Debugging method of grating phase contrast imaging system based on X-ray array target light source

Abstract

A debugging method for a grating phase contrast imaging system based on an X-ray array target light source comprises: placing a laser emitting mechanism on a guide rail so that the laser emitting mechanism emits a vertical beam and a horizontal beam; placing the X-ray array target light source and an X-ray detector on the guide rail; aligning the center of a light spot formed by the X-rays with a target position of the X-ray detector; adjusting an analyzing grating so that the intersection of the vertical beam and the horizontal beam passes through the center of a first diffraction fringe; adjusting a beam splitting grating so that the intersection of the vertical beam and the horizontal beam passes through the center of a second diffraction fringe; adjusting the relative positions of the X-ray array target light source, the beam splitting grating, the analyzing grating and the X-ray detector to obtain moiré patterns; synchronously rotating and adjusting the beam splitting grating and the analyzing grating to make the moiré patterns vertical; individually adjusting the beam splitting grating and the analyzing grating to maximize the visibility of the moiré patterns, and moving the beam splitting grating along the optical axis to obtain a roughly uniformly distributed light field on the X-ray detector.

Description

Technical Field

[0001] The present invention relates to the field of X-ray imaging, and in particular to a debugging method for a grating phase contrast imaging system based on an X-ray array target light source. Background Art

[0002] X-ray grating phase contrast imaging not only captures information from traditional X-ray absorption imaging, but also provides information about the sample's phase and scattering from the acquired data. For low-atomic-number samples (especially biological samples), the phase shift cross section is approximately three orders of magnitude larger than the absorption cross section, resulting in better imaging contrast for distinguishing smaller density differences. Furthermore, the scattering information is sensitive to inhomogeneous structures. Therefore, these three types of information complement each other and reflect the sample's structural characteristics from three different perspectives.

[0003] In 2006, F. Pfeiffer et al. introduced the Talbot-Lau interferometer (consisting of a microfocus X-ray source, a beamsplitter grating G1, an analyzer grating G2, and an X-ray detector) into an X-ray phase-contrast imaging device. This enabled conventional X-ray sources to be used in X-ray grating phase-contrast imaging, significantly advancing the practicality of X-ray grating phase-contrast imaging. Furthermore, the X-ray Talbot-Lau imaging system reduces the requirements for light source coherence, making grating phase-contrast imaging technology no longer dependent on microfocus and synchrotron radiation sources, a major step forward in the fields of clinical medicine and industrial testing. An X-ray Talbot-Lau imaging system generally consists of an X-ray source, a source grating G0, a beamsplitter grating G1, an analyzer grating G2, and an X-ray detector.

[0004] However, in the traditional three-grating X-ray phase contrast imaging system, since the three gratings are discrete, although the posture of each grating can be adjusted separately so that the three grating lines are parallel to each other, the source grating in the system blocks more than 50% of the X-rays, resulting in low photon utilization, which is not conducive to practical applications. Summary of the Invention

[0005] In response to the above problems, the present invention provides a grating phase contrast imaging system based on an X-ray array target light source and a debugging method thereof, so as to quickly determine the precise posture of the target scribed line in the X-ray array target light source.

[0006] According to a first aspect of the present invention, a debugging method for a grating phase contrast imaging system based on an X-ray array target light source is provided. The grating phase contrast imaging system includes a guide rail and an X-ray array target light source, a beam splitter grating, an analyzer grating, and an X-ray detector sequentially arranged on the guide rail. The debugging method includes:

[0007] Place a laser emitting mechanism on a guide rail, and enable the laser emitting mechanism to emit a vertical beam and a horizontal beam, wherein the vertical beam and the horizontal beam have the same propagation direction, are distributed along the vertical direction, and the horizontal beam is distributed along the horizontal direction, wherein the intersection line of the vertical beam and the horizontal beam is the straight line where the optical axis is located, and the extension direction of the guide rail is parallel to the optical axis;

[0008] Place the X-ray array target light source and the X-ray detector on the guide rail, and align the center of the light outlet of the X-ray array target light source with the target position of the X-ray detector receiving plane;

[0009] Adjusting the postures of the X-ray array target light source and the X-ray detector to align the center of the spot formed by the X-rays emitted by the X-ray array target light source with the target position of the X-ray detector, wherein the optical axis coincides with the trajectory of the X-rays;

[0010] Placing the analyzer grating on the guide rail and adjusting the analyzer grating so that the intersection of the vertical light beam and the horizontal light beam passes through the center of the first diffraction fringe, wherein the first diffraction fringe is generated by the horizontal light beam and the vertical light beam irradiating the analyzer grating;

[0011] Placing the beam splitting grating on the guide rail and adjusting the beam splitting grating so that the intersection line of the vertical light beam and the horizontal light beam passes through the center of the second diffraction fringe, wherein the second diffraction fringe is generated by the horizontal light beam and the vertical light beam irradiating the analyzer grating;

[0012] Adjust the relative positions of the X-ray array target light source, beam splitter grating, analyzer grating, and X-ray detector so that a moiré pattern can be observed on the X-ray detector. The moiré pattern is formed after the X-rays pass through the beam splitter grating and analyzer grating.

[0013] Synchronously rotate and adjust the beam splitter grating and analyzer grating, or rotate and adjust the X-ray source separately, so that the moiré pattern is parallel to the etched groove direction of the beam splitter grating and the grating groove direction of the analyzer grating, so as to ensure that the scribed lines of the target structure in the X-ray array target light source are parallel to the scribed lines of the beam splitter grating and the scribed lines of the analyzer grating;

[0014] The beam splitter grating and the analyzer grating are adjusted individually to maximize the visibility of the moiré pattern. The beam splitter grating is then moved along the optical axis to obtain a roughly uniformly distributed light field on the X-ray detector, completing the optical path debugging.

[0015] According to an embodiment of the present invention, adjusting the postures of an X-ray array target light source and an X-ray detector to align the center of a light spot formed by X-rays with a target position of the X-ray detector includes the following steps:

[0016] S21: adjusting the azimuth angle and height of the X-ray array target light source relative to the X-ray detector so that the center of the light spot coincides with the target position of the X-ray detector;

[0017] S22: moving the X-ray detector and the X-ray array target light source relative to each other along the guide rail, and then adjusting the azimuth angle and height of the X-ray array target light source relative to the X-ray detector so that the center of the light spot coincides with the target position of the X-ray detector;

[0018] S23: Repeat step S22 until the center of the light spot always coincides with the target position of the X-ray detector.

[0019] According to an embodiment of the present invention, placing an analyzer grating on a guide rail and adjusting the analyzer grating so that the intersection of the vertical light beam and the horizontal light beam passes through the center of the first diffraction fringe includes the following steps:

[0020] S31: placing the analyzer grating on the guide rail, and adjusting the analyzer grating in the vertical direction and the horizontal direction respectively so that the optical axis passes through the target area of ​​the analyzer grating;

[0021] S32: rotating the analyzer grating around the Z axis so that the first diffraction fringe remains horizontal; wherein the Z axis represents the direction of the optical axis;

[0022] S33: rotating the analyzer grating about the Y-axis so that the vertical center line of the first diffraction fringe coincides with the vertical light beam; wherein the Y-axis represents the vertical direction;

[0023] S34: rotating the analyzer grating about the X-axis so that the horizontal center of the first diffraction fringe coincides with the horizontal light beam; wherein the X-axis represents the horizontal direction;

[0024] S35: Repeat steps S32 to S34 until the intersection of the vertical light beam and the horizontal light beam always passes through the center of the first diffraction fringe when the analyzer grating moves on the guide rail.

[0025] According to an embodiment of the present invention, placing a beam splitting grating on a guide rail and adjusting the beam splitting grating so that the intersection of the vertical light beam and the horizontal light beam passes through the center of the second diffraction fringe includes the following steps:

[0026] S41: placing the beam splitting grating on the guide rail, and adjusting the beam splitting grating in the vertical direction and the horizontal direction respectively so that the optical axis passes through the target area of ​​the beam splitting grating;

[0027] S42: rotating the beam splitting grating around the Z axis so that the second diffraction fringe remains horizontal; wherein the Z axis represents the direction of the optical axis;

[0028] S43: rotating the beam splitting grating about the Y axis so that the vertical center line of the second diffraction fringe coincides with the vertical light beam; wherein the Y axis represents the vertical direction;

[0029] S44: rotating the beam splitting grating about the X-axis so that the horizontal center line of the second diffraction fringe coincides with the horizontal light beam; wherein the X-axis represents the horizontal direction;

[0030] S45: Repeat steps S42 to S44 until the intersection of the vertical light beam and the horizontal light beam always passes through the center of the second diffraction fringe when the beam splitting grating moves on the guide rail and moves out of the laser emitting mechanism.

[0031] According to an embodiment of the present invention, adjusting the relative positions of an X-ray array target light source, a beam splitting grating, an analyzer grating, and an X-ray detector so that a moiré pattern can be observed on the X-ray detector includes:

[0032] Move the beam splitting grating along the optical axis so that the distance between the center of the beam splitting grating and the target structure of the X-ray array target light source is R;

[0033] Move the analyzer grating along the optical axis so that the distance between the center of the analyzer grating and the center of the beam splitter grating is d;

[0034] The X-ray detector is moved along the optical axis and brought close to the analyzer grating so that a moiré pattern formed by the beam splitting grating and the analyzer grating can be observed on the X-ray detector.

[0035] According to an embodiment of the present invention, synchronously rotating and adjusting the beam splitter grating and the analyzer grating, or independently adjusting the X-ray source, so that the moiré pattern is parallel to the grating grooves of the beam splitter grating and the grating grooves of the analyzer grating, thereby ensuring that the scribed lines of the target structure in the X-ray array target light source are simultaneously parallel to the scribed lines of the beam splitter grating and the scribed lines of the analyzer grating, comprises the following steps:

[0036] S61: Rotate the beam splitter grating and the analyzer grating simultaneously around the Y axis, or rotate and adjust the X-ray source separately, so that the left and right periods of the moiré pattern observed on the X-ray detector are consistent;

[0037] S62: Rotate the beam splitter grating and the analyzer grating simultaneously around the X-axis, or rotate and adjust the X-ray source separately, so that the upper and lower periods of the moiré pattern observed on the X-ray detector are consistent;

[0038] S63: Rotate the beam splitter grating and the analyzer grating simultaneously around the Z axis, or rotate and adjust the X-ray source separately, so that the moiré pattern observed on the X-ray detector is parallel to the grating groove direction of the beam splitter grating and the analyzer grating;

[0039] S64: Repeat steps S61 to S63 so that the moiré pattern observed on the X-ray detector is always parallel to the grating groove direction of the beam splitter grating and the grating groove direction of the analyzer grating, that is, the groove lines of the target structure in the X-ray array target light source are parallel to the groove lines of the beam splitter grating and the analyzer grating.

[0040] According to an embodiment of the present invention, the beam splitter grating and the analyzer grating are individually adjusted to maximize the visibility of the moiré pattern, and then the beam splitter grating is moved along the optical axis to obtain a substantially uniformly distributed light field on the X-ray detector, thereby completing the optical path debugging, including the following steps:

[0041] S71: Adjust the beam splitter grating individually to rotate around the X-axis, the Y-axis, and the Z-axis to achieve the highest visibility of the moiré pattern and fix it in this position;

[0042] S72: The analyzer grating is individually adjusted to rotate around the X axis, the Y axis, and the Z axis so that the moiré pattern is most visible, and fixed at this position;

[0043] S73: Move the beam splitting grating along the optical axis to obtain a roughly uniformly distributed light field on the X-ray detector, completing the optical path debugging.

[0044] According to an embodiment of the present invention, aligning a light outlet of an X-ray array target light source with a center of a receiving plane of an X-ray detector includes:

[0045] Install the X-ray array target light source and the X-ray detector on the guide rails respectively;

[0046] The laser emission mechanism is used to adjust the light outlet of the X-ray array target light source and the center of the X-ray detector receiving plane to the same level along the vertical direction.

[0047] As a second aspect of the present invention, a method for testing a grating phase contrast imaging system based on an X-ray array target light source is also provided, comprising:

[0048] The sample to be tested is placed at the designated sample position in the grating phase contrast imaging system of the debugged X-ray array target light source, and the imaging data is recorded using an X-ray detector;

[0049] The debugged grating phase contrast imaging system of the X-ray array target light source is obtained by debugging according to the above debugging method.

[0050] As a third aspect of the present invention, a grating phase contrast imaging system based on an X-ray array target light source is provided, which is used to implement the above-mentioned debugging method, and is characterized in that the system comprises:

[0051] An X-ray array target light source, a laser emitting mechanism, a beam splitting grating, an analyzing grating and an X-ray detector are sequentially arranged on the guide rail;

[0052] The target groove direction of the X-ray array target light source, the groove direction of the beam splitting grating and the groove direction of the analyzing grating are parallel.

[0053] According to an embodiment of the present invention, a laser emission mechanism is introduced for coarse adjustment, and the beam splitting grating and the analyzing grating lines are preferentially aligned to be parallel to each other. Then, based on the moiré pattern collected on the X-ray detector, the grating is always aligned with the target lines in the X-ray array target light source, and finally, the grating posture is precisely adjusted. This method utilizes the moiré pattern formed by the two gratings provided by the system and the target structure to cleverly determine the posture of the target structure within the light source. This debugging method is based on the internal optical elements of the grating phase contrast imaging system of the X-ray array target light source. With the help of only a laser emission mechanism that emits horizontal and vertical beams, the posture of the target structure within the light source can be determined. The operation is simple, and high-precision debugging of the system can be completed quickly, thereby improving both the adjustment efficiency and the adjustment accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0055] Figure 1 A flowchart of a debugging method for a grating phase contrast imaging system based on an X-ray array target light source according to an embodiment of the present invention is schematically shown;

[0056] Figure 2 A schematic diagram of a grating phase contrast imaging system based on an X-ray array target light source according to an embodiment of the present invention is shown schematically;

[0057] Figure 3 A schematic diagram showing the optical path principle of a grating phase contrast imaging system based on an X-ray array target light source according to an embodiment of the present invention is shown;

[0058] Figure 4 Schematic diagram showing laser light and diffraction fringes when a single grating rotates around the Z axis according to an embodiment of the present invention;

[0059] Figure 5 Schematic diagram showing laser light and diffraction fringes when a single grating rotates around the Y-axis according to an embodiment of the present invention;

[0060] Figure 6 Schematic diagram showing laser light and diffraction fringes when a single optical grating rotates around the X-axis according to an embodiment of the present invention;

[0061] Figure 7 A schematic diagram of moiré patterns when dual gratings rotate simultaneously around the Y axis according to an embodiment of the present invention is shown;

[0062] Figure 8 A schematic diagram of moiré patterns when dual gratings rotate simultaneously around the X-axis according to an embodiment of the present invention is shown;

[0063] Figure 9The diagram schematically shows a moiré pattern when the double gratings rotate simultaneously around the Z axis according to an embodiment of the present invention. DETAILED DESCRIPTION

[0064] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0065] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0066] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0067] When expressions such as "at least one of A, B and C, etc." are used, they should generally be interpreted in accordance with the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0068] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0069] In order to enhance the practicality of the traditional three-grating X-ray phase contrast imaging system, the X-ray array target light source was introduced into the Talbot-Lau grating interferometer, that is, the conventional X-ray source and the source grating G0 were integrated into one, thereby eliminating the large aspect ratio G0 grating, effectively improving the photon utilization efficiency and imaging field of view, and further promoting the practical application of X-ray grating phase contrast imaging.

[0070] In X-ray grating phase-contrast imaging systems, the grating's posture is closely related to imaging performance, making it particularly important to adjust the posture of each grating. In phase-contrast imaging systems using an X-ray array target light source, the target structure is located within the X-ray source, making it impossible to determine the precise posture of the target's scribed lines. Furthermore, once the optical axis is determined, the light source is typically not adjusted, significantly increasing the difficulty of aligning the two gratings so that their scribed lines are parallel to the X-ray array target structure.

[0071] Based on this, this scheme proposes a method of using a laser emission mechanism for rough adjustment, and according to the moiré pattern collected by the X-ray detector, linking the dual grating to control the groove structure of the dual grating to be always parallel to the groove direction of the target structure, and finally determining the precise posture of the target line.

[0072] Figure 1 The flowchart of the debugging method of the grating phase contrast imaging system based on the X-ray array target light source according to an embodiment of the present invention is schematically shown.

[0073] like Figure 1 As shown, the grating phase contrast imaging system includes a guide rail and an X-ray array target light source, a beam splitter grating (i.e., G1 beam splitter grating), an analyzer grating (i.e., G2 analyzer grating), and an X-ray detector sequentially arranged on the guide rail. The debugging method may include steps S110 to S180.

[0074] In operation S110, the laser emitting mechanism is placed on the guide rail, and the laser emits a vertical beam and a horizontal beam. The propagation directions of the vertical beam and the horizontal beam are the same, the vertical beam is distributed along the vertical direction, and the horizontal beam is distributed along the horizontal direction. The intersection of the vertical beam and the horizontal beam is the straight line where the optical axis is located, and the extension direction of the guide rail is parallel to the optical axis.

[0075] In operation S120 , an X-ray array target light source and an X-ray detector are placed on the guide rail, and a center of a light outlet of the X-ray array target light source is aligned with a target position of a receiving plane of the X-ray detector.

[0076] According to an embodiment of the present invention, operation S120 may include the following steps:

[0077] Install the X-ray array target light source and the X-ray detector on the guide rails respectively;

[0078] By using a laser emitting mechanism that emits horizontal and vertical beams, the light outlet of the X-ray array target light source and the center of the X-ray detector receiving plane are adjusted in the vertical direction to be at the same horizontal height.

[0079] In operation S130, the postures of the X-ray array target light source and the X-ray detector are adjusted to align the center of the spot formed by the X-rays emitted by the X-ray array target light source with the target position of the X-ray detector, and the optical axis coincides with the trajectory of the X-rays.

[0080] According to an embodiment of the present invention, the X-ray array target light source and the X-ray detector are turned on, and a light spot formed by X-rays emitted from the X-ray array target light source is observed through the X-ray detector. Operation S130 may include the following steps:

[0081] S21: adjusting the azimuth angle and height of the X-ray array target light source relative to the X-ray detector so that the center of the light spot coincides with the target position of the X-ray detector; wherein the target position is preferably the center position of the X-ray detector;

[0082] S22: moving the X-ray detector and the X-ray array target light source relative to each other along the guide rail, and then adjusting the azimuth angle and height of the X-ray array target light source relative to the X-ray detector so that the center of the light spot coincides with the target position of the X-ray detector;

[0083] S23: Repeat step S22 until the center of the light spot always coincides with the target position of the X-ray detector. In other words, when the X-ray array target light source and the X-ray detector move relative to each other on the guide rail, the center of the light spot always coincides with the center of the detector, and the adjustment is completed.

[0084] In operation S140, the analyzer grating is placed on the guide rail and the analyzer grating is adjusted so that the intersection line of the vertical light beam and the horizontal light beam passes through the center of the first diffraction fringe, wherein the first diffraction fringe is generated by the horizontal light beam and the vertical light beam irradiating the analyzer grating.

[0085] According to an embodiment of the present invention, the center of the laser emitting mechanism is the intersection of the extension lines of the horizontal light beam and the vertical light beam.

[0086] A laser emitting mechanism that emits horizontal and vertical beams (for example, a laser level) can be placed between the X-ray detector and the X-ray array target light source, so that the vertical and horizontal beams it emits pass through the target position of the X-ray detector at the same time, and the vertical beam is parallel to the guide rail; or two laser emitting mechanisms that emit horizontal and vertical beams can be used and placed on the optical axis outside the distance defined by the X-ray detector and the X-ray array target light source, so that the two laser emitting mechanisms that emit horizontal and vertical beams respectively locate the horizontal position and vertical height of the optical axis.

[0087] According to an embodiment of the present invention, when the laser emitting mechanism irradiates the grating, diffraction occurs, and multiple diffraction fringes are observed, wherein the 0-level bright fringes and the ±1-level bright fringes are the brightest. Operation S140 may include the following steps:

[0088] S31: placing the analyzer grating on the guide rail, and adjusting the analyzer grating in the vertical direction and the horizontal direction respectively so that the optical axis passes through the target area of ​​the analyzer grating;

[0089] S32: rotating the analyzer grating around the Z axis so that the first diffraction fringe remains horizontal; wherein the Z axis represents the direction of the optical axis;

[0090] S33: rotating the analyzer grating about the Y-axis so that the vertical center line of the first diffraction fringe coincides with the vertical light beam; wherein the Y-axis represents the vertical direction;

[0091] S34: rotating the analyzer grating about the X-axis so that the horizontal center line of the first diffraction fringe coincides with the horizontal light beam; wherein the X-axis represents the horizontal direction;

[0092] S35: Repeat steps S32 to S34 until the intersection of the vertical light beam and the horizontal light beam always passes through the center of the first diffraction fringe when the analyzer grating moves on the guide rail, and the adjustment is completed.

[0093] In operation S150, a beam splitting grating is placed on a guide rail and the beam splitting grating is adjusted so that the intersection line of the vertical light beam and the horizontal light beam passes through the center of the second diffraction fringe, wherein the second diffraction fringe is generated by the horizontal light beam and the vertical light beam irradiating the beam splitting grating.

[0094] According to an embodiment of the present invention, operation S150 may include the following steps:

[0095] S41: placing the beam splitting grating on the guide rail, and adjusting the beam splitting grating in the vertical direction and the horizontal direction respectively so that the optical axis passes through the target area of ​​the beam splitting grating;

[0096] S42: rotating the beam splitting grating around the Z axis so that the second diffraction fringe remains horizontal; wherein the Z axis represents the direction of the optical axis;

[0097] S43: rotating the beam splitting grating about the Y axis so that the vertical center line of the second diffraction fringe coincides with the vertical light beam; wherein the Y axis represents the vertical direction;

[0098] S44: rotating the beam splitting grating about the X-axis so that the horizontal center line of the second diffraction fringe coincides with the horizontal light beam; wherein the X-axis represents the horizontal direction;

[0099] S45: Repeat steps S42 to S44 until the intersection of the vertical light beam and the horizontal light beam always passes through the center of the second diffraction fringe when the beam splitting grating moves on the guide rail, that is, the adjustment is completed, and then the laser emitting mechanism is moved out of the guide rail.

[0100] In operation S160, the relative positions of the X-ray array target light source, the beam splitter grating, the analyzer grating and the X-ray detector are adjusted so that a moiré pattern can be observed on the X-ray detector. The moiré pattern is formed after the X-rays pass through the beam splitter grating and the analyzer grating.

[0101] According to an embodiment of the present invention, operation S160 may include the following steps:

[0102] Move the beam splitter grating along the optical axis so that the distance R between the center of the beam splitter grating and the target structure of the X-ray array target light source is 12.3 cm;

[0103] Move the analyzer grating along the optical axis so that the distance d between the center of the analyzer grating and the center of the G1 beam-splitting grating is 67.9 cm;

[0104] The X-ray detector is moved along the optical axis so that the X-ray detector is close to the analyzer grating, so that a moiré pattern formed by the beam splitting grating and the analyzer grating can be observed on the X-ray detector.

[0105] According to an embodiment of the present invention, R and d are calculated as follows.

[0106] According to the system design, the Talbot order N is preset to 1, the beam splitting grating is a π phase grating, the ratio of the beam splitting grating period to the self-imaging period η is 2, the wavelength of the irradiated light wave λ is 0.031 nm, the beam splitting grating period p1 is 5.08 μm, and the analyzer grating period p2 is 16.6 μm. The distance R between the center of the beam splitting grating and the target structure of the X-ray array target light source is calculated by formulas (1)-(2) to obtain 12.3 cm, and the distance d between the center of the beam splitting grating and the center of the analyzer grating is 67.9 cm. Formulas (1)-(2) are expressed as follows:

[0107]

[0108]

[0109] In operation S170, the beam splitter grating and the analyzer grating are synchronously rotated and adjusted, or the X-ray source is rotated and adjusted separately, so that the moiré pattern is parallel to the grating grooves of the beam splitter grating and the grating grooves of the analyzer grating, so as to ensure that the lines of the target structure in the X-ray array target light source are parallel to the lines of the beam splitter grating and the analyzer grating at the same time.

[0110] According to an embodiment of the present invention, operation S170 may include the following steps:

[0111] S61: Rotate the beam splitting grating and the analysis grating around the Y axis simultaneously, or rotate and adjust the X-ray source separately, so that the left and right periods of the moiré pattern observed on the X-ray detector are consistent; wherein, the consistency of the left and right periods means that the stripe widths of the moiré pattern are the same.

[0112] S62: rotating the beam splitter grating and the analyzer grating simultaneously around the X-axis, or rotating and adjusting the X-ray source separately, so that the upper and lower periods of the moiré pattern observed on the X-ray detector are consistent, thereby obtaining a moiré pattern with a periodic arrangement;

[0113] S63: Rotate the beam splitter grating and the analyzer grating simultaneously around the Z axis, or rotate and adjust the X-ray source separately, so that the moiré pattern observed on the X-ray detector is parallel to the grating groove direction of the beam splitter grating and the analyzer grating;

[0114] S64: Repeat steps S61 to S63 so that the moiré pattern observed on the X-ray detector is always parallel to the direction of the grating grooves of the beam splitter grating and the direction of the grating grooves of the analyzer grating, that is, the lines of the target structure in the X-ray array target light source are parallel to the lines of the beam splitter grating and the lines of the analyzer grating.

[0115] In operation S180, the beam splitter grating and the analyzer grating are individually adjusted to maximize the visibility of the moiré pattern, and then the beam splitter grating is moved along the optical axis to obtain a substantially uniformly distributed light field on the X-ray detector, thereby completing the optical path debugging.

[0116] According to an embodiment of the present invention, operation S180 may include the following steps:

[0117] S71: Adjust the beam splitter grating individually to rotate around the X-axis, the Y-axis, and the Z-axis to achieve the highest visibility of the moiré pattern and fix it in this position;

[0118] S72: The analyzer grating is individually adjusted to rotate around the X axis, the Y axis, and the Z axis so that the moiré pattern is most visible, and fixed at this position;

[0119] S73: Moving the beam splitting grating along the optical axis to obtain a roughly evenly distributed light field on the X-ray detector, thereby completing the optical path debugging.

[0120] According to an embodiment of the present invention, a laser emission mechanism is introduced, and the beam splitting grating and the analyzing grating lines are preferentially aligned parallel to each other. Then, based on the moiré pattern captured on the X-ray detector, the grating is maintained parallel to the target lines in the X-ray array target light source, and finally, the grating posture is precisely adjusted. This method utilizes the moiré pattern formed by the two gratings provided by the system and the target structure to cleverly determine the posture of the target structure within the light source. This debugging method is based on the internal optical elements of the grating interferometer system and can determine the posture of the target structure within the light source with the help of only a laser emission mechanism. It is simple to operate and can quickly complete high-precision debugging of the system, thereby improving both the adjustment efficiency and the adjustment accuracy.

[0121] According to an embodiment of the present invention, a sample to be tested is placed at a designated sample position in a grating phase contrast imaging system of a debugged X-ray array target light source, and imaging data thereof is recorded using an X-ray detector;

[0122] The debugged grating phase contrast imaging system of the X-ray array target light source is obtained by debugging according to any one of the above debugging methods.

[0123] Figure 2 A schematic diagram of a grating phase contrast imaging system based on an X-ray array target light source according to an embodiment of the present invention is shown schematically.

[0124] like Figure 2 As shown, the grating phase contrast imaging system includes an X-ray array target light source, a laser emitting mechanism, a G1 beam splitting grating, a G2 analyzer grating and an X-ray detector in sequence along the optical axis direction, wherein each component has a corresponding adjustment component, which is not marked in the figure.

[0125] According to an embodiment of the present invention, the target groove direction of the X-ray array target light source, the groove direction of the G1 beam splitting grating, and the groove direction of the G2 analyzer grating are the same; the target structure of the X-ray array target light source, the G1 beam splitting grating, and the period of the G2 analyzer grating can be the same or different, depending on the actual system design.

[0126] According to an embodiment of the present invention, the X-ray array target light source, the G1 beam splitting grating and the G2 analysis grating can be one-dimensional gratings or two-dimensional gratings, etc., which also depends on the actual system design; the wavelength of the laser emitting mechanism also depends on the actual system design. Preferably, when the first-order Talbot order is adopted, the wavelength of the laser emitting mechanism can be, for example, 515 nm.

[0127] According to an embodiment of the present invention, with a system energy of 40 keV and a first-order Talbot order, the target structure, G1 beamsplitter grating, and G2 analyzer grating periods of 3 μm, 5.08 μm, and 16.6 μm, respectively, are obtained, with a total system length of 80.2 cm. Depending on the Talbot order employed, different target structures, G1 beamsplitter grating, and G2 analyzer grating periods can be achieved. This debugging method is applicable to grating phase contrast imaging systems constructed with different Talbot orders.

[0128] Figure 3 The optical path principle diagram of the grating phase contrast imaging system based on the X-ray array target light source according to an embodiment of the present invention is schematically shown.

[0129] like Figure 3As shown, turning on the X-ray array target light source and X-ray detector reveals a light spot emitted by the X-ray array target light source, which then passes through the X-ray array target light source, the G1 beam splitter grating, and the G2 analyzer grating before arriving at the X-ray detector. By introducing a laser emission mechanism to debug the optical path, and based on the moiré pattern captured by the X-ray detector, the dual gratings are linked to maintain their grooves parallel to the grooves of the target structure, ultimately determining the precise orientation of the target's scribed lines.

[0130] Figure 4 The figure schematically shows the laser and diffraction fringes when a single grating rotates around the Z axis according to an embodiment of the present invention.

[0131] like Figure 4 As shown, by adjusting the rotation of a single grating around the Z axis (i.e., the optical axis), the laser beam and the diffraction fringe can be observed on the wall in a step-like manner. Figure 4 Figure (a) shows the off-axis case 1 that occurs when a single grating is rotated counterclockwise around the Z axis (i.e., the optical axis). In this case, there is a negative tilt angle between the -1st order diffraction fringe and the +1st order diffraction fringe. Figure 4 Figure (b) shows the coaxial situation that occurs when a single grating is rotated around the Z axis (i.e., the optical axis) and along the optical axis. In this case, all diffraction fringes remain horizontal. Figure 4 Figure (c) shows the off-axis situation 2 that occurs when a single grating is rotated clockwise around the Z axis (i.e., the optical axis). At this time, there is a positive tilt angle between the -1 order diffraction fringe and the +1 order diffraction fringe. It should be noted that the positive and negative tilt angles can be equal or unequal; this is not limited here and is related to the actual diffraction fringe pattern.

[0132] Figure 5 The figure schematically shows the laser and diffraction stripes when a single grating rotates around the Y-axis according to an embodiment of the present invention.

[0133] Figure 5 The single grating in is an analyzer grating or a beam splitter grating, such as Figure 5 As shown, by adjusting the rotation of a single grating around the Y axis, the diffraction fringe can be observed on the vertical wall surface to translate along the horizontal direction (ie, the X axis). Figure 5 Figure (a) shows the off-axis case 1 that occurs when a single grating is rotated counterclockwise about the Y-axis. In this case, the -1-order diffraction fringe and the +1-order diffraction fringe are asymmetric with respect to the laser beam, and the 0-order diffraction fringe is also asymmetric with respect to the laser beam. More specifically, the distance between the -1-order diffraction fringe and the laser beam is greater than the distance between the +1-order diffraction fringe and the laser beam. Figure 5Figure (b) shows the coaxial situation that occurs when a single grating is rotated around the Y-axis. In this case, the 0th-order diffraction fringe coincides with the center of the laser emitting mechanism. That is, all diffraction fringes remain horizontal, the -1st-order diffraction fringe and the +1st-order diffraction fringe are symmetrical about the laser beam, and the 0th-order fringe is symmetrical about the laser beam center. Figure 5 Figure (c) shows the off-axis case 2 that occurs when a single grating is rotated clockwise around the Y-axis. In this case, the -1-order diffraction fringe and the +1-order diffraction fringe are asymmetric with respect to the laser beam, and the 0-order fringe is also asymmetric with respect to the laser beam. More specifically, the distance between the -1-order diffraction fringe and the laser beam is smaller than the distance between the +1-order diffraction fringe and the laser beam. It should be noted that the distances in off-axis case 1 and off-axis case 2 can be equal or unequal; this is not limited here and is related to the actual diffraction fringe pattern.

[0134] Figure 6 The figure schematically shows the laser and diffraction fringes when the single optical grating rotates around the X-axis according to an embodiment of the present invention.

[0135] Figure 6 The single grating in is an analyzer grating or a beam splitter grating. Figure 6 As shown, by adjusting a single grating to rotate around the X-axis, diffraction fringes can be observed on a vertical wall to translate along the vertical direction (i.e., the Y-axis). All diffraction fringes remain horizontal, and the -1st and +1st order diffraction fringes are symmetrical about the laser beam, and the 0th order fringes are symmetrical about the center of the laser beam. Specifically, Figure 6 Figure (a) shows the off-axis case 1 that occurs when a single grating is rotated counterclockwise around the X-axis. In this case, the diffraction fringe is vertically higher than the center of the horizontal light of the laser emitting mechanism; Figure 6 Figure (b) shows the coaxial situation that occurs when a single grating is rotated around the X-axis and along the X-axis. In this case, the horizontal center of the diffraction fringe coincides with the center of the horizontal light of the laser emission mechanism. Figure 6 Figure (c) shows the off-axis case 2 that occurs when a single grating is rotated clockwise around the X-axis. In this case, the diffraction fringe is lower than the center of the horizontal light of the laser emitting mechanism in the vertical direction. It should be noted that the distance between the diffraction fringe in off-axis cases 1 and 2 and the center of the horizontal light of the laser emitting mechanism can be equal or unequal; this is not limited here and is related to the actual diffraction fringe pattern.

[0136] Figure 7 The diagram schematically shows a moiré pattern when the double gratings rotate simultaneously around the Y axis according to an embodiment of the present invention.

[0137] like Figure 7 As shown, Figure 7 Figure (a) shows the off-axis situation 1 that occurs when the double gratings are rotated counterclockwise around the Y axis at the same time. Figure 7 Figure (b) shows the coaxial situation that occurs when the double gratings are simultaneously rotated around the Y axis and along the Y axis. Figure 7 Figure (c) shows the off-axis condition 2 that occurs when the dual gratings are rotated clockwise around the Y-axis. By simultaneously adjusting the G1 beamsplitting grating and the G2 analyzer grating around the Y-axis, the left-right period of the moiré pattern observed on the X-ray detector is inconsistent. The coaxial condition corresponds to a consistent left-right period of the moiré pattern.

[0138] Figure 8 The diagram schematically shows the moiré pattern when the double gratings rotate around the X-axis simultaneously according to an embodiment of the present invention.

[0139] Figure 8 The double gratings in the figure are the G1 beam splitter grating and the G2 analyzer grating. Figure 8 As shown, when the G1 beam splitter grating and the G2 analyzer grating are adjusted to rotate around the X-axis, the upper and lower periods of the moiré pattern can be observed to be inconsistent on the X-ray detector. Specifically, Figure 8 Figure (a) shows the off-axis case 1 that occurs when the dual gratings are rotated counterclockwise around the X-axis simultaneously. In this case, the moiré pattern appears as an inverted trapezoid. Figure 8 Figure (b) shows the coaxial situation that occurs when the two gratings are simultaneously rotated around the X-axis and along the X-axis direction. The coaxial situation corresponds to the consistency of the upper and lower periods of the moiré pattern; Figure 8 Figure (c) shows the off-axis situation 2 that occurs when the dual gratings are simultaneously rotated clockwise around the X-axis. In this case, the moiré pattern appears as a positive trapezoid. It should be noted that the positive and negative inclination angles of the positive trapezoid and the inverted trapezoid can be the same or different, depending on the actual moiré pattern.

[0140] Figure 9 The diagram schematically shows a moiré pattern when the double gratings rotate simultaneously around the Z axis according to an embodiment of the present invention.

[0141] like Figure 9 As shown, when the G1 beam splitter grating and the G2 analyzer grating are simultaneously adjusted to rotate around the Z axis, a tilted moiré pattern can be observed on the X-ray detector relative to the vertical grooves of the dual gratings. Specifically, Figure 9 Figure (a) shows the off-axis case 1 that occurs when the dual gratings are rotated counterclockwise around the Z axis simultaneously. In this case, the moiré pattern has a positive tilt angle. Figure 9 Figure (b) shows the coaxial situation that occurs when the dual gratings are simultaneously rotated around the Z axis and along the Z axis. The coaxial situation corresponds to the moiré pattern being parallel to the groove direction of the dual gratings. Figure 9Figure (c) shows the off-axis situation 2 that occurs when the dual gratings are simultaneously rotated clockwise around the Z axis. In this case, the moiré pattern has a negative tilt angle. It should be noted that the positive and negative tilt angles here can be the same or different, depending on the actual moiré pattern.

[0142] It should be noted that this solution does not limit the rotation angle of the single grating and the double grating, and the specific adjustment is determined according to the diffraction fringe pattern and the moiré pattern.

[0143] According to an embodiment of the present invention, this scheme aims to repeatedly adjust the corresponding components based on the moiré pattern collected by the X-ray detector, so that the target groove direction of the X-ray array target light source is ultimately always parallel to the groove directions of the G1 beam splitter grating and the G2 analyzer grating. This debugging method is simple to operate, easy to adjust, and requires few adjustment components, so that high-precision debugging of the system can be completed quickly.

[0144] According to an embodiment of the present invention, a method for testing a grating phase contrast imaging system based on an X-ray array target light source is also provided, comprising:

[0145] The sample to be tested is placed at the designated sample position in the grating phase contrast imaging system of the debugged X-ray array target light source, and the imaging data is recorded using an X-ray detector;

[0146] The debugged grating phase contrast imaging system of the X-ray array target light source is obtained by debugging according to the above debugging method.

[0147] According to an embodiment of the present invention, a grating phase contrast imaging system based on an X-ray array target light source is further provided, which is used to implement the above method. The system includes:

[0148] An X-ray array target light source, a laser emitting mechanism, a beam splitting grating, an analyzing grating and an X-ray detector are sequentially arranged on the guide rail;

[0149] The target groove direction of the X-ray array target light source, the groove direction of the beam splitting grating and the groove direction of the analyzing grating are parallel.

[0150] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A debugging method for a grating phase contrast imaging system based on an X-ray array target light source, the grating phase contrast imaging system comprising a guide rail and an X-ray array target light source, a beam splitter grating, an analyzer grating, and an X-ray detector sequentially arranged on the guide rail, the debugging method comprising: Placing a laser emitting mechanism on the guide rail, and causing the laser emitting mechanism to emit a vertical beam and a horizontal beam, wherein the vertical beam and the horizontal beam have the same propagation direction, the vertical beam is distributed along the vertical direction, and the horizontal beam is distributed along the horizontal direction, the intersection of the vertical beam and the horizontal beam is the straight line where the optical axis is located, and the extension direction of the guide rail is parallel to the optical axis; Placing the X-ray array target light source and the X-ray detector on the guide rail, and aligning the center of the light outlet of the X-ray array target light source with the target position of the X-ray detector receiving plane; Adjusting the postures of the X-ray array target light source and the X-ray detector to align the center of the spot formed by the X-rays emitted by the X-ray array target light source with the target position of the X-ray detector, wherein the optical axis coincides with the trajectory of the X-rays; Placing the analyzer grating on the guide rail and adjusting the analyzer grating so that the intersection of the vertical light beam and the horizontal light beam passes through the center of a first diffraction fringe, wherein the first diffraction fringe is generated by the horizontal light beam and the vertical light beam irradiating the analyzer grating; Placing the beam splitting grating on the guide rail and adjusting the beam splitting grating so that the intersection of the vertical light beam and the horizontal light beam passes through the center of a second diffraction fringe, wherein the second diffraction fringe is generated by the horizontal light beam and the vertical light beam irradiating the beam splitting grating; adjusting the relative positions of the X-ray array target light source, the beam splitter grating, the analyzer grating, and the X-ray detector so that a moiré pattern can be observed on the X-ray detector, the moiré pattern being formed after the X-rays pass through the beam splitter grating and the analyzer grating; synchronously rotating and adjusting the beam splitter grating and the analyzer grating, or rotating and adjusting the X-ray source separately, so that the moiré pattern is parallel to the grating groove direction of the beam splitter grating and the grating groove direction of the analyzer grating, thereby ensuring that the scribed lines of the target structure in the X-ray array target light source are parallel to the scribed lines of the beam splitter grating and the scribed lines of the analyzer grating; The beam splitting grating and the analyzing grating are individually adjusted to maximize the visibility of the moiré pattern, and then the beam splitting grating is moved along the optical axis to obtain a roughly uniformly distributed light field on the X-ray detector, thereby completing the optical path debugging.

2. The debugging method according to claim 1, characterized in that: Adjusting the postures of the X-ray array target light source and the X-ray detector to align the center of the spot formed by the X-rays with the target position of the X-ray detector includes the following steps: S21: adjusting the azimuth angle and height of the X-ray array target light source relative to the X-ray detector so that the center of the light spot coincides with the target position of the X-ray detector; S22: moving the X-ray detector and the X-ray array target light source relative to each other along the guide rail, and then adjusting the azimuth angle and height of the X-ray array target light source relative to the X-ray detector so that the center of the light spot coincides with the target position of the X-ray detector; S23: Repeat step S22 until the center of the light spot always coincides with the target position of the X-ray detector.

3. The debugging method according to claim 1, wherein: Placing the analyzer grating on the guide rail and adjusting the analyzer grating so that the intersection line of the vertical light beam and the horizontal light beam passes through the center of the first diffraction fringe, comprising the following steps: S31: placing the analyzer grating on the guide rail, and adjusting the analyzer grating in the vertical direction and the horizontal direction respectively so that the optical axis passes through the target area of ​​the analyzer grating; S32: Rotate the analyzer grating around the Z axis so that the first diffraction fringe remains horizontal; wherein the Z axis represents the direction of the optical axis; S33: rotating the analyzer grating around the Y-axis so that the vertical center line of the first diffraction fringe coincides with the vertical light beam; wherein the Y-axis represents the vertical direction; S34: rotating the analyzer grating around the X-axis so that the horizontal center line of the first diffraction fringe coincides with the horizontal light beam; wherein the X-axis represents the horizontal direction; S35: Repeat steps S32 to S34 until the intersection of the vertical light beam and the horizontal light beam always passes through the center of the first diffraction fringe when the analyzer grating moves on the guide rail.

4. The debugging method according to claim 1, wherein: Placing the beam splitting grating on the guide rail and adjusting the beam splitting grating so that the intersection line of the vertical light beam and the horizontal light beam passes through the center of the second diffraction fringe, comprising the following steps: S41: placing the beam splitting grating on the guide rail, and adjusting the beam splitting grating in the vertical direction and the horizontal direction respectively so that the optical axis passes through the target area of ​​the beam splitting grating; S42: Rotate the beam splitting grating around the Z axis so that the second diffraction fringe remains horizontal; wherein the Z axis represents the direction of the optical axis; S43: rotating the beam splitting grating around the Y-axis so that the vertical center line of the second diffraction fringe coincides with the vertical light beam; wherein the Y-axis represents the vertical direction; S44: rotating the beam splitting grating around the X-axis so that the horizontal center line of the second diffraction fringe coincides with the horizontal light beam; wherein the X-axis represents the horizontal direction; S45: Repeat steps S42 to S44 until the intersection of the vertical light beam and the horizontal light beam always passes through the center of the second diffraction fringe when the beam splitting grating moves on the guide rail and moves out of the laser emitting mechanism.

5. The debugging method according to claim 1, wherein: The adjusting the relative positions of the X-ray array target light source, the beam splitting grating, the analyzer grating, and the X-ray detector so that a moiré pattern can be observed on the X-ray detector includes: Moving the beam splitting grating along the optical axis so that the distance between the center of the beam splitting grating and the target structure of the X-ray array target light source is R; Moving the analyzer grating along the optical axis so that the distance between the center of the analyzer grating and the center of the beam splitting grating is d; The X-ray detector is moved along the optical axis and brought close to the analyzer grating, so that a moiré pattern formed by the beam splitting grating and the analyzer grating can be observed on the X-ray detector.

6. The debugging method according to claim 1, wherein: The synchronous rotation adjustment of the beam splitter grating and the analyzer grating, or the independent rotation adjustment of the X-ray source, so that the moiré pattern is parallel to the grating grooves of the beam splitter grating and the grating grooves of the analyzer grating, thereby ensuring that the scribed lines of the target structure in the X-ray array target light source are simultaneously parallel to the scribed lines of the beam splitter grating and the scribed lines of the analyzer grating, comprises the following steps: S61: rotating the beam splitting grating and the analyzer grating simultaneously around the Y axis, or rotating and adjusting the X-ray source separately, so that the left and right periods of the moiré pattern observed on the X-ray detector are consistent; S62: rotating the beam splitting grating and the analyzer grating simultaneously around the X-axis, or rotating and adjusting the X-ray source alone, so that the upper and lower periods of the moiré pattern observed on the X-ray detector are consistent; S63: rotating the beam splitter grating and the analyzer grating simultaneously around the Z axis, or rotating and adjusting the X-ray source separately, so that the moiré pattern observed on the X-ray detector is parallel to the grating groove directions of the beam splitter grating and the analyzer grating; S64: Repeat steps S61 to S63 so that the moiré pattern observed on the X-ray detector is always parallel to the grating groove direction of the beam splitter grating and the grating groove direction of the analyzer grating, that is, the grating lines of the target structure in the X-ray array target light source are parallel to the grating lines of the beam splitter grating and the grating lines of the analyzer grating.

7. The debugging method according to claim 1, characterized in that: The step of individually adjusting the beam splitting grating and the analyzer grating to maximize the visibility of the moiré pattern, and then moving the beam splitting grating along the optical axis to obtain a substantially uniformly distributed light field on the X-ray detector, thereby completing the optical path debugging, includes the following steps: S71: individually adjusting the beam splitting grating to rotate around the X axis, around the Y axis, and around the Z axis so that the moiré pattern is most visible, and fixing it at this position; S72: individually adjusting the analyzer grating to rotate around the X axis, around the Y axis, and around the Z axis so that the moiré pattern is most visible, and fixing it at this position; S73: Moving the beam splitting grating along the optical axis to obtain a substantially uniformly distributed light field on the X-ray detector, thereby completing optical path debugging.

8. The debugging method according to claim 1, wherein: The step of aligning the center of the light outlet of the X-ray array target light source with the target position of the receiving plane of the X-ray detector comprises: Installing the X-ray array target light source and the X-ray detector on the guide rail respectively; The laser emission mechanism is used to adjust the light outlet center of the X-ray array target light source and the target position of the X-ray detector receiving plane to the same level along the vertical direction.

9. A method for testing a grating phase contrast imaging system based on an X-ray array target light source, comprising: The sample to be tested is placed at a designated sample position in the grating phase contrast imaging system of the debugged X-ray array target light source, and the imaging data thereof is recorded using the X-ray detector; The debugged grating phase contrast imaging system of the X-ray array target light source is obtained by debugging the system according to any one of claims 1 to 8.

10. A grating phase contrast imaging system based on an X-ray array target light source, used to implement the method according to any one of claims 1 to 8, characterized in that: The system includes: An X-ray array target light source, a beam splitter grating, an analyzer grating and an X-ray detector are sequentially arranged on the guide rail; The target groove direction of the X-ray array target light source, the groove direction of the beam splitting grating, and the groove direction of the analyzer grating are parallel.

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