Measurement device, and measurement method

Abstract

To make it possible to measure a volatile component with higher accuracy.SOLUTION: A measurement device 1 comprises: a vaporization chamber 21 where a sample S containing an object component is loaded; a measurement chamber 23 that is spatially connected to the vaporization chamber 21, and forms a sealed space integrally with the vaporization chamber 21; a light source 31 that irradiates the measurement chamber 23 with laser light R of which a wavelength changes; a detection unit 51 that detects the laser light R irradiated from the light source 31, and passing through the measurement chamber 23; and a computation unit 60 that analyzes a light reception signal of the laser light R the detection unit 51 detects, and calculates an amount of the object component included in the sample S. The computation unit 60 is configured to acquire an amount of the object component on the basis of an integrated amount of an absorbance spectrum of the laser light R absorbed by the object component during a period of the laser light R passing through the inside of the measurement chamber 23.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a measurement device and a measurement method. [Background technology]

[0002] With the advancement of space development technology, a technique for measuring the content or concentration of water and other volatile components present in samples such as lunar regolith is known. For example, it is known that regolith is collected on the lunar surface, heated to vaporize the components to be measured, and the vaporized components are measured to measure water and other volatile components (Non-Patent Document 1). Note that the lunar surface can be in an extremely low temperature state, and water in regolith often exists as a solid (ice). Water that exists as a solid in an extremely low temperature state can sublimate in response to heating. Therefore, in this document, "vaporization" includes both the process of sublimation, which changes from a solid to a gas, and evaporation, which changes from a liquid to a gas. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Takuma Shimomura and 12 others, "Lunar Polar Region Explorer Project: Development Status of Water Resource Analyzer," Proceedings of the 66th Space Science and Technology Joint Conference, Japan Society for Aeronautical and Space Sciences, 2022. Summary of the Invention [Problem to be solved by the invention]

[0004] However, there was room for improvement in the measurement accuracy of conventional volatile component measurement techniques.

[0005] An object of the present disclosure is to enable measurement of volatile components with higher accuracy. [Means for solving the problem]

[0006] In some embodiments, the measurement device includes: (1) a vaporization chamber in which a sample containing a target component is placed; a measurement chamber spatially connected to the vaporization chamber and integrally forming a sealed space with the vaporization chamber; a light source that irradiates the measurement chamber with a laser beam having a variable wavelength; a detection unit that detects the laser light that is irradiated from the light source and passes through the measurement chamber; a calculation unit that analyzes the light receiving signal of the laser light detected by the detection unit and calculates the amount of the target component contained in the sample; Equipped with The calculation unit is The amount of the target component is obtained based on the integral value of the spectrum of the absorbance of the laser light absorbed by the target component while the laser light passes through the inside of the measurement chamber.

[0007] In this way, the measuring device obtains the amount of the target component based on the integral value of the absorbance spectrum calculated from the intensity of the laser light absorbed by the target component while the laser light passes through the inside of the measurement chamber, so that the amount of the target component can be measured with high accuracy even if the pressure in the enclosed space fluctuates greatly.

[0008] In one embodiment, (2) In the measuring device of (1), The calculation unit may acquire curve data by performing curve fitting to a model equation for the spectrum of absorbance of the laser light, and acquire an integral value of the spectrum based on the curve data.

[0009] In this way, the measurement device performs curve fitting to a model equation for the laser light absorbance spectrum to obtain the integral value (area) of the spectrum, thereby enabling the absorbance spectrum of the target component to be measured with higher accuracy.

[0010] In one embodiment, (3) In the measuring device of (1) or (2), The light source may be a tunable semiconductor laser capable of changing the wavelength of the laser light to be output.

[0011] In this way, by using a tunable semiconductor laser as a light source, the measurement device can sweep the wavelength in a range that includes the central wavelength of the absorption line of the target component and measure the amount of the target component based on the integrated value of the spectrum.

[0012] In one embodiment, (4) In any of the measuring devices described in (1) to (3), the light source irradiates light having a periodically changing wavelength as the laser light, The calculation unit may acquire the spectrum for each of a plurality of periods in which the wavelength of the laser light changes, and acquire the amount of the target component based on the plurality of spectra.

[0013] In this way, the measuring device acquires a spectrum for each of multiple periods in which the wavelength of the laser light changes, and acquires the amount of the target component based on the multiple spectra, thereby reducing the effects of variation in the data for each period and enabling the amount of the target component to be measured with even greater accuracy.

[0014] In one embodiment, (5) In any one of the measuring devices (1) to (4), Further comprising a heater for controlling the temperature of the sample; The calculation unit may output relationship data indicating a correspondence relationship between a temperature of the sample and an amount of the target component calculated by analyzing a received light signal of the laser light.

[0015] In this way, the measuring device outputs relationship data that indicates the correspondence between the temperature of the sample and the amount of the target component, making it possible to analyze the binding state of the target component in the sample based on the relationship data.

[0016] The measurement method according to some embodiments includes: (6) irradiating a measurement chamber, which is spatially connected to a vaporization chamber in which a sample containing a target component is placed and which forms an enclosed space together with the vaporization chamber, with a laser light whose wavelength is changed by a light source; detecting the laser light irradiated from the light source and passing through the measurement chamber by a detection unit; a step of analyzing a light receiving signal of the laser light detected by the detection unit and calculating an amount of the target component contained in the sample by a calculation unit; Including, The calculation unit obtains the amount of the target component based on an integral value of the spectrum of absorbance of the laser light absorbed by the target component while the laser light passes through the inside of the measurement chamber.

[0017] In this way, the measuring device obtains the amount of the target component based on the integral value of the absorbance spectrum calculated from the intensity of the laser light absorbed by the target component while the laser light passes through the inside of the measurement chamber, so that the amount of the target component can be measured with high accuracy even if the pressure in the enclosed space fluctuates greatly.

[0018] In one embodiment, (7) In the measurement method of (6), The calculation unit may acquire curve data by performing curve fitting to a model equation for the spectrum of absorbance of the laser light, and acquire an integral value of the spectrum based on the curve data.

[0019] In this way, the measurement device performs curve fitting to a model equation for the laser light absorbance spectrum to obtain the integral value (area) of the spectrum, thereby enabling the absorbance spectrum of the target component to be measured with higher accuracy.

[0020] In one embodiment, (8) In the measurement method of (6) or (7), The light source may be a tunable semiconductor laser capable of changing the wavelength of the laser light to be output.

[0021] In this way, by using a tunable semiconductor laser as a light source, the measurement device can sweep the wavelength in a range that includes the central wavelength of the absorption line of the target component and measure the amount of the target component based on the integrated value of the spectrum.

[0022] In one embodiment, (9) In any of the measurement methods (6) to (8), the light source irradiates light having a periodically changing wavelength as the laser light, The calculation unit may acquire the spectrum for each of a plurality of periods in which the wavelength of the laser light changes, and acquire the amount of the target component based on the plurality of spectra.

[0023] In this way, the measuring device acquires a spectrum for each of multiple periods in which the wavelength of the laser light changes, and acquires the amount of the target component based on the multiple spectra, thereby reducing the effects of variation in the data for each period and enabling the amount of the target component to be measured with even greater accuracy.

[0024] In one embodiment, (10) In any of the measurement methods (6) to (9), Further comprising a heater for controlling the temperature of the sample; The calculation unit may output relationship data indicating a correspondence relationship between a temperature of the sample and an amount of the target component calculated by analyzing a received light signal of the laser light.

[0025] In this way, the measurement device outputs relationship data that indicates the correspondence between the temperature of the sample and the amount of the target component, making it possible to analyze the binding state of the target component in the sample based on the relationship data. Effect of the Invention

[0026] According to one embodiment of the present disclosure, volatile components can be measured with higher accuracy. [Brief description of the drawings]

[0027] [Figure 1] FIG. 13 is a diagram showing a configuration of a measurement device according to a comparative example. [Diagram 2] FIG. 13 is a diagram showing an example of a graph showing the relationship between the moisture concentration and the internal pressure when the only gas component is water. [Diagram 3] FIG. 1 is a diagram showing an example of a graph illustrating pressure changes in the spectrum of absorbance of water vapor; [Figure 4] FIG. 4 is an enlarged view of a portion of the graph in FIG. [Diagram 5] FIG. 13 is a diagram showing an example of a graph illustrating the relationship between the height of the absorbance spectrum and the moisture content. [Figure 6] FIG. 1 is a diagram illustrating an example of the configuration of a measurement device according to an embodiment. [Figure 7] 7 is a flowchart showing an example of the operation of the measurement device in FIG. 6. [Figure 8] FIG. 4 is a diagram showing a schematic diagram of a change in a laser drive current over time. [Figure 9] FIG. 2 is a diagram illustrating a graph showing the relationship between the driving current and the wavelength of a laser. [Figure 10] FIG. 4 is a diagram showing a schematic change over time in intensity of a received light signal in a detection unit. [Figure 11] FIG. 4 is a diagram illustrating a relationship between a laser wavelength and the intensity of a received light signal. [Figure 12] FIG. 10 is a diagram illustrating a relationship between a laser wavelength and the intensity of a received light signal subjected to baseline processing. [Figure 13] FIG. 2 is a diagram illustrating a relationship between laser wavelength and absorbance. [Figure 14] FIG. 1 is a diagram illustrating a relationship between the height and area of ​​an absorbance spectrum and the amount of a target component. [Figure 15] FIG. 11 is a diagram showing an example of relationship data indicating the relationship between temperature and the amount of a target component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] <Comparative Example> FIG. 1 is a diagram showing the configuration of a measuring device 9 according to a comparative example. The measuring device 9 is a device that measures the amount of a target component, such as water, contained in a sample of a solid material, such as regolith. The measuring device 9 seals the sample in a sealed space and heats the sample to vaporize the target component contained in the sample. The measuring device 9 irradiates the volatile gas with laser light having a single wavelength selected to match the wavelength absorbed by the target component. The measuring device 9 measures the absorbance of the volatile gas and measures the amount of the target component based on the level (value) of the absorbance.

[0029] The measuring device 9 includes a light source 91, a detector 92, and a measuring chamber 93. The measuring chamber 93 provides a sealed space in which gas 94 containing a target component vaporized from a sample is present. The light source 91 irradiates the measuring chamber 93 with laser light (incident light). The detector 92 detects the laser light (transmitted light) that is irradiated from the light source 91 and passes through the measuring chamber 93. The measuring device 9 is assumed to be used in an environment where there is no atmosphere, such as the surface of the moon. Inside the measuring chamber 93, there are no gas components other than the gas 94 vaporized from the sample.

[0030] In the configuration shown in FIG. 1, the measurement device 9 introduces a sample such as regolith to be measured into the measurement chamber 93, and then heats the sample to vaporize the target component from the sample after making the measurement chamber 93 an enclosed space. An example in which the target component is water will be described below. In a state in which gas vaporized from the target component is present, the light source 91 outputs laser light having a specific single wavelength that is known to be absorbed by the target component. The measurement device 9 measures the intensity I0 of the laser light output from the light source 91 and the intensity I of the laser light that has passed through the measurement chamber 93 detected by the detector 92. t The ratio of absorbance H to I is calculated as follows: t ), where ln is the logarithm function with the natural logarithm base e.

[0031] In such a case, it is known that the concentration C of the target component gas is proportional to the absorbance H and inversely proportional to the optical path length L (Beer-Lambert law). The optical path length L is the length that the laser light passes through the space in the measurement chamber 93 where the gas 94 exists. The Beer-Lambert law is expressed by the following equation 1, where ε is the absorption coefficient specific to the molecule of the target component.

[0032] (Formula 1) C=H / εL =ln(I0 / I t ) / εL

[0033] Therefore, by measuring the optical path length L in advance as an apparatus, and by introducing a gas of a known concentration of the target component and measuring the correspondence between the measured absorbance value and the concentration to obtain the absorption coefficient ε in advance, the measuring apparatus 9 can measure the gas concentration from the measured absorbance. If the mass of the sample such as regolith introduced here is known, the measuring apparatus 9 can calculate the water concentration in the regolith.

[0034] However, as the concentration of the target component increases, the pressure in the measurement chamber 93 increases, and the absorbance and the concentration are no longer accurately proportional to each other. Therefore, such an increase in pressure can be a factor in causing errors in the measurement value of the target component. The effect of the pressure in the measurement chamber 93 will be described with reference to Figs. 2 to 5.

[0035] FIG. 2 is a diagram showing an example of a graph showing the relationship between water concentration and internal pressure when it is assumed that the only volatile component is water. In FIG. 2, the horizontal axis is the concentration of the target component, such as water, in the measurement chamber 93. The vertical axis is the pressure in the measurement chamber 93. Graph 901 shows that when the target component evaporates in the measurement chamber 93, which is an enclosed space, the internal pressure increases in proportion to the amount of evaporation. Consider a case where the amount of water in regolith on the actual lunar surface is measured. For example, consider a case where 0.1 g of regolith is sampled and the amount of water is measured by this method in a concentration range of 0.01 wt% to 10 wt%. In such a case, for example, at a temperature of 50°C and an internal volume of 150 cm 3When water, which is a target component, is vaporized in measurement chamber 93, which is an enclosed space, the pressure in measurement chamber 93 changes within a range of approximately 0.01 kPa to 10 kPa.

[0036] FIG. 3 is a diagram showing an example of a graph showing pressure changes in the absorbance spectrum of water vapor. FIG. 4 is a diagram showing an enlarged view of a portion of the graph of FIG. 3. In FIG. 3 and FIG. 4, the horizontal axis indicates the wavelength of the laser light irradiated from the light source 91. The vertical axis indicates the absorbance of light absorbed by the target component in the measurement chamber 93. Graph 911 shows the absorbance spectrum of water vapor at 0.001 kPa. Graph 912 shows the spectrum of water vapor at 0.01 kPa. Graph 913 shows the spectrum of water vapor at 0.1 kPa. Graph 914 shows the spectrum of water vapor at 1 kPa. Graph 915 shows the spectrum of water vapor at 10 Pa. In general, the spectrum of a target component such as water vapor in the near infrared-infrared region is generated by the interaction between light and molecules based on molecular vibration absorption. As shown in graphs 911-915, the line shape of the spectrum is expressed by a Voigt function, which is a convolution of a Gaussian distribution function, which is the broadening due to the Doppler effect, and a Lorentz distribution function, which is the broadening due to molecular collisions. Graphs 911-915 show the spectrum of water vapor at a specified wavelength at a pressure range of 0.00-10 kPa at 100% concentration, every other digit. Graphs 911-915 are based on data from the HITRAN database (https: / / hitran.org / ).

[0037] The shape of the absorbance spectrum is not similar to the pressure but deforms. As a result, the height of the peak of the spectrum changes nonlinearly with respect to the amount of water in the regolith. FIG. 5 is a diagram showing an example of a graph showing the relationship between the height of the absorbance spectrum and the amount of water. In FIG. 5, the horizontal axis indicates the amount of the target component in the measurement chamber 93. Here, the amount of the target component is proportional to the concentration of the target component. The vertical axis indicates the height of the peak of the spectrum. In FIG. 5, the graph 921 has an upwardly convex curved shape. In this way, the height of the spectrum changes nonlinearly with respect to the amount of water in the regolith. Therefore, if the amount of the target component is measured as a value proportional to the height of the spectrum, the measured value of the amount will contain an error. In other words, to accurately measure the amount of the target component based on the height of the spectrum, i.e., the measured value of the absorbance for a laser light of a certain single wavelength, pressure correction using a complex correction curve is required.

[0038] As described above, when trying to measure the content of the heated and vaporized target component over a wide range based on the height of the peak in the absorbance spectrum, the pressure in the closed space increases due to the gas components in the closed space, and the pressure changes over a wide range depending on the amount of the target component. As a result, there is room for improvement in the measurement accuracy of the measuring device 9 according to the comparative example.

[0039] <Embodiment> Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, parts having the same configuration or function are denoted by the same reference numerals. In the description of this embodiment, duplicated descriptions of the same parts may be omitted or simplified as appropriate.

[0040] The present disclosure aims to accurately measure the content of each target component using the absorbance spectrum data of the measurement gas even under a wide range of pressure environments caused by the target components volatilized by heating and increasing the temperature of the sample in an enclosed space. Furthermore, the present disclosure aims to utilize this accurate measurement capability under a wide range of concentrations and pressures to slowly increase the heating temperature at a predetermined rate and obtain relationship data between temperature and the amount of the target component. This relationship data has a shape corresponding to the binding state of the target component to the sample, and can be used to analyze the presence state of the target component in the sample.

[0041] 6 is a diagram showing an example of the configuration of a measurement device 1 according to an embodiment. The measurement device 1 measures the amount of a target component, such as water, contained in a sample S, such as regolith, based on Tunable Diode Laser Absorption Spectroscopy (TDLAS). Below, an example will be described in which the measurement device 1 measures the amount of water (including ice) contained in sandy regolith in an ultra-high vacuum environment, such as the surface of the moon. In such an environment, when the sample S is introduced into a sealed space, it is possible to create a sealed space in an ultra-high vacuum state free of gas components by isolating it from the outside after introduction.

[0042] 6, the measurement device 1 includes an inlet 11, a vaporization chamber 21, a conduit 22, a measurement chamber 23, a light-emitting unit 33, a light-receiving unit 52, and a calculation unit 60. The measurement device 1 includes a window 41 between the light-emitting unit 33 and the measurement chamber 23. The measurement device 1 includes a window 42 between the measurement chamber 23 and the light-receiving unit 52.

[0043] The inlet 11 is an entrance for introducing a sample S such as regolith into the inside of the measurement device 1. The inlet 11 is spatially connected to the vaporization chamber 21. A user can introduce the sample S into the vaporization chamber 21 from the inlet 11. The inlet 11 is provided with a valve 12 for blocking the space from the outside. After the sample S is introduced, the valve 12 is closed to seal the series of spaces consisting of the vaporization chamber 21, the conduit 22, and the measurement chamber 23.

[0044] The vaporization chamber 21 accommodates the sample S. The vaporization chamber 21 includes a heater 24. The heater 24 heats the sample S to control the temperature, and vaporizes a target component contained in the sample S.

[0045] The conduit 22 spatially connects the vaporization chamber 21 and the measurement chamber 23. The target component vaporized in the vaporization chamber 21 spreads through the conduit 22 in a sealed space formed by the vaporization chamber 21, the conduit 22, and the measurement chamber 23.

[0046] The measurement chamber 23 is a space where the vaporized target component is irradiated with laser light R and the absorbance is measured.

[0047] The light-emitting unit 33 outputs laser light R to the measurement chamber 23. The light-emitting unit 33 includes a light source 31 and an optical system 32. The light source 31 is a source of the laser light R. The light source 31 may be, for example, a tunable semiconductor laser capable of changing the wavelength of the laser light R. The optical system 32 includes optical elements such as lenses.

[0048] The laser light R output from the light emitter 33 passes through the measurement chamber 23 via the window 41, and is partially absorbed by the target component. The laser light R that has passed through the measurement chamber 23 reaches the light receiver 52 via the window 42.

[0049] The light receiving unit 52 includes a detection unit 51. When the detection unit 51 detects the laser light R, it outputs an electrical signal according to the light intensity of the laser light R to the calculation unit 60 as a light receiving signal. The detection unit 51 may be, for example, a photodiode having a photoelectric conversion function. The detection unit 51 is electrically connected to the calculation unit 60.

[0050] The calculation unit 60 analyzes the light receiving signal received from the light receiving unit 52 and calculates the amount of the target component contained in the sample S. The calculation unit 60 includes a control unit 61, a storage unit 62, and an input / output unit 63. The control unit 61 includes one or more processors and controls the operation of the calculation unit 60. The storage unit 62 stores data including measurement data and programs. The storage unit 62 may include, for example, a random access memory (RAM), a read only memory (ROM), and storage (for example, a solid state drive (SSD), a magnetic hard disk, etc.). The input / output unit 63 receives operation input from a user and displays the calculation results of the calculation unit 60 to the user. The input / output unit 63 may include an input device and a display device. For example, the input / output unit 63 may include a keyboard, a pointing device, a touch panel, etc. as an input device. The input / output unit 63 may include a liquid crystal panel, an organic electro-luminescence (EL) display, etc. as an output device.

[0051] In the above configuration, the measuring device 1 acquires the amount of the target component based on the integral value of absorbance calculated from the intensity of the laser light R absorbed by the target component while the laser light R passes through the inside of the measurement chamber 23. Specifically, the measuring device 1 analyzes the received light signal to acquire the spectrum of absorbance of the laser light R absorbed by the target component while the laser light R passes through the inside of the measurement chamber 23, and acquires the amount of the target component based on the integral value of the absorbance spectrum. Therefore, according to the measuring device 1, it is possible to measure the amount of the target component with high accuracy even if the pressure in the measurement chamber 23 changes significantly due to vaporization of the target component in an enclosed space.

[0052] FIG. 7 is a flowchart showing an example of the operation of the measuring device 1 in FIG. 6. The operation of the measuring device 1 described with reference to FIG. 7 may correspond to one of the measuring methods of the measuring device 1. As a prerequisite for carrying out the following operations, the measuring device 1 is installed in an ultra-high vacuum state (ultra-low pressure state) similar to the lunar surface at a low temperature level at which ice does not evaporate. In the initial state, the valve 12 of the measuring device 1 is open. The heater 24 is in an OFF state. The vaporization chamber 21 is open to the outside and the heater is also in an OFF state, so that the temperature is low enough that ice does not evaporate, and the state is the same as the ultra-high vacuum state (ultra-low pressure state) on the lunar surface. The following operations are started before the sample S is introduced into the vaporization chamber 21.

[0053] In step S1, the measurement device 1 starts outputting laser light R from the light source 31 and receiving the light at the detection unit 51. In this embodiment, the measurement device 1 operates before the sample S is introduced into the vaporization chamber 21, and starts measuring the absorbance spectrum of moisture, which is a target component.

[0054] In step S2, the measurement device 1 accepts the introduction of the sample S by the user. Specifically, the user introduces the sample S, such as regolith, into the vaporization chamber 21 from the inlet 11, and closes the valve 12 to seal the space consisting of the vaporization chamber 21, the conduit 22, and the measurement chamber 23.

[0055] In step S3, the measuring device 1 heats the sample S with the heater 24 and controls the temperature of the sample S to a desired value. As a result, the water, which is the target component inside the sample S, vaporizes, and the ice also vaporizes. The water diffuses into the measuring chamber 23 through the conduit 22. Since the vaporization chamber 21, the conduit 22, and the measuring chamber 23 form an enclosed space, the concentration of the target component in the measuring chamber 23 increases in accordance with the vaporization of the target component, within a range not exceeding the saturated vapor pressure. During this process, the measuring device 1 continues to measure the absorbance spectrum of the target component by the light emitter 33 and the light receiver 52.

[0056] In step S4, the measurement device 1 acquires a light receiving signal of the laser light R that has passed through the space containing the target component in the measurement chamber 23. Specifically, the detection unit 51 outputs a signal indicating the intensity of the detected laser light R to the calculation unit 60 as a light receiving signal.

[0057] In step S5, the measurement device 1 acquires the amount of the target component based on the area value (integral value) of the absorbance spectrum calculated from the intensity of the laser light R absorbed by the target component. The process of acquiring the amount of the target component will be described in detail later.

[0058] In step S6, the measuring device 1 outputs the amount of the target component acquired in step S5. Specifically, the measuring device 1 stores the measured value of the amount of the target component in the memory unit 62 and displays it on the input / output unit 63. When the process of step S6 is completed, the measuring device 1 ends the process of the flowchart. After such an operation, the measuring device 1 stops heating by the heater 24 and cools down. The user opens the valve 12 to discharge the sample S and open the sealed space in the measuring device 1 to the outside. As a result, the vaporization chamber 21 and the measuring chamber 23 quickly return to an ultra-high vacuum state. If there is another sample S to be measured, the user can measure the target component contained in that sample S.

[0059] Next, details of the process of acquiring the amount of the target component in step S5 will be described with reference to FIGS.

[0060] Fig. 8 is a diagram showing a schematic diagram of a change in the laser drive current over time. In Fig. 8, the horizontal axis indicates time. The vertical axis indicates the magnitude of the laser drive current that drives the light source 31. Graph 781 shows the temporal fluctuation of the laser drive current. In the example of Fig. 8, graph 781 shows that the drive current fluctuates between i0 and i2 at a period t0.

[0061] FIG. 9 is a diagram showing a graph showing the relationship between the laser drive current and the wavelength. In FIG. 9, the horizontal axis shows the magnitude of the laser drive current for driving the light source 31. The vertical axis shows the wavelength of the laser light R output from the light source 31. Graph 801 shows the relationship between the laser drive current and the wavelength when the temperature T of the light source 31 is 20 degrees. Graph 802 shows the relationship between the laser drive current and the wavelength when the temperature T of the light source 31 is 25 degrees. Graph 803 shows the relationship between the laser drive current and the wavelength when the temperature T of the light source 31 is 30 degrees. As shown in the graphs 801 to 803, at a constant temperature, the magnitude of the laser drive current and the wavelength are linearly related to each other. And, at a constant laser drive current, the wavelength of the laser light R tends to increase with increasing temperature. Therefore, the measuring device 1 controls in advance the wavelength of the laser light R output from the light source 31 to be the central wavelength λ1 of the absorption line of a specific wavelength of the water vapor of the target component. Specifically, as shown in Fig. 9, the oscillation wavelength of a semiconductor laser shifts with temperature. Therefore, the measurement device 1 controls the temperature of the light source 31 to a temperature corresponding to the central wavelength λ1 of the absorption line. In the example of Fig. 9, when the laser drive current varies between i0 and i2, the wavelength of the laser light R output from the light source 31 at a temperature T of 25 degrees varies in the range from λ0 to λ2, which includes the central wavelength λ1 of the absorption line of the target component.

[0062] As shown in graph 781 of Fig. 8, the laser drive current changes periodically with a period t0, and as shown in Fig. 9, there is a linear relationship between the magnitude of the laser drive current and the wavelength of the laser light R. Therefore, when the laser drive current changes as shown in graph 781 of Fig. 8, the wavelength of the laser light R also changes periodically. In other words, the light source 31 outputs laser light R whose wavelength has been swept in a range including the central wavelength λ1 of the absorption line of light absorbed by the target component.

[0063] FIG. 10 is a diagram showing a schematic change in the intensity of the light receiving signal in the detection unit 51 over time. In FIG. 10, the horizontal axis indicates time. The vertical axis indicates the intensity of the light receiving signal. In FIG. 10, a graph 782 shows that the intensity of the light receiving signal fluctuates in the range from I0 to I2 at a period t0. Comparing the shape of the graph 782 with that of the graph 781 in FIG. 8, the graph 782 has a shape in which the intensity of the light receiving signal does not increase linearly and has a depression 783 in a part. The depression 783 shows that the laser light R is absorbed by the target component at the absorption wavelength of the target component while the laser light R is passing through the measurement chamber 23. As will be described later, in this embodiment, the measurement device 1 converts the intensity of the light receiving signal into absorbance and calculates the area (integral value) of the spectrum of the absorbance to obtain the amount of the target component.

[0064] The calculation of the area of ​​the portion corresponding to the depression 783 will be described with reference to Figs. 11 to 13. Fig. 11 is a diagram showing a schematic relationship between the laser wavelength and the intensity of the received light signal. In Fig. 11, the horizontal axis indicates the wavelength of the laser light R. The vertical axis indicates the intensity of the received light signal detected by the detection unit 51. Graph 811 shows the relationship between the wavelength of the laser light R and the intensity of the received light signal in a certain period of the periodically varying laser light R. As described above, the wavelength of the laser light R is proportional to the laser drive current (Fig. 9), and in a certain period, the laser drive current has a linear relationship with time as shown in Fig. 8. Therefore, the wavelength in Fig. 11 is a value that corresponds linearly to the time in a certain period of the sweep wavelength. In the example of Fig. 11, graph 811 has a depression near the absorption line central wavelength λ1. The area of ​​the depression corresponds to the area of ​​the depression 783 in Fig. 10. Therefore, the measurement device 1 obtains an area 813 surrounded by an asymptote 812 of the graph 811 and the graph 811, converts it into absorbance, and calculates the area of ​​the portion corresponding to the area 813. Specifically, the measurement device 1 first calculates the difference in the intensity of the received light signal between the asymptote 812 and the graph 811 for each wavelength in the wavelength range from λ0 to λ1, and performs baseline processing of the received light signal.

[0065] 12 is a diagram showing a schematic relationship between the laser wavelength and the intensity of the received light signal that has been subjected to baseline processing. In FIG. 12, the horizontal axis indicates the wavelength of the laser light R. The vertical axis indicates the intensity of the received light signal detected by the detection unit 51. Graph 821 shows a curve obtained by subjecting graph 811 in FIG. 11 to baseline processing. Asymptote (baseline signal) 822 shows a curve obtained by subjecting asymptote 812 in FIG. 11 to baseline processing. Region 823 corresponds to region 813 in FIG. 11.

[0066] Fig. 13 is a diagram showing a schematic relationship between laser wavelength and absorbance. In Fig. 13, the horizontal axis indicates the wavelength of the laser light R, and the vertical axis indicates the absorbance of the laser light R. Graph 831 is obtained by converting graph 821 of Fig. 12 into absorbance. That is, the measurement device 1 calculates a relationship between the intensity I0 of the laser light R output from the light source 31 and the intensity I t The ratio of absorbance H to I is calculated as follows: t ) to get the

[0067] Graph 831 has a shape indicated by the Voigt function described above. It is known that the area A of region 841 enclosed by graph 831 and the horizontal axis is proportional to the concentration C of the target component, the optical path length L of the laser, and the pressure P. Here, the area A corresponds to a value obtained by integrating the absorbance spectrum indicated by graph 831 by wavelength. The pressure P is the pressure in the sealed space due to the generation of all volatile gases including the target component. In other words, assuming that the proportionality coefficient is k, the concentration C of the target component is calculated based on the area A, the optical path length L of the laser, and the pressure P by the following formula 2.

[0068] (Formula 2) C = k × A / (L × P)

[0069] If the volume of the sealed space consisting of the vaporization chamber 21, the conduit 22, and the measurement chamber 23 is V, the molar substance amount M of the target component in the sealed space is calculated by the following formula 3.

[0070] (Formula 3) M = C × P × V = (k × A × V) / L

[0071] Therefore, for a target component with a known amount of substance M, the proportionality coefficient k can be calculated in advance by calculating the area A under conditions of known laser optical path length L and volume V. The measuring device 1 stores such proportionality coefficient k, volume V, and optical path length L in advance in the storage unit 62. When the measuring device 1 calculates the area A of the spectrum of the absorbance of the laser light R, it can obtain the total amount (amount of substance) of the target component that has volatilized from the sample S based on Equation 3.

[0072] FIG. 14 is a diagram showing the relationship between the height and area of ​​the absorbance spectrum of water (gas) at a certain wavelength and the amount of the target component (water in this example) in an enclosed space, calculated using the HITRAN database. In FIG. 14, the horizontal axis indicates the amount of the target component. The vertical axis indicates the height or area of ​​the absorbance spectrum. Graph 851 shows the relationship between the area of ​​the absorbance spectrum and the amount of the target component. Graph 921 shows the relationship between the height of the peak of the absorbance spectrum and the amount of the target component. Since FIG. 14 is an enclosed space, the pressure also increases with the increase in the amount of the target component, and in this example, graphs 851 and 921 are shown in the pressure range of 0.001 k to 10 kPa. As shown in graph 921, the spectral peak height changes nonlinearly with the amount of the component in the high pressure range. In contrast, as shown in graph 851, the spectral area (integral value) changes linearly with the amount of the component in the entire pressure range. Therefore, the measurement device 1 can measure the amount of the target component in the sample S with high accuracy based on the spectrum area (integral value) using Equation 3 over a wide range of pressures and amounts of the target component.

[0073] In addition, when measuring water as a target component, even if the main component of the volatile components contained in the sample S is not water, that is, even if the sample S contains other components in greater amounts than water, the area value (integral value) of the water vapor absorbance spectrum maintains linearity with respect to the amount of the target component (amount of water). In other words, even if the target component is a substance other than water and a volatile component other than the target component is present in an enclosed space, it is known that the amount of the target component and the area of ​​the absorbance spectrum are linearly related over a wide pressure range, regardless of the amount of the substance other than the target component. Therefore, even if the sample S contains components other than the target component of interest, the measuring device 1 can measure the amount of the target component with high accuracy.

[0074] The measuring device 1 may obtain the area of ​​the absorbance spectrum (for example, the area of ​​the region 841 in FIG. 13) by integrating the graph 831 in FIG. 13 with respect to wavelength, or may calculate the area by other methods. For example, the measuring device 1 may perform curve fitting to a model formula such as a Voigt function for the graph 831, focusing on the fact that the absorbance spectrum has a shape of a Voigt function, and may obtain the area using data fitted to a complete Voigt function. Furthermore, the measuring device 1 may calculate the area of ​​the spectrum not over the entire wavelength range of the spectrum formation but over a limited part of the region centered on the spectrum peak wavelength, within the range of allowable error. By performing these processes, the measuring device 1 can measure the spectrum of the target component with higher accuracy and more accurately calculate the amount of the target component. Furthermore, the measuring device 1 may calculate the area (integral value) of a part of the spectrum centered on the spectrum peak wavelength, rather than over the entire wavelength range of the absorbance spectrum, within the range of allowable error.

[0075] In addition, the measuring device 1 can be used not only to calculate the amount of the target component contained in the sample S, but also to determine the binding state of the target component contained in the sample S. For example, water may exist in the sample S as free water, as well as bound water, surface-attached water, or internal water. Although these water molecules are the same as molecules, the temperature at which they vaporize differs depending on the binding state. Therefore, the relationship between the temperature of the sample S and the amount of water molecules that have vaporized from the sample S and are present in the sealed space indicates the distribution of the binding state in which the water existed in the sample S. In other words, the binding state of the original solid sample S and the volatile component of the target component can be analyzed based on the relationship data between the temperature and the volatilization amount. Therefore, the measuring device 1 may measure the amount of the target component, which is the vaporized volatile component contained therein, while heating the sample S in the sealed space with the heater 24 and slowly increasing the temperature of the sample S at a constant rate of increase. The measuring device 1 may output relationship data indicating the correspondence between the temperature of the sample S and the amount of the target component calculated by analyzing the received light signal of the laser light R.

[0076] FIG. 15 is a diagram showing an example of relationship data showing the relationship between temperature and the amount of the target component. In FIG. 15, the horizontal axis shows temperature, and the vertical axis shows the amount of the target component. Graph 861 is the relationship data showing the relationship between temperature and the amount of the target component. The user can analyze the bonding state between the original solid sample S and the volatilized target component based on the temperature at which the amount of the target component increases rapidly and the amount of increase, etc.

[0077] The measuring device 1 of this embodiment can also measure with high accuracy the amount of a target component other than water attached to the sample S by irradiating the sample with light of a wavelength that is absorbed by the target component. For example, the measuring device 1 may measure carbon monoxide, carbon dioxide, oxygen, ammonia, and other components contained in the sample S as target components.

[0078] As described above, the measurement device 1 includes the vaporization chamber 21, the measurement chamber 23, the light source 31, the detection unit 51, and the calculation unit 60. The vaporization chamber 21 is placed with the sample S containing the target component. The measurement chamber 23 is spatially connected to the vaporization chamber 21 and forms a sealed space together with the vaporization chamber 21. The light source 31 irradiates the measurement chamber 23 with a laser light R whose wavelength changes. The detection unit 51 detects the laser light R irradiated from the light source 31 and passed through the measurement chamber 23. The calculation unit 60 analyzes the light receiving signal of the laser light R detected by the detection unit 51 to calculate the amount of the target component contained in the sample S. Here, the calculation unit 60 acquires the amount of the target component based on the area value (integral value) of the absorbance spectrum calculated from the laser light R absorbed by the target component while the laser light R passes through the inside of the measurement chamber 23. Therefore, according to the measurement device 1, even if the pressure in the sealed space fluctuates greatly, the amount of the target component can be measured with high accuracy.

[0079] Furthermore, the calculation section 60 may obtain curve data by performing curve fitting on the spectrum of absorbance of the laser light R to a model formula such as a Voigt function, and obtain the area of ​​the spectrum based on the curve data.

[0080] In this way, the measuring device 1 performs curve fitting on the absorbance spectrum of the laser light R to obtain the area of ​​the spectrum, thereby reducing calculation costs and enabling the amount of the target component to be output at high speed.

[0081] Furthermore, the light source 31 may be a tunable semiconductor laser capable of changing the wavelength of the output laser light R. In this way, by using a tunable semiconductor laser as the light source 31, the measurement device 1 can sweep the wavelength in a range including the central wavelength λ1 of the absorption line of the target component and measure the amount of the target component based on the area of ​​the spectrum.

[0082] Furthermore, the light source 31 may irradiate light whose wavelength changes periodically as the laser light R. The calculation unit 60 may obtain a spectrum for each of a plurality of periods in which the wavelength of the laser light R changes, and obtain the amount of the target component based on the plurality of spectra. In this manner, the measurement device 1 obtains a spectrum for each of a plurality of periods in which the wavelength of the laser light R changes, and obtains the amount of the target component based on the plurality of spectra, thereby suppressing the influence of variation in data for each period and enabling the amount of the target component to be measured with even higher accuracy.

[0083] The measurement device 1 may further include a heater 24 for controlling the temperature of the sample S. The calculation unit 60 may output relationship data indicating the correspondence between the temperature of the sample S and the amount of the target component calculated by analyzing the received light signal of the laser light R. In this way, the measurement device 1 outputs relationship data indicating the correspondence between the temperature of the sample S and the amount of the target component, and therefore it is possible to analyze the binding state of the target component in the sample S based on the relationship data.

[0084] The present disclosure is not limited to the above-described embodiments. For example, multiple blocks shown in the block diagram may be integrated, or one block may be divided. Multiple steps shown in the flowchart may be executed in parallel or in a different order depending on the processing capacity of the device executing each step, or as necessary, instead of being executed in chronological order as described. Other modifications are possible without departing from the spirit of the present disclosure. [Explanation of symbols]

[0085] 1. Measuring equipment 11 Introduction 12 Valves 21 Vaporization chamber 22 Conduit 23 Measurement room 24 Heater 31 Light source 32 Lens 33 Light-emitting part 41, 42 Windows 51 Detection unit 52 Light receiving part 60 Arithmetic section 61 Control section 62 Storage section 63 Input / output section 781, 782 Graph 783 Depression Graph 801~803 811, 812 Graph 821, 822 Graph 831 Graph 841 area 851 Graph 861 Graph 9. Measuring Equipment 91 Light source 92 Detector 93 Measurement room 94 Gas 901, 911-915, 921 Graph S sample

Claims

1. a vaporization chamber in which a sample containing a target component is placed; a measurement chamber spatially connected to the vaporization chamber and integrally forming a sealed space with the vaporization chamber; a light source that irradiates the measurement chamber with a laser beam having a variable wavelength; a detection unit that detects the laser light that is irradiated from the light source and passes through the measurement chamber; a calculation unit that analyzes the light receiving signal of the laser light detected by the detection unit and calculates the amount of the target component contained in the sample; Equipped with The calculation unit is acquiring an amount of the target component based on an integral value of a spectrum of absorbance of the laser light absorbed by the target component while the laser light passes through the inside of the measurement chamber; Measuring equipment.

2. The measurement device according to claim 1 , wherein the calculation unit obtains curve data by performing curve fitting to a model equation for the spectrum of absorbance of the laser light, and obtains an integral value of the spectrum based on the curve data.

3. 2. The measuring device according to claim 1, wherein the light source is a tunable semiconductor laser capable of changing the wavelength of the laser light that it outputs.

4. the light source irradiates light having a periodically changing wavelength as the laser light, the calculation unit acquires the spectrum for each of a plurality of periods in which the wavelength of the laser light changes, and acquires the amount of the target component based on the plurality of spectra.

2. The measuring device of claim 1.

5. Further comprising a heater for controlling the temperature of the sample; the calculation unit outputs relationship data indicating a correspondence relationship between the temperature of the sample and the amount of the target component calculated by analyzing the light receiving signal of the laser light.

2. The measuring device of claim 1.

6. a step of irradiating a measurement chamber, which is spatially connected to a vaporization chamber in which a sample containing a target component is placed and which forms an enclosed space together with the vaporization chamber, with a laser light whose wavelength is changed by a light source; detecting the laser light irradiated from the light source and passing through the measurement chamber by a detection unit; a step of analyzing a light receiving signal of the laser light detected by the detection unit and calculating an amount of the target component contained in the sample by a calculation unit; Including, the calculation unit acquires the amount of the target component based on an integral value of a spectrum of absorbance of the laser light absorbed by the target component while the laser light passes through an interior of the measurement chamber. Measurement method of the measuring device.

7. The measurement method according to claim 6 , wherein the calculation unit obtains curve data by performing curve fitting to a model equation for the spectrum of absorbance of the laser light, and obtains an integral value of the spectrum based on the curve data.

8. The measurement method according to claim 6 , wherein the light source is a tunable semiconductor laser capable of changing the wavelength of the laser light it outputs.

9. the light source irradiates light having a periodically changing wavelength as the laser light, the calculation unit acquires the spectrum for each of a plurality of periods in which the wavelength of the laser light changes, and acquires the amount of the target component based on the plurality of spectra. The measurement method according to claim 6.

10. Further comprising a heater for controlling the temperature of the sample; the calculation unit outputs relationship data indicating a correspondence relationship between the temperature of the sample and the amount of the target component calculated by analyzing the light receiving signal of the laser light. The measurement method according to claim 6.

Images