Method for measuring temperature gradient between optical pressure standard FP resonant cavity and temperature control copper cavity

Abstract

The invention provides a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature control copper cavity. Comprises: determining sample data; fitting the sample data to obtain a first frequency change coefficient of the frequency change quantity of the measurement cavity along with the temperature change and a second frequency change coefficient of the frequency change quantity of the reference cavity along with the temperature change; determining a plurality of first thermal expansion coefficients of the measurement cavity, and determining 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 determining a plurality of second temperature-induced frequency change rates of the reference cavity; a first temperature gradient between the measuring cavity and the copper cavity is determined, and a second temperature gradient between the reference cavity and the copper cavity is determined. According to the scheme, fitting processing and calculation are performed on the sample data to obtain the temperature gradient of the FP resonant cavity and the copper cavity, so that the actual temperature of the gas in the FP resonant cavity is corrected according to the temperature gradient, and the accuracy of substituting the gas temperature into the incidence relation to measure the pressure is improved.

Description

Technical Field

[0001] The present application relates to the technical field of optical pressure measurement, 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 Art

[0002] Pressure is one of the commonly used measurement parameters in industrial production and scientific research, and pressure testing is performed using a unified pressure standard. The optical pressure standard based on the Fabry-Perot (FP) resonant cavity combines the gas thermodynamics equation and the Lorentz-Lorenz equation to establish the correlation between gas pressure and its refractive index. By measuring the change in the laser resonance frequency of the FP resonant cavity under different gas pressures, the pressure of the gas filled in the FP resonant cavity is determined, and the pressure value is traced back to basic physical constants (such as the Boltzmann constant, etc.) and basic physical properties of the gas (such as electrical susceptibility or magnetic susceptibility, etc.). It has the advantage of high measurement accuracy and is the trend of ultra-precision development of 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. The temperature is substituted into the correlation between gas pressure and refractive index to obtain the pressure of the gas to be measured in the FP resonant cavity.

[0004] However, there is a temperature gradient between the FP resonant cavity and the copper cavity, which causes an error between the temperature controlled by the temperature control module and the actual temperature of the gas in the FP resonant cavity, which in turn leads to low accuracy in measuring the pressure by substituting the correlation relationship. Summary of the invention

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

[0006] In a first aspect, the present application provides a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, comprising: determining sample data, the sample data comprising a plurality of first frequency variation amounts and a plurality of second frequency variation amounts corresponding to a plurality of target temperatures, the sample data being obtained by performing step temperature adjustment on a Fabry-Perot FP resonant cavity and performing frequency measurement, the FP resonant cavity comprising a measuring cavity and a reference cavity; fitting the sample data to obtain a first frequency variation coefficient of the frequency variation amount of the measuring cavity as a function of temperature, and a second frequency variation coefficient of the frequency variation amount of the reference cavity as a function of temperature; and obtaining a frequency gradient between the first and second frequency variation amounts according to the first frequency variation amount. According to the multiple frequency change coefficients and the multiple target temperatures, multiple first thermal expansion coefficients of the measuring cavity are determined; according to the second frequency change coefficient and the multiple target temperatures, multiple second thermal expansion coefficients of the reference cavity are determined; according to the multiple first thermal expansion coefficients, multiple first temperature-induced frequency change rates of the measuring cavity are determined; according to the multiple second thermal expansion coefficients, multiple second temperature-induced frequency change rates of the reference cavity are determined; according to the multiple first temperature-induced frequency change rates, a first temperature gradient between the measuring cavity and the copper cavity is determined; according to the multiple first temperature-induced frequency change rates, a second temperature gradient between the reference cavity and the copper cavity is determined.

[0007] In a possible implementation, determining sample data includes: determining a first initial temperature of an inner heating layer, determining a second initial temperature of an outer heating layer, the inner heating layer and the outer heating layer being used to control the temperature environment of the FP resonant cavity, the copper cavity including the inner heating layer and the outer heating layer; evacuating a pressure chamber until a current vacuum degree of the FP resonant cavity is greater than or equal to a vacuum degree threshold, obtaining a first initial frequency of the measuring cavity, and a second initial frequency of the reference cavity, the pressure chamber being used to control the pressure environment of the FP resonant cavity; filling the pressure chamber with a preset gas of a preset pressure, adjusting the temperature of the inner heating layer and the outer heating layer according to a target step temperature, obtaining a frequency after each temperature adjustment to obtain a plurality of first real-time frequencies of the measuring cavity, and a plurality of second real-time frequencies of the reference cavity; determining a plurality of first frequency changes according to the first initial frequency and the plurality of first real-time frequencies, and determining a plurality of second frequency changes according to the second initial frequency and the plurality of second real-time frequencies; determining that the sample data includes 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.

[0008] In a possible implementation manner, the target step temperature includes a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature; adjusting the temperatures 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 the first initial temperature, performing step cooling treatment on the outer heating layer according to the second step temperature until the temperature of the inner heating layer reaches the first initial temperature, The outer heating layer is subjected to step-by-step cooling according to the temperature until the temperature of the outer heating layer reaches the second initial temperature; the inner heating layer is subjected to step-by-step heating according to the third step temperature until the temperature of the inner heating layer reaches the first temperature threshold, and the outer heating layer is subjected to step-by-step heating 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-by-step cooling according to the third step temperature until the temperature of the inner heating layer reaches the first initial temperature, and the outer heating layer is subjected to step-by-step cooling according to the fourth step temperature until the temperature of the outer heating layer reaches the second initial temperature.

[0009] In a possible implementation, the frequency is acquired after each temperature adjustment to obtain a plurality of first real-time frequencies of the measuring cavity and a plurality of second real-time frequencies of the reference cavity, including: determining the real-time temperature by a standard thermometer in a pressure chamber after each temperature adjustment; if the fluctuation value of the real-time temperature within a preset time length is less than a fluctuation value threshold, acquiring 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 plurality of first real-time frequencies according to the first beat frequency, the second beat frequency, and the absolute frequency of an iodine-stabilized He-Ne laser, and determining the plurality of second real-time beat frequencies according to the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser.

[0010] In a possible implementation, the sample data is fitted to obtain a first frequency variation coefficient of the frequency variation of the measuring cavity as a function of temperature, and a second frequency variation coefficient of the frequency variation of the reference cavity as a function of temperature, including: determining a first correction frequency and a second correction frequency according to a gas pressure variation introduced by a vacuum outgassing effect, an FP cavity deformation coefficient, and a cavity mirror reflection phase shift correction coefficient; correcting the multiple first frequency variations by the first correction frequency to obtain multiple first target frequency variations, and correcting the multiple second frequency transformations according to the second correction frequency to obtain multiple second target frequency variations; and fitting the multiple target temperatures, the multiple first target frequency variations, and the multiple second target frequency variations to obtain the first frequency variation coefficient and the second frequency variation coefficient.

[0011] In a possible implementation, a plurality of first temperature-induced frequency change rates of the measurement cavity are determined according to the plurality of first thermal expansion coefficients, and a plurality of second temperature-induced frequency change rates of the reference cavity are determined according to the plurality of second thermal expansion coefficients, including: determining the absolute frequency of an iodine-stabilized He-Ne laser; respectively 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 respectively 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 a possible implementation, the first temperature gradient between the measuring cavity and the copper cavity is determined according to the multiple first temperature-induced frequency change rates, and the second temperature gradient between the reference cavity and the copper cavity is determined according to the multiple second temperature-induced frequency change rates, including: receiving a measurement request, the measurement request including a first current temperature of the measuring cavity, a first current frequency change of the measuring 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 a ratio of the first current frequency change to the first target temperature-induced frequency change rate as the first temperature gradient, and determining a ratio of the second current frequency change to the second target temperature-induced frequency change rate as the second temperature gradient.

[0013] In a second aspect, the present application provides a temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, comprising: a determination module, used to determine sample data, wherein the sample data comprises a plurality of first frequency variation amounts and a plurality of second frequency variation amounts corresponding to a plurality of target temperatures, wherein the sample data is obtained by performing step temperature adjustment on a Fabry-Perot FP resonant cavity and performing frequency measurement, wherein the FP resonant cavity comprises a measuring cavity and a reference cavity; a fitting module, used to perform fitting processing on the sample data, and obtain a first frequency variation coefficient of the frequency variation amount of the measuring cavity as a function of temperature, and a second frequency variation coefficient of the frequency variation amount of the reference cavity as a function of temperature; a first calculation module, used to calculate the frequency variation amount of the measuring cavity according to the first frequency variation coefficient of the reference cavity according to the second ... first frequency variation coefficient of the reference cavity according to the second frequency variation coefficient of the reference cavity according to the second frequency variation coefficient of the reference cavity according to the first frequency variation coefficient of the reference cavity according to the second frequency variation coefficient of the reference cavity according to the first frequency variation coefficient of the reference cavity A frequency change coefficient and the multiple target temperatures are used to determine the multiple first thermal expansion coefficients of the measuring cavity, and the multiple second thermal expansion coefficients of the reference cavity are determined according to the second frequency change coefficient and the multiple target temperatures; a second calculation module is used to determine the multiple first temperature-induced frequency change rates of the measuring cavity according to the multiple first thermal expansion coefficients, and the multiple second temperature-induced frequency change rates of the reference cavity according to the multiple second thermal expansion coefficients; a processing module is used to determine the first temperature gradient between the measuring cavity and the copper cavity according to the multiple first temperature-induced frequency change rates, and determine the second temperature gradient between the reference cavity and the copper cavity according to the multiple second temperature-induced frequency change rates.

[0014] In a possible implementation manner, the determination module is specifically used to determine a first initial temperature of an inner heating layer and a second initial temperature of an outer heating layer, wherein the inner heating layer and the outer heating layer are used to control the temperature environment of the FP resonant cavity, and the copper cavity includes the inner heating layer and the outer heating layer; the determination module is specifically used to evacuate the pressure chamber until the current vacuum degree of the FP resonant cavity is greater than or equal to a vacuum degree threshold, obtain the first initial frequency of the measuring cavity, and the second initial frequency of the reference cavity, wherein the pressure chamber is used to control the pressure environment of the FP resonant cavity; the determination module is specifically used to fill the pressure chamber with a preset gas of a preset pressure. , adjusting the temperatures of the inner heating layer and the outer heating layer according to the target step temperature, acquiring the frequencies after each temperature adjustment to obtain multiple first real-time frequencies of the measuring cavity and multiple second real-time frequencies of the reference cavity; the determination module is specifically used to determine the multiple first frequency changes according to the first initial frequency and the multiple first real-time frequencies, and to determine the multiple second frequency changes according to the second initial frequency and the multiple second real-time frequencies; the determination module is specifically used 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 a possible implementation manner, the target step temperature includes a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature; the determination module is specifically used 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 to 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 determination module is specifically further used 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 to perform step-cooling treatment on the outer heating layer according to the second step temperature. 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 further 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 a possible implementation, the determination module is specifically used to determine the real-time temperature through a standard thermometer in the pressure chamber after each temperature adjustment; the determination module is also specifically used to obtain the first beat frequency between the measurement cavity and the reference cavity, and the second beat frequency between the reference cavity and the laser if the fluctuation value of the real-time temperature within a preset time length is less than the fluctuation value threshold; the determination module is also specifically used to determine the multiple first real-time frequencies according to the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser, and determine the multiple second real-time beat frequencies according to the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser.

[0017] In a possible embodiment, the system also includes: a correction module, which is used to determine the first correction frequency and the second correction frequency according to the gas pressure change introduced by the vacuum degassing effect, the FP cavity deformation coefficient, and the cavity mirror reflection phase shift correction coefficient; the correction module is also used to correct the multiple first frequency changes by the first correction frequency to obtain multiple first target frequency changes, and correct the multiple second frequency transformations according to the second correction frequency to obtain multiple second target frequency changes; the correction module is also used to fit the multiple target temperatures, the multiple first target frequency changes, and the multiple second target frequency changes to obtain the first frequency change coefficient and the second frequency change coefficient.

[0018] In a possible implementation, the system further includes: an execution module, used to determine the absolute frequency of the iodine-stabilized He-Ne laser; the execution module is also used to respectively calculate the negative number 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 respectively calculate the negative number 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.

[0019] In a possible embodiment, the system also includes: a measurement module, used to receive a measurement request, the measurement request including a first current temperature of the measurement chamber, a first current frequency change of the measurement chamber, a second current temperature of the reference chamber, and a second current frequency change of the reference chamber; the measurement module is also used to determine a frequency change rate caused by a first target temperature corresponding to the first current temperature, and determine a frequency change rate caused by a second target temperature corresponding to the second current temperature; the measurement module is also used to determine a ratio of the first current frequency change to the frequency change rate caused by the first target temperature as the first temperature gradient, and determine a ratio of the second current frequency change to the frequency change rate caused by the second target temperature as the second temperature gradient.

[0020] In a third aspect, the present application provides an electronic device comprising: 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 any method described in the first aspect.

[0021] In a fourth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are executed by a processor as described in any one of the methods in the first aspect.

[0022] In a fifth aspect, the present application provides a computer program product, comprising a computer program, wherein the computer program is executed by a processor as in any one of the methods in the first aspect.

[0023] The present application provides a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, the method comprising: determining sample data, the sample data comprising a plurality of first frequency variation amounts and a plurality of second frequency variation amounts corresponding to a plurality of target temperatures, the sample data being obtained by performing step temperature adjustment on a Fabry-Perot FP resonant cavity and performing frequency measurement, the FP resonant cavity comprising a measuring cavity and a reference cavity; fitting the sample data to obtain a first frequency variation coefficient of the frequency variation amount of the measuring cavity as a function of temperature, and a second frequency variation coefficient of the frequency variation amount of the reference cavity as a function of temperature; and fitting the sample data according to the first frequency variation coefficient. The first thermal expansion coefficients of the measuring cavity are determined according to the second frequency change coefficient and the target temperatures; the second thermal expansion coefficients of the reference cavity are determined according to the first thermal expansion coefficients; the first temperature-induced frequency change rates of the measuring cavity are determined according to the second thermal expansion coefficients; the second temperature-induced frequency change rates of the reference cavity are determined according to the second thermal expansion coefficients; the first temperature gradient between the measuring cavity and the copper cavity is determined according to the first temperature-induced frequency change rates; the second temperature gradient between the reference cavity and the copper cavity is determined according to the second temperature-induced frequency change rates. In the above scheme, the temperature gradient between the FP resonant cavity and the copper cavity is obtained by fitting and calculating the sample data, so that the actual temperature of the gas in the FP resonant cavity is corrected according to the temperature gradient, thereby improving the accuracy of measuring the pressure by substituting the temperature into the correlation relationship. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0026] Figure 2 A schematic flow chart of a method for measuring a temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in an embodiment of the present application;

[0027] Figure 3 A schematic flow chart of a method for measuring a temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in an embodiment of the present application;

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

[0029] Figure 5 A schematic diagram of determining the thermal expansion coefficient provided in an embodiment of the present application;

[0030] Figure 6 A schematic diagram of determining the rate of change of frequency caused by temperature provided in an embodiment of the present application;

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

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

[0033] Fig. 9 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0034] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of systems and methods consistent with some aspects of the present 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, and the collection, use, processing, transmission, provision, disclosure and application of the relevant data comply with the relevant laws, regulations and standards of the relevant countries and regions, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances 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 the present 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 the present application is not limited.

[0038] Figure 1 A schematic diagram of an application scenario of a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in an embodiment of the present application is given in combination with the illustrated scenario as an example: the optical pressure standard includes a temperature control system, an optical path system, and a dual FP cavity, wherein the temperature control system includes 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 feedback-controlled by a temperature controller. The pressure chamber is used for pressure control and is placed in the middle of the temperature control system. The gas to be measured is passed 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. The laser source emits laser light through the FP resonant cavity to reach the detector. The frequency change identified by the detector and the measured temperature of the standard platinum resistance thermometer are substituted into the correlation relationship to obtain the pressure of the gas to be measured. Among them, CDG is a thin film capacitive pressure gauge, and the value displayed by CDG is used to characterize the change in gas pressure introduced by the vacuum outgassing effect.

[0039] In practical applications, the FP resonant cavity is measured under background vacuum conditions. Under background vacuum conditions, heat conduction is weak, and the thermal link between the FP resonant cavity and the copper cavity is disconnected, 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 pressure measurement accuracy.

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

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

[0042] Figure 2 A schematic flow chart of a method for measuring a temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in an embodiment of the present application, the method comprising the following steps:

[0043] S201 . Determine sample data, where the sample data includes a plurality of first frequency changes and a plurality of second frequency changes corresponding to a plurality of target temperatures.

[0044] The sample data is obtained by performing step temperature adjustment on a Fabry-Perot FP resonant cavity and performing frequency measurement. The FP resonant cavity includes a measurement cavity and a reference cavity.

[0045] Exemplarily, the measuring cavity is a cavity into which the pressure of the gas to be measured is introduced, and the reference cavity is a cavity that provides a frequency reference. The first frequency variation corresponds to the measuring cavity, and the second frequency variation corresponds to the reference cavity.

[0046] Combined with the scenario example, the frequency of the measurement cavity and the reference cavity is measured respectively. The frequency at the initial temperature and the frequency at each target temperature are measured, and the frequency change is determined according to the change value of the frequency at each target temperature compared with the frequency at the initial temperature.

[0047] S202, performing fitting processing on the sample data to obtain a first frequency variation coefficient of the frequency variation of the measurement cavity as it varies with temperature, and a second frequency variation coefficient of the frequency variation of the reference cavity as it varies with temperature.

[0048] Exemplarily, a suitable function model is determined according to the relationship between the frequency change and the temperature, and then fitting is performed according to a statistical method such as the least squares method to obtain parameters in the function model, namely, the first frequency change coefficient and the second frequency change coefficient.

[0049] Optionally, the sample data is divided into a test set and a validation set, the test set is fitted to obtain a function, and the function is validated using the validation set.

[0050] S203, determining a plurality of first thermal expansion coefficients of the measurement cavity according to the first frequency variation coefficient and a plurality of target temperatures, and determining a plurality of second thermal expansion coefficients of the reference cavity according to the second frequency variation coefficient and a plurality of target temperatures.

[0051] The coefficient of thermal expansion (CTE) of the FP cavity indicates the rate of change of the size of the FP cavity when the temperature changes. For the FP cavity, the CTE will affect the length of the cavity, which in turn affects the optical standing wave mode in the cavity, and ultimately affects the resonant frequency of the FP cavity.

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

[0053] S204, determining a plurality of first temperature-induced frequency change rates of the measurement cavity according to the plurality of first thermal expansion coefficients, and determining a plurality of second temperature-induced frequency change rates of the reference cavity according to the plurality of second thermal expansion coefficients.

[0054] The temperature-induced frequency change rate indicates how the frequency of the FP resonant cavity changes with temperature.

[0055] For example, there is a direct relationship between the thermal expansion coefficient and the temperature-induced frequency change rate. The thermal expansion coefficient 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 the light. When the temperature changes, the length of the FP resonant cavity will change, which in turn will cause the resonant frequency of the light in the cavity to change. Therefore, the temperature-induced frequency change rate can be regarded as a comprehensive reflection of the relationship between the thermal expansion coefficient and the length and frequency of the FP resonant cavity.

[0056] S205, determining a first temperature gradient between the measurement cavity and the copper cavity according to a plurality of first temperature-induced frequency change rates, and determining a second temperature gradient between the reference cavity and the copper cavity according to a plurality of second temperature-induced frequency change rates.

[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. The actual temperature of the gas in the measuring cavity and the actual temperature of the gas in the reference cavity can be determined by the first temperature gradient, the second temperature gradient, and the temperature of the copper cavity.

[0058] Combined with the scenario example, the present application measures the temperature gradient between the FP resonant cavity and the temperature-controlled copper cavity before the optical pressure standard performs pressure measurement, and obtains a more accurate temperature of the gas in the FP resonant cavity through temperature gradient correction when performing pressure measurement, thereby improving the accuracy of pressure measurement.

[0059] The embodiment of the present application provides a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity, comprising: determining sample data, the sample data comprising a plurality of first frequency variation amounts and a plurality of second frequency variation amounts corresponding to a plurality of target temperatures, the sample data being obtained by performing step temperature adjustment on a Fabry-Perot FP resonant cavity and performing frequency measurement, the FP resonant cavity comprising a measuring cavity and a reference cavity; performing fitting processing on the sample data to obtain a first frequency variation coefficient of the frequency variation amount of the measuring cavity as a function of temperature, and a second frequency variation coefficient of the frequency variation amount of the reference cavity as a function of temperature; determining a plurality of first thermal expansion coefficients of the measuring cavity according to the first frequency variation coefficient and a plurality of target temperatures, and determining a plurality of second thermal expansion coefficients of the reference cavity according to the second frequency variation coefficient and a plurality of target temperatures; determining a plurality of first temperature-induced frequency variation rates of the measuring cavity according to the plurality of first thermal expansion coefficients, and determining a plurality of second temperature-induced frequency variation rates of the reference cavity according to the plurality of second thermal expansion coefficients; determining a first temperature gradient between the measuring cavity and the copper cavity according to the plurality of first temperature-induced frequency variation rates, and determining a second temperature gradient between the reference cavity and the copper cavity according to the plurality of second temperature-induced frequency variation rates. The above scheme obtains the temperature gradient of the FP resonant cavity and the copper cavity by fitting and calculating the sample data, and then corrects the actual temperature of the gas in the FP resonant cavity according to the temperature gradient, thereby improving the accuracy of measuring the pressure by substituting the gas temperature into the correlation relationship.

[0060] Based on any of the above embodiments, 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 described.

[0061] Figure 3 A schematic diagram of a method for measuring the temperature gradient between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in an embodiment of the present application. Figure 3 As shown, the method includes:

[0062] S301, determining a first initial temperature of an inner heating layer, and determining a second initial temperature of an 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, and the copper cavity includes the inner heating layer and the outer heating layer.

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

[0065] S302, evacuate the pressure chamber until the current vacuum degree of the FP resonant cavity is greater than or equal to the vacuum degree 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] Exemplarily, the pressure chamber is 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 pumped out of the pressure chamber to achieve a specified pressure environment.

[0068] Combined with the scenario example, the vacuum threshold is 10 -4 When the current vacuum degree of the FP resonant cavity reaches 10 -4 Stop vacuuming.

[0069] S303, filling the pressure chamber with a preset gas of a preset pressure, adjusting the temperatures of the inner heating layer and the outer heating layer according to the target step temperature, and obtaining the frequency after each temperature adjustment to obtain multiple first real-time frequencies of the measurement cavity and multiple second real-time frequencies of the reference cavity.

[0070] Combined with the scenario example, after the vacuum reaches the vacuum threshold, the vacuum valve is closed to stop the vacuum. 100Pa of high-purity nitrogen is filled into the pressure chamber.

[0071] For example, the thermal conductivity of gas is related to pressure and temperature. The thermal conductivity increases with the increase of pressure. When the pressure is lower than 100Pa, the thermal conductivity increases linearly with the pressure. When the pressure is higher than 100Pa, the thermal conductivity increases by 1% for every 100kPa pressure. Therefore, when the gas pressure is higher than 100Pa, the change of the thermal conductivity of gas caused by the pressure change can be ignored. Therefore, the measurement of the optical pressure standard thermal expansion coefficient under the gas pressure of 100Pa can avoid the temperature gradient between the FP resonant cavity and the temperature-controlled copper cavity under the background vacuum, and reduce the time consumption of the vacuum pumping process.

[0072] A feasible implementation method, the target step temperature includes a first step temperature, a second step temperature, a third step temperature, and a fourth step temperature; the temperatures of the inner heating layer and the outer heating layer can be adjusted by the following method: 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 a first temperature threshold, and 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 a 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 a first initial temperature, and 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 a 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 a first temperature threshold, and 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 a 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 a first initial temperature, and 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 a 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] Combined with the scenario example, by adjusting the temperature step by step through the first and second step temperatures, sample data with wider intervals can be obtained, and by adjusting the temperature step by step through the third and fourth step temperatures, sample data with narrower intervals can be obtained. The accuracy of the association can be improved by determining the initial fitting through the sample data with wider intervals and then optimizing through the sample data with narrower intervals.

[0075] Next, combine Figure 4 The step temperature adjustment of the inner heating layer is described.

[0076] Figure 4 Schematic diagram of the step temperature adjustment of the inner heating layer provided in the embodiment of the present 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: step-by-step temperature increase from the initial temperature to the temperature threshold according to the first step temperature, temperature reduction from the temperature threshold to the initial temperature according to the first step temperature, step-by-step temperature increase from the initial temperature to the temperature threshold according to the third step temperature, and temperature reduction 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 of the outer heating layer is similar to the step temperature adjustment method of the inner heating layer.

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

[0079] A feasible implementation method can obtain the first real-time frequency and the second real-time frequency by the following method: 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 length is less than the fluctuation value threshold, the first beat frequency between the measurement cavity and the reference cavity, and the second beat frequency between the reference cavity and the laser are obtained; according to 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 according to the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser, multiple second real-time beat frequencies are determined.

[0080] 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] Combined with the scenario example, for example, after each temperature adjustment, obtain the real-time temperature of the standard thermometer. If the real-time temperature fluctuation value within 5s is less than 1mK, it means that the FP resonant cavity has reached thermal equilibrium. Testing and obtaining the beat frequency can improve the accuracy of the beat frequency.

[0083] Exemplarily, 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 through a laser and a photodetector, and the real-time frequency can be indirectly measured through the beat frequency, thereby increasing the measurement frequency range.

[0085] S304: Determine a plurality of first frequency change amounts according to the first initial frequency and the plurality of first real-time frequencies, and determine a plurality of second frequency change amounts according to the second initial frequency and the plurality of second real-time frequencies.

[0086] Combined with the scenario example, the first initial frequency is The first real-time frequency is The first frequency variation The second initial frequency is The second real-time frequency is The second frequency variation

[0087] Exemplarily, 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 including multiple target temperatures, multiple first frequency changes, and multiple second frequency changes.

[0088] S305 , determining that the sample data includes a first initial temperature, a second initial temperature, a target step temperature, a plurality of first frequency changes, and a plurality of second frequency changes.

[0089] Exemplarily, on the basis of the first initial temperature and the second initial temperature, by sequentially increasing the target step temperature, temperatures of multiple measurement frequencies are obtained, and the target temperature includes this temperature.

[0090] Optionally, the step temperature is determined according to the requirement of fitting accuracy.

[0091] Combined with the scenario example, within a certain range, the smaller the step temperature, the denser the sample data, and the more accurate the fitted parameters. Beyond a certain range, the smaller the step temperature, the more likely it is to overfit. Determine the corresponding relationship between the step temperature and the fitting accuracy, and determine the appropriate step temperature based on the requirements of the fitting accuracy and the corresponding relationship.

[0092] S306 , determining a first correction frequency and a second correction frequency according to the gas pressure variation introduced by the vacuum outgassing 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] Combined with the scenario example, the gas molecules adsorbed on the surface of the vacuum cavity and the seal will be released outward under non-evacuation conditions, resulting in reduced purity of the filled gas and drift in the pressure measurement. In the process of determining the thermal expansion coefficient of the optical pressure standard, the influence of the vacuum outgassing effect on the pressure measurement cannot be completely ignored. In addition, during the filling and degassing process of the FP resonant cavity, the high reflective mirror deforms slightly, resulting in measurement frequency drift, especially for the reference cavity that is in the background vacuum inside and gas pressure outside. Therefore, the accuracy of gas pressure measurement can be improved through frequency correction.

[0095] Exemplarily, the calculation formula of the first correction frequency is shown in formula (1), and the calculation formula of the second correction frequency is shown in formula (2):

[0096]

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

[0098] Among them, Δp represents the change in gas pressure, R is the gas constant, and υ p Indicates the filling gas pressure, d r is the deformation coefficient of the reference cavity, T is the thermodynamic temperature of the gas, d m is the deformation coefficient of the measuring cavity, ε α A represents the cavity mirror reflection phase shift correction coefficient, mix It is the effective molar polarizability of impurity gas produced by vacuum outgassing effect.

[0099] S307, correcting the plurality of first frequency changes by the first correction frequency to obtain a plurality of first target frequency changes, and correcting the plurality of second frequency changes by the second correction frequency to obtain a plurality of second target frequency changes.

[0100] In combination with the scenario example, for each first frequency change, the first correction frequency is subtracted to obtain the corresponding first target frequency change, and for each second frequency change, the second correction frequency is subtracted to obtain the corresponding second target frequency change.

[0101] S308 , performing fitting processing on the multiple target temperatures, the multiple first target frequency changes, and the multiple second target frequency changes to obtain a first frequency change coefficient and a second frequency change coefficient.

[0102] Exemplarily, the fitting process is performed based on formula (3) and formula (4):

[0103]

[0104] Among them, Δυ MC is the first frequency variation, υ is the absolute frequency of the iodine-stabilized He-Ne laser, a 0 、a 1 、a 2 is the first frequency variation coefficient, a 3 、a 4 、a 5 is the second frequency variation coefficient, T 90 is the target temperature, Ti 0 is the initial temperature.

[0105] Combined with the scenario example, the first target frequency change amount and the second target frequency change amount obtained by correction can effectively reduce the error, thereby improving the accuracy of the first frequency change coefficient and the second frequency change coefficient.

[0106] S309, determining a plurality of first thermal expansion coefficients of the measurement cavity according to the first frequency variation coefficient and a plurality of target temperatures, and determining a plurality of second thermal expansion coefficients of the reference cavity according to the second frequency variation coefficient and a plurality of target temperatures.

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

[0108] Exemplarily, the first thermal expansion coefficient of the measurement cavity is calculated by formula (5):

[0109] α(T 90 )=a 1 +a 2 (T 90 -Ti 0 )····················(5)

[0110] Among them, α(T 90 ) indicates T 90 The first thermal expansion coefficient at temperature. a 0 、a 1 It is obtained by fitting formula (3).

[0111] It should be noted that the calculation method of the second thermal expansion coefficient is similar and will not be repeated in this application.

[0112] Next, combine Figure 5 Determination of the thermal expansion coefficient will be described.

[0113] Figure 5 This is a schematic diagram of determining the thermal expansion coefficient provided in the embodiment of the present application. Figure 5 As shown, the sample data is fitted to obtain the frequency variation coefficient, and a first corresponding relationship, namely, formula (5), is established based on the frequency variation coefficient. Any current temperature is substituted into the first corresponding relationship to obtain the thermal expansion coefficient corresponding to the current temperature.

[0114] S310. Determine a plurality of first temperature-induced frequency change rates of the measurement cavity according to a plurality of first thermal expansion coefficients, and determine a plurality of second temperature-induced frequency change rates of the reference cavity according to a plurality of second thermal expansion coefficients.

[0115] A feasible implementation method can determine the first temperature-induced frequency change rate and the second temperature-induced frequency change rate by the following method: determine the absolute frequency of the iodine-stabilized He-Ne laser; calculate the negative number of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser respectively to obtain multiple first temperature-induced frequency change rates, and calculate the negative number of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser respectively to obtain multiple second temperature-induced frequency change rates.

[0116] Exemplarily, the first temperature-induced frequency change rate of the measurement cavity is calculated by formula (6):

[0117]

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

[0119] Combined with the scenario example, the temperature-induced frequency change rate represents the speed at which the frequency changes due to temperature changes. The temperature-induced frequency change rate is used to establish a corresponding relationship between the temperature and the speed at which the frequency changes.

[0120] It should be noted that the calculation method of the second temperature-induced frequency change rate is similar and will not be repeated in this application.

[0121] Next, combine Figure 6 Determination of the rate of change of frequency due to temperature is described.

[0122] Figure 6 This is a schematic diagram of determining the thermal expansion coefficient provided in the embodiment of the present application. Figure 6 As shown, any current temperature is substituted into the first corresponding relationship to obtain the thermal expansion coefficient corresponding to the current temperature, and the thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser are substituted into the second corresponding relationship, that is, formula (6) to calculate the temperature-induced frequency change rate corresponding to the current temperature.

[0123] S311, determining a first temperature gradient between the measurement cavity and the copper cavity according to a plurality of first temperature-induced frequency change rates, and determining a second temperature gradient between the reference cavity and the copper cavity according to a plurality of second temperature-induced frequency change rates.

[0124] Combined with the scenario example, multiple temperature-induced frequency change rates cover multiple operating parameters. In actual applications, the corresponding temperature-induced frequency change rate is determined according to the actual operating parameters, and the corresponding temperature gradient is determined on this basis.

[0125] A feasible implementation method can determine the temperature gradient by the following method: receiving a measurement request, the measurement request including the first current temperature of the measurement chamber, the first current frequency change of the measurement chamber, the second current temperature of the reference chamber, and the second current frequency change of the reference chamber; determining the frequency change rate caused by a first target temperature corresponding to the first current temperature, and determining the frequency change rate caused by a second target temperature corresponding to the second current temperature; determining the ratio of the first current frequency change to the frequency change rate caused by the first target temperature as the first temperature gradient, and determining the ratio of the second current frequency change to the frequency change rate caused by the second target temperature as the second temperature gradient.

[0126] The first current temperature and the second current temperature are measured by a standard thermometer.

[0127] Combined with the scenario example, taking the measurement cavity as an example, according to the first current temperature and formula (5), the first thermal expansion coefficient corresponding to the first current temperature is determined. According to 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 amount 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 of the first temperature gradient is similar and will not be repeated here.

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

[0130] Figure 7 This is a schematic diagram of the structure of a temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in an embodiment of the present 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, where the sample data includes multiple first frequency changes and multiple second frequency changes corresponding to multiple target temperatures. The sample data is obtained by performing step temperature adjustment on the Fabry-Perot FP resonant cavity and performing frequency measurement. The FP resonant cavity 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 a first frequency variation coefficient of the frequency variation of the measurement cavity with temperature variation and a second frequency variation coefficient of the frequency variation of the reference cavity with temperature variation.

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

[0134] The second calculation module 74 is used to determine a plurality of first temperature-induced frequency change rates of the measurement cavity according to the plurality of first thermal expansion coefficients, and to determine a plurality of second temperature-induced frequency change rates of the reference cavity according to the plurality of second thermal expansion coefficients.

[0135] The processing module 75 is used to determine the first temperature gradient between the measurement cavity and the copper cavity according to the multiple first temperature-induced frequency change rates, and to determine the second temperature gradient between the reference cavity and the copper cavity according to the multiple second temperature-induced frequency change rates.

[0136] Optionally, the determination module 71 may execute Figure 2 S201 in the embodiment.

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

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

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

[0140] Optionally, the processing module 75 may 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 embodiment of the present application can implement the technical solution shown in the above method embodiment, and its implementation principle and beneficial effects are similar, which will not be repeated here.

[0142] In a possible implementation manner, the determination module 71 is specifically configured to:

[0143] Determine a first initial temperature of the inner heating layer, and determine 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, and the copper cavity includes the inner heating layer and the outer heating layer;

[0144] The pressure chamber is evacuated until the current vacuum degree of the FP resonant cavity is greater than or equal to the vacuum degree threshold, and the first initial frequency of the measuring 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] Filling the pressure chamber with a preset gas of a preset pressure, adjusting the temperature of the inner heating layer and the outer heating layer according to the target step temperature, and acquiring the frequency after each temperature adjustment to obtain a plurality of first real-time frequencies of the measuring cavity and a plurality of second real-time frequencies of the reference cavity;

[0146] Determine a plurality of first frequency variation amounts according to the first initial frequency and the plurality of first real-time frequencies, and determine a plurality of second frequency variation amounts according to the second initial frequency and the plurality of second real-time frequencies;

[0147] The sample data is determined to include a first initial temperature, a second initial temperature, a target step temperature, a plurality of first frequency changes, and a plurality of second frequency changes.

[0148] In a 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 determination module 71 is specifically used to:

[0149] The inner heating layer is subjected to step-by-step heating according to the first step temperature until the temperature of the inner heating layer reaches a first temperature threshold, and the outer heating layer is subjected to step-by-step heating according to the second step temperature until the temperature of the outer heating layer reaches a second temperature threshold;

[0150] The inner heating layer is subjected to a step-by-step cooling process according to the first step temperature until the temperature of the inner heating layer reaches the first initial temperature, and the outer heating layer is subjected to a step-by-step cooling process according to the second step temperature until the temperature of the outer heating layer reaches the second initial temperature;

[0151] Performing step-heating treatment 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 performing step-heating treatment on the outer heating layer 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-by-step cooling according to the third step temperature until the temperature of the inner heating layer reaches the first initial temperature, and the outer heating layer is subjected to step-by-step cooling according to the fourth step temperature until the temperature of the outer heating layer reaches the second initial temperature.

[0153] In a possible implementation manner, the determination module 71 is specifically configured to:

[0154] After each temperature adjustment, the real-time temperature is determined by a standard thermometer in the pressure chamber;

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

[0156] A plurality of first real-time frequencies are determined according to the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser, and a plurality of second real-time beat frequencies are determined according to the second beat frequency and the absolute frequency of the iodine-stabilized He-Ne laser.

[0157] Figure 8 This is a schematic diagram of the structure of a temperature gradient measurement system between an optical pressure standard FP resonant cavity and a temperature-controlled copper cavity provided in an embodiment of the present application. Figure 7 Based on the embodiment shown, Figure 8As 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] The correction module 76 is used to:

[0159] Determine a first correction frequency and a second correction frequency according to a gas pressure change introduced by a vacuum outgassing effect, a FP cavity deformation coefficient, and a cavity mirror reflection phase shift correction coefficient;

[0160] Correcting a plurality of first frequency changes by a first correction frequency to obtain a plurality of first target frequency changes, and correcting a plurality of second frequency changes by a second correction frequency to obtain a plurality of second target frequency changes;

[0161] A fitting process is performed on a plurality of target temperatures, a plurality of first target frequency changes, and a plurality of second target frequency changes to obtain a first frequency change coefficient and a second frequency change coefficient.

[0162] The execution module 77 is used to:

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

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

[0165] The measuring module 78 is used to:

[0166] 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;

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

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

[0169] Fig. 9 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application is shown in FIG. Fig. 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, the memory 292, and the communication interface 293 may communicate with each other through the bus 294. The communication interface 293 may be used for information transmission. The processor 291 may call the logic instructions in the memory 292 to execute the method of the above embodiment.

[0171] In addition, the logic instructions in the above-mentioned memory 292 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product.

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

[0173] The memory 292 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required for at least one function; the data storage area may store data created according to the use of the terminal device, etc. In addition, the memory 292 may include a high-speed random access memory and may also include a non-volatile memory.

[0174] An embodiment of the present application provides a non-temporary computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method as described in the above embodiment.

[0175] An embodiment of the present application provides a computer program product, including a computer program, which implements the method of the above embodiment when the computer program is executed by a processor.

[0176] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present application.

[0177] It should be further noted that, although the various steps in the flowchart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowchart may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

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

[0179] In addition, unless otherwise specified, each functional unit / module in each embodiment of the present application may be integrated into one unit / module, each unit / module may exist physically separately, or two or more units / modules may be integrated together. The above-mentioned integrated unit / module may be implemented in the form of hardware or in the form of a software program module.

[0180] If the integrated unit / module is implemented in the form of hardware, the hardware may be a digital circuit, an analog circuit, etc. The physical implementation of the hardware structure includes but is not limited to transistors, memristors, etc. The processor may be any appropriate hardware processor, such as a CPU, a GPU, an FPGA, a DSP, and an ASIC, etc. The storage unit may be any appropriate magnetic storage medium or magneto-optical storage medium, such as a resistive random access memory RRAM (Resistive Random Access Memory), a dynamic random access memory DRAM (Dynamic Random Access Memory), a static random access memory SRAM (Static Random-Access Memory), an enhanced dynamic random access memory EDRAM (Enhanced Dynamic Random Access Memory), a high-bandwidth memory HBM (High-Bandwidth Memory), a hybrid memory cube HMC (Hybrid Memory Cube), etc.

[0181] If the integrated unit / module is implemented in the form of a software program module and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, 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, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0182] In the above embodiments, the description of each embodiment has its own emphasis. For the part not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0183] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0184] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present 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, the sample data including a plurality of first frequency variation amounts and a plurality of second frequency variation amounts corresponding to a plurality of target temperatures, the sample data being obtained by performing step temperature adjustment on a Fabry-Perot FP resonant cavity and performing frequency measurement, the FP resonant cavity including a measurement cavity and a reference cavity; Performing fitting processing on the sample data to obtain a first frequency variation coefficient of the frequency variation of the measuring cavity as the temperature changes, and a second frequency variation coefficient of the frequency variation of the reference cavity as the temperature changes; Determine a plurality of first thermal expansion coefficients of the measurement cavity according to the first frequency variation coefficient and the plurality of target temperatures, and determine a plurality of second thermal expansion coefficients of the reference cavity according to the second frequency variation coefficient and the plurality of target temperatures; Determine a plurality of first temperature-induced frequency change rates of the measurement cavity according to the plurality of first thermal expansion coefficients, and determine a plurality of second temperature-induced frequency change rates of the reference cavity according to the plurality of second thermal expansion coefficients; A first temperature gradient between the measurement cavity and the copper cavity is determined according to the plurality of first temperature-induced frequency change rates, and a second temperature gradient between the reference cavity and the copper cavity is determined according to the plurality of second temperature-induced frequency change rates.

2. The method according to claim 1, characterized in that Determine sample data, including: Determining a first initial temperature of an inner heating layer and determining a second initial temperature of an outer heating layer, wherein the inner heating layer and the outer heating layer are used to control the temperature environment of the FP resonant cavity, and the copper cavity includes the inner heating layer and the outer heating layer; The pressure chamber is evacuated until the current vacuum degree of the FP resonant cavity is greater than or equal to the vacuum degree threshold, and the first initial frequency of the measuring cavity and the second initial frequency of the reference cavity are obtained, wherein the pressure chamber is used to control the pressure environment of the FP resonant cavity; Filling the pressure chamber with a preset gas of a preset pressure, adjusting the temperature of the inner heating layer and the outer heating layer according to the target step temperature, and acquiring the frequency after each temperature adjustment to obtain a plurality of first real-time frequencies of the measuring cavity and a plurality of second real-time frequencies of the reference cavity; Determine the multiple first frequency change amounts according to the first initial frequency and the multiple first real-time frequencies, and determine the multiple second frequency change amounts according to the second initial frequency and the multiple second real-time frequencies; 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; and adjusting the temperature of the inner heating layer and the outer heating layer according to the target step temperature includes: Performing step-by-step heating 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 performing step-by-step heating 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 inner heating layer is subjected to a step-by-step cooling process according to the first step temperature until the temperature of the inner heating layer reaches the first initial temperature, and the outer heating layer is subjected to a step-by-step cooling process according to the second step temperature until the temperature of the outer heating layer reaches the second initial temperature; Performing step-heating treatment 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 performing step-heating treatment 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 inner heating layer is subjected to step-by-step cooling according to the third step temperature until the temperature of the inner heating layer reaches the first initial temperature, and the outer heating layer is subjected to step-by-step cooling 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 Acquiring the frequency after each temperature adjustment to obtain a plurality of first real-time frequencies of the measuring cavity and a plurality of second real-time frequencies of the reference cavity comprises: 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, a first beat frequency between the measurement cavity and the reference cavity, and a second beat frequency between the reference cavity and the laser are obtained; The multiple first real-time frequencies are determined according to the first beat frequency, the second beat frequency, and the absolute frequency of the iodine-stabilized He-Ne laser, and the multiple second real-time beat frequencies are determined according to 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 to 4, characterized in that The sample data is fitted to obtain a first frequency variation coefficient of the frequency variation of the measuring cavity with temperature variation and a second frequency variation coefficient of the frequency variation of the reference cavity with temperature variation, including: Determine a first correction frequency and a second correction frequency according to a gas pressure change introduced by a vacuum outgassing effect, a FP cavity deformation coefficient, and a cavity mirror reflection phase shift correction coefficient; Correcting the plurality of first frequency changes by the first correction frequency to obtain a plurality of first target frequency changes, and correcting the plurality of second frequency changes by the second correction frequency to obtain a plurality of second target frequency changes; The plurality of target temperatures, the plurality of first target frequency changes, and the plurality of second target frequency changes are fitted to obtain the first frequency change coefficient and the second frequency change coefficient.

6. The method according to claim 1, characterized in that Determining a plurality of first temperature-induced frequency change rates of the measurement cavity according to the plurality of first thermal expansion coefficients, and determining a plurality of second temperature-induced frequency change rates of the reference cavity according to the plurality of second thermal expansion coefficients, comprising: Determine the absolute frequency of an iodine-stabilized He-Ne laser; The negative number of the product of each first thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser is calculated respectively to obtain the multiple first temperature-induced frequency change rates, and the negative number of the product of each second thermal expansion coefficient and the absolute frequency of the iodine-stabilized He-Ne laser is calculated respectively to obtain the multiple second temperature-induced frequency change rates.

7. The method according to claim 1, characterized in that Determining a first temperature gradient between the measuring cavity and the copper cavity according to the plurality of first temperature-induced frequency change rates, and determining a second temperature gradient between the reference cavity and the copper cavity according to the plurality of second temperature-induced frequency change rates, comprising: 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; Determine a frequency change rate caused by a first target temperature corresponding to the first current temperature, and determine a frequency change rate caused by a second target temperature corresponding to the second current temperature; The ratio of the first current frequency change amount 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 amount to the second target temperature-induced frequency change rate is determined as the second temperature gradient.

8. 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, configured to determine sample data, wherein the sample data includes a plurality of first frequency variation amounts and a plurality of second frequency variation amounts corresponding to a plurality of target temperatures, wherein the sample data is obtained by performing step temperature adjustment on a Fabry-Perot FP resonant cavity and performing frequency measurement, wherein the FP resonant cavity includes a measurement cavity and a reference cavity; A fitting module, used for performing fitting processing on the sample data to obtain a first frequency variation coefficient of the frequency variation of the measuring cavity as the temperature changes, and a second frequency variation coefficient of the frequency variation of the reference cavity as the temperature changes; a first calculation module, configured to determine a plurality of first thermal expansion coefficients of the measurement cavity according to the first frequency variation coefficient and the plurality of target temperatures, and to determine a plurality of second thermal expansion coefficients of the reference cavity according to the second frequency variation coefficient and the plurality of target temperatures; a second calculation module, configured to determine a plurality of first temperature-induced frequency change rates of the measurement cavity according to the plurality of first thermal expansion coefficients, and to determine a plurality of second temperature-induced frequency change rates of the reference cavity according to the plurality of second thermal expansion coefficients; The processing module is used to determine the first temperature gradient between the measurement cavity and the copper cavity according to the multiple first temperature-induced frequency change rates, and to determine the second temperature gradient between the reference cavity and the copper cavity according to the multiple second temperature-induced frequency change rates.

9. An electronic device, characterized in that: include: 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 according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 7 when executed by a processor.

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