JPH1164595A - X-ray spectral element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate an X-ray converged with sufficient intensity and little background by converging the X-ray emitted vertically to z-direction from one focus of two focuses on an elliptic columnar surface to the other focus. SOLUTION: In an X-ray spectral element 1 having a multilayer film 3 accumulated on a base 2, a part of the focus F1 , F2 side of an elliptic cylindrical surface E1 extending in paper surface vertical direction represented by x<2> /a<2> +y<2> /b<2> =1 in respect to orthogonal coordinate xyz (z-axis passes the origin O and extends on this side vertical to the paper surface) is taken as a diffracting surface 1a. The periodic length d0 of the multilayer film 3 is set so that X-rays 4A, 4b having a wavelength to be diffracted which are emitted vertically to z-direction from one focus F1 of the two linear focuses F1 , F2 extended in z-direction of the elliptic cylindrical surface E1 is diffracted in an optional point on the diffracting surface 1a by the diffracting surface 1a and converged to the other focus F2 vertically to z-direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray spectroscopy element capable of generating convergent X-rays with sufficient intensity and low background.

[0002]

2. Description of the Related Art Conventionally, for example, so-called total reflection fluorescent X
In the X-ray analysis, as shown in FIG. 2, X-rays spread and emitted from a linear X-ray source (a linear focus on a target of an X-ray tube and extending perpendicular to the paper) 20 are diverged. The light is radiated to the spectroscopic element 23 by narrowing the divergence angle ψ using the slit 22, and the spectroscopic element 23 separates the light into monochromatic light.
Sample 2 fixed to a sample table 25 using the line 24 as a primary X-ray
The fluorescent X-rays 28 generated from the sample 26 are incident on the detector 29 while escaping to the right side in the drawing so that the totally reflected X-rays 27 are not incident on the detector 28. And analyze it. Here, in order to cause total reflection, the incident angle α is usually set to a small angle of, for example, about 0.05 to 0.1 degrees. Therefore, the X-rays that are spread and emitted from the linear X-ray source 20 are converted into small divergence angles ０．０５ of about 0.05 degrees by using the divergence slits 22.
Need to be squeezed.

[0003]

Therefore, the X-ray source 2
Since only a small part 21 of the X-rays emitted from 0 is used, the intensity of the primary X-rays 24 applied to the sample surface 26a is
Sometimes accurate analysis is not enough. When the spectroscopic element 23 is of a log spiral type or a Johan type, the optical system does not focus on at least one of the X-ray source 20 side and the sample 26 side, and aberration occurs.
At line 24, the background cannot be reduced sufficiently and, again, the analysis cannot be sufficiently accurate.

[0004] The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an X-ray spectroscopy element capable of generating X-rays having sufficient intensity and a small background and converging (focusing).

[0005]

In order to achieve the above object, an X-ray spectroscopic element according to claim 1 is an X-ray spectroscopic element having a multilayer film deposited on a substrate. A part on the focal side of the elliptical cylinder surface represented by ² / a ² + y ² / b ² = 1 is defined as a diffraction surface. The periodic length of the multilayer film is, at an arbitrary point on the diffraction surface, the wavelength to be diffracted perpendicularly to the z direction from one of two linear focal points extending in the z direction of the elliptic cylinder surface. X-rays are set to be diffracted on a diffraction surface and condensed at the other focal point in a direction perpendicular to the z direction.

According to the X-ray spectroscopy device of the present invention, the X-rays are emitted from a linear X-ray source placed at one focal point and received, for example, an X-ray having a divergence angle of about 0.1 degree, and are diffracted. However, since the light can be condensed linearly at the other focal point with a convergence angle of about 0.05 degree, the intensity is sufficient, the background is small, and X
Lines can be generated.

According to a second aspect of the present invention, there is provided an X-ray spectroscopic element in which a multilayer film is deposited on a substrate. First, regarding the orthogonal coordinates xyz, x ² / a ² + y ² / b ² + z ² / b ²
A part on the focal side of the spheroidal surface represented by = 1 is defined as a diffraction surface. Then, at an arbitrary point on the diffraction plane, the X-ray having a wavelength to be diffracted from one of the two focal points of the spheroid is diffracted by the diffraction plane. Is set so that light is condensed at the other focal point.

According to the X-ray spectroscopy element of the present invention, the light is emitted from a point-like X-ray source placed at one focal point, and received, for example, an X-ray having a divergence angle of about 0.1 degree, and diffracted. However, since the light can be condensed at the other focal point in a point-like manner at a convergence angle of about 0.05 degree, the intensity is sufficient and the background is small and X
Lines can be generated.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an X-ray spectroscopy device according to a first embodiment of the present invention will be described. As shown in FIG.
Ray monochromator 1 is the X-ray monochromator 1 deposited multilayer film 3 on the substrate 2, first, the rectangular coordinates xyz (z-axis passes the origin O, the front-facing perpendicular to the paper surface), x ² /
a part of ^{a 2 + y 2 / b 2} = focal F ₁ of the ellipsoidal cylinder plane E ₁ extending in the direction perpendicular to the plane represented by 1, F ₂ side is the diffractive surface 1a. Then, at any point on the diffraction surface 1a, the periodic length d ₀ of the multilayer film 3 is _one of the two linear focal points F ₁ and F ₂ extending in the z direction of the elliptic cylindrical surface E _1. To z
Perpendicular to the direction (along the plane perpendicular to the z-axis, for example along the plane of the paper)
The emitted X-rays 4A and 4B having a wavelength to be diffracted are diffracted by the diffraction surface 1
and diffracted by a, perpendicular to the z-direction at the other focal point F ₂ (along a plane perpendicular to the z-axis) is set so as to condense. Such an artificial multilayer film 3 can be formed, for example, by alternately depositing a tungsten layer and a silicon layer, and the sum of the thicknesses of one set of the tungsten layer and the silicon layer is equal to the period length d _{0 of the} multilayer film 3. Becomes In FIG. 1, only three sets of layers of the multilayer film 3 are shown for ease of illustration.

That is, the multilayer film 3 has a wavelength λ emitted from a linear X-ray source placed at _one focal point F ₁ at an arbitrary point on the diffraction surface 1 a forming a part of the elliptic cylindrical surface E _1. X-rays 4 are received at an incident angle θ, and are diffracted and reflected at a reflection angle θ of the same angle. Here, the shape of the diffraction surface 1a, since the position of the focal point F ₁ is known, the incident angle (reflection angle) at each arbitrary point on the diffraction surface 1a theta geometrically unambiguously determined, The diffraction Wavelength λ of X-ray 4 to be
Is also known, the so-called d value characterizing the period length of the multilayer film 3 satisfies the Bragg condition of the following equation (1).

2d sin θ = nλ (n is a diffraction order and a positive integer) (1)

The sin θ in the expression (1) is derived from the expression of the elliptic cylinder surface indicating the shape of the diffraction surface 1a.
, And n = 1, the d value is expressed by the following equation (2) at an arbitrary point P (x ₁ , y ₁ , z ₁ ) on the diffraction surface.

[0013] ^{d = λ (a 2 + b} 2 -x 1 2 -y 1 2) 1/2 / 2b ... (2)

Since the d value can be controlled by changing conditions such as the deposition time and masking when forming the multilayer film 3 on the substrate 2, the X-ray spectroscopy device 1 of the first embodiment can be controlled as described above. The multilayer film 3 can be manufactured by finding and adjusting the conditions for forming the multilayer film 3 that cause a diffraction phenomenon of diffracting the X-ray 4 of wavelength λ emitted from the focal point F ₁ .

However, it is known that this d value does not exactly match the actual period length d ₀ of the multilayer film 3 due to the refraction phenomenon of X-rays, and has the relationship of the following equation (3). I have.

D = d ₀ [1− (2δ−δ ² ) / sin ² θ] ^1/2 (3)

That is, as described above, if the conditions for forming the multilayer film 3 are adjusted so as to cause a desired diffraction phenomenon, and the X-ray spectroscopy device 1 of the first embodiment is manufactured, The cycle length d ₀ satisfies Expression (3). In the expression (3), δ is a refractive index determined by the composition of the multilayer film 3 and the like.

According to the X-ray spectroscopy device 1 of the first embodiment,
As shown in FIG. 1, a linear X placed at _one focal point F1
An X-ray 4 emitted from the source and narrowed to, for example, a divergence angle の of about 0.1 ° is diffracted and condensed linearly at the other focal point F ₂ at a convergence angle γ of about 0.05 °. be able to. That is, for example, when irradiating a sample with X-rays having a convergence angle γ of about 0.05 degree, the angle at which the X-rays emitted from the X-ray source are reduced is as follows:
The angle may be, for example, about 0.1 degree instead of 0.05 degree, and X-rays emitted from the X-ray source can be used with, for example, about twice the efficiency of the related art. Therefore, it is possible to generate the X-rays 5 having sufficient intensity and converging with little background.

Next, an X-ray spectroscopy device according to a second embodiment of the present invention will be described. As shown in FIG.
1, in the X-ray monochromator 11 depositing a multilayer film 13 on the substrate 12, first, the rectangular coordinates xyz, x ^{2
/ A 2 + y 2 / b} 2 + z 2 / b 2 = 1 at the focal point F ₃ of the spheroid E ₂ represented, F ₄ side of the part and the diffractive surface 11a. That is, in the X-ray monochromator 11 of the second embodiment, an ellipse indicated by a two-dot chain line in FIG. 1, a part of spheroid E ₂ is rotated about the x-axis and the diffraction surface 11a, FIG. 1 is a sectional view. The period length d ₀ of the multilayer film 13, at any point on the diffraction surface 11a, and emitted from the focal point F ₃ of one of said spheroidal punctate bifocal F ₃ of E _2, F ₄ diffraction X-rays 14A and 14B of desired wavelength
Was converted, diffracted by the diffraction surface 11a, it is set so as to condense the other focal point F _4.

That is, the multilayer film 13 has a spheroidal surface E ₂
At an arbitrary point on the diffraction surface 11a forming part of the wavelength λ emitted from the point-like X-ray source placed at one focal point F _3.
X-rays 14 are received at an incident angle θ, and are diffracted and reflected at a reflection angle θ of the same angle. Here, diffraction surface 1
The shape of 1a, since the position of the focal point F ₃ is known, the angle of incidence at each arbitrary point on the diffraction surface 11a (reflection angle)
θ is uniquely determined geometrically, and the wavelength λ of the X-ray 14 to be diffracted is also known. Therefore, the so-called d value that characterizes the period length of the multilayer film 13 is determined by the X-ray spectroscopic element of the first embodiment. As in the case of 1, the Bragg condition of the above equation (1) is satisfied.

The sin θ in the equation (1) is derived from the spheroidal equation representing the shape of the diffraction surface 11a. If this is substituted into the equation (1) and n = 1, the d value is At an arbitrary point P (x ₁ , y ₁ , z ₁ ) on the surface, the following equation (4)
It is represented by

[0022] ^{d = λ (a 2 + b} 2 -x 1 2 -y 1 2 -z 1 2) 1/2 / 2b ... (4)

The X-ray spectroscopy element 11 of the second embodiment also finds and adjusts the conditions for forming the multilayer film 13 that causes the diffraction phenomenon of diffracting the X-ray 14 having the wavelength λ emitted from the focal point F _3. Can be manufactured. However,
Similarly to the X-ray spectroscopy element 1 of the first embodiment, the d value does not exactly match the actual period length d ₀ of the multilayer film 13 due to the refraction of X-rays. Have a relationship. That is, if the X-ray spectroscopy element 11 of the second embodiment is manufactured by adjusting the formation conditions of the multilayer film 13 so as to cause a desired diffraction phenomenon, the actual period length d ₀ of the multilayer film 13 is expressed by the following equation. (3) is satisfied.

According to the X-ray spectroscopy element 11 of the second embodiment, X-rays emitted from a point-like X-ray source placed at one focal point F ₃ and reduced to a divergence angle の of, for example, about 0.1 ° diffracted receiving line 14, the other focal point F ₄ can be condensed to a spot-like in γ converging angle of about 0.05 degrees. That is, for example, when irradiating the sample with X-rays having a divergence angle γ of about 0.05 degrees, the angle at which the X-rays emitted from the X-ray source are narrowed may be about 0.1 degrees instead of 0.05 degrees. X-rays emitted from the X-ray source can be used with, for example, about four times the efficiency of the conventional one. Therefore, it is possible to generate the X-rays 15 having sufficient intensity and converging with little background.

[0025]

As described above, according to the present invention, X having a sufficient intensity and a small background is converged.
Lines can be generated.

[Brief description of the drawings]

FIG. 1 is a front view or a sectional view showing an X-ray spectroscopy element according to a first or second embodiment of the present invention.

FIG. 2 is a perspective view showing a conventional total reflection X-ray fluorescence spectrometer.

[Explanation of symbols]

1,11 ... X-ray spectroscopy element, 1a, 11a ... Diffraction surface, 2,
12 ... substrate, 3,13 ... multilayer, 4, 14 ... X-ray wavelength to be diffracted emitted from one focal point, the cycle length of d ₀ ... multilayer, F _1, F ₂ ... linear focus, F ₃ , F ₄ : point-like focal point, E ₁ : elliptical cylindrical surface, E ₂ : spheroidal surface.

Claims (2)

[Claims] 1. An X-ray spectroscopy device having a multilayer film deposited on a substrate, wherein x ² / a ² + y ² / b ² = 1 for orthogonal coordinates xyz.
A part on the focal side of the elliptical cylinder surface represented by the following expression is a diffraction surface, and the periodic length of the multilayer film is, at an arbitrary point on the diffraction surface, of two linear focal points extending in the z direction of the elliptic cylinder surface. X-rays having a wavelength to be diffracted and emitted perpendicularly to the z direction from one focal point are diffracted by the diffractive surface, and are set so as to be condensed to the other focal point perpendicularly to the z direction. X-ray spectroscopy element. 2. An X-ray spectroscopy device having a multilayer film deposited on a substrate, wherein x ² / a ² + y ² / b ² + z
A part on the focal point side of the spheroid represented by ² / b ² = 1 is defined as a diffraction surface, and the periodic length of the multilayer film is a point-like bifocal of the spheroid at an arbitrary point on the diffraction surface. An X-ray spectroscopy element characterized in that X-rays having a wavelength to be diffracted and emitted from one of the focal points are diffracted on a diffraction surface and condensed on the other focal point.