A quartz 128cm -1 Pressure Calibration Method for Raman Peak Shift

Abstract

This invention discloses a method based on quartz 128cm ‑1 A pressure calibration method for Raman peak displacement, comprising obtaining the temperature of the quartz wafer inside the sample chamber; if the temperature of the quartz wafer is room temperature, then applying a first pressure calibration function to the quartz wafer at a pressure of 128 cm⁻¹. ‑1 The pressure corresponding to the Raman peak displacement is used for calibration; if the temperature of the quartz wafer is higher than room temperature, the pressure of the quartz 128cm wafer is calibrated according to the second pressure calibration function. ‑1 The pressure corresponding to the Raman peak displacement is used for calibration. This invention, based on a pressure calibration function at different temperatures, can accurately obtain the pressure values ​​corresponding to different temperatures, resulting in more precise pressure calibration with smaller errors.

Description

Technical Field

[0001] This invention relates to the field of pressure calibration technology. More specifically, it relates to a method based on quartz 128cm... -1 Pressure calibration method for Raman peak displacement. Background Technology

[0002] Hydrothermal diamond-anvil cell (HDAC) is a crucial high-temperature and high-pressure experimental technique for studying hydrothermal system reactions, with wide applications in earth sciences. This technique uses two diamond anvils pressed together on a centrally perforated inert metal gasket (such as a rhenium plate) to form a sealed sample chamber. The chamber is heated by two resistance wire furnaces, achieving temperature and pressure conditions up to 950°C and 2.5 GPa. During the experiment, in-situ observation of the sample can be performed using optical observation and spectral analysis (such as laser Raman spectroscopy) to obtain real-time information about the sample's reaction under high temperature and pressure conditions. Accurate pressure calibration is crucial for interpreting experimental results in HDAC experiments, but limitations such as the small sample chamber volume make accurate pressure control difficult. Traditionally, for simple fluid systems (such as H₂O, H₂O-NaCl), the pressure corresponding to the experimental temperature can be estimated using known equations of state (EoS). However, real-world experimental systems are complex and diverse, and there are currently no readily available EoS equations for pressure calculation.

[0003] In recent years, pressure calibration methods using calibration minerals (such as quartz, anhydrite, and zircon) have been introduced in HDAC experimental pressure calibration. The characteristic Raman spectral peak positions of these calibration minerals are functions of temperature (T) and pressure (P). Quartz (SiO2) has a simple composition and is a commonly found mineral in the Earth's crust; adding quartz calibration minerals to the sample chamber will not interfere with the experimental reaction. Moreover, compared with other minerals, quartz Raman peak positions exhibit high sensitivity to pressure shifts; for example, Schmidt and Ziemann (2000) systematically measured the 464 cm⁻¹ of quartz under different temperature and pressure conditions. -1 Raman peak position, fitted to 464cm -1 A pressure calibration method based on the Raman peak position at 464 cm⁻¹ in quartz was established by investigating the functional relationship between peak position and temperature and pressure. This method is applicable to temperature and pressure conditions up to 560℃ and 2.1 GPa, with an error of ±50 MPa.

[0004] However, quartz 464cm -1 Raman peak positions often overlap with characteristic Raman peak positions of other silicate minerals, requiring peak fitting processing of the acquired spectra, which easily introduces errors. (128cm) -1The Raman peak position is also a characteristic Raman peak of quartz. This Raman peak position, at room temperature, exhibits high Raman peak intensity and a small full width at half maximum (FWHM), meeting the ideal conditions for establishing a Raman peak position pressure sensor. (Quartz 128cm) -1 The Raman peak position can also effectively avoid other silicate Raman peaks, making spectral fitting simpler and more accurate. However, because the interference filters of previous Raman equipment could not completely eliminate wavenumbers less than 150 cm⁻¹, -1 The plasma line caused the measurement of 128cm -1 The accuracy of Raman peak position displacement is relatively low. Summary of the Invention

[0005] This invention provides a quartz 128cm -1 A pressure calibration method for Raman peak displacement is proposed to address at least one of the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a quartz 128cm -1 A pressure calibration method for Raman peak displacement, the method includes

[0008] The temperature of the quartz wafer inside the sample chamber is obtained. If the temperature of the quartz wafer is room temperature, the quartz wafer is calibrated according to the first pressure calibration function at a depth of 128 cm. -1 The pressure corresponding to the Raman peak displacement is calibrated.

[0009] If the temperature of the quartz wafer is higher than room temperature, then the second pressure calibration function should be applied to the quartz 128cm. -1 The pressure corresponding to the Raman peak displacement is used for calibration.

[0010] Optionally, the first pressure calibration function is:

[0011] ΔV 128 (P1, 23℃) = -0.8363 × P1 2 +7.0812×P1-0.0455,

[0012] Where, ΔV 128 (P1, 23℃) represents the quartz Raman spectrum collected at room temperature (23℃) after fitting correction at a quartz 128cm⁻¹. -1 The relative displacement of the Raman peak position, P1 represents the hydrostatic pressure exerted on the quartz wafer in the sample chamber, and P1≤2100Mpa;

[0013] The second pressure calibration function is

[0014] ΔV 128=1.20176×10 -10 ×T 4 -1.64508×10 -7 ×T 3 +2.0665×10 -5 ×T 2 -0.02134×T

[0015] +0.00599×P² + 1.60394×10 -5 ×T×P2+0.48515,

[0016] Where T represents temperature, 23℃ <T≤700℃,ΔV 128 This indicates the quartz Raman spectrum collected at temperature T, after fitting correction, for a quartz 128cm⁻¹. -1 The relative displacement of the Raman peak position, P2 represents the pressure corresponding to temperature T, P2 < 1200 MPa.

[0017] Optionally, the calibration of quartz 128cm according to the first pressure calibration function... -1 Calibration of the pressure corresponding to the Raman peak displacement includes

[0018] The Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source were collected at room temperature, and mathematical fitting and correction were performed on the Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source.

[0019] The required samples, solutions, and quartz wafers were encapsulated in a hydrothermal diamond pressure chamber, and the Raman spectra of the encapsulated quartz and the Raman spectra of the mercury lamp light source were collected at room temperature.

[0020] Mathematical fitting and correction were performed on the Raman spectra of quartz before and after packaging at room temperature to obtain the Raman spectra of quartz at room temperature (128 cm⁻¹). -1 Relative displacement of Raman peaks;

[0021] The quartz 128cm at room temperature -1 Substituting the relative displacement of the Raman peak position into the first pressure calibration function, we obtain 128 cm for the quartz peak. -1 The pressure corresponding to the Raman peak displacement.

[0022] Optionally, the mathematical fitting and correction of the quartz Raman spectra before and after packaging at room temperature includes...

[0023] All obtained Raman spectra were mathematically fitted using baseline removal and peak position fitting methods.

[0024] Using the standard peak position of a mercury lamp light source as a reference, and based on the difference between the fitted Raman peak position of the mercury lamp light source before and after packaging and the standard peak position of the mercury lamp, the quartz 128 cm⁻¹ peak position in the same spectrum before and after packaging was analyzed. -1The spectrum of the band was corrected to obtain the quartz 128cm before and after packaging. -1 Raman peak position.

[0025] Optionally, the method further includes

[0026] Based on the quartz 128cm before correction and encapsulation -1 Raman peak position and calibrated encapsulated quartz 128cm -1 The difference in Raman peak positions was obtained from quartz at room temperature at 128 cm⁻¹. -1 Relative displacement of Raman peaks;

[0027] Based on the different types and densities of liquids loaded in the sample chamber, the corresponding quartz 128 cm⁻¹ at room temperature was obtained. -1 Relative displacement of Raman peaks.

[0028] Optionally, the calibration of quartz 128cm according to the second pressure calibration function... -1 Calibration of the pressure corresponding to the Raman peak displacement includes

[0029] The Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source were collected, and mathematical fitting and correction were performed on the Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source.

[0030] A certain amount of deionized water is sealed into the sample chamber, and the spacer between the two diamonds is trained to make the sample chamber reach an isochoric state.

[0031] The sample is sealed using a trained gasket, and the required sample, solution and quartz wafer are encapsulated in the hydrothermal diamond pressure chamber sample cavity.

[0032] Raman spectra of quartz under high-temperature conditions and Raman spectra from a mercury lamp source were collected. Mathematical fitting and correction were performed on the collected quartz Raman spectra at different temperatures to obtain the corresponding 128 cm⁻¹ quartz spectra at different temperatures. -1 Relative displacement of Raman peaks;

[0033] Quartz 128cm at different temperatures -1 By substituting the relative displacement of the Raman peak position into the second pressure calibration function, the 128 cm⁻¹ of quartz at different temperatures was obtained. -1 The pressure corresponding to the Raman peak displacement.

[0034] Optionally, the spacer between the two diamonds used for training to achieve an isochoric state in the sample cavity includes...

[0035] The hydrothermal diamond chamber is heated according to a preset first heating rate until the bubbles inside the chamber disappear. The temperature T at which the bubbles first disappear is recorded. h1 Continue heating until the temperature exceeds the preset target temperature;

[0036] The hydrothermal diamond pressing chamber was cooled down, and after bubbles reappeared inside, the chamber was heated again until the bubbles disappeared. The temperature T at which the bubbles disappeared for the second time was recorded. h2 , among which, T h2 <T h1 ;

[0037] The hydrothermal diamond chamber is repeatedly heated and cooled until the temperature difference between two consecutive disappearances of bubbles reaches a preset range, at which point the sample chamber reaches an isochoric state.

[0038] Optionally, if the temperature T during the experiment is when the bubbles disappear for the second time... h2 Greater than or equal to the temperature T at which the bubble first disappears h1 or T h1 -T h2 If the value is greater than the preset range, the data set is discarded and the experiment is repeated after resealing the sample and adding training pads.

[0039] Optionally, the mathematical fitting and correction of the acquired quartz Raman spectrum includes...

[0040] The temperature was increased according to a preset heating rate, and Raman spectra of quartz and mercury lamp light source were collected at different temperatures.

[0041] Mathematical fitting was performed on the collected quartz Raman spectra and the Raman spectra of the mercury lamp light source;

[0042] Using the standard peak position of a mercury lamp light source as a reference, and based on the difference between the Raman peak positions of mercury lamp light sources at different temperatures and the standard peak position of the mercury lamp after fitting, the results were analyzed for quartz 128 cm⁻¹ light sources at different temperatures. -1 The spectrum of the band was corrected to obtain the 128 cm⁻¹ quartz at different temperatures after correction. -1 Raman peak position of the band;

[0043] Based on the quartz 128cm before the correction and encapsulation -1 Raman peak positions and quartz 128 cm⁻¹ at different temperatures after correction -1 The difference in Raman peak positions was obtained from quartz 128 cm⁻¹ at different temperatures. -1 Relative displacement of Raman peaks.

[0044] Optionally, the method further includes temperature calibration of the hydrothermal diamond cavity thermocouple.

[0045] The temperature of the hydrothermal diamond pressure chamber thermocouple is calibrated based on the melting point of different crystals and the freezing point or triple point of the liquid system.

[0046] The beneficial effects of this invention are as follows:

[0047] This invention uses a training pad to achieve an isochoric state in the sample chamber of the hydrothermal diamond pressure chamber, reducing the error caused by deformation of the sample chamber during heating. Based on the first pressure calibration function and the second pressure calibration function, this invention can accurately obtain the pressure value at different temperatures, making the pressure calibration more precise and with smaller errors. Attached Figure Description

[0048] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0049] Figure 1(a) shows a schematic diagram of the structure of the hydrothermal diamond pressure chamber of the present invention;

[0050] Figure 1(b) shows a schematic diagram of the sealed sample chamber of the present invention;

[0051] Figure 2 This shows a 128cm quartz sample after fitting and correction according to the present invention. -1 A schematic diagram showing the relationship between the relative displacement of Raman peaks and temperature and pressure. Detailed Implementation

[0052] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further explains the invention. Similar components in the drawings are indicated by the same reference numerals. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0053] This invention provides a quartz 128cm -1 A pressure calibration method for Raman peak displacement is proposed, which offers higher accuracy, ease of operation, and applicability to a wider temperature and pressure range. Based on a quartz 128cm³ test chamber... -1 The current state of Raman spectroscopy research, based on quartz 128cm -1 The relationship between Raman peak displacement and temperature and pressure conditions is fitted to the pressure calibration equation, which improves the accuracy of pressure calibration technology in high temperature and high pressure experiments and expands the application field of pressure calibration technology.

[0054] Based on quartz 128cm -1 The pressure calibration method for Raman peak displacement includes

[0055] The temperature of the quartz wafer inside the sample chamber is obtained. If the temperature of the quartz wafer is room temperature, the quartz wafer is calibrated according to the first pressure calibration function at a depth of 128 cm. -1 The pressure corresponding to the Raman peak displacement is calibrated. In this invention, room temperature refers to 23°C.

[0056] If the temperature of the quartz wafer is higher than room temperature, then the second pressure calibration function should be applied to the quartz 128cm. -1 The pressure corresponding to the Raman peak displacement is used for calibration.

[0057] Wherein, the first pressure calibration function is

[0058] ΔV 128 (P1, 23℃) = -0.8363 × P1 2 +7.0812×P1-0.0455,

[0059] Where, ΔV 128 (P1, 23℃) represents the quartz Raman spectrum collected at room temperature (23℃) after fitting correction at a quartz 128cm⁻¹. -1 The relative displacement of the Raman peak position, P1 represents the hydrostatic pressure exerted on the quartz wafer in the sample chamber, and P1≤2100MPa;

[0060] The second pressure calibration function is:

[0061] ΔV 128 =1.20176×10 -10 ×T 4 -1.64508×10 -7 ×T 3 +2.0665×10 -5 ×T 2 -0.02134×T

[0062] +0.00599×P² + 1.60394×10 -5 ×T×P2+0.48515,

[0063] Where T represents temperature, 23℃ <T≤700℃,ΔV 128 This indicates the quartz Raman spectrum collected at temperature T, after fitting correction, for a quartz 128cm⁻¹. -1 The relative displacement of the Raman peak position, P2 represents the pressure corresponding to temperature T, P2 < 1200 MPa.

[0064] Based on the first pressure calibration function, quartz 128cm -1 Calibration of the pressure corresponding to the Raman peak displacement includes

[0065] The Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source were collected at room temperature, and mathematical fitting and correction were performed on the Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source.

[0066] The required samples, solutions, and quartz wafers were encapsulated in a hydrothermal diamond pressure chamber, and the Raman spectra of the encapsulated quartz and the Raman spectra of an external mercury lamp light source were collected at room temperature.

[0067] Mathematical fitting and correction were performed on the Raman spectra of quartz before and after packaging at room temperature to obtain the Raman spectra of quartz at room temperature (128 cm⁻¹). -1 Relative displacement of Raman peaks;

[0068] All obtained Raman spectra were mathematically fitted using baseline removal and peak position fitting methods.

[0069] Using the standard peak position of a mercury lamp light source as a reference, and based on the difference between the fitted Raman peak position of the mercury lamp light source before and after packaging and the standard peak position of the mercury lamp, the quartz 128 cm⁻¹ peak position in the same spectrum before and after packaging was analyzed. -1 The spectrum of the band was corrected to obtain the quartz 128cm before and after packaging. -1 Raman peak position.

[0070] Based on 128cm quartz crystal before encapsulation after calibration at room temperature -1 Raman peak position and calibrated encapsulated quartz 128cm -1 The difference in Raman peak positions was obtained from quartz at room temperature at 128 cm⁻¹. -1 Relative displacement of Raman peaks;

[0071] Quartz 128cm at room temperature -1 Substituting the relative displacement of the Raman peak position into the first pressure calibration function, we obtain the quartz peak position at room temperature at 128 cm⁻¹. -1 The pressure corresponding to the Raman peak displacement.

[0072] Based on the different types and densities of liquids loaded in the sample chamber, the corresponding quartz 128 cm⁻¹ at room temperature was obtained. -1 The relative displacement of the Raman peak position is used to obtain the corresponding pressure.

[0073] Based on the second pressure calibration function, quartz 128cm -1 Calibration of the pressure corresponding to the Raman peak displacement includes

[0074] The original Raman spectra of the quartz before packaging and the Raman spectra of the mercury lamp source were collected, and mathematical fitting and correction were performed on the original Raman spectra of the quartz before packaging and the Raman spectra of the mercury lamp source.

[0075] Using the standard peak position of a mercury lamp light source as a reference, and based on the difference between the fitted Raman peak position of the mercury lamp light source before packaging and the standard peak position of the mercury lamp, the quartz 128 cm⁻¹ peak position in the same spectrum before packaging was analyzed. -1 The spectrum of the band was corrected to obtain the corrected quartz 128cm before packaging. -1 Raman peak position;

[0076] A certain amount of deionized water is sealed into the sample chamber, and the spacer between the two diamonds is trained to make the sample chamber reach an isochoric state.

[0077] The sample is sealed using a trained gasket, and the required sample, solution and quartz wafer are encapsulated in the hydrothermal diamond pressure chamber sample cavity.

[0078] The hydrothermal diamond chamber is heated according to a preset first heating rate until the bubbles inside the chamber disappear. The temperature T at which the bubbles first disappear is recorded. h1 Continue heating until the temperature exceeds the preset target temperature;

[0079] The hydrothermal diamond pressing chamber was cooled down, and after bubbles reappeared inside, the chamber was heated again until the bubbles disappeared. The temperature T at which the bubbles disappeared for the second time was recorded. h2 , among which, T h2 <T h1 ;

[0080] Repeatedly heat up and cool down the hydrothermal diamond chamber until the temperature difference between two consecutive disappearances of bubbles reaches the preset range, that is, the sample chamber reaches the isovolumetric state.

[0081] If during the experiment, the temperature T when the bubbles disappear for the second time... h2 Greater than or equal to the temperature T at which the bubble first disappears h1 or T h1 -T h2 If the value is greater than the preset range, the data set is discarded and the experiment is repeated after resealing the sample and adding training pads.

[0082] Multiple sample data were acquired, and the temperature was increased according to the preset second heating rate. Based on experimental requirements, Raman spectra of quartz and mercury lamp light sources were collected at different temperatures. Mathematical fitting and correction were performed on the collected quartz Raman spectra at different temperatures to obtain the corresponding quartz 128cm⁻¹ spectra at different temperatures. -1 Relative displacement of Raman peaks;

[0083] Using the standard peak position of a mercury lamp light source as a reference, and based on the difference between the Raman peak positions of mercury lamp light sources at different temperatures after fitting and the standard peak position of the mercury lamp, the quartz 128 cm⁻¹ peak position in the same spectrum was analyzed. -1 The spectrum of the band was corrected to obtain the 128 cm⁻¹ quartz at different temperatures after correction. -1 Corrected peak position of the band;

[0084] 128cm quartz crystal before packaging after calibration -1 Raman peak position and quartz 128 cm⁻¹ at different temperatures after correction -1 The difference in Raman peak positions was obtained from quartz 128 cm⁻¹ at different temperatures. -1 Relative displacement of Raman peaks.

[0085] The temperature of the quartz wafer and the corresponding quartz 128cm at that temperature. -1 Substituting the relative displacement of the Raman peak position into the second pressure calibration function allows us to calculate the quartz 128cm at that temperature. -1 The pressure corresponding to the Raman peak displacement.

[0086] The method also includes calibrating the temperature of the hydrothermal diamond pressure-cavity thermocouple.

[0087] The hydrothermal diamond cavity thermocouple measures the temperature of the sample cavity via a thermocouple. The temperature of the thermocouple in the hydrothermal diamond cavity is calibrated based on the melting point of different crystals and the freezing point or triple point of the liquid system to improve the accuracy of temperature measurement. Specifically, the temperature of the thermocouple in the hydrothermal diamond cavity can be calibrated using the freezing point of pure water (0℃), the triple point of NaCl-H2O system (-21.2℃), the melting point of NaCl (800.8℃), and NaNO3 (306.8℃).

[0088] The method also includes

[0089] The Raman spectrometer was calibrated using a neon lamp before collecting spectra.

[0090] In one specific embodiment, based on quartz 128cm -1 The pressure calibration method for Raman peak displacement includes

[0091] Measure the temperature of the quartz wafer inside the current sample chamber. If the temperature of the quartz wafer is room temperature, then apply the first pressure calibration function to the quartz wafer at 128 cm⁻¹. -1 The pressure corresponding to the Raman peak displacement is calibrated; in this embodiment, the room temperature is 23°C; if the temperature of the quartz wafer is greater than 23°C, the pressure of the quartz 128cm wafer is calibrated using the second pressure calibration function. -1 The pressure corresponding to the Raman peak displacement is used for calibration.

[0092] The first pressure calibration function is:

[0093] ΔV 128 (P1, 23℃) = -0.8363 × P1 2 +7.0812×P1-0.0455, (R1) 2 =0.9991)

[0094] Where, ΔV 128 (P1, 23℃) represents the quartz Raman spectrum collected at room temperature (23℃) after fitting correction at a quartz 128cm⁻¹. -1 The relative displacement of the Raman peak position, P1 represents the hydrostatic pressure exerted on the quartz wafer inside the sample chamber, and R1 2 This represents the standard error. This function is applicable under the conditions of 23℃ and P1≤2100MPa.

[0095] The second pressure calibration function is:

[0096] ΔV 128 =1.20176×10 -10 ×T4 -1.64508×10 -7 ×T 3 +2.0665×10 -5 ×T 2 -0.02134×T+0.005

[0097] 99×P² + 1.60394×10 -5 ×T×P2+0.48515,(R2 2 =0.9986)

[0098] Where T represents temperature, 23℃ <T≤700℃,ΔV 128 This indicates the quartz Raman spectrum collected at temperature T, after fitting correction, for a quartz 128cm⁻¹. -1 The relative displacement of the Raman peaks, P2 represents the pressure corresponding to temperature T, P2 < 1200 MPa, R2 2 Indicates the standard error.

[0099] Let the first pressure calibration equation at room temperature be:

[0100] ΔV 128 (P1, 23℃) = a1 × P1 2 +a2×P1+a3,

[0101] Where a1, a2, and a3 are the polynomial coefficients;

[0102] Let the second pressure calibration equation be:

[0103] ΔV 128 =c1×T 4 +c2×T 3 +c3×T 2 +c4×T+c5×P2+c6×T×P2+c7,

[0104] Where c1, c2, c3, c4, c5, c6 and c7 are the polynomial coefficients.

[0105] like Figure 2 The image shown is of quartz 128cm. -1 The relationship between the relative displacement of Raman peak positions and temperature and pressure. In the example, this was obtained through multiple experiments. Figure 2 The experimental sample data were used to fit the first pressure calibration function and the second pressure calibration function into the first pressure calibration equation and the second pressure calibration equation, respectively.

[0106] Table 1 shows the values ​​of the coefficients in the first pressure calibration equation.

[0107] <![CDATA[a1]]> <![CDATA[a2]]> <![CDATA[a3]]> -0.8363 7.0812 -0.0455

[0108] The first pressure calibration function is: ΔV 128 (P1, 23℃) = -0.8363 × P1 2 +7.0812×P1-0.0455.

[0109] Table 2 shows the values ​​of the coefficients in the second pressure calibration equation.

[0110] <![CDATA[c1]]> <![CDATA[c2]]> <![CDATA[c3]]> <![CDATA[c4]]> <![CDATA[c5]]> <![CDATA[c6]]> <![CDATA[c7]]> <![CDATA[1.20176×10 -10 ]]> <![CDATA[-1.64508×10 -7 ]]> <![CDATA[2.0665×10 -5 ]]> -0.02134 0.00599 <![CDATA[1.60394×10 -5 ]]> 0.48515

[0111] The second pressure calibration function is:

[0112] ΔV 128 =1.20176×10 -10 ×T 4 -1.64508×10 -7 ×T 3 +2.0665×10 -5 ×T 2 -0.02134×T

[0113] +0.00599×P² + 1.60394×10 -5 ×T×P2+0.48515.

[0114] Specifically, Figure 1(a) is a schematic diagram of the hydrothermal diamond pressure chamber of the present invention. The preparation work required before measuring the temperature of the quartz wafer is to clean the polishing pad and clean the diamond anvil. In this embodiment, the pad is a rhenium sheet with a diameter of 0.5 mm and a thickness of 0.25 mm, and the anvil surface diameter of the diamond anvil is 1 mm.

[0115] The equipment used in this embodiment includes an HDAC-VT type hydrothermal diamond pressure chamber, a PES1300 temperature controller, a HORIBA LabRAM HR Evolution high-resolution microconfocal laser Raman spectrometer, and an ultra-long focal length objective.

[0116] The temperature measurement of the hydrothermal diamond cavity thermocouple was calibrated at both high and low temperatures. The melting point of NaCl was selected for calibrating the temperature of the HDAC-VT type hydrothermal diamond cavity thermocouple. A moderately sized and relatively intact NaCl crystal was placed in the sample cavity, and the upper and lower diamond anvils were gently closed, ensuring no indentation between the anvil face and the rhenium plate, thus maintaining the pressure inside the sample cavity at standard atmospheric pressure. The HDAC-VT type hydrothermal diamond cavity was placed on the stage, and the sample cavity was heated using a PES1300 temperature controller. The melting point of NaCl is 800.8℃. The temperature was increased at a rate of 30℃ / min initially, then at 5℃ / min at 750℃, and finally at 1℃ / min at 790℃. The melting temperature of the crystal was observed when the temperature approached the melting point of the NaCl crystal. In this embodiment, the sample cavity refers to the cavity formed by the two diamond and rhenium plate holes in the upper and lower cavity of the hydrothermal diamond cavity.

[0117] It should be noted that the experimental procedure for calibration using the melting point of NaNO3 crystal is basically the same as the above experiment. The only difference is that the crystal in the sample chamber is replaced with NaNO3 crystal, and the heating rate is adjusted in different temperature ranges. The closer to the melting point of NaNO3 crystal, the slower the heating rate should be, so as to accurately calibrate the measurement temperature of the HDAC-VT type hydrothermal diamond pressure chamber thermocouple.

[0118] At low temperatures, the measured temperature of the HDAC-VT type hydrothermal diamond anvil cell was corrected based on the freezing point of the pure water system (0℃) and the triple point of NaCl in the NaCl-H2O system (-21.2℃). The difference between this hydrothermal diamond anvil cell and the one used on the heating platform is that the protective ring used in the low-temperature hydrothermal diamond anvil cell is wrapped with insulating paper, and a square hole is left in the middle of the ring to facilitate the displacement of the ceramic tube through the sleeve during the experiment. The specific procedure is as follows: after cleaning and polishing the rhenium plate and the anvil surface of the diamond anvil, an appropriate amount of deionized water is sealed in the sample cavity, and the pressure screw of the hydrothermal diamond anvil cell is loosened appropriately to ensure that the volume of the air bubbles in the sample cavity is suitable. The thermocouple of the HDAC-VT type hydrothermal diamond anvil cell is placed on the cooling platform, which mainly includes a computer, microscope, Omega TC-08 temperature measurement module, precision manual platform, and liquid nitrogen freezing device. The liquid nitrogen freezing apparatus needs to be connected sequentially to a high-purity nitrogen cylinder, a gas flow controller, a metering device, and a liquid nitrogen tank. The tail gas outlet of the liquid nitrogen tank uses an antifreeze container and a ceramic tube. Before the low-temperature calibration experiment, the hydrothermal diamond chamber needs to be placed under a microscope. Connect the K-type thermocouple used in the HDAC-VT type hydrothermal diamond chamber to the Omega TC-08 temperature measurement module. Adjust the precision manual platform so that the ceramic tube passes through the collar and is aligned with the sample chamber of the hydrothermal diamond chamber, with the ceramic tube approximately parallel to the microscope substrate. Before the experiment, first turn on the gas flow meter to introduce nitrogen gas to purge the air from the freezing apparatus before pouring in liquid nitrogen to prevent the air in the tube from freezing instantly and blocking the gas tube. During the experiment, first increase the gas flow rate by adjusting the gas flow meter, then adjust the precision manual platform to bring the ceramic tube opening close to the sample chamber. The temperature inside the sample chamber rapidly decreases to a supercooled state. Adjust the precision manual platform again to ensure that the measurement temperatures of the two K-type thermocouples are consistent, i.e., the temperature difference between the two K-type thermocouples does not exceed 0.5℃. When the temperature drops to -90℃, reduce the gas flow rate to allow the temperature to rise again. Simultaneously, adjust the precision manual platform to ensure the temperature measurements of the two K-type thermocouples remain consistent. When the temperature rises to approximately -20℃, adjust the precision manual platform to gradually move the ceramic tube away from the sample chamber. This experimental method can maintain a temperature change rate of no more than 1℃ / min. When the temperature approaches the observation point of -1℃, maintain this temperature for a period of time, then continue to slowly increase the temperature, recording the melting temperature of the last ice crystal in the sample chamber.

[0119] It is important to note that during the experiment, the ceramic tube opening should not be positioned directly above the thermocouple inside the hydrothermal diamond pressure chamber, and the airflow should not be too strong when approaching the observation point temperature; otherwise, the experimental temperature measurement will be inaccurate. In this embodiment, the freezing point of deionized water was found to be 0.1℃. The basic experimental steps for NaCl solution triple point calibration and freezing point calibration are the same as above, except that the deionized water in the sample chamber is replaced with a NaCl solution of a certain salinity. This embodiment uses a laboratory-prepared 20wt.% NaCl solution. The experimental procedure can be referred to the above freezing point calibration experimental procedure. When the previously frozen dark field of view suddenly becomes bright, this is the triple point of the NaCl solution. Record the above measured temperature; the difference between the measured temperature and the theoretical temperature should be less than 0.5℃.

[0120] After temperature calibration of the HDAC-VT type hydrothermal diamond chamber, quartz wafers are prepared. In this embodiment, the quartz sample used comes from the Sichuan Methylka 308 pegmatite vein, and the quartz is colorless and transparent. First, thin slices are ground and polished on both sides to a thickness of 100μm. Then, under a binocular microscope, quartz wafers of appropriate size are cut to meet the sample loading requirements of the hydrothermal diamond chamber.

[0121] Clean the sample chamber by placing the rhenium sheet into an ultrasonic cleaner; wipe the surfaces of the two diamond anvils in the hydrothermal diamond indenter with alcohol to ensure they are clean and dust-free.

[0122] Before acquiring the spectrum, the laser Raman spectrometer was calibrated using a neon lamp. In this embodiment, a Horiba LabRAM HR Evolution laser Raman spectrometer was used to acquire the quartz Raman spectrum. It was equipped with an OLYMPUS SLWD 20× objective lens (numerical aperture 0.25, working distance 25 mm), a 532.404 nm (Nd:YAG) laser, an 1800 gr / mm grating, and an objective lens exit laser energy of 40 mW, achieving a spectral resolution of 0.2 cm⁻¹. -1 .

[0123] An external mercury lamp was used during the experimental data collection process. The standard peak position of the mercury lamp was used as a reference for later correction of the position of the quartz Raman peak, thereby obtaining the quartz 128cm peak. -1 Relative displacement of Raman peaks.

[0124] The rhenium sheet between the two diamonds is trained to achieve an isochoric state in the sample cavity;

[0125] The prepared quartz wafer and deionized water are sealed in the sample chamber of the hydrothermal diamond pressure chamber. The pressure screw of the hydrothermal diamond pressure chamber is adjusted to make a certain volume of air bubbles appear in the sample chamber, as shown in Figure 1(b). The sealed sample chamber contains deionized water, quartz wafer and air bubbles.

[0126] Rhenium sheets that have not undergone high-temperature training are prone to deformation during experiments, leading to sample cavity shrinkage. Therefore, the sealed sample cavity must be repeatedly heated to achieve an isovolumetric state. The specific procedure is as follows: Place the hydrothermal diamond chamber on a heating platform. Initially, heat at a rapid rate when the temperature is low, then slow down the heating as it approaches the bubble disappearance temperature. Record the temperature T at which the bubbles first disappear within the sample cavity. h1 (i.e., the gas-liquid homogenization temperature), and then continue to heat up until it reaches 20°C above the preset target temperature, and hold the temperature for 20 minutes to observe whether the rhenium sheet deforms. In this embodiment, the preset target temperature is 800°C. No deformation of the rhenium sheet was observed. Then, cooling began until bubbles reappeared in the sample chamber, and then the temperature was raised again. The temperature at which the bubbles disappeared for the second time in the sample chamber, T, was measured and recorded. h2 The temperature at which the bubbles disappear for the second time is T. h2 <Temperature T of the first bubble disappearance> h1 Conversely, if the air quality is good, it indicates a leak in the sample chamber. In this case, the screws need to be tightened or the sample reloaded. Cycle heating and cooling repeatedly until the temperature difference between two consecutive instances of bubble disappearance is less than 1°C. At this point, the rhenium plate is considered to have completed training, and the sample chamber has reached an isochoric state.

[0127] Specifically, in this embodiment, the maximum target temperature is set to 800℃. During the training of the rhenium sheet, a preset first heating rate is used for stepwise heating. The preset first heating rate can be: first, heating at 30℃ / min to 500℃, then at 20℃ / min to 600℃, and then at 10℃ / min to 700℃. During this heating process, just before the bubbles disappear, the heating rate is changed to 1℃ / min. When the bubbles disappear, the temperature T of the first bubble disappearance is recorded. h1 Then, the temperature was increased at the set rate. When the temperature reached the target temperature of 800℃, it was increased to 20℃ above the target temperature and held at that temperature for 20 minutes. Then, the temperature was lowered. When bubbles reappeared in the sample chamber, the temperature was increased again at a rate of 1℃ / min until the bubbles disappeared for the second time. The temperature T at this point was recorded. h2 , among which, T h2 <T h1 Continue the above heating and cooling cycle until the temperature difference between two consecutive bubble disappearances is less than 1℃. If, during the experiment, the temperature T during the second bubble disappearance... h2 Greater than or equal to the temperature T at which the bubble first disappears h1 or T h1 -T h2 If the value is greater than or equal to 1℃, the data set is discarded, and the experiment is repeated after resealing the sample and applying the training pad. In this embodiment, the preset range for the temperature difference between two consecutive instances of bubble disappearance is 1℃.

[0128] Raman spectra of quartz before packaging and Raman spectra of mercury lamp light source were collected at room temperature;

[0129] The sample was sealed using a trained gasket. The required sample, solution, and quartz crystal were encapsulated together in the hydrothermal diamond pressure chamber sample cavity. The Raman spectra of the encapsulated quartz and the Raman spectra of the mercury lamp light source were collected at room temperature.

[0130] The temperature of the quartz wafer inside the sample chamber was measured. When the temperature was 23°C, the first pressure calibration function was applied to the 128cm quartz wafer. -1 The pressure corresponding to the Raman peak displacement is calibrated.

[0131] Mathematical fitting and correction were performed on the Raman spectra of quartz before and after encapsulation at room temperature to obtain the quartz 128cm... -1 Relative displacement of Raman peaks;

[0132] Quartz 128cm -1 Substituting the relative displacement of the Raman peak position into the first pressure calibration function, we obtain 128 cm⁻¹ for quartz. -1 The pressure corresponding to the Raman peak displacement.

[0133] The first pressure calibration function is:

[0134] ΔV 128 (P1, 23℃)(cm) -1 )=-0.8363×P1 2 +7.0812×P1-0.0455,

[0135] The first pressure calibration function is applicable under the conditions of ambient temperature (23℃) and P1 ≤ 2100MPa. Wherein, ΔV 128 (P1, 23℃) is the quartz Raman spectrum collected under high pressure and ambient temperature conditions, corrected by fitting. (128 cm⁻¹) -1 The relative displacement of the Raman peak position, P1 is the hydrostatic pressure exerted on the quartz crystal in the sample chamber (i.e. the pressure exerted on the quartz crystal by the fluid in the sealed sample chamber).

[0136] If the measured temperature of the quartz wafer exceeds 23°C, then the second pressure calibration function is used to calibrate the 128cm quartz wafer. -1 The pressure corresponding to the Raman peak displacement is used for calibration.

[0137] Multiple sample data were acquired, including Raman spectra of quartz and mercury lamp light sources at different temperatures. The acquired quartz Raman spectra were then fitted and corrected based on the Raman spectra of the mercury lamp light sources at different temperatures to obtain the corresponding quartz 128 cm⁻¹ spectra at different temperatures. -1 Relative displacement of Raman peaks.

[0138] In this embodiment, the quartz Raman spectrum was acquired using a Horiba LabRAM HR Evolution laser Raman spectrometer, equipped with an OLYMPUS SLWD 20× objective lens (numerical aperture of 0.25, working distance of 25 mm), a 532.404 nm (Nd:YAG) laser, an 1800 gr / mm grating, and an objective lens exit laser energy of 40 mW, achieving a spectral resolution of 0.2 cm⁻¹. -1 .

[0139] Before acquiring quartz Raman spectra, the Raman spectrometer was calibrated using a neon lamp. An external mercury lamp was used during the acquisition process, with its standard peak position serving as a reference for later correction of the quartz Raman peak positions.

[0140] Before sealing the sample chamber, Raman spectra of quartz and Raman spectra from an external mercury lamp source were acquired. Then, a certain amount of deionized water was placed inside the sample chamber to train it to an isochoric state. The required sample, solution, and quartz wafer were then sealed together within the hydrothermal diamond pressure chamber. Heating was then initiated, with a set of Raman spectra of quartz and mercury lamp source acquired every 50°C after reaching 100°C. Each time the temperature was raised to the acquisition temperature, it was held at that temperature for 3 minutes before acquiring the Raman spectra of quartz and the external mercury lamp source again. In this embodiment, heating was performed according to a preset second heating rate, which could be: 20°C / min for the temperature range from room temperature to 300°C; 10°C / min for the temperature range of 300–500°C; and 5°C / min for temperatures above 500°C.

[0141] This embodiment uses different heating rates to collect Raman spectra of quartz and mercury lamp light sources, which improves the accuracy of the collected Raman spectra.

[0142] Raman spectra were acquired using a single-window mode at a resolution of 320 cm⁻¹. -1 Centered on the wavenumber, the obtained Raman spectrum ranges from 77 to 593 cm⁻¹. -1 Three spectra were repeatedly acquired at each temperature point where Raman spectra were acquired, using an integration time of 10 seconds per acquisition and a cycle of 3 times. During the experiment, the uniform temperature at which the bubbles disappeared during two adjacent heating processes was recorded simultaneously. If the uniform temperature difference between two adjacent bubble disappearances was less than 1℃, it was determined that the sample cavity was of equal volume and without leakage, and the test results of that set were valid and usable; otherwise, the data of that set were discarded.

[0143] The experimentally obtained quartz Raman spectral data were fitted using PeakFit v4.12 software. To reduce the error caused by baseline operations, a method of simultaneously performing baseline removal (linear) and peak position fitting operations was adopted. Different mathematical equations were used for fitting different peak positions. For quartz 128 cm⁻¹ peaks...-1 The band Raman spectrum is fitted using the Gauss-Lorentz Amp equation, and the Raman spectrum generated by the mercury lamp source is fitted using the Beta Amp equation. Taking the standard peak position of the mercury lamp source as a reference, according to the difference between the Raman peak position of the mercury lamp source before encapsulation and the standard peak position of the mercury lamp, the quartz Raman spectrum before encapsulation is corrected to obtain the corrected quartz 128 cm -1 Raman peak position before encapsulation; according to the difference between the Raman peak position of the mercury lamp source at different temperatures after fitting and the standard peak position of the mercury lamp, the spectrum of the quartz 128 cm -1 band is corrected to obtain the corrected quartz 128 cm -1 Raman peak position at different temperatures;

[0144] By the difference between the corrected quartz 128 cm -1 Raman peak position before encapsulation and the corrected quartz 128 cm -1 Raman peak position at different temperatures, the relative displacement of the quartz 128 cm -1 Raman peak position at different temperatures is obtained;

[0145] The temperature and the relative displacement of the quartz 128 cm -1 Raman peak position corresponding to the temperature are substituted into the second pressure calibration function to obtain the pressure corresponding to the displacement of the quartz 128 cm -1 Raman peak position.

[0146] The second pressure calibration function is:

[0147] ΔV 128 = 1.20176×10 -10 ×T 4 - 1.64508×10 -7 ×T 3 + 2.0665×10 -5 ×T 2 - 0.02134×T

[0148] + 0.00599×P2 + 1.60394×10 -5 ×T×P2 + 0.48515,

[0149] The applicable temperature and pressure range of this second pressure calibration function is 23°C < T ≤ 700°C, P2 < 1200 MPa. Where, T is the temperature during Raman spectrum acquisition; ΔV 128 is the relative displacement of the corrected quartz 128 cm -1 Raman peak position of the quartz Raman spectrum collected at temperature T; P2 is the pressure corresponding to temperature T.

[0150] This invention achieves an isochoric state in the sample chamber of the hydrothermal diamond pressing chamber by training the rhenium sheet to do so, thus greatly reducing the size of the quartz 128cm³ sample. -1 The invention addresses the error in pressure calibration of Raman peak displacement; it improves the accuracy of spectral acquisition by setting different heating rates in different temperature ranges, and better protects the hydrothermal diamond pressure chamber; based on the first and second pressure calibration functions, the invention can accurately obtain pressure values ​​at different temperatures, resulting in more precise pressure calibration with smaller errors; the invention can also be applied to pressure calibration in fluid isochoric simulation experiments, estimation of diagenetic pressure in high-pressure metamorphic rocks containing quartz inclusions, and PT trajectory inversion of metamorphic processes.

[0151] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0152] It should also be noted that in the description of this invention, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0153] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method based on quartz 128 cm -1 The pressure calibration method for Raman peak displacement is characterized by, The method includes The temperature of the quartz wafer inside the sample chamber is obtained. If the temperature of the quartz wafer is at room temperature, the required sample, solution, and quartz wafer are encapsulated in the hydrothermal diamond pressure chamber sample chamber. The quartz wafer is then calibrated according to the first pressure calibration function at a pressure of 128 cm⁻¹. -1 The pressure corresponding to the Raman peak displacement is calibrated. The first pressure calibration function is ∆ V 128 ( P 1, 23℃)=-0.8363× P 1 2 +7.0812× P 1-0.0455， Where, ∆ V 128 ( P 1, 23℃) represents the quartz Raman spectrum collected at room temperature (23℃) and corrected for fitting, obtained from a quartz 128cm⁻¹ specimen. -1 Relative displacement of Raman peaks P 1 represents the hydrostatic pressure exerted on the quartz wafer within the sample chamber, and P 1 ≤ 2100 MPa; If the temperature of the quartz wafer is higher than room temperature, then the second pressure calibration function is applied to the quartz 128 cm⁻¹. -1 The pressure corresponding to the Raman peak displacement is calibrated. The second pressure calibration function is ∆ V 128 =1.20176×10 -10 × T 4 –1.64508×10 -7 × T 3 +2.0665×10 -5 × T 2 -0.02134× T +0.00599× P 2+1.60394×10 -5 × T × P 2+0.48515， in, T Indicates temperature, 23 ℃ < T ≤ 700 ℃, ∆ V 128 express T Quartz Raman spectra collected at the temperature and fitted and corrected for quartz 128 cm⁻¹ -1 Relative displacement of Raman peaks P 2 indicates T Temperature corresponding to pressure P 2 < 1200 MPa.

2. The pressure calibration method according to claim 1, characterized in that, The quartz 128 cm based on the first pressure calibration function -1 Calibration of the pressure corresponding to the Raman peak displacement includes The Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source were collected at room temperature, and mathematical fitting and correction were performed on the Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source. Raman spectra of a quartz wafer packaged at room temperature and an external mercury lamp light source were collected. Mathematical fitting and correction were performed on the Raman spectra of quartz before and after packaging at room temperature to obtain the Raman spectra of quartz at room temperature (128 cm⁻¹). -1 Relative displacement of Raman peaks; The quartz at room temperature 128 cm -1 Substituting the relative displacement of the Raman peak position into the first pressure calibration function, we obtain 128 cm for quartz. -1 The pressure corresponding to the Raman peak displacement.

3. The pressure calibration method according to claim 2, characterized in that, The mathematical fitting and correction of the quartz Raman spectra before and after packaging at room temperature includes... All obtained Raman spectra were mathematically fitted using baseline removal and peak position fitting methods. Using the standard peak position of a mercury lamp light source as a reference, and based on the difference between the fitted Raman peak position of the mercury lamp light source before and after packaging and the standard peak position of the mercury lamp, the quartz 128 cm⁻¹ peak position in the same spectrum before and after packaging was analyzed. -1 The spectrum of the band was corrected to obtain the quartz 128 cm⁻¹ before and after packaging. -1 Raman peak position.

4. The pressure calibration method according to claim 3, characterized in that, The method also includes Based on the quartz 128 cm before correction and encapsulation -1 Raman peak position and calibrated encapsulated quartz 128 cm -1 The difference in Raman peak positions was obtained from quartz at room temperature at 128 cm⁻¹. -1 Relative displacement of Raman peaks; Based on the different types and densities of liquids loaded in the sample chamber, the corresponding quartz 128 cm⁻¹ at room temperature was obtained. -1 Relative displacement of Raman peaks.

5. The pressure calibration method according to claim 1, characterized in that, The quartz 128 cm based on the second pressure calibration function -1 Calibration of the pressure corresponding to the Raman peak displacement includes The Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source were collected, and mathematical fitting and correction were performed on the Raman spectra of quartz before packaging and the Raman spectra of mercury lamp light source. A certain amount of deionized water is sealed into the sample chamber, and the spacer between the two diamonds is trained to make the sample chamber reach an isochoric state. The sample is sealed using a trained gasket, and the required sample, solution and quartz wafer are encapsulated in the hydrothermal diamond pressure chamber sample cavity. Raman spectra of quartz under high-temperature conditions and Raman spectra from an external mercury lamp were collected. Mathematical fitting and correction were performed on the collected quartz Raman spectra at different temperatures to obtain the corresponding quartz 128 cm⁻¹ spectra at different temperatures. -1 Relative displacement of Raman peaks; Quartz 128 cm at different temperatures -1 By substituting the relative displacement of the Raman peak position into the second pressure calibration function, the 128 cm⁻¹ of quartz at different temperatures was obtained. -1 The pressure corresponding to the Raman peak displacement.

6. The pressure calibration method according to claim 5, characterized in that, The spacer between the two diamonds used in the training process aims to achieve an isovolumetric state in the sample cavity. The hydrothermal diamond chamber is heated according to a preset first heating rate until the air bubbles inside the chamber disappear, and the temperature at which the air bubbles first disappear is recorded. T h1 Continue heating until the temperature exceeds the preset target temperature; The hydrothermal diamond pressing chamber was cooled down, and after bubbles reappeared inside, the chamber was heated again until the bubbles disappeared. The temperature at which the bubbles disappeared for the second time was recorded. T h2 ,in, T h2 < T h1 ; The hydrothermal diamond chamber is repeatedly heated and cooled until the temperature difference between two consecutive disappearances of bubbles reaches a preset range, at which point the sample chamber reaches an isochoric state.

7. The pressure calibration method according to claim 6, characterized in that, If the temperature at which the bubbles disappear for the second time during the experiment... T h2 Greater than or equal to the temperature at which the bubble first disappears T h1 or T h1 - T h2 If the value is greater than the preset range, discard the data set, reseal the sample and re-install the training pad, and then conduct the experiment again.

8. The pressure calibration method according to claim 5, characterized in that, The mathematical fitting and correction of the acquired quartz Raman spectra includes... The temperature was increased according to the preset heating rate, and the Raman spectra of quartz and mercury lamp light source were collected at different temperatures. Mathematical fitting was performed on the collected quartz Raman spectra and the Raman spectra of the mercury lamp light source; Using the standard peak position of a mercury lamp light source as a reference, and based on the difference between the Raman peak positions of mercury lamp light sources at different temperatures and the standard peak position of the mercury lamp after fitting, the results were analyzed for quartz 128 cm⁻¹ light at different temperatures. -1 The spectrum of the band was corrected to obtain the 128 cm⁻¹ quartz at different temperatures after correction. -1 Raman peak position; Based on the quartz 128 cm before the correction and encapsulation -1 Raman peak position and quartz 128 cm⁻¹ at different temperatures after correction -1 The difference in Raman peak positions was obtained from quartz at different temperatures at 128 cm⁻¹. -1 Relative displacement of Raman peaks.

9. The pressure calibration method according to claim 5, characterized in that, The method also includes temperature calibration of the hydrothermal diamond pressure-cavity thermocouple. The temperature of the hydrothermal diamond pressure chamber thermocouple is calibrated based on the melting point of different crystals and the freezing point or triple point of the liquid system.

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