JPH0675042B2 - X-ray tomography system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to an X-ray tomography apparatus using a microfocus X-ray generator as an X-ray source.

(Prior Art) Generally, as an X-ray source of an X-ray tomographic imaging apparatus, a high voltage is applied to accelerate thermoelectrons generated in a tube, and the thermoelectrons are applied to a target composed of tungsten or the like, An X-ray generator that generates X-rays from the target by bremsstrahlung is used.

In such an X-ray tomographic imaging apparatus, it is important to accurately adjust the focus position of the X-ray generation apparatus to a predetermined position. This is because if there is a deviation in this position, blurring or artifacts (false images) will occur in the tomographic image.

By the way, an X commonly used in an X-ray tomographic imaging apparatus is used.
The focal dimension of the line generator is about 1/10 to 1 mm. Therefore, the temporal variation of the size and position of the focus itself is
Usually not a problem.

However, recently, when the object to be inspected is ceramics or the like, there is a strong demand that an X-ray tomographic imaging apparatus detects a defect of up to several tens of μm.

Therefore, in order to reduce the focus size of the X-ray generator to about the size of the defect to be detected or to be smaller than that, the micro-focus X-ray generator capable of detecting the minute defect of the above degree by increasing the magnification of imaging. Can be used.

However, in the microfocus X-ray generator,
Since the electron beam applied to the target is focused extremely finely, the size and position of the focal point temporally fluctuates to the same or more than the focal point size (several to several tens μm) of itself. Therefore, the size and position of the focal point must be adjusted more than necessary, resulting in a problem of requiring a great deal of time and labor.

(Problems to be Solved by the Invention) That is, when the microfocus X-ray generator is used in an X-ray tomographic imaging apparatus, the microfocus X-ray generator is simply the same as a conventional general X-ray generator. When used, it is extremely difficult to confirm or adjust the size and position of the focal point. On the other hand, if the size and position of the focal point remain uncertain, it cannot be practically used as an X-ray tomographic imaging apparatus.

The reason is as follows.

(1) Generally, the X-ray detector of the X-ray tomographic imaging apparatus is a one-dimensionally arranged multi-channel detector, and therefore, there is a possibility that the size and position of the focal point in the channel direction can be measured. It is not possible to measure the size and position of the focus in the slice direction of the line.

(2) In general, an X-ray tomography apparatus can output the tomographic line or the result of data collection after collecting data for one scan (one tomography), and thus measures the size and position of the focal point. Each time it takes several seconds to several hundreds of seconds to optimize the size and position of the focal point, even if only ten measurements are required, it will take several minutes to several tens of minutes even if only the channel direction is completed. It is not practical.

(3) In addition, the confirmation and adjustment of the size and position of the focal point in (2) above are performed by at least the micro focus X.
It is necessary every time the power of the line generator is turned on.

(4) It is technically difficult to maintain the size and position of the focal point of the microfocus X-ray generator with the reproducibility of about 1 μm and the long-term stability required for the X-ray tomography apparatus. Considered impossible for the time being.

The present invention has been made based on such circumstances, and an X-ray tomographic imaging apparatus capable of easily confirming or adjusting the size and position of the focal point of X-rays emitted from the microfocus X-ray generator. The purpose is to provide.

[Structure of the Invention] (Means for Solving the Problems) An X-ray tomographic imaging apparatus of the present invention is a microfocus X-ray generator for generating X-rays, and an object to be inspected for inspecting an internal state by the X-rays. An object is placed between the microfocus X-ray generation device and the sample stage, and the X-rays emitted from the microfocus X-ray generation device are made into a parallel bundle and installed on the sample stage. A collimator for irradiating the inspected object, a first X-ray detector for detecting the amount of X-rays transmitted through the inspected object, and a focus of X-rays emitted from the microfocus X-ray generator. A second X-ray detector for confirming the size and position, and X-rays emitted from the microfocus X-ray generator for the first X-ray detector side or the second X-ray detector. Irradiate on either side So therefore, those having a moving mechanism for relatively moving said microfocus X-ray generator and said first X-ray detector and the second X-ray detector.

(Operation) In the present invention, since an independent second X-ray detector is provided as a means for confirming the size and position of the focus of X-rays emitted from the microfocus X-ray generator, It is possible to easily confirm or adjust the size and position of the focus of X-rays emitted from the microfocus X-ray generator.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 is a view showing the arrangement of an X-ray tomographic imaging apparatus according to an embodiment of the present invention.

In the figure, 1 is a microfocus X-ray generator for generating X-rays, 2 is a sample stage on which an object to be inspected 3 such as ceramics whose internal state is inspected by the X-rays is installed, and 4 is a microfocus X-ray. A collimator 5 for collimating the X-rays emitted from the ray generator 1 and irradiating the object 3 to be inspected is a multi-channel X-ray detector for detecting the amount of X-rays passing through the object to be inspected and passing through the collimator 6. is there.

Reference numeral 7 is for confirming the size and position of the focal point of the X-ray emitted from the microfocus X-ray generator 1.
X-ray I, I (image intensifier), X-ray imaging unit that can take X-rays in real time, such as X-ray vidicon, 8
Uses a micro-focus X-ray generator 1 for multi-channel X
The X-ray generator moving gantry accurately moves the X-ray detector 5 side (hereinafter, referred to as a tomographic image capturing position) or the X-ray imaging unit 7 side (hereinafter, referred to as a focus monitor position).

A high voltage generator 9 that generates a high voltage is connected to the microfocus X-ray generator 1. An X-ray controller 10 for controlling the microfocus X-ray generator 1 and the high voltage generator 9 is connected to them.

Data concerning the amount of X-rays obtained by the multi-channel X-ray detector 5 is collected by the data collecting device 11 and sent to the computer 12. The computer 12 performs a predetermined calculation, and the calculation result is displayed on the CRT 13.

The sample table 2 is equipped with a movable mechanism for changing the angle and position of the X-rays irradiated on the inspection object 3, and this movable mechanism is controlled by the mechanism controller 14.

The computer 12 and the mechanism control device 14 are connected to a system control device 15 that controls the timing of the entire system.

The X-ray generator moving base 8 is configured so that the microfocus X-ray generator 1 can be stopped and fixed accurately at the tomographic image capturing position and the focus monitor position with an error of, for example, about 1/10 of the focus size. Further, the opening at the focus monitor position of the X-ray generator moving base 8 is made of a material such as Au which is thin and has a large absorption coefficient for X-rays. For example, as shown in FIG. It is blocked by a focus confirmation jig 16 which is cut in directions parallel and perpendicular to the plane.

A display device 17 such as a CRT that displays a signal from the X-ray imaging unit 7 as an image is connected to the X-ray imaging unit 7.

In FIG. 1, 18 is the focus of the microfocus X-ray generator 1 when a tomographic image is taken, and 19 is the microfocus X-ray generator 1 moved to the focus monitor position to confirm and adjust the focus position. This is the focus of the microfocus X-ray generator 1 in the case.

Next, the operation of the X-ray tomographic imaging apparatus configured as described above will be described.

First, the microfocus X-ray generator 1 is moved so that its focus is at the 19th position (focus monitor position).

The image of the focus confirmation jig 16 is magnified and displayed on the X-ray imaging unit 7, and is displayed on the display device 17 in real time. And
With the focus adjustment function of the X-ray controller 10, a focus adjustment jig
The 16 images are adjusted so that they are reflected at a predetermined position on the display device 17 with a predetermined blur.

Here, the size and position of the focal point of the microfocus X-ray generator 1 are adjusted to the determined optimum value.

Next, the focus of the microfocus X-ray generator 1 is changed.
Move to position 18 (tomographic image shooting position)
Generate a line. As for this X-ray, the X-ray of only a desired transmission path is converted by the collimator 4 and the collimator 6 into the X-ray detector 5.
Is collimated to be incident on.

The inspection object 3 installed on the sample table 2 is placed on the X-ray transmission path, and the inspection object 3 is irradiated with X-rays from a desired angle and position of the inspection object 3 by the movement of the sample table 2.
Is positioned.

Here, in the case of the X-ray tomographic imaging apparatus of the second generation, the sample table 2 is scanned by traverse and rotation, and data is collected as much as necessary for imaging one tomographic image.

Then, the electric signal obtained from the X-ray detector 5 is subjected to processing such as integration and A / D conversion by the data collection device 11, and then sent to the computer 12. The computer 12 performs an operation for reconstructing a tomographic image, and the result is displayed on the CRT 13.

As described above, in the present embodiment, the size and position of the focus of the microfocus X-ray generator 1 may be adjusted in advance to a desired optimum value at the focus monitor position. The size and position of the focal point of No. 1 can be easily confirmed or adjusted.

It should be noted that such confirmation or adjustment of the size and position of the focal point of the microfocus X-ray generator 1 is performed not only at the initial stage but also at an appropriate time during use according to the performance of the microfocus X-ray generator 1. You may make it implement.

Next, another embodiment of the present invention will be described.

FIG. 3 is a view showing the arrangement of an X-ray tomographic imaging apparatus according to another embodiment of the present invention.

This device shown in the figure is used as an X-ray imaging unit for X-rays I, I20, T
Display device 1 using V camera 21 and camera controller 22
CRT23 is used as 6.

Then, the image of the focus confirmation jig 16 by the X-rays emitted from the micro-focus X-ray generator 1 placed at the focus monitor position is incident on the X-rays I and I20 and becomes an image of visible light, which is a TV image.
The image is taken by the camera 21 and displayed on the CRT 23. The camera controller 22 controls the raster scan of the TV camera 21.

Here, the X-rays I and I20 have a large diameter of about 150 mm even if the incident surface has a small diameter of 6 inches, so even if the X-ray focus is slightly deviated, the image of the focus adjustment jig 16 Practical without losing sight.

In addition, as shown in FIG.
Since several thin slits with a specified pitch are provided in each direction parallel and perpendicular to the slice plane of X-ray, CR
On T23, the size and position of the focal point can be simultaneously adjusted in real time in two directions parallel and perpendicular to the slice plane.

Although the microfocus X-ray generator 1 is moved in the above embodiment, the position of the microfocus X-ray generator 1 is always fixed and the X-ray detector 5 and the X-rays I, I20 and T are fixed.
V camera 21 and may move. In this case, a tool corresponding to the focus confirmation jig 16 is fixed to the center of the sample table 3. In this case, since the image of the focus confirmation jig 16 can be adjusted at the enlarged position, it is easy to improve the accuracy of focus adjustment, and the microfocus X-ray generator 1 is provided.
There is also an effect that vibration is not applied to the present device because it does not move.

As described above, according to the present invention, as a means for confirming the size and position of the focal point of the X-ray emitted from the microfocus X-ray generator, an independent second X-ray is used. Since the detector is provided, it is possible to easily confirm or adjust the size and position of the focal point of the X-ray emitted from the microfocus X-ray generator.

That is, the focus adjustment of the micro-focus X-ray generator that requires specifically confirming or adjusting the size and position of the focus by the second X-ray detector is performed at the same time in the directions parallel and perpendicular to the slice plane. Can be done in real time. Therefore, the time required for this adjustment is about several tens of seconds, and the time required is 1/100 of that required when the present invention is not carried out.
You can save about 100.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an X-ray tomographic imaging apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a focus confirmation jig, and FIG.
The figure is a diagram showing the configuration of an X-ray tomographic imaging apparatus according to another embodiment of the present invention. 1 ... Microfocus X-ray generator, 2 ... Sample stage, 3 ... Inspection object, 4,6 ... Collimator, 5 ... Multi-channel X-ray detector, 7 ... X-ray imaging unit, 8 ... … X-ray generator mobile stand, 9 …… High voltage generator, 10 …… X-ray controller, 11 …… Data collector, 12 …… Computer, 13…
… CRT, 14 …… Mechanism control device, 15 …… System control device, 16 …… Focus confirmation jig, 17 …… Display device.

Claims (1)

[Claims] 1. A microfocus X-ray generator for generating X-rays, a sample stage on which an object to be inspected whose internal state is inspected by the X-rays is installed, and the microfocus X-ray.
A collimator, which is arranged between the beam generator and the sample stage, forms a parallel bundle of X-rays emitted from the microfocus X-ray generator, and irradiates an object to be inspected installed on the sample stage, and the collimator. A first X-ray detector for detecting the amount of X-rays transmitted through an inspection object, and a second X-ray for confirming the size and position of the focal point of X-rays emitted from the microfocus X-ray generator. In order to irradiate either the first X-ray detector side or the second X-ray detector side with X-rays emitted from a line detector and the microfocus X-ray generator, the microfocus An X-ray tomographic imaging apparatus comprising: an X-ray generator and a moving mechanism that relatively moves the first X-ray detector and the second X-ray detector.