JP2009240378A - X-ray imaging apparatus and method of manufacturing slit member used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray imaging apparatus which is manufactured inexpensively and uses the multi-slit of high accuracy and a high aspect ratio, in the field of a high sensitivity X-ray imaging method by an X-ray Talbot-Lau interferometer. <P>SOLUTION: An X-ray generation source 1 irradiates a slit member 2 with the required amount of X-rays. The slit member 2 is provided with a low absorption material 21 of a low X-ray absorption amount and a high absorption material 22 of an X-ray absorption amount larger than that of the low absorption material 21, and the low absorption material 21 and the high absorption material 22 are extended practically in the same direction. Further, the low absorption material 21 and the high absorption material 22 are alternately laminated with a prescribed pitch. The slit member 2 is disposed in such a way that the extending directions of the low absorption material 21 and the high absorption material 22 cross the advancing direction of X-rays irradiated from the X-ray generation source 1. A first grating 3 diffracts the X-ray transmitted by the slit member 2. A second grating 4 diffracts the X-ray diffracted in the first grating 3. An X-ray image detector 5 detects the X-rays diffracted in the second grating 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an X-ray imaging apparatus for observing the internal structure of a subject with high sensitivity using the phase of X-rays.

  Since X-rays have high penetrating power, they are widely used in medical image diagnosis, non-destructive inspection, security check and the like as a probe for seeing through the inside of an object. The contrast of an X-ray fluoroscopic image depends on the difference in X-ray attenuation rate, and an object that strongly absorbs X-rays is rendered as an X-ray shadow. X-ray absorption ability becomes stronger as more elements with larger atomic numbers are included. Conversely, it can be pointed out that a substance composed of an element with a small atomic number is difficult to contrast, and this is also a principle defect of an X-ray fluoroscopic image. Therefore, sufficient sensitivity cannot be obtained with respect to biological soft tissue or soft material.

  On the other hand, it is known that the use of X-ray phase information realizes a sensitivity increase of up to about three digits compared to a general conventional X-ray fluoroscopic image. Since it can be applied to the observation of substances (light body soft tissues, organic materials, etc.) made of light elements that do not absorb X-rays very much, their practical use is expected.

  Research on high-sensitivity imaging using this X-ray phase information is a field that has been around for about 15 years, but since an advanced X-ray source is usually required, its practical use is not practical. Not progressing. That is, X-ray optical systems that use monochromatic plane wave X-rays have been studied as the mainstream, and it is therefore premised on the use of an extremely high-brightness X-ray source.

  In order to obtain a monochromatic plane wave, it is necessary to select only a specific spectral component traveling in a specific direction from the originally obtained X-ray. Therefore, in order to ensure the intensity necessary for imaging, the original X-ray is required to have sufficient brightness to compensate for the loss due to sorting. A single crystal such as silicon is used as such an optical element, but at the same time, the use of a huge synchrotron radiation facility must be essentially assumed, which is a major obstacle when considering practical use. .

  If a phase-based imaging method that functions with a wide-band cone beam is realized, an apparatus using a compact X-ray source other than synchrotron radiation can be expected. As a candidate for such an imaging method, an X-ray phase imaging method using an X-ray Talbot interferometer is expected (see Patent Documents 1 and 2 below). In this method, since an X-ray lattice is used instead of a single crystal, imaging using multi-colored divergent beam X-rays is possible.

  However, in the phase-based imaging method, a certain degree of spatial coherence is required for X-rays. For this purpose, the size of the X-ray generation source must be small to some extent. Then, even if it is a compact X-ray source, an existing X-ray source that can be used in this method is substantially a microfocus X-ray source. This does not apply to normal focus X-ray sources.

  In the microfocus X-ray source, X-rays are generated by irradiating a minute region on the target T with an electron beam EB as shown in FIG. However, except for the case where a long exposure time is allowed, there is a problem that the power of the X-ray obtained by the microfocus X-ray source is insufficient for application to X-ray imaging.

  In the conventional X-ray Talbot-Lau interferometer, a normal focus X-ray source is used to avoid the problem of insufficient intensity. The configuration of the X-ray Talbot-Lau interferometer is a multi-slit added to the configuration of the X-ray Talbot interferometer. That is, in this technique, an X-ray is generated by irradiating a relatively large area of the target with an electron beam, and the generated X-ray is partially transmitted through a multi slit. As a result, it is possible to realize a radiation source in which narrow and linear virtual X-ray sources are arranged at a predetermined pitch. Such a radiation source having a plurality of micro lines may be referred to as a micro multi-line radiation source.

  The X-rays from each slit in the multi-slit individually operate the downstream X-ray Talbot interferometer. By determining the interval between the multi slits so that the moire fringes generated by the X-rays from the respective slits are shifted by one period and overlapping, phase information detection based on the principle of the X-ray Talbot interferometer becomes possible.

  However, the multi-slit needs to have a sufficient thickness in order to guarantee the function of the portion where X-rays should be blocked. Moreover, the multi-slit needs to have a slit width of about 10 microns at intervals of several tens of microns. For this reason, the multi-slit has a high aspect ratio structure and is difficult to manufacture. Furthermore, since X-rays spread radially from the generation source, an X-ray multi-slit having a high aspect ratio should ideally have a cylindrical shape with the X-ray source as the center of curvature. This also makes it difficult to produce multi-slits.

In order to create an X-ray multi-slit having a high aspect ratio, it is conceivable to use a lithography technique. However, even if lithography technology is used, it is generally considered to be quite difficult to produce a multi-slit with a high aspect ratio and high accuracy.
International Publication WO2004 / 058070 U.S. Pat. No. 5,821,629

  The present invention has been made in view of the above circumstances. One object of the present invention is to provide an X-ray imaging apparatus using a multi-slit with high accuracy and high aspect ratio.

  Another object of the present invention is to provide a method for manufacturing a high-precision and high-aspect ratio multi-slit used in an X-ray imaging apparatus.

  The present invention can be expressed as an invention described in the following items.

(Item 1)
An X-ray generation source, a slit member, a first grating, a second grating, and an X-ray image detector;
The X-ray generation source is configured to irradiate a necessary amount of X-rays toward the slit member,
The slit member includes a low absorption material having a low X-ray absorption amount and a high absorption material having a higher X-ray absorption amount than the low absorption material,
The low absorbent material and the high absorbent material are extended in substantially the same direction,
Furthermore, the low absorbent material and the high absorbent material are alternately and laminated at a predetermined pitch,
The slit member is arranged so that the extending direction of the low-absorbing material and the high-absorbing material intersects the traveling direction of X-rays irradiated from the X-ray generation source,
The first grating is configured to diffract the X-ray transmitted through the slit member,
The second grating is configured to diffract the X-ray diffracted by the first grating,
The X-ray image detector is configured to detect X-rays diffracted by the second grating.

  In this invention, since the low absorption material and the high absorption material in the slit member are laminated at a predetermined pitch, a plurality of line-shaped X-rays separated at a predetermined pitch can be obtained. By irradiating such a linear X-ray on the first grating, the apparatus of the present invention can perform the same operation as a conventional X-ray Talbot-Lau interferometer.

  According to the present invention, since the low-absorbing material and the high-absorbing material are laminated, the accuracy of the pitch of the line-shaped X-rays can be increased without using a photolithography technique.

  In the present invention, the low absorption material and the high absorption material in the slit member are laminated at a predetermined pitch, so that a high aspect ratio can be realized relatively easily as compared with the case of using a photolithography technique. Can do. This facilitates realization of high contrast in X-ray imaging.

(Item 2)
The X-ray imaging apparatus according to Item 1, wherein the slit member is curved so as to have a substantially cylindrical surface shape in which the side of the X-ray generation source is concave.

  In general, X-rays from an X-ray generation source travel radially around the X-ray generation source. Then, the X-ray contrast tends to decrease in the vicinity of both ends of the projection angle. On the other hand, in the invention described in Item 2, it is easy to realize high contrast, particularly at a position away from the optical axis.

(Item 3)
The X-ray imaging apparatus according to Item 1 or 2, wherein the low absorption material has a function of adhering adjacent high absorption materials to each other.

  By giving the low absorbent material an adhesive function between the high absorbent materials, the low absorbent material and the high absorbent material can be easily fixed, and the slit member can be easily manufactured.

(Item 4)
The X-ray imaging apparatus according to Item 1 or 2, wherein the high absorption material has a function of adhering adjacent low absorption materials to each other.

  By giving the high absorbent material an adhesive function between the low absorbent materials, the low absorbent material and the high absorbent material can be easily fixed, and the manufacture of the slit member is simplified.

(Item 5)
The X-ray imaging apparatus according to any one of Items 1 to 4, wherein the low absorption material and the high absorption material are both formed to have a uniform thickness.

  By increasing the accuracy of the thicknesses of the low absorption material and the high absorption material, it is possible to improve the accuracy of the pitch of the line-shaped X-rays.

(Item 6)
3. The X-ray imaging apparatus according to item 1 or 2, wherein the low absorption material is configured by an adhesive that bonds the high absorption materials together.

  By using the low absorbent material as an adhesive that bonds the high absorbent materials together, the low absorbent material and the high absorbent material can be easily fixed, and the slit member can be easily manufactured. Moreover, when the low absorbent material is used as an adhesive, the accuracy of the thickness of the low absorbent material in the completed state can be increased by controlling the coating amount and drying conditions.

(Item 7)
One or both of the said low absorption material and the said high absorption material are comprised by the material which can deform | transform with external force, The X-ray imaging device of any one of the items 1-6 characterized by the above-mentioned. .

  By configuring at least one of the low-absorbing material and the high-absorbing material with a material that easily deforms, the work of bending the slit member can be easily performed. If the slit member is used as a flat plate, it may be difficult for the X-ray to pass through the edge of the slit member when radiating X-rays, and the imaging field of view may be limited. By curving the slit member in a circular arc shape, the entire surface of the slit member can be made to pass X-rays equally, and the above-mentioned worry is unnecessary.

(Item 8)
A method for manufacturing a slit member used in an X-ray imaging apparatus, comprising the following steps:
(1) A step of alternately laminating a low absorption material having a low X-ray absorption amount and a high absorption material having a higher X-ray absorption amount than the low absorption material;
(2) fixing the relative position in the stacking direction of the laminated low absorbent material and the high absorbent material;
(3) The step of configuring the slit member by cutting the laminated low absorbent material and the high absorbent material substantially along the lamination direction.

  According to the invention of this item, a slit member having a high-precision pitch and a high aspect ratio can be manufactured relatively easily.

(Item 9)
The method according to item 8, wherein the fixing in the step (2) is performed by fixing the periphery of the laminated low absorbent material and the high absorbent material.

(Item 10)
The immobilization in the step (2) is the manufacturing method according to item 8, which is performed by adhering the laminated low absorbent material and the high absorbent material.

(Item 11)
An X-ray imaging method using the X-ray imaging apparatus according to any one of Items 1 to 7, including the following steps:
(1) A step of generating a plurality of line-shaped X-rays from the slit member by irradiating the slit member with the X-ray from the X-ray generation source;
(2) the first grating diffracts the linear X-ray generated from the slit member;
(3) the second grating diffracts the X-rays diffracted by the first grating;
(4) A step in which the X-ray image detector detects X-rays diffracted by the second grating.

(Item 12)
A slit for partially transmitting X-rays generated from an X-ray generation source in an X-ray imaging apparatus,
A low-absorbing material having a low X-ray absorption amount, and a high-absorbing material having a higher X-ray absorption amount than the low-absorbing material,
The low absorbent material and the high absorbent material are extended in substantially the same direction,
Furthermore, the low absorbent material and the high absorbent material are alternately and laminated at a predetermined pitch,
The slit characterized by the extending direction of the said low absorption material and the said high absorption material being arrange | positioned so that the advancing direction of the X-ray irradiated from the said X-ray generation source may be crossed.

  According to the present invention, it is possible to provide an X-ray imaging apparatus using a multi-slit with high accuracy and high aspect ratio.

  Further, according to the present invention, an X-ray imaging apparatus based on the principle of X-ray phase imaging using a Talbot-Lau interferometer can be provided, so that highly sensitive imaging is possible.

  Furthermore, according to the present invention, it is possible to provide a method for manufacturing a high-precision and high-aspect ratio multi-slit used in an X-ray imaging apparatus.

(Configuration of X-ray imaging apparatus in the first embodiment)
The configuration of the X-ray imaging apparatus according to the first embodiment of the present invention will be described with reference mainly to FIG. This X-ray imaging apparatus includes an X-ray generation source 1, a slit member 2, a first grating 3, a second grating 4, and an X-ray image detector 5 as main components.

  The X-ray generation source 1 is configured to irradiate the slit member 2 with a necessary amount of X-rays, and a general X-ray generation source can be used. The X-ray generation source 1 includes a target material and an excitation beam source (not shown). The X-ray generation source 1 is formed by a configuration that generates X-rays by irradiating a target material with an excitation beam. The specifications of the target material and the excitation beam are selected according to the required X-ray wavelength and dose. In general, the target material is often a metal such as tungsten or molybdenum, but is not limited thereto.

  The slit member 2 includes a low-absorbent material 21 having a low X-ray absorption amount, a high-absorbent material 22 having a higher X-ray absorption amount than the low-absorbent material 21, and a frame 23 (FIGS. 2 and 3). reference).

  The low absorbent material 21 and the high absorbent material 22 are both formed to have a uniform thickness. Further, the low absorbent 21 and the high absorbent 22 are extended in substantially the same direction (the thickness direction of the paper surface in FIG. 2). That is, the longitudinal direction of the low absorbent material 21 and the high absorbent material 22 is arranged to be the thickness direction of the paper surface in FIG.

  Furthermore, the low absorbent material 21 and the high absorbent material 22 are alternately laminated at a predetermined pitch.

  In the slit member 2, the extending direction of the low-absorbent material 21 and the high-absorbent material 22 (the thickness direction of the paper surface in FIG. 2) is the traveling direction of X-rays irradiated from the X-ray generation source (from left to right in FIG. 1). It is arranged so as to intersect with the direction. More specifically, in this embodiment, the slit member 2 is such that the projection (that is, the projected image) from the slit member 2 onto the surface of the first grating 30 is substantially parallel to the grating member constituting the first grating 30. 2 is placed.

  As the low absorption material 21, for example, a polymer film or a light metal foil can be used. The polymer is, for example, a polyimide film. The light metal is, for example, aluminum, but a metal having a small atomic number can be appropriately selected. The thickness a of the low absorbent material 21 regulates the interval between the high absorbent materials 22. That is, the thickness a is selected corresponding to the interval between the high absorbent materials 22.

The size of the thickness a is the same as the value required for the size of the light source in the Talbot interferometer. That is, the spatial coherence distance only needs to be approximately the same as the period of the first grating, and the center wavelength of X-ray is λ, and is selected to be approximately equal to or smaller than R ₁ λ / d ₁ .

As the high absorbent material 22, for example, a metal foil having a relatively large atomic number can be used. The thickness b of the high absorbent material 22 is selected so that a + b substantially coincides with the period d _s required for the multi-slit.

  The frame 23 is fixed to the peripheral edges of the low absorbent material 21 and the high absorbent material 22 and fulfills the function of maintaining the laminated state.

The number of layers (slit number) M _s stacked to constitute the slit member 2 is the distance R _s (see FIG. 1) from the X-ray generation source 1 to the slit member 2 and necessary for X-ray imaging. Depends on the visual field. That is,
Need to be. Here, R is the distance from the slit member 2 to the image detector 5. L is the magnitude (distance) of the imaging field angle in the direction in which the low absorbent 21 and the high absorbent 22 are laminated. In the present embodiment, if R _s is small, that is, if the slit member 2 is brought close to the X-ray generation source 1, the size of the slit member 2 can be reduced, which is suitable for downsizing of the apparatus.

  The first grating 3 is configured to diffract the X-ray transmitted through the slit member 2. The second grating 4 is configured to diffract the X-ray diffracted by the first grating 3. Further, the second grating 4 is configured to generate a periodic intensity pattern by X-rays diffracted by the second grating 4. The X-ray image detector 5 is configured to detect X-rays diffracted by the second grating 4.

The first grating 3 is arranged at a predetermined distance R ₁ from the X-ray generation source 1. A second grating 4 is arranged at a distance R ₂ from the first grating 3. A subject (test object; not shown) is generally arranged immediately before the first grid 3. However, in principle, it is sufficient if there is a subject between the slit member 2 and the second lattice 4. The image detector 5 is installed immediately behind the second grating 4.

The relationship between the pitches d ₁ and d _{2 of} the first and second lattices 3 and 4 and R ₁ and R ₂ is as follows:
It is. m is a half integer. However, there is no problem if the actual R ₂ is close to the value given under this condition with an error of several percent. At this time, the period ds of the slit member 2 is
Given in.

  The configurations and positional relationships of the first grating 3, the second grating 4, and the X-ray image detector 5 in the present embodiment are basically the same as those of a conventional Talbot interferometer (for example, the one described in Patent Document 1 described above). It's okay. Therefore, more detailed description of these will be omitted. In the imaging apparatus according to the present embodiment, the slit member 2 is arranged at the position of the X-ray generation source in the conventional Talbot interferometer, and the X-ray generation source 1 (normally focused) is further arranged in a direction away from the grating. Talbot-Lau interferometer (see FIG. 1).

(Operation of the first embodiment)
Next, the operation of the X-ray imaging apparatus of this embodiment will be described. In this apparatus, a subject (not shown) is disposed between the slit member 2 and the X-ray image detector 5. For example, the subject is arranged immediately before the first grid 3 (left side in FIG. 1).

  In this state, X-rays are irradiated from the X-ray generation source 1 toward the slit member 2. Although the irradiated X-rays are substantially transmitted through the low absorption material 21, they are substantially absorbed by the high absorption material 22. In the present embodiment, since the low absorption material 21 and the high absorption material 22 are alternately and periodically arranged, a plurality of line-shaped X-rays separated by a predetermined pitch can be obtained. By irradiating the first grating 3 and the second grating 4 with such a linear X-ray, the same operation as that of a conventional X-ray Talbot-Lau interferometer can be performed.

  In addition, quantitative measurement of phase information using the X-ray imaging apparatus of the present embodiment is possible, and a stereoscopic image can be generated by phase tomography based on the measurement. Since the technique described in the said patent document 1 can be used about this, detailed description is abbreviate | omitted.

  Moreover, according to this embodiment, since it comprises by laminating | stacking the low absorption material 21 and the high absorption material 22, one exhibits the positioning effect | action about the other. For this reason, this embodiment has an advantage that the accuracy of the pitch of the line-shaped X-rays can be increased without using a photolithography technique.

  Furthermore, in this embodiment, since the slit member 2 is formed by laminating the low-absorbent material 21 and the high-absorbent material 22 and then cutting, the aspect ratio is higher than that in the case of using the photolithography technique. It can be realized relatively easily. This has an advantage that high-sensitivity X-ray imaging can be easily realized.

(Manufacturing method of slit member)
Next, the manufacturing method of the slit member 2 used in this embodiment will be described based on FIG.

(Fig. 3 (a))
First, the laminated body is formed by alternately laminating the low-absorbent material 21 and the high-absorbent material 22 each formed in a sheet shape.

(Fig. 3 (b))
Next, the laminated body of the low absorbent material 21 and the high absorbent material 22 is sandwiched between the flat surfaces of the metal blocks 71 and 72. Thereafter, the metal blocks 71 and 72 are pressed together to compress the laminate.

(Fig. 3 (c) and (d))
Thereafter, the enclosure member 8 is disposed around the laminate and the metal blocks 71 and 72. Furthermore, the inside of the enclosure member 8 is filled with the melted solder 9, and returned to room temperature and cured. Thereby, the said laminated body can be fixed. That is, in the present embodiment, the laminated body of the low absorbent material 21 and the high absorbent material 22 is fixed by fixing the periphery thereof. However, the means for fixing the periphery is not limited to solder, and other means such as resin can be used.

  Furthermore, in this embodiment, these processes are basically performed while maintaining the compressed state of the low absorbent material 21 and the high absorbent material 22. This prevents a gap from being generated between the low absorbent material 21 and the high absorbent material 22.

(Fig. 3 (e))
Next, the laminated low-absorbent material 21 and high-absorbent material 22 are cut along with the solder 9 and the metal blocks 71 and 72 substantially along the stacking direction (that is, in the vertical direction in FIG. 3) and cut into a plate shape. It's out. Next, by polishing the cut surface, a portion broken by the cutting can be removed and the thickness can be reduced to a desired thickness. In this way, the slit member 2 can be manufactured. At this time, the cut solder 9 and the metal blocks 71 and 72 become the frame 23 of the slit member 2.

  In the manufacturing method of this embodiment, the aspect ratio in the slit member 2 can be controlled by changing the width of cutting the laminated low absorbent material 21 and high absorbent material 22. Moreover, since it is easy to increase the cutting width of the low absorbent material 21 and the high absorbent material 22, the slit member 2 having a high aspect ratio can be easily manufactured.

  Moreover, in the manufacturing method of the present embodiment, by laminating the low absorbent material 21 and the high absorbent material 22, one of them exerts a positioning action for the other, so that the pitch accuracy in these arrangements can be increased. .

  Therefore, according to the manufacturing method of this embodiment, there is an advantage that the slit member 2 having a high precision pitch and a high aspect ratio can be manufactured relatively easily.

  Moreover, in this embodiment, since both the low absorption material 21 and the high absorption material 22 were formed in uniform thickness, by setting these layers, the mutual positional relationship can be set accurately and easily. Can do.

  Furthermore, in this embodiment, since the slit part 2 is obtained by cutting the sheet-like low absorbent 21 and the high absorbent 22 in the laminated state, the slit part 2 having the same configuration is manufactured at low cost. There is also an advantage of being able to.

(Second Embodiment)
Next, an X-ray imaging apparatus according to a second embodiment of the present invention will be described based on FIG. In the description of the second embodiment, components that are basically the same as those in the first embodiment described above are denoted by the same reference numerals, and the description is simplified.

  In the apparatus of the first embodiment described above, the slit member 2 is formed in a flat plate shape (see FIG. 1). On the other hand, the slit member 2 of the apparatus of the second embodiment is curved so as to form a substantially cylindrical surface shape in which the X-ray generation source 1 side is concave. That is, the slit member 2 is curved so as to form a cylindrical surface shape with a virtual axis (not shown) substantially parallel to the extending direction of the low absorbent 21 and the high absorbent 22 as the center of curvature ( (See FIG. 4). Here, the above-mentioned virtual axis is a straight line extending in the thickness direction of the paper surface in FIG. The position of the imaginary axis is on the side of the X-ray generation source 1 (left side in FIG. 4) when viewed from the slit member 2 and substantially coincides with the position of the X-ray generation source 1.

  X-rays from the X-ray generation source 1 travel radially around the X-ray generation source 1. Then, if the slit member 2 is a flat plate, X-rays are incident on the low absorption material 21 or the high absorption material 22 from an oblique direction at the edge of the slit member 2. At this time, there may be a problem that X-rays cannot sufficiently pass at this place. On the other hand, in the invention described in the second embodiment, since the slit member 2 is curved, the X is low with respect to the low absorbent 21 or the high absorbent 22 (more specifically, the facing surfaces thereof). The lines can be incident substantially parallel. For this reason, according to the apparatus of this embodiment, sufficient X-rays pass particularly at a position away from the optical axis, and X-ray contrast is generated by the first grating 3 and the second grating 4 downstream. The first grating 3 and the second grating 4 are desirably curved for the same reason as the slit member 2. However, the radius of curvature required for the curvature of the slit member 2 is considerably larger than that of the slit member 2 (that is, only a gentle curvature is required), and in many cases, it can be used even in a flat plate shape as shown in FIG.

  Other configurations and advantages of the X-ray imaging apparatus according to the second embodiment are the same as those of the first embodiment described above, and a detailed description thereof will be omitted.

(Modification 1)
In each of the embodiments described above, the low absorbent material 21 and the high absorbent material 22 are fixed using the frame 23. However, the low absorbent 21 may be provided with a function of bonding adjacent high absorbents 22 together. For example, such a function can be imparted to the low absorbent material 21 by applying an adhesive to both surfaces of the low absorbent material 21. By providing the low absorbent 21 with the function of bonding the high absorbent 22 to each other, the low absorbent 21 and the high absorbent 22 can be easily fixed, and the slit member 2 can be manufactured easily. It is also considered possible to omit the frame 23.

  Further, the high absorbent material 22 can be provided with a function of bonding adjacent low absorbent materials 21 together.

(Modification 2)
The low absorbent material 21 can be composed of an adhesive that bonds the high absorbent material 22 together. By using the low absorbent 21 as an adhesive that bonds the high absorbent 22 together, the low absorbent 21 and the high absorbent 22 can be easily fixed, and the slit member 2 can be manufactured easily. Moreover, when the low absorbent material 21 is used as an adhesive, the accuracy of the thickness of the low absorbent material 21 in the completed state can be increased by controlling the application amount and drying conditions. Furthermore, according to the second modification, it can be considered that the frame 23 can be omitted.

(Modification 3)
In order to easily curve the slit member 2, one or both of the low absorbent material 21 and the high absorbent material 22 can be made of a material that is easily deformed by an external force. Examples of this include elastic polymer films and adhesives, and even metal foils are applicable if they are relatively soft metal foils.

(Experimental example)
Experimental results obtained with the apparatus of the first embodiment described above are shown in FIGS. FIG. 5 is an image of the slit member 2 observed with an optical microscope. FIG. 6 is an image when the slit member 2 is seen through with X-rays. FIG. 7 is a phase shift differential image acquired by an X-ray imaging apparatus using the slit member 2. The experimental conditions in FIG. 7 are as follows.

(Experimental conditions)
X-ray used: Rigaku Corporation UltraX-MX2; molybdenum target (rotating anti-cathode); focus size 1.0 mm x 0.5 mm; 30 keV, 30 mA,
Low absorbing material in slit member: aluminum (Al); thickness 10 μm,
Superabsorbent material in slit member: Tantalum (Ta); thickness 20 μm,
First grating period: 4.5 microns,
Second grating period: 5.3 microns,
Sample (subject): a plastic sphere having a void inside and a diameter of about 8 mm; placed just before the first grid.

  Since the acquisition procedure of the phase shift differential image shown in FIG. 7 is the same as that described in Patent Document 1, detailed description thereof is omitted.

  Note that the description of the embodiment and the examples is merely an example, and does not indicate a configuration essential to the present invention. The configuration of each part is not limited to the above as long as the gist of the present invention can be achieved.

It is explanatory drawing for demonstrating the schematic structure of the X-ray imaging device which concerns on 1st Embodiment of this invention. It is an enlarged view of the slit member in FIG. It is explanatory drawing for demonstrating the method to manufacture the slit member of FIG. It is explanatory drawing for demonstrating the schematic structure of the X-ray imaging device which concerns on 2nd Embodiment of this invention. It is a figure which shows the image which observed the slit member with the optical microscope. It is a figure which shows the image at the time of seeing through a slit member with a X-ray. It is a phase shift differential image acquired with the X-ray imaging device which concerns on 1st Embodiment. It is explanatory drawing for demonstrating the conventional microfocus X-ray source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray generation source 2 Slit member 21 Low absorption material 22 High absorption material 23 Frame 3 1st grating | lattice 4 2nd grating | lattice 5 X-ray image detector 71 * 72 Metal block 8 Enclosure member

Claims (12)

An X-ray generation source, a slit member, a first grating, a second grating, and an X-ray image detector;
The X-ray generation source is configured to irradiate a necessary amount of X-rays toward the slit member,
The slit member includes a low absorption material having a low X-ray absorption amount and a high absorption material having a higher X-ray absorption amount than the low absorption material,
The low absorbent material and the high absorbent material are extended in substantially the same direction,
Furthermore, the low absorbent material and the high absorbent material are alternately and laminated at a predetermined pitch,
The slit member is arranged so that the extending direction of the low-absorbing material and the high-absorbing material intersects the traveling direction of X-rays irradiated from the X-ray generation source,
The first grating is configured to diffract the X-ray transmitted through the slit member,
The second grating is configured to diffract the X-ray diffracted by the first grating,
The X-ray image detector is configured to detect X-rays diffracted by the second grating. The X-ray imaging apparatus according to claim 1, wherein the slit member is curved so as to form a substantially cylindrical surface shape in which the side of the X-ray generation source is concave. The X-ray imaging apparatus according to claim 1, wherein the low absorption material has a function of adhering adjacent high absorption materials to each other. The X-ray imaging apparatus according to claim 1, wherein the high absorption material has a function of adhering adjacent low absorption materials to each other.   The X-ray imaging apparatus according to claim 1, wherein both the low absorption material and the high absorption material are formed to have a uniform thickness. The X-ray imaging apparatus according to claim 1, wherein the low absorption material is configured by an adhesive that adheres the high absorption materials to each other. One or both of the said low absorption material and the said high absorption material are comprised by the material which can deform | transform by external force, X-ray imaging of any one of Claims 1-6 characterized by the above-mentioned. apparatus. A method for manufacturing a slit member used in an X-ray imaging apparatus, comprising the following steps:
(1) A step of alternately laminating a low absorption material having a low X-ray absorption amount and a high absorption material having a higher X-ray absorption amount than the low absorption material;
(2) fixing the relative position in the stacking direction of the laminated low absorbent material and the high absorbent material;
(3) The step of configuring the slit member by cutting the laminated low absorbent material and the high absorbent material substantially along the lamination direction. The method according to claim 8, wherein the fixing in the step (2) is performed by fixing the periphery of the laminated low absorbent material and the high absorbent material. The immobilization in the step (2) is a manufacturing method according to claim 8, wherein the low-absorbing material and the high-absorbing material that are laminated are adhered to each other. An X-ray imaging method using the X-ray imaging apparatus according to claim 1, comprising the following steps:
(1) A step of generating a plurality of line-shaped X-rays from the slit member by irradiating the slit member with the X-ray from the X-ray generation source;
(2) the first grating diffracts the linear X-ray generated from the slit member;
(3) the second grating diffracts the X-rays diffracted by the first grating;
(4) A step in which the X-ray image detector detects X-rays diffracted by the second grating. A slit for partially transmitting X-rays generated from an X-ray generation source in an X-ray imaging apparatus,
A low-absorbing material having a low X-ray absorption amount, and a high-absorbing material having a higher X-ray absorption amount than the low-absorbing material,
The low absorbent material and the high absorbent material are extended in substantially the same direction,
Furthermore, the low absorbent material and the high absorbent material are alternately and laminated at a predetermined pitch,
The slit characterized by the extending direction of the said low absorption material and the said high absorption material being arrange | positioned so that the advancing direction of the X-ray irradiated from the said X-ray generation source may be crossed.