CN106768471A - A kind of non-contact type temperature measurement method based on pressure broadening - Google Patents

Abstract

The present invention relates to a kind of non-contact type temperature measurement method based on pressure broadening, the alkali metal air chamber filled with a kind of gas is heated to a certain laser absorption spectrum treated testing temperature, measure alkali metal atom first；Spectral line to measuring is fitted by theoretical formula, obtains pressure broadening；Finally, according to the corresponding relation of temperature and pressure broadening, obtain treating testing temperature.Irradiated by alkali metal air chamber to diverse location by adjusting laser, measure the temperature of alkali metal plenum interior diverse location, and then measure thermograde.Suitable for the measurement of alkali metal plenum interior temperature, compensate for the contact type temperature measuring such as traditional thermal resistance method can not carry out the deficiency of accurate measurement to the present invention to alkali metal plenum interior temperature and thermograde.Can be applied to the temperature survey of the inside of air chamber employed in the instruments such as atom magnetometer, atomic spin gyroscope.

Description

A kind of non-contact type temperature measurement method based on pressure broadening

Technical field

The present invention relates to a kind of non-contact type temperature measurement method based on pressure broadening, can be used for atom magnetometer, original The measurement of the alkali metal plenum interior temperature in the instruments such as sub- spin gyroscope.

Background technology

Alkali metal air chamber is the core Sensitive Apparatus of the quantum measuring instrument such as atom magnetometer, atomic gyroscope.Alkali metal The accurate detection of plenum interior temperature is to realize the premise of alkali metal internal temperature high-precision control.The sensitivity of atom magnetometer It is closely related with the polarizability of alkali metal atom with the drift of atom laser gyroscope, and the polarizability temperature influence of alkali metal atom. It is therefore proposed that a kind of method for detecting alkali metal plenum interior temperature has great importance.

Existing non-contact temperature measuring method also has IR thermometry, and advantage is that it need not touch dut temperature Internal or surface, therefore, without interference with the state of dut temperature, temperature measurer is not also damaged by temperature field in itself；But limit In measurement object external temperature, it has not been convenient to measure interior of articles temperature, while easily by the shadow of environmental factor such as temperature, dust etc. Ring.Existing frequently-used alkali metal air chamber detection method using the contact type temperature measuring method such as thermal resistance, can only measure baking box with And the temperature of alkali metal air chamber wall, it is impossible to it is accurately obtained the temperature of alkali metal plenum interior, it is impossible to realize alkali metal gas Indoor Temperature The precise control of degree, this can cause very big influence to the polarizability of alkali metal atom, and then influence atom magnetometer and sensitive The drift of degree and atom laser gyroscope.

The content of the invention

The present invention solve problem be：Overcome the shortcomings of existing conventional method, the method based on pressure broadening, there is provided a kind of The method of measurable alkali metal plenum interior temperature, improves the certainty of measurement of gas indoor temperature.

Technical solution of the invention is：A kind of method of the non-contact type temperature measurement based on pressure broadening, the party A kind of alkali metal air chamber filled with gas is heated to a certain laser absorption light treated testing temperature, measure alkali metal atom by method first Spectrum；Spectral line to measuring is fitted by theoretical formula, obtains pressure broadening；Finally, according to the right of temperature and pressure broadening Should be related to, obtain treating testing temperature.Irradiated by alkali metal air chamber to diverse location, in measurement alkali metal air chamber by adjusting laser The temperature of portion's diverse location, and then measure thermograde.

Its concrete methods of realizing and step are as follows：

(1) heating alkali metal air chamber treats testing temperature to a certain；

(2) DBR laser using wavelength tuning range near alkali metal atom D1 lines, DBR laser is exported Laser is irradiated in alkali metal air chamber and frequency sweep, measures the transmitance of different frequency incident laser, bent so as to calculate optical depth Line, then carries out Lorentzian fitting to optical depth curve, obtains the spectral line pressure broadening Γ of D1 lines；

(3) using known gas in known temperature T₀Under the alkali metal D1 line pressure broadenings Γ that causes₀And step (2) The Γ of acquisition_TCalculate and treat testing temperature T, the formula for using for：

T₀It is known temperature, Γ₀It is temperature T₀The alkali metal D1 line pressure broadenings that lower gas causes, the value of the two parameters It is known, Γ_TIt is the alkali metal D1 line pressure broadening that causes of the known gas in the case where testing temperature T is treated, is that actual measurement is obtained 's；N is temperature dependency, or temperature coefficient, and value can and different, conventional alkali different with the species of gas with alkali metal The value of metal and inert gas is 0.3 to 0.5；

(4) laser irradiation is changed by alkali metal air chamber position, repeat step (1)-(3) measure alkali metal air chamber respectively Perpendicular to the pressure broadening of plane diverse location where laser direction, conversion obtains temperature, and then measures whole alkali metal air chamber Interior Temperature Distribution, using the different temperatures of plenum interior diverse location, obtains alkali metal air chamber thermograde；

Filled with one or more gas in described alkali metal air chamber, and the pressure broadening value that gas causes is much larger than certainly Right broadening and dopplerbroadening.

Optical depth curve computing formula in the step (2) is：

Wherein, υ is the frequency of incident laser, I_outAnd I_inThe respectively light intensity of the outgoing of alkali metal air chamber and incident laser.

Lorentzian in the step (2) is：

Wherein, k is proportionality coefficient, and υ is laser frequency, υ₀Centered on frequency, Γ is that spectral line pressure broadening, i.e. Lorentz are bent The full width at half maximum of line, δ is frequency displacement.

The computing formula of the thermograde in the step (4) is：

WhereinBe thermograde on vertical laser direction plane, define xoy planes be perpendicular to laser direction plane, The distance that △ x, △ y are x, y side moves up, △ T are temperature variation.

Principle of the invention is：The absorption line of alkali metal atom has certain width, is deposited without other gases There is nature broadening and dopplerbroadening in case.When there is gas in air chamber, spectral line occurs pressure broadening, and Pressure broadening is much larger than nature broadening and dopplerbroadening, therefore only considers pressure broadening.The size of pressure broadening is deposited with temperature In functional relation, when gas temperature changes in air chamber, pressure broadening can be varied with temperature.In known gas, alkali metal is special Pressure broadening is different, each fine energy that existing many pertinent literatures cause to temperature in the different temperature of fixed fine-structure levels The pressure broadening value of level spectral line carried out detailed measurements.Therefore, by measuring the spectral line of alkali metal fine-structure levels at temperature to be measured Broadening, further according to the known measurement in document, it is possible to calculate and treat testing temperature.

Present invention advantage compared with prior art is：A fine-structure levels by measuring alkali metal atom of the invention D1 line pressure broadenings, according to the spectral line pressure broadening that filled known gas cause under known temperature, calculate and treat testing temperature, more In having mended the conventional contact thermometry such as thermal resistance, it is impossible to measure the deficiency of alkali metal plenum interior temperature, improve The certainty of measurement of gas indoor temperature.

Brief description of the drawings

Fig. 1 is measuring method flow chart of the invention；

Fig. 2 is the experimental provision schematic diagram of laser absorption spectrum measurement in the present invention.

Specific embodiment

The present invention obtains phase by measuring the laser absorption spectral line of alkali metal atom D1 lines, and carrying out theoretical fitting to spectral line The pressure broadening answered, the temperature of alkali metal plenum interior is calculated further according to the relation between temperature and pressure broadening.Alkali metal There is certain volume in air chamber, traditional contact measurement method can only measure temperature sensor contact on alkali metal air chamber wall Temperature on area, it is impossible to measure the temperature inside alkali metal, contact type measurement is needed alkali metal air chamber built-in sensors, this For being no practical significance for atom magnetometer, atomic spin gyroscope.Thermometry based on pressure broadening, This problem can be solved, alkali metal internal temperature is measured.Meanwhile, irradiated by alkali metal air chamber position by changing laser, Perpendicular to the pressure broadening of laser direction diverse location, conversion obtains temperature to measurement alkali metal air chamber, and then measures whole respectively Temperature Distribution in alkali metal air chamber, obtains thermograde.

As shown in figure 1, specific implementation step of the invention is as follows：

(1) the alkali metal air chamber filled with one or more gas to be measured is installed in experimental system as shown in Figure 2, It is heated to a certain temperature to be measured.

Laser 1 uses DBR laser of the tunable range near alkali metal atom D1 lines first, the laser of its output ByIt is divided into two-beam after wave plate 3 and polarization splitting prism 4, a branch of to transmit to wavemeter 2 to measure its frequency, another beam is passed Transport to Amici prism 5.The light beam of Amici prism enters low pressure reference gas chamber 10, then enters data by photodetector 12 Acquisition system 14, for demarcating centre frequency, after another light beam enters chopper 6, is modulated, by a splitting ratio to light It is 1:1 depolarization Amici prism 7, it is a branch of to be demodulated into two-way lock-in amplifier 13 by photodetector 11, to subtract The influence of veiling glare in subenvironment, finally enters data collecting system 14, and another beam is by the alkali metal gas filled with a kind of gas Behind room 8, it is demodulated into two-way lock-in amplifier 13 by photodetector 9, finally enters data collecting system 14.

(2) by the output of laser 1 near alkali metal atom D1 lines frequency sweep, record corresponding laser frequency v and light The output I of electric explorer_inAnd I_out, so as to realize the measurement of absorption line.Alkali metal air chamber 8 is calculated according to experimental data Optical depth curve OD (v) formula is as follows：

Data fitting is carried out to OD (v) using Lorentzian, fitting formula is as follows：

Wherein, k is proportionality coefficient, and υ is laser frequency, υ₀Centered on frequency, Γ is that spectral line pressure broadening, i.e. Lorentz are bent The full width at half maximum of line, δ is frequency displacement.

(3) using known gas in known temperature T₀Under the alkali metal D1 line pressure broadenings Γ that causes₀And step (2) is obtained Γ calculate and treat testing temperature T, the formula for using for：

N is temperature dependency, or temperature coefficient, and value can be different with the species of gas and different with alkali metal, often The value of alkali metal and inert gas is 0.3 to 0.5.

(4) laser irradiation is changed by alkali metal air chamber position, repeat step (1)-(3) measure alkali metal air chamber respectively Perpendicular to the pressure broadening of plane diverse location where laser direction, conversion obtains temperature, and then measures whole alkali metal air chamber Interior Temperature Distribution, using the different temperatures of plenum interior diverse location, obtains alkali metal air chamber thermograde.

The content not being described in detail in description of the invention belongs to prior art known to professional and technical personnel in the field.

Claims (5)

1. a kind of non-contact type temperature measurement method based on pressure broadening, it is characterised in that comprise the following steps：

(1) heating alkali metal air chamber treats testing temperature to a certain；

(2) the Distributed Bragg Reflection laser (DBRL) using wavelength tuning range near alkali metal atom D1 lines, will The laser of DBR laser output is irradiated in alkali metal air chamber and carries out frequency sweep, measures the transmitance of different frequency incident laser, from And optical depth curve is calculated, and Lorentzian fitting is then carried out to optical depth curve, obtain the spectral line pressure of D1 lines Broadening Γ；

(3) using this kind of gas in temperature T₀Under the alkali metal D1 line pressure broadenings Γ that causes₀And the Γ that step (2) is obtained_TMeter Calculate and treat testing temperature T, the formula for using for：

$\frac{{\mathrm{\Γ}}_0}{{\mathrm{\Γ}}_T}={\left(\frac{T_0}{T}\right)}^n$

T₀It is known temperature, Γ₀It is temperature T₀The alkali metal D1 line pressure broadenings that lower gas causes, the value of the two parameters is Know, Γ_TIt is the alkali metal D1 line pressure broadening that causes of the known gas in the case where testing temperature T is treated, actual measurement is obtained；n It is temperature dependency, or temperature coefficient, value is 0.3 to 0.5；

(4) laser irradiation is changed by alkali metal air chamber position, repeat step (1)-(3) measure alkali metal air chamber vertical respectively The pressure broadening of plane diverse location where laser direction, conversion obtains temperature, and then measures in whole alkali metal air chamber Temperature Distribution, using the different temperatures of plenum interior diverse location, obtains alkali metal air chamber thermograde.

2. the method for a kind of non-contact type temperature measurement based on pressure broadening according to claim 1, it is characterised in that： The computing formula of the thermograde in the step (4) is：

$\▿T=(\frac{\∂T}{\∂x},\frac{\∂T}{\∂y})\stackrel{\lim \mathrm{\Δ}x\→0\mathrm{\Δ}y\→0}{=}(\frac{\mathrm{\Δ}T}{\mathrm{\Δ}x},\frac{\mathrm{\Δ}T}{\mathrm{\Δ}y})$

WhereinIt is thermograde on vertical laser direction plane, it is perpendicular to laser direction plane, △ x, △ to define xoy planes The distance that y is x, y side moves up, △ T are temperature variation.

3. the method for a kind of non-contact type temperature measurement based on pressure broadening according to claim 1, it is characterised in that： Filled with a kind of gas in alkali metal air chamber in the step (1), pressure broadening is far longer than nature broadening and dopplerbroadening, While pressure broadening temperature influence.

4. the method for a kind of non-contact type temperature measurement based on pressure broadening according to claim 1, it is characterised in that： Optical depth curve computing formula in the step (2) is：

$OD\left(\mathrm{\υ}\right)=-ln\frac{I_{out}}{I_{in}}$

Wherein, υ is the frequency of incident laser, I_outAnd I_inThe respectively light intensity of the outgoing of alkali metal air chamber and incident laser.

5. the method for a kind of non-contact type temperature measurement based on pressure broadening according to claim 1, it is characterised in that： Lorentzian in the step (2) is：

$L\left(\mathrm{\υ}\right)=k\frac{\mathrm{\Γ}/2}{{(\mathrm{\υ}-{\mathrm{\υ}}_0-\mathrm{\δ})}^2+{(\mathrm{\Γ}/2)}^2}$

Wherein, k is proportionality coefficient, and υ is laser frequency, υ₀Centered on frequency, Γ is for spectral line pressure broadening, i.e. Lorentz curve Full width at half maximum, δ is frequency displacement.