JP4987321B2 - X-ray inspection apparatus and X-ray inspection method - Google Patents

Description

  The present invention relates to an X-ray inspection apparatus and an X-ray inspection method.

  In general, an X-ray inspection apparatus performs an inspection based on transmission images of the inside and surface of a subject by X-rays transmitted through the subject.

Such an X-ray inspection apparatus includes an X-ray source that generates X-rays and an X-ray two-dimensional detector such as an X-ray film, an X-ray image intensifier, or an X-ray CCD camera. Some obtain a transmission image of a specimen. Further, as a special X-ray inspection apparatus, X-rays from an X-ray source are irradiated on the subject surface, and fluorescent X-rays or scattered X-rays emitted from the subject surface are two-dimensionally detected to detect elements on the subject surface. Some perform distribution analysis (see, for example, Patent Documents 1 and 2).
JP 2000-55842 A JP 2003-329622 A

  In X-ray inspection equipment, when a surface of a metal plate with a thickness of several tens of centimeters is inspected with a spatial resolution of about 10 μm, high-energy and high-intensity X-rays are generated from an X-ray focal point of 10 μm or less in X-ray transmission inspection. X-ray source is required. In such a case, electrons with a high power density are absorbed by the metal target that generates X-rays in the X-ray source, so that there is a problem with the durability of the metal target against thermal shock, which is difficult to realize. Therefore, it has been a problem that the X-ray intensity and the spatial resolution necessary for the inspection cannot be compatible.

  In addition, in an inspection apparatus that uses fluorescent X-rays or scattered X-rays, the shape and size of the X-ray source are limited, so that there is a limit to the intensity and number of X-ray sources that can be used, and irradiation to the surface of the subject is performed. X-ray intensity is limited. Along with this, the fluorescence and scattered X-ray intensity are also limited. For this reason, the point that it was difficult to ensure the X-ray intensity required for detection was a problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to make it possible to inspect the surface shape of a subject with high spatial resolution using X-rays.

In order to solve the above-mentioned object, in the X-ray inspection apparatus, the present invention provides a vacuum vessel, a plurality of ring-shaped electron emitters that emit electrons stored in the vacuum vessel, and a predetermined amount emitted from the electron emitter. When the electrons accelerated by the voltage of the electron beam collide with a predetermined electron collision region, X-rays emitted toward a predetermined X-ray irradiation region are emitted, stored in the vacuum vessel, and each of the plurality of ring-shaped electron emitters A plurality of provided ring-shaped X-ray targets and X-rays emitted from the subject when the subject placed in the X-ray irradiation region is irradiated with the X-rays emitted from the X-ray target. There the reflected X-ray collimator for passing an X-ray two-dimensional detector for detecting the X-rays having passed through the reflective X-ray collimator, the electron emitter and each said predetermined voltage to the pair of the X-ray target Applied to, with a mutually time difference to the plurality of ring-shaped electron emitter possess a power source for pulsed release of the electrons, respectively, wherein the plurality of ring-shaped electron emitters and the plurality of ring-shaped X-ray The target is arranged around the cylindrical axis of the vacuum vessel .

Further, the present invention provides an X-ray inspection method in which electrons are emitted in a pulsed manner sequentially from a plurality of ring-shaped electron emitters centered on a cylindrical axis of a vacuum vessel, and the electron emission step releases the electrons. An electron acceleration step of accelerating the electrons at a predetermined voltage, and the electrons accelerated in the electron acceleration step are provided around the cylindrical axis of the vacuum vessel corresponding to the plurality of ring-shaped electron emitters, respectively. An X-ray emission process for colliding with a plurality of ring-shaped X-ray targets to emit X-rays toward a predetermined X-ray irradiation area, and the X-rays emitted in the X-ray emission process are arranged in the X-ray irradiation area An irradiation step of irradiating the subject, a collimation step of collimating X-rays emitted from the subject in a predetermined direction by a reflection X-ray collimator, and collimation in the predetermined direction in the collimation step And having an X-ray two-dimensional detection step of detecting a over bets X-ray, a.

  According to the present invention, the surface shape of a subject can be examined with high spatial resolution by X-rays.

  An embodiment of an X-ray inspection apparatus according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or similar structure, and the overlapping description is abbreviate | omitted.

[Embodiment 1]
1A and 1B show an X-ray inspection apparatus according to Embodiment 1 of the present invention, in which FIG. 1A is a partially sectional perspective view, and FIG. 1B is a longitudinal sectional view.

  The X-ray inspection apparatus includes an X-ray source 1, a collimator 2, an X-ray two-dimensional detector 3 and a shield 4.

  The X-ray source 1 has a vacuum vessel 5. The vacuum vessel 5 has a cylindrical outer cylinder 5a, a cylindrical inner cylinder 5b having a smaller diameter than the outer cylinder 5a and having the same axis as the cylinder 5a, and a donut shape connecting the bottoms of the outer cylinder 5a and the inner cylinder 5b. A vacuum space surrounded by the two discs 5c. Inside the vacuum vessel 5, a ring-shaped electron emitter 6 and a ring-shaped X-ray target 7 are accommodated. Both the electron emitter 6 and the X-ray target 7 are arranged around the cylindrical axis of the vacuum vessel 5 at a predetermined interval in the cylindrical axis direction. One surface of the X-ray target 7 is a part of a conical surface centering on the cylindrical axis of the vacuum vessel 5. The X-ray target 7 is disposed in the vicinity of the disk 5c.

  An incident X-ray collimator 10 that transmits X-rays only within a circle centered on the cylindrical axis of the vacuum vessel 5 is provided in the vicinity of the disc 5c. Further, a part of the vacuum vessel 5 is covered with the shield 4 so that X-rays are not emitted to portions other than the incident X-ray collimator 10.

  A power source 20 is connected to the electron emitter 6 via a high voltage line 13 so that a negative potential can be applied to the X-ray target 7.

  Inside the inner cylinder 5b, the reflective X-ray collimator 2 is disposed at a position where the cylindrical axis direction of the vacuum vessel 5 is substantially the same as that of the disk 5c. An X-ray two-dimensional detector 3 is disposed above the X-ray two-dimensional detector 3. The X-ray two-dimensional detector 3 is connected to an external monitor 21 or the like via an image signal line 14.

  When the electrons 8 are emitted in a ring shape from the electron emitter 6, the electrons 8 are accelerated by the voltage applied between the electron emitter 6 and the X-ray target 7 and collide with the X-ray target 7. X-rays 9 are generated when the accelerated electrons 8 collide with the X-ray target 7.

  The X-ray 9 generated from the X-ray target 7 passes through the incident X-ray collimator 10 and is irradiated onto the X-ray irradiation surface 11 at a position facing the disk 5c. At this time, the X-ray 9 irradiated to the X-ray irradiation surface 11 has a high irradiation X-ray intensity because X-rays generated from each point of the ring-shaped target 7 concentrate on the X-ray irradiation surface 11. Further, if the electrons 8 collide with the entire ring-shaped X-ray target 7, the thermal shock per unit area received by the X-ray target 7 can be reduced. For this reason, the total number of electrons 8 generated from the ring-shaped emitter 6 can be increased, and the generated X-ray intensity can be further increased.

  Scattering and fluorescent X-rays 12 are generated from the X-ray irradiation surface 11 irradiated with X-rays, and only the scattered and fluorescent X-rays 12 that have passed through the reflective X-ray collimator 2 enter the X-ray two-dimensional detector 3. , Detected as an X-ray signal. At this time, the intensity of the scattered X-rays and fluorescent X-rays 12 incident on the X-ray two-dimensional detector 3 changes depending on the surface state of the X-ray irradiation surface 11 such as irregularities. For this reason, when the X-ray signal detected by the X-ray two-dimensional detector 3 is imaged, the surface state of the X-ray irradiation surface 11 such as irregularities can be observed.

  Since the spatial resolution of the surface state change depends on the hole diameter of the collimator 2, the hole diameter of the collimator 2 is reduced when performing a high-resolution inspection. When the hole diameter of the collimator 2 is reduced, the X-ray dose passing through the collimator 2 is reduced and the detection sensitivity is lowered. Therefore, it is necessary to increase the intensity of irradiated X-rays in order to perform a high-resolution and high-sensitivity inspection.

  According to the present embodiment, since the ring-shaped X-ray target 7 is used, the irradiation X-ray intensity can be increased without increasing the thermal load of the X-ray target, and high-resolution and high-sensitivity surface inspection can be performed. .

  The X-ray target 7 and the electron emitter 6 may have shapes other than the ring shape as long as the thermal shock per unit area received by the X-ray target 7 can be reduced.

[Embodiment 2]
2A and 2B are X-ray inspection apparatuses according to the second embodiment of the present invention, in which FIG. 2A is a partially sectional perspective view, and FIG. 2B is a longitudinal sectional view.

  The X-ray inspection apparatus of this embodiment includes a plurality of sets of ring-shaped emitters 6 and ring-shaped X-ray targets 7. A time difference is given to the electron emission from the plurality of ring-shaped electron emitters 6, and the electron emission from one electron emitter 6 is pulsed. For this reason, the thermal shock of the ring-shaped X-ray target 7 that receives the emitted electrons 8 also becomes pulsed. Therefore, the average heat input of the X-ray target 7 becomes low. For this reason, it is possible to increase the total number of electrons 8 generated in a pulsed manner, and the irradiation X-ray intensity can be increased.

  As described above, since the irradiation X-ray intensity can be increased by the X-ray inspection apparatus of the present embodiment, a high-resolution and high-sensitivity surface inspection can be performed.

[Embodiment 3]
3A and 3B are X-ray inspection apparatuses according to Embodiment 3 of the present invention, in which FIG. 3A is a partially sectional perspective view, and FIG. 3B is a longitudinal sectional view.

  The X-ray inspection apparatus of the present embodiment uses a pinhole collimator 15 instead of the reflection X-ray collimator of the first embodiment. The X-ray inspection apparatus of this embodiment is the same as a pinhole camera having the X-ray irradiation surface 11 as an object surface and the X-ray two-dimensional detector 3 as an image surface, and a surface two-dimensional inspection with a simple configuration. Is possible.

[Embodiment 4]
4A and 4B are X-ray inspection apparatuses according to Embodiment 4 of the present invention, in which FIG. 4A is a partially sectional perspective view, and FIG. 4B is a longitudinal sectional view.

  The X-ray inspection apparatus of this embodiment is obtained by adding a drive mechanism 16 that moves the position of the pinhole collimator 15 to the X-ray inspection apparatus of Embodiment 3. The drive mechanism 16 allows the pinhole collimator 15 to move in the axial direction from the X-ray irradiation surface 11 toward the X-ray two-dimensional detector 3.

  FIG. 5 is a schematic diagram showing the relationship between the position of the pinhole collimator 15 and the size of the image. With reference to the case where the pinhole collimator 15 is at the position shown in FIG. 5A, when the pinhole collimator 15 approaches the X-ray irradiation surface 11 (object surface) as shown in FIG. The image shown on the surface (image plane) on which the X-rays of the device 3 are incident becomes large. On the contrary, when the pinhole collimator 15 approaches the X-ray two-dimensional detector 3 as shown in FIG. 5C, the image reflected on the surface of the X-ray two-dimensional detector 3 on which the X-rays are incident becomes small.

  In the X-ray inspection apparatus of the present embodiment, the ratio of the distance from the object surface to the pinhole collimator 15 and the distance from the pinhole collimator 15 to the image plane changes by changing the position of the pinhole collimator 15. That is, the surface image of the detected X-ray irradiation surface 11 can be enlarged or reduced.

[Embodiment 5]
FIG. 6 is a cross-sectional view of the X-ray inspection apparatus according to the fifth embodiment of the present invention.

  The X-ray inspection apparatus of the present embodiment uses a tapered collimator 19 instead of the pinhole collimator 15 of the third embodiment and the X-ray inspection apparatus. The tapered collimator 19 has a predetermined thickness in the direction in which the scattered and fluorescent X-rays 12 pass, and a cone having the same axis is coupled at the apex portion to the portion through which the scattered and fluorescent X-rays 12 pass. A hole of shape penetrates.

  FIG. 7 is a cross-sectional view schematically showing the relationship between the shape of the collimator and collimated X-rays and leakage X-rays.

  The spatial resolution of surface condition inspection is determined by the hole diameter of the collimator. As shown in FIG. 7A, when a thin plate thickness collimator 17 having a through hole in a thin plate is used as a collimator, X-rays cannot be sufficiently shielded if the X-ray intensity is high. There is. In this case, the spatial resolution depending on the hole diameter of the collimator cannot be ensured. Further, as shown in FIG. 7B, when a thick collimator 18 having a thick plate thickness with a constant collimator hole diameter is used, even necessary X-rays are shielded, and the detection sensitivity is lowered.

  In the X-ray inspection apparatus of the present embodiment, the collimator can be made thicker while allowing necessary X-rays to pass therethrough by forming the penetrating portion of the collimator into a tapered shape as shown in FIG. 7C. . For this reason, unnecessary leakage X-rays can be shielded and only X-rays necessary for inspection can be detected, and high-resolution and high-sensitivity inspection can be performed.

  The above description is merely an example, and the present invention is not limited to the above-described embodiments, and can be implemented in various forms.

BRIEF DESCRIPTION OF THE DRAWINGS It is the X-ray inspection apparatus of Embodiment 1 which concerns on this invention, Comprising: (a) is a partial cross section perspective view, (b) is a longitudinal cross-sectional view. It is the X-ray inspection apparatus of Embodiment 2 which concerns on this invention, Comprising: (a) is a partial cross section perspective view, (b) is a longitudinal cross-sectional view. It is the X-ray inspection apparatus of Embodiment 3 which concerns on this invention, Comprising: (a) is a partial cross section perspective view, (b) is a longitudinal cross-sectional view. It is the X-ray inspection apparatus of Embodiment 4 which concerns on this invention, Comprising: (a) is a partial cross section perspective view, (b) is a longitudinal cross-sectional view. The schematic diagram which shows the relationship between the position of a pinhole collimator, and the magnitude | size of an image. The longitudinal cross-sectional view of the X-ray inspection apparatus of Embodiment 5 which concerns on this invention. Sectional drawing which shows typically the relationship between the shape of a collimator, the collimated X-ray | X_line, and leakage X-ray | X_line.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... X-ray source, 2 ... Collimator, 3 ... X-ray two-dimensional detector, 4 ... Shielding body, 5 ... Vacuum container, 5a ... Outer cylinder, 5b ... Inner cylinder, 5c ... Disc, 6 ... Electron emitter, 7 ... X-ray target, 8 ... electron, 9 ... X-ray, 10 ... incident X-ray collimator, 11 ... X-ray irradiated surface, 12 ... scattered and fluorescent X-ray, 13 ... high voltage line, 14 ... image signal line, 15 DESCRIPTION OF SYMBOLS ... Pinhole collimator, 16 ... Pinhole collimator drive mechanism, 17 ... Thin plate thickness collimator, 18 ... Thick plate thickness collimator, 19 ... Tapered collimator, 20 ... Power supply, 21 ... External monitor

Claims (6)

A vacuum vessel;
A plurality of ring-shaped electron emitters that emit electrons, housed in the vacuum vessel;
When the electrons emitted from the electron emitter and accelerated at a predetermined voltage collide with a predetermined electron collision region, the X-rays are emitted to a predetermined X-ray irradiation region and are stored in the vacuum vessel, and the plurality of ring shapes A plurality of ring-shaped X-ray targets provided for each of the electron emitters;
A reflective X-ray collimator through which X-rays emitted from the subject pass when X-rays emitted from the X-ray target are irradiated on the subject arranged in the X-ray irradiation region;
And X-ray two-dimensional detector for detecting the X-rays having passed through the reflective X-ray collimator,
A power source that applies the predetermined voltage to each of the pair of the electron emitter and the X-ray target, and causes the plurality of ring-shaped electron emitters to emit electrons in a pulsed manner with a time difference from each other;
Have a, the plurality of ring-shaped electron emitter and the plurality of ring-shaped X-ray target of, X-ray inspection apparatus characterized by being arranged around the cylindrical axis of the vacuum vessel. The reflected X-ray collimator, wherein the X-ray two-dimensional detector and the opposite direction the thickness direction of the plate to the plate surface thickness that fully shield the X-rays incident on of the subject side as an axis X-ray examination apparatus as claimed in claim 1, wherein the headed spreads two conical is provided with a pin hole of the bound shape. The X-ray inspection apparatus according to claim 2, further comprising a collimator driving unit that moves the reflection X-ray collimator. An electron emission step of emitting electrons sequentially from a plurality of ring-shaped electron emitters around the cylindrical axis of the vacuum vessel ; and
An electron acceleration step of accelerating the electrons emitted in the electron emission step at a predetermined voltage;
Electrons accelerated in the electron accelerating step are caused to collide with a plurality of ring-shaped X-ray targets provided around the cylindrical axis of the vacuum vessel corresponding to the plurality of ring-shaped electron emitters, respectively. An X-ray emission process for emitting X-rays toward the X-ray irradiation region;
An irradiation step of irradiating the subject arranged in the X-ray irradiation region with the X-rays emitted in the X-ray emission step;
A collimating step of collimating X-rays emitted from the subject in a predetermined direction by a reflective X-ray collimator;
And X-ray two-dimensional detection step of detecting the X-rays collimated in the predetermined direction by the collimating step,
An X-ray inspection method characterized by comprising: The reflected X-ray collimator, the plate thickness direction of the plate to the plate surface thickness that fully shield the incident X-rays of the subject side as the axis X-ray two-dimensional detector and the opposite direction The X-ray inspection method according to claim 4 , wherein a pinhole having a shape in which two conical shapes extending toward the surface are combined is provided. Claim 4 or claim 5 X-ray inspection method according to further comprising the step of moving the reflected X-ray collimator.

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