution of a self-luminous form such as fluorescence or phosphorescence. In addition to the optical identification method, intensity distributions of various physical quantities such as static electricity, magnetism, hardness, Young's modulus and the like are included in the read identification pattern portion of the present invention.

  Note that the identification pattern portion may be provided on the cathode and the anode. However, although possible, the space for forming the identification pattern portion on the cathode and the anode is limited, the mounting form in the X-ray generator, and the transporting form at the time of manufacture are masked by cables, collimators, gripping members, etc. And visibility may be limited. Therefore, the present invention is directed to an X-ray generating tube in which an identification pattern portion is formed on the outer periphery of an insulating tube from the viewpoint of discrimination.

<X-ray generator>
Next, a basic configuration of an X-ray generator to which the X-ray generator tube of the present invention is applied will be described. FIG. 4 shows an X-ray generator 101 provided with an X-ray generator tube 1 according to a fourth embodiment of the present invention. The X-ray generation apparatus 101 includes an X-ray generation tube 1, a drive circuit 106 for driving the X-ray generation tube 1, and a storage container 107 for storing the X-ray generation tube 1 and the drive circuit 106. Yes.

  The drive circuit 106a applies the tube voltage Va between the cathode 4 and the anode 5, and an accelerating electric field is formed between the target 5b and the electron emission source 4b. A line type necessary for imaging can be selected by appropriately setting the tube voltage Va corresponding to the layer thickness of the target layer 5c and the metal type.

  The storage container 107 for storing the X-ray generation tube 1 and the drive circuit 106 is preferably a container having sufficient strength as a container and excellent in heat dissipation, and its constituent material is a metal such as brass, iron or stainless steel. Material is used.

  An extra space other than the X-ray generation tube 1 and the drive circuit 106 in the storage container 107 is filled with an insulating fluid 108. The insulating fluid 108 is a liquid having electrical insulation, and has a role of maintaining electrical insulation inside the storage container 107 and a role as a cooling medium for the X-ray generation tube 1. As the insulating fluid 108, an electric insulating oil such as mineral oil, silicone oil or perfluoro oil, an insulating gas such as SF6, or the like is used.

  In the present embodiment, the drive circuit 106 is housed inside the storage container 107 together with the X-ray generator tube 1, but may be disposed outside the storage container.

  In the X-ray generation apparatus 101, when the X-ray generation tube 1 is replaced, the X-ray generation apparatus 101 can be adjusted or calibrated based on the identification pattern portion 7 given to the insulating tube 3, and therefore, the X-ray generation apparatus 101 It is possible to efficiently compensate for variations in the X-ray emission characteristics of the generator tube 1. In the present embodiment, since the identification pattern portion 7 having a sheet resistance higher than that of the insulating tube is provided, the X-ray generation apparatus 101 is controlled in a state where the variation in the focal position and the focal shape derived from the identification pattern portion 7 is suppressed. Adjustments can be made.

  As a result, various adjustments of the X-ray generator 101 can be speeded up and simplified. Therefore, not only can the X-ray emission characteristics of the X-ray generator 101 be stabilized, but also the operating rate of the X-ray generator 101 can be improved.

  In addition, this invention includes as an aspect the case where the tube voltage output from the tube voltage circuit 106a is adjusted based on the identification pattern part 7. FIG. Similarly, the present invention includes a case where the amount of electron emission emitted from the electron emission source 4b under the control of the cathode control circuit 106b is adjusted based on the identification pattern portion 7. The cathode control circuit 106b is connected to the electron emission unit 4b in order to control the amount of electron emission emitted from the electron emission unit 4c shown in FIG. 1 toward the target 5b.

  In addition, the X-ray generation apparatus 101 includes an identification sensor (not shown) that identifies the identification pattern unit 7, so that when the X-ray generation tube 1 is mounted, the X-ray generation tube 101 can reliably generate information about the X-ray generation tube. It is possible to output to the apparatus 101.

<X-ray imaging system>
Next, a basic configuration of an X-ray imaging system to which the X-ray generator tube of the present invention is applied will be described. FIG. 5 is a schematic configuration diagram showing an X-ray imaging system 200 according to the fifth embodiment.

  The system control apparatus 202 controls the X-ray generation apparatus 101 and the X-ray detection apparatus 201 in an integrated manner. The exposure operation of the X-ray generator 101 is controlled based on the drive signal of the drive circuit 106. The drive circuit 106 outputs various control signals to the X-ray generator tube 1 under the control of the system controller 202. The emission state of the X-ray bundle emitted from the X-ray generator 101 is controlled by a control signal output from the drive circuit 106.

  The X-ray flux emitted from the X-ray generator 101 passes through the subject 204 and is detected by the detector 206. The detector 206 converts the detected X-rays into image signals and outputs them to the signal processing unit 205. The signal processing unit 205 performs predetermined signal processing on the image signal under the control of the system control device 202, and outputs the processed image signal to the system control device 202.

  The system control device 202 outputs a display signal for displaying an image on the display device 203 to the display device 203 based on the processed captured image signal. The display device 203 displays an image based on the input display signal on the screen as a captured image of the subject 204.

  The X-ray imaging system can be used for nondestructive inspection of industrial products and pathological diagnosis of human bodies and animals.

  In the X-ray imaging system 200, when the X-ray generation tube 1 is installed or replaced, the imaging conditions of the X-ray imaging system system 200 can be adjusted based on the identification pattern portion 7 provided to the insulating tube. At this time, since the identification pattern portion having a sheet resistance higher than that of the insulating tube is included, the variation of the focal position and the focal shape derived from the identification pattern portion is suppressed, and the imaging condition of the X-ray imaging system 200 is Adjustments can be made.

  As a result, the effects of variations in the production lot of the X-ray generation tube 1 and variations between production lots that may affect the imaging results are effectively suppressed. That is, the X-ray generation apparatus 101 can be calibrated so that the “character” inherent to the X-ray generation tube 1 does not affect the imaging quality.

  According to this embodiment, each time the X-ray generator tube 1 is mounted, the trouble of performing various adjustments of the X-ray imaging system 200 can be saved, so that the adjustment of the X-ray imaging system 200 is speeded up and the work load is reduced. It becomes possible. Therefore, not only can the imaging quality of the X-ray imaging system 200 be stabilized, but also the operating rate of the X-ray imaging system 200 can be improved.

<Adjustment sequence>
Next, an adjustment sequence using the identification pattern unit 7 will be described with reference to FIGS. 6 (a) to 6 (c).

  FIG. 6A illustrates each step of the tube manufacturing process 700 of the X-ray generating tube related to the manufacturing process of the X-ray generating tube of the present invention.

The tube manufacturing process 700 includes the following steps.
-Step of preparing an insulating tube (step 702)
-Step of forming a surface enhancement layer on the surface of the insulating tube (step 704)
Step of forming a bonding member layer that stabilizes the bonding between the cathode member and the anode member (step 706)
Step of joining the cathode member and the electron emission source to form the cathode (Step 708)
A process of joining the insulating tube and the cathode (Step 710)
A process of joining the anode member and the electron emission source to form the anode (step 712)
-Step of joining the insulating tube and the anode (step 714)
A process of heating and evacuating the inside of the envelope formed by the insulating tube, cathode, and anode (step 716)
-Sealing the envelope (step 718)
-Checking the vacuum of the envelope (step 720)
A process for inspecting the withstand voltage characteristics between the anode and the cathode (step 722)
・ Process of inspecting envelope application (step 724)
A step of measuring the anode current and the like and inspecting the electron emission characteristics of the electron emission portion mounted on the X-ray generation tube (step 726)
A process for inspecting the X-ray emission characteristics of the X-ray generation tube (step 728)
Etc.

  The identification pattern portion can be applied to the insulating tube during or at any step from Step 702 to Step 728.

  In addition, it is possible to adjust the manufacturing conditions based on the identification pattern part after application between any manufacturing process and manufacturing process after the process in which the identification pattern part is applied.

  For example, in the process before step 704, an identification pattern portion associated with information related to the wettability of the insulating tube is provided, and in either of the layer formation steps of steps 704 and 706, the layer formation adjusted based on the identification pattern portion A layer can be formed under certain conditions. Similarly, an identification pattern portion associated with information related to the wettability of the insulating tube is provided, and joining can be performed under the joining conditions adjusted based on the identification pattern portion in either joining step 710 or 714. It becomes possible.

  In addition, in the processes from step 712 to step 728, an identification pattern portion associated with information related to target characteristics is given to the insulating tube, and the emission characteristics of the X-ray generation tube can be adjusted based on the identification pattern portion. Yes (step 730).

  The identification pattern portion may be encoded information related to the X-ray generator tube, or may be encoded identification code associated with information related to the X-ray generator tube. That is, the information related to the X-ray generator tube and the associated identification code are stored in the storage medium, and the information related to the X-ray generator tube associated with the identification code is read from the storage medium. Are included in the aspect of the method for adjusting the X-ray generation tube.

  FIG. 6B illustrates each step of the apparatus manufacturing process 750 for manufacturing the X-ray generation apparatus.

The device manufacturing process 750 includes the following processes.
・ Pipe manufacturing process 700
-The step of storing the X-ray generation tube in the storage container (step 730)
A step of mounting the tube voltage circuit on the X-ray generation tube and the storage container (step 732)
A process of mounting the cathode control circuit on the X-ray generator tube (step 734)
The device manufacturing process 750 is a process of filling the extra space of the X-ray generation tube of the storage container with insulating oil (step 736).
-Sealing the storage container to form a mono tank (step 738)
・ Process for inspecting the pressure resistance of the mono tank (step 740)
A process for inspecting the X-ray emission characteristics of the X-ray generator (Step 742)
And including.

  In the present invention, the identification pattern portion can be applied to the insulating tube during any step from Step 700 to Step 734 or in the step.

  In addition, it is possible to adjust the manufacturing conditions of the manufacturing process based on the identification pattern part after application between any manufacturing process and manufacturing process after the process in which the identification pattern part is applied.

  For example, in the process before step 730, an identification pattern portion associated with information related to the tube current-tube voltage characteristics of the X-ray generator tube is provided. In step 740 or 742, X-ray generation is performed based on the identification pattern portion. The driving conditions for driving the device can be adjusted. The parameter to be adjusted of the driving circuit includes the amount of electron emission emitted from the electron emission source. Further, the parameter to be adjusted of the drive circuit includes the upper limit of the tube voltage of the X-ray generation tube. By setting the upper limit of the tube voltage for each X-ray generator tube, it becomes possible to reduce the risk of discharge breakdown of the X-ray generator.

  The upper limit of the tube voltage identified for each X-ray generation tube is determined by the tube pressure test (step 722) and the device pressure test (step 740).

  FIG. 6C illustrates each step of the step 780 related to the systemization of the X-ray imaging system of the present invention.

  The systemization process 780 connects the system control device, the X-ray generation device, and the X-ray detection device so that the X-ray generation device and the X-ray detection device are integrated and controlled under the system control device. Process (step 760).

  Further, the systemization step 780 includes a step of connecting a display device to the system control device (762) and a step of connecting a storage device to the system control device (step 764).

  In the systematization step 780 of the present embodiment, it is possible to adjust the X-ray imaging conditions so that the “character” unique to each X-ray generation tube does not affect the imaging quality. (Step 770). According to this embodiment, it is possible to save time and effort for various adjustments related to the X-ray generation tube each time an image is taken. Therefore, the adjustment of the X-ray imaging system is speeded up, and the work load can be reduced.

  In the systematization step 780 of this embodiment, the system control device 202 outputs a captured image signal or a shooting condition signal to the display device 203 shown in FIG. 5, and the display device 203 displays the captured image or the shooting condition on the screen. Display. Such imaging conditions include information related to the X-ray generator tube 1 acquired based on the identification pattern portion. (Step 772) becomes possible. As a result, the operator of the X-ray imaging system can recognize information related to the X-ray generation tube without disassembling the X-ray generation apparatus.

  Further, in the systematization step 780 of the present embodiment, the system control device 202 issues a recording command to the recording device 209 shown in FIG. 5 based on the identification pattern portion, thereby recording information related to the X-ray generator tube. (Step 774) can be performed. As a result, the operator can read information related to the X-ray generation tube in association with the captured image without opening the X-ray generation device.

  The present invention includes a reflection type X-ray generator tube provided with a reflection type target.

DESCRIPTION OF SYMBOLS 1 X-ray generator tube 2 Insulation tube 4 Cathode 4b Electron emission part 5 Anode 5b Target 7 Identification pattern part

Claims (17)

An insulating tube, a cathode connected to one end of the insulating tube in the tube axis direction and provided with an electron emission portion, and an anode provided with a target connected to the other end of the insulating tube and emitting X-rays by electron irradiation. X-ray generator tube,
An X-ray generating tube, wherein an identification pattern portion is provided on an outer periphery of the insulating tube, and the identification pattern portion has a higher sheet resistance than the insulating tube.   The X-ray generating tube according to claim 1, wherein the sheet resistance of the identification pattern portion is 10 times or more of the sheet resistance of the insulating tube. The X-ray generating tube according to claim 1, wherein the sheet resistance of the identification pattern portion is 1 × 10 ¹⁶ Ω / □ or more.   The X-ray generator tube according to any one of claims 1 to 3, wherein the identification pattern portion is encoded information related to the X-ray generator tube.   5. The information includes at least one of a date, a time, a model number, a lot number, a serial number, a manufacturing apparatus, a manufacturing factory, an inspection apparatus, and an inspector related to the manufacture of the X-ray generation tube. X-ray generator tube described in 1.   The X-ray generating tube according to claim 1, wherein the identification pattern portion is a position reference in a tube circumferential direction.   The X-ray generator tube according to claim 1, wherein the identification pattern portion includes a pattern that can be identified by an optical sensor or an electrostatic field sensor.   The X-ray generating tube according to any one of claims 1 to 7, wherein the identification pattern portion is at least one of a one-dimensional bar code, a two-dimensional pattern code, and a text pattern. The X-ray generator tube according to any one of claims 1 to 8,
An X-ray generator having a drive circuit for driving the X-ray generator tube. The drive circuit includes a tube voltage circuit that applies a tube voltage between the cathode and the anode,
The X-ray generator according to claim 9, wherein the tube voltage circuit is adjusted based on the identification pattern unit and driven by the adjusted tube voltage. The drive circuit includes a cathode control circuit that controls the amount of electron emission from the electron emission unit,
11. The X-ray generator according to claim 9, wherein the cathode control circuit is adjusted based on the identification pattern portion and is driven with the adjusted electron emission amount.   The X-ray generation apparatus according to claim 9, further comprising an identification sensor that identifies the identification pattern portion. The X-ray generator according to any one of claims 9 to 12,
An X-ray detector that detects X-rays generated from the X-ray generator and transmitted through the subject;
A system controller for controlling the X-ray generator and the X-ray detector in an integrated manner;
An X-ray imaging system comprising:
The X-ray imaging system characterized in that the system control device adjusts imaging conditions based on the identification pattern portion. A photographic image signal or a photographic condition signal output from the system control device is input, and further includes a display device that displays the photographic image or the photographing condition,
The X-ray imaging system according to claim 13, wherein the system control device displays information related to the X-ray generation tube on the display device based on the identification pattern unit. An X-ray generating tube having an insulating tube;
A method of adjusting an X-ray generator having a drive circuit for driving the X-ray generator tube,
The X-ray generation tube has an identification pattern portion in which information on the X-ray generation tube is encoded on the insulating tube,
The identification pattern portion has a higher sheet resistance than the insulating tube,
A method for adjusting an X-ray generator, wherein the driving condition of the driving circuit is adjusted based on the identification pattern portion. The X-ray generation tube has an electron emission portion and a target that generates X-rays by electrons emitted from the electron emission portion,
The drive circuit has a cathode control circuit that controls the amount of electron emission from the electron emission unit,
16. The method of adjusting an X-ray generator according to claim 15, wherein the driving condition is the electron emission amount adjusted based on the identification pattern portion. The drive circuit includes a tube voltage circuit that applies a tube voltage between the electron emission unit and the target,
The method of adjusting an X-ray generation apparatus according to claim 15, wherein the driving condition is an upper limit of the tube voltage set based on the identification pattern unit.

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