Method for measuring temperature gradient between optical pressure standard fp resonator and temperature controlled copper cavity

Abstract

The application provides a method for measuring a temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity. The method comprises: determining sample data; fitting the sample data to obtain a first frequency change coefficient of a frequency change amount of a measurement cavity with respect to temperature change and a second frequency change coefficient of a frequency change amount of a reference cavity with respect to temperature change; determining a plurality of first thermal expansion coefficients of the measurement cavity and a plurality of second thermal expansion coefficients of the reference cavity; determining a plurality of first temperature-induced frequency change rates of the measurement cavity and a plurality of second temperature-induced frequency change rates of the reference cavity; determining a first temperature gradient between the measurement cavity and the copper cavity, and determining a second temperature gradient between the reference cavity and the copper cavity. The above scheme obtains the temperature gradient between the FP resonant cavity and the copper cavity by fitting the sample data and calculation, thereby correcting the actual temperature of the gas in the FP resonant cavity according to the temperature gradient, and improving the accuracy of substituting the gas temperature into the correlation relationship to measure the pressure.

Description

Technical Field

[0001] This application relates to the field of optical pressure measurement technology, and in particular to a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity. Background Technology

[0002] Pressure is a commonly used measurement parameter in industrial production and scientific research, and pressure testing is conducted through a unified pressure standard. Based on the Fabry-Perot (FP) resonator, an optical pressure standard combines gas thermodynamics equations and the Lorentz-Lorenz equation to establish the correlation between gas pressure and its refractive index. By measuring the change in laser resonant frequency under different gas pressures in the FP resonator, the pressure of the gas filling the FP resonator can be determined. This allows the pressure value to be traced back to fundamental physical constants (such as the Boltzmann constant) and basic physical properties of the gas (such as polarizability or magnetic susceptibility). This method offers the advantage of high measurement accuracy and represents a trend towards ultra-precision pressure measurement.

[0003] In practical applications, the FP resonant cavity is connected to an external copper cavity for temperature control. The temperature of the gas in the FP resonant cavity is controlled by a temperature control module connected to the copper cavity. This temperature is then substituted into the relationship between gas pressure and refractive index to obtain the pressure of the gas to be measured in the FP resonant cavity.

[0004] However, a temperature gradient exists between the FP resonant cavity and the copper cavity, causing an error between the temperature controlled by the temperature control module and the actual temperature of the gas in the FP resonant cavity. This results in low accuracy when using correlation to measure pressure. Summary of the Invention

[0005] This application provides a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, in order to improve the accuracy of pressure testing.

[0006] In a first aspect, this application provides a method for measuring the temperature gradient between an optical pressure standard FP resonator and a temperature-controlled copper cavity, comprising: determining sample data, wherein the sample data includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures, the sample data being obtained by stepping the temperature of the Fabry-Perot FP resonator and measuring the frequency, the FP resonator including a measurement cavity and a reference cavity; performing fitting processing on the sample data to obtain a first frequency change coefficient of the frequency change of the measurement cavity as a function of temperature, and a second frequency change coefficient of the frequency change of the reference cavity as a function of temperature; and performing a method for measuring the temperature gradient between the first frequency change coefficient and the second frequency change coefficient ... Based on the coefficient of thermal expansion and the plurality of target temperatures, a plurality of first thermal expansion coefficients of the measuring cavity are determined; based on the second frequency variation coefficient and the plurality of target temperatures, a plurality of second thermal expansion coefficients of the reference cavity are determined; based on the plurality of first thermal expansion coefficients, a plurality of first temperature-induced frequency variation rates of the measuring cavity are determined; based on the plurality of second thermal expansion coefficients, a plurality of second temperature-induced frequency variation rates of the reference cavity are determined; based on the plurality of first temperature-induced frequency variation rates, a first temperature gradient between the measuring cavity and the copper cavity is determined; based on the plurality of second temperature-induced frequency variation rates, a second temperature gradient between the reference cavity and the copper cavity is determined.

[0007] In one possible implementation, determining sample data includes: determining a first initial temperature of the inner heating layer and a second initial temperature of the outer heating layer, wherein the inner and outer heating layers are used to control the temperature environment of the FP resonant cavity, and the copper cavity includes the inner and outer heating layers; evacuating the pressure chamber until the current vacuum level of the FP resonant cavity is greater than or equal to a vacuum level threshold, obtaining a first initial frequency of the measurement cavity and a second initial frequency of the reference cavity, wherein the pressure chamber is used to control the pressure environment of the FP resonant cavity; filling the pressure chamber with a preset gas at a preset pressure, adjusting the temperatures of the inner and outer heating layers according to a target step temperature, and obtaining multiple first real-time frequencies of the measurement cavity and multiple second real-time frequencies of the reference cavity after each temperature adjustment; determining the multiple first frequency changes based on the first initial frequency and the multiple first real-time frequencies, and determining the multiple second frequency changes based on the second initial frequency and the multiple second real-time frequencies; determining that the sample data includes the first initial temperature, the second initial temperature, the target step temperature, the multiple first frequency changes, and the multiple second frequency changes.

[0008] In one possible implementation, the target step temperature includes a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature; adjusting the temperature of the inner heating layer and the outer heating layer according to the target step temperature includes: performing step heating treatment on the inner heating layer according to the first step temperature until the temperature of the inner heating layer reaches a first temperature threshold; performing step heating treatment on the outer heating layer according to the second step temperature until the temperature of the outer heating layer reaches a second temperature threshold; performing step cooling treatment on the inner heating layer according to the first step temperature until the temperature of the inner heating layer reaches a first initial temperature; and performing step cooling treatment on the inner heating layer according to the second step temperature until the temperature of the inner heating layer reaches a first initial temperature. The temperature of the outer heating layer is gradually decreased until it reaches the second initial temperature. The inner heating layer is gradually heated according to the third temperature step until it reaches the first temperature threshold. The outer heating layer is gradually heated according to the fourth temperature step until it reaches the second temperature threshold. The inner heating layer is gradually decreased according to the third temperature step until it reaches the first initial temperature. The outer heating layer is gradually decreased according to the fourth temperature step until it reaches the second initial temperature.

[0009] In one possible implementation, obtaining multiple first real-time frequencies of the measuring cavity and multiple second real-time frequencies of the reference cavity after each temperature adjustment includes: determining the real-time temperature using a standard thermometer in the pressure chamber after each temperature adjustment; if the fluctuation value of the real-time temperature within a preset time period is less than a fluctuation value threshold, then obtaining a first beat frequency between the measuring cavity and the reference cavity, and a second beat frequency between the reference cavity and the laser; determining the multiple first real-time frequencies based on the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser; and determining the multiple second real-time beat frequencies based on the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser.

[0010] In one possible implementation, the sample data is fitted to obtain a first frequency change coefficient for the frequency change of the measurement cavity as a function of temperature, and a second frequency change coefficient for the frequency change of the reference cavity as a function of temperature. This includes: determining a first correction frequency and a second correction frequency based on the gas pressure change introduced by the vacuum exhaust effect, the FP cavity deformation coefficient, and the cavity mirror reflection phase shift correction coefficient; correcting the plurality of first frequency changes using the first correction frequency to obtain a plurality of first target frequency changes; correcting the plurality of second frequency changes using the second correction frequency to obtain a plurality of second target frequency changes; and fitting the plurality of target temperatures, the plurality of first target frequency changes, and the plurality of second target frequency changes to obtain the first frequency change coefficient and the second frequency change coefficient.

[0011] In one possible implementation, determining a plurality of first temperature-induced frequency change rates of the measurement cavity based on the plurality of first thermal expansion coefficients, and determining a plurality of second temperature-induced frequency change rates of the reference cavity based on the plurality of second thermal expansion coefficients, includes: determining the absolute frequency of the iodine-stabilized He-Ne laser; calculating the negative of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the plurality of first temperature-induced frequency change rates; and calculating the negative of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the plurality of second temperature-induced frequency change rates.

[0012] In one possible implementation, determining a first temperature gradient between the measurement cavity and the copper cavity based on the plurality of first temperature-induced frequency change rates, and determining a second temperature gradient between the reference cavity and the copper cavity based on the plurality of second temperature-induced frequency change rates, includes: receiving a measurement request, the measurement request including a first current temperature of the measurement cavity, a first current frequency change of the measurement cavity, a second current temperature of the reference cavity, and a second current frequency change of the reference cavity; determining a first target temperature-induced frequency change rate corresponding to the first current temperature, and determining a second target temperature-induced frequency change rate corresponding to the second current temperature; determining the ratio of the first current frequency change to the first target temperature-induced frequency change rate as the first temperature gradient, and determining the ratio of the second current frequency change to the second target temperature-induced frequency change rate as the second temperature gradient.

[0013] Secondly, this application provides a temperature gradient measurement system between an optical pressure standard FP resonator and a temperature-controlled copper cavity, comprising: a determination module, used to determine sample data, the sample data including multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures, the sample data being obtained by stepping temperature adjustment and frequency measurement of the Fabry-Perot FP resonator, the FP resonator including a measurement cavity and a reference cavity; a fitting module, used to perform fitting processing on the sample data to obtain a first frequency change coefficient of the frequency change of the measurement cavity with temperature change and a second frequency change coefficient of the frequency change of the reference cavity with temperature change; and a first calculation module, used to calculate based on the first frequency change coefficient of the measurement cavity with temperature change and a second frequency change coefficient of the reference cavity with temperature change. A second calculation module is used to determine multiple first thermal expansion coefficients of the measuring cavity based on a frequency change coefficient and the multiple target temperatures, and to determine multiple second thermal expansion coefficients of the reference cavity based on the multiple first thermal expansion coefficients and the multiple target temperatures; a third processing module is used to determine a first temperature gradient between the measuring cavity and the copper cavity based on the multiple first temperature-induced frequency change rates, and to determine a second temperature gradient between the reference cavity and the copper cavity based on the multiple second temperature-induced frequency change rates.

[0014] In one possible implementation, the determining module is specifically used to determine a first initial temperature of the inner heating layer and a second initial temperature of the outer heating layer. The inner heating layer and the outer heating layer are used to control the temperature environment of the FP resonant cavity. The copper cavity includes the inner heating layer and the outer heating layer. The determining module is also specifically used to evacuate the pressure chamber until the current vacuum level of the FP resonant cavity is greater than or equal to a vacuum level threshold, and to obtain a first initial frequency of the measuring cavity and a second initial frequency of the reference cavity. The pressure chamber is used to control the pressure environment of the FP resonant cavity. The determining module is also specifically used to fill the pressure chamber with a preset gas at a preset pressure. The inner heating layer and the outer heating layer are adjusted according to the target step temperature. After each temperature adjustment, the frequency is obtained to obtain multiple first real-time frequencies of the measuring cavity and multiple second real-time frequencies of the reference cavity. The determining module is further configured to determine the multiple first frequency changes based on the first initial frequency and the multiple first real-time frequencies, and to determine the multiple second frequency changes based on the second initial frequency and the multiple second real-time frequencies. The determining module is further configured to determine that the sample data includes the first initial temperature, the second initial temperature, the target step temperature, the multiple first frequency changes, and the multiple second frequency changes.

[0015] In one possible implementation, the target step temperature includes a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature; the determining module is specifically configured to perform step heating treatment on the inner heating layer according to the first step temperature until the temperature of the inner heating layer reaches a first temperature threshold, and perform step heating treatment on the outer heating layer according to the second step temperature until the temperature of the outer heating layer reaches a second temperature threshold; the determining module is further configured to perform step cooling treatment on the inner heating layer according to the first step temperature until the temperature of the inner heating layer reaches the first initial temperature, and perform step cooling treatment on the outer heating layer according to the second step temperature. The process continues until the temperature of the outer heating layer reaches the second initial temperature. Specifically, the determining module is further configured to perform step heating on the inner heating layer according to the third step temperature until the temperature of the inner heating layer reaches the first temperature threshold, and to perform step heating on the outer heating layer according to the fourth step temperature until the temperature of the outer heating layer reaches the second temperature threshold. The determining module is also specifically configured to perform step cooling on the inner heating layer according to the third step temperature until the temperature of the inner heating layer reaches the first initial temperature, and to perform step cooling on the outer heating layer according to the fourth step temperature until the temperature of the outer heating layer reaches the second initial temperature.

[0016] In one possible implementation, the determining module is specifically configured to determine the real-time temperature using a standard thermometer in the pressure chamber after each temperature adjustment; the determining module is further configured to, if the fluctuation value of the real-time temperature within a preset time period is less than a fluctuation value threshold, obtain a first beat frequency between the measuring cavity and the reference cavity, and a second beat frequency between the reference cavity and the laser; the determining module is further configured to, based on the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser, determine the plurality of first real-time frequencies, and based on the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser, determine the plurality of second real-time beat frequencies.

[0017] In one possible implementation, the system further includes: a correction module, configured to determine a first correction frequency and a second correction frequency based on the gas pressure change introduced by the vacuum exhaust effect, the FP cavity deformation coefficient, and the cavity mirror reflection phase shift correction coefficient; the correction module is further configured to correct the plurality of first frequency changes using the first correction frequency to obtain a plurality of first target frequency changes, and to correct the plurality of second frequency changes using the second correction frequency to obtain a plurality of second target frequency changes; the correction module is further configured to perform fitting processing on the plurality of target temperatures, the plurality of first target frequency changes, and the plurality of second target frequency changes to obtain the first frequency change coefficient and the second frequency change coefficient.

[0018] In one possible implementation, the system further includes: an execution module for determining the absolute frequency of the iodine-stabilized He-Ne laser; the execution module is further configured to calculate the negative of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the plurality of first temperature-induced frequency change rates, and to calculate the negative of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the plurality of second temperature-induced frequency change rates.

[0019] In one possible implementation, the system further includes: a measurement module, configured to receive a measurement request, the measurement request including a first current temperature of the measurement cavity, a first current frequency change of the measurement cavity, a second current temperature of the reference cavity, and a second current frequency change of the reference cavity; the measurement module is further configured to determine a first target temperature-induced frequency change rate corresponding to the first current temperature, and to determine a second target temperature-induced frequency change rate corresponding to the second current temperature; the measurement module is further configured to determine the ratio of the first current frequency change to the first target temperature-induced frequency change rate as the first temperature gradient, and to determine the ratio of the second current frequency change to the second target temperature-induced frequency change rate as the second temperature gradient.

[0020] Thirdly, this application provides an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method described in any one of the first aspects.

[0021] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which are executed by a processor as described in any one of the first aspects.

[0022] Fifthly, this application provides a computer program product including a computer program that is executed by a processor as described in any one of the first aspects.

[0023] This application provides a method for measuring the temperature gradient between an optical pressure standard FP resonator and a temperature-controlled copper cavity. The method includes: determining sample data, which includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures. The sample data is obtained by stepping the temperature of the Fabry-Perot FP resonator and measuring its frequency. The FP resonator includes a measurement cavity and a reference cavity. The method further involves fitting the sample data to obtain a first frequency change coefficient for the frequency change of the measurement cavity as a function of temperature, and a second frequency change coefficient for the frequency change of the reference cavity as a function of temperature. Based on the first frequency change coefficient... Based on the number of data points and the multiple target temperatures, multiple first thermal expansion coefficients of the measuring cavity are determined. Based on the second frequency variation coefficient and the multiple target temperatures, multiple second thermal expansion coefficients of the reference cavity are determined. Based on the multiple first thermal expansion coefficients, multiple first temperature-induced frequency variation rates of the measuring cavity are determined. Based on the multiple second thermal expansion coefficients, multiple second temperature-induced frequency variation rates of the reference cavity are determined. Based on the multiple first temperature-induced frequency variation rates, a first temperature gradient between the measuring cavity and the copper cavity is determined. Based on the multiple second temperature-induced frequency variation rates, a second temperature gradient between the reference cavity and the copper cavity is determined. This scheme obtains the temperature gradient between the FP resonant cavity and the copper cavity by fitting and calculating sample data. The actual temperature of the gas in the FP resonant cavity is then corrected based on the temperature gradient, thereby improving the accuracy of measuring pressure by incorporating temperature into the correlation relationship. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0025] Figure 1 A schematic diagram illustrating an application scenario for a method of measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, provided in an embodiment of this application.

[0026] Figure 2 A schematic flowchart illustrating a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, provided for an embodiment of this application;

[0027] Figure 3 A schematic flowchart illustrating a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, provided for an embodiment of this application;

[0028] Figure 4A schematic diagram illustrating the step temperature adjustment of the inner heating layer provided in an embodiment of this application;

[0029] Figure 5 A schematic diagram illustrating the determination of the coefficient of thermal expansion provided in an embodiment of this application;

[0030] Figure 6 A schematic diagram illustrating the determination of the temperature-induced frequency change rate provided in an embodiment of this application;

[0031] Figure 7 A schematic diagram of a temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in this application embodiment;

[0032] Figure 8 A schematic diagram of a temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in this application embodiment;

[0033] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0034] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0035] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of systems and methods consistent with some aspects of this application as detailed in the appended claims.

[0036] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use, processing, transmission, provision, disclosure, and application of the relevant data all comply with the relevant laws, regulations, and standards of the relevant countries and regions, have taken necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation portals for users to choose to authorize or refuse.

[0037] It should be noted that the temperature gradient measurement method between the optical pressure standard FP resonant cavity and the temperature-controlled copper cavity of this application can be used in the field of optical pressure measurement technology, and can also be used in any field other than optical pressure measurement. The application field of the temperature gradient measurement method between the optical pressure standard FP resonant cavity and the temperature-controlled copper cavity of this application is not limited.

[0038] Figure 1 This illustration illustrates an application scenario for a method to measure the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, as provided in this application embodiment. The optical pressure standard includes a temperature control system, an optical path system, and dual FP cavities. The temperature control system comprises a copper cavity, inner and outer aluminum heating layers, and an external water circulation layer. The temperature control system is used for temperature control, and the inner and outer aluminum heating layers are controlled by a temperature controller. A pressure chamber, located in the center of the temperature control system, is used for pressure control. The gas to be measured is introduced into the FP resonant cavity, and four standard platinum resistance thermometers (SPRTs) are placed at the four corners of the pressure chamber for temperature measurement. A laser source emits a laser beam that passes through the FP resonant cavity to reach the detector. The pressure of the gas to be measured is obtained by substituting the frequency change detected by the detector and the measured temperature of the standard platinum resistance thermometers into a correlation relationship. The CDG is a thin-film capacitive pressure gauge, and the value displayed by the CDG characterizes the amount of gas pressure change introduced by the vacuum exhaust effect.

[0039] In practical applications, the FP resonant cavity is used for measurement under background vacuum conditions. Under background vacuum conditions, thermal conduction is weak, and the thermal link between the FP resonant cavity and the copper cavity is broken, resulting in a temperature gradient between the FP resonant cavity and the copper cavity. That is, the measured temperature of the standard platinum resistance thermometer fails to reflect the actual temperature of the gas in the FP resonant cavity, resulting in low accuracy of pressure measurement.

[0040] The method for measuring the temperature gradient between the optical pressure standard FP resonant cavity and the temperature-controlled copper cavity provided in this application aims to solve the above-mentioned technical problems in the prior art.

[0041] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0042] Figure 2 A flowchart illustrating a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, provided in this application embodiment, includes the following steps:

[0043] S201. Determine the sample data, which includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures.

[0044] The sample data was obtained by stepping the temperature of the Fabry-Perot (FP) resonator and measuring its frequency. The FP resonator includes a measurement cavity and a reference cavity.

[0045] For example, the measuring chamber is a chamber through which the pressure of the gas to be measured is introduced, and the reference chamber is a chamber that provides a frequency reference. A first frequency change corresponds to the measuring chamber, and a second frequency change corresponds to the reference chamber.

[0046] Using a scenario example, the frequencies of the measurement cavity and the reference cavity are measured separately. The frequency at the initial temperature and the frequency at each target temperature are measured, and the frequency change is determined based on the change in frequency at each target temperature compared to the frequency at the initial temperature.

[0047] S202. Fit the sample data to obtain the first frequency change coefficient of the frequency change of the measuring cavity as a function of temperature, and the second frequency change coefficient of the frequency change of the reference cavity as a function of temperature.

[0048] For example, a suitable function model is determined based on the relationship between frequency change and temperature, and then fitted using statistical methods such as least squares to obtain the parameters in the function model, namely the first frequency change coefficient and the second frequency change coefficient.

[0049] Optionally, the sample data can be divided into a test set and a validation set. The function can be obtained by fitting the test set, and the function can be validated by the validation set.

[0050] S203. Based on the first frequency variation coefficient and multiple target temperatures, determine multiple first thermal expansion coefficients of the measuring cavity, and based on the second frequency variation coefficient and multiple target temperatures, determine multiple second thermal expansion coefficients of the reference cavity.

[0051] The coefficient of thermal expansion (CTE) of an FP resonant cavity represents the rate of change of the cavity's dimensions with temperature variations. For an FP resonant cavity, the CTE affects the cavity's length, which in turn affects the optical standing wave modes within the cavity, ultimately influencing the FP resonant cavity's resonant frequency.

[0052] For example, by acquiring sample data from an optical pressure standard for measurement, in-situ measurement of the gas temperature in the FP resonant cavity of an optical pressure standard temperature control system can be achieved, thereby improving the accuracy of gas pressure measurement.

[0053] S204. Based on multiple first thermal expansion coefficients, determine multiple first temperature-induced frequency change rates of the measuring cavity, and based on multiple second thermal expansion coefficients, determine multiple second temperature-induced frequency change rates of the reference cavity.

[0054] Among them, the temperature-induced frequency change rate represents how the frequency of the FP resonant cavity changes with temperature.

[0055] For example, there is a direct relationship between the coefficient of thermal expansion and the temperature-induced frequency change rate. The coefficient of thermal expansion describes the rate of change of the length of the FP resonant cavity when the temperature changes, while the temperature-induced frequency change rate reflects the effect of the change in the length of the FP resonant cavity on the frequency. The length of the FP resonant cavity determines the resonant frequency of light. When the temperature changes, the length of the FP resonant cavity changes, which in turn causes a change in the resonant frequency of the light inside the cavity. Therefore, the temperature-induced frequency change rate can be regarded as a comprehensive reflection of the relationship between the coefficient of thermal expansion and the length of the FP resonant cavity and the frequency.

[0056] S205. Based on multiple first temperature-induced frequency change rates, determine the first temperature gradient between the measuring cavity and the copper cavity; based on multiple second temperature-induced frequency change rates, determine the second temperature gradient between the reference cavity and the copper cavity.

[0057] The first temperature gradient reflects the temperature difference between the measuring cavity and the copper cavity. The second temperature gradient reflects the temperature difference between the reference cavity and the copper cavity. By using the first temperature gradient, the second temperature gradient, and the temperature of the copper cavity, the actual temperature of the gas in the measuring cavity and the actual temperature of the gas in the reference cavity can be determined.

[0058] With the example of a scenario, this application measures the temperature gradient between the FP resonant cavity and the temperature-controlled copper cavity before performing pressure measurement using an optical pressure standard. During pressure measurement, the temperature gradient correction is used to obtain a more accurate temperature of the gas in the FP resonant cavity, thereby improving the accuracy of pressure measurement.

[0059] The method for measuring the temperature gradient between an optical pressure standard FP resonator and a temperature-controlled copper cavity provided in this application includes: determining sample data, which includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures. The sample data is obtained by stepping the temperature of the Fabry-Perot FP resonator and measuring the frequency. The FP resonator includes a measurement cavity and a reference cavity. The sample data is fitted to obtain a first frequency change coefficient of the measurement cavity's frequency change with temperature and a second frequency change coefficient of the reference cavity's frequency change with temperature. Based on the first frequency change coefficients and multiple target temperatures, multiple first thermal expansion coefficients of the measurement cavity are determined. Based on the second frequency change coefficients and multiple target temperatures, multiple second thermal expansion coefficients of the reference cavity are determined. Based on the multiple first thermal expansion coefficients, multiple first temperature-induced frequency change rates of the measurement cavity are determined. Based on the multiple second thermal expansion coefficients, multiple second temperature-induced frequency change rates of the reference cavity are determined. Based on the multiple first temperature-induced frequency change rates, a first temperature gradient between the measurement cavity and the copper cavity is determined. Based on the multiple second temperature-induced frequency change rates, a second temperature gradient between the reference cavity and the copper cavity is determined. The above scheme obtains the temperature gradient between the FP resonant cavity and the copper cavity by fitting and calculating the sample data. The actual temperature of the gas in the FP resonant cavity is then corrected based on the temperature gradient, thereby improving the accuracy of measuring pressure by substituting the gas temperature into the correlation relationship.

[0060] Based on any of the above embodiments, the following, in conjunction with Figure 3 The detailed process of measuring the temperature gradient between the optical pressure standard FP resonant cavity and the temperature-controlled copper cavity is explained.

[0061] Figure 3 This is a schematic flowchart illustrating a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, provided as an embodiment of this application. Figure 3 As shown, the method includes:

[0062] S301. Determine the first initial temperature of the inner heating layer and the second initial temperature of the outer heating layer.

[0063] The inner heating layer and the outer heating layer are used to control the temperature environment of the FP resonant cavity. The copper cavity includes an inner heating layer and an outer heating layer.

[0064] For example, the inner heating layer is closer to the FP resonant cavity. By having the inner and outer heating layers work together, the temperature of the FP resonant cavity can be better controlled, the impact of external environmental changes on the FP resonant cavity temperature can be reduced, and the thermal stability of the system can be improved.

[0065] S302. Evacuate the pressure chamber until the current vacuum level of the FP resonant cavity is greater than or equal to the vacuum level threshold, and obtain the first initial frequency of the measurement cavity and the second initial frequency of the reference cavity.

[0066] The pressure chamber is used to control the pressure environment of the FP resonant cavity.

[0067] For example, the pressure chamber is located outside the FP resonant cavity and inside the copper cavity. The pressure chamber is connected to a vacuum pump, and gas can be filled into or extracted from the pressure chamber to achieve a specified pressure environment.

[0068] With the example scenario, the vacuum threshold is 10. -4 On the order of magnitude, when the current vacuum level of the FP resonant cavity reaches 10 -4 If the magnitude reaches a certain level, then vacuuming will stop.

[0069] S303. Inject a preset gas at a preset pressure into the pressure chamber, adjust the temperature of the inner heating layer and the outer heating layer according to the target step temperature, and obtain multiple first real-time frequencies of the measuring cavity and multiple second real-time frequencies of the reference cavity after each temperature adjustment.

[0070] Using a scenario example, after reaching the vacuum threshold, close the vacuum valve to stop evacuation. Then, fill the pressure chamber with 100Pa of high-purity nitrogen.

[0071] For example, the thermal conductivity of a gas is related to pressure and temperature, increasing with increasing pressure. When the pressure is below 100 Pa, the thermal conductivity increases linearly with pressure; when the pressure is above 100 Pa, the thermal conductivity increases by 1% for every 100 kPa of pressure. Therefore, when the gas pressure is above 100 Pa, the change in gas thermal conductivity due to pressure variation is negligible. Thus, measuring the optical pressure standard thermal expansion coefficient under a 100 Pa gas pressure avoids the temperature gradient between the FP resonant cavity and the temperature-controlled copper cavity under a base vacuum, while also reducing the time required for the vacuuming process.

[0072] One feasible implementation method involves setting the target step temperature to include a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature. The temperatures of the inner and outer heating layers can be adjusted as follows: The inner heating layer is stepped-heated according to the first step temperature until it reaches a first temperature threshold; the outer heating layer is stepped-heated according to the second step temperature until it reaches a second temperature threshold; the inner heating layer is stepped-cooled according to the first step temperature until it reaches a first initial temperature; the outer heating layer is stepped-cooled according to the second step temperature until it reaches a second initial temperature; the inner heating layer is stepped-heated according to the third step temperature until it reaches the first temperature threshold; the outer heating layer is stepped-heated according to the fourth step temperature until it reaches the second temperature threshold; the inner heating layer is stepped-cooled according to the third step temperature until it reaches the first initial temperature; the outer heating layer is stepped-cooled according to the fourth step temperature until it reaches the second initial temperature.

[0073] Optionally, the first step temperature is greater than the second step temperature, and the third step temperature is greater than the fourth step temperature.

[0074] Using a scenario example, adjusting the temperature in steps one and two yields sample data with wider intervals, while adjusting it in steps three and four yields sample data with narrower intervals. Using the wider-interval sample data establishes an initial fit and establishes a correlation, while using the narrower-interval sample data for optimization improves the accuracy of the correlation.

[0075] Below, in conjunction with Figure 4 The step temperature adjustment of the inner heating layer is explained.

[0076] Figure 4 This is a schematic diagram illustrating the step temperature adjustment of the inner heating layer provided in an embodiment of this application. Figure 4 As shown, taking the inner heating layer as an example, T1 is the first step temperature and T3 is the third step temperature. The step temperature adjustment includes: gradually increasing the temperature from the initial temperature to the temperature threshold according to the first step temperature, gradually decreasing the temperature from the temperature threshold to the initial temperature according to the first step temperature, gradually increasing the temperature from the initial temperature to the temperature threshold according to the third step temperature, and gradually decreasing the temperature from the temperature threshold to the initial temperature according to the third step temperature.

[0077] It should be noted that the step temperature adjustment method for the outer heating layer is similar to that for the inner heating layer.

[0078] In this feasible implementation, multiple data points can be obtained through cyclic heating and cooling, thereby increasing the number of sample data and improving the accuracy of the fit.

[0079] One feasible implementation method is to obtain the first real-time frequency and the second real-time frequency by means of the following: after each temperature adjustment, the real-time temperature is determined by a standard thermometer in the pressure chamber; if the fluctuation value of the real-time temperature within a preset time period is less than the fluctuation value threshold, the first beat frequency between the measuring cavity and the reference cavity and the second beat frequency between the reference cavity and the laser are obtained; based on the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser, multiple first real-time frequencies are determined, and based on the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser, multiple second real-time beat frequencies are determined.

[0080] Wherein, the first real-time frequency is the absolute frequency of the measurement cavity, and the second real-time frequency is the absolute frequency of the reference cavity. The beat frequency is the frequency difference; the first beat frequency is the frequency difference between the measurement cavity and the reference cavity, and the second beat frequency is the frequency difference between the reference cavity and the laser.

[0081] Optionally, the standard thermometer in the pressure chamber is a standard platinum resistance thermometer.

[0082] To illustrate with a scenario example, after each temperature adjustment, the real-time temperature of a standard thermometer is obtained. If the fluctuation value of the real-time temperature within 5 seconds is less than 1mK, it indicates that the FP resonant cavity has reached thermal equilibrium. Testing and obtaining the beat frequency can improve the accuracy of the beat frequency.

[0083] For example, the sum of the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser is determined as the first real-time frequency, and the sum of the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser is determined as the second real-time frequency.

[0084] In this feasible implementation, the beat frequency can be quickly acquired using a laser and a photodetector, and the real-time frequency can be indirectly measured using the beat frequency, thereby increasing the measurement frequency range.

[0085] S304. Based on the first initial frequency and multiple first real-time frequencies, determine multiple first frequency changes; based on the second initial frequency and multiple second real-time frequencies, determine multiple second frequency changes.

[0086] With the example of the scenario, the first initial frequency is The first real-time frequency is First frequency change The second initial frequency is The second real-time frequency is Second frequency change

[0087] For example, each first frequency change corresponds to a first real-time frequency and a target temperature, and each second frequency change corresponds to a second real-time frequency and a target temperature, thereby obtaining sample data containing multiple target temperatures, multiple first frequency changes, and multiple second frequency changes.

[0088] S305. The sample data includes a first initial temperature, a second initial temperature, a target step temperature, multiple first frequency changes, and multiple second frequency changes.

[0089] For example, based on a first initial temperature and a second initial temperature, multiple measurement frequencies are obtained by sequentially increasing the target step temperature, where the target temperature includes the temperature.

[0090] Optionally, the step temperature can be determined based on the required fitting accuracy.

[0091] Using scenario examples, it's clear that within a certain range, a smaller step temperature results in denser sample data and more accurate fitted parameters. However, beyond a certain range, a smaller step temperature increases the likelihood of overfitting. Therefore, it's crucial to determine the correlation between step temperature and fitting accuracy, and then select an appropriate step temperature based on the required fitting accuracy and this correlation.

[0092] S306. Determine the first correction frequency and the second correction frequency based on the gas pressure change introduced by the vacuum exhaust effect, the FP cavity deformation coefficient, and the cavity mirror reflection phase shift correction coefficient.

[0093] The first correction frequency is used to correct the first frequency change, and the second correction frequency is used to correct the second frequency change.

[0094] With the aid of scenario examples, gas molecules adsorbed on the surfaces of the vacuum chamber and seals will be released outwards under non-evacuation conditions, causing a decrease in the purity of the filling gas and pressure measurement drift. In the process of determining the thermal expansion coefficient of the optical pressure standard, the effect of vacuum venting on pressure measurement cannot be completely ignored. Furthermore, during the filling and discharging process of the FP resonant cavity, the slight deformation of the high-reflectivity mirror causes measurement frequency drift, especially for the reference cavity which is under background vacuum internally and under gas pressure externally. Therefore, frequency correction can improve the accuracy of gas pressure measurement.

[0095] For example, the formula for calculating the first correction frequency is shown in formula (1), and the formula for calculating the second correction frequency is shown in formula (2):

[0096]

[0097] Δυ RC,p =Δp×d r ×υp / (1+ε α (2)

[0098] Where Δp represents the change in gas pressure, R is the gas constant, and υ p Indicates the pressure of the filled gas, d r The deformation coefficient of the reference cavity is T, where T is the gas thermodynamic temperature, and d is the reference cavity deformation coefficient. m It is the deformation coefficient of the measuring cavity, ε α A represents the phase shift correction factor for the laparoscope reflection. mix The effective molar polarizability of impurity gases generated by the vacuum exhaust effect.

[0099] S307. Correct multiple first frequency changes using a first correction frequency to obtain multiple first target frequency changes, and correct multiple second frequency changes using a second correction frequency to obtain multiple second target frequency changes.

[0100] With the example of the scenario, for each first frequency change, the corresponding first target frequency change is obtained by subtracting the first correction frequency; for each second frequency change, the corresponding second target frequency change is obtained by subtracting the second correction frequency.

[0101] S308. Fit multiple target temperatures, multiple first target frequency changes, and multiple second target frequency changes to obtain the first frequency change coefficient and the second frequency change coefficient.

[0102] For example, fitting is performed based on formulas (3) and (4):

[0103]

[0104] Where, Δυ MC Let υ be the first frequency change, υ be the absolute frequency of the iodine-stabilized He-Ne laser, a0, a1, a2 be the first frequency change coefficients, a3, a4, a5 be the second frequency change coefficients, and T be the second frequency change coefficient. 90 Ti is the target temperature, and Ti0 is the initial temperature.

[0105] With the help of scenario examples, it can be shown that by correcting the first and second target frequency changes, the error can be effectively reduced, thereby improving the accuracy of the first and second frequency change coefficients.

[0106] S309. Based on the first frequency variation coefficient and multiple target temperatures, determine multiple first thermal expansion coefficients of the measuring cavity, and based on the second frequency variation coefficient and multiple target temperatures, determine multiple second thermal expansion coefficients of the reference cavity.

[0107] Each target temperature corresponds to a first coefficient of thermal expansion, and each target temperature corresponds to a second coefficient of thermal expansion.

[0108] For example, the first thermal expansion coefficient of the measuring cavity is calculated using formula (5):

[0109] α(T 90 )=a1+a2(T 90 -Ti0)·············(5)

[0110] Wherein, α(T) 90 ) represents T 90 The first coefficient of thermal expansion at temperature. a0 and a1 are obtained by fitting the formula (3).

[0111] It should be noted that the calculation method for the second thermal expansion coefficient is the same, and will not be repeated here.

[0112] Below, in conjunction with Figure 5 The determination of the coefficient of thermal expansion is explained.

[0113] Figure 5 This is a schematic diagram illustrating the determination of the coefficient of thermal expansion as provided in an embodiment of this application. Figure 5 As shown, the frequency change coefficient is obtained by fitting the sample data. The first correspondence is established based on the frequency change coefficient, i.e., formula (5). The thermal expansion coefficient corresponding to any current temperature is obtained by substituting any current temperature into the first correspondence.

[0114] S310. Based on multiple first thermal expansion coefficients, determine multiple first temperature-induced frequency change rates of the measuring cavity; based on multiple second thermal expansion coefficients, determine multiple second temperature-induced frequency change rates of the reference cavity.

[0115] One feasible implementation method is to determine the first temperature-induced frequency change rate and the second temperature-induced frequency change rate by: determining the absolute frequency of the iodine-stabilized He-Ne laser; calculating the negative of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain multiple first temperature-induced frequency change rates; and calculating the negative of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain multiple second temperature-induced frequency change rates.

[0116] For example, the first temperature-induced frequency change rate of the measuring cavity is calculated using formula (6):

[0117]

[0118] in, The first temperature-induced frequency change rate of the measuring cavity.

[0119] With the help of scenario examples, the rate of change of frequency due to temperature means the speed at which a change in temperature causes a change in frequency. The rate of change of frequency due to temperature is used to establish the correspondence between temperature and the speed at which frequency changes.

[0120] It should be noted that the calculation method for the second temperature-induced frequency change rate is similar, and will not be repeated here.

[0121] Below, in conjunction with Figure 6 The determination of the rate of change of frequency due to temperature is explained.

[0122] Figure 6 This is a schematic diagram illustrating the determination of the coefficient of thermal expansion as provided in an embodiment of this application. Figure 6 As shown, the coefficient of thermal expansion corresponding to the current temperature is obtained by substituting any current temperature into the first correspondence. The coefficient of thermal expansion and the absolute frequency of the iodine-stabilized He-Ne laser are then substituted into the second correspondence, i.e., formula (6), to calculate the temperature-induced frequency change rate corresponding to the current temperature.

[0123] S311. Determine the first temperature gradient between the measuring cavity and the copper cavity based on multiple first temperature-induced frequency change rates, and determine the second temperature gradient between the reference cavity and the copper cavity based on multiple second temperature-induced frequency change rates.

[0124] With the help of scenario examples, multiple temperature-induced frequency change rates cover a variety of operating parameters. In practical applications, the corresponding temperature-induced frequency change rate is determined based on the actual operating parameters, and the corresponding temperature gradient is determined based on this.

[0125] One feasible implementation method is to determine the temperature gradient by: receiving a measurement request, the measurement request including a first current temperature of the measurement cavity, a first current frequency change of the measurement cavity, a second current temperature of the reference cavity, and a second current frequency change of the reference cavity; determining a first target temperature-induced frequency change rate corresponding to the first current temperature, and determining a second target temperature-induced frequency change rate corresponding to the second current temperature; determining the ratio of the first current frequency change to the first target temperature-induced frequency change rate as the first temperature gradient, and determining the ratio of the second current frequency change to the second target temperature-induced frequency change rate as the second temperature gradient.

[0126] The first and second current temperatures were measured using a standard thermometer.

[0127] With a scenario example, taking the measurement cavity as an example, the first thermal expansion coefficient corresponding to the first current temperature is determined based on the first current temperature and formula (5). Based on the first thermal expansion coefficient and formula (6), the corresponding first target temperature-induced frequency change rate is determined. The ratio of the first current frequency change to the first target temperature-induced frequency change rate is determined as the first temperature gradient corresponding to the measurement request.

[0128] It should be noted that the calculation method for the first temperature gradient is the same, and will not be repeated here.

[0129] In this feasible implementation, the temperature gradient can be accurately calculated by establishing the correlation between temperature and the coefficient of thermal expansion, and the correlation between the coefficient of thermal expansion and the rate of change of temperature-induced frequency.

[0130] Figure 7 This is a schematic diagram of a temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, provided as an embodiment of this application. Figure 7 As shown, the temperature gradient measurement 70 between the optical pressure standard FP resonant cavity and the temperature-controlled copper cavity may include: a determination module 71, a fitting module 72, a first calculation module 73, a second calculation module 74, and a processing module 75, wherein,

[0131] The determination module 71 is used to determine sample data, which includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures. The sample data is obtained by stepping the temperature of the Fabry-Perot FP resonator and measuring the frequency. The FP resonator includes a measurement cavity and a reference cavity.

[0132] The fitting module 72 is used to perform fitting processing on the sample data to obtain the first frequency change coefficient of the frequency change of the measurement cavity as a function of temperature, and the second frequency change coefficient of the frequency change of the reference cavity as a function of temperature.

[0133] The first calculation module 73 is used to determine multiple first thermal expansion coefficients of the measuring cavity based on the first frequency change coefficient and multiple target temperatures, and to determine multiple second thermal expansion coefficients of the reference cavity based on the second frequency change coefficient and multiple target temperatures.

[0134] The second calculation module 74 is used to determine multiple first temperature-induced frequency change rates of the measuring cavity based on multiple first thermal expansion coefficients, and to determine multiple second temperature-induced frequency change rates of the reference cavity based on multiple second thermal expansion coefficients.

[0135] The processing module 75 is used to determine a first temperature gradient between the measuring cavity and the copper cavity based on a plurality of first temperature-induced frequency change rates, and to determine a second temperature gradient between the reference cavity and the copper cavity based on a plurality of second temperature-induced frequency change rates.

[0136] Optionally, module 71 can be executed. Figure 2 S201 in the embodiment.

[0137] Optionally, the fitting module 72 can perform... Figure 2 S202 in the embodiment.

[0138] Optionally, the first calculation module 73 can execute Figure 2 S203 in the embodiment.

[0139] Optionally, the second calculation module 74 can execute Figure 2 S204 in the embodiment.

[0140] Optionally, processing module 75 can execute Figure 2 S205 in the embodiment.

[0141] It should be noted that the temperature gradient measurement system between the optical pressure standard FP resonant cavity and the temperature-controlled copper cavity shown in the embodiments of this application can execute the technical solution shown in the above method embodiments. Its implementation principle and beneficial effects are similar, and will not be repeated here.

[0142] In one possible implementation, the determining module 71 is specifically used for:

[0143] A first initial temperature of the inner heating layer is determined, and a second initial temperature of the outer heating layer is determined. The inner and outer heating layers are used to control the temperature environment of the FP resonant cavity. The copper cavity includes the inner heating layer and the outer heating layer.

[0144] The pressure chamber is evacuated until the current vacuum level of the FP resonant cavity is greater than or equal to the vacuum level threshold. The first initial frequency of the measurement cavity and the second initial frequency of the reference cavity are obtained. The pressure chamber is used to control the pressure environment of the FP resonant cavity.

[0145] Preset gas at a preset pressure is introduced into the pressure chamber. The temperature of the inner heating layer and the outer heating layer is adjusted according to the target step temperature. After each temperature adjustment, the frequency is obtained to obtain multiple first real-time frequencies of the measurement cavity and multiple second real-time frequencies of the reference cavity.

[0146] Based on the first initial frequency and multiple first real-time frequencies, multiple first frequency changes are determined, and based on the second initial frequency and multiple second real-time frequencies, multiple second frequency changes are determined.

[0147] The sample data includes a first initial temperature, a second initial temperature, a target step temperature, multiple first frequency changes, and multiple second frequency changes.

[0148] In one possible implementation, the target step temperature includes a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature; the determining module 71 is specifically used for:

[0149] The inner heating layer is subjected to step heating treatment according to the first step temperature until the temperature of the inner heating layer reaches the first temperature threshold. The outer heating layer is subjected to step heating treatment according to the second step temperature until the temperature of the outer heating layer reaches the second temperature threshold.

[0150] The inner heating layer is subjected to step cooling treatment based on the first step temperature until the temperature of the inner heating layer reaches the first initial temperature. The outer heating layer is subjected to step cooling treatment based on the second step temperature until the temperature of the outer heating layer reaches the second initial temperature.

[0151] The inner heating layer is heated stepwise according to the third step temperature until the temperature of the inner heating layer reaches the first temperature threshold. The outer heating layer is heated stepwise according to the fourth step temperature until the temperature of the outer heating layer reaches the second temperature threshold.

[0152] The inner heating layer is subjected to step cooling treatment according to the third step temperature until the temperature of the inner heating layer reaches the first initial temperature. The outer heating layer is subjected to step cooling treatment according to the fourth step temperature until the temperature of the outer heating layer reaches the second initial temperature.

[0153] In one possible implementation, the determining module 71 is specifically used for:

[0154] The real-time temperature is determined using a standard thermometer in the pressure chamber after each temperature adjustment.

[0155] If the fluctuation value of the real-time temperature within the preset time period is less than the fluctuation value threshold, then the first beat frequency between the measuring cavity and the reference cavity, and the second beat frequency between the reference cavity and the laser are obtained.

[0156] Multiple first real-time frequencies are determined based on the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser. Multiple second real-time beat frequencies are determined based on the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser.

[0157] Figure 8 This is a schematic diagram of a temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, provided as an embodiment of this application. Figure 7 Based on the illustrated embodiments, as Figure 8 As shown, the temperature gradient measurement system 80 between the optical pressure standard FP resonant cavity and the temperature-controlled copper cavity further includes: a correction module 76, an execution module 77, and a measurement module 78, wherein:

[0158] Correction module 76, used for:

[0159] The first correction frequency and the second correction frequency are determined based on the gas pressure change introduced by the vacuum gas release effect, the FP cavity deformation coefficient, and the cavity mirror reflection phase shift correction coefficient.

[0160] Multiple first frequency changes are corrected using a first correction frequency to obtain multiple first target frequency changes. Multiple second frequency changes are corrected using a second correction frequency to obtain multiple second target frequency changes.

[0161] The first frequency change coefficient and the second frequency change coefficient are obtained by fitting multiple target temperatures, multiple first target frequency changes, and multiple second target frequency changes.

[0162] Execution module 77 is used for:

[0163] Determine the absolute frequency of the iodine-stabilized He-Ne laser;

[0164] The negative of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser is calculated to obtain multiple first temperature-induced frequency change rates. The negative of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser is calculated to obtain multiple second temperature-induced frequency change rates.

[0165] Measurement module 78 is used for:

[0166] Receive a measurement request, which includes a first current temperature of the measurement cavity, a first current frequency change of the measurement cavity, a second current temperature of the reference cavity, and a second current frequency change of the reference cavity;

[0167] Determine the frequency change rate caused by the first target temperature corresponding to the first current temperature, and determine the frequency change rate caused by the second target temperature corresponding to the second current temperature.

[0168] The ratio of the first current frequency change to the first target temperature-induced frequency change rate is determined as the first temperature gradient, and the ratio of the second current frequency change to the second target temperature-induced frequency change rate is determined as the second temperature gradient.

[0169] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application, such as... Figure 9 As shown, the electronic device includes:

[0170] The electronic device includes a processor 291 and a memory 292; it may also include a communication interface 293 and a bus 294. The processor 291, memory 292, and communication interface 293 can communicate with each other via the bus 294. The communication interface 293 can be used for information transmission. The processor 291 can invoke logical instructions stored in the memory 292 to execute the methods of the above embodiments.

[0171] Furthermore, the logic instructions in the aforementioned memory 292 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0172] The memory 292, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this application. The processor 291 executes functional applications and data processing by running the software programs, instructions, and modules stored in the memory 292, thereby implementing the methods in the above-described method embodiments.

[0173] The memory 292 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 292 may include high-speed random access memory and may also include non-volatile memory.

[0174] This application provides a non-transitory computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods described in the foregoing embodiments.

[0175] This application provides a computer program product, including a computer program that, when executed by a processor, implements the method as described in the foregoing embodiments.

[0176] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0177] It should be further noted that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0178] It should be understood that the above system embodiments are merely illustrative, and the system of this application can also be implemented in other ways. For example, the division of units / modules in the above embodiments is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units, modules, or components can be combined, or integrated into another system, or some features can be ignored or not executed.

[0179] Furthermore, unless otherwise specified, the functional units / modules in the various embodiments of this application can be integrated into one unit / module, or each unit / module can exist physically separately, or two or more units / modules can be integrated together. The integrated units / modules described above can be implemented in hardware or as software program modules.

[0180] When the integrated unit / module is implemented in hardware, the hardware can be digital circuits, analog circuits, etc. The physical implementation of the hardware structure includes, but is not limited to, transistors, memristors, etc. The processor can be any suitable hardware processor, such as CPU, GPU, FPGA, DSP, and ASIC. The storage unit can be any suitable magnetic or magneto-optical storage medium, such as Resistive Random Access Memory (RRAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Enhanced Dynamic Random Access Memory (EDRAM), High-Bandwidth Memory (HBM), Hybrid Memory Cube (HMC), etc.

[0181] If the integrated unit / module is implemented as a software program module and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0182] In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0183] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0184] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, characterized in that, include: Determine sample data, which includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures. The sample data is obtained by stepping temperature adjustment and frequency measurement of the Fabry-Perot FP resonant cavity. The FP resonant cavity includes a measurement cavity and a reference cavity. The sample data is fitted to obtain a first frequency change coefficient of the frequency change of the measurement cavity as a function of temperature, and a second frequency change coefficient of the frequency change of the reference cavity as a function of temperature. Based on the first frequency change coefficient and the plurality of target temperatures, a plurality of first thermal expansion coefficients of the measuring cavity are determined, and based on the second frequency change coefficient and the plurality of target temperatures, a plurality of second thermal expansion coefficients of the reference cavity are determined. The first coefficient of thermal expansion satisfies the following formula: in, This represents the first coefficient of thermal expansion at the target temperature. and This represents the first frequency variation coefficient at the target temperature. Indicates the initial temperature; Based on the plurality of first thermal expansion coefficients, a plurality of first temperature-induced frequency change rates of the measuring cavity are determined, and based on the plurality of second thermal expansion coefficients, a plurality of second temperature-induced frequency change rates of the reference cavity are determined. The process of determining multiple first temperature-induced frequency change rates of the measurement cavity based on the multiple first thermal expansion coefficients and multiple second temperature-induced frequency change rates of the reference cavity based on the multiple second thermal expansion coefficients includes: determining the absolute frequency of the iodine-stabilized He-Ne laser; calculating the negative of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the multiple first temperature-induced frequency change rates; and calculating the negative of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the multiple second temperature-induced frequency change rates. A first temperature gradient between the measuring cavity and the copper cavity is determined based on the plurality of first temperature-induced frequency change rates, and a second temperature gradient between the reference cavity and the copper cavity is determined based on the plurality of second temperature-induced frequency change rates. The method of determining a first temperature gradient between the measurement cavity and the copper cavity based on the plurality of first temperature-induced frequency change rates, and determining a second temperature gradient between the reference cavity and the copper cavity based on the plurality of second temperature-induced frequency change rates, includes: receiving a measurement request, the measurement request including a first current temperature of the measurement cavity, a first current frequency change of the measurement cavity, a second current temperature of the reference cavity, and a second current frequency change of the reference cavity; determining a first target temperature-induced frequency change rate corresponding to the first current temperature, and determining a second target temperature-induced frequency change rate corresponding to the second current temperature; determining the ratio of the first current frequency change to the first target temperature-induced frequency change rate as the first temperature gradient, and determining the ratio of the second current frequency change to the second target temperature-induced frequency change rate as the second temperature gradient.

2. The method according to claim 1, characterized in that, Determine the sample data, including: A first initial temperature of the inner heating layer is determined, and a second initial temperature of the outer heating layer is determined. The inner heating layer and the outer heating layer are used to control the temperature environment of the FP resonant cavity. The copper cavity includes the inner heating layer and the outer heating layer. The pressure chamber is evacuated until the current vacuum level of the FP resonant cavity is greater than or equal to the vacuum level threshold. The first initial frequency of the measurement cavity and the second initial frequency of the reference cavity are obtained. The pressure chamber is used to control the pressure environment of the FP resonant cavity. A preset gas at a preset pressure is introduced into the pressure chamber. The temperatures of the inner heating layer and the outer heating layer are adjusted according to the target step temperature. After each temperature adjustment, the frequency is obtained to obtain multiple first real-time frequencies of the measuring cavity and multiple second real-time frequencies of the reference cavity. Based on the first initial frequency and the plurality of first real-time frequencies, the plurality of first frequency changes are determined, and based on the second initial frequency and the plurality of second real-time frequencies, the plurality of second frequency changes are determined. The sample data is determined to include the first initial temperature, the second initial temperature, the target step temperature, the plurality of first frequency changes, and the plurality of second frequency changes.

3. The method according to claim 2, characterized in that, The target step temperature includes a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature; adjusting the temperature of the inner heating layer and the outer heating layer according to the target step temperature includes: The inner heating layer is subjected to step heating treatment according to the first step temperature until the temperature of the inner heating layer reaches the first temperature threshold. The outer heating layer is subjected to step heating treatment according to the second step temperature until the temperature of the outer heating layer reaches the second temperature threshold. The inner heating layer is subjected to step cooling treatment according to the first step temperature until the temperature of the inner heating layer reaches the first initial temperature. The outer heating layer is subjected to step cooling treatment according to the second step temperature until the temperature of the outer heating layer reaches the second initial temperature. The inner heating layer is subjected to step heating treatment according to the third step temperature until the temperature of the inner heating layer reaches the first temperature threshold. The outer heating layer is subjected to step heating treatment according to the fourth step temperature until the temperature of the outer heating layer reaches the second temperature threshold. The inner heating layer is subjected to step cooling treatment according to the third step temperature until the temperature of the inner heating layer reaches the first initial temperature. The outer heating layer is subjected to step cooling treatment according to the fourth step temperature until the temperature of the outer heating layer reaches the second initial temperature.

4. The method according to claim 3, characterized in that, After each temperature adjustment, the frequency is acquired to obtain multiple first real-time frequencies of the measuring cavity and multiple second real-time frequencies of the reference cavity, including: The real-time temperature is determined using a standard thermometer in the pressure chamber after each temperature adjustment. If the fluctuation value of the real-time temperature within a preset time period is less than the fluctuation value threshold, then the first beat frequency between the measuring cavity and the reference cavity, and the second beat frequency between the reference cavity and the laser are obtained. The plurality of first real-time frequencies are determined based on the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser; the plurality of second real-time frequencies are determined based on the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser.

5. The method according to any one of claims 1-4, characterized in that, The sample data is fitted to obtain a first frequency change coefficient of the frequency change of the measurement cavity as a function of temperature, and a second frequency change coefficient of the frequency change of the reference cavity as a function of temperature, including: The first correction frequency and the second correction frequency are determined based on the gas pressure change introduced by the vacuum gas release effect, the FP cavity deformation coefficient, and the cavity mirror reflection phase shift correction coefficient. The plurality of first frequency changes are corrected by the first correction frequency to obtain a plurality of first target frequency changes, and the plurality of second frequency changes are corrected by the second correction frequency to obtain a plurality of second target frequency changes. The multiple target temperatures, the multiple first target frequency changes, and the multiple second target frequency changes are fitted to obtain the first frequency change coefficient and the second frequency change coefficient.

6. A temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, characterized in that, include: A determination module is used to determine sample data, which includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures. The sample data is obtained by stepping temperature adjustment and frequency measurement of a Fabry-Perot (FP) resonator. The FP resonator includes a measurement cavity and a reference cavity. The fitting module is used to perform fitting processing on the sample data to obtain a first frequency change coefficient of the frequency change of the measurement cavity as a function of temperature, and a second frequency change coefficient of the frequency change of the reference cavity as a function of temperature. A first calculation module is used to determine multiple first thermal expansion coefficients of the measuring cavity based on the first frequency change coefficient and the multiple target temperatures, and to determine multiple second thermal expansion coefficients of the reference cavity based on the second frequency change coefficient and the multiple target temperatures. The first coefficient of thermal expansion satisfies the following formula: in, This represents the first coefficient of thermal expansion at the target temperature. and This represents the first frequency variation coefficient at the target temperature. Indicates the initial temperature; The second calculation module is used to determine multiple first temperature-induced frequency change rates of the measuring cavity based on the multiple first thermal expansion coefficients, and to determine multiple second temperature-induced frequency change rates of the reference cavity based on the multiple second thermal expansion coefficients. The process of determining multiple first temperature-induced frequency change rates of the measurement cavity based on the multiple first thermal expansion coefficients and multiple second temperature-induced frequency change rates of the reference cavity based on the multiple second thermal expansion coefficients includes: determining the absolute frequency of the iodine-stabilized He-Ne laser; calculating the negative of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the multiple first temperature-induced frequency change rates; and calculating the negative of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser to obtain the multiple second temperature-induced frequency change rates. The processing module is used to determine a first temperature gradient between the measuring cavity and the copper cavity based on the plurality of first temperature-induced frequency change rates, and to determine a second temperature gradient between the reference cavity and the copper cavity based on the plurality of second temperature-induced frequency change rates. The method of determining a first temperature gradient between the measurement cavity and the copper cavity based on the plurality of first temperature-induced frequency change rates, and determining a second temperature gradient between the reference cavity and the copper cavity based on the plurality of second temperature-induced frequency change rates, includes: receiving a measurement request, the measurement request including a first current temperature of the measurement cavity, a first current frequency change of the measurement cavity, a second current temperature of the reference cavity, and a second current frequency change of the reference cavity; determining a first target temperature-induced frequency change rate corresponding to the first current temperature, and determining a second target temperature-induced frequency change rate corresponding to the second current temperature; determining the ratio of the first current frequency change to the first target temperature-induced frequency change rate as the first temperature gradient, and determining the ratio of the second current frequency change to the second target temperature-induced frequency change rate as the second temperature gradient.

7. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-5.

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