Large-aperture ultra-low absorption type Kinform lens and design method thereof

Abstract

The invention discloses a large-aperture ultra-low absorption type Kinform lens and a design method of the large-aperture ultra-low absorption type Kinform lens. The large-aperture ultra-low absorption type Kinform lens is characterized in that the large-aperture ultra-low absorption type Kinform lens comprises a plurality of final teeth which are arranged side by side along an x axis and have the tooth length of h, and the final teeth are symmetrically distributed along a y axis; wherein the x-axis direction is the aperture direction, and the y-axis direction is the X-ray incidence direction; # imgabs0 # m > = 1 and is an integer, lambda is the wavelength of the X-ray, delta is the refraction coefficient of the X-ray in the material, and the designed tooth length h in the y direction is the length of the material causing the 2 [pi] m phase difference. According to the invention, the fineness limit of the processing technology can be fully utilized, and the total length of each tooth inside is greatly reduced, so that the absorption of X-rays is reduced; on the basis, according to the communication type scheme designed by the invention, the reinforcing cross beam can be introduced under the condition that the phase matching of the lens is not damaged, so that the stability of the lens structure is improved, and the processing technology difficulty is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of optical devices and relates to a large-aperture ultra-low absorption Kinoform lens and a design method thereof. Background Art

[0002] The surface shape of the traditional X-ray refractive focusing lens is a parabola, such as Figure 1 (a). The outermost length of the lens increases with the increase of the aperture. However, the absorption of X-rays in the medium is too large. In order to reduce the absorption of X-rays and increase the numerical aperture of the lens, the traditional solution is to remove part of the material that causes the phase difference of integer multiples of 2π along the direction of X-ray propagation, that is, to remove the length of integer multiples of λ / δ (where δ is the refractive index of X-rays in the medium, refractive index n=1-δ+iβ, β is the absorption coefficient) to form a series of tooth-like structures. The lens obtained in this way is called a long kinoform lens, such as Figure 1 (b), the closer to the outside of the lens, the smaller the width of the teeth. In order to reduce the length of the lens, the teeth of the lens are often arranged together to form a Figure 1 (c) shows the short kinoform structure. In actual use, in order to reduce the collapse of the toothed structure during processing, a crossbeam is generally added to the bottom of the lens to reinforce the lens structure, such as Figure 1 As shown in (d), for a traditional kinoform lens, adding a crossbeam structure at the bottom of the toothed structure does not change the phase matching of X-rays passing through the lens.

[0003] The traditional Kinoform lens structure greatly reduces absorption compared to a simple parabolic refractive lens. However, it is limited by the processing tooth width limit. If a larger aperture is to be achieved, it is necessary to increase the width of each row of lens teeth by combining multiple rows of kinoforms. The total length of the teeth of the entire kinoform lens group from the periphery to the inside remains unchanged, and the tooth density gradually decreases from the periphery to the inside. The internal teeth do not fully utilize the precision of the processing technology, resulting in a relatively large absorption of X-rays. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a large-aperture ultra-low absorption Kinoform lens and a design method thereof. The present invention can make full use of the precision limit of the processing technology, greatly reduce the total length of each internal tooth, and further greatly reduce the absorption of X-rays compared with the traditional Kinoform lens; on this basis, the interconnected solution designed by the present invention can introduce a reinforcing beam without destroying the phase matching of the lens, thereby improving the stability of the lens structure and reducing the difficulty of the processing technology.

[0005] The technical solution of the present invention is:

[0006] A large-aperture ultra-low absorption Kinoform lens, characterized in that it comprises a plurality of final teeth with a tooth length of h arranged side by side along the x-axis, and each of the final teeth is symmetrically distributed along the y-axis; wherein the x-axis direction is the aperture direction, and the y-axis direction is the X-ray incident direction; m≥1 and is an integer, λ is the wavelength of the X-ray, δ is the refractive index of the X-ray in the material, and the designed tooth length h in the y direction is the material length that causes a phase difference of 2πm.

[0007] A design method for a large-aperture ultra-low absorption Kinoform lens, comprising the following steps:

[0008] 1) Establishing a surface model of the large-aperture ultra-low absorption Kinoform lens according to the design focal length f of the large-aperture ultra-low absorption Kinoform lens Among them, the x direction is the aperture direction, the y direction is the X-ray incident direction, and the z direction is the thickness direction; the designed tooth length in the y direction is m ≥ 1 and is an integer, λ is the wavelength of X-rays, δ is the refractive index of X-rays in the material, and the minimum tooth width that can be processed in the x direction in actual processing is Δ;

[0009] 2) Based on the face model Calculate the horizontal coordinate whose height is an integer multiple of h Where i ≥ 0 and is an integer;

[0010] 3) For the lens structure of x>0:

[0011] Starting from the origin x0=0, find the first i -x0≥Δ coordinate point x i , we can conclude that i=N1 at this time, In the face The material overlapping the area 0≤y≤N1*h is removed to obtain the first retained tooth. x0 is the abscissa of the starting point of the first retained tooth. The abscissa of the end point of the first retained tooth and the width of the first retained tooth Length L1 = N1*h, length distribution

[0012] Continue to find the first one that makes The coordinate point x i , we can conclude that i=N2 at this time, In the face The material in the overlapping area with N1*h≤y≤N2*h is removed to obtain the second retained tooth. is the starting point abscissa of the second retained tooth, The abscissa of the end point of the second retained tooth and the width of the second retained tooth Length L2 = N2*h, length distribution

[0013] And so on, find the first The coordinate point x i , we can conclude that i=N j , In the face With N j-1 *h≤y≤N j *h The material of the overlapping area is removed to obtain the jth retained tooth; where, is the starting point abscissa of the jth retained tooth, is the abscissa of the end point of the jth retained tooth, and the width of the jth retained tooth Length L j =N j *h, length distribution

[0014] Cut in the above manner until the lens aperture reaches the required size;

[0015] 4) According to the axial symmetry and step 3), calculate the lens structure of the part x<0;

[0016] 5) According to the designed tooth length h, the retained teeth obtained in steps 3) and 4) are decomposed into a number of final teeth with a tooth length of h in the length direction; the final teeth obtained are arranged side by side along the x-axis to obtain a large-aperture ultra-low absorption Kinoform lens.

[0017] Further, in step 5), for the length L j =N j *h's jth retained tooth, decompose it into N in the length direction j final teeth, each final tooth has a length of h and a width of W j , the length distribution of each final tooth is

[0018]

[0019] A design method for a large-aperture ultra-low absorption Kinoform lens, comprising the following steps:

[0020] 1) Establishing a surface model of the large-aperture ultra-low absorption Kinoform lens according to the design focal length f of the large-aperture ultra-low absorption Kinoform lens Among them, the x direction is the aperture direction, the y direction is the X-ray incident direction, and the z direction is the thickness direction; the designed tooth length in the y direction is m ≥ 1 and is an integer, λ is the wavelength of X-rays, δ is the refractive index of X-rays in the material, the minimum tooth width that can be processed in the x direction in actual processing is Δ, and the length of the beam in the y direction is t;

[0021] 2) For the lens structure of x>0:

[0022] 21) Starting from the origin x0=0, according to Find the first n such that x n -x0≥Δ, we can conclude that n=N1 at this time, and then add x>X1 and N 1* t <y<N 1* The material in the overlapping area (t+h) is removed to obtain the first connected tooth, whose end point abscissa The starting point abscissa X0 = 0; the length distribution of the first connected tooth is 0≤x≤X1; According to the designed tooth length h, the first connected tooth is divided into N1 final teeth, and the length distribution of each final tooth is 0≤x≤X1;

[0023] 22) In the region x>X1, according to Find the horizontal coordinate

[0024]

[0025] If x-X1<Δ, directly go to 23) to continue cutting the connected teeth. At this time, the number of isolated teeth after the first connected tooth n1=0;

[0026] If x-X1≥Δ, perform isolated tooth cutting:

[0027] Will With N 1* (t+h) <y<N 1* The material in the overlapping area of ​​(t+h)+N1*h is removed to obtain the first isolated tooth. The abscissa of the end point of the first isolated tooth is The horizontal coordinate of the starting point is Overall length The area below the first isolated tooth has a crossbeam with a length of T1=N1*t connected to the first connected tooth, which is used to decompose the first isolated tooth into N1 final teeth with a designed tooth length of h, and each final tooth is assigned a crossbeam with a length of t in the y direction; the first isolated tooth and the crossbeam below it form a reserved tooth, and its length distribution is According to the designed tooth length h, the retained tooth is decomposed into N1 final teeth including the crossbeam. The length distribution of each final tooth including the crossbeam is:

[0028] Continue to the next isolated tooth cutting, according to Calculate the distance Δr between each two horizontal coordinates i =x i -x i-1 , i>1 and is an integer; if Δr i ≥Δ, then the horizontal coordinate of the ith isolated tooth after the first connected tooth is obtained Will With N 1* (t

[0029] +h)+N1*(i-1)*h <y<N 1* The material in the overlapping area of ​​(t+h)+i*N1*h is removed to obtain the i-th isolated tooth after the first connected tooth, and its starting point abscissa is The end point abscissa is The total length is The area below the ith isolated tooth has a beam connected to the first connected tooth with a length of T1=N1*t. When the ith isolated tooth is decomposed into N1 final teeth, each final tooth is assigned a beam with a length of t in the y direction. The ith isolated tooth and the beam below form a reserved tooth, and its length distribution is

[0030] According to the designed tooth length h, the retained tooth corresponding to the ith isolated tooth is divided into N1 final teeth, and the length distribution of each final tooth is i>1;

[0031] When the n1+1th isolated tooth is calculated, When , stop acquiring isolated teeth and execute step 23);

[0032] 23) Cutting of connected teeth

[0033] according to Find the first x m So that it and the end point coordinates of the n1th isolated tooth The difference is ≥Δ, at this time m=m2, N2=N1+m2, and the abscissa of the end point of the second connected tooth is obtained.

[0034] x>X2 and

[0035] N1*(h+t)+n1*N1*h+m2*t <y<N1*(h+t)+n1*N1*h+

[0036] The material in the overlapping area of ​​(N1+m2)*h+m2*t is removed to obtain the second connected tooth. Distribution of material length remaining in the area According to the designed tooth length h, y2 is decomposed into N1+m2 final teeth, including two types of final teeth:

[0037] The first type of final teeth: N1 final teeth with the same design tooth length h, below which there are N1 beams with a length of t in the y direction connected to the first connecting tooth. The length distribution of each final tooth in the N1 final teeth is

[0038] The second type of final teeth: m2 final teeth with the same design tooth length h, and m2 beams with a length of t in the y direction connected to the second connected tooth are used below them. The length distribution of each final tooth in the m2 final teeth is

[0039]

[0040] 24) Similarly, after the connected teeth are cut, isolated teeth are cut. When the tooth width of the isolated teeth does not meet the requirements, connected teeth are cut again until the required caliber is obtained.

[0041] Furthermore, the i-th connected tooth is divided into N i +m i The total length distribution of the final teeth is N i The length distribution of each final tooth in the final teeth of the beam combination connecting the first-type final teeth and the first connected teeth to the i-1th connected teeth below is

[0042] m i The length distribution of each final tooth in the final teeth of the second type final teeth combined with the beam connected to the i-th connected tooth is

[0043] The total length distribution of the jth isolated tooth following the i-th connected tooth is:

[0044] The length distribution of each final tooth obtained by dividing the jth isolated tooth is: i>0 and is an integer, j>0 and is an integer.

[0045] The advantages of the present invention are as follows:

[0046] The advantage of the present invention is that under the same processing conditions, compared with the traditional Kinoform lens, the absorption rate of the lens is greatly reduced, and the removed materials are all integer multiples of the 2π phase difference, meeting the phase matching conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a diagram of X-ray focusing lens and traditional kinoform lens types;

[0048] (a) Parabolic X-ray refracting lens, (b) long kinoform lens, (c) short kinoform lens, (d) short kinoform lens with a crossbeam added at the bottom.

[0049] Figure 2 Schematic diagram of the method for obtaining a new type of kinform lens without a beam.

[0050] Figure 3 for Figure 2 The new beamless kinform lens obtained by arranging its teeth together results in a structural diagram.

[0051] Figure 4 Schematic diagram of the final beamless new kinform lens structure.

[0052] Figure 5 Schematic diagram of the method for obtaining a new type of kinform lens with a connected beam.

[0053] Figure 6 This is a schematic diagram of the final connected new kinform lens structure with a crossbeam. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention but not to limit the scope of the present invention.

[0055] (1) Large aperture low absorption lens design (no beam)

[0056] The lens is a cylindrical structure. Assuming that the design focal length of the X-ray lens is f, the cross-sectional shape is (where x direction is the aperture direction, defined as the width direction, y direction is the X-ray incident direction, defined as the length direction, and z direction is the thickness direction), design tooth length (m≥1, and is an integer), the minimum tooth width that can be processed in actual processing (defined as the width of the tooth in the x direction) is Δ. Where λ is the wavelength of the X-ray, δ is the refractive index of the X-ray in the material. h is the designed tooth length (defined as the maximum length of the tooth in the y direction), which is also the material length that causes a phase difference of 2πm (m≥1, and is an integer).

[0057] First, according to the lens surface formula, the horizontal coordinate of the lens with an integer multiple of height h is (i≥0, and is an integer). Since the entire lens is symmetric about the y-axis, only the x>0 portion is analyzed (the x<0 portion is obtained by mirroring with the y-axis as the axis of symmetry).

[0058] Starting from the origin x0=0, find the first i -x0≥Δ coordinate point x i (i≥1), we can conclude that i=N1 at this time, In the face The material in the overlapping area of ​​0≤y≤N1*h is removed to obtain the first retained tooth. Where x0 is the horizontal coordinate of the starting point of the first retained tooth, is the abscissa of the end point of the first retained tooth. The width of the first retained tooth is Length L1 = N1*h, length distribution is:

[0059] Go ahead and find the first one that makes The coordinate point x i (i>N1), we can conclude that i=N2 at this time, In the face The material in the overlapping area of ​​N1*h≤y≤N2*h is removed to obtain the second retained tooth. is the starting point abscissa of the second retained tooth, is the abscissa of the end point of the second retained tooth. The width of the second retained tooth is Length L2 = N2*h, length distribution is:

[0060]

[0061] And so on, find the first The coordinate point x i (i>N j-1 ), we can conclude that i=N j , Then the face shape N j-1 *h≤y≤N j *h The material in the overlapping area is removed to obtain the jth retained tooth. is the starting point abscissa of the jth retained tooth, is the abscissa of the end point of the jth retained tooth. The width of the jth retained tooth is Length L j =N j *h, the length distribution is:

[0062]

[0063] Cut in the above manner until the lens aperture reaches the required size.

[0064] In order to reduce the total length of the lens, each retained tooth is moved to be parallel to the first retained tooth after cutting. According to the previous calculation, the length of each retained tooth is an integer multiple of h. According to the final design requirements, the length of each tooth needs to be unified to h, so according to the number of h contained in the length of the retained tooth, the retained tooth is decomposed into several final teeth in the length direction. For example, according to the previous calculation:

[0065] The length of the first retained tooth is L1 = N1*h, then it is decomposed into N1 final teeth in the length direction. The length of each final tooth is h, and the width is still W1. The length distribution is

[0066] The length of the second retained tooth is L2 = N2*h, which is then decomposed into N2 final teeth in the length direction. The length of each final tooth is h, and the width is still W2. The length distribution is

[0067] By analogy, the length of the jth retained tooth is L j =N j *h, then decompose it into N in the length direction j final teeth, each final tooth has a length of h and a width of W j , the length distribution of each final tooth is

[0068]

[0069] Until the required aperture size is obtained, the tooth width of each final tooth obtained in this way is not less than Δ, and the length of the material removed is an integer multiple of h, which causes a phase difference of an integer multiple of 2π, ensuring the phase matching and focusing performance of the lens.

[0070] The x<0 part and the x>0 part are symmetric about the y-axis.

[0071] example:

[0072] like Figure 2 to Figure 4 As shown, this is the case where N1=1, N2=2, N3=2, and N4=3, and the shaded portion is the removed material (wherein, h=35.05μm, λ=2.4796e-05μm, δ=7.07395e-7, Δ=20μm).

[0073] The retained teeth of the traditional lens start from the origin, and the teeth become narrower as they go outward. When they become narrower than the processing limit width Δ, they cannot continue. At this time, if the required aperture is to be achieved, the width of the single row of teeth needs to be increased through multiple groups of combinations; this is equivalent to combining N identical short kinoforms together, and the number of teeth in the middle part and the two side parts of the entire lens group is the same, both N, and the width of the center part teeth is greater than the width of the two side teeth. The present invention is designed around the processing limit width Δ from the beginning, the width of each tooth is close to Δ, and the final lens has fewer teeth in the middle part and more teeth on the two sides. Therefore, under the same aperture and focal length, the transmittance is significantly increased and the absorption is reduced.

[0074] (ii) Large-aperture low-absorption connected lens design (with crossbeam)

[0075] Considering the processing factors, the teeth of the lens are not connected. When manufacturing, it is necessary to add beams to each row of teeth for reinforcement to prevent the tooth structure from collapsing. However, if a beam structure with a fixed width is directly added to the root of each tooth, the number of central and outer teeth is different, and the number of added beams is also different, which will destroy the phase matching of the lens. On this basis, a new design of a connected phase matching lens is proposed below. Assuming that the required beam length in the y direction is t, the length of each retained tooth is (m≥1, the length of the tooth retained here does not include the length of the beam t, and is the maximum length of the tooth in the y direction), the minimum tooth width that can be processed in actual processing is Δ. Assume that the design focal length of the X-ray lens is f, and its surface shape is Among them, the x direction is the aperture direction, which is defined as the width direction, the y direction is the X-ray incident direction, which is the length direction mentioned in this article, and the z direction is the thickness direction. The following operation is only performed on the x>0 part, and the x<0 part is symmetric with the x>0 part about the y axis. Here, the teeth that meet the conditions and are retained during the cutting process are defined as retained teeth.

[0076] (1) Starting from the origin x0 = 0, first You can get x n The expression Where n ≥ 1, find the first n such that x n -x0≥Δ, it is concluded that n=N1 at this time, and the abscissa of the end point of the first retained tooth is obtained (The starting point of the first retained tooth has a horizontal coordinate of X0 = 0). Then set x>X1, N 1* t <y<N 1*The material in the overlapping area (t+h) is removed, and the length of the removed area is H1=N1*h (the length of the removed area material is an integer multiple of h, that is, an integer multiple of the 2π phase difference), thereby obtaining the first retained tooth. Since this retained tooth is connected to the crossbeam part, it is defined as a connected tooth, and its length distribution is (0≤x≤X1). Since the length of each final tooth (except the crossbeam part) must be kept at h, it is divided into N1 teeth in the direction of retaining the tooth length, and the length distribution of each final tooth is obtained as

[0077] (2) Then in the region x>X1, according to Find the horizontal coordinate:

[0078]

[0079] If x-X1<Δ, then directly enter (3) and continue to cut the connected teeth. Here, n1 is defined as the number of isolated teeth after the first connected tooth, and the subscript 1 represents the first connected tooth. At this time, n1=0 (indicates that after the first connected tooth is cut, the number of isolated teeth is 0, and directly enter the second connected tooth cutting).

[0080] If x-X1≥Δ, then Will N 1* (t+h) <y<N 1* The material of the overlapping area of ​​(t+h)+N1*h is removed, and the length of the removed area is also H1=N1*h, thus obtaining a new retained tooth. Since this retained tooth has no crossbeam area connected to it, it is defined as an isolated tooth. It is the first isolated tooth after the first connected tooth, and its horizontal coordinate is The subscript below indicates the first connected tooth, and the superscript above indicates the first isolated tooth, so It represents the abscissa of the end point of the first isolated tooth after the first connected tooth, and its starting point abscissa is The total length of this isolated tooth The area below this isolated tooth has a beam connected to the first connected tooth, with a length of T1 = N1*t. This ensures that when this isolated tooth is decomposed into N1 teeth, each tooth can be assigned a beam length of t. In this way, this isolated tooth and the beam below form a retained tooth, and the total length distribution of this retained tooth is

[0081] Since the tooth length of each final tooth (excluding the crossbeam) must be kept at h, it is decomposed into N1 final teeth in the direction of retaining the tooth length. The length distribution of each final tooth (including the crossbeam) is

[0082]

[0083] Continue to the next isolated tooth cutting, according to (i>1 and is an integer), the distance Δr between each two horizontal coordinates can be calculated i =x i -x i-1 , if Δr i ≥Δ, then the horizontal coordinate of the ith isolated tooth after the first connected tooth is obtained Will N 1* (t+h)+N1*(i-1)*h <y<N 1* The material in the overlapping area of ​​(t+h)+i*N1*h is removed, and the length of the removed area is H1=N1*h. At this time, the i-th isolated tooth after the first connected tooth is obtained, and its starting point abscissa is The abscissa of the end point is The total length of this isolated tooth is There is a beam connected to the first connected tooth in the lower area, with a length of T1 = N1*t beam, which ensures that when the ith isolated tooth is decomposed into N1 teeth, each tooth can be assigned a beam length of t. This isolated tooth and the beam below form a reserved tooth, that is, the reserved tooth corresponding to the ith isolated tooth, and its total length distribution is Since the tooth length of each final tooth (excluding the crossbeam) must be kept at h, it is divided into N1 final teeth in the direction of retaining the tooth length. The length distribution of each final tooth is

[0084]

[0085] This expression also applies to the case where i=1. In this case,

[0086] Define the last isolated tooth that meets the requirements after the first connected tooth as the i=n1th (n1≥0, if there is no isolated tooth that meets the conditions, then n1=0, and directly enter (3) to cut the connected teeth. Similarly, in the following, n i It is defined as the number of isolated teeth that meet the requirements after the i-th connected tooth).

[0087] (3) Until the n1+1th, The previous isolated tooth acquisition strategy is no longer continued, and the connected tooth acquisition strategy is changed to.

[0088] according to (m≥1), which is equivalent to adding one more h, adding one more t, and finding the first x m Make it and the end point coordinate of the last retained tooth (connected tooth or isolated tooth) The difference ≥ Δ, at this time m = m2, N2 = N1 + m2 (where m2 is defined as the number of final teeth that the second connected tooth has more than the first connected tooth after decomposition. Similarly, in the following text, m i is defined as the number of final teeth that the i-th connected tooth has more than the (i - 1)-th connected tooth after decomposition, i > 1), thus obtaining the end coordinates of the second connected tooth

[0089] Remove the material in the overlapping area where x > X2, N1*(h + t) + n1*N1*h + m2*t < y < N1*(h + t) + n1*N1*h + (N1 + m2)*h + m2*t, and the second connected tooth will be obtained. The length of the removed area is: H2 = N2*h = (N1 + m2)*h, that is, the length of each cut area is an integer multiple of h, or an integer multiple of 2π phase difference, which will not damage the phase matching; in The remaining material length distribution in the area is: To keep the tooth length of each tooth as h (excluding the crossbeam), decompose y2 into N1 + m2 teeth, which are divided into two categories:

[0090] The first category: N1 identical teeth, with a tooth length of h, and there are N1 crossbeam lengths connected by the first connected tooth below. Each tooth can obtain one crossbeam, so the length distribution of each of these N1 teeth is:

[0091]

[0092] where y2(1) represents the length distribution of the first-category teeth of the second connected tooth

[0093] The second category: m2 identical teeth. These m2 teeth do not use the crossbeams below, but use the crossbeams connected to the second connected tooth. The length distribution of each tooth is:

[0094]

[0095] Among them, the case where x - X1 < Δ in (2) is equivalent to the case where n1 = 0 here

[0096] (4) And so on. Whenever a connected tooth is intercepted, start intercepting isolated teeth until the tooth width of the isolated teeth does not meet the requirements, then start intercepting connected teeth again until the required aperture is obtained

[0097] Taken together, it can be summarized as: The i-th connected tooth can be divided into N i + m i final teeth, and the total length distribution is

[0098]

[0099] The first type N i The final tooth of the beam combination connected to the 1st connected tooth to the i-1th connected tooth below, the length distribution of each tooth is:

[0100]

[0101] The second type i The final tooth is formed by using only the beam connected to the i-th connected tooth, and the length distribution of each tooth is:

[0102]

[0103] The total length distribution of the jth isolated tooth following the i-th connected tooth is:

[0104] Divide the jth isolated tooth into N i The length distribution of each final tooth is:

[0105]

[0106] (i>0 and is an integer, j>0 and is an integer).

[0107] example:

[0108] like Figure 5-6 As shown, this is the case where N1=1, n1=0, N2=2, n2=1, m2=1, N3=3, m3=1, and the shaded part is the removed material (wherein, h=35.05μm, λ=2.4796e-05μm, δ=7.07395e-7, Δ=20μm).

[0109] Although the specific embodiments of the present invention are disclosed for the purpose of illustration, the purpose is to help understand the content of the present invention and implement it accordingly, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the best embodiment, and the scope of the present invention is subject to the scope defined in the claims.

Claims

1. A large-aperture ultra-low absorption Kinoform lens, characterized in that: It includes a plurality of final teeth with a tooth length of h arranged side by side along the x-axis, and each of the final teeth is symmetrically distributed along the y-axis; wherein the x-axis direction is the aperture direction, and the y-axis direction is the X-ray incident direction; m ≥ 1 and is an integer, λ is the wavelength of X-rays, δ is the refractive index of X-rays in the material, The designed tooth length h in the y direction is the material length that causes a phase difference of 2πm.

2. A design method for a large-aperture ultra-low absorption Kinoform lens, comprising the following steps: 1) Establishing a surface model of the large-aperture ultra-low absorption Kinoform lens according to the design focal length f of the large-aperture ultra-low absorption Kinoform lens Among them, the x direction is the aperture direction, the y direction is the X-ray incident direction, and the z direction is the thickness direction; the designed tooth length in the y direction is m ≥ 1 and is an integer, λ is the wavelength of X-rays, δ is the refractive index of X-rays in the material, and the minimum tooth width that can be processed in the x direction in actual processing is Δ; 2) Based on the face model Calculate the horizontal coordinate whose height is an integer multiple of h Where i ≥ 0 and is an integer; 3) For the lens structure of x>0: Starting from the origin x0=0, find the first i -x0≥Δ coordinate point x i , we can conclude that i=N1 at this time, In the face The material overlapping the area 0≤y≤N1*h is removed to obtain the first retained tooth. x0 is the abscissa of the starting point of the first retained tooth. The abscissa of the end point of the first retained tooth and the width of the first retained tooth Length L1 = N1*h, length distribution Continue to find the first one that makes The coordinate point x i , we can conclude that i=N2 at this time, In the face The material in the overlapping area with N1*h≤y≤N2*h is removed to obtain the second retained tooth. is the starting point abscissa of the second retained tooth, The abscissa of the end point of the second retained tooth and the width of the second retained tooth Length L2 = N2*h, length distribution And so on, find the first The coordinate point x i , we can conclude that i=N j , In the face With N j-1 *h≤y≤N j *h The material of the overlapping area is removed to obtain the jth retained tooth; where, is the abscissa of the starting point of the jth retained tooth, is the abscissa of the end point of the jth retained tooth, and the width of the jth retained tooth Length L j =N j *h, length distribution Cut in the above manner until the lens aperture reaches the required size; 4) According to the axial symmetry and step 3), calculate the lens structure of the part x<0; 5) According to the designed tooth length h, the retained teeth obtained in steps 3) and 4) are decomposed into a number of final teeth with a tooth length of h in the length direction; the final teeth obtained are arranged side by side along the x-axis to obtain a large-aperture ultra-low absorption Kinoform lens.

3. The method according to claim 2, characterized in that In step 5), for the length L j =N j *h's jth retained tooth, decompose it into N in the length direction j final teeth, each final tooth has a length of h and a width of W j , the length distribution of each final tooth is 4. A design method for a large-aperture ultra-low absorption Kinoform lens, comprising the following steps: 1) Establishing a surface model of the large-aperture ultra-low absorption Kinoform lens according to the design focal length f of the large-aperture ultra-low absorption Kinoform lens Among them, the x direction is the aperture direction, the y direction is the X-ray incident direction, and the z direction is the thickness direction; the designed tooth length in the y direction is m ≥ 1 and is an integer, λ is the wavelength of X-rays, δ is the refractive index of X-rays in the material, the minimum tooth width that can be processed in the x direction in actual processing is Δ, and the length of the beam in the y direction is t; 2) For the lens structure of x>0: 21) Starting from the origin x0=0, according to Find the first n such that x n -x0≥Δ, we can conclude that n=N1 at this time, and then add x>X1 and N 1* t <y<N 1* The material in the overlapping area (t+h) is removed to obtain the first connected tooth, whose end point abscissa The starting point abscissa X0 = 0; the length distribution of the first connected tooth is According to the designed tooth length h, the first connected tooth is divided into N1 final teeth, and the length distribution of each final tooth is 22) In the region x>X1, according to Find the horizontal coordinate If x-X1<Δ, directly go to 23) to continue cutting the connected teeth. At this time, the number of isolated teeth after the first connected tooth n1=0; If x-X1≥Δ, perform isolated tooth cutting: Will With N 1* (t+h) <y<N 1* The material in the overlapping area of ​​(t+h)+N1*h is removed to obtain the first isolated tooth. The abscissa of the end point of the first isolated tooth is The horizontal coordinate of the starting point is Overall length The area below the first isolated tooth has a crossbeam with a length of T1=N1*t connected to the first connected tooth, which is used to decompose the first isolated tooth into N1 final teeth with a designed tooth length of h, and each final tooth is assigned a crossbeam with a length of t in the y direction; the first isolated tooth and the crossbeam below it form a reserved tooth, and its length distribution is According to the designed tooth length h, the retained tooth is decomposed into N1 final teeth including the crossbeam. The length distribution of each final tooth including the crossbeam is: Continue to the next isolated tooth cutting, according to Calculate the distance Δr between each two horizontal coordinates i =x i -x i-1 , i>1 and is an integer; if Δr i ≥Δ, then the horizontal coordinate of the ith isolated tooth after the first connected tooth is obtained Will With N 1* (t+h)+N1*(i-1)*h <y<N 1* The material in the overlapping area of ​​(t+h)+i*N1*h is removed to obtain the i-th isolated tooth after the first connected tooth, and its starting point abscissa is The abscissa of the end point is The total length is The area below the ith isolated tooth has a beam connected to the first connected tooth with a length of T1=N1*t. When the ith isolated tooth is decomposed into N1 final teeth, each final tooth is assigned a beam with a length of t in the y direction. The ith isolated tooth and the beam below form a reserved tooth, and its length distribution is According to the designed tooth length h, the retained tooth corresponding to the ith isolated tooth is divided into N1 final teeth, and the length distribution of each final tooth is When the n1+1th isolated tooth is calculated, When , stop acquiring isolated teeth and execute step 23); 23) Cutting of connected teeth according to Find the first x m So that it and the end point coordinates of the n1th isolated tooth The difference is ≥Δ, at this time m=m2, N2=N1+m2, and the abscissa of the end point of the second connected tooth is obtained. x>X2 and N1*(h+t)+n1*N1*h+m2*t <y<N1*(h+t)+n1*N1*h+ The material in the overlapping area of ​​(N1+m2)*h+m2*t is removed to obtain the second connected tooth. Distribution of material length remaining in the area According to the designed tooth length h, y2 is decomposed into N1+m2 final teeth, including two types of final teeth: The first type of final teeth: N1 final teeth with the same design tooth length h, below which there are N1 beams with a length of t in the y direction connected to the first connecting tooth. The length distribution of each final tooth in the N1 final teeth is The second type of final teeth: m2 final teeth with the same design tooth length h, and m2 beams with a length of t in the y direction connected to the second connected tooth are used below them. The length distribution of each final tooth in the m2 final teeth is 24) Similarly, after the connected teeth are cut, isolated teeth are cut. When the tooth width of the isolated teeth does not meet the requirements, connected teeth are cut again until the required caliber is obtained.

5. The method according to claim 4, characterized in that The i-th connected tooth is divided into N i +m i The total length distribution of the final teeth is N i The length distribution of each final tooth in the final teeth of the beam combination connecting the first-type final teeth and the first connected teeth to the i-1th connected teeth below is m i The length distribution of each final tooth in the final teeth of the second type final teeth combined with the beam connected to the i-th connected tooth is The total length distribution of the jth isolated tooth following the i-th connected tooth is: The length distribution of each final tooth obtained by dividing the jth isolated tooth is: i>0 and is an integer, j>0 and is an integer.

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