Energy calibration method of X-ray absorption spectrum

Abstract

The invention relates to an energy calibration method for an X-ray absorption spectrum, and the method comprises the steps: providing an X-ray absorption spectrometer which comprises a monochromator, a first ionization chamber and a second ionization chamber; performing an X-ray absorption spectrum experiment on the to-be-tested sample to obtain a change curve of the absorption coefficient of the to-be-tested sample along with the angle of the monochromator and a change curve of the intensity of the X-ray measured by the corresponding first ionization chamber along with the angle of the monochromator; determining a monochromator angle at a monochromator crystal Glitch point; determining the energy of monochromatic light corresponding to a monochromator angle at a monochromator crystal Glitch point of the sample to be detected; determining a Bragg angle at a Glitch point of the monochromator; the mapping relation between the monochromator angle and the Bragg angle of the sample to be measured; determining the corresponding relation between the monochromator angle of the sample to be detected and the energy of the monochromatic light; and converting the change curve of the absorption coefficient of the to-be-detected sample along with the angle of the monochromator into the change curve of the absorption coefficient of the to-be-detected sample along with the energy of the monochromatic light.

Description

Technical Field

[0001] The present invention relates to the technical field of X-ray absorption spectroscopy, and more particularly to an energy calibration method for X-ray absorption spectroscopy. Background Art

[0002] In QXAFS (Quick X-ray Absorption Fine Structure) experiments, the rapid oscillatory motion of the monochromator crystal causes angular deviation, which in turn leads to energy drift. Therefore, it is necessary to perform real-time energy calibration and scale of the monochromator angle.

[0003] In the prior art, the "three ionization chambers" method is usually used to calibrate the energy of X-ray absorption spectroscopy. It includes three ionization chambers arranged in sequence. The first ionization chamber and the second ionization chamber are placed with the sample to be measured, and a standard sample is set between the second ionization chamber and the third ionization chamber, so as to calibrate the energy of the X-ray absorption spectrum of the sample to be measured.

[0004] However, the existing "three ionization chambers" method requires an additional ionization chamber and a standard sample, resulting in an increase in both the experimental complexity and cost. Summary of the Invention

[0005] The purpose of the present invention is to provide an energy calibration method for X-ray absorption spectroscopy, which can achieve energy calibration without adding additional equipment, thereby reducing the experimental complexity and cost.

[0006] Based on the above purpose, the present invention provides an energy calibration method for X-ray absorption spectroscopy, which includes the following steps:

[0007] S100: Provide an X-ray absorption spectrometer, including a monochromator, a first ionization chamber, and a second ionization chamber arranged in sequence along the X-ray transmission direction;

[0008] S200: Place the sample to be measured between the first ionization chamber and the second ionization chamber, and perform an X-ray absorption spectroscopy experiment on the sample to be measured to obtain a curve of the absorption coefficient of the sample to be measured changing with the monochromator angle and a curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the sample to be measured changing with the monochromator angle;

[0009] S300: Determine the monochromator angle at the Glitch point of the monochromator crystal according to the curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the sample to be measured changing with the monochromator angle;

[0010] S400: Based on the pre-acquired energy database of the Glitch point of the monochromator crystal, determine the energy of the monochromatic light corresponding to the monochromator angle at the Glitch point of the monochromator crystal of the sample to be measured;

[0011] S500: Determine the Bragg angle at the Glitch point of the monochromator crystal based on the energy of the monochromatic light corresponding to the monochromator angle at the Glitch point of the monochromator crystal for the sample to be measured and the Bragg formula;

[0012] S600: Determine the mapping relationship between the monochromator angle and the Bragg angle for the sample to be measured based on the monochromator angle and the Bragg angle at the Glitch point of the monochromator crystal, and use it as the first mapping relationship;

[0013] S700: Determine the corresponding relationship between the monochromator angle and the energy of the monochromatic light for the sample to be measured based on the Bragg formula and the first mapping relationship;

[0014] S800: Based on the corresponding relationship between the monochromator angle and the energy of the monochromatic light for the sample to be measured, convert the curve of the absorption coefficient of the sample to be measured varying with the monochromator angle into the curve of the absorption coefficient of the sample to be measured varying with the energy of the monochromatic light.

[0015] Optionally, step S300 specifically includes:

[0016] Obtain the trough in the curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the sample to be measured varying with the monochromator angle as the Glitch point of the monochromator crystal;

[0017] Obtain the monochromator angle corresponding to the trough as the monochromator angle at the Glitch point of the monochromator crystal.

[0018] Optionally, step S600 specifically includes:

[0019] Obtain the difference between the Bragg angle and the monochromator angle at the Glitch point of the monochromator crystal as the first deviation;

[0020] Determine the Bragg angle corresponding to each monochromator angle of the sample to be measured according to the first deviation.

[0021] Optionally, step S800 specifically includes:

[0022] According to the corresponding relationship between the monochromator angle and the energy of the monochromatic light for the sample to be measured, obtain the energy of the monochromatic light corresponding to each monochromator angle in the curve of the absorption coefficient of the sample to be measured varying with the monochromator angle;

[0023] Replace each monochromator angle with the energy of the monochromatic light corresponding to the monochromator angle to obtain the curve of the absorption coefficient of the sample to be measured varying with the energy of the monochromatic light.

[0024] Optionally, the energy database of the monochromator Glitch points includes the monochromator Glitch points and the energies of the monochromatic lights corresponding to the monochromator Glitch points.

[0025] Optionally, the energy database of the monochromator Glitch points is obtained by pre-measurement, and the measurement method includes:

[0026] Place a standard sample between the first ionization chamber and the second ionization chamber, and perform an X-ray absorption spectrum experiment on the standard sample to obtain the curve of the absorption coefficient of the standard sample varying with the monochromator angle and the curve of the intensity of the X-rays measured by the first ionization chamber corresponding to the standard sample varying with the monochromator angle; wherein, the X-ray absorption spectrum of the standard sample has significant near-edge characteristic peaks, and the energy of the monochromatic light corresponding to the near-edge characteristic peaks is a fixed value;

[0027] Based on the curve of the absorption coefficient of the standard sample varying with the monochromator angle and the energy of the monochromatic light corresponding to the near-edge characteristic peaks, determine the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the standard sample;

[0028] Based on the curve of the intensity of the X-rays measured by the first ionization chamber corresponding to the standard sample varying with the monochromator angle, determine the monochromator crystal Glitch points and the monochromator angles at the monochromator crystal Glitch points;

[0029] According to the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the standard sample, determine the energy of the monochromatic light at the monochromator crystal Glitch points.

[0030] Optionally, based on the curve of the absorption coefficient of the standard sample varying with the monochromator angle and the energy of the monochromatic light corresponding to the near-edge characteristic peaks, determining the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the standard sample specifically includes:

[0031] Obtain the monochromator angle at the peak of the curve of the absorption coefficient of the standard sample varying with the monochromator angle as the monochromator angle of the near-edge characteristic peak;

[0032] Based on the energy of the monochromatic light corresponding to the near-edge characteristic peak, determine the Bragg angle corresponding to the near-edge characteristic peak;

[0033] Obtain the difference between the Bragg angle of the near-edge characteristic peak and the monochromator angle of the near-edge characteristic peak as the second deviation;

[0034] Based on the second deviation, determine the Bragg angle corresponding to each monochromator angle of the standard sample;

[0035] Determine the energy of the monochromatic light corresponding to the monochromator angle based on the Bragg angle corresponding to each monochromator angle and the Bragg formula.

[0036] Optionally, the relationship between the Bragg angle and the energy of the monochromatic light is:

[0037] ,

[0038] where θ is the Bragg angle of the monochromator crystal, h is Planck's constant, c is the speed of light, d is the lattice plane spacing of the monochromator crystal, and E is the energy of the monochromatic light.

[0039] The energy calibration method of the X-ray absorption spectrum of the present invention realizes real-time energy calibration based on the Glitch phenomenon of the monochromator crystal, without the need to add additional equipment, can significantly reduce the experimental complexity and cost, and the calibration accuracy can reach ±0.1 eV, meeting the requirements of high-precision experiments. Brief Description of the Drawings

[0040] Figure 1 is a flowchart of the energy calibration method of the X-ray absorption spectrum according to an embodiment of the present invention;

[0041] Figure 2 is a schematic structural diagram of an X-ray absorption spectrometer according to an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of the change curve of the absorption coefficient of zinc foil with the monochromator angle according to an embodiment of the present invention;

[0043] Figure 4 is a schematic diagram of the change curve of the intensity of X-rays measured by the first ionization chamber corresponding to zinc foil with the monochromator angle according to an embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of the change curve of the absorption coefficient of zinc foil with the energy of the monochromatic light according to an embodiment of the present invention;

[0045] Figure 6 is a schematic diagram of the change curve of the intensity of X-rays measured by the first ionization chamber corresponding to zinc foil with the energy of the monochromatic light according to an embodiment of the present invention;

[0046] Figure 7 is a schematic diagram of the change curve of the absorption coefficient of zinc oxide with the monochromator angle according to an embodiment of the present invention;

[0047] Figure 8 is a schematic diagram of the change curve of the intensity of X-rays measured by the first ionization chamber corresponding to zinc oxide with the monochromator angle according to an embodiment of the present invention;

[0048] Figure 9Schematic diagram of the variation curve of the absorption coefficient of zinc oxide with the energy of monochromatic light according to an embodiment of the present invention. Detailed implementation manners

[0049] The following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0050] As Figure 1 shown, an embodiment of the present invention provides an energy calibration method for X-ray absorption spectra, which includes the following steps:

[0051] S100: Provide an X-ray absorption spectrometer. As Figure 2 shown, the X-ray absorption spectrometer includes a monochromator 10, a first ionization chamber 20, and a second ionization chamber 30 arranged in sequence along the X-ray transmission direction.

[0052] The monochromator 10 is used to convert the X-rays emitted by the X-ray source into monochromatic light, and the first ionization chamber 20 and the second ionization chamber 30 are used to obtain the intensity of the X-rays incident thereon.

[0053] S200: Place the sample to be measured 40 between the first ionization chamber 20 and the second ionization chamber 30, and perform an X-ray absorption spectrum experiment on the sample to be measured 40 to obtain the variation curve of the absorption coefficient of the sample to be measured 40 with the monochromator angle and the variation curve of the intensity of the X-rays measured by the first ionization chamber 20 corresponding to the sample to be measured 40 with the monochromator angle.

[0054] When performing an X-ray absorption spectrum experiment on the sample to be measured 40 using the X-ray absorption spectrometer, after the X-rays emitted by the X-ray source pass through the monochromator 10, the monochromator 10 will convert them into monochromatic light. The monochromatic light passes through the first ionization chamber 20, the sample to be measured 40, and the second ionization chamber 30 in sequence. The first ionization chamber 20 is used to measure the intensity of the monochromatic light, and the second ionization chamber 30 is used to measure the intensity of the monochromatic light after passing through the sample to be measured 40. During the experiment, the monochromator angle is continuously adjusted. At each monochromator angle, the first ionization chamber 20 and the second ionization chamber 30 will measure an intensity signal. Assume that the monochromator angle is θ i , i is the serial number of the monochromator angle, i = 1, 2... n, and n is the number of monochromator angles; at the angle θ i , the intensity of the monochromatic light measured by the first ionization chamber 20 is I 1,θi , and the monochromatic light I 2,θi measured by the second ionization chamber 30 after passing through the sample to be measured 40. According to I 1,θi and I 2,θi , the absorption coefficient μ i of the sample to be measured 40 at the angle θ i can be obtained, where μ i = ln(I 1,θi / I2,θi )。According to the angles θ of each monochromator i and the corresponding absorption coefficient μ i the absorption coefficient of the sample 40 to be measured with respect to the angle θ of the monochromator i can be obtained (for example, it can be obtained by fitting with an existing fitting method (such as the least squares method)). According to the angles θ of each monochromator i and the corresponding I 1,θi the curve of the intensity of the X-rays measured by the first ionization chamber 20 with respect to the angle of the monochromator can be obtained.

[0055] The principle of the monochromator to monochromatize X-rays is Bragg diffraction. That is, after the X-rays irradiate on the monochromator crystal, Bragg diffraction will occur, and the diffracted X-rays are monochromatic light of a specific energy. There is a one-to-one correspondence between the energy of the monochromatic light and the incident angle of the X-rays on the monochromator crystal (i.e., the Bragg angle of the monochromator crystal), and the relationship between the two can be calculated by the following formula:

[0056] (1)

[0057] where θ is the Bragg angle of the monochromator crystal, h is Planck's constant, c is the speed of light, d is the interplanar spacing of the monochromator crystal. For example, for Si(111), d is 3.1356 Å, and E is the energy of the monochromatic light.

[0058] During the X-ray absorption spectrum experiment, the adjusted monochromator angle is not necessarily the Bragg angle of the monochromator crystal. For example, the monochromator angle may be the angle deviating from the oscillation center during the crystal oscillation process. Therefore, there is a fixed deviation between the monochromator angle and the Bragg angle of the monochromator crystal. If the monochromator angle is directly substituted into formula (1), the obtained energy is not the true energy of the monochromatic light. Energy calibration is to find the true energy of the monochromatic light corresponding to the monochromator angle, and then obtain the curve of the absorption coefficient of the sample 40 to be measured with respect to the energy of the monochromatic light (i.e., the X-ray absorption spectrum of the sample 40 to be measured).

[0059] S300: Determine the monochromator angle at the Glitch point of the monochromator crystal according to the curve of the intensity of the X-rays measured by the first ionization chamber 20 corresponding to the sample 40 to be measured with respect to the angle of the monochromator.

[0060] The monochromator will have a Glitch (fault) phenomenon at a specific angle, that is, when multiple crystal planes simultaneously satisfy the Bragg law, the X-ray intensity will drop sharply. Therefore, the curve of the intensity of the X-rays measured by the first ionization chamber 20 corresponding to the sample 40 to be measured with respect to the angle of the monochromator will have a sharp trough, that is, the trough is the Glitch point of the monochromator crystal, and the monochromator angle at the trough is the monochromator angle at the Glitch point of the monochromator crystal.

[0061] Since the Glitch point of the monochromator is an inherent physical property of the monochromator, the corresponding Bragg angle and energy will not change. Regardless of how much the monochromator angle deviates, the shape of the curve of the intensity of the X-rays measured by the first ionization chamber 20 with respect to the monochromator angle will not change, and the energy corresponding to each wave valley will not change either. Therefore, energy calibration can be performed based on the Glitch point of the monochromator. There may be multiple Glitch points of the monochromator. During energy calibration, any one Glitch point of the monochromator can be selected, and the monochromator angle at this Glitch point can be obtained.

[0062] S400: Determine the energy of the monochromatic light corresponding to the monochromator angle at the Glitch point of the monochromator crystal of the sample 40 to be measured based on the pre-acquired energy database of the Glitch point of the monochromator crystal.

[0063] The energy database of the Glitch point of the monochromator crystal refers to the correspondence between the Glitch point of the monochromator crystal and the energy of the monochromatic light, that is, it includes multiple Glitch points of the monochromator crystal and the energy of the monochromatic light corresponding to each Glitch point of the monochromator crystal. After obtaining the Glitch point of the monochromator crystal, the energy of the monochromatic light corresponding to this Glitch point of the monochromator crystal can be found in the energy database of the Glitch point of the monochromator crystal.

[0064] S500: Determine the Bragg angle at the Glitch point of the monochromator crystal based on the energy of the monochromatic light corresponding to the monochromator angle at the Glitch point of the monochromator crystal of the sample 40 to be measured and the Bragg formula.

[0065] Substituting the energy of the monochromatic light corresponding to the monochromator angle at the Glitch point of the monochromatic light crystal into formula (1), the Bragg angle at the Glitch point of the monochromator crystal can be obtained.

[0066] S600: Determine the mapping relationship between the monochromator angle and the Bragg angle of the sample 40 to be measured based on the monochromator angle and the Bragg angle at the Glitch point of the monochromator crystal as the first mapping relationship.

[0067] Step S600 specifically includes the following steps S610~S620:

[0068] S610: Obtain the difference between the Bragg angle and the monochromator angle at the Glitch point of the monochromator crystal as the first deviation; the first deviation is the deviation between the Bragg angle and the monochromator angle during this measurement process.

[0069] S620: Determine the Bragg angle corresponding to each monochromator angle of the sample 40 to be measured according to the first deviation.

[0070] Assume the first deviation is , the Bragg angle is , then the calculation formula is:

[0071] (2)

[0072] Thus, the first mapping relationship can be obtained.

[0073] S700: Based on the Bragg formula and the first mapping relationship, determine the correspondence between the monochromator angle and the energy of the monochromatic light of the sample 40 to be measured.

[0074] Through the first mapping relationship, the Bragg angle corresponding to each monochromator angle can be obtained, and then the energy of the corresponding monochromatic light can be calculated according to the Bragg angle. The specific calculation formula is as follows:

[0075] (3)

[0076] S800: Based on the correspondence between the monochromator angle and the energy of the monochromatic light of the sample 40 to be measured, convert the curve of the absorption coefficient of the sample 40 to be measured changing with the monochromator angle into the curve of the absorption coefficient of the sample 40 to be measured changing with the energy of the monochromatic light.

[0077] The specific conversion method is as follows:

[0078] Each absorption coefficient of the sample 40 to be measured corresponds to a monochromator angle, and this monochromator angle corresponds to an energy of a monochromatic light. Thus, the energy of the monochromatic light corresponding to each absorption coefficient can be obtained. By fitting the absorption coefficients and the corresponding energies of the monochromatic light, the curve of the absorption coefficient of the sample 40 to be measured changing with the energy of the monochromatic light can be obtained, that is, the X-ray absorption spectrum of the sample 40 to be measured.

[0079] In step S400, the energy database of the monochromator Glitch point can be obtained by pre-measurement. The measurement method is as follows:

[0080] Place the standard sample between the first ionization chamber 20 and the second ionization chamber 30, and conduct an X-ray absorption spectrum experiment on the standard sample to obtain the curve of the absorption coefficient of the standard sample changing with the monochromator angle and the curve of the intensity of the X-ray measured by the first ionization chamber 20 corresponding to the standard sample changing with the monochromator angle. The standard sample refers to a sample with significant near-edge characteristic peaks in the X-ray absorption spectrum. For example, the standard sample of zinc (Zn) element is zinc foil, which is a physical property and corresponds to a fixed energy value (for example, the energy of the K-edge white line peak of Zn is 9669 eV). Substitute it into the Bragg formula (1), and the characteristic peak Bragg angle of the monochromator crystal corresponding to the characteristic peak energy can be obtained , for a specific element, is a fixed value. For example, for Zn is 11.7986966°. In the curve of the absorption coefficient of the standard sample varying with the monochromator angle, the absorption coefficient of the standard sample corresponding to the characteristic peak energy is the peak of the curve. The monochromator angle corresponding to the peak of the curve of the absorption coefficient of the standard sample varying with the monochromator angle is the monochromator angle corresponding to the characteristic peak energy, which is denoted as , corresponding to . Thus, the difference between the two can be calculated as , which is used as the second deviation. This second deviation is the difference between the Bragg angle of the monochromator crystal and the monochromator angle of the standard sample. According to this second deviation, all other monochromator angles can be converted to the Bragg angles of the monochromator crystal (i.e., obtaining the Bragg angles of the monochromator crystal corresponding to the monochromator angles). The specific calculation formula is as follows:

[0081] (2)

[0082] where is the Bragg angle of the monochromator crystal corresponding to the monochromator angle . Then, substituting into formula (1), the energy E of the monochromatic light corresponding to the monochromator angle j can be obtained (i.e., obtaining the correspondence between the monochromator angle of the standard sample and the energy of the monochromatic light).

[0083] Then, the monochromator angles corresponding to the troughs of the curve of the X-ray intensity measured by the first ionization chamber 20 corresponding to the standard sample varying with the monochromator angle can be obtained, which are the monochromator angles at each monochromator Glitch point. According to the correspondence obtained above, the energies of the corresponding monochromatic lights can be obtained, that is, the energies of the monochromatic lights at each monochromator Glitch point, thereby forming an energy database of the monochromator Glitch points.

[0084] Next, the energy calibration of zinc oxide (ZnO) is performed using the energy calibration method of the embodiment of the present invention.

[0085] Before measuring the ZnO sample, an energy database of the monochromator crystal Glitch points can be obtained first. The specific method is as follows:

[0086] Perform an X-ray absorption spectrum experiment on the zinc foil to obtain the curve of the absorption coefficient of the zinc foil varying with the monochromator angle (as shown in Figure 3 ) and the curve of the X-ray measured by the first ionization chamber 20 corresponding to the zinc foil varying with the monochromator angle (as shown in Figure 4 ). Figure 3In the equation (1), the monochromator angle at the peak is -0.0374272°, and the energy of the corresponding monochromatic light is the characteristic peak energy of zinc, i.e., 9669 eV. Substituting the characteristic peak energy into formula (1), the corresponding characteristic peak Bragg angle is 11.7986966°, from which the second deviation is 11.8361238°. According to the second deviation, the remaining monochromator angles can be converted into Bragg angles, and then converted into the corresponding monochromatic light energy, thereby obtaining the X-ray absorption spectrum of zinc foil (such as Figure 5 At the same time, Figure 4 The intensity (I0) of the X-ray measured by the first ionization chamber 20 changes with the energy (E) of the monochromatic light (eg Figure 6 shown); Figure 6 There are multiple troughs in the image. For example, four points numbered 1, 2, 3 and 4 can be obtained as monochromator crystal Glitch points, and their corresponding energies can be obtained to form an energy database of monochromator crystal Glitch points, wherein the energy corresponding to the monochromator crystal Glitch point numbered 1 is 9981.74 eV, the energy corresponding to the monochromator crystal Glitch point numbered 2 is 9800.31 eV, the energy corresponding to the monochromator crystal Glitch point numbered 3 is 9772.23 eV, and the energy corresponding to the monochromator crystal Glitch point numbered 4 is 9708.23 eV.

[0087] After obtaining the energy database of the monochromator crystal glitch point, an X-ray absorption spectrum experiment can be performed on the ZnO sample to obtain the variation curve of the absorption coefficient of ZnO with the monochromator angle (such as Figure 7 As shown in FIG. 1 ) and the curve of the X-ray measured by the first ionization chamber 20 corresponding to ZnO as the monochromator angle changes (as shown in FIG. Figure 8 ). Figure 8 and Figure 4 It can be seen that the two have the same shape. Figure 8 There are also four Glitch points numbered 1 to 4. Choose any Glitch point, for example, Glitch point numbered 4. Figure 6 The energy corresponding to the Glitch point 4 is 9708.23 eV. According to formula (1), the Bragg angle corresponding to the energy can be obtained. Then, according to Figure 8 It can be seen that the monochromator angle at Glitch point 4 is 0.5931400°. The first deviation can be obtained based on the Bragg angle and the monochromator angle. Then, all other monochromator angles can be converted into Bragg angles based on the first deviation, and the Bragg angles can be converted into the energy of monochromatic light. Thus, the relationship curve between the absorption coefficient of ZnO and the energy of monochromatic light can be obtained (such as Figure 9 ), which is the X-ray absorption spectrum of ZnO.

[0088] The energy calibration method of the X-ray absorption spectrum according to the embodiment of the present invention realizes real-time energy calibration based on the Glitches phenomenon of the monochromator crystal, without adding additional equipment, can significantly reduce the experimental complexity and cost, and the calibration accuracy can reach ±0.1 eV, meeting the requirements of high-precision experiments.

[0089] The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Various changes can be made to the above embodiments of the present invention. That is, all simple, equivalent changes and modifications made according to the claims and the content of the specification of the present invention application fall within the scope of the claims of the present invention patent. Those not described in detail in the present invention are all conventional technical contents.

Claims

1. An energy calibration method for X-ray absorption spectroscopy, characterized in that, Including the following steps: S100: Provide an X-ray absorption spectrometer, including a monochromator, a first ionization chamber, and a second ionization chamber sequentially arranged along the X-ray transmission direction; S200: Place the sample to be measured between the first ionization chamber and the second ionization chamber, and perform an X-ray absorption spectroscopy experiment on the sample to be measured to obtain a curve of the absorption coefficient of the sample to be measured varying with the monochromator angle and a curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the sample to be measured varying with the monochromator angle; S300: Determine the monochromator angle at the Glitch point of the monochromator crystal according to the curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the sample to be measured varying with the monochromator angle; S400: Based on the pre-acquired energy database of the Glitch point of the monochromator crystal, determine the energy of the monochromatic light corresponding to the monochromator angle at the Glitch point of the monochromator crystal of the sample to be measured; S500: Based on the energy of the monochromatic light corresponding to the monochromator angle at the Glitch point of the monochromator crystal of the sample to be measured and Bragg's formula, determine the Bragg angle at the Glitch point of the monochromator; S600: Based on the monochromator angle and the Bragg angle at the Glitch point of the monochromator crystal, determine the mapping relationship between the monochromator angle and the Bragg angle of the sample to be measured as the first mapping relationship; S700: Based on Bragg's formula and the first mapping relationship, determine the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the sample to be measured; S800: Based on the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the sample to be measured, convert the curve of the absorption coefficient of the sample to be measured varying with the monochromator angle into a curve of the absorption coefficient of the sample to be measured varying with the energy of the monochromatic light.

2. The energy calibration method of the X-ray absorption spectrum according to claim 1, wherein Step S300 specifically includes: Obtain the trough in the curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the sample to be measured varying with the monochromator angle as the Glitch point of the monochromator crystal; Obtain the monochromator angle corresponding to the trough as the monochromator angle at the Glitch point of the monochromator crystal.

3. The energy calibration method of the X-ray absorption spectrum according to claim 1, wherein Step S600 specifically includes: Obtain the difference between the Bragg angle and the monochromator angle at the Glitch point of the monochromator crystal as the first deviation; Determine the Bragg angle corresponding to each monochromator angle of the sample to be measured according to the first deviation.

4. The energy calibration method of the X-ray absorption spectrum according to claim 1, wherein Step S800 specifically includes: According to the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the sample to be measured, obtain the energy of the monochromatic light corresponding to each monochromator angle in the curve of the absorption coefficient of the sample to be measured varying with the monochromator angle; Replace each monochromator angle with the energy of the monochromatic light corresponding to the monochromator angle to obtain the curve of the absorption coefficient of the sample to be measured varying with the energy of the monochromatic light.

5. The energy calibration method of the X-ray absorption spectrum according to claim 1, characterized in that The energy database of the Glitch point of the monochromator includes the Glitch point of the monochromator and the energy of the monochromatic light corresponding to the Glitch point of the monochromator.

6. The energy calibration method of the X-ray absorption spectrum according to claim 5, characterized in that, The energy database of the Glitch point of the monochromator is obtained by pre-measurement, and the measurement method includes: Place the standard sample between the first ionization chamber and the second ionization chamber, and conduct an X-ray absorption spectrum experiment on the standard sample to obtain the variation curve of the absorption coefficient of the standard sample with the monochromator angle and the variation curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the standard sample with the monochromator angle; wherein, the X-ray absorption spectrum of the standard sample has significant near-edge characteristic peaks, and the energy of the monochromatic light corresponding to the near-edge characteristic peaks is a fixed value; Based on the variation curve of the absorption coefficient of the standard sample with the monochromator angle and the energy of the monochromatic light corresponding to the near-edge characteristic peaks, determine the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the standard sample; Based on the variation curve of the intensity of the X-ray measured by the first ionization chamber corresponding to the standard sample with the monochromator angle, determine the Glitch point of the monochromator crystal and the monochromator angle at the Glitch point of the monochromator crystal; According to the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the standard sample, determine the energy of the monochromatic light at the Glitch point of the monochromator crystal.

7. The energy calibration method of the X-ray absorption spectrum according to claim 6, characterized in that, Based on the variation curve of the absorption coefficient of the standard sample with the monochromator angle and the energy of the monochromatic light corresponding to the near-edge characteristic peaks, determining the corresponding relationship between the monochromator angle and the energy of the monochromatic light of the standard sample specifically includes: Obtain the monochromator angle at the peak of the variation curve of the absorption coefficient of the standard sample with the monochromator angle as the monochromator angle of the near-edge characteristic peak; Based on the energy of the monochromatic light corresponding to the near-edge characteristic peak, determine the Bragg angle corresponding to the near-edge characteristic peak; Obtain the difference between the Bragg angle of the near-edge characteristic peak and the monochromator angle of the near-edge characteristic peak as the second deviation; Based on the second deviation, determine the Bragg angle corresponding to each monochromator angle of the standard sample; Based on the Bragg angle corresponding to each monochromator angle and the Bragg formula, determine the energy of the monochromatic light corresponding to the monochromator angle.

8. The energy calibration method of the X-ray absorption spectrum according to claim 1, characterized in that, The relationship between the Bragg angle and the energy of the monochromatic light is: , where θ is the Bragg angle of the monochromator crystal, h is Planck's constant, c is the speed of light, d is the crystal plane spacing of the monochromator crystal, and E is the energy of the monochromatic light.

Images