JPS62299241A - X-ray beam converging apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention is intended for realizing, for example, an XPS (X-ray photoelectron spectroscopy) device or a fluorescent X-ray analyzer for microscopic analysis. The present invention relates to an X-ray beam focusing device for an X-ray source that irradiates a minute part of a sample.

(Prior art) For example, the sample size is on the order of 1 mm, 100 μm, or 10 μm.
It is not easy to create an X-ray source with high output that can selectively irradiate and excite tiny parts of the order of magnitude.

In order to increase the output, it is not advantageous to use a slit or aperture to cut the X-rays into tiny diameter ones.
In addition, charged particles can be focused using an electromagnetic field, and light (
While ultraviolet, visible, and infrared light can be narrowed down using optical lenses and mirrors, X-rays cannot be narrowed down in the same way.

Several attempts have been made to convert X-rays into beams with minute diameters. In the X-ray beam focusing device shown in FIG.
The incident X-rays 4 are converted into a minute diameter X-ray beam 8 using a total reflection cylindrical surface or a total reflection spherical surface 6.

In the X-ray beam focusing device shown in FIG. 6, incident X-rays 4 from an X-ray source 2 are converted into an X-ray beam 8 with a minute diameter using a diffraction spherical surface 10.

In the X-ray beam focusing device shown in FIG. Problem) The X-ray beam focusing device shown in Figures 5 to 7 attempts to focus X-rays into a minute diameter by diffraction or reflection using a spectroscopic crystal or zone plate.
There are problems such as the equipment becomes large, there are problems in obtaining sufficient X-ray intensity, and the diameter of the focused X41 beam is not small enough.

An object of the present invention is to realize another type of X-ray beam convergence device that can selectively irradiate or excite a minute part, for example, about several tens of micrometers or less.

(Means for Solving the Problems) The xg beam converging device of the present invention arranges a large number of micro-diameter pipes so that one collecting surface is large and the other collecting surface is small, and the other collecting surface is The central extension lines of each pipe are bundled to form a truncated cone so that they converge to one point, the one collecting surface is the X-ray incident surface, and the other collecting surface is the X-ray incident surface.
This is a line exit surface.

(Embodiment) FIG. 1 shows one embodiment, and FIG. 2 shows one micro-diameter pipe 14 used in the same embodiment.

As shown in FIG. 2, the pipe 14 used in this embodiment has a large inner diameter 14a at one end and a larger inner diameter 14b at the other end.
This is a pipe whose inner wall surface is sloped so that the

In this embodiment, the pipes 14 are bundled with the small diameter sides aligned and the large diameter sides aligned, so that the whole has a truncated conical shape, and each pipe 14 is bundled with the small diameter sides aligned and the large diameter sides aligned, and the pipes 14 are bundled together so that the whole has a truncated conical shape. The extension lines of the central axis intersect at one point A. The collecting surface 16 in which the large diameters are bundled together is used as an entrance surface for the incident X-rays 20, and the collecting surface 18 in which the small diameters are bundled together is used as an exit surface for the X-rays.

Regarding one pipe 14, when X-rays 20 are incident from the side 14a with a larger inner diameter as shown in FIG.
At this time, it is assumed that the inclination angle of the inner wall of the pipe 14 satisfies the total reflection condition for the incident X-ray 20. Depending on the relationship between the diameter and length of the pipe 14, the incident X-rays 20 travel toward the exit 14) 1 while undergoing repeated total reflection. The incidence X is approximately equal to the size of the entrance side 14a with a large inner diameter.
i! The beam diameter of X-rays 20 becomes smaller than the beam diameter of the incident X-rays 20 when exiting from the exit 14b.

In the embodiment shown in FIG. 1, the pipes 14 are aligned and the extension lines of their central axes intersect at one point on the exit side, so a much larger amount of X-rays is emitted than if there was only one pipe 14. , the X-ray beam becomes small and is not much different from the case where there is only one pipe 14. In other words, it becomes a narrow X-ray beam 22 with large power (high luminous flux density of X-rays).

As the material of the pipe 14, fused quartz or metal can be used. In either case, the inner wall surface of the pipe 14 must have a nearly mirror-like surface.

In the embodiment shown in Fig. 1, the pipes to be bundled into a truncated cone shape are not limited to those whose inner diameters are different at the inlet and outlet sides as shown in Fig. Cylindrical pipes 24 having the same inner diameter may also be used. In this case, if the pipes 24 are bundled into a truncated cone shape, the X-ray
Pipe 24 on the collecting surface on the larger side, which is the incident surface of 0.
Since gaps are formed between them, these gaps may be filled with a suitable filler.

FIG. 4 shows a partial sectional view of another embodiment.

In the case of the embodiment shown in FIG. 1, the condition for total reflection may no longer be satisfied for the incident X-rays 20 in the pipes 14 that are far from the center of the pipe assembly. Therefore, in this embodiment,
) [Which pipe 26-1.26-2.
......, the shape of the central pipe and the peripheral pipe are different so that the X-ray incident side is almost parallel to the incident X-ray, and the extension of the central axis on the exit side intersects at one point A. It is a collective body. This results in a more efficient X-ray beam focusing device.

Here, the conditions for total reflection of X-rays can be expressed as in the following equation. The critical angle ΦC for the reflecting mirror is
It is expressed as Φc=(2δ)1/8.

δ=2,02(m/z)ρλ"XIO', where 2 is the atomic number, m is the atomic weight, ρ is the density, and λ is the wavelength (input) of the X-ray.The material is fused silica, and the X-ray is AQK
When α (8,339 people), the critical angle ΦC is approximately 1. lo
(Japanese Journal of Applied Physics)
f Applied Physics) Volume 21, No. 9
No. 1, pp. 1347-1358).

When a pipe is made of fused silica or the like, it is possible to reduce the inner diameter to about 10 μm or several tens of μm. If the length of the pipe is made to be, for example, 100 times or more than its inner diameter, the critical angle for total reflection of X-rays will be approximately 1.
Since the angle is approximately 10 degrees, the X-ray beam can be focused to a point almost close to the inner diameter of the pipe.

In the case of the present invention, the light source of the incident X-rays may be a point light source or a parallel X-ray source.

(Effects of the Invention) According to the present invention, a much smaller X-ray beam can be obtained with higher power than the conventional X-ray beam focusing device. With this, the long-awaited XPS of minute parts (
This makes it possible to perform ESCA) analysis, and also to perform fluorescent X-ray analysis of minute parts.

[Brief explanation of drawings]

Fig. 1 is a side view showing one embodiment of the present invention, Fig. 2 is a sectional view showing one pipe used in the same embodiment, and Fig. 3 is a side view showing one pipe used in the same embodiment. FIG. 4 is a partial sectional view showing another embodiment, and FIGS. 5 to 7 are schematic perspective views showing essential parts of a conventional X-ray beam focusing device. 14.24... Pipe, 16... X-ray entrance surface, 18... X-ray exit surface, 20... Incident X-ray. 22... Outgoing X-rays, A... Convergence point of the X-rays.

Claims (1)

[Claims] (1) A large number of small-diameter pipes are bundled so that one collecting surface is large and the other collecting surface is small, and the central extension of each pipe from the other collecting surface converges to one point. An X-ray beam convergence device having a truncated cone shape, wherein the one collecting surface is an X-ray entrance surface, and the other collecting surface is an X-ray exit surface.