CN117491312A - Laser wavelength correction device, gas concentration detection system and method - Google Patents
Laser wavelength correction device, gas concentration detection system and method Download PDFInfo
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Abstract
The present disclosure relates to a laser wavelength correction device, a gas concentration detection system and a method, the laser wavelength correction device comprising: a reference source, a beam receiving device and a beam output device. The light beam output device outputs light beams with adjustable wavelength, the reference source is provided with an inflation inlet, target gas is led into the reference source through the inflation inlet, and the target gas is blocked after the target gas quantity reaches a preset pressure. One end of the reference source is an incident light-transmitting end for receiving the light beam output by the light beam output device, and the other end opposite to the incident light-transmitting end is an emergent light-transmitting end. The light beam receiving device acquires a spectrum signal of a light beam output from an outgoing light transmitting end portion of the reference source, and takes the light beam having the maximum absorption intensity as a target light beam. The device can identify the target light beam with the maximum absorption intensity under the target gas, provides more reliable technical support for the subsequent gas concentration measurement, and has the advantages of small volume and low cost.
Description
Technical Field
The disclosure relates to the technical field of gas detection, in particular to a laser wavelength correction device, a gas concentration detection system and a method.
Background
The cavity ring-down spectroscopy (CRDS) technology is a high-sensitivity absorption spectrum detection technology which is rapidly developed in recent years. Because of its advanced technical advantages, it has become a powerful tool for analyzing various trace or trace substances. There is a need in the art for a semiconductor laser capable of emitting a wavelength.
In practical applications, the semiconductor laser may be affected by factors such as disturbance of a field environment or change of a working state of long-term continuous operation, which may cause drift of an output wavelength of the laser, thereby causing degradation of accuracy of detecting the gas concentration. Therefore, correction of the laser wavelength emitted by the laser is necessary.
The existing laser wavelength measurement technology is an etalon interferometry, but the wavelength measurement method is only suitable for the wavelength locking of a laser with fixed wavelength output, is not suitable for the wavelength correction of the laser output of continuous scanning, and a gas concentration measurement system manufactured by the method has large volume and high cost.
Disclosure of Invention
The disclosure provides a laser wavelength correction device, a gas concentration detection system and a method for solving the problems of large volume and high cost of a gas measurement device in the prior art.
According to a first aspect of the present disclosure, there is provided a laser wavelength correction apparatus comprising:
a light beam output device configured to output a light beam whose wavelength can be adjusted;
a reference source having an inflation port configured to introduce a target gas into the reference source and to be blocked after the target gas volume reaches a preset pressure; and, in addition, the method comprises the steps of,
one end of the reference source is an incident light-transmitting end for receiving the light beam output by the light beam output device, and the other end opposite to the incident light-transmitting end is an emergent light-transmitting end;
and a light beam receiving device configured to acquire a spectrum signal of the light beam output from the outgoing light transmitting end portion of the reference source and take the light beam having the maximum absorption intensity as a target light beam.
In one embodiment of the present disclosure, the inflation port is plugged by a fusion process.
In one embodiment of the present disclosure, the incident light-transmitting end portion and the exit light-transmitting end portion are disposed obliquely with respect to a transmission light path of the light beam within the reference source.
In one embodiment of the present disclosure, the angle of inclination of the incident light-transmitting end portion with respect to the light beam transmission path in the reference source is equal to the angle of inclination of the exit light-transmitting end portion with respect to the light beam transmission path in the reference source, the angle of inclination ranging from 50 ° to 80 °.
In one embodiment of the present disclosure, the reference source comprises:
the incident light-transmitting end part and the emergent light-transmitting end part are arranged on the first sealing tube;
the two opposite ends of the second sealing tube are open, the second sealing tube is vertically communicated with the first sealing tube through one tube orifice, and the air charging port is the other tube orifice of the second sealing tube.
In one embodiment of the present disclosure, the inflation port is located between the incident light transmitting end and the exit light transmitting end.
In one embodiment of the present disclosure, the light beam output device has a wavelength adjusting element configured to adjust an output wavelength of the light beam by changing a temperature or a light beam output device current.
According to a second aspect of the present disclosure, there is also provided a gas concentration measurement system comprising:
the laser wavelength correction device;
an actual measurement device configured to measure a concentration in the target gas based on cavity ring-down spectroscopy using the target beam.
According to a third aspect of the present disclosure, there is also provided a gas concentration measurement method implemented by the aforementioned gas measurement apparatus, the gas concentration measurement method including the steps of:
introducing target gas from an inflation inlet to the reference source until the target gas reaches a preset pressure, and sealing the inflation inlet;
inputting a light beam from an incident light transmitting end to the reference source;
a beam receiving device determines a beam spectrum signal output from the outgoing light transmitting end portion of the reference source, and takes the beam with the maximum absorption intensity as a target beam;
the light beam output device outputs the target light beam to the actual measuring device;
the actual measuring device measures the concentration in the target gas based on the cavity ring-down spectroscopy by using the input target light beam.
In one embodiment of the present disclosure, the reference source is in a vacuum state prior to introducing the target gas from the gas fill port to the reference source.
The laser wavelength correction device has the advantages that the reference source for leading in the target gas with preset pressure is plugged, the light beam output by the light beam output device is emitted from the incident light transmission end part of the reference source and emitted from the emergent light transmission end part of the reference source, then the light beam is received by the light beam receiving device and is used for measuring spectrum signals, and the light beam with the maximum absorption intensity is used as the target light beam by comparing the spectrum signals corresponding to the light beams with different wavelengths. The device can effectively identify the target light beam with the maximum absorption intensity under the target gas, provides more reliable technical support for the subsequent gas concentration measurement, and has the advantages of small volume and low cost.
Other features of the present disclosure and its advantages will become apparent from the following detailed description of exemplary embodiments of the disclosure, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.
FIG. 1 is a block diagram of a laser wavelength correction device provided in an embodiment of the present disclosure;
FIG. 2 is a schematic view of a reference source provided in an embodiment of the present disclosure prior to fusion;
FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;
FIG. 4 is a schematic view of a reference source provided in an embodiment of the present disclosure after fusion;
FIG. 5 is a cross-sectional view taken along the direction B-B of FIG. 4;
FIG. 6 is a schematic view of the angle of a reference source upon beam entry provided by an embodiment of the present disclosure;
FIG. 7 is a block diagram of a gas concentration measurement system provided in an embodiment of the present disclosure;
fig. 8 is a main step of a gas concentration measurement method provided in an embodiment of the present disclosure.
The one-to-one correspondence between the component names and the reference numerals in fig. 1 to 8 is as follows:
1. a reference source; 11. an incident light transmitting end; 12. a light transmitting end part is emergent; 13. an inflation inlet; 14. a first sealing tube; 15. a second sealing tube;
2. a light beam receiving device; 3. a light beam output device; 4. an actual measuring device.
Detailed Description
Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
In this document, "upper", "lower", "front", "rear", "left", "right", and the like are used merely to indicate relative positional relationships between the relevant portions, and do not limit the absolute positions of the relevant portions.
Herein, "first", "second", etc. are used only for distinguishing one another, and do not denote any order or importance, but rather denote a prerequisite of presence.
Herein, "equal," "same," etc. are not strictly mathematical and/or geometric limitations, but also include deviations that may be appreciated by those skilled in the art and allowed by fabrication or use, etc.
In measuring the concentration of the target gas, the wavelength of the beam having the best absorption intensity for the target gas is generally selected as the preset wavelength, and the beam having the preset wavelength is emitted by a beam output device (in some embodiments, the beam output device is integrated with an actual measuring device). However, in the practical application process, due to environmental effects or equipment reasons, the actual wavelength of the light beam output by the practical measurement device may be shifted, which eventually results in distortion of the concentration of the target gas measured by the practical measurement device using the cavity ring-down spectroscopy.
To this end, the present disclosure provides a laser wavelength correction device, a gas concentration detection system and a method. To facilitate understanding, the terminology involved in one or more embodiments of the present disclosure is first explained.
Cavity ring-down spectroscopy: almost every small gas phase molecule (e.g., CO 2 ，H 2 O，H 2 S，NH 3 ) All have unique absorption spectra. At atmospheric pressure, sub-atmospheric pressure, it consists of a series of narrow, well-resolved sharp spectral curves, each having a characteristic wavelength. Because these curves are well spaced and their wavelength is known, the concentration of any substance can be determined by measuring the absorbance at that wavelength, i.e., the height of a particular absorption peak. Cavity ring-down spectroscopy, i.e., by using an effective absorption path up to several kilometers to break through the sensitivity limitations of conventional techniques, can monitor gases in a matter of seconds or less, can reach ppb (parts per billion concentration) levels, and even some gases can reach ppt (parts per trillion concentration) levels.
Lambert beer law: is the basic law of light absorption, describing the relationship between the intensity of absorption of a substance to a certain wavelength of light and the concentration of the light absorbing substance and its liquid layer thickness.
Half width: also referred to as half-width, refers to the full width of the band when the absorption band is half as high as the maximum, i.e., the width of the transmission peak when the peak is half as high. Commonly used to represent energy resolution.
Referring to fig. 1, fig. 1 is a block diagram of a laser wavelength correction device according to an embodiment of the present disclosure, where the laser wavelength correction device includes at least a reference source 1, a beam receiving device 2, and a beam output device 3.
Referring to fig. 2 and 3, in one embodiment, the beam output device of the present disclosure is configured to output a beam of adjustable wavelength, the reference source 1 has an inflation port 13, and the inflation port 13 is configured to introduce a target gas into the reference source 1 and is blocked after the target gas reaches a preset pressure. For better understanding, please refer to fig. 4 and fig. 5 together, wherein fig. 4 is a schematic structural view of the reference source after welding according to an embodiment of the disclosure, and fig. 5 is a cross-sectional view along the direction B-B of fig. 4.
One end of the reference source 1 is an incident light-transmitting end 11 that receives the light beam outputted from the light beam output device 3, and the other end opposite to the incident light-transmitting end 11 is an outgoing light-transmitting end 12.
The light beam receiving device 2 is configured to acquire a light beam spectrum signal output from the outgoing light transmitting end portion 12 of the reference source 1, and take the light beam having the maximum absorption intensity as a target light beam.
The specific working process of the laser wavelength correction device comprises the following steps of;
firstly, inputting target gas to be measured into a reference source through an inflation inlet until the target gas in the reference source reaches a preset pressure, and then sealing the inflation inlet to enable the reference source to be in a sealing state. That is, the reference source is not refilled with gas when the reference source is subsequently utilized to measure the concentration of the target gas;
next, the light beam output device 3 emits a light beam with adjustable wavelength, and the light beam is incident from the reference source incident light transmitting end 11 and is emitted from the emergent light transmitting end 12.
In the process, the target gas within the reference source absorbs a portion of the beam, such that the intensity of the beam emitted from within the reference source varies. The light beam emitted from the reference source 1 is received by the light beam receiving means 2. The light beam receiving means 2 can measure the spectral signal of the emitted light beam.
Since the wavelength of the light beam output by the light beam output device is adjusted, the light beam receiving device 2 can obtain the spectrum signals corresponding to the light beams with different wavelengths, and the light beam with the maximum absorption intensity is taken as the target light beam by comparing the spectrum signals of the light beams with different wavelengths, namely, the light beam which is actually used in the subsequent gas concentration measurement.
The light beam having the highest absorption intensity is used as the target light beam because the gas is measured with the most accurate measurement result by using the light beam having the highest absorption intensity under the gas when the concentration of the gas is measured.
In one embodiment of the present disclosure, the light beam output device 3 has a wavelength adjusting element configured to adjust the output wavelength of the light beam by changing the temperature or the light beam output device 3.
Taking the example of adjusting the output wavelength of the light beam by temperature, in the practical application process, since the process of drifting the wavelength of the light beam is slow, the target light beam needs to be redetermined every 4 hours. Specifically, the light beam output device is controlled by the temperature controller to output light beams of different wavelengths, and by adjusting the temperature range, a light beam having the maximum absorption intensity by the target gas in the reference source in the temperature range can be obtained as a target light beam, that is, a desired light beam. Then, the temperature of the temperature controller of the light beam output device is set to be the temperature corresponding to the light beam, so that the light beam output device can emit a target light beam for subsequent gas concentration measurement.
It should be noted that the above-mentioned light beam may be a laser beam commonly used for gas measurement, such as an infrared laser beam.
In addition, the "target gas" herein refers to a gas whose pressure is to be measured, and the preset pressure value inputted into the target gas of the reference source is set by those skilled in the art based on the actual measurement requirement, so as to calculate the theoretical wavelength of the light beam emitted from the reference source.
Specifically, the light beam receiving device acquires a spectrum signal of a light beam output from an outgoing light transmitting end of a reference source, and the specific principle is as follows:
since the absorption intensity of the light beam by the target gas when passing through the target gas is related to the absorption path length and the concentration of the target gas. Thus, the theoretical intensity of the light beam passing through the reference source can be calculated by the lambert-beer law, which is specifically described as:
wherein, I is 0 (v) Is the incident light intensity of the light beam, and I (v) is the light intensity of the light beam after being absorbed by the target gas; p [ atm ]]Is the pressure of the target gas; s (T) [ cm ] -2 atm -1 ]The line intensity of the characteristic spectral line of the gas represents the spectral line absorption intensity and is only related to temperature; phi (v) is an absorption linear function of the molecules and is related to the concentration, pressure and other parameters of the target gas; x is the molecular concentration; l [ cm ]]Is an effective absorption optical path.
The linear function phi (v) is a function used to describe the line profile. The linear functions can be divided into two linear functions of uniform broadening and nonuniform broadening due to different spectral line broadening mechanisms, including Gauss linear, lorentz linear and the like, and Lorentz linear functions are adopted by analysis and comparison of the present disclosure.
Lorentz widening, also called pressure widening, is a typical uniform widening. The Lorentz function is used to represent the pressure widening line type:
wherein w is L Is the half-height full width of the pressure widening, v represents the spectral line frequency, v 0 Is the spectral line center frequency.
The full width at half maximum of the pressure widening is proportional to the pressure, and the specific formula is as follows:
p represents the gas pressure, x i Is the gas concentration, r i As a pressure widening factor, which is temperature dependent, the specific formula is as follows:
n i is the temperature index, T 0 ＝296K，r i (T 0 ) Is the pressure widening factor at standard temperature.
The gas pressure P and the effective absorption optical path L can be calculated by the following formula:
where A is absorption intensity, sigma represents a loss section constituting an absorption characteristic of the target gas, and is a product of absorption line intensity S (T) and absorption line function phi (v). n is the corresponding number density. Na is Avgalde Luo Changliang, R is a gas constant, and T is a gas temperature.
It should be explained that when light is not absorbed, the absorption intensity a is 0, and when light is all absorbed, the absorption intensity a is 1. Since the scanning spectrum has obvious absorption peaks when the absorption intensity A is in the range of 0.2-0.8, the effective absorption optical path L and the gas pressure P can be calculated through testing in the absorption intensity range.
The absorption linear function phi (v) can be calculated by the above formula, and is brought into lambert-beer law, so that the theoretical light intensity of the light beam passing through the reference source 1 can be obtained.
By comparing the theoretical light intensity with the spectrum signal of the light beam which is not absorbed by the target gas, the absorption intensity of the light beam under the target gas can be obtained. By comparing the absorption intensities of the light beams with different wavelengths, the light beam with the maximum absorption intensity under the target gas can be obtained, namely, the target light beam during the subsequent gas concentration measurement.
The reference source of the present disclosure has a function of storing a target gas as described above with reference to fig. 3 and 5, and also has a function of introducing an externally incident light beam into the reference source from an incident light transmitting end portion, absorbing the light beam by the target gas in the reference source, and finally emitting the light beam from an outgoing light transmitting end portion. That is, the reference source of the present disclosure has at least two opposite ends with a light transmitting function.
In order to simplify the manufacturing cost of the reference source, the reference source of the present disclosure is a glass tube, that is, the whole structure thereof has a light transmitting function.
Of course, in some embodiments, only two opposite ends of the reference source, that is, the incident light-transmitting end and the emergent light-transmitting end, are made of glass, and the rest may be made of opaque materials such as metal, plastic, etc., that is, only the materials of the two ends of the reference source need to be guaranteed to meet the light transmittance requirement.
Further, in order to avoid the influence of temperature variation on the reference source 1, the pressure of the target gas in the reference source 1 is changed. In one embodiment of the present disclosure, the reference source 1 is made of materials with a small thermal expansion coefficient, preferably, a quartz glass tube.
As mentioned above, the reference source is provided with an inflation inlet, which is used for inputting the target gas with preset pressure into the reference source, and blocking the inflation inlet after the target gas in the reference source reaches the preset pressure so as to prevent the target gas in the reference source from leaking.
Based on the fact that the reference source is a quartz glass tube and the like and is supported by transparent glass, after target gas in the reference source reaches preset pressure, an inflation inlet of the reference source can be plugged directly through a welding process, and the reference source is arranged to have high air tightness, leakage of the target gas can be prevented better, and accordingly measuring results can be accurate.
Of course, in other embodiments, after the target gas in the reference source reaches the preset pressure, the inflation inlet of the reference source may be plugged by other components such as a wooden plug.
Referring to fig. 6, in one embodiment of the present disclosure, in order to prevent interference of a light beam due to reflection of the light beam by the incident light-transmitting end 11 or the outgoing light-transmitting end 12 when the light beam passes through the reference source 1, the incident light-transmitting end 11 and the outgoing light-transmitting end 12 of the reference source 1 are disposed obliquely with respect to a transmission light path of the light beam within the reference source 1.
Meanwhile, in order to ensure that the light beam can be emitted along the horizontal direction, the inclined included angle between the incident light-transmitting end 11 and the light beam transmission light path in the reference source 1 needs to be equal to the inclined included angle between the emergent light-transmitting end 12 and the light beam transmission light path in the reference source 1.
Referring to fig. 6, in one embodiment of the present disclosure, the angle of inclination of the incident light-transmitting end 11 with respect to the light beam transmission path in the reference source 1 and the angle of inclination of the exit light-transmitting end 12 with respect to the light beam transmission path in the reference source 1 are set to a range of 50 ° -80 °.
By the arrangement, the light beam can not be disturbed by reflected light when entering the reference source 1, and a sufficient quantity of light beam can pass through the reference source 1 to finish measuring the absorption intensity of the light beam.
In one embodiment of the present disclosure, the reference source 1 has a circular or rectangular cross section in a direction perpendicular to the transmission path of the light beam. The reference source 1 with the cross section in the shape can effectively avoid the interference of the light beam caused by the reflection of the light beam by the inner wall of the reference source 1 in the process that the light beam advances along the transmission light path in the reference source 1. Meanwhile, the structure is simple and easy to manufacture.
In one embodiment of the present disclosure, the reference source 1 comprises a first sealed tube 14 and a second sealed tube 15, the incident light-transmitting end 11 and the exit light-transmitting end 12 being arranged at the first sealed tube 14. The two opposite ends of the second sealing tube 15 are arranged in an open manner, the second sealing tube 15 is vertically communicated with the first sealing tube 14 through one tube orifice, and the air charging opening 13 is the other tube orifice of the second sealing tube 15.
After the target gas of a predetermined pressure is introduced into the reference source 1, only one nozzle of the second sealing tube 15, that is, the inflation inlet 13, is required to be welded and sealed. Therefore, leakage of target gas caused by loose sealing is avoided, and the accuracy of gas concentration measurement is finally affected. For ease of processing, the inflation port 13 is located between the incident light transmitting end 11 and the exit light transmitting end 12.
Meanwhile, in order to ensure that the target gas with preset pressure is introduced into the reference source 1, the target gas composition is not changed, and the wavelength inspection result is affected. Before introducing a target gas at a predetermined pressure into the reference source 1, it is necessary to evacuate the gas inside the reference source 1 to maintain it in a vacuum state.
In one embodiment of the present disclosure, to ensure accuracy of target gas wavelength detection. After the target gas is introduced from the gas charging port 13 to the reference source 1, the inside of the reference source 1 is in a negative pressure state, and the pressure range is 5-26Kpa.
The disclosure also provides a gas concentration measurement system based on cavity ring-down spectroscopy, which comprises the laser wavelength correction device and an actual measurement device, and a structural block diagram of the gas concentration measurement system is shown in fig. 7. The laser wavelength correction device is already discussed in detail above, and will not be described in detail here.
The actual measurement device 4 is configured to measure the concentration in the target gas based on cavity ring-down spectroscopy using the target beam.
It should be noted that, the beam output device 3 determines the target beam most suitable for measuring the concentration of the target gas based on the absorption intensity, the beam output device 3 inputs the target beam into the actual measurement device, and finally the actual measurement device measures the concentration of the target gas by using the target beam to correct the problem of the distortion of the measurement result of the actual measurement device caused by the wavelength shift of the beam due to environmental factors and/or equipment structure, thereby improving the accuracy of the measurement result of the actual measurement device and providing more reliable data support for the subsequent use link of the side face data.
In addition, the gas concentration measurement system disclosed by the invention is only added with a reference source with a simple structure and a light beam receiving device matched with the reference source on the basis of a traditional actual measurement device, so that the correction of the offset wavelength of the light beam injected into the actual measurement device is realized, and the whole system has a simple structure and low cost.
With continued reference to fig. 7, in order to simplify the structure of the whole system during practical application, the light beam output device 3 is integrally arranged in the practical measuring device 4, but in other embodiments, the light beam output device 3 may also be independent of the practical measuring device 4.
Furthermore, to further simplify the structure of the gas concentration measurement system, in one embodiment, the gas concentration measurement system of the present disclosure simultaneously supplies the reference source 1 and the actual measurement device 4 with light beams using the same light beam output device 3.
Specifically, the light beam output device in the actual measurement device 4 firstly emits a light beam with adjustable wavelength, the light beam is separated into two light beams under the action of a light separator or other devices, the two light beams respectively emit to the reference source and the actual measurement device, and the two light beams belong to the light beam with the same wavelength, so that the wavelengths of the two light beams are the same.
Obviously, in the embodiment, the same light beam is split into two light beams with the same wavelength by using the beam splitter and respectively injected into the reference source and the actual measuring device to execute corresponding tasks, so that the structure of the gas concentration measuring system is simplified.
Of course, in other embodiments, the gas concentration measurement system of the present disclosure may be configured with the reference source 1 and the actual measurement device 4 with the beam output device 3 independent of each other.
The light beam receiving device 2 compares the spectrum signals of the light beams with different wavelengths to set the light beam with the maximum absorption intensity as the target light beam, and then the light beam output device 3 inputs the target light beam to the actual measurement device 4, and the actual measurement device 4 measures the concentration in the target gas based on the cavity ring-down spectroscopy by using the input target light beam.
In addition to the above-described gas concentration measurement system based on cavity ring-down spectroscopy, the present disclosure also provides a gas concentration measurement method based on cavity ring-down spectroscopy, which can be implemented by the above-described gas concentration measurement system, so that the gas concentration measurement method of the present disclosure has the technical effects of the system described above. In order to keep the text concise, the steps of the gas concentration measurement method of the present disclosure will be described in conjunction with fig. 8, overlapping and identical parts to those of the previous system, and those skilled in the art will refer to the previous description, and will not be repeated herein,
referring to fig. 8, the method for measuring gas concentration based on optical cavity ring-down spectroscopy provided by the present disclosure includes the following steps:
s200: introducing target gas from the gas charging port 13 to the reference source 1 until the target gas reaches a preset pressure, and then sealing the gas charging port 13;
s400: inputting a light beam from an incident light transmitting end 11 to a reference source 1;
s600: the light beam receiving device 2 determines a light beam spectrum signal output from the outgoing light transmitting end portion of the reference source 1, and takes a light beam with the maximum absorption intensity as a target light beam;
s800: the beam output device 3 outputs a target beam to the actual measurement device 4;
s1000: the actual measurement device 4 measures the concentration in the target gas based on the cavity ring-down spectroscopy using the input target beam.
Further, in order to avoid that the target gas in the reference source is doped with other gases and affects the measurement result, the gas concentration measurement method of the present disclosure further includes the following steps before step S200:
s100: the gas in the reference source 1 needs to be evacuated to enable the reference source 1 to be in a vacuum state, so that the influence of the change of the target gas component to the wavelength inspection result after the target gas is introduced into the reference source 1 is avoided.
Further, in step S200, the pressure range in the reference source is 5-26Kpa after the target gas in the reference source reaches the preset concentration, and the inside of the reference source 1 pipe is in a negative pressure state because the atmospheric pressure is 101 Kpa.
Further, in carrying out the gas concentration measurement method according to the present disclosure, the gas measurement devices of the above-described embodiments may also be used in combination.
Since the reference source 1 is plugged after a certain target gas is introduced, the reference source 1 can be used as a measuring device for the target gas for a long time.
The method for measuring the target gas can reduce cost, save assembly time and improve measurement efficiency.
The foregoing description of the embodiments of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the present disclosure is defined by the appended claims.
Claims (10)
1. A laser wavelength correction device, the laser wavelength correction device comprising:
a light beam output device (3) configured to output a light beam whose wavelength can be adjusted;
-a reference source (1), the reference source (1) having an inflation port (13), the inflation port (13) being configured to introduce a target gas into the reference source (1) and to be blocked after the target gas quantity reaches a preset pressure; and, in addition, the method comprises the steps of,
one end of the reference source (1) is an incident light-transmitting end (11) for receiving the light beam output by the light beam output device (3), and the other end opposite to the incident light-transmitting end (11) is an emergent light-transmitting end (12);
a light beam receiving device (2), the light beam receiving device (2) being configured to acquire a spectrum signal of the light beam output from the outgoing light transmitting end (12) of the reference source (1), and to take the light beam having the maximum absorption intensity as a target light beam.
2. A laser wavelength correction device according to claim 1, characterized in that the gas filling opening (13) is plugged by a welding process.
3. A laser wavelength correction device according to claim 1, characterized in that the entrance light transmitting end (11) and the exit light transmitting end (12) are arranged obliquely with respect to the transmission path of the light beam within the reference source (1).
4. A laser wavelength correction device as claimed in claim 3, characterized in that the angle of inclination of the incident light-transmitting end (11) with respect to the light beam transmission path in the reference source (1) is equal to the angle of inclination of the exit light-transmitting end (12) with respect to the light beam transmission path in the reference source (1), said angle of inclination being in the range of 50 ° -80 °.
5. A laser wavelength correction device according to claim 1, characterized in that the reference source (1) comprises:
a first sealing tube (14), the incident light-transmitting end (11) and the exit light-transmitting end (12) being arranged at the first sealing tube (14);
the two opposite ends of the second sealing tube (15) are open, the second sealing tube (15) is vertically communicated with the first sealing tube (14) through one tube orifice, and the inflation inlet (13) is the other tube orifice of the second sealing tube (15).
6. A laser wavelength correction device according to claim 5, characterized in that the gas filling opening (13) is located between the entrance light transmitting end (11) and the exit light transmitting end (12).
7. A laser wavelength correction device according to claim 1, characterized in that the beam output device (3) has a wavelength adjusting element configured to adjust the output wavelength of the beam by changing the temperature or the current of the beam output device (3).
8. A gas concentration measurement system, the gas concentration measurement system comprising:
the laser wavelength correction apparatus of any one of claims 1-7;
-an actual measurement device (4), the actual measurement device (4) being configured to measure the concentration in the target gas based on cavity ring-down spectroscopy with the target beam.
9. A gas concentration measurement method, characterized in that the gas concentration measurement method is implemented by the gas concentration measurement system according to claim 8, the gas concentration measurement method comprising the steps of:
introducing target gas from an inflation inlet (13) to the reference source (1) until the target gas reaches a preset pressure, and sealing the inflation inlet (13);
inputting a target beam from an incident light-transmitting end (11) to the reference source (1);
a light beam receiving device (2) determines a light beam spectrum signal output from the outgoing light transmitting end (12) of the reference source (1) and takes the light beam with the maximum absorption intensity as a target light beam;
the beam output device (3) outputs the target beam to the actual measuring device (4);
the actual measuring device (4) measures the concentration in the target gas based on cavity ring-down spectroscopy by using the input target light beam.
10. A gas concentration measuring method according to claim 9, characterized in that the reference source (1) is in a vacuum state before the target gas is introduced from the gas filling port (13) to the reference source (1).
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| CN202311445378.8A CN117491312A (en) | 2023-11-01 | 2023-11-01 | Laser wavelength correction device, gas concentration detection system and method |
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| CN202311445378.8A CN117491312A (en) | 2023-11-01 | 2023-11-01 | Laser wavelength correction device, gas concentration detection system and method |
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| CN202311445378.8A Pending CN117491312A (en) | 2023-11-01 | 2023-11-01 | Laser wavelength correction device, gas concentration detection system and method |
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