Crystal non-polarized light diffraction efficiency calibration method, calibration system and installation method thereof
By combining a calibration system and method for components such as synchrotron radiation sources and corrugated tubes with the Monte Carlo method, the problem of low accuracy in the calibration of diffraction efficiency of X-ray crystals under unpolarized light was solved, and high-precision calibration of multi-angle and arbitrary incident planes was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHWEST INST OF NUCLEAR TECH
- Filing Date
- 2026-01-13
- Publication Date
- 2026-04-17
AI Technical Summary
Existing technologies for X-ray crystal diffraction efficiency calibration have low accuracy for non-polarized light diffraction efficiency, especially when the polarization state of the light source is unknown.
A crystal unpolarized light diffraction efficiency calibration system and method are adopted. Using a synchrotron radiation source, a centered bellows, a slip-on flange, a crystal frame and a detector, the diffraction efficiency of unpolarized light is calculated by measuring the diffraction efficiency curves of two different incident planes and the Monte Carlo method. Multiple simulations are performed to evaluate the uncertainty.
It achieves high-precision diffraction efficiency calibration with multiple diffraction angles and arbitrary incident planes, reduces calibration uncertainty, and solves the calibration accuracy problem when the polarization state of the light source is unknown.
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Figure CN121878769A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of crystal diffraction efficiency calibration technology, specifically relating to a method, calibration system and installation method for calibrating the diffraction efficiency of unpolarized light in a crystal. Background Technology
[0002] In inertial confinement fusion experiments, X-ray parameter diagnostics of plasma radiation can provide crucial information about the state of the high-temperature, high-density plasma core region, such as target shape, density distribution, and hotspot temperature. This information is critical for understanding the physics of fusion target implosion, optimizing the drive source and target shape, and ultimately achieving ignition and high energy gain. Currently, plasma temperatures are concentrated in the tens to hundreds of eV range, while X-ray radiation energies are concentrated in the 100 eV-5 keV range. X-ray spectroscopic diagnostic methods for this energy range mainly include crystal spectrometry and grating diffraction. Crystal spectrometry, based on the Bragg diffraction principle, features high energy resolution, simple structure, and low cost, making it an indispensable core technology for precise X-ray spectroscopic diagnostics. Crystal diffraction efficiency is a key parameter for quantitatively measuring plasma radiation characteristics; therefore, research on crystal diffraction efficiency calibration techniques is of great significance for improving the accuracy of quantitative spectroscopic diagnostics.
[0003] Currently, research on crystal diffraction efficiency calibration techniques both domestically and internationally primarily utilizes X-ray tube sources or synchrotron radiation sources. X-ray tube sources generate X-rays through electron beam striking, which are then output as monoenergetic characteristic spectral lines of a metallic target (such as Cu / Cr) via secondary fluorescence. The monochromatic X-rays produced by this method are typically unpolarized radiation sources, and their energies are generally above 4 keV, limited by the metallic target and its characteristic spectrum. In contrast, synchrotron radiation sources offer advantages such as high brightness, continuously adjustable energy, high collimation, and high linear polarization, covering an energy range from 10 eV to tens of keV, making them ideal sources for X-ray parameter calibration. However, the polarization characteristics of the X-rays output from a synchrotron radiation source directly affect the calibration results of crystal diffraction efficiency.
[0004] In 2011, Yang Jiamin et al. rotated the crystal around the incident light axis and measured the diffraction efficiency in two mutually perpendicular directions of the incident plane (defined as the plane containing the incident and reflected light). They then calculated the average value to obtain the diffraction efficiency of unpolarized light.
[0005] This invention proposes a method and system for calibrating the diffraction efficiency of crystals under arbitrary polarization light. Compared with previous methods, it can effectively reduce uncertainty and solve the problem of accurate calibration of the diffraction efficiency of X-ray crystals under unknown polarization state of the light source. Summary of the Invention
[0006] To overcome the shortcomings of low accuracy in the calibration of non-polarized light diffraction efficiency, this invention proposes a method, calibration system, and installation method for calibrating the non-polarized light diffraction efficiency of crystals.
[0007] The technical solution adopted by this invention to solve its technical problem is:
[0008] A crystal unpolarized light diffraction efficiency calibration system includes a light source, a corrugated tube, a slip-on flange, a cavity, a crystal holder, a first detector, a second detector, and a galvanometer.
[0009] The light source is connected to the corrugated pipe in a concentric configuration.
[0010] The two ends of the slip-on flange are connected to the end of the corrugated pipe and the cavity, respectively, and the two ends of the slip-on flange can rotate at any angle relative to the corrugated pipe. The slip-on flange is used to adjust the crystal incident plane.
[0011] The crystal is located on the crystal frame inside the cavity, on the optical axis of the light source, and forms a certain angle with the optical axis.
[0012] The first detector is installed inside the cavity and is used to measure the crystal diffraction signal. The second detector is located in the crystal incident light path and is used to measure the crystal incident light signal; when measuring the crystal diffraction signal, the second detector is moved out of the crystal incident light path.
[0013] The ammeter is connected to the first detector and the second detector to record the current signals generated by the first detector and the second detector.
[0014] In the crystal unpolarized light diffraction efficiency calibration system described above, both the first detector and the second detector are photodiode detectors.
[0015] In the aforementioned crystal unpolarized light diffraction efficiency calibration system, the light source is a synchrotron radiation source that outputs X-rays with continuously adjustable energy, ranging from 80 eV to 5 keV. When the light source is installed in a center-to-center connection with the corrugated tube, the light source outputs white light.
[0016] In the aforementioned crystal unpolarized light diffraction efficiency calibration system, the cavity is provided with several first detector mounting positions, each corresponding to a different diffraction angle, for measuring diffraction signals at several diffraction angles.
[0017] A method for installing a crystal unpolarized light diffraction efficiency calibration system includes the following steps:
[0018] Step 1, adjust the first target and the second target.
[0019] The light source, the first target, and the second target are placed in sequence.
[0020] The light source outputs white light, and the end of the light source is sealed with a glass vacuum. The first and second targets are adjusted according to the optical axis of the white light until the center of the reticle of the first and second targets coincides with the optical axis.
[0021] The distance between the first target and the second target shall not be less than 1m.
[0022] Step 2, Adjust the laser theodolite
[0023] The laser theodolite is placed on the optical axis of the light source, and the light source, the first target, the second target, and the laser theodolite are placed in sequence.
[0024] Adjust the position of the laser theodolite so that the laser emitted by the laser theodolite simultaneously passes through the center of the first target reticle and the center of the second target reticle.
[0025] Step 3, adjust the corrugated tube.
[0026] The corrugated tube is installed at the end of the light source, the front end of the corrugated tube is connected to the end of the light source, a reflector is installed at the flange at the rear end of the corrugated tube, and a white board is placed in front of the laser theodolite.
[0027] Adjust the corrugated tube until the laser theodolite spot coincides with the center of the reflector and the reflected spot coincides with the laser theodolite's laser emission port, that is, the light source and the corrugated tube are connected in a centered manner.
[0028] The reflected light spot is displayed on the whiteboard.
[0029] A method for calibrating the diffraction efficiency of unpolarized light from a crystal includes the following steps:
[0030] Step 4: Place the crystal into the crystal unpolarized light diffraction efficiency calibration system
[0031] The crystal is placed on a crystal holder and forms a certain angle with the optical axis of the light source, which is the measurement angle.
[0032] Step 5, Plotting the diffraction efficiency curve
[0033] Set the energy range of the X-rays output by the light source, as well as the energy scan step size.
[0034] At each energy level of the X-rays emitted by the light source, the second detector moves into the optical path and measures the incident light signal from the crystal; when the second detector moves out of the optical path, the first detector measures the diffraction signal from the crystal. A galvanometer records the current signals generated by the first and second detectors.
[0035] The number of diffracted photons and the number of incident photons at different incident energies are obtained from the current signal recorded by the galvanometer.
[0036] Calculate the diffraction efficiency of the crystal at the measurement angle formed with the optical axis for each incident energy, and plot the diffraction efficiency curve at the measurement angle.
[0037] The diffraction efficiency at each incident energy is equal to the ratio of the number of diffracted photons to the number of incident photons at that incident energy.
[0038] Step 6: Plot the diffraction efficiency curve at the rotation angle.
[0039] The target chamber (9) is rotated around the incident light axis by a certain angle, and the diffraction efficiency curve corresponding to the rotation angle is plotted according to step 5.
[0040] Step 7: Calculate the crystal's unpolarized light diffraction efficiency.
[0041] The first measurement of angle β1 is calculated using the following formula:
[0042] (1)
[0043] In equation (1), γ is the crystal rotation angle after the first measurement, θ is the crystal diffraction angle, and C is the ratio of the diffraction efficiencies obtained from the two measurements before and after rotation.
[0044] The first measured angle β1 is calculated, and the first measured angle β1 is within [0,π].
[0045] Diffraction efficiency R under unpolarized light N The calculation formula is as follows:
[0046] (2)
[0047] In equation (2), R β1 This represents the diffraction efficiency obtained from the first measurement.
[0048] In the above-described crystal unpolarized light diffraction efficiency calibration method, in step 5, the energy scanning step size of the X-rays output by the light source is 1 eV.
[0049] The above-mentioned method for calibrating the diffraction efficiency of unpolarized light in crystals also includes:
[0050] The Monte Carlo method is used to establish a mathematical model, define the probability density function of the input quantity, perform distribution propagation by random sampling of the probability distribution, determine the probability density function of the output quantity, and obtain the estimated value, standard uncertainty, and coverage interval of the output quantity under a specified coverage probability, thus achieving the assessment of measurement uncertainty. The specific process is as follows:
[0051] Step 8, Parameter Setting
[0052] A mathematical model for calibrating the diffraction efficiency of a crystal under arbitrary polarization is established. Based on the on-site conditions of the incident light signal and diffraction signal measured before and after the measurement angle rotation, the crystal diffraction efficiency R, the source intensity signal value Q, and the galvanometer error I are set. eThe uncertainties of the first measurement angle β1, the crystal rotation angle γ after the first measurement, the crystal diffraction angle θ, the source strength signal value Q, the first measurement angle β1, the crystal rotation angle γ after the first measurement, and the crystal diffraction angle θ.
[0053] Step 9: Perform a single simulation of the calibration process and calculate the diffraction efficiency of the unpolarized light from the simulated crystal.
[0054] Based on the set parameters, the diffraction efficiency of the simulated crystal before and after the measurement angle rotation is calculated, and the non-polarized light diffraction efficiency of the simulated crystal is obtained.
[0055] Step 10: The calibration process is simulated several times to obtain the simulation uncertainty.
[0056] The calibration process is simulated several times until the set number of simulations is reached, and the simulation results conform to a normal distribution. The standard deviation s of the simulation results is calculated, and the uncertainty is 2s.
[0057] The above-mentioned crystal unpolarized light diffraction efficiency calibration method, step 9, further includes:
[0058] The first step is to randomly generate the first measurement angle β based on β1 and its uncertainty. 10 Based on θ and its uncertainty, randomly generate the diffraction angle θ0; and set β... 10 Substituting θ0 into the following formula, the polarization factor P1 of the first measurement is calculated:
[0059]
[0060] The second step is to randomly generate a source strength signal Q0 based on Q and its uncertainty, and then couple the galvanometer measurement error I. e The source strength signal measurement value I0 is obtained;
[0061] The third step is to randomly generate the source strength signal Q0 again, multiply it by the true diffraction efficiency R and polarization factor P, and then couple it with the galvanometer measurement error I. e The diffraction signal measurement value I1 is obtained;
[0062] The fourth step is to use the signal measurement values obtained in the second and third steps to calculate the diffraction efficiency measurement value R1, which is calculated as: R1=I1 / I0;
[0063] Fifth step, repeat steps one through four, randomly generate the second measurement angle β2, and obtain the diffraction efficiency measurement value R2 at the second measurement angle β2;
[0064] Step 6: Calculate the first measured angle β1:
[0065] Substituting γ=β2-β1, θ, and C=R1 / R2 into formula (1), the first measured angle β1 is calculated.
[0066] Step 7: Substitute the obtained first measurement angle β1 into formula (2) to obtain the crystal unpolarized light diffraction efficiency R. N .
[0067] In the above-described method for calibrating the diffraction efficiency of unpolarized light in crystals, step 10 involves simulating at least 1E6 times.
[0068] The beneficial effects of this invention are:
[0069] A crystal nonpolarized light diffraction efficiency calibration system is disclosed, which can realize crystal diffraction efficiency calibration at multiple diffraction angles and arbitrary incident planes. The system achieves crystal diffraction efficiency calibration at multiple diffraction angles and arbitrary incident planes through a lightweight structure, which separates the centering structure, incident plane adjustment structure, crystal mounting structure and detector mounting structure, and ensures the reliability of calibration angles through high-precision machining.
[0070] A method for calibrating the diffraction efficiency of a crystal unpolarized light is proposed. This method enables the calibration of crystal diffraction efficiency at multiple diffraction angles and arbitrary incident planes through a single alignment, solving the problems of limited functionality and complex alignment processes in existing calibration systems.
[0071] A method for calibrating the diffraction efficiency of unpolarized light in a crystal is proposed. Based on the diffraction efficiency curves obtained from two different incident planes by measuring a synchrotron radiation source, the diffraction efficiency of unpolarized light is calculated by using the ratio of the diffraction efficiencies of the two measurements, the angle between the two incident planes, and the crystal diffraction angle. This method solves the problem that existing calibration methods can only obtain the diffraction efficiency of unpolarized light by averaging the results of two measurements with perpendicular incident planes.
[0072] A method for calibrating the diffraction efficiency of unpolarized light in crystals is proposed. Based on the Monte Carlo method, the input parameters are set according to the actual measurement conditions, and multiple simulations are performed to give the calibration uncertainty, which solves the problem that existing calibration methods are difficult to analyze the system uncertainty.
[0073] A method for calibrating the diffraction efficiency of unpolarized light from a crystal is proposed, which measures the diffraction efficiency of unpolarized light from the crystal when the polarization characteristics of the light source are unknown. This solves the problem of low accuracy in calibrating the unpolarized light diffraction efficiency of X-ray crystals when the polarization state of the light source is unknown. Attached Figure Description
[0074] Figure 1 This is a schematic diagram of the alignment process between the light source and the corrugated tube in Embodiment 1 of the present invention, wherein, Figure 1 -a represents the target establishment process. Figure 1 -b represents the optical axis reproduction process. Figure 1 -c represents the bellows adjustment process;
[0075] Figure 2This is a schematic diagram of the diffraction efficiency calibration system according to Embodiment 1 of the present invention.
[0076] The attached figures are labeled as follows:
[0077] 1. Light source, 2. First target, 3. Second target, 4. Laser theodolite, 5. Corrugated pipe, 6. Mirror, 7. Whiteboard, 8. Loose flange, 9. Cavity, 10. Crystal frame, 11. First detector, 12. Second detector, 13. Ammeter. Detailed Implementation
[0078] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0079] Example 1
[0080] A crystal diffraction efficiency calibration system capable of achieving multiple diffraction angles and arbitrary incident planes, and a method for accurately calibrating the diffraction efficiency of unpolarized light under arbitrary polarization, are disclosed. The calibration system consists of a centered bellows, a slip-on flange, a crystal, and a detector mounting cavity. Its key features include using the centered bellows for alignment, adjusting the incident plane using the slip-on flange, and adjusting the crystal mounting angle using a crystal holder while reserving multiple detector mounting positions to achieve crystal diffraction efficiency measurements at multiple diffraction angles. The calibration method, based on a synchrotron radiation source and the aforementioned calibration system, calculates the diffraction efficiency of unpolarized light by measuring the diffraction efficiency curves under two different incident planes, and then provides the calibration uncertainty based on the Monte Carlo method.
[0081] The crystal diffraction efficiency calibration system capable of achieving multiple diffraction angles and arbitrary incident planes consists of a light source 1, a target, a laser theodolite 4, a aligning bellows 5, a reflector 6, a white board 7, a slip-on flange 8, a cavity 9, a crystal holder 10, a detector, and a galvanometer 13. The target includes a first target 2 and a second target 3, and the detector includes a first detector 11 and a second detector 12.
[0082] Light source 1 refers to a synchrotron radiation source, which is a source capable of outputting X-rays within a certain energy range, typically from tens of eV to several keV. The output energy is continuously adjustable and can also output white light for centering.
[0083] The target is used for optical axis reproduction and consists of an adjustment device and a reticle. The center of the reticle is positioned on the optical axis by adjustment, and the distance between the two targets is generally not less than 1m.
[0084] The laser theodolite 4 is used to establish the optical axis, and by adjustment, the emitted laser is made to pass exactly through the center of the two target differentiation plates.
[0085] The corrugated pipe 5, the reflector 6, and the white board 7 are used for alignment. The reflector is parallel and concentric with the flange face at the end of the corrugated pipe 5. The crosshairs on the reflector indicate the center position, and the white board is used to indicate the position of the reflected light spot.
[0086] The alignment process refers to adjusting the alignment bellows 5 so that the light spot of the laser theodolite 4 coincides with the center of the reflector 6, and the reflected light spot coincides with the laser emission port of the laser theodolite 4. At this time, the rear end face of the alignment bellows 5 is concentric and perpendicular to the optical axis.
[0087] The flanges at both ends of the slip-on flange 8 can rotate at any angle relative to the corrugated pipe.
[0088] The cavity 9 is used to install the crystal and detector, and its relative positional relationship is ensured by precision machining.
[0089] The crystal holder 10 is precisely fitted with the cavity, and multiple crystal holders are fabricated to meet the measurement requirements of crystal diffraction efficiency at different diffraction angles.
[0090] The first detector 11 refers to a photodiode detector, which is used to record crystal diffraction signals. Multiple detector installation positions are reserved on the cavity to correspond to different crystal diffraction angles.
[0091] The second detector 12 is used to record the incident light signal. It can move in a direction perpendicular to the optical axis. When measuring the incident signal, it moves into the optical path, and when measuring the diffraction signal, it moves out of the optical path.
[0092] The ammeter 13 is used to record the current signal generated by the detector.
[0093] The method for accurately calibrating the diffraction efficiency of unpolarized light in a crystal under arbitrary polarization includes two steps. The first step is to obtain diffraction efficiency curves with two different incident planes based on measurements from a synchrotron radiation source. The diffraction efficiency of the unpolarized light is calculated using the ratio of the diffraction efficiencies of the two measurements, the angle between the two incident planes, and the crystal diffraction angle. The second step is to use the Monte Carlo method to set input parameters according to the actual measurement conditions and perform multiple simulations to give the calibration uncertainty.
[0094] The first step is:
[0095] The synchrotron radiation source can output X-rays with a certain energy range, typically from tens of eV to several keV, and the output energy is continuously adjustable; the diffraction efficiency curve describes the diffraction characteristics of the crystal for X-rays and obeys Bragg's diffraction law.
[0096] The measurement of the crystal diffraction efficiency curve refers to the process of measuring the incident signal and the diffraction signal using a photodiode detector during the energy scanning process, and recording the output current of the photodiode detector using a small ammeter; then, based on the relative sensitivity of the two detectors, the ratio of the number of diffracted photons to the number of incident photons under different incident energies is calculated, which is the measured diffraction efficiency curve of the crystal.
[0097] The incident plane refers to the plane determined by the incident light path and the diffraction light path; the two different incident planes refer to the second measurement performed after the first measurement, when the crystal is rotated around the incident light axis by a certain angle.
[0098] The calculated non-polarized light diffraction efficiency refers to β1 first calculated using the following formula:
[0099]
[0100] Where γ is the crystal rotation angle after the first measurement, θ is the crystal diffraction angle, and C is the ratio of the diffraction efficiencies obtained from the two measurements. β1 is calculated in the range [0,π], and then the diffraction efficiency R under unpolarized light is calculated using the following formula. N :
[0101]
[0102] Rβ1 represents the diffraction efficiency obtained from the first measurement.
[0103] The second step is:
[0104] The Monte Carlo method refers to determining the probability density function of the output quantity by randomly sampling and propagating the probability distribution based on a mathematical model and setting the probability density function of the input quantity. This yields the estimated value, standard uncertainty, and coverage interval of the output quantity under a specified coverage probability, thereby enabling the assessment of measurement uncertainty.
[0105] The actual measurement conditions refer to determining the crystal diffraction efficiency R, source strength signal value Q, and galvanometer error I based on the experimental site conditions. e The uncertainties of the first measurement angle β1, the crystal rotation angle γ after the first measurement, the crystal diffraction angle θ, and Q, β1, γ, and θ.
[0106] The single simulation process includes:
[0107] (1) Based on β1 and its uncertainty, the first measurement angle β is randomly generated. 10 Based on θ and its uncertainty, randomly generate the diffraction angle θ0; and set β... 10 Substituting θ0 into the following formula, the polarization factor P1 of the first measurement is calculated:
[0108]
[0109] (2) Based on Q and its uncertainty, a source strength signal Q0 is randomly generated, and the measurement error I of the coupled galvanometer is... e The source strength signal measurement value I0 is obtained;
[0110] (3) Randomly generate the source strength signal Q0 again, multiply it by the true diffraction efficiency R and polarization factor P, and then couple it to the galvanometer measurement error I. e The diffraction signal measurement value I1 is obtained;
[0111] (4) Using the signal measurement values obtained in the second and third steps, calculate the diffraction efficiency measurement value R1. The calculation formula is: R1=I1 / I0;
[0112] (5) Repeat steps one through four to randomly generate the second measurement angle β2 and obtain the diffraction efficiency measurement value R2 at the second measurement angle β2;
[0113] (6) Calculate the first measured angle β1:
[0114] Substituting γ=β2-β1, θ, and C=R1 / R2 into formula (1), the first measured angle β1 is calculated.
[0115] (7) Substitute the obtained first measurement angle β1 into formula (2) to obtain the crystal unpolarized light diffraction efficiency R. N .
[0116] The term "performing multiple simulations" generally refers to performing no fewer than 1E6 simulations, with the results conforming to a normal distribution. The term "giving the calibration uncertainty" refers to calculating the standard deviation s of all simulation results, with an uncertainty of 2s (k=2, indicating that the confidence interval is twice the standard deviation).
[0117] A method and system for accurately calibrating the diffraction efficiency of a crystal under arbitrary polarized light includes the following steps:
[0118] 1) Figure 1 This is a schematic diagram of the cardiac process, such as Figure 1 As shown in -a, the synchrotron radiation source is adjusted to white light mode, and the end of the source is sealed with a glass vacuum. The two targets are adjusted according to the white light optical axis so that the center of the reticle on the target coincides with the optical axis.
[0119] 2) such as Figure 1 As shown in -b, a laser theodolite is set up behind the two targets, and the laser theodolite is adjusted so that the emitted laser passes through the two targets;
[0120] 3) such as Figure 1 As shown in -c, install the corrugated tube at the end of the light source and install a reflector at the flange at the rear end of the corrugated tube. Observe the position of the reflected light spot through the white board. Adjust the corrugated tube so that the laser theodolite spot coincides with the center of the reflector and the reflected light spot coincides with the laser emission port of the laser theodolite. At this time, the rear end face of the corrugated tube is concentric and perpendicular to the optical axis.
[0121] 4) such as Figure 2The installation and calibration system is shown as follows: The loose flange is installed at the end of the corrugated pipe, and the cavity is installed at the end of the loose flange. The crystal holder containing the crystal and the detector are installed in the cavity. The detector signal is transmitted to the ammeter for recording through the signal cable.
[0122] 5) Set the scanning range according to the peak energy of the crystal. The step size is generally set to 1eV. At each energy, first move the front detector of the target chamber into the optical path to record the incident light signal, then move the detector out of the optical path and use the end detector of the target chamber to record the diffraction signal. After normalizing the relative sensitivity of the two detectors, calculate the ratio of the diffraction signal to the source intensity signal to obtain the diffraction efficiency curve of the crystal.
[0123] 6) Rotate the target chamber (including crystal, end detector, etc.) around the incident optical axis by a certain angle, and repeat step 5) to obtain the diffraction efficiency curve after the rotation angle;
[0124] 7) Calculate the diffraction efficiency under unpolarized light using the results of the two measurements:
[0125] First, β1 is calculated using the following formula:
[0126]
[0127] Where γ is the crystal rotation angle after the first measurement, θ is the crystal diffraction angle, and C is the ratio of the diffraction efficiencies obtained from the two measurements. β1 is calculated in the range [0,π], and then the diffraction efficiency RN under unpolarized light is calculated using the following formula:
[0128]
[0129] Rβ1 represents the diffraction efficiency obtained from the first measurement.
[0130] 8) Based on the experimental conditions, determine the crystal diffraction efficiency, source strength signal value, galvanometer error, first measurement angle β1, crystal rotation angle γ after the first measurement, crystal diffraction angle θ, and the uncertainties of β1, γ, and θ.
[0131] 9) Simulate the measurement process, including:
[0132] Generate the first measurement angle β1 and diffraction angle θ, and calculate the polarization factor. ; Generate source strength signal Q, couple the galvanometer measurement error to obtain source strength signal measurement value I0; Generate source strength signal Q, multiply by the true diffraction efficiency, multiply by the polarization factor, and then couple the galvanometer measurement error to obtain diffraction signal measurement value I1; Diffraction efficiency measurement value R1=I1 / I0; Repeat steps (1)~(4) to obtain diffraction efficiency measurement value R2 when the measurement angle is β2; Substitute γ=β2-β1, θ, C=R1 / R2 into the formula to calculate β1; Substitute the obtained β1 into the formula to obtain the diffraction efficiency RN under unpolarized light.
[0133] 10) Perform multiple simulations of the measurement process, generally no less than 1E6 times. The results conform to a normal distribution. Calculate the standard deviation s of all simulation results. The uncertainty is 2s (k=2).
Claims
1. A crystal unpolarized light diffraction efficiency calibration system, characterized in that, Includes a light source (1), a corrugated pipe (5), a slip-on flange (8), a cavity (9), a crystal holder (10), a first detector (11), a second detector (12), and a galvanometer (13); The light source (1) is centeredly connected to the corrugated pipe (5); The two ends of the slip-on flange (8) are connected to the end of the corrugated pipe (5) and the cavity (9) respectively. The two ends of the slip-on flange (8) can rotate at any angle relative to the corrugated pipe (5). The slip-on flange (8) is used to adjust the crystal incident plane. The crystal is located on the crystal frame (10) inside the cavity (9) and on the optical axis of the light source (1), forming a certain angle with the optical axis; The first detector (11) is installed inside the cavity (9) and is used to measure the crystal diffraction signal; the second detector (12) is located on the crystal incident light path and is used to measure the crystal incident light signal; when measuring the crystal diffraction signal, the second detector (12) is moved out of the crystal incident light path; The ammeter (13) is connected to the first detector (11) and the second detector (12) to record the current signals generated by the first detector (11) and the second detector (12).
2. The crystal unpolarized light diffraction efficiency calibration system according to claim 1, characterized in that, Both the first detector (11) and the second detector (12) are photodiode detectors.
3. The crystal unpolarized light diffraction efficiency calibration system according to claim 1, characterized in that, The light source (1) is a synchrotron radiation source that outputs X-rays with continuously adjustable energy. The output X-ray energy range is 80eV to 5keV. When the light source (1) is installed in a symmetrical connection with the corrugated tube (5), the light source (1) outputs white light.
4. The crystal unpolarized light diffraction efficiency calibration system according to claim 1, characterized in that, The cavity (9) is provided with several first detector (11) mounting positions, each corresponding to a different diffraction angle, for measuring diffraction signals at several diffraction angles.
5. A method for installing a crystal unpolarized light diffraction efficiency calibration system according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1, adjust the first target and the second target: The light source (1), the first target (2), and the second target (3) are placed in sequence; The light source (1) outputs white light. The end of the light source (1) is sealed with glass to create a vacuum. The first target (2) and the second target (3) are adjusted according to the optical axis of the white light until the center of the reticle of the first target (2) and the second target (3) coincides with the optical axis. The distance between the first target (2) and the second target (3) is not less than 1m; Step 2, adjust the laser theodolite: The laser theodolite (4) is placed on the optical axis of the light source (1), and the light source (1), the first target (2), the second target (3), and the laser theodolite (4) are placed in sequence. Adjust the position of the laser theodolite (4) so that the laser emitted by the laser theodolite (4) passes through the center of the first target (2) reticle and the center of the second target (3) reticle simultaneously; Step 3, adjust the corrugated tube: The corrugated tube (5) is installed at the end of the light source (1), the front end of the corrugated tube (5) is connected to the end of the light source (1), a reflector (6) is installed at the flange of the rear end of the corrugated tube (5), and a white board (7) is placed in front of the laser theodolite (4). Adjust the corrugated tube (5) until the center of the laser theodolite (4) coincides with the center of the reflector (6) and the reflected light spot coincides with the laser emission port of the laser theodolite (4), that is, the light source (1) and the corrugated tube (5) are connected in a centered manner. The reflected light spot is displayed on the whiteboard (7).
6. A method for calibrating the diffraction efficiency of unpolarized light from a crystal, using the crystal unpolarized diffraction efficiency calibration system of any one of claims 1-4, characterized in that, Includes the following steps: Step 4: Place the crystal into the crystal unpolarized light diffraction efficiency calibration system. The crystal is placed on the crystal holder (10) and forms a certain angle with the optical axis of the light source (1), which is the measurement angle; Step 5, Plot the diffraction efficiency curve: Set the energy range of the X-rays output by the light source (1) and the energy scan step size; At each energy level of the X-rays output by the light source (1), the second detector (12) moves into the optical path and measures the incident light signal of the crystal; the second detector (12) moves out of the optical path and the first detector (11) measures the diffraction signal of the crystal; the galvanometer (13) records the current signals generated by the first detector (11) and the second detector (12); The number of diffracted photons and the number of incident photons under different incident energies are obtained from the current signal recorded by the galvanometer (13). Calculate the diffraction efficiency of the crystal at each incident energy at the measurement angle formed with the optical axis, and plot the diffraction efficiency curve at the measurement angle; The diffraction efficiency at each incident energy is equal to the ratio of the number of diffracted photons to the number of incident photons at that incident energy. Step 6, Plot the diffraction efficiency curve by rotation angle: Rotate the target chamber (9) around the incident optical axis by a certain angle, repeat step 5, and draw the diffraction efficiency curve corresponding to the rotation angle; Step 7, calculate the diffraction efficiency of unpolarized light from the crystal: The first measurement of angle β1 is calculated using the following formula: ； （1） In equation (1), γ is the crystal rotation angle after the first measurement, θ is the crystal diffraction angle, and C is the ratio of the diffraction efficiencies obtained from the two measurements before and after rotation. The first measured angle β1 is calculated, and the first measured angle β1 is within [0,π]. Diffraction efficiency R under unpolarized light N The calculation formula is as follows: ； （2） In equation (2), R β1 This represents the diffraction efficiency obtained from the first measurement.
7. The method for calibrating the diffraction efficiency of unpolarized light in a crystal according to claim 6, characterized in that, In step 5, the energy scanning step of the X-rays output by the light source (1) is 1eV.
8. The method for calibrating the diffraction efficiency of unpolarized light in a crystal according to claim 6, characterized in that, Also includes: The Monte Carlo method is used to establish a mathematical model, define the probability density function of the input quantity, perform distribution propagation by random sampling of the probability distribution, determine the probability density function of the output quantity, and obtain the estimated value, standard uncertainty, and coverage interval of the output quantity under a specified coverage probability, thereby achieving the evaluation of measurement uncertainty. The specific process is as follows: Step 8, Parameter Settings: A mathematical model for calibrating the diffraction efficiency of a crystal under arbitrary polarization is established. Based on the on-site conditions of the incident light signal and diffraction signal measured before and after the measurement angle rotation, the crystal diffraction efficiency R, the source intensity signal value Q, and the galvanometer error I are set. e The uncertainties of the first measurement angle β1, the crystal rotation angle γ after the first measurement, the crystal diffraction angle θ, the source strength signal value Q, the first measurement angle β1, the crystal rotation angle γ after the first measurement, and the crystal diffraction angle θ; Step 9: Perform a single simulation of the calibration process and calculate the diffraction efficiency of the unpolarized light from the simulated crystal. Based on the set parameters, the diffraction efficiency of the simulated crystal before and after the measurement angle rotation is calculated, and the non-polarized light diffraction efficiency of the simulated crystal is obtained. Step 10: The calibration process is simulated several times to obtain the simulation uncertainty. The calibration process is simulated several times until the set number of simulations is reached, and the simulation results conform to a normal distribution. The standard deviation s of the simulation results is calculated, and the uncertainty is 2s.
9. The method for calibrating the diffraction efficiency of unpolarized light in a crystal according to claim 8, characterized in that, Step 9 further includes: The first step is to randomly generate the first measurement angle β based on β1 and its uncertainty. 10 Based on θ and its uncertainty, randomly generate the diffraction angle θ0; and set β... 10 Substituting θ0 into the following formula, the polarization factor P1 of the first measurement is calculated: ； The second step is to randomly generate a source strength signal Q0 based on Q and its uncertainty, and then couple the galvanometer measurement error I. e The source strength signal measurement value I0 is obtained; The third step is to randomly generate the source strength signal Q0 again, multiply it by the true diffraction efficiency R and polarization factor P, and then couple it with the galvanometer measurement error I. e The diffraction signal measurement value I1 is obtained; The fourth step is to use the signal measurement values obtained in the second and third steps to calculate the diffraction efficiency measurement value R1, which is calculated as: R1=I1 / I0; Fifth step, repeat steps one through four, randomly generate the second measurement angle β2, and obtain the diffraction efficiency measurement value R2 at the second measurement angle β2; Step 6: Calculate the first measured angle β1: Substituting γ=β2-β1, θ, and C=R1 / R2 into formula (1), the first measured angle β1 is calculated. Step 7: Substitute the obtained first measurement angle β1 into formula (2) to obtain the crystal unpolarized light diffraction efficiency R. N .
10. The method for calibrating the diffraction efficiency of unpolarized light in a crystal according to claim 8, characterized in that, In step 10, the simulation is set to be no less than 1E6 times.