JPH0434400A - Soft x-rays multilayer film reflecting mirror - Google Patents

Abstract

PURPOSE:To obtain a soft X-rays multilayer film reflecting mirror, which is superior in endurance to a Li group/Ni multilayer film reflecting mirror and obtains a higher reflection factor than the multilayer film reflecting mirror of Be/Ni and SiO2/Ni. CONSTITUTION:LiF(lithium fluoride) is used as a material exhibiting higher refractive index among two materials forming a multilayer film, and since Ni(nickel) is used as a material exhibiting low refractive index, the refractive index of a LiF/Ni multilayer film composed of LiF and Ni is higher than those of the conventional SiO2/Ni multilayer film and Be/Ni multilayer film to soft X-rays of a wave length range of 23Angstrom -44Angstrom . In addition, since LiF is inactive and does not chemically react with moisture in the air, the film composed of LiF is chemically stable.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a soft X-ray multi-NWj1 reflector used in biological X-ray microscopes, etc. The present invention relates to a soft X-ray multilayer reflector that exhibits high reflectivity for soft X-rays in the human wavelength range.

(Prior art) An X-ray neck mirror for observing proteins in a living body uses the difference between the absorption rate of hydro-power X-rays and the absorption rate of proteins for X-rays to obtain shading of the image23. Soft X-rays in the wavelength range of human to 44 people are used. Soft X-ray 23 people ~ 4
As shown in FIG. 3, the absorption rate of protein for soft X-rays in the wavelength range of four people is different from the absorption rate of water for soft X-rays.

As is clear from this figure, the absorption rate of proteins such as polyimide and protein for soft X-rays is about 10 times the absorption rate of water for soft X-rays.

However, all substances are soft X in the wavelength range of 23 to 44 people.
Since it has a refractive index close to 1 for soft X-rays, a reflecting mirror that exhibits a high reflectance for soft X-rays cannot be constructed of a single material. Therefore, in order to obtain a relatively high reflectance for soft X-rays, a multilayer reflector has been proposed that has a multilayer film in which two materials exhibiting mutually different refractive indexes for X-rays are laminated alternately. ing. The thickness of the high refractive index layer made of a substance exhibiting a high refractive index among the above substances and the thickness of the low refractive index layer consisting of a substance exhibiting a low refractive index in the multilayer film of the multilayer reflector are the same as the high refractive index layer. Since the X@ reflected at the boundary with the low refractive index layer is set to a value that strengthens each other, the phases of the XwA reflected at the boundary between the high refractive index sFw and the low refractive index layer match each other. Therefore, a relatively high reflectance can be obtained.

The reflectivity of a multilayer mirror for X-rays is determined by the combination of a material with a high refractive index and a material with a low refractive index that form the multilayer film, and is a combination of materials that can obtain an extremely high reflectance. Several have been proposed.

One of the combinations of materials is to use Be as a material that exhibits a high refractive index with respect to X-rays and Ni as a material that exhibits a low refractive index with respect to X-rays, and a Be/Ni multilayer film using this combination is used. Reflectors are widely used.

Another material combination is 5i02, which has a high refractive index, and Ni, which has a low refractive index, and there is a SiO2/Ni multilayer WA reflector obtained by this combination (Japanese Patent Application No. 125024/1982). .

Furthermore, as a combination of other materials, Li exhibiting a high refractive index
, LiH or Li2O, and Ni which exhibits a low refractive index, and the Li-based/
There is a Ni multilayer film reflector (Patent application No. 63-192158)
issue).

(Problems to be Solved by the Invention) Among the multilayer reflectors made of a combination of the various materials mentioned above, the Li-based/Ni multilayer reflector has a B e /N has a higher reflectance than that of the multilayer reflector and the SiO,/Ni multilayer reflector.However, since Li-based substances such as Li, LiH, and LizO are rich in activity, Li-based substances The Li-based substance is easily converted into other substances due to chemical changes such as absorption of moisture in the air, and the reflective performance of the Li-based/Ni multilayer reflector deteriorates over time. As a result, the durability of the Li-based/Ni multilayer reflector is inferior to that of other multilayer reflectors.

The purpose of the present invention is to provide a reflector that is superior in durability to a Li-based/Ni multilayer film reflector, and that is also made of Be/Ni and SiO,
An object of the present invention is to provide a soft X-ray multilayer film reflector that can obtain a higher reflectance than a /Ni multilayer film reflector.

(Means for Solving the Problems) The present invention has a multilayer film in which two substances exhibiting mutually different refractive indexes with respect to X-rays are laminated alternately. The thickness of the high refractive index layer made of a substance with a low refractive index and the thickness of a low refractive index layer made of a substance with a low refractive index are such that X-rays reflected at the boundary between the high refractive index layer and the low refractive index layer mutually strengthen each other. The soft X-ray multilayer film reflecting mirror is set to a value that matches the above, and is characterized in that the material of the high refractive index layer is LiF, and the material of the low refractive index layer is Ni.

(Function) Of the two substances that form the multilayer film, LiF (sulfur oxide) is used as the substance that exhibits a high refractive index, and Ni (nickel) is used as the substance that exhibits a low refractive index. L i F / consisting of a combination of and Ni
The Ni multilayer film is superior to the conventional SiO□/Ni multilayer film and Be/N for soft X-rays in the 23-44 wavelength range.
It shows a reflectance higher than that of the i multilayer film, and L
Since fF is inert, L jF does not chemically react with moisture in the air, so a film made of LiF is chemically stable.

(Example) Fig. 1 is a sectional view showing an embodiment of the soft X-ray multilayer film reflector of the present invention, and Fig. 2 is a sectional view showing the soft X-ray multilayer film reflector of Fig. 1 and the conventional X-ray multilayer film reflector. FIG. 3 is a diagram showing the relationship between reflectance of a mirror and wavelength.

The soft X-ray multilayer film reflecting mirror 10 has a substrate 12 and a multilayer film 14 disposed on the substrate 12, as shown in FIG. The multilayer M14 includes an N1 layer 16 made of Ni and a LiF
Eight LiF layers are alternately stacked on one layer. Nt
The multilayer film 14 is formed by puttering 8 putters on one layer of l'l16 and one LiF layer, and the number of laminated layers of the multilayer film 14 is 99.

The LiP layer 18 exhibits a refractive index higher than that of the N1 layer 16 for soft X-rays with a wavelength stop of 23.3 to 44, and
The difference between the refractive index of the first iF layer 8 and the refractive index of the N1 layer 16 is small, and the slight difference in refractive index between the LiFjl 18 and the N1 layer 16 causes soft It is slightly reflected at each boundary between the tLiF layer 18 and the N1 layer 16. N1 layer 16 and LiF
The thickness of layer 1 and upper layer 8 is set to such a value that the phases of the soft X-rays reflected at the boundaries of each layer are aligned and the reflected waves strengthen each other. Note that the dimension in the thickness direction of the N1 layer 16 and the dimension in the lateral direction of the first LiF layer shown in FIG. 1 are larger than the dimension in the lateral direction.

Next, when the X-rays are incident on the multilayer film 14 at an angle of 20°,
As shown in FIG. 2, the soft X-ray multilayer reflector 10 has 23
．． In the wavelength range of 3 to 80 people, the conventional B e /
It exhibits a higher reflectance than the Ni multilayer reflector and the SiO2/Ni multilayer reflector. The X-ray reflectance of each multilayer film reflector shown in this figure is a value obtained by numerical calculation, and is based on the reflectance of the conventional Be/Ni multilayer film reflector and the 5iOz/Ni multi-Fi! It is calculated assuming that the reflectivity of the mirror is 6 and the number of layers is 99.

Since LiF is an inert substance, LiF does not chemically react with moisture in the air, so the LLFM made of LtF 18 is a chemically stable layer. As a result, a polygonal layer consisting of 8 i Fi 16 on one LjF layer is formed.
! ! The durability of the soft X-ray multilayer film reflector 10 having A14 is superior to that of the conventional Li-based/N multilayer film reflector.

(Effects of the Invention) According to the present invention, since the high refractive index layer of the multilayer film is made of LiF and the low refractive index layer is made of Ni, the reflectance for soft X-rays in the wavelength range of 23 to 44 is low. Conventional B
The reflectance can be made higher than that of e/Ni multilayer reflector and SiO□/Ni multilayer reflector, and the durability is improved compared to that of conventional Li-based/N1 multilayer reflector. be able to.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the soft X-ray multilayer film reflector of the present invention, and FIG. 2 is a reflectance of the soft X-ray multilayer film reflector of FIG. 1 and the conventional X-ray multilayer film reflector. FIG. 3 is a diagram showing the relationship between wavelength and the absorption rate of various substances for X-rays of about 30 people. 10... Soft X-ray multilayer reflector, 14... Many! a membrane,
16...Ni layer (low refractive index layer), 18...LiF layer (high refractive index N). Figure 1

Claims (1)

[Claims] It has a multilayer film in which two substances exhibiting mutually different refractive indexes with respect to X-rays are laminated alternately, and the thickness and low refraction of the high refractive index layer made of the substance exhibiting the higher refractive index of the two substances. The thickness of the low refractive index layer made of a material that exhibits a soft A soft X-ray multilayer film reflecting mirror, characterized in that the material of the high refractive index layer is LiF, and the material of the low refractive index layer is Ni.