Method for adjusting light beam based on half-slit diaphragm and X-ray radiation device

Abstract

The invention provides a method for adjusting a light beam based on a half-slit diaphragm and an X-ray radiation device, and the method comprises the steps: building the X-ray radiation device when responding to bremsstrahlung radiation parameters of an X-ray machine meet requirements; the method for adjusting the pose of the collimator to a target pose comprises the following steps of: obtaining the number of first photons of an emergent beam of an X-ray machine detected by the detector within a preset time when the diaphragm is placed between the collimator and the detector; the diaphragm is taken out, and a half-slit diaphragm is placed in situ; driving the half-slit diaphragm to move, and acquiring the number of second photons of the emergent beam detected when an outlet of the half-slit diaphragm is located at different positions through the detector within a preset time; and adjusting the pose of the collimator tube according to the number of the second photons and the number of the first photons when the outlet of the half-slit diaphragm is located at different positions. By adopting the technical scheme, the peak value and the output stability of the X-ray can be improved.

Description

Technical Field

[0001] This application relates to the field of single-crystal X-ray diffraction technology, and in particular to a method for adjusting the beam based on a semi-slit aperture and an X-ray radiation device. Background Technology

[0002] Monochromatic X-rays refer to X-rays containing only a single wavelength or energy, also known as monoenergetic X-rays. Monochromatic X-rays have a single energy level and low background noise, making them primarily used for high-precision analysis and possessing significant application value in multiple fields.

[0003] Existing methods for generating monochromatic X-rays have several problems. For example, radioactive isotope sources have a narrow energy range, cannot be adjusted in energy, and pose radioactive hazards. K-fluorescence, as one of the traditional methods, generates characteristic X-rays by exciting a specific target material, but it also suffers from the problem of a single energy point.

[0004] X-ray free-electron lasers and synchrotron radiation facilities have superior performance, but their large equipment size and high operating costs make them difficult to popularize.

[0005] Monochromatic X-rays generated by X-ray machines and the Bragg diffraction principle offer continuously adjustable energy, low cost, and ease of operation, making them a cost-effective option for detector calibration. There are two methods for generating monochromatic X-rays using X-ray machines and the Bragg diffraction principle: single-crystal and dual-crystal. Dual-crystal radiation devices offer continuously adjustable energy, good monochromaticity, and high stability, but suffer from difficulties in device adjustment and a limited energy range. Single-crystal devices have a simple structure, but the X-ray tube is small, the energy is low, the collimator alignment accuracy depends on manual adjustment, the X-ray utilization rate is low, and monochromaticity optimization is difficult. Summary of the Invention

[0006] In view of this, this application provides a method for adjusting the beam based on a semi-slit aperture and an X-ray radiation device, which can improve the peak value and output stability of X-rays.

[0007] In a first aspect, this application provides a method for adjusting a light beam based on a half-slit aperture, comprising:

[0008] When the bremsstrahlung parameters of the X-ray machine meet the requirements, an X-ray radiation device is set up. The X-ray radiation device includes an X-ray machine, a single crystal, a collimator, an aperture, and a detector, which are placed sequentially along the optical path.

[0009] Adjusting the pose of the collimator to a target pose includes: acquiring the number of first photons of the X-ray machine's output beam detected by the detector within a preset time when the aperture is placed between the collimator and the detector; removing the aperture and placing a semi-slit aperture in its original position; driving the semi-slit aperture to move, and acquiring the number of second photons of the output beam detected by the detector when the exit of the semi-slit aperture is located at different positions within the preset time; and adjusting the pose of the collimator based on the number of second photons when the exit of the semi-slit aperture is located at different positions and the number of first photons.

[0010] Optionally, adjusting the pose of the collimator based on the number of second photons when the exit of the semi-slit aperture is at different positions, and the number of first photons, includes:

[0011] Determine the difference in the number of second photons when the exit of the semi-slit aperture is located at different positions;

[0012] When the difference is less than a preset difference, the pose of the collimator in the optical path is fixed; the preset difference is determined based on the first photon count.

[0013] When the difference is not less than a preset difference, the collimator is adjusted according to the position of the exit corresponding to the larger number of second photons, so that the collimator moves toward the position indicated by the larger number of second photons until the difference is less than the preset difference.

[0014] Optionally, after adjusting the pose of the collimator, a verification operation is also included;

[0015] The verification operation includes: removing the semi-slit aperture and placing it in its original position, and obtaining the first photon count again; removing the aperture and placing it in its original position, and obtaining the second photon count when the exit of the semi-slit aperture is located at different positions; and fixing the pose of the collimator when the difference is less than the preset difference based on the second photon count when the exit of the semi-slit aperture is located at different positions.

[0016] Optionally, the method for adjusting the beam satisfies one or more of the following:

[0017] During the detection of the emitted beam, the photon count per unit time follows a Poisson distribution;

[0018] The preset difference is determined by using the light exit area of ​​the aperture and the light exit area of ​​the slit aperture to determine the photon count corresponding to the light exit of the slit aperture as λN; and by using 2 times the standard deviation corresponding to the Poisson distribution to determine the preset difference.

[0019] After fixing the position of the collimator, the process also involves removing the semi-slit aperture and placing it back in place.

[0020] The light exit area of ​​the aperture is 12.57 mm². 2 The preset time is 10 seconds, and the photon count is N.

[0021] The light exit area of ​​the semi-slit aperture is 7.5 mm². 2 The corresponding photon count is 0.6, with a standard deviation of 2.

[0022] Optionally, the process of setting up an X-ray radiation device in response to the requirement that the bremsstrahlung parameters of the X-ray machine meet the requirements includes:

[0023] The detector is placed on the second platform, and the X-ray machine is placed on the first platform;

[0024] The single crystal is placed between the X-ray machine and the detector, and the position of the main beam transmitted to the detector via the single crystal is determined.

[0025] A collimator is provided along the transmission path of the main beam, and the collimator is parallel to the transmission path of the main beam.

[0026] An aperture is provided on the side of the collimator near the detector to limit the main beam passing through the collimator;

[0027] A lead plate is placed between the aperture and the detector. The lead plate has a hole through which the main beam passes, and the position of the hole corresponds to that of the aperture.

[0028] Optionally, the bremsstrahlung parameters of the X-ray machine are obtained by the detector when a preset tube voltage and tube current are applied to the X-ray machine;

[0029] The step of placing the single crystal between the X-ray machine and the detector, and determining the position of the main beam transmitted to the detector via the single crystal, includes:

[0030] The rotation angle of the single crystal is determined according to Bragg's formula.

[0031] When the X-ray machine is driven to emit an outgoing beam, the second platform is driven to move in the first direction and the second direction, changing the incident position of the main beam irradiating the detector through the single crystal, and obtaining the number of photons corresponding to different incident positions;

[0032] The incident position with the highest number of photons is taken as the position of the main beam.

[0033] Optionally, the step of setting a collimator along the transmission path of the main beam, and making the collimator parallel to the transmission path of the main beam, includes:

[0034] A support frame is installed between the first platform and the second platform;

[0035] The collimator is placed on the support, and the horizontal and vertical directions of the two supports are initially adjusted by the laser instrument until the center of the collimator coincides with the center of the main beam.

[0036] Optionally, the method for adjusting the beam satisfies one or more of the following:

[0037] The X-ray machine emits monochromatic X-ray beams;

[0038] The single crystal is a Si555 crystal;

[0039] The detector is an HPGe detector.

[0040] Secondly, this application also provides an X-ray radiation device, comprising: an X-ray machine, a single crystal, a collimator, an aperture, and the detector arranged sequentially along the optical path;

[0041] The X-ray radiation device employs a beam adjustment method based on a semi-slit aperture as described in any of the preceding claims, adjusting the X-ray beam by adjusting the position of the collimator.

[0042] Optionally, the X-ray radiation device also includes:

[0043] A lead plate is disposed between the aperture and the detector, and the lead plate has a hole for the main beam to pass through, and the position of the hole corresponds to the aperture;

[0044] The first platform is used to support the X-ray machine;

[0045] The second platform is used to carry the detector;

[0046] A support, located between the first platform and the second platform, is used to support the collimation tube.

[0047] Compared with the prior art, the technical solution of this application has the following advantages:

[0048] In the method for adjusting the beam based on a semi-slit aperture provided in this application embodiment, in response to the bremsstrahlung parameters of the X-ray machine meeting the requirements, an X-ray radiation device is set up, and the pose of the collimator is adjusted based on the first photon count when the aperture is placed between the collimator and the detector, and the second photon count when the semi-slit aperture is placed between the collimator and the detector, so that the number of photons of the beam emitted from different directions through the collimator has higher uniformity, the collimator has higher alignment accuracy, and the radiation utilization rate is improved, thereby improving the peak value and output stability of X-rays. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0050] Figure 1 A flowchart of a method for adjusting a light beam based on a semi-slit aperture is shown in an embodiment of this application;

[0051] Figure 2 A flowchart illustrating the construction of an X-ray radiation device according to an embodiment of this application is shown;

[0052] Figures 3 to 6 This illustration shows a process for constructing an X-ray radiation device according to an embodiment of this application;

[0053] Figure 7 The first monochromatic X-ray energy spectrum in the embodiments of this application is shown;

[0054] Figure 8 The second monochromatic X-ray energy spectrum in an embodiment of this application is shown;

[0055] Figure 9 The third monochromatic X-ray energy spectrum in the embodiments of this application is shown;

[0056] Figure 10 The fourth monochromatic X-ray energy spectrum in the embodiments of this application is shown;

[0057] Figure 11 The fifth monochromatic X-ray energy spectrum in the embodiments of this application is shown;

[0058] Figure 12 A flowchart illustrating a specific process for adjusting a beam based on a semi-slit aperture in an embodiment of this application is shown.

[0059] Figure 13A comparison diagram of the X-ray energy spectrum before and after adjustment of a semi-slit aperture in an embodiment of this application is shown. Detailed Implementation

[0060] Various embodiments of the invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0061] As described in the background section, X-ray machines and the Bragg diffraction principle generate monochromatic X-rays in two ways: single-crystal and dual-crystal. However, both methods have limitations.

[0062] This application addresses the issue of single crystals by constructing a monochromatic X-ray radiation device based on single crystal diffraction. It proposes a method for dynamically adjusting the collimator using a semi-slit aperture, which improves the intensity and monochromaticity of monochromatic X-rays and increases the energy of the monochromatic X-ray radiation device to 150 keV.

[0063] Specifically, in response to the bremsstrahlung parameters of the X-ray machine meeting the requirements, an X-ray radiation device is constructed. Based on the number of first photons when the aperture is placed between the collimator and the detector, and the number of second photons when the semi-slit aperture is placed between the collimator and the detector, the pose of the collimator is adjusted so that the number of photons emitted from the collimator in different directions has higher uniformity, the collimator has higher alignment accuracy, and the radiation utilization rate is improved, thus improving the peak value and output stability of X-rays.

[0064] To enable those skilled in the art to better understand and implement this disclosure, the following detailed description of the specific solutions, principles, advantages, and effects of this application is provided with reference to the accompanying drawings and specific embodiments.

[0065] See Figures 1 to 6 , Figure 1 This is a flowchart illustrating a method for adjusting a light beam based on a semi-slit aperture in an embodiment of this application. Figure 2 This is a flowchart illustrating the construction of an X-ray radiation device according to an embodiment of this application; Figures 3 to 6 This is a schematic diagram illustrating the process of constructing an X-ray radiation device in an embodiment of this application.

[0066] See Figures 1 to 6 The following steps can be performed:

[0067] S11, In response to the bremsstrahlung parameters of the X-ray machine meeting the requirements, an X-ray radiation device is constructed, the X-ray radiation device including an X-ray machine, a single crystal, a collimator, an aperture, a lead plate, and a detector placed sequentially along the optical path.

[0068] In some embodiments, when setting up a monochromatic X-ray radiation device, it is necessary to measure the bremsstrahlung radiation generated by the X-ray machine beforehand to ensure that the target material of the X-ray machine matches the information provided by the manufacturer. This is crucial for improving the adjustment of X-rays.

[0069] In this embodiment, the detector can be aligned with the X-ray machine's output port to directly measure the initial X-ray beam and observe whether the energy spectrum contains tungsten's characteristic peak. During the measurement process, to ensure that the X-ray machine has sufficient kinetic energy to excite the K-shell electrons of tungsten atoms to produce a significant characteristic radiation peak, while preventing the photon count from becoming too high and causing the high-purity germanium detector to become clogged, the characteristic peak energy of tungsten is 59.25 keV. Therefore, the tube voltage of the X-ray machine is set to 90 kV, and the tube current is 0.5 mA.

[0070] Accordingly, such as Figure 7 The first monochromatic X-ray energy spectrum shown in the embodiments of this application is as follows: Figure 7 The bremsstrahlung energy spectrum shown is a typical continuous spectrum, with the K value at 59.25 keV corresponding to the tungsten target's K value. α Characteristic peaks.

[0071] Thus, the result verifies that the X-ray machine used generates bremsstrahlung using a tungsten target, which meets the requirements.

[0072] In this embodiment, the output beam of the X-ray machine is monochromatic X-ray. The X-ray machine is based on the principle of bremsstrahlung, generating X-rays by accelerating an electron beam to bombard an anode target, which then undergoes Bragg diffraction by a crystal to obtain monochromatic X-rays.

[0073] The detector functions as a beam detector. In this embodiment, the detector is an HPGe detector.

[0074] Specifically, a high-purity germanium detector sequentially measures the radioactive source, and the collected data is analyzed. Then, the characteristic peaks corresponding to the radioactive source in the energy spectrum are identified. Finally, by linearly fitting the number of channels of the characteristic peaks with the known energy of the radioactive source, an energy calibration curve is determined.

[0075] A single crystal is used to monochromatize bremsstrahlung, producing a broad beam of X-rays. In this embodiment, the single crystal is a Si555 crystal.

[0076] The aperture serves to limit the beam. In this embodiment, the aperture size is 4mm, corresponding to an aperture area of ​​12.57mm². 2 .

[0077] Lead plates have excellent X-ray shielding properties. Placing a lead plate behind the aperture can effectively block scattered X-rays and reduce the interference of background noise on experimental results. In this embodiment, the lead plate has a hole for the main beam to pass through, and the position of the hole corresponds to the aperture.

[0078] It should be noted that no lead plate was used when adjusting the collimator's pose to the target pose. That is, the pose adjustment process for the collimator was completed before placing the lead plate.

[0079] In some embodiments, see Figure 2 When the bremsstrahlung parameters of the X-ray machine meet the requirements, the steps for setting up the X-ray radiation device may include:

[0080] S21, the detector is placed on the second platform, and the X-ray machine is placed on the first platform.

[0081] In this embodiment, the first platform is a turntable, such as a rotating platform.

[0082] The rotating platform is a component used to rotate the relative positions of the X-ray machine and the crystal. The rotating platform adjusts the incident angle between the X-rays emitted from the X-ray machine and the crystal plane. In Bragg diffraction, the incident direction of the X-rays and the exit direction of the monochromatic X-rays produced by diffraction follow the principle of specular reflection. If only the crystal is rotated to produce monochromatic X-rays, the exit direction of the produced monochromatic X-rays will rotate with the crystal, and the detector position will also need to change, making operation very difficult. Therefore, the monochromatic X-ray path after crystal diffraction needs to remain unchanged. The rotating platform is used to simultaneously rotate the optical engine and the crystal, with the optical engine rotating by 2θ angles and the crystal rotating by θ angles.

[0083] The detector and the second platform work together to accurately detect narrow beams of monochromatic X-rays after collimation and shielding. The detector, calibrated with the energy of a standard radiation source, becomes a standard detector. The moving platform allows for high-precision adjustment of the detector's position, ensuring it is aligned with the X-ray beam.

[0084] The mobile platform is a component that enables the detector to move with high precision in four directions: up, down, left, and right.

[0085] When using a detector to measure the generated narrow-beam monochromatic X-rays, because the beam diameter of the narrow-beam monochromatic X-rays is small, the high-purity germanium detector probe needs to be precisely aligned with the beam in order to measure the complete output narrow-beam monochromatic X-rays.

[0086] Considering the need to continuously adjust the detector position during the X-ray alignment process, a high-precision moving platform is provided to avoid radiation hazards. The detector is placed on the platform, and the position of the platform can be moved remotely to find the place where the high-purity germanium detector measures the strongest X-ray intensity, which is the emission position of the narrow beam monochromatic X-ray.

[0087] In some embodiments, the minimum moving distance of the moving platform is 1 mm to meet high precision requirements, and it can move in both horizontal and vertical directions. This platform allows for adjustment of the detector's position, ensuring the detector is directly facing the monochromatic X-rays after back-end shielding, thus improving the accuracy of the measurement process.

[0088] In some embodiments, the distance from the X-ray machine to the detector is approximately 3.5m.

[0089] S22, the single crystal is placed between the X-ray machine and the detector, and the position of the main beam transmitted to the detector via the single crystal is determined.

[0090] In some embodiments, the primary task in the initial stage of device setup is to accurately position the main beam after single-crystal diffraction using a detector. Initially, a laser is used to preliminarily adjust the horizontal and vertical positions of the high-purity germanium detector; however, laser adjustment relies solely on visual inspection and manual adjustment, resulting in significant errors. Therefore, a high-precision moving platform and detector are needed for actual measurements to locate the position where the detector measures the highest intensity of monochromatic X-rays, thus determining the final position of the high-purity germanium detector.

[0091] In some embodiments, the bremsstrahlung parameters of the X-ray machine are obtained by the detector when a preset tube voltage and tube current are applied to the X-ray machine.

[0092] The tube voltage can be in the range of 80-100kV, and the tube current should not be less than 0.5mA. In this way, a clear tungsten characteristic peak can be obtained, and the detector dead time will not be too high.

[0093] Accordingly, step S22 may include:

[0094] S221, Determine the rotation angle of the single crystal according to Bragg's formula.

[0095] In some embodiments, the tube voltage and tube current determine the energy generated by bombarding the tungsten target, and thus the rotation angle of the single crystal is determined based on the tube voltage and tube current in the sub-state and the required energy of the main beam.

[0096] Specifically, the single crystal is placed on a turntable. Since the X-ray machine used generates bremsstrahlung by bombarding a tungsten target with an electron beam, the highest radiation intensity can be obtained at 60 keV.

[0097] In this way, by setting the X-ray tube voltage to 90kV and 0.5mA, and calculating according to Bragg's formula, the crystal angle is rotated to about 9 degrees, producing 60keV of monochromatic X-rays.

[0098] For example, the Bragg diffraction formula is: nλ = 2d sinθ, where n is an integer representing the diffraction order, λ is the wavelength of the X-ray, d is the interplanar spacing of the single crystal, and θ is the incident angle.

[0099] In this embodiment, first-order diffraction is used, so n=1, and the interplanar spacing d of the single crystal is 0.0627nm. Thus, θ is determined to be 9°.

[0100] It should be noted that during the process of generating bremsstrahlung, the X-ray machine emits a wide beam of X-rays with a large divergence angle. If the crystal is far from the X-ray machine's exit port, different positions on the same crystal plane will satisfy different Bragg angles, thus reflecting mixed light of multiple wavelengths. Therefore, it is necessary to bring the crystal as close as possible to the X-ray machine's exit port.

[0101] S222, when the X-ray machine is driven to emit an outgoing beam, the second platform is driven to move in the first direction and the second direction to change the incident position of the main beam irradiating the detector through the single crystal, and to obtain the number of photons corresponding to different incident positions.

[0102] In some embodiments, a moving platform is used to move the detector with high precision in both the lateral and longitudinal directions, with a moving step size of 1 mm. This allows for the acquisition of the number of photons corresponding to different incident positions.

[0103] S223, the incident position with the highest number of photons is taken as the position of the main beam.

[0104] In some embodiments, by executing step S222, multiple photon counts can be obtained, and the incident position with the highest photon count, i.e., the position with the highest detector count, can be used as the position of the main beam.

[0105] See Figure 8 The second monochromatic X-ray energy spectrum shown in the embodiment of this application is a 60keV monochromatic X-ray energy spectrum without collimation after single crystal diffraction.

[0106] from Figure 8 As can be seen, after bremsstrahlung is diffracted by the crystal, a monochromatic peak of 60 keV is produced, but there is a high stray peak at (60-90) keV. This is because the produced monochromatic peak is mixed with the original bremsstrahlung and is detected by the detector in its entirety. Therefore, a collimator is needed to shield the original bremsstrahlung.

[0107] S23, a collimator is set along the transmission path of the main beam, and the collimator is parallel to the transmission path of the main beam.

[0108] In some embodiments, after the main beam position is determined, a collimator is placed according to the main beam position.

[0109] Specifically, a support is set between the first platform (i.e., the turntable) and the second platform (i.e., the moving platform), namely, the support for the collimator is support B and support A respectively; the collimator is placed on the support, and the horizontal and vertical directions of the two supports are initially adjusted by the laser instrument until the center of the collimator coincides with the center of the main beam.

[0110] The collimator is placed on the support, and the horizontal and vertical directions of the two supports are initially adjusted by the laser instrument until the center of the collimator coincides with the center of the main beam.

[0111] The side of the collimator aligned with the detector probe is called collimator b side, and the other side is called collimator a side.

[0112] In this embodiment, see Figure 9 The third monochromatic X-ray energy spectrum shown in this embodiment is a 60keV monochromatic X-ray energy spectrum after collimation tube beam confinement.

[0113] like Figure 9 As shown, the radiation intensity decreases after the collimator is placed, so the tube voltage and current must be increased to maintain the radiation intensity. For example, the tube voltage can be set to 100kV and the tube current to 1mA, and a detector can be used for measurement.

[0114] In other words, the tube voltage and tube current will change during the setup process.

[0115] S24, an aperture is provided on the side of the collimator near the detector to limit the main beam passing through the collimator.

[0116] In some embodiments, after placing the collimator, although the energy spectrum no longer has the previous stray peaks, the lower half of the monochromatic peak is wider. This is because the collimator diameter is too large, resulting in incomplete shielding. In addition, interference from many scattered rays necessitates the addition of an aperture at the end of the collimator to further confine the rays.

[0117] Specifically, an aperture is used to further limit the beam of X-rays. This is because a monochromatic peak can be measured after adding a collimator, but the inner diameter of the collimator is 1.5 cm, and the diameter of the X-ray beam emitted directly from the collimator is too large.

[0118] Adding a 4mm aperture reduces the diameter of the X-ray beam emitted from the collimator from 15mm to 4mm, resulting in a narrower diameter of monochromatic X-rays. However, this weakens the X-ray intensity, necessitating an increase in tube current to enhance the intensity. The tube voltage was set to 100kV and the tube current to 3mA. Measurements were taken using a detector, and the results are as follows: Figure 10 As shown.

[0119] in, Figure 10 This is the energy spectrum of a 60 keV monochromatic X-ray beam after collimation and aperture confinement. (Comparison) Figure 9 and Figure 10 Energy dispersive spectral peak shape. Without an aperture, as shown... Figure 9 As shown, although a 60keV monochromatic peak can be measured, the lower half of the peak is relatively wide; however, after adding an aperture, as... Figure 10 As shown, the half-width at half-maximum (FWHM) of the monochromatic peak is significantly reduced, the peak shape is smoother, and it better conforms to the Gaussian distribution.

[0120] Optionally, in step S25, a lead plate is disposed between the aperture and the detector, the lead plate having a hole through which the main beam passes, and the position of the hole corresponding to the aperture.

[0121] In some embodiments, the aperture constrains the X-ray propagation path by limiting the beam, effectively reducing interference from scattered rays and non-uniform incident rays, and significantly improving the monochromaticity of the X-ray beam. However, a significant number of stray counts can still be observed at the bottom, which are detected by the detector through bremsstrahlung scattering. Therefore, a lead plate with a small aperture that allows only monochromatic X-rays to pass through needs to be added behind the aperture.

[0122] Lead plates have excellent X-ray shielding properties. Placing them behind the aperture can effectively block scattered X-rays and reduce the interference of background noise on experimental results.

[0123] In this embodiment, the tube voltage is set to 100kV and the tube current to 3mA. A detector is used for measurement, and the measurement results are as follows: Figure 11 As shown.

[0124] in, Figure 11 This is a 60keV monochromatic X-ray energy spectrum after the device was installed. Figure 11 As can be seen, compared with the energy spectrum without the lead plate, the addition of the lead plate reduces the scattered X-rays in the energy spectrum, and there is only a single energy peak of 60 keV in the energy spectrum, with no scattered X-rays.

[0125] S12, adjust the pose of the collimator to the target pose.

[0126] In some embodiments, during the X-ray radiation process, the collimator's position is determined by initial positioning and manual adjustment using a laser instrument. However, this method has a problem. Human vision can produce errors, causing the center of the collimator to deviate from the center of the main beam. Although most scattering can be shielded by using an aperture limiter and lead plates, if the center of the collimator deviates from the center of the main beam, it will result in low radiation utilization and weakened radiation intensity.

[0127] Therefore, it is necessary to adjust the pose of the collimator to the target pose, that is, to make the center of the collimator coincide with the center of the main beam, thereby changing the output beam.

[0128] More specifically, step S12 may include:

[0129] S121, obtain the number of first photons of the X-ray machine's emitted beam detected by the detector within a preset time when the aperture is placed between the collimator and the detector.

[0130] Specifically, when the aperture is placed between the collimator and the detector, the aperture further confines the beam, thereby driving the X-ray machine to emit a beam that the detector can detect, and thus determine the number of the first photons.

[0131] S122, Remove the aperture and place the semi-slit aperture in its original position.

[0132] Specifically, according to the device setup process described above, the center of the collimator is offset from the center of the main beam, resulting in low X-ray utilization and weakened X-ray intensity. Therefore, this paper proposes a method using a semi-slit aperture to dynamically adjust the collimator, achieving high-precision alignment of the collimator.

[0133] Furthermore, to improve alignment accuracy, a semi-slit aperture is placed at the location of the aperture stop.

[0134] In order to ensure that the collimator is accurately aligned with the center of the main beam, the semi-slit aperture can be formed by covering half of a slit aperture with a width of 1 mm (exit area 1 mm × 15 mm = 15 mm2) with a lead block, creating a semi-slit aperture that is transparent on one side. This semi-slit aperture is then placed on the collimator on the side aligned with the detector. The position of the collimator can then be adjusted by measuring the count difference of the semi-slit aperture in different opening directions using the detector.

[0135] S123, drive the semi-slit aperture to move, and within the preset time, obtain the number of second photons of the emitted beam when the exit of the semi-slit aperture is located at different positions through the detector.

[0136] Specifically, the collimator center is offset from the main beam center, so it is necessary to obtain the number of second photons when the exit of the semi-slit stop is located at different positions.

[0137] In this embodiment, the conditions for aligning the collimator with the center of the main X-ray beam are obtained based on the Poisson distribution and the normal distribution.

[0138] That is, if the collimator is aligned with the center of the main beam, the count difference between different opening directions of the semi-slit aperture should be within a certain range. During X-ray detection, the photon count per unit time follows a Poisson distribution.

[0139] When the average number of times an event occurs is λ, the probability of observing k events is:

[0140]

[0141] The mean and square of the variance of a distribution are equal, i.e., μ = σ² = λ. When λ is large, the Poisson distribution approximates a normal distribution. In a normal distribution, approximately 95.45% of the data falls within the mean ± 2 standard deviations. Therefore, it can be concluded that the difference in counts between different opening directions of a half-slit aperture cannot exceed 2 standard deviations.

[0142] In other words, during the detection process of the emitted beam, the photon count per unit time follows a Poisson distribution.

[0143] More specifically, this application calculates the theoretical count when the detector measuring device is paired with a 4mm aperture based on the ratio of the aperture area of ​​the 4mm aperture to the aperture area of ​​the half-slit, thereby obtaining the specific standard deviation value.

[0144] In some embodiments, the preset difference is determined by determining the photon count corresponding to the light outlet of the slit aperture as λN based on the light outlet area of ​​the aperture and the light outlet area of ​​the slit aperture; and the preset difference is determined based on twice the standard deviation corresponding to the Poisson distribution.

[0145] Specifically, using a 4mm aperture for beam limiting, the detector counts N within 10 seconds. The exit area of ​​the 4mm aperture is approximately 12.57mm², the exit area of ​​the 1mm slit aperture is approximately 15mm², and the exit area of ​​the half-slit aperture is 7.5mm². Therefore, the calculated count corresponding to the exit area of ​​the half-slit aperture is approximately 0.6N, and 2 times the standard deviation is approximately... When the collimator is aligned with the center of the main beam, the counting difference between different opening directions of the semi-slit aperture cannot exceed [a certain value].

[0146] S124, adjust the pose of the collimator according to the number of second photons when the exit of the semi-slit aperture is in different positions, and the number of first photons.

[0147] In some embodiments, step S124 may include: determining the difference between the number of second photons when the exit of the semi-slit aperture is located at different positions; fixing the pose of the collimator in the optical path in response to the difference being less than a preset difference; the preset difference being determined based on the number of first photons; and adjusting the collimator according to the position of the exit corresponding to the larger number of second photons, so that the collimator moves toward the position indicated by the larger number of second photons, until the difference is less than the preset difference.

[0148] In short, if the difference is less than the preset difference, it means that the center of the collimator and the center of the main beam coincide, and no adjustment is needed; if the difference is greater than or equal to the preset difference, it means that the center of the collimator and the center of the main beam do not coincide, and adjustment is needed.

[0149] In some embodiments, after adjusting the pose of the collimator, a verification operation is further included to determine whether the center of the collimator and the center of the main beam are aligned.

[0150] The verification operation includes: removing the semi-slit aperture and placing it in its original position, and obtaining the first photon count again; removing the aperture and placing it in its original position, and obtaining the second photon count when the exit of the semi-slit aperture is located at different positions; and fixing the pose of the collimator when the difference is less than the preset difference based on the second photon count when the exit of the semi-slit aperture is located at different positions.

[0151] For more details on the verification process, please refer to the solution for the aforementioned example.

[0152] It should be noted that when adjusting the position of the collimator, the vertical direction is treated as one adjustment scheme and the horizontal direction as another adjustment scheme, and they are adjusted separately.

[0153] To better understand and illustrate the adjustment process in this application, a semi-slit aperture is used to adjust the horizontal and vertical positions of the collimating tubes a and b.

[0154] Furthermore, taking the adjustment of the horizontal position of the collimator as an example, a flowchart is given on dynamically adjusting the horizontal position of the collimator using a semi-slit aperture, and the horizontal position of the collimator is adjusted according to the flowchart.

[0155] See Figure 12 The flowchart shown in this application illustrates a specific process for adjusting a light beam based on a semi-slit aperture, as follows: Figure 12As shown, a detailed explanation of the flowchart for adjusting the collimator in the horizontal direction of the semi-slit aperture is given.

[0156] First, place the 4mm aperture in the collimating tube and measure for 10 seconds using a high-purity germanium detector, counting to N. Then remove the 4mm aperture and use a semi-slit aperture, aligning the exit of the semi-slit aperture with the left and right sides respectively. Measure for 10 seconds each time using a high-purity germanium detector. If the count difference between the left and right sides is greater than N... If the count on the left side is greater than that on the right side, use a support to adjust the collimator to the left. If the count is less, adjust it to the right. Repeat this adjustment process, placing a 4mm aperture into the collimator for measurement until the count difference between the left and right sides is less than [value missing]. End. Similarly, continuously adjust the vertical and horizontal distances on both sides of the collimator until the counts of the high-purity germanium detectors at the top, bottom, left, and right positions of the semi-slit aperture on both sides a and b are not significantly different. At this point, the collimator is considered to be at the center of the main beam of monochromatic X-rays.

[0157] Furthermore, adjusting the collimator position using a semi-slit aperture significantly increases the beam intensity. Removing the semi-slit aperture and adding a 4mm aperture, the energy spectra before and after adjustment with the semi-slit aperture were recorded. The measurement time was 100 seconds. Using a 4mm aperture, the energy spectra were fitted as follows: Figure 13 As shown.

[0158] from Figure 13 As can be seen, after calibration with a half-slit aperture, the peak value of monochromatic X-rays increased from 4500 to 6200, the X-ray utilization rate increased by 38%, and the full width at half maximum (FWHM) of the 60 keV main peak narrowed from 1.2 keV to 0.8 keV, indicating that scattering interference was significantly reduced and the monochromaticity of monochromatic X-rays was further improved.

[0159] In summary, this application mainly focuses on a single-crystal monochromatic X-ray radiation device, describing in detail the entire device composition, including the X-ray source, beam-limiting components, detector, and moving platform. Taking a monochromatic peak of 60 keV as an example, the construction process of the device is elaborated in detail. Through five steps—measuring bremsstrahlung, positioning the single-crystal diffraction main beam, collimating tube beam limiting, aperture beam limiting, and lead plate shielding—a single-crystal monochromatic X-ray radiation device based on Si555 crystal was successfully constructed.

[0160] This paper proposes a method for dynamically adjusting the collimator using a semi-slit aperture. Based on the Gaussian distribution, the count difference between the left and right sides of the semi-slit aperture is experimentally measured. When the count difference exceeds twice the standard deviation, the collimator is continuously adjusted towards the side with the higher count until the count difference between the left and right sides of the semi-slit aperture is less than twice the standard deviation. The results show that after calibration with the semi-slit aperture, the X-ray utilization rate is improved, the monochromaticity of monochromatic X-rays is enhanced, and high-precision alignment of the collimator is achieved.

[0161] Thus, this application has at least the following advantages over existing solutions:

[0162] 1. Improved accuracy: After calibration with a half-slit aperture, the peak value of monochromatic X-rays increased from 4,500 to 6,200, the X-ray utilization rate increased by 38%, and the full width at half maximum (FWHM) of the 60 keV main peak narrowed from 1.2 keV to 0.8 keV.

[0163] 2. Improved Device Performance: The device successfully generated monochromatic X-rays with an energy range of (40-150) keV that is continuously adjustable. Under conditions of a tube voltage of 200 kV and a tube current of 3 mA, the 150 keV monochromatic peak achieved a count of 21682 cps over 100 seconds with a full width at half maximum (FWHM) of 2.21 keV. Based on the detector energy resolution formula and the measured energy resolution, the monochromaticity of the X-rays produced by the constructed monochromatic X-ray radiation device is better than 1.45%.

[0164] In the stability test, with a tube voltage of 200kV and a tube current of 3mA, the relative deviation of the current was only 0.87%, indicating good output stability of the X-ray machine.

[0165] This application also provides an X-ray radiation device, such as Figure 6 As shown, an X-ray radiation device may include: an X-ray machine, a single crystal, a collimator, an aperture, and the detector, which are placed sequentially along the optical path.

[0166] For further descriptions of X-ray radiation devices, please refer to the examples above.

[0167] The X-ray radiation device employs a beam adjustment based on a semi-slit aperture as described in any of the claims of this application, adjusting the X-ray beam by adjusting the position of the collimator.

[0168] In some embodiments, the X-ray radiation device may further include:

[0169] A lead plate is disposed between the aperture and the detector, and the lead plate has a hole through which the main beam passes, and the position of the hole corresponds to the aperture.

[0170] The first platform is used to support the X-ray machine. The details of the first platform can be found in the aforementioned example.

[0171] The second platform is used to carry the detector. The details of the second platform can be found in the aforementioned example.

[0172] A support, located between the first and second platforms, is used to support the collimation tube. The details of the support can be found in the aforementioned example.

[0173] In this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0174] Furthermore, in this invention, the use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0175] While the embodiments disclosed above are provided, the present invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for adjusting a light beam based on a semi-slit aperture, characterized in that, include: When the bremsstrahlung parameters of the X-ray machine meet the requirements, an X-ray radiation device is set up. The X-ray radiation device includes an X-ray machine, a single crystal, a collimator, an aperture, and a detector, which are placed sequentially along the optical path. Adjusting the pose of the collimator to a target pose includes: acquiring the number of first photons of the X-ray machine's output beam detected by the detector within a preset time when the aperture is placed between the collimator and the detector; removing the aperture and placing a semi-slit aperture in its original position; driving the semi-slit aperture to move, and acquiring the number of second photons of the output beam detected by the detector when the exit of the semi-slit aperture is located at different positions within the preset time; and adjusting the pose of the collimator based on the number of second photons when the exit of the semi-slit aperture is located at different positions and the number of first photons.

2. The method for adjusting the beam according to claim 1, characterized in that, The step of adjusting the pose of the collimator based on the number of second photons when the exit of the semi-slit aperture is at different positions, and the number of first photons, includes: Determine the difference in the number of second photons when the exit of the semi-slit aperture is located at different positions; When the difference is less than a preset difference, the pose of the collimator in the optical path is fixed; the preset difference is determined based on the first photon count. When the difference is not less than a preset difference, the collimator is adjusted according to the position of the exit corresponding to the larger number of second photons, so that the collimator moves toward the position indicated by the larger number of second photons until the difference is less than the preset difference.

3. The method for adjusting the beam according to claim 2, characterized in that, After adjusting the pose of the collimator, a verification operation is also included; The verification operation includes: removing the semi-slit aperture and placing it in its original position, and obtaining the first photon count again; removing the aperture and placing it in its original position, and obtaining the second photon count when the exit of the semi-slit aperture is located at different positions; and fixing the pose of the collimator when the difference is less than the preset difference based on the second photon count when the exit of the semi-slit aperture is located at different positions.

4. The method for adjusting the beam according to claim 2 or 3, characterized in that, Meet one or more of the following conditions: During the detection of the emitted beam, the photon count per unit time follows a Poisson distribution; The preset difference is determined by using the light exit area of ​​the aperture and the light exit area of ​​the slit aperture to determine the photon count corresponding to the light exit of the slit aperture as λN; and by using 2 times the standard deviation corresponding to the Poisson distribution to determine the preset difference. After fixing the position of the collimator, the process also involves removing the semi-slit aperture and placing it back in place. The light exit area of ​​the aperture is 12.57 mm². 2 The preset time is 10 seconds, and the photon count is N. The light exit area of ​​the semi-slit aperture is 7.5 mm². 2 The corresponding photon count is 0.6N, and the standard deviation is 1.55√N.

5. The method for adjusting the beam according to claim 1, characterized in that, When the bremsstrahlung parameters of the X-ray machine meet the requirements, the X-ray radiation device is set up, including: The detector is placed on the second platform, and the X-ray machine is placed on the first platform; The single crystal is placed between the X-ray machine and the detector, and the position of the main beam transmitted to the detector via the single crystal is determined. A collimator is provided along the transmission path of the main beam, and the collimator is parallel to the transmission path of the main beam. An aperture is provided on the side of the collimator near the detector to limit the main beam passing through the collimator; A lead plate is placed between the aperture and the detector. The lead plate has a hole through which the main beam passes, and the position of the hole corresponds to that of the aperture.

6. The method for adjusting the beam according to claim 5, characterized in that, The bremsstrahlung parameters of the X-ray machine are obtained by the detector when a preset tube voltage and tube current are applied to the X-ray machine. The step of placing the single crystal between the X-ray machine and the detector, and determining the position of the main beam transmitted to the detector via the single crystal, includes: The rotation angle of the single crystal is determined according to Bragg's formula. When the X-ray machine is driven to emit an outgoing beam, the second platform is driven to move in the first direction and the second direction, changing the incident position of the main beam irradiating the detector through the single crystal, and obtaining the number of photons corresponding to different incident positions; The incident position with the highest number of photons is taken as the position of the main beam.

7. The method for adjusting the beam according to claim 5, characterized in that, The provision of a collimator along the transmission path of the main beam, and the collimator being parallel to the transmission path of the main beam, includes: A support frame is installed between the first platform and the second platform; The collimator is placed on the support, and the horizontal and vertical directions of the two supports are initially adjusted by the laser instrument until the center of the collimator coincides with the center of the main beam.

8. The method for adjusting the beam according to claim 1, characterized in that, Meet one or more of the following conditions: The X-ray machine emits monochromatic X-ray beams; The single crystal is a Si555 crystal; The detector is an HPGe detector.

9. An X-ray radiation device, characterized in that, include: The X-ray machine, single crystal, collimator, aperture, and detector are placed sequentially along the optical path. The X-ray radiation device employs a beam adjustment method based on a semi-slit aperture as described in any one of claims 1 to 8, adjusting the X-ray beam by adjusting the position of the collimator.

10. The X-ray radiation device according to claim 9, characterized in that, Also includes: A lead plate is disposed between the aperture and the detector, and the lead plate has a hole for the main beam to pass through, and the position of the hole corresponds to the aperture; The first platform is used to support the X-ray machine; The second platform is used to carry the detector; A support, located between the first platform and the second platform, is used to support the collimation tube.

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