A method for calibrating full field full spectrum response efficiency of a KB microscope

Abstract

The present application relates to the technical field of inertial confinement fusion measurement, and particularly relates to a kind of KB microscope full field full spectral response efficiency calibration method, comprising: obtaining the system response efficiency measured value of the microscope to be calibrated at at least one discrete energy point, at at least one selected position in object field;System response efficiency theoretical model of the microscope to be calibrated is constructed, theoretical model will system response efficiency be characterized as the function of object field position and incident X-ray wavelength variation, and contain at least one correction parameter for characterizing the deviation between actual system and ideal model;System response efficiency measured value and the calculation result of theoretical model under the same conditions are compared and fitted to correct correction parameter, and the corrected theoretical model is obtained;Using the corrected theoretical model, the system response efficiency of the microscope to be calibrated in the entire object field and the continuous spectral range is determined.

Description

Technical Field

[0001] This invention relates to the field of inertial confinement fusion measurement technology, specifically to a method for calibrating the full-field, full-spectrum response efficiency of a KB microscope. Background Technology

[0002] Laser-driven inertial confinement fusion experiments generate broadband X-ray radiation, and accurate quantitative imaging of its intensity and energy spectrum is crucial for diagnosing plasma states and nuclear reaction processes. The KB microscope, a widely used X-ray imaging device in these experiments, consists of two orthogonally placed spherical or cylindrical mirrors, offering significant advantages in both high spatial resolution and high imaging efficiency. By depositing a specifically structured reflective film on the mirror surface, targeted energy spectrum response functions can be achieved, making it vital in X-ray imaging diagnosis. However, the system response efficiency of the KB microscope varies significantly with both the imaging field of view position and the incident X-ray wavelength. This complex spatial and spectral coupling characteristic makes achieving full-field-of-view, full-spectrum response efficiency calibration a pressing technical challenge in this field.

[0003] In existing technologies, one type of method uses a laboratory X-ray source combined with pinhole scanning for calibration: characteristic X-rays are used as a quasi-monoenergetic source, and the position of the incident light on the microscope to be calibrated is changed by moving the objective aperture. The incident and emitted spectral intensities are measured separately to calculate the response efficiency at a specific location at a single characteristic energy point. Simultaneously, to obtain more comprehensive aperture information, existing technologies have optimized the optical path layout by moving the aperture stop to the front of the spectrometer to measure the full aperture response. Although existing technologies have been researched and improved for KB microscope response efficiency calibration, significant drawbacks remain, making it difficult to achieve high-precision full-field-of-view, full-spectrum response efficiency calibration for KB microscopes. First, the moving pinhole scanning measurement method relies on mechanically scanning discrete field points, a time-consuming process that can only acquire data from a limited number of locations, failing to efficiently and completely obtain the distribution of response efficiency across the entire continuous field of view. Secondly, the characteristic X-ray spectral lines generated by laboratory light sources are essentially discrete quasi-monoenergetic rays. Their calibration results only correspond to specific energies and cannot directly obtain the response function of the microscope in a continuous spectral range. This makes it difficult to meet the practical application requirements for quantitative analysis of X-ray intensity in laser inertial confinement fusion X-ray imaging, thus limiting the further application of KB microscopes in high-precision X-ray imaging diagnosis. Summary of the Invention

[0004] To achieve high-precision calibration of the full-field-of-view and full-spectrum response efficiency of a KB microscope, this invention provides a method for calibrating the full-field-of-view and full-spectrum response efficiency of a KB microscope. The specific technical solution adopted is as follows:

[0005] The first aspect of the present invention provides a method for calibrating the full-field, full-spectrum response efficiency of a KB microscope, the method comprising:

[0006] Obtain the measured system response efficiency of the microscope to be calibrated at at least one selected position in the object-side field of view at at least one discrete energy point;

[0007] A theoretical model of the system response efficiency of the microscope to be calibrated is constructed. The theoretical model characterizes the system response efficiency as a function of the object-side field position and the incident X-ray wavelength, and includes at least one correction parameter to characterize the deviation between the actual system and the ideal model.

[0008] The measured values ​​of the system response efficiency are compared and fitted with the calculation results of the theoretical model under the same conditions to correct the correction parameters and obtain the corrected theoretical model.

[0009] Using the modified theoretical model, the system response efficiency of the microscope to be calibrated is determined within the entire object field of view and the continuous spectral range.

[0010] Furthermore, obtain the measured values ​​of the system response efficiency, including:

[0011] A pinhole is placed on the object side of the microscope to be calibrated to limit the beam of X-rays emitted from the X-ray source, forming a point-like X-ray source at the selected object side field of view.

[0012] At the image plane position of the microscope to be calibrated, the emitted spectral intensity at the image point obtained after imaging by the microscope to be calibrated is measured using the first spectral detector.

[0013] In the object side of the microscope to be calibrated, the second spectral detector is placed on the line connecting the point X-ray source and the center of the mirror of the microscope to be calibrated, and the intensity of the incident spectrum when the microscope is not being calibrated is measured.

[0014] Calculate the measured system response efficiency at the selected location based on the emitted and incident spectral intensities.

[0015] Furthermore, obtaining the measured values ​​of system response efficiency also includes:

[0016] By changing the position of the pinhole on the object plane, the measured values ​​of the system response efficiency at multiple different selected positions of the microscope to be calibrated at at least one direction within the object field of view are obtained.

[0017] Furthermore, a theoretical model of the system response efficiency of the microscope to be calibrated is constructed, including:

[0018] Calculate the product of the X-ray focusing solid angle of the microscope to be calibrated and its reflectivity;

[0019] The system response efficiency is calculated based on the product and the magnification of the microscope to be calibrated.

[0020] Furthermore, the reflectance is calculated by multiplying the reflectance of the front mirror and the reflectance of the rear mirror in the microscope to be calibrated.

[0021] Furthermore, the light-gathering solid angle is calculated based on the length of the mirror of the microscope to be calibrated, the object distance, and the grazing incident angle.

[0022] Furthermore, the correction parameters include the grazing incidence angle parameter at the center of the field of view and the intensity correction factor;

[0023] The grazing incidence angle parameter at the center of the field of view is used to adjust the position of the system response efficiency distribution curve of the theoretical model in the field of view.

[0024] The intensity correction factor, as a product factor, is used to adjust the intensity of the system response efficiency of the theoretical model.

[0025] Furthermore, the measured values ​​of the system response efficiency are compared and fitted with the calculation results of the theoretical model, including:

[0026] Based on the measured system response efficiency at a single discrete energy point, a distribution curve of the measured efficiency as a function of the field of view position is generated.

[0027] The theoretical model is used to calculate the theoretical value of the system response efficiency under the same discrete energy point and the same field of view position, and the theoretical calculation distribution curve is generated.

[0028] Using the measured distribution curve as a benchmark, the values ​​of the correction parameters are iteratively adjusted to minimize the preset difference between the theoretically calculated distribution curve and the measured distribution curve, thereby fitting the correction parameters.

[0029] Furthermore, the preset difference metric is the minimum mean square error, the root mean square error, or the mean absolute error.

[0030] Furthermore, using the modified theoretical model, the system response efficiency of the microscope to be calibrated is determined across the entire object-side field of view and the continuous spectral range, including:

[0031] Input the target's position coordinates within its field of view and the wavelength values ​​within its continuous spectral range into the corrected theoretical model;

[0032] The system response efficiency value is calculated and output from the modified theoretical model to obtain the system response efficiency distribution at any position in the field of view of the target object of the microscope to be calibrated, and at any wavelength in the continuous spectrum of the target.

[0033] The present invention has the following beneficial effects:

[0034] The present invention provides a method for calibrating the full-field-of-view, full-spectrum response efficiency of a KB microscope. This method acquires experimental measurement data from a limited number of discrete energy points and partial field-of-view locations, constructs and corrects a theoretical model of the system response efficiency including key deviation parameters, and then uses this corrected model to calculate the response efficiency across the entire field of view and the continuous spectral range. This method combines limited experimental calibration with physical model extrapolation, eliminating the need for individual measurements at all locations across the entire field of view and at all energy points across the entire spectrum. This overcomes the limitations of existing point-by-point scanning calibration methods, which are inefficient, and the difficulty in obtaining continuous spectral response functions relying on single-energy point light sources. Furthermore, the correction parameters are calibrated by comparing and fitting the measured values ​​with the theoretical model, ensuring accurate adaptation between the theoretical model and the actual system. This invention can efficiently and accurately obtain the full-field-of-view, full-spectrum response efficiency calibration of a KB microscope, meeting the core application requirement of quantitative X-ray intensity analysis in laser inertial confinement fusion X-ray imaging. Attached Figure Description

[0035] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of the embodiments of the invention in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same parts or steps.

[0036] Figure 1 This is a schematic flowchart of a full-field-of-view, full-spectrum response efficiency calibration method for a KB microscope provided in an exemplary embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the correction of the KB microscope response efficiency calculation parameters provided in an exemplary embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram illustrating the calculation of the full-field, full-spectrum response efficiency of the KB microscope using a modified model provided in an exemplary embodiment of the present invention. Detailed Implementation

[0039] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0040] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0041] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0042] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0043] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0044] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0045] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0046] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0047] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0048] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0049] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0050] Example 1

[0051] Figure 1 This is a schematic flowchart of a full-field-of-view, full-spectrum response efficiency calibration method for a KB microscope provided in an exemplary embodiment of the present invention. The method can be executed by a calibration system equipped with a corresponding X-ray source, spectral detection, and data processing capabilities.

[0052] Specifically, refer to Figure 1The method for calibrating the full-field, full-spectrum response efficiency of the KB microscope includes:

[0053] Step 100: Obtain the measured system response efficiency of the microscope to be calibrated at at least one discrete energy point and at at least one selected location in the object-side field of view. This step provides crucial experimental baseline data for subsequent model correction. In practice, the calibration optical path is first constructed, and a precision pinhole is placed in the object side of the KB microscope to limit the beam emitted from the laboratory X-ray source, thereby forming a point-shaped X-ray source of a defined size at the selected object-side field of view location.

[0054] Subsequently, two-stage spectral measurements were performed:

[0055] In the first stage, at the image plane position of the KB microscope, a high-resolution spectral detector is used to measure the intensity of the emitted spectrum after focusing and imaging by the KB microscope.

[0056] In the second stage, keeping the positions of the light source and pinhole unchanged, the spectral detector is moved to the object side and placed at a specific position on the line connecting the center of the point light source and the center of the KB microscope mirror. After removing the KB microscope, the incident spectral intensity is directly measured. Finally, based on the measured output and incident spectral intensities, and considering the ratio between the solid angle subtended by the pinhole at the selected position and the theoretical light-gathering solid angle of the KB microscope, calculations are performed. Thus, the measured system response efficiency corresponding to the characteristic energy point (i.e., discrete energy point) of the X-ray source at the selected position can be obtained. To obtain the variation trend along the field of view, the position of the pinhole on the object plane can be changed using a precision displacement stage, and the above measurement and calculation process can be repeated to obtain the measured system response efficiency values ​​of the KB microscope at multiple different selected positions distributed horizontally or vertically within the object field of view.

[0057] Step 200: Construct a theoretical model of the system response efficiency of the microscope to be calibrated. This theoretical model characterizes the system response efficiency as a function of the object-side field-of-view position and the incident X-ray wavelength, and includes at least one correction parameter to characterize the deviation between the actual system and the ideal model. This step aims to establish a fundamental mathematical model that can physically describe the spatial and spectral distribution of the KB microscope's response efficiency. The light-gathering solid angle is calculated from the mirror length, object distance, and the grazing incidence angle determined by the field-of-view position; reflectivity is characterized as the product of the reflectivities of the front and rear mirrors. Crucially, this model introduces correction parameters to quantify the deviation between the actual system and the ideal design, primarily including the grazing incidence angle parameter at the field-of-view center and an intensity correction factor.

[0058] Step 300: Compare and fit the measured system response efficiency values ​​with the calculation results of the theoretical model under the same conditions to correct the correction parameters and obtain the corrected theoretical model. Specifically, firstly, based on the multiple measured system response efficiency values ​​obtained in Step 100, distributed along at least one field of view direction at a single discrete energy point, a distribution curve of the measured efficiency values ​​as a function of the object-side field of view position is generated. Simultaneously, the same field of view position coordinates and the wavelength corresponding to the discrete energy point are substituted into the initial theoretical model constructed in Step 200 to calculate a series of theoretical system response efficiency values ​​and generate a theoretical calculation distribution curve. Then, using the measured distribution curve as a benchmark, the values ​​of the grazing incidence angle parameter at the field of view center and the intensity correction factor in the theoretical model are adjusted through an iterative algorithm to minimize the difference between the theoretical calculation distribution curve and the measured distribution curve. When the theoretical curve and the experimental curve achieve optimal fit, the fitting of the correction parameters is complete, thus obtaining a corrected theoretical model that is calibrated with experimental data and better conforms to the actual physical system.

[0059] Step 400: Using the modified theoretical model, determine the system response efficiency of the microscope to be calibrated within the entire object-space field of view and the continuous spectral range. After obtaining the modified theoretical model, input all position coordinates within the target object-space field of view and any wavelength value within the target continuous spectral range as input parameters, and substitute them into the model in batches. The modified theoretical model will automatically calculate and output the system response efficiency value corresponding to each "position-wavelength" combination. Through this process, without the need for complex full-field scanning and full-spectrum measurements, the complete system response efficiency distribution data of the KB microscope at any spatial point within the entire object-space field of view and at any energy point within the entire continuous spectral range can be obtained efficiently and accurately, thereby completing high-precision full-field, full-spectrum response efficiency calibration.

[0060] As described above, the full-field-of-view, full-spectrum response efficiency calibration method for the KB microscope provided by this invention acquires experimental measurement data from a limited number of discrete energy points and partial field-of-view locations, constructs and corrects a theoretical model of the system response efficiency including key deviation parameters, and then uses this corrected model to calculate the response efficiency across the entire field of view and the continuous spectral range. This method combines limited experimental calibration with physical model extrapolation, eliminating the need to measure each location in the entire field of view and each energy point in the entire spectrum individually. This overcomes the limitations of existing point-by-point scanning calibration methods, which are inefficient, and the difficulty in obtaining continuous spectral response functions by relying on single-energy point light sources. Simultaneously, the calibration of the correction parameters is completed by comparing and fitting the measured values ​​with the theoretical model, ensuring accurate adaptation between the theoretical model and the actual system. This invention can efficiently and accurately obtain the full-field-of-view, full-spectrum response efficiency calibration of the KB microscope, meeting the core application requirement of quantitative X-ray intensity analysis in laser inertial confinement fusion X-ray imaging.

[0061] Example 2

[0062] Based on the above embodiment 1, as an optional implementation method, obtaining the measured value of system response efficiency includes:

[0063] Step 110: Place a pinhole on the object side of the microscope to be calibrated to confine the X-rays emitted from the X-ray source, forming a point-like X-ray source at the selected object-side field of view. In practice, a pinhole with a known aperture size, such as a metal pinhole with a diameter of tens of micrometers, must be selected. This pinhole is fixed at the designed object-side position of the KB microscope to be calibrated. The X-ray source used is typically a laboratory-sealed X-ray tube, whose anode material generates characteristic X-ray radiation after being bombarded by electrons. After adjusting the tube's operating parameters and stabilizing its output, the emitted X-ray beam is confined by the pinhole, forming a divergent, approximately point-like source in the space behind the pinhole, whose angular distribution is determined by the pinhole's aperture and geometry. The object-side field of view position of this source is defined by the center coordinates of the pinhole relative to the microscope's optical axis.

[0064] Step 120: At the image plane position of the microscope to be calibrated, use the first spectral detector to measure the emitted spectral intensity at the image point obtained after imaging by the microscope to be calibrated. Under the illumination of the point light source formed in step 110, the KB microscope will focus the light onto a single image point on the image plane. After locating the image point area on the image plane using an optical CCD camera, move the first spectral detector to the center of the image point using a precision displacement stage. Under the same X-ray source emission conditions, collect the X-ray energy spectrum over a certain period of time. This energy spectrum includes the emitted spectral intensity distribution after considering the combined effects of system transmittance, reflectance, etc.

[0065] Step 130: In the object space of the microscope to be calibrated, place the second spectrometer on the line connecting the point X-ray source and the center of the mirror of the microscope to be calibrated, and measure the incident spectral intensity without the microscope being calibrated. After completing the measurement in step 120, keeping the positions of the X-ray source and the pinhole unchanged, move the second spectrometer to the object space. The center of the detector's sensitive surface is located on the line defined by the point source formed in step 110 and the geometric center of the first mirror of the KB microscope, and at a known distance from the source to ensure that the measured photon flux is within the linear response range of the detector. With this configuration, the X-rays bypass the KB microscope and reach the detector directly from the source, obtaining the incident spectral intensity.

[0066] Step 140: Calculate the measured system response efficiency at the selected location based on the emitted and incident spectral intensities. After obtaining the emitted and incident spectral intensities corresponding to the same selected field of view, the calculation must be based on radiometric principles. The measured system response efficiency is obtained by multiplying the ratio of the emitted to the incident intensities by a solid angle correction factor. This correction factor is the ratio of the solid angle subtended by the pinhole to the microscope's front mirror to the theoretical light-gathering solid angle of the microscope at that field of view. Through this calculation, the measured system response efficiency, which eliminates the influence of measurement geometric differences and reflects the microscope's own physical properties, can finally be obtained.

[0067] Example 3

[0068] Based on Embodiments 1 and 2 above, as an optional implementation, obtaining the measured system response efficiency further includes: by changing the position of the pinhole on the object plane, obtaining the measured system response efficiency at multiple different selected positions of the microscope to be calibrated distributed along at least one direction within the object field of view. At each selected new position, i.e., each new object field of view coordinate point, the complete measurement process of steps 110 to 140 detailed in Embodiment 2 is repeated. It should be particularly noted that, in the preferred full aperture measurement mode of this scheme, during the entire scanning measurement process, no additional aperture stop is placed at the front end of the KB microscope to limit the beam to only illuminating the central area of ​​the mirror surface, thereby ensuring that each measurement is the full aperture response efficiency of the entire reflecting mirror surface of the microscope at that field of view point, so that the experimental conditions are consistent with the calculation premise of the theoretical model.

[0069] Example 4

[0070] Based on the above embodiments 1, 2, and 3, as an optional implementation method, a theoretical model of the system response efficiency of the microscope to be calibrated is constructed, including:

[0071] Step 210: Calculate the product of the X-ray focusing solid angle and the reflectivity of the microscope to be calibrated. The reflectivity is calculated by multiplying the reflectivity of the front and rear mirrors of the microscope. The reflectivity of the mirrors is a function of the grazing angle of incidence and the X-ray wavelength. In practice, the focusing solid angle of the KB microscope to be calibrated at a specific object-side field of view position needs to be calculated first. The focusing solid angle is expressed as...

[0072]

[0073] In the formula, This indicates the effective length of a single reflecting mirror in a KB microscope. This indicates the grazing angle of X-ray incidence on the horizontally reflecting mirror; This indicates the grazing angle of X-ray incidence on the vertically reflecting mirror; Indicates the object distance from the object point to the horizontal reflecting mirror; This indicates the object distance from the object point to the vertically reflecting mirror.

[0074] Secondly, it is necessary to calculate the reflectivity of the system at the same location and wavelength. The reflectivity calculation is based on multilayer film reflection theory, treating the overall system reflectivity as the product of the reflectivities of the front and rear mirrors. The reflectivity of a single mirror is a function of its coating structure, the incident X-ray wavelength, and the grazing incidence angle. Its theoretical value can be obtained through numerical simulation using specialized X-ray optics software such as IMD. Therefore, the physical meaning of this product lies in comprehensively characterizing the total energy loss of X-rays as they pass through the two mirrors sequentially. The reflectivity decomposition model can be expressed as:

[0075]

[0076] In the formula, Indicates the position of the KB microscope in the object-side field of view. Location, relative wavelength The system reflectivity of incident X-rays; Indicates the position of the front reflecting mirror in the field of view. ,wavelength Reflectivity at the specified level; Indicates the position of the rear reflector in the field of view. ,wavelength The reflectivity of the sample.

[0077] Step 220: Calculate the system response efficiency based on the product and the magnification of the microscope to be calibrated; this step converts the product result obtained in step 210 into the final system response efficiency. In practice, magnification is an inherent imaging property of the microscope, usually a known design value or a fixed parameter calibrated through independent measurement. The system response efficiency of the KB microscope can be expressed as:

[0078]

[0079] In the formula, Indicates the position of the KB microscope in the object-side field of view. Location, relative wavelength The system response efficiency of incident X-rays; Indicates the position of the KB microscope in the object-side field of view. The corresponding solid angle of light collection at that location; Indicates the position of the KB microscope in the object-side field of view. Location, relative wavelength The system reflectivity of incident X-rays; This indicates the magnification of the KB microscope in the horizontal direction; This represents the vertical magnification of the KB microscope; where the product of the light-gathering solid angle and reflectivity essentially describes the microscope's ability to capture and reflect incident X-ray photons, while the magnification describes the scale transformation during the imaging process. The final system response efficiency is defined as a conversion efficiency coefficient that is independent of the image plane size and describes the conversion of unit incident intensity at the object plane to signal intensity at the image plane.

[0080] This embodiment analyzes the comprehensive physical quantity of system response efficiency as a clear functional relationship of basic physical parameters such as light-gathering solid angle, reflectivity, and magnification. By decomposing reflectivity and defining the geometric definition of light-gathering solid angle, the model incorporates the variation of response efficiency with field of view position and wavelength, enabling the model to extrapolate from local experimental data to global predictions.

[0081] Example 5

[0082] Based on the above embodiments 1, 2, 3, and 4, as an optional implementation, the correction parameters include a grazing incidence angle parameter at the center of the field of view and an intensity correction factor; wherein, the grazing incidence angle parameter at the center of the field of view is used to adjust the position of the system response efficiency distribution curve of the theoretical model on the field of view; the intensity correction factor, as a product factor, is used to adjust the intensity of the system response efficiency, so that the intensity calculated by the corrected theoretical model matches the measured value. During the development of the KB microscope, coating structure deviation, mirror assembly deviation, mirror surface roughness, and reflection changes caused by thin film aging are the main factors affecting the deviation of the KB microscope's response efficiency distribution from the theoretical value. Coating structure information can be tested using an X-ray diffractometer. The reflectivity of the KB microscope varies with the incident angle; the field of view position (x, y) and the grazing incidence angle (x, y) are related. The correspondence can be represented by the deviation correction model as follows:

[0083]

[0084] In the formula, This represents the actual grazing angle of X-ray incidence on the horizontal mirror at the center of the field of view; This represents the actual grazing angle of X-ray incidence on the vertical mirror at the center of the field of view; This indicates the installation rotation angle of the horizontally oriented reflector relative to the optical axis; This indicates the installation rotation angle of the vertical reflecting mirror relative to the optical axis; assembly deviations cause the grazing incidence angle to... The deviation from the design value, the field of view position (x,y) and the grazing incidence angle ( The deviation in the correspondence indicates an overall shift in the response efficiency curve. Mirror roughness and thin-film aging do not affect the reflectivity distribution but do decrease reflectivity intensity; therefore, an intensity correction factor is added. make Based on the experimental results, the grazing incidence angle at the center of the field of view (0,0) is fitted. ) and intensity correction factor This allows for the calculation of the response efficiency distribution across the entire field of view and spectrum of the KB microscope. In practice, the calculation is performed using a given deviation correction model formula based on the orthogonal optical path geometry of the KB microscope. In this formula, in addition to the known object distance, mounting rotation angle, and field of view coordinates, the grazing incidence angle parameter at the field of view center is also considered. and These are the core variables to be determined, representing the angle at which X-rays actually strike the front and rear mirrors at the center of the field of view. When assembly deviations cause the actual optical path to deviate from the design, these two parameters can be adjusted through subsequent fitting to accurately correct the calculation of the corresponding grazing incidence angle from any point on the object surface to the two mirrors, thereby correcting the systematic shift of the entire response efficiency distribution curve in the field of view caused by assembly errors.

[0085] After calculating the ideal system response efficiency for a certain field of view and wavelength using a theoretical model, it is then combined with a unified intensity correction factor. Multiplying these factors yields the corrected predicted response efficiency value. This factor is a scalar independent of position and wavelength, its physical essence being to comprehensively compensate for the difficult-to-describe overall performance degradation introduced during manufacturing and use, such as specular micro-roughness scattering, multilayer film interface diffusion, and thin film aging. This manifests as a proportional decrease in the overall reflection efficiency of the entire system. The measured system response efficiency values ​​at a single energy point for multiple field-of-view positions distributed along a certain direction, obtained in Example 3, are compared with the initial values ​​calculated by the theoretical model at the same energy point and position. Through a nonlinear optimization algorithm, the grazing incidence angle parameter at the field-of-view center and the intensity correction factor are adjusted simultaneously to minimize the overall difference between the theoretically calculated response efficiency distribution curve and the experimentally measured distribution curve, such as its minimum mean square error. When the fitting is complete, the resulting sum is a set of calibration parameters for the actual physical state of the microscope to be calibrated.

[0086] After obtaining the optimal correction parameters after fitting, they are fixed and substituted into the theoretical model. At this point, the model is transformed from an ideal design model into a calibration model for this specific microscope. For any given object-side field-of-view coordinates and target wavelength, the model will automatically calculate the grazing incidence angle using the calibrated geometric mapping and adjust the reflectivity using the calibrated intensity factor, ultimately outputting a high-confidence predicted value for the system response efficiency.

[0087] This embodiment systematically introduces geometric deviation parameters and intensity correction factors with clear physical meaning, and uses limited experimental data to fit them as a whole. This effectively calibrates the ideal physical model, which might have been distorted due to manufacturing and assembly errors and performance degradation, into a model that can reflect the true state of a specific microscope. This process allows for global prediction using calibration data from local points, solving the problem of theoretical models being detached from practical applications and ensuring the accuracy and reliability of the full-field-of-view, full-spectrum response efficiency prediction results.

[0088] Example 6

[0089] Based on the above embodiments 1, 2, 3, 4, and 5, as an optional implementation method, the measured values ​​of system response efficiency are compared and fitted with the calculation results of the theoretical model, including:

[0090] Step 310: Based on the measured system response efficiency at a single discrete energy point, generate a distribution curve of the measured efficiency as a function of the field of view position; for specific implementation, refer to... Figure 2 As shown, by extracting the measured system response efficiency values ​​from Example 3, all data points are plotted in a coordinate system with the object-side field-of-view coordinates as the horizontal axis and the corresponding measured system response efficiency values ​​as the vertical axis. Based on the distribution trend of the data points, a continuous measured efficiency distribution curve is generated using methods such as linear interpolation or smooth fitting. This curve reflects the experimental observation results of the microscope's response efficiency changing along the field-of-view direction at this specific energy point.

[0091] Step 320: Calculate the theoretical value of the system response efficiency under the same discrete energy point and the same field of view using the theoretical model, and generate the theoretical calculation distribution curve; for specific implementation, refer to... Figure 2 As shown, the exact same object-side field-of-view position coordinate sequence and the exact same characteristic X-ray wavelength used in step 310 are used as input parameters and substituted into the uncorrected or initial parameter-equipped theoretical models constructed in Examples 4 and 5. For each input position coordinate, the model calculates the corresponding theoretical value of the system response efficiency. The theoretical values ​​of all position points are plotted with the position coordinates on the horizontal axis and the theoretical efficiency value on the vertical axis to generate a theoretical calculation distribution curve. At this time, the correction parameters in the model are the initial estimates or design values.

[0092] Step 330: Using the measured distribution curve as a benchmark, the values ​​of the correction parameters are iteratively adjusted to minimize the preset difference metric between the theoretically calculated distribution curve and the measured distribution curve, thus fitting the correction parameters. The preset difference metric is the minimum mean square error, root mean square error, or mean absolute error. Specifically, a preset difference metric, such as the minimum mean square error, is defined to quantify the difference between the two curves. Within a reasonable physical range, the numerical combination of the correction parameters in the theoretical model is systematically changed. Each time the parameter combination is changed, step 320 is re-executed to generate a new theoretically calculated curve, and the difference metric between this curve and the measured distribution curve obtained in step 310 is calculated. The goal of the optimization algorithm is to find the specific set of correction parameters that minimizes this difference metric. When the algorithm converges, i.e., when it finds the parameter combination that best matches the theoretical curve and the experimental curve, the fitting of the correction parameters is complete. At this point, the theoretical model is calibrated using this set of fitted parameters, becoming a corrected model that highly matches the actual physical state of the current specific microscope.

[0093] Example 7

[0094] Based on the above embodiments 1, 2, 3, 4, 5, and 6, as an optional implementation method, the system response efficiency of the microscope to be calibrated is determined using a modified theoretical model within the entire object-side field of view and the continuous spectral range, including:

[0095] Step 410: Input the position coordinates within the target object's field of view and the wavelength values ​​within the target's continuous spectral range into the corrected theoretical model. Based on practical application requirements, define the target object's field of view to be predicted, for example, a rectangular region with specific length and width dimensions centered on the optical axis. Discretize this region into a dense two-dimensional position coordinate grid, where each node represents a specific object point for which an efficiency value needs to be obtained. Simultaneously, determine the target's continuous spectral range, i.e., an interval from the lowest to the highest energy or wavelength. Discretize this spectral range into a series of wavelength points. Finally, combine all object position coordinates and all wavelength values ​​to form an input parameter list including all points to be determined in space and spectrum, and systematically input this list into the corrected theoretical model obtained in Example 6.

[0096] Step 420: Calculate and output the corresponding system response efficiency value using the corrected theoretical model, obtaining the system response efficiency distribution at any position within the target object's field of view and at any wavelength within the target's continuous spectral range in the microscope to be calibrated. After receiving the parameter list input in step 410, the corrected theoretical model will perform calculations for each combination. The calculation process includes determining the grazing incidence angle based on the calibrated geometric mapping relationship, calculating the corresponding reflectivity and light-gathering solid angle, and applying the calibrated intensity factor, ultimately outputting the corresponding system response efficiency value.

[0097] This embodiment combines the calibrated physical model with systematic parameter inputs to achieve global, continuous, and rapid calculation of the KB microscope system's response efficiency in both spatial and spectral dimensions. This generates high-precision, complete instrument response function data without the need for complex full-field-of-view, full-spectrum direct measurements, providing inputs that can be directly used for signal inversion and intensity correction for quantitative X-ray imaging diagnosis.

[0098] Example 8

[0099] Based on the above embodiments 1, 2, 3, 4, 5, 6 and 7, this embodiment details the specific experimental process of obtaining the measured value of the system response efficiency by measuring reflectivity. As an optional implementation method, the experimental measurement is divided into two stages.

[0100] In the first stage, a pinhole with a radius of 15 μm was placed in the object space to limit the size of the light source. The characteristic X-rays generated by the X-ray source passed through the pinhole and entered the KB microscope. After the image point positions were recorded on the image plane using an optical CCD, a Si-PIN spectral detector was placed in the image plane. Point, measuring the emitted spectrum In the second stage, the SDD was moved to point C on the line connecting the object point and the center of the mirror, and the incident spectrum was measured after removing the KB microscope. The reflectance of the KB microscope was obtained:

[0101]

[0102] In the formula, Indicates the position on the image plane The intensity of the emitted spectrum measured at the location; Indicates the position of the pinhole aperture in the object field of view. The solid angle subtended by the X-ray source at that location; Indicates the position in the object. The intensity of the incident spectrum obtained directly from the location; This indicates that the KB microscope is at the corresponding point. The theoretical light-gathering solid angle is determined. To obtain the variation of reflectance with the field of view, a high-precision displacement stage is needed to change the position of the pinhole on the object plane. For each new field of view coordinate point, the complete measurement and calculation process of the first and second stages described above is repeated. Typically, one-dimensional scans are performed along the horizontal and vertical directions defined by the microscope's optical axis to obtain a dataset of reflectance distribution within the two-dimensional field of view. Since the laboratory X-ray tube used produces characteristic radiation with quasi-monoenergetic spectral lines, the final reflectance distribution obtained is the spatial response function of the KB microscope for this single characteristic energy point.

[0103] Based on the experimental results, the reflectance distribution curve of the KB microscope as a function of the field of view was plotted. The theoretical model was used to calculate the reflectance distribution curve at this energy point, and the minimum mean square error was used to fit the grazing incidence angle at the center of the field of view. ) and intensity correction factor To make the theoretical results match the experimental results, such as Figure 3 As shown, the minimum mean square error (MSE) is 0.0003. The full-field, full-spectrum response efficiency of the KB microscope can be calculated using the corrected model, as follows: Figure 3 As shown, the response efficiency at any energy point can be calculated. This demonstrates the feasibility and effectiveness of the method framework constructed in the aforementioned embodiments.

[0104] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details of the invention described above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the specific details described above.

[0105] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0106] The block diagrams of devices, apparatuses, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0107] The methods and apparatus of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0108] It should also be noted that in the apparatus, device, and method of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of the present invention.

[0109] The above description of aspects of the invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features of the invention herein.

[0110] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms described herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

[0111] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0112] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for calibrating the full-field-of-view, full-spectrum response efficiency of a KB microscope, characterized in that, The method includes: Obtain the measured system response efficiency of the microscope to be calibrated at at least one selected position in the object-side field of view at at least one discrete energy point; A theoretical model of the system response efficiency of the microscope to be calibrated is constructed. This model characterizes the system response efficiency as a function of the object-side field-of-view position and the incident X-ray wavelength, and includes at least one correction parameter to characterize the deviation between the actual system and the ideal model, including: Calculate the product of the X-ray collecting solid angle of the microscope to be calibrated and its reflectivity. Calculate the reflectivity based on the product of the reflectivity of the front mirror and the reflectivity of the rear mirror in the microscope to be calibrated. Calculate the collecting solid angle based on the length of the mirrors, the object distance, and the grazing angle of incidence of the microscope to be calibrated. The system response efficiency is calculated based on the product and the magnification of the microscope to be calibrated. The measured system response efficiency is compared and fitted with the calculation results of the theoretical model under the same corresponding conditions to correct the correction parameters, thus obtaining the corrected theoretical model. The correction parameters include the grazing incidence angle parameter at the center of the field of view and an intensity correction factor. The grazing incidence angle parameter at the center of the field of view is used to adjust the position of the system response efficiency distribution curve on the field of view. The intensity correction factor, as a product factor, is used to adjust the intensity of the system response efficiency. The comparison and fitting of the measured system response efficiency with the calculation results of the theoretical model includes: Based on the measured system response efficiency at a single discrete energy point, a distribution curve of the measured efficiency as a function of the field of view position is generated. The theoretical model is used to calculate the theoretical value of the system response efficiency under the same discrete energy point and the same field of view position, and the theoretical calculation distribution curve is generated. Using the measured distribution curve as a benchmark, the values ​​of the correction parameters are iteratively adjusted to minimize the preset difference between the theoretically calculated distribution curve and the measured distribution curve, and the correction parameters are fitted. Using the modified theoretical model, the system response efficiency of the microscope to be calibrated is determined within the entire object field of view and the continuous spectral range.

2. The method for calibrating the full-field, full-spectrum response efficiency of a KB microscope as described in claim 1, characterized in that, Obtain measured values ​​of system response efficiency, including: A pinhole is placed on the object side of the microscope to be calibrated to limit the beam of X-rays emitted from the X-ray source, forming a point-like X-ray source at the selected object side field of view. At the image plane position of the microscope to be calibrated, the emitted spectral intensity at the image point obtained after imaging by the microscope to be calibrated is measured using the first spectral detector. In the object side of the microscope to be calibrated, the second spectral detector is placed on the line connecting the point X-ray source and the center of the mirror of the microscope to be calibrated, and the intensity of the incident spectrum when the microscope is not being calibrated is measured. Calculate the measured system response efficiency at the selected location based on the emitted and incident spectral intensities.

3. The method for calibrating the full-field, full-spectrum response efficiency of a KB microscope as described in claim 2, characterized in that, Obtaining measured values ​​of system response efficiency also includes: By changing the position of the pinhole on the object plane, the measured values ​​of the system response efficiency at multiple different selected positions of the microscope to be calibrated at at least one direction within the object field of view are obtained.

4. The method for calibrating the full-field, full-spectrum response efficiency of a KB microscope as described in claim 1, characterized in that, The preset difference metric is the minimum mean square error, root mean square error, or mean absolute error.

5. The method for calibrating the full-field, full-spectrum response efficiency of a KB microscope as described in claim 1, characterized in that, Using the modified theoretical model, the system response efficiency of the microscope to be calibrated was determined across the entire object-side field of view and the continuous spectral range, including: Input the target's position coordinates within its field of view and the wavelength values ​​within its continuous spectral range into the corrected theoretical model; The system response efficiency value is calculated and output from the modified theoretical model, thus obtaining the system response efficiency distribution at any position within the target object's field of view and at any wavelength within the continuous spectral range of the target in the microscope to be calibrated.

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