Gas reference temperature measurement method and device based on in-situ pressure measurement

Abstract

The present application relates to the technical field of temperature measurement, and discloses a gas reference temperature measurement method and device based on in-situ pressure measurement. The temperature measurement method comprises the following steps: obtaining a first density signal of a working gas under a known reference pressure when the temperature of a measurement chamber is at a known reference temperature; obtaining a second density signal of the working gas under a to-be-measured pressure while keeping the reference temperature unchanged; obtaining a third density signal of the working gas when the measurement chamber is at the to-be-measured pressure and a to-be-measured temperature; and determining the to-be-measured temperature based on the first density signal, the second density signal and the third density signal, and the reference temperature and the reference pressure. The present application avoids the low-temperature gas pressure measurement uncertainty caused by factors such as thermal molecular pressure difference effect in the traditional method, and solves the problem of temperature measurement accuracy restriction caused by pressure measurement under low temperature and low pressure.

Description

Technical Field

[0001] This invention relates to the field of temperature measurement technology, and in particular to a gas reference temperature measurement method and apparatus based on in-situ pressure measurement. Background Technology

[0002] Thermodynamic temperature is a fundamental physical quantity in the International System of Units (SI), with the unit Kelvin (K). Accurate temperature measurement plays a fundamental supporting role in scientific research, production, and daily life. Temperature values ​​used in practical applications all originate from thermodynamic temperature values ​​measured directly according to the Kelvin definition using benchmark-level temperature measurement methods, and from the international temperature scale defined based on these values. Therefore, accurate and reliable benchmark-level temperature measurement methods are of fundamental importance.

[0003] In the cryogenic region below the triple point of water (273.16 K), gas thermometry based on the gas temperature-pressure-density state relationship is currently the most accurate benchmark-level thermometry method. It obtains the temperature value by accurately measuring the gas pressure and density. The effective implementation of gas thermometry relies on the working fluid remaining in a gaseous state. However, in the temperature range below 5 K, even the least liquefied gas (helium) can liquefy (helium-4 critical temperature 5.2 K, helium-3 critical temperature 3.2 K). Below the critical temperature, to maintain the working fluid's gaseous state, the working fluid pressure must be controlled below its saturated vapor pressure. For example, at 2 K, the helium-4 working fluid pressure needs to be below 3.1 kPa (approximately 1 / 30th of atmospheric pressure) to maintain a gaseous state, while at 1 K, the helium-4 working fluid pressure needs to be below 0.1 kPa (approximately 1 / 1000th of atmospheric pressure). This necessitates operating at a low pressure. In traditional gas thermometry schemes, a high-precision pressure gauge is typically used to measure the pressure at room temperature, and the cryogenic pressure is obtained through accurate correction of the room temperature-cryogenic pressure difference. However, when the working pressure enters the low-pressure region, the scheme faces severe challenges: on the one hand, the relative uncertainty of low-pressure measurement increases significantly; on the other hand, the thermal molecular pressure difference effect is enhanced under low pressure, while the reliability and accuracy of existing empirical correction models are seriously insufficient, making pressure measurement a key bottleneck and the main source of uncertainty restricting the temperature measurement of gas reference levels below 5K.

[0004] To reduce the impact of pressure uncertainty on temperature measurement, existing research has proposed a relative gas thermometry method based on constant pressure. By introducing a known reference temperature and measuring the density of the thermometric medium at the same constant pressure under both the measured and reference temperatures, a constant pressure ratio thermometry working equation is constructed. This can reduce the accuracy requirements of pressure measurement in gas thermometry to some extent. However, this method only "reduces" rather than "eliminates" the contribution of pressure measurement to temperature measurement; accurate gas pressure measurement is still required in temperature measurement, and pressure measurement still limits the accuracy of temperature measurement. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention proposes a gas reference temperature measurement method based on in-situ pressure measurement, which can avoid the uncertainty in low-temperature gas pressure measurement caused by factors such as the thermomolecular pressure difference effect in traditional methods, and solve the problem of pressure measurement restricting the accuracy of temperature measurement under low temperature and low pressure.

[0006] The present invention also proposes a gas reference temperature measuring device based on in-situ pressure measurement.

[0007] The gas reference temperature measurement method based on in-situ pressure measurement according to an embodiment of the present invention includes: The temperature in the measuring chamber is at a known reference temperature. Under the condition of obtaining the working gas at a known reference pressure The first density signal below; Maintain the reference temperature Under constant conditions, obtain the working gas at the pressure to be measured. The second density signal below; The measuring chamber is under the pressure to be measured. and the temperature to be measured In this case, the third density signal of the working gas is obtained; Based on the first density signal, the second density signal, and the third density signal, and the reference temperature and the reference pressure Determine the temperature to be measured .

[0008] According to one embodiment of the present invention, the method is based on the first density signal, the second density signal, and the third density signal, as well as the reference temperature. and the reference pressure Determine the temperature to be measured The steps include: Based on the first density signal and the second density signal, an information about the pressure to be measured is established. The constant temperature and pressure measurement equation; Based on the second density signal and the third density signal, an information about the temperature to be measured is established. The constant pressure temperature measurement equation; Based on the isothermal pressure measurement equation and the isothermal pressure measurement equation, the pressure to be measured is determined. and the temperature to be measured .

[0009] According to one embodiment of the present invention, the pressure to be measured is determined based on the isothermal pressure measurement equation and the isothermal pressure measurement equation. and the temperature to be measured The steps include: The pressure to be measured can be obtained by simultaneously solving the isothermal pressure measurement equation and the isothermal pressure measurement equation. and the temperature to be measured ; Alternatively, based on the first density signal, the second density signal, and the reference pressure. and the reference temperature The pressure to be measured is obtained by solving the isothermal pressure measurement equation. ; Based on the pressure to be measured The second density signal and the third density signal are used to solve for the temperature to be measured using the constant pressure temperature measurement equation. .

[0010] According to one embodiment of the present invention, the isothermal pressure measurement equation is: In the isothermal pressure measurement equation, This is the first density signal. This is the second density signal. For reference pressure, For the pressure to be measured, For reference temperature, Represents the reference pressure and the reference temperature The theoretical density signal below, Represents the pressure to be measured and the reference temperature The theoretical density signal is below.

[0011] According to an embodiment of the present invention, the ratio term in the isothermal pressure equation The ratio of gas refractive indices The ratio of the squares of the refractive indices of gases The ratio of the square of the refractive index of the gas to 1 One of them; among them, For the working gas at the reference temperature and the pressure to be measured The refractive index below, For the working gas at the reference temperature and the reference pressure The refractive index below.

[0012] According to one embodiment of the present invention, the constant pressure temperature measurement equation is: In the constant pressure temperature measurement equation, This is the second density signal. It is a third-density signal. For the pressure to be measured, For reference temperature, The temperature to be measured. Represents the pressure to be measured and the reference temperature The theoretical density signal below, Represents the pressure to be measured and the temperature to be measured The theoretical density signal is below.

[0013] According to one embodiment of the present invention, it further includes: The temperature in the measuring chamber stabilizes at the known reference temperature. In the case of vacuum, the vacuum density signal of the measuring chamber under vacuum is obtained; wherein, the first density signal, the second density signal and the third density signal are all relative values ​​to the vacuum density signal.

[0014] According to one embodiment of the present invention, the density measurement signal is a physical quantity characterizing the refractive index or dielectric constant of the working gas, and the density measurement signal includes a first density signal, a second density signal and a third density signal.

[0015] According to an embodiment of the present invention, a gas reference temperature measuring device based on in-situ pressure measurement performs temperature measurement using any of the above-described gas reference temperature measuring methods based on in-situ pressure measurement, including: A low-temperature thermostat has a thermostatic cavity inside. A measuring chamber is arranged inside the constant temperature cavity; The reference pressure detection unit is located on the outside of the cryogenic thermostat; The connecting tube is connected at one end to the measuring chamber and at the other end to the reference pressure detection unit; A gas density detection unit is installed inside the measurement chamber; A reference temperature detection unit is installed in the measurement chamber.

[0016] According to one embodiment of the present invention, the reference pressure detection unit includes at least one of a reference-grade gas piston pressure gauge, a quartz crystal pressure gauge, or a capacitive thin-film pressure gauge; The gas density detection unit includes at least one of a Fabry-Perot optical interferometer cavity, a microwave resonant cavity, or a capacitor.

[0017] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: By constant reference temperature The first and second density signals measured below are compared with the reference pressure measured at room temperature. The value is transmitted to the measured pressure at the low temperature end. This enables the control of low pressure. The pressure value is determined in situ. Subsequently, the temperature determination process is based on this in-situ determined pressure value, so that the temperature measurement result no longer depends on the measurement of external low pressure. This avoids the uncertainty in low-temperature gas pressure measurement caused by factors such as the thermal molecular pressure difference effect in traditional methods, and solves the problem of pressure measurement restricting the accuracy of temperature measurement under low temperature and low pressure.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention and are not considered as limitations on this application. Moreover, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the gas reference temperature measuring device based on in-situ pressure measurement provided by the present invention.

[0021] Figure 2 This is one of the flowcharts of the gas reference temperature measurement method based on in-situ pressure measurement provided by the present invention.

[0022] Figure 3 This is the second schematic diagram of the gas reference temperature measurement method based on in-situ pressure measurement provided by the present invention.

[0023] Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0024] Figure label: 1. Reference pressure detection unit; 2. Low temperature thermostat; 3. Connecting pipe; 4. Measuring chamber; 5. Gas density detection unit; 6. Reference temperature detection unit; 7. Working gas; 810, Processor; 820, Communication interface; 830, Memory; 840, Communication bus. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] Furthermore, features specified as "first" or "second" may explicitly or implicitly include one or more of those features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified. In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, B1 and / or B2 can represent: B1 existing alone, B1 and B2 existing simultaneously, and B2 existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] like Figure 1 As shown, the first aspect of the present invention provides a gas reference temperature measuring device based on in-situ pressure measurement, which includes a low-temperature thermostat 2, a measuring chamber 4, a reference pressure detection unit 1, a connecting pipe 3, a gas density detection unit 5, and a reference temperature detection unit 6.

[0029] The low-temperature thermostat 2 has a constant temperature cavity inside, and the measuring chamber 4 is arranged inside the constant temperature cavity. The low-temperature thermostat 2 is used to provide a low-temperature environment for the measuring chamber 4, which can realize precise control and stable adjustment of the temperature of the measuring chamber 4, and provide stable temperature conditions for subsequent measurements at specific reference temperatures and the temperature to be measured, thus ensuring the accuracy and repeatability of the measurement.

[0030] The reference pressure detection unit 1 is located outside the cryogenic thermostat 2, which allows the reference pressure detection unit 1 to operate in a suitable room temperature environment, avoiding the influence of low temperature on the accuracy of pressure measurement, and thus enabling the use of a high-accuracy pressure gauge to obtain a reliable reference pressure value.

[0031] One end of the connecting pipe 3 is connected to the measuring chamber 4, and the other end is connected to the reference pressure detection unit 1. This connection method establishes a gas passage and pressure transmission path between the room temperature end and the low temperature measuring chamber 4, providing a physical basis for transmitting the reference pressure value measured at the room temperature end to the measuring chamber 4.

[0032] One end of the inlet pipe (low-temperature end) is connected to the measuring chamber 4, and the other end (room temperature end) is connected to the gas source. The gas source introduces the working gas 7 into the measuring chamber 4 through the inlet pipe. The exhaust pipe is connected to the measuring chamber 4 and is equipped with an exhaust valve for discharging gas. The coordinated arrangement of the gas source and the exhaust valve allows for precise filling and adjustment of the pressure inside the measuring chamber 4, thereby enabling the establishment and control of the reference pressure and the pressure to be measured.

[0033] The gas density detection unit 5 is installed inside the measuring chamber 4, enabling in-situ, real-time measurement of the density signal of the cryogenic working gas 7 within the measuring chamber 4. This avoids the measurement uncertainties introduced by thermal molecular effects and other factors in traditional external pressure measurement methods. The reference temperature detection unit 6 is installed in the measuring chamber 4, used to directly and accurately monitor the temperature of the measuring chamber 4 to ensure temperature control accuracy during constant-temperature pressure measurement and constant-pressure temperature measurement, and to provide a reference temperature for constant-pressure temperature measurement.

[0034] Optionally, the reference temperature detection unit 6 is a calibrated temperature sensor. Using a calibrated temperature sensor can provide an accurate and traceable reference temperature value for the temperature measurement method of this embodiment, providing a reliable temperature value for subsequent pressure measurement at a constant reference temperature and temperature calculation based on the reference temperature.

[0035] Understandably, a calibrated temperature sensor is capable of accurately measuring temperature at low temperatures (e.g., 4.2K).

[0036] Optionally, the reference pressure detection unit 1 includes at least one of a reference-grade gas piston pressure gauge, a quartz crystal pressure gauge, or a capacitive thin-film pressure gauge. Using these high-accuracy pressure gauges as the reference pressure detection unit 1 results in low uncertainty when measuring the initial reference pressure at room temperature, providing a high-precision initial value for subsequently transferring accurate pressure values ​​to the low-pressure target at the cryogenic end via the isothermal density ratio relationship.

[0037] Optionally, the gas density detection unit 5 includes at least one of a Fabry-Perot optical interferometer cavity, a microwave resonant cavity, or a capacitor. Using these gas density-sensitive devices as gas density measurement units enables in-situ accurate measurement of physical quantities characterizing gas density (such as refractive index or dielectric constant), thereby obtaining the fundamental measurement signals required for isothermal and pressure-based calculations.

[0038] The following description uses the control device as the executing entity to illustrate the gas reference temperature measurement method based on in-situ pressure measurement provided in this embodiment of the invention.

[0039] like Figure 2 As shown, a specific embodiment of the second aspect of the present invention provides a gas reference temperature measurement method based on in-situ pressure measurement, comprising the following steps: S210, The temperature in the measuring chamber is at a known reference temperature. Under the condition of obtaining the working gas at a known reference pressure The first density signal below.

[0040] Specifically, the control device is connected to the cryostat and the reference temperature detection unit, and the control device controls the cryostat and the reference temperature detection unit to maintain the temperature of the measuring chamber at the reference temperature. That is, the temperature value detected by the reference temperature detection unit is the reference temperature. By adjusting the cryogenic thermostat through the control device and receiving feedback from the reference temperature detection unit, the temperature of the measuring chamber can be precisely locked at the reference temperature, reducing the interference of temperature drift on subsequent density signal acquisition and providing stable temperature values ​​for pressure transmission and temperature calculation.

[0041] The control device activates the gas supply, injecting working gas into the measuring chamber through the inlet pipe. The control device is also connected to a reference pressure detection unit, which maintains the pressure at the reference pressure. Then, the control device shuts off the gas supply, at which point the measuring chamber is at the reference temperature. and reference pressure Under reference conditions, real-time monitoring by the reference pressure detection unit at room temperature accurately determines whether the pressure inside the measuring chamber has reached the preset reference value, ensuring the repeatability of the established reference state. Simultaneously, selecting a reference pressure higher than the pressure to be measured ensures that the measurement uncertainty is relatively low when using a high-accuracy pressure gauge at room temperature, thus providing an accurate initial reference for subsequent pressure value transfer.

[0042] Under reference conditions, the gas density detection unit acquires the first density signal of the working gas. The control device is connected to the gas density detection unit and obtains the working gas density signal at the reference temperature from the gas density detection unit. and reference pressure The first density signal is obtained from the gas density detection unit located inside the measurement chamber. This allows for in-situ acquisition of the density-related signal of the working gas, avoiding pressure difference correction errors introduced by external connecting pipelines and ensuring that the first density signal accurately reflects the gas density under the reference conditions.

[0043] S220, Maintain reference temperature Under constant conditions, obtain the working gas at the pressure to be measured. The second density signal below.

[0044] Specifically, the control device controls the cryostat to maintain the temperature of the measuring chamber at the reference temperature. Unchanged. By continuously controlling the temperature, the temperature of the measuring chamber is kept constant during the depressurization process. This ensures that when constructing the isothermal density ratio, the temperature terms cancel each other out in the ratio, thereby eliminating the first-order effect of absolute temperature accuracy on the pressure measurement results.

[0045] The control device, in conjunction with an external pressure control system, causes the pressure inside the measuring chamber to change from the reference pressure. Decrease to the pressure to be measured The pressure in the chamber to be measured stabilizes at the pressure to be measured. At that time, the gas density detection unit collects the working gas at the reference temperature. and the pressure to be measured The control device is connected to the gas density detection unit to acquire the second density signal. During the depressurization process, the gas is discharged through the exhaust valve, and the pressure change is gradual. The signal is acquired after the pressure stabilizes, ensuring the correspondence between the second density signal and the pressure state to be measured. This provides a data basis for subsequently transmitting the reference pressure value to the low pressure to be measured through the ratio relationship.

[0046] S230, The pressure to be measured is in the measuring chamber. and the temperature to be measured In this case, the third density signal of the working gas is obtained.

[0047] Specifically, the control device maintains the pressure in the measuring chamber at the pressure to be measured by linking with an external pressure control system. Simultaneously, the low-temperature thermostat is controlled to adjust the temperature of the measuring chamber, so that the temperature of the measuring chamber is adjusted from the reference temperature. Adjust to the temperature to be measured .

[0048] The measuring chamber stabilizes at the pressure to be measured. and the temperature to be measured Under these conditions, the gas density detection unit acquires the third density signal of the working gas, and the control device obtains the third density signal from the gas density detection unit. Signal acquisition occurs only after both temperature and pressure have reached a stable state, ensuring that the third density signal accurately reflects the gas density under the measured conditions and provides a reliable measurement value for subsequent constant pressure ratio temperature measurement.

[0049] S300, based on the first density signal, the second density signal, and the third density signal, and the reference temperature. and reference pressure Determine the temperature to be measured .

[0050] Specifically, the control device obtains the reference temperature from the reference temperature detection unit. The reference pressure is obtained from the reference pressure detection unit. The control device is based on the acquired first density signal, second density signal, third density signal, and reference temperature. and reference pressure Furthermore, by combining the built-in algorithms (such as performing step-by-step calculations or solving simultaneously using the isothermal density ratio and the isobaric density ratio), the temperature to be measured can be determined. .

[0051] In this embodiment, the reference pressure measured at room temperature is represented by a first density signal and a second density signal measured at a constant reference temperature. The value is transmitted to the measured pressure at the low temperature end. This enables the control of low pressure. The pressure value is determined in situ. Subsequently, the temperature determination process is based on this in-situ determined pressure value, so that the temperature measurement result no longer depends on the real-time measurement of the external low pressure. This avoids the uncertainty in low-temperature gas pressure measurement caused by factors such as the thermomolecular pressure difference effect in traditional methods, and solves the problem of pressure measurement restricting the accuracy of temperature measurement under low temperature and low pressure.

[0052] It should be noted that the gas reference temperature measurement method based on in-situ pressure measurement provided in this embodiment of the invention is applicable to temperatures below 5K and also to temperatures above 5K. That is, the control device is connected to a cryostat, and the control device adjusts the output power of the cryostat to ensure that the temperature of the measuring chamber reaches the set target value in both the temperature range below 5K and the temperature range above 5K.

[0053] In the low-temperature region below 5K, to ensure that the working fluid for temperature measurement is in a gaseous state, the working pressure needs to be maintained at an extremely low level below the saturated vapor pressure. At this time, the temperature measurement method of this embodiment transmits the higher reference pressure value, which is easy to measure accurately at room temperature, to the low pressure to be measured at the low-temperature end through the relationship of density signal ratio, thereby realizing the in-situ determination of the low pressure value. This technical solution eliminates the need for external real-time measurement of the extremely low pressure at the low-temperature end during the entire temperature measurement process, thereby avoiding the measurement uncertainty introduced by the thermomolecular pressure difference effect and its correction due to the significant temperature gradient in the connecting pipe in the traditional method. It solves the problem that pressure measurement becomes a bottleneck when performing gas temperature measurement in this temperature range in the existing technology.

[0054] In the temperature range above 5K, although the influence of the thermal molecular pressure difference effect is weakened, the temperature measurement method of this embodiment, as a gas reference temperature measurement scheme, still holds true in its principle of determining the temperature to be measured by measuring the density signals of three state points (reference temperature and reference pressure, reference temperature and pressure to be measured, and pressure to be measured and pressure to be measured). This provides a unified and inherently consistent measurement method for the entire temperature range in which the gas temperature measurement method is applicable.

[0055] Optionally, reference pressure The pressure is above 10 kPa. (Refer to the reference pressure.) Choosing a pressure higher than 10 kPa is advantageous because this pressure value is significantly higher than the low pressure to be measured. Within this pressure range, the reference pressure detection unit located at room temperature can perform measurements with lower relative uncertainty. Simultaneously, compared to extremely low pressures, this pressure level allows the thermal molecular pressure difference effect within the connecting tube between the room temperature end and the cryogenic measurement chamber to be negligible, thus simplifying the pressure correction process. Therefore, using a reference pressure of this order of magnitude provides an accurate and reliable initial pressure value for the subsequent step of transferring pressure values ​​through the isothermal density ratio.

[0056] In some embodiments of the present invention, S300 includes: S301. Based on the first density signal and the second density signal, the pressure to be measured is determined through the isothermal density ratio relationship. .

[0057] Specifically, the control device determines the pressure to be measured based on the first density signal and the second density signal, combined with the isothermal density ratio relationship. By establishing an equation relating the density signal ratio, the reference pressure precisely measured at room temperature is... The value is transmitted to the pressure to be measured in a low-temperature environment. This method enables in-situ determination of low-pressure values ​​within the measurement chamber. It avoids direct external measurement of low temperatures and pressures, thus preventing pressure correction uncertainties introduced into connecting pipes by factors such as gas thermal molecular effects, a problem common in traditional methods. Furthermore, because this isothermal density ratio utilizes ratio calculations, the result reduces the dependence on the reference temperature to a first-order degree. Dependence on absolute accuracy.

[0058] S302, based on the second density signal, the third density signal, and the pressure to be measured. The temperature to be measured is determined by the ratio of isobaric density. .

[0059] Specifically, the control device calculates the pressure to be measured based on the second density signal, the third density signal, and S301. By combining this with the isobaric density ratio, the temperature to be measured can be determined. Since the temperature is determined based on a known, in-situ constant pressure value within the system (i.e., the pressure to be measured). This eliminates the reliance on real-time external measurement of low temperatures and pressures in the temperature measurement process. This solves the technical bottleneck in traditional gas temperature measurement methods, where inaccurate low-pressure measurements directly limit the accuracy of the results, thus providing a new method for measuring the temperature. The determination of this provides a computational basis that is unaffected by the uncertainty of external pressure measurements.

[0060] like Figure 3 As shown, in some embodiments of the present invention, S300 includes: S310, Establish a system for the pressure to be measured based on the first density signal and the second density signal. The constant temperature and pressure measurement equation.

[0061] Specifically, the control device constructs a value about the pressure to be measured based on the first density signal and the second density signal, using the isothermal density ratio relationship. The isothermal pressure measurement equation is given by formula (1).

[0062] Formula (1).

[0063] In formula (1), This is the first density signal. For the second density signal, For reference pressure, For the pressure to be measured, For reference temperature, Representative in reference pressure and reference temperature The theoretical density signal below, Represents the pressure to be measured and reference temperature The theoretical density signal is below.

[0064] The establishment of this isothermal pressure measurement equation enables the use of a high-accuracy external reference pressure. The value of the quantity is transmitted to the low-pressure device under test through the ratio of the measurable first density signal and the second density signal. This allows for in-situ determination of gas pressure at the low-temperature end (i.e., the measurement chamber). Furthermore, because the equation uses a ratio form, the reference temperature... The main influences on pressure determination are eliminated in the calculation, reducing the dependence of pressure results on the absolute accuracy of the reference temperature.

[0065] Alternatively, since gas density is the refractive index The function of the isothermal pressure equation, therefore the ratio term of the equation (1) is a function of the isothermal pressure equation. The ratio of gas refractive indices The ratio of the squares of the refractive indices of gases The ratio of the square of the refractive index of the gas to 1 One of them. Among them, For the working gas at the reference temperature and the pressure to be measured The refractive index below, For the working gas at the reference temperature and reference pressure The refractive index at the specified value. The ratio term... This is specifically defined in a form related to refractive index, providing a feasible technical path for achieving high-sensitivity density signal acquisition using optical and other measurement methods.

[0066] S320, establishes a temperature measurement system based on the second and third density signals. The constant pressure temperature measurement equation.

[0067] Specifically, the control device constructs a value about the temperature to be measured based on the second density signal and the third density signal, using the isobaric density ratio relationship. The constant pressure temperature measurement equation is given by formula (2).

[0068] Formula (2).

[0069] In formula (2), This is the second density signal. It is a third-density signal. For the pressure to be measured, For reference temperature, The temperature to be measured. Represents the pressure to be measured and reference temperature The theoretical density signal below, Represents the pressure to be measured and the temperature to be measured The theoretical density signal is below.

[0070] The equation for constant pressure temperature measurement is established by utilizing the same pressure to be measured. The relationship between gas density signal and temperature is shown below. Since the isobaric thermometry equation uses a ratio form, the pressure to be measured... The main influences on temperature determination are eliminated in the calculation, making the measured temperature... The calculation results do not directly depend on the pressure being measured. The absolute value is not determined by the measurement itself, but by its constancy during the two measurement processes, which lays the foundation for subsequent simultaneous solutions.

[0071] Alternatively, since gas density is the refractive index The function of the constant pressure temperature measurement equation, therefore the ratio term of the equation (2) is... The ratio of gas refractive indices The ratio of the squares of the refractive indices of gases The ratio of the square of the refractive index of the gas to 1 One of them. Among them, For the working gas at the temperature to be measured and the pressure to be measured The refractive index below, For the working gas at the reference temperature and the pressure to be measured The refractive index below.

[0072] S330. Based on the isothermal pressure measurement equation and the isothermal temperature measurement equation, determine the pressure to be measured. and the temperature to be measured .

[0073] Optionally, the pressure to be measured is determined based on the isothermal pressure measurement equation and the isothermal pressure measurement equation. and the temperature to be measured The steps include: solving for the pressure to be measured by simultaneously solving the isothermal pressure measurement equation and the isothermal pressure measurement equation. and the temperature to be measured .

[0074] Specifically, the control device combines formulas (1) and (2) to solve for the pressure to be measured. and the temperature to be measured By solving a simultaneous equation, the pressure to be measured can be determined. and the temperature to be measured The two unknowns are solved within a unified system of equations. This approach treats the data acquired throughout the entire measurement process as a whole, providing a computational path that can determine the pressure and temperature to be measured in one go.

[0075] Optionally, the pressure to be measured is determined based on the isothermal pressure measurement equation and the isothermal pressure measurement equation. and the temperature to be measured The steps include: firstly, based on the first density signal, the second density signal, and the reference pressure... and the reference temperature The pressure to be measured is obtained by solving the isothermal pressure measurement equation. Then, based on the pressure to be measured... The second density signal and the third density signal are used to solve the constant pressure temperature measurement equation to obtain the temperature to be measured. .

[0076] This embodiment adopts a step-by-step calculation path. The control device first performs isothermal pressure measurement calculation, that is, based on the measured first density signal, second density signal, and known reference pressure. and reference temperature The pressure to be measured is obtained by first solving the equation (1). The determined value. This step separates the pressure determination process, and the calculated pressure to be measured is determined from this step. It is a clear intermediate result obtained by measuring the density signal in situ and passing the high pressure value down, thus avoiding the uncertainty introduced by direct external measurement of low temperature and low pressure.

[0077] Subsequently, the control device performs constant pressure and temperature measurement calculations, taking the pressure to be measured obtained in the previous step. As known inputs, along with the measured second and third density signals, are substituted into formula (2) to calculate the final temperature to be measured. .

[0078] In this embodiment, the pressure value used for temperature calculation originates from internal system transmission and calculation, rather than external real-time measurement, thus freeing the final temperature determination process from dependence on external low-pressure measurements. This step-by-step execution method has clear logical steps and facilitates the analysis of intermediate results (i.e., the pressure to be measured). The test was conducted to determine the final temperature to be measured. It provides a clear computation path.

[0079] It should be noted that S310 and S320 are not restrictions on the order. In other words, S310 and S320 can be performed simultaneously or sequentially.

[0080] like Figure 3 As shown, in some embodiments of the present invention, the gas reference temperature measurement method based on in-situ pressure measurement further includes: S100, The temperature in the measuring chamber stabilizes at a known reference temperature. Under these conditions, the vacuum density signal of the measurement chamber under vacuum is obtained.

[0081] Specifically, the control device is connected to the cryostat and the reference temperature detection unit, and the control device controls the cryostat and the reference temperature detection unit to maintain the temperature of the measuring chamber at the reference temperature. That is, the temperature value detected by the reference temperature detection unit is the reference temperature. This ensures that the temperature conditions for acquiring the vacuum density signal are consistent with those for acquiring the first and second density signals, providing a comparable benchmark for accurately subtracting the background signal.

[0082] The control device starts the vacuum pump connected to the connecting pipe, which evacuates the measuring chamber to a vacuum state through the connecting pipe. This process creates conditions for obtaining a zero-point reference signal. Optionally, the measuring chamber is evacuated to a pressure less than 10... -4 A vacuum state of Pa, this pressure level can control the influence of residual gas on background signal measurement within a specific range.

[0083] Under vacuum conditions, the gas density detection unit acquires the vacuum density signal of the working gas. This vacuum density signal reflects the physical characteristics of the gas density detection unit itself when there is no working gas, acting as a background value. Subsequently, the control device connects to the gas density detection unit and acquires this vacuum density signal from it. The purpose of the control device acquiring this vacuum density signal is to subtract this background value from the acquired first, second, and third density signals in subsequent data processing, thereby obtaining a net signal contributed only by the working gas and improving the accuracy of subsequent calculations.

[0084] Optionally, the first, second, and third density signals are all relative values ​​to the vacuum density signal. That is, the density signals used for subsequent calculations are not the raw signals directly acquired by the gas density detection unit, but rather signals that have undergone background subtraction processing. The vacuum density signal characterizes the physical characteristics output of the gas density detection unit and the measuring chamber system itself in the absence of a working gas. By removing this vacuum density signal from the raw signals obtained from each measurement, the influence of the background signal inherent in the system and unrelated to the working gas density can be eliminated. This allows the net signal used for calculation to more accurately reflect the signal change caused by the change in working gas density, improving the accuracy of the finally determined temperature.

[0085] In some embodiments of the present invention, the density measurement signal is a physical quantity characterizing the refractive index or dielectric constant of the working gas. The density measurement signal includes a first density signal, a second density signal, and a third density signal. Since there is a definite physical relationship between the refractive index or dielectric constant of the working gas and its density, defining the density measurement signal as a signal characterizing these two physical quantities provides a theoretical basis for indirectly reflecting the gas density by measuring these physical quantities. This approach enables the use of mature measurement technologies, such as optical or electrical methods, to perform in-situ, high-sensitivity detection of the state of the working gas inside the measurement chamber, thereby obtaining accurate first, second, and third density signals, providing reliable data input for subsequent precise calculations based on ratio relationships.

[0086] Among them, the physical quantities characterizing the refractive index of the working gas include the refractive index of the working gas, the square of the refractive index of the working gas, or the square of the refractive index of the working gas minus 1.

[0087] It is understandable that the vacuum density signal is the background signal measured by the gas density detection unit under vacuum conditions, and its physical dimensions are the same as those of the signal characterizing the density change of the working gas.

[0088] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4 As shown, the electronic device may include a processor 810, a communications interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communications interface 820, and the memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute the following methods: The temperature in the measuring chamber is at a known reference temperature. Under the condition of obtaining the working gas at a known reference pressure The first density signal below; Maintain reference temperature Under constant conditions, obtain the working gas at the pressure to be measured. The second density signal below; The measuring chamber is under the pressure to be measured. and the temperature to be measured In this case, the third density signal of the working gas is obtained; Based on the first density signal, the second density signal, and the third density signal, as well as the reference temperature and reference pressure Determine the temperature to be measured .

[0089] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to related technologies, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0090] On the other hand, embodiments of the present invention disclose a computer program product, the computer program product including a computer program stored on a non-transitory computer-readable storage medium, the computer program including program instructions, and when the program instructions are executed by a computer, the computer can perform the methods provided in the above-described method embodiments, such as including: The temperature in the measuring chamber is at a known reference temperature. Under the condition of obtaining the working gas at a known reference pressure The first density signal below; Maintain reference temperature Under constant conditions, obtain the working gas at the pressure to be measured. The second density signal below; The measuring chamber is under the pressure to be measured. and the temperature to be measured In this case, the third density signal of the working gas is obtained; Based on the first density signal, the second density signal, and the third density signal, as well as the reference temperature and reference pressure Determine the temperature to be measured .

[0091] In another aspect, embodiments of the present invention also provide a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the methods provided in the above embodiments, including, for example: The temperature in the measuring chamber is at a known reference temperature. Under the condition of obtaining the working gas at a known reference pressure The first density signal below; Maintain reference temperature Under constant conditions, obtain the working gas at the pressure to be measured. The second density signal below; The measuring chamber is under the pressure to be measured. and the temperature to be measured In this case, the third density signal of the working gas is obtained; Based on the first density signal, the second density signal, and the third density signal, as well as the reference temperature and reference pressure Determine the temperature to be measured .

[0092] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0093] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0094] Finally, it should be noted that the above embodiments are only for illustrating the present invention and not for limiting the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be covered within the scope of the claims of the present invention.

Claims

1. A gas reference temperature measurement method based on in-situ pressure measurement, characterized in that, include: The temperature in the measuring chamber is at a known reference temperature. Under the condition of obtaining the working gas at a known reference pressure The first density signal below; Maintain the reference temperature Under constant conditions, obtain the working gas at the pressure to be measured. The second density signal below; The measuring chamber is under the pressure to be measured. and the temperature to be measured In this case, the third density signal of the working gas is obtained; Based on the first density signal, the second density signal, and the third density signal, and the reference temperature and the reference pressure Determine the temperature to be measured .

2. The gas reference temperature measurement method based on in-situ pressure measurement according to claim 1, characterized in that, The density signals are based on the first density signal, the second density signal, and the third density signal, as well as the reference temperature. and the reference pressure Determine the temperature to be measured The steps include: Based on the first density signal and the second density signal, an information about the pressure to be measured is established. The constant temperature and pressure measurement equation; Based on the second density signal and the third density signal, an information about the temperature to be measured is established. The constant pressure temperature measurement equation; Based on the isothermal pressure measurement equation and the isothermal pressure measurement equation, the pressure to be measured is determined. and the temperature to be measured .

3. The gas reference temperature measurement method based on in-situ pressure measurement according to claim 2, characterized in that, The pressure to be measured is determined based on the isothermal pressure measurement equation and the isothermal pressure measurement equation. and the temperature to be measured The steps include: The pressure to be measured can be obtained by simultaneously solving the isothermal pressure measurement equation and the isothermal pressure measurement equation. and the temperature to be measured ; Alternatively, based on the first density signal, the second density signal, and the reference pressure. and the reference temperature The pressure to be measured is obtained by solving the isothermal pressure measurement equation. ; Based on the pressure to be measured The second density signal and the third density signal are used to solve for the temperature to be measured using the constant pressure temperature measurement equation. .

4. The gas reference temperature measurement method based on in-situ pressure measurement according to claim 2, characterized in that, The isothermal pressure measurement equation is as follows: In the isothermal pressure measurement equation, This is the first density signal. This is the second density signal. For reference pressure, For the pressure to be measured, For reference temperature, Represents the reference pressure and the reference temperature The theoretical density signal below, Represents the pressure to be measured and the reference temperature The theoretical density signal is below.

5. The gas reference temperature measurement method based on in-situ pressure measurement according to claim 4, characterized in that, The ratio term in the isothermal pressure measurement equation The ratio of gas refractive indices The ratio of the squares of the refractive indices of gases The ratio of the square of the refractive index of the gas to 1 One of them; among them, For the working gas at the reference temperature and the pressure to be measured The refractive index below, For the working gas at the reference temperature and the reference pressure The refractive index below.

6. The gas reference temperature measurement method based on in-situ pressure measurement according to claim 2, characterized in that, The constant-pressure temperature measurement equation is as follows: In the constant pressure temperature measurement equation, This is the second density signal. It is a third-density signal. For the pressure to be measured, For reference temperature, The temperature to be measured. Represents the pressure to be measured and the reference temperature The theoretical density signal below, Represents the pressure to be measured and the temperature to be measured The theoretical density signal is below.

7. The gas reference temperature measurement method based on in-situ pressure measurement according to any one of claims 1 to 6, characterized in that, Also includes: The temperature in the measuring chamber stabilizes at the known reference temperature. In the case of vacuum, the vacuum density signal of the measuring chamber under vacuum is obtained; wherein, the first density signal, the second density signal and the third density signal are all relative values ​​to the vacuum density signal.

8. The gas reference temperature measurement method based on in-situ pressure measurement according to any one of claims 1 to 6, characterized in that, The density measurement signal is a physical quantity characterizing the refractive index or dielectric constant of the working gas, and the density measurement signal includes the first density signal, the second density signal and the third density signal.

9. A gas reference temperature measuring device based on in-situ pressure measurement, characterized in that, The gas reference temperature measurement method based on in-situ pressure measurement as described in any one of claims 1 to 8 includes: Low-temperature thermostat (2) has a thermostatic cavity inside; The measuring chamber (4) is arranged inside the constant temperature chamber; The reference pressure detection unit (1) is located outside the low-temperature thermostat (2); The connecting pipe (3) is connected at one end to the measuring chamber (4) and at the other end to the reference pressure detection unit (1); A gas density detection unit (5) is installed inside the measuring chamber (4); A reference temperature detection unit (6) is installed in the measuring chamber (4).

10. The gas reference temperature measuring device based on in-situ pressure measurement according to claim 9, characterized in that, The reference pressure detection unit (1) includes at least one of a reference-grade gas piston pressure gauge, a quartz crystal pressure gauge, or a capacitive thin-film pressure gauge. The gas density detection unit (5) includes at least one of a Fabry-Perot optical interference cavity, a microwave resonant cavity, or a capacitor.

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