JPH02138854A - X-ray tomograph - Google Patents

Abstract

PURPOSE:To adjust the focus of a microfocus X-ray generating apparatus in directions parallel and vertical to a slice plane simultaneously in a real time by providing a second independent detector which checks up the size and the position of the focus of an X-ray emitted from the X-ray generating apparatus. CONSTITUTION:An X-ray is generated by a microfocus X-ray generating apparatus 1 of an X-ray tomograph and the inspection of the internal state of a substance 3 to be inspected, which is set on a sample table 2, is executed by this X-ray. A collimator 4 is disposed between this apparatus 1 and the sample table 2 and thereby the X-ray emitted from the apparatus 1 is turned to be a parallel flux and applied to the substance 3 to be inspected. Besides, the amount of the X-ray transmitted through the substance 3 is detected by a multichannel X-ray detector 5 and the data on the amount of the X-ray from this detector 5 are collected by a data collecting device 11 and sent to a computer 12. An X-ray generating apparatus moving frame 8 for changing the angle and the position of the X-ray applied to the substance 3 is disposed for said sample table 2, and the size and the position of the focus of the X-ray are checked up by an X-ray image sensing element 7.

Description

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

(Prior Art) In general, as an X-ray source for an X-ray tomography device, a high voltage is applied and thermoelectrons generated in the tube are accelerated by this high voltage and applied to a target made of tungsten or the like. An X-ray generator is used that generates X-rays from the target by bremsstrahlung radiation.

In such an X-ray tomography apparatus, it is important to accurately align the focal position of the X-ray generator to a predetermined position. This is because if there is a shift in this position, blurring or artifacts (false images) will occur in the tomographic image.

By the way, the X
The focal size of the line generator is approximately 1710-1 mm. Therefore, temporal variations in the size and position of this focus itself are usually not a problem.

However, recently, when the object to be inspected is ceramics, etc., defects up to several tens of micrometers can be detected using X-rays. If the X-ray generator is used in the same way as a conventional general X-ray generator, 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 used practically as an X-ray tomographic imaging apparatus.

It is conceivable to use a microfocus X-ray generator that enables detection of minute defects.

However, with the microfocus X-ray generator,
In order to focus the electron beam that hits the target extremely narrowly, the size and position of the focal spot vary over time to a degree that is equal to or greater than the size of the focal spot itself (several to several tens of μm).

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 effort.

(Problem to be Solved by the Invention) Although it is possible to determine the size and position of the focal point in the slice direction of X-rays, it is not possible to measure the size and position of the focal point in the slice direction of X-rays.

(2) In general, X-ray tomography equipment can output tomograms or data collection results after collecting data for a scan (one time of tomography), so the size and position of the focal point can be measured. If you try to do this, it will take several seconds to several hundreds of seconds each time, and it takes 1 to 100 seconds to optimize the size and position of the focus
Even if only the channel direction is completed with zero millimeter settings, it will take several minutes to several tens of minutes, which is not practical.

(3) Moreover, the confirmation or adjustment of the size and position of the focal point in (2) above is performed at least with the Micro Focus X
It is required every time the line generator is powered on.

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

It is an object of the present invention to provide a method that has been made in view of these circumstances.

[Structure of the Invention] (Means for Solving the Problems) The X-ray tomography apparatus of the present invention includes a microfocus X-ray generator that generates X-rays, and an object to be inspected whose internal state is inspected using the X-rays. It is arranged between a sample stage on which an object is installed, the microfocus X-ray generator, and the sample stage, and the X-rays emitted from the microfocus X-ray generator are made into a parallel bundle, and the X-rays are set on the sample stage. a collimator that irradiates the inspected object, a first X-ray detector that detects the amount of X-rays that have passed through the inspected object, and a focal point of the X-rays emitted from the microfocus X-ray generator. a second X-ray detector for confirming the size and position; As a means for confirming a moving mechanism for relatively moving the microfocus X-ray generator, the first X-ray detector, and the second X-ray detector in order to irradiate one of the sides. Since the second independent X-ray detector is provided, it is possible to easily confirm or adjust the size and position of the focal point of the X-rays emitted from the microfocus X-ray generator.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing the configuration of an X-ray tomography apparatus according to an embodiment of the present invention.

In the figure, 1 is a microfocus X-ray generator that generates X-rays, 2 is a sample stage on which is placed an object 3 to be inspected, such as ceramics, whose internal state is inspected by the X-rays, and 4 is a microfocus X-ray generator. A collimator converts the X-rays emitted from the radiation generator 1 into a parallel beam and irradiates the object 3 to be inspected, and 5 is a multi-channel X-ray detector that detects the amount of X-rays that have passed through the object to be inspected and passed through the collimator 6. be.

7 is for confirming the size and position of the focal point of the X-rays emitted from the microfocus X-ray generator 1;
An X-ray imaging unit capable of photographing X-rays in real time such as X-ray I, I (Image Intensive Air), ) or the X-ray imaging unit 7 side (hereinafter referred to as the focus monitor position).
This is a moving platform for the X-ray generator that can be moved accurately to each location.

A high voltage generator 9 that generates a high voltage is connected to the microfocus X-ray generator 1 .

The microfocus X-ray generator 1 and the high voltage generator 9 are connected to an X-ray controller 10 that controls them.

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

The sample stage 2 is equipped with a movable mechanism for changing the angle and position of the X-rays irradiated onto the inspected object 3, and this movable mechanism is controlled by a mechanism control device 14.

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

The X-ray generator movable mount 8 is configured to be able to stop and fix the microfocus X-ray generator 1 accurately at the tomographic imaging position and the focus monitor position with an error of, for example, about 1/10 of the focus size. In addition, the X-ray generator moving stand 8
The aperture at the focal point monitor position is made by cutting thin slits in a thin material such as Au, which has a large absorption coefficient for X-rays, in parallel and perpendicular directions to the X-ray slice plane, for example, as shown in Figure 2. It is blocked by the focus confirmation jig 16.

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

In FIG. 1, 18 is the focal point of the microfocus X-ray generator 1 when taking a tomographic image, and 19 is a focus monitor for the microphone 0 focus X-ray generator 1 to confirm and adjust the focal position. This is the focal point of the microfocus X-ray generator 1 when it is moved to this position.

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

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

The image of the focus confirmation jig 16 is enlarged and reflected on the X-ray imaging unit 7, and displayed on the display device 17 in real time. Then, the focus adjustment function of the X-ray control device 10 adjusts the image of the focus adjustment jig 16 so that it appears 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 predetermined optimum values.

Next, move the microfocus X-ray generator 1 so that its focal point is at position 18 (tomographic imaging position),
Generates X-rays. The X-rays are collimated by the collimators 4 and 6 so that only the X-rays along a desired transmission path are incident on the X-ray detector 5.

The object to be inspected 3 placed on the sample stand 2 is placed on the X-ray transmission path, and the object to be inspected 3 is moved so that the X-rays are irradiated from the desired angle and position of the object to be inspected 3 by the movement of the sample stand 2.
positioning is performed.

Here, in the case of the second generation X-ray tomography apparatus, the sample stage 2 is scanned by traverse and rotation to collect data as much as is necessary for imaging one tomogram.

Then, the electrical signal obtained from the X-ray detector 5 is sent to the computer 12 after being subjected to processing such as integration and A/D conversion by the data acquisition device 11. The computer 12 performs calculations to reconstruct the tomographic image, and the results are displayed on the CRT 1.
3.

As described above, in this embodiment, the size and position of the focal point of the microfocus X-ray generator 1 may be adjusted in advance to a desired optimum value at the focus monitor position, so the microfocus X-ray generator The size and position of the focal point 1 can be easily confirmed or adjusted.

Note that the size and position of the focal point of the microfocus X-ray generator 1 should be checked or adjusted not only at the initial stage, but also at appropriate times during use depending on the performance of the microfocus X-ray generator 1. It may be implemented.

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

FIG. 3 is a diagram showing the configuration of an X-ray tomography apparatus according to another embodiment of the present invention.

This device shown in the same figure has X-ray 1, I2, and
0, using the TV right camera 1 and camera controller 22,
A CRT 23 is used as the display device 16.

The image of the focus confirmation jig 16 created by the X-rays irradiated from the microfocus X-ray generator 1 placed at the focus monitor position enters the X-rays 1,120 and becomes a visible light image on the TV right camera 1. The image is captured and displayed on the CRT 23. The camera controller 22 controls the rask scan of the TV right camera 1.

Here, the X-ray I, 120 has a large diameter of about 1.50 nm even if the aperture of the incident surface is a small 6-inch one, so even if the focus of the X-ray is slightly deviated by a large amount, the focus adjustment jig 16 It is practical because you don't lose sight of the image.

In addition, as shown in FIG. 2, the focus adjustment jig 16 is provided with several narrow slits at a predetermined pitch in directions parallel and perpendicular to the X-ray slice plane.
On the CRT 2B, the size and position of the focal point can be adjusted simultaneously in real time in two directions parallel and perpendicular to the slice plane.

In the above embodiment, the microfocus X-ray generator 1 was moved, but the position of the microfocus X-ray generator 1 was always fixed, and the X-ray detector 5 and the X-ray I, 120
and the TV right camera 1 may be moved. In this case, something equivalent to the focus confirmation jig 16 is fixed to the center of the sample stage 3.

In this case, since the image of the focus confirmation jig 16 can be adjusted at a magnified position, it is easy to improve the precision of focus adjustment, and the microfocus X-ray generator 1 is not moved, so the present device Another effect is that no vibration is applied to the

[Effects of the Invention] As explained above, according to the present invention, as a means for confirming the size and position of the focal point of the X-rays emitted from the microfocus X-ray generator, Since the detector is provided, it is possible to easily confirm or adjust the size and position of the focal point of the X-rays emitted from the microfocus X-ray generator.

That is, the focus adjustment of the microfocus X-ray generator, which requires the second X-ray detector to specifically confirm or adjust the size and position of the focal point, can be performed simultaneously in parallel and perpendicular directions to the slice plane. It can be done in real time. Therefore, the time required for this adjustment is only about several tens of seconds, so the time required is l
/100 <You can save money on leprosy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an X-ray tomography 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 tomography apparatus according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Micro focus X-ray generator, 2... Sample stage, 3... Inspection object, 4.6... Collimator, 5
...Multi-channel X-ray detector, 7...X-ray imaging section, 8
... X-ray generator moving stand, 9... High voltage generator, 10... X-ray control device, 11... Data collection device, 12... Computer, 13... CRT, 14. ...Mechanism control device, 15...System control device, 16...
Focus confirmation jig, 17...display device.

Claims (1)

[Claims] A microfocus X-ray generator that generates X-rays, a sample stage on which an object to be inspected whose internal state is to be inspected by the X-rays is installed, and arranged between the microfocus X-ray generator and the sample stage. and a collimator that converts the X-rays emitted from the microfocus X-ray generator into a parallel beam and irradiates the object to be inspected installed on the sample stage, and detects the amount of X-rays that have passed through the object to be inspected. a first X-ray detector; a second X-ray detector for confirming the size and position of the focal point of the X-rays emitted from the microfocus X-ray generator; and 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 the microfocus X-ray generator and the first X-ray detector, An X-ray tomography apparatus comprising: a moving mechanism that relatively moves the X-ray detector and the second X-ray detector.