JPH06300663A - Total scattering measuring equipment for x-ray region - Google Patents

Abstract

PURPOSE:To allow evaluation of roughness of mirror face in X-ray region. CONSTITUTION:A layer 12 for scattering visible light is formed on the inner face of an integrating sphere 11 filled with a fluorescent material 25 for absorbing X-rays to emit visible light. X-rays 32 from an X-ray source 31 passes through an incident hole 17 and an incident spatial path 26 to impinge on a test mirror 14 which reflects the X-rays 33 through an outlet spatial path 27 and an outlet hole 19 to the outside. X-rays 34 scattered on the test mirror 14 impinges on the fluorescent material 25 and converted into visible light 35 which repeats scattering in the scattering layer 12 within the integrating sphere 11 and arrives at an optical detector 22. The quantity of light detected by the optical detector 22 corresponds to total scattering quantity of the test mirror 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray region total scattering measuring device used for evaluating the roughness of a mirror surface and measuring the total amount of scattering with respect to X-rays.

[0002]

2. Description of the Related Art Conventionally, in order to evaluate the roughness of a mirror surface, visible light is incident on the mirror surface and the total amount of scattered light generated at that time is measured. This visible light region total scattering measuring device had the structure shown in FIG. A scattering layer 12 is formed on the inner surface of the integrating sphere 11. A test mirror mounting hole 13 is formed in a part of the integrating sphere 11, and a test mirror 14 whose mirror surface roughness is to be measured is mounted so as to close the test mirror mounting hole 13. The mirror surface 14a of the test mirror 14 to be measured is the inner surface side of the integrating sphere 11, and the integrating sphere 11 is placed on this mirror surface 14a.
Visible light 16 from a light source 15 outside An entrance hole 17 is formed in the integrating sphere 11 to pass the visible light 16. The emitting hole 19 is provided for emitting the reflected light 18 of the visible light 16 that has entered the mirror surface 14a to the outside.
1 is formed. A photodetector 22 for receiving the scattered light 21 generated on the mirror surface 14a is attached to the integrating sphere 11 with its detection surface inserted.

In other words, if the mirror surface 14a has irregularities or deposits and is an imperfect mirror surface, scattered light 21 that is directed in a direction other than the reflected light 18 is generated. This scattered light 21 is reflected light 18
It is possible to evaluate the degree of unevenness of the mirror surface 14a, that is, the roughness, etc., by measuring the amount of this scattered light that occurs in the entire circumferential direction other than the above direction. The scattered light 21 does not go out in a fixed direction like the reflected light 18 but goes out in the entire circumferential direction, so that the integrating sphere 11 is used to efficiently collect it. There is a scattering layer 12 on the inner wall of the integrating sphere 11, and the ideal scattering layer is 100% of the incident light in all directions.
% Scatter. The light 21 scattered by the mirror surface 14a is scattered in the integrating sphere 11 and further scattered, and the light 21 scattered many times reaches the photodetector 22 and is detected as an electric signal. The light emitted in the entire circumferential direction repeats scattering inside the integrating sphere 11 and eventually reaches the photodetector 22.

If the amount of light from the light source 11 is constant with time and the scattering on the test mirror surface 14a does not change with time, the time-saturated value of the amount of light detected by the photodetector 22 is measured on the test mirror surface 14a. Is equal to the total scattered light amount of. Realistic integrating sphere 11
In the above, innumerable white fine particles having a diameter of several tens of μm are adhered to the inner wall as the scattering layer 12. As the fine particles, barium sulfate, fine particles of an organic polymer, or the like is used, and the scattering efficiency is 90% or more. If the scattering efficiency is not 100%, a part of the light 21 scattered by the mirror surface 14a will be part of the photodetector 22.
However, with such a high efficiency of 90% or more, the amount of light detected by the photodetector 22 is obtained by multiplying the scattered light on the mirror surface 14a by the scattering efficiency of the scattering layer 12 of the integrating sphere 11. Almost equal. Further, the entrance hole 17, the exit hole 19, the test mirror mounting hole 14, etc. are made as small as possible in order to reduce the efficiency of the integrating sphere 11.

[0005]

In the past, the measurement of the total amount of scattering from the mirror surface 14a was mainly limited to light in the wavelength range of visible light. In recent years, a mirror surface for light in a shorter wavelength region has been made, and particularly, a mirror surface for light in an X-ray region has been developed. As is well known, X-rays have little reflection on the material surface and are very sensitive to surface irregularities.
In order to develop a reflector for rays, it is important to measure the total amount of scattering on the mirror surface and evaluate the mirror surface. However, it could not be measured because there was no integrating sphere that can be used in the X-ray region. This is because most of the light in the X-ray region is transmitted and absorbed in the substance and the scattering efficiency on the surface is extremely low (0.1% or less), so that the scattering layer cannot be formed on the inner wall of the integrating sphere.

[0006]

According to the present invention, a fluorescent substance body that absorbs X-rays and emits visible light is filled in the integrating sphere, and a test mirror is attached to the integrating sphere as in the conventional case. In addition, an entrance hole and an exit hole are formed respectively, and a scattering layer is formed on the inner surface. Further, the fluorescent substance body is formed with an incident space path through which incident light passes from the entrance hole to the test mirror and an exit space path through which reflected light passes from the test mirror to the exit hole. X-rays from an X-ray source provided outside the integrating sphere can be made incident on the test mirror through the entrance hole. The visible light emitted from the fluorescent material is repeatedly scattered in the integrating sphere and finally received by the photodetector.

[0007]

When X-rays are incident on the mirror surface of the test mirror, the reflected light (X-rays) is emitted from the emission port to the outside, and the scattered X-rays generated on the mirror surface are incident on the phosphor body. Visible light is emitted from the fluorescent substance body, and this visible light repeatedly scatters in the integrating sphere in the scattering layer and reaches the photodetector. The amount of light reaching this photodetector corresponds to the total amount of X-ray scattering by the test mirror.

[0008]

FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. 2 are designated by the same reference numerals. In the present invention, the phosphor body 2 that absorbs X-rays and emits visible light in the integrating sphere 11
5 is filled. The phosphor material 25 has an entrance hole 17
The path through which the incident light from reaches the test mirror 14 is defined as a space,
That is, the incident space passage 26 is formed, and the passage through which the reflected light from the test mirror 14 reaches the emission hole 19 is a space, that is, the emission space passage 27 is formed. The portion of the test mirror 14 facing the mirror surface 14a is also made small by removing the fluorescent substance body 25 slightly. Further, in this example, the scattering layer 12 is also formed over the entire inner surfaces of the incident space path 26, the emission space path 27, and the small space 28. An X-ray source 31 is provided outside the integrating sphere 11 in place of the light source 15, and X-rays 32 from the X-ray source 31 can be made incident on the test mirror 14 through the incident hole 17. As the material of the fluorescent substance body 25, any substance that converts X-rays into visible light may be used, and a substance obtained by mixing thallium with sodium iodide, a compound of an oxide of bismuth, germanium, or the like is used.

According to this structure, the X-ray 32 is incident on the mirror surface 14a of the test mirror 14 through the incident space path 26, and the reflected light (X-ray) 33 is emitted to the outside through the emission space path 27. The X-rays (scattered light) 34 scattered by the mirror surface 14a enter the fluorescent substance body 25, the X-rays are absorbed in the fluorescent substance body 25, and the visible light (fluorescent light) 35 is emitted. The visible light 35 converted from the X-rays reaches the photodetector 22 while being repeatedly scattered on each wall surface, that is, the scattering layer 12.

The dose from the X-ray source 31 is constant over time,
If the scattering at the test mirror 14 does not change with time, in addition to the scattering efficiency of the scattering layer 12, the conversion efficiency of X-rays into visible light,
Considering the transmission efficiency of X-rays in the fluorescent substance body 25, the total scattered X-ray dose on the mirror surface 14a of the test mirror 14 can be calculated from the amount of light detected by the photodetector 22 as in the case of using conventional visible light. Can be measured.

The incident space path 26 and the exit space path 2
7 and the scattering layer 12 on each inner surface of the small space 28 may be omitted.

[0012]

As described above, according to the present invention, X
A ray is incident on the mirror surface to be evaluated, the scattered X-rays are converted into visible light, and the amount of visible light is measured to evaluate the degree of unevenness that is smaller than visible light, that is, the degree of a fine rough surface. You can

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional total scattering measuring device using visible light.

Claims (1)

[Claims] 1. A test mirror mounting hole in which a test mirror whose surface roughness is to be evaluated is mounted and closed, and a photodetector hole.
An integrating sphere having an entrance hole and an exit hole, a fluorescent substance body that fills the integrating sphere and emits visible light by absorbing X-rays, and in the fluorescent substance body, the entrance hole and the test mirror. And a space for incidence and a space for emission formed respectively between the emission hole and the test mirror, and between the integrating sphere and the fluorescent substance body, and scattering for scattering the visible light. A layer, an X-ray source that is provided outside the integrating sphere, and that makes X-rays enter the test mirror through the incident space path from the incident hole, and one end so as to close the photodetector hole. An X-ray region total scattering measurement apparatus comprising: a photodetector, which is attached to the photodetector, and which detects the amount of visible light.