Absorbance Analysis System, Program Storage Medium, and Absorbance Measurement Method

Abstract

Provided is an absorption analysis system, comprising: a detector that detects the intensity of light that has passed through a gas; a total pressure sensor that measures the total pressure of the gas; an interfering gas partial pressure-absorbance relationship storage unit that stores interfering gas partial pressure-absorbance relationship data; an interfering gas partial pressure estimation unit that estimates the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor; an interfering gas absorbance conversion unit that converts the estimated partial pressure of the interfering gas estimated by the interfering gas partial pressure estimation unit into the absorbance of the interfering gas based on the interfering gas partial pressure-absorbance relationship data; and a measurement target gas absorbance calculation unit that calculates the absorbance of the measurement target gas based on the output value of the detector and the absorbance of the interfering gas converted by the interfering gas absorbance conversion unit.

Description

Technical Field

[0001] The present invention relates to an absorption analysis system, a program storage medium for an absorption analysis system, an absorption analysis device, and an absorbance measurement method. Background Art

[0002] Conventionally, as a system for measuring the concentration of a measurement target gas contained in a gas supplied to a supply target such as a chamber of a film forming apparatus in a semiconductor manufacturing process, there has been an absorption analysis system including a detector that detects the intensity of light transmitted through the gas and a total pressure sensor that measures the total pressure of the gas.

[0003] It should be noted that the above detector has the following structure: including, for example, a light source that irradiates light to the gas flowing in the flow path, a filter that allows light having a wavelength absorbed by the measurement target gas (hereinafter, also referred to as the measurement wavelength) among the wavelengths of the light emitted from the light source to pass through, and a light receiving unit that detects the intensity of the light having the measurement wavelength transmitted through the gas.

[0004] However, sometimes an interfering gas that absorbs light having the measurement wavelength is contained in the gas analyzed by the above-described conventional absorption analysis system as other gas other than the measurement target gas. In this case, not only the intensity of the light having the measurement wavelength absorbed by the measurement target gas but also the intensity of the light having the measurement wavelength absorbed by the interfering gas is detected by the detector, so that the concentration of the measurement target gas cannot be accurately measured.

[0005] Therefore, as shown in Patent Document 1, in the above-described conventional absorption analysis system, a plurality of detectors capable of detecting the intensity of light having the measurement wavelength are used, and a simultaneous equation related to the intensity of light having each measurement wavelength detected by the detector is solved to calculate the concentrations of the measurement target gas and the interfering gas.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-101416 Summary of the Invention

[0009] Technical Problem

[0010] A main object of the present invention is to provide an absorption analysis system that can accurately measure the concentration of a measurement target gas with high precision based on the intensity of light transmitted through a gas including an interfering gas even without using a plurality of detectors that detect the intensity of light having the measurement wavelength.

[0011] Technical Solution

[0012] That is, the light absorption analysis system of the present invention is characterized by including: a detector that detects the intensity of light transmitted through a gas; a total pressure sensor that measures the total pressure of the gas; an interfering gas partial pressure - absorbance relationship storage unit that stores interfering gas partial pressure - absorbance relationship data, where the interfering gas partial pressure - absorbance relationship data represents the relationship between the partial pressure of an interfering gas contained in the gas together with the gas to be measured and the absorbance; an interfering gas partial pressure estimation unit that estimates the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor; an interfering gas absorbance conversion unit that converts the estimated partial pressure of the interfering gas estimated by the interfering gas partial pressure estimation unit into the absorbance of the interfering gas based on the interfering gas partial pressure - absorbance relationship data; and a gas to be measured absorbance calculation unit that calculates the absorbance of the gas to be measured based on the output value of the detector and the absorbance of the interfering gas converted by the interfering gas absorbance conversion unit.

[0013] With such a configuration, the partial pressure of the interfering gas is estimated based on the total pressure measured by the total pressure sensor, the estimated partial pressure of the interfering gas is converted into the absorbance of the interfering gas based on the interfering gas partial pressure - absorbance relationship data that represents the relationship between the partial pressure and absorbance of the interfering gas stored in advance, and the absorbance of the gas to be measured is calculated based on the absorbance of the interfering gas and the output value of the detector. Therefore, even without using a detector that detects the intensity of light at multiple measurement wavelengths, the concentration of the gas to be measured can be calculated with high accuracy based on the output value of the detector.

[0014] It should be noted that in semiconductor manufacturing processes, a gas with a lower concentration of the gas to be measured than that of the interfering gas is mostly supplied to the supply target. In this case, the total pressure measured by the total pressure sensor can be approximately estimated as the partial pressure of the interfering gas. It should be noted that when calculating the concentration of the gas to be measured, even if such an approximation is made, the influence of the error caused by this approximation is smaller than the error caused by the influence of the interfering gas on the intensity of the light detected by the detector. Therefore, the concentration of the gas to be measured can also be calculated with high accuracy as a result.

[0015] Here, the absorbance in the interfering gas partial pressure - absorbance relationship data represents the absorbance of the interfering gas calculated based on the output value detected by the detector included in the light absorption analysis system.

[0016] Therefore, the interfering gas partial pressure estimation unit may also be configured to estimate the total pressure measured by the total pressure sensor as the partial pressure of the interfering gas.

[0017] It should be noted that as a specific configuration of the above light absorption analysis system, the following light absorption analysis systems can be cited: It further includes: a measurement target gas partial pressure - absorbance relationship storage unit that stores measurement target gas partial pressure - absorbance relationship data indicating the relationship between the partial pressure of the measurement target gas contained in the above gas and the absorbance; and a measurement target gas partial pressure conversion unit that converts the measurement target gas absorbance calculated by the above measurement target gas absorbance calculation unit into the partial pressure of the above measurement target gas based on the above measurement target gas partial pressure - absorbance relationship data. In addition, a light absorption analysis system further including an interfering gas partial pressure calculation unit can be cited. The above interfering gas partial pressure calculation unit calculates the partial pressure of the above interfering gas based on the total pressure measured by the above total pressure sensor and the partial pressure of the measurement target gas converted by the above measurement target gas partial pressure conversion unit.

[0018] Here, the absorbance in the measurement target gas partial pressure - absorbance relationship data represents the absorbance of the measurement target gas calculated based on the output value detected by the detector included in the light absorption analysis system.

[0019] In addition, when it is desired to calculate the concentration of the measurement target gas with higher accuracy in the above light absorption analysis system, it can be set to include a second interfering gas absorbance conversion unit. The above second interfering gas absorbance conversion unit converts the calculated interfering gas calculated partial pressure calculated by the above interfering gas partial pressure calculation unit into a new absorbance of the above interfering gas based on the above interfering gas partial pressure - absorbance relationship data. The above measurement target gas absorbance calculation unit calculates a new absorbance of the above measurement target gas based on the output value of the above detector and the new absorbance of the interfering gas converted by the above second interfering gas absorbance conversion unit.

[0020] In such a system, the interfering gas calculated partial pressure calculated by the interfering gas partial pressure calculation unit is closer to the actual interfering gas partial pressure than the interfering gas estimated partial pressure estimated by the interfering gas partial pressure estimation unit. Therefore, by converting the interfering gas calculated partial pressure calculated by the interfering gas partial pressure calculation unit into a new absorbance of the interfering gas and recalculating the new absorbance of the measurement target gas based on this new absorbance of the interfering gas, it is possible to calculate the concentration of the measurement target gas with higher accuracy.

[0021] In addition, the program storage medium for the absorption analysis system of the present invention is characterized in that it stores a program for the absorption analysis system. The absorption analysis system includes: a detector that detects the intensity of light transmitted through a gas, and a total pressure sensor that measures the total pressure of the gas. The program for the absorption analysis system causes a computer to function as a disturbance gas partial pressure - absorbance relationship storage unit, a disturbance gas partial pressure estimation unit, a disturbance gas absorbance conversion unit, and a measurement target gas absorbance calculation unit. The disturbance gas partial pressure - absorbance relationship storage unit stores disturbance gas partial pressure - absorbance relationship data, and the disturbance gas partial pressure - absorbance relationship data represents the relationship between the partial pressure and absorbance of a disturbance gas contained in the gas together with the measurement target gas. The disturbance gas partial pressure estimation unit estimates the partial pressure of the disturbance gas based on the total pressure measured by the total pressure sensor. The disturbance gas absorbance conversion unit converts the estimated partial pressure of the disturbance gas estimated by the disturbance gas partial pressure estimation unit into the absorbance of the disturbance gas based on the disturbance gas partial pressure - absorbance relationship data. The measurement target gas absorbance calculation unit calculates the absorbance of the measurement target gas based on the output value of the detector and the absorbance of the disturbance gas converted by the disturbance gas absorbance conversion unit.

[0022] In addition, the absorption analysis device of the present invention is characterized in that it is used for an absorption analysis system. The absorption analysis system includes: a detector that detects the intensity of light transmitted through a gas, and a total pressure sensor that measures the total pressure of the gas. The absorption analysis device includes: a disturbance gas partial pressure - absorbance relationship storage unit that stores disturbance gas partial pressure - absorbance relationship data, and the disturbance gas partial pressure - absorbance relationship data represents the relationship between the partial pressure and absorbance of a disturbance gas contained in the gas together with the measurement target gas; a disturbance gas partial pressure estimation unit that estimates the partial pressure of the disturbance gas based on the total pressure measured by the total pressure sensor; a disturbance gas absorbance conversion unit that converts the estimated partial pressure of the disturbance gas estimated by the disturbance gas partial pressure estimation unit into the absorbance of the disturbance gas based on the disturbance gas partial pressure - absorbance relationship data; and a measurement target gas absorbance calculation unit that calculates the absorbance of the measurement target gas based on the output value of the detector and the absorbance of the disturbance gas converted by the disturbance gas absorbance conversion unit.

[0023] In addition, the absorbance measurement method of the present invention is characterized in that it is a method for measuring the absorbance of a measurement target gas contained in a gas by using an absorption analysis system. The absorption analysis system includes: a detector for detecting the intensity of light transmitted through the gas, and a total pressure sensor for measuring the total pressure of the gas. The absorbance measurement method includes: a first step of storing interference gas partial pressure-absorbance relationship data, which represents the relationship between the partial pressure of an interference gas contained in the gas together with the measurement target gas and the absorbance; a second step of estimating the partial pressure of the interference gas based on the total pressure measured by the total pressure sensor and the predicted concentration of the interference gas; a third step of converting the estimated partial pressure of the interference gas estimated in the second step into the absorbance of the interference gas based on the interference gas partial pressure-absorbance relationship data; and a fourth step of calculating the absorbance of the measurement target gas based on the absorbance of the interference gas converted in the third step and the output value of the detector.

[0024] Technical effects

[0025] According to the absorption analysis system configured as such, even without using a detector for detecting the intensities of light at multiple measurement wavelengths, it is possible to accurately measure the concentration of the measurement target gas based on the intensity of light transmitted through the gas containing the interference gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram showing the overall structure of the absorption analysis system of the embodiment.

[0027] Figure 2 It is a schematic diagram showing the structure of the detector of the absorption analysis system of the embodiment.

[0028] Figure 3 It is a schematic diagram showing the structure of a modified example of the detector of the absorption analysis system of the embodiment.

[0029] Figure 4 It is a block diagram showing the functions of the absorption analysis device of the embodiment.

[0030] Figure 5 It is a chart schematically showing an example of the interference gas partial pressure-absorbance relationship data for the absorption analysis device of the embodiment.

[0031] Figure 6 It is a flowchart showing the operation of the absorption analysis device of the embodiment.

[0032] Figure 7 It is a block diagram showing the functions of the absorption analysis device of another embodiment.

[0033] Figure 8 It is a flowchart showing the operation of an absorption analysis apparatus according to another embodiment.

[0034] Symbol Explanation

[0035] 100 Absorption analysis system

[0036] L Flow path

[0037] 10 Total pressure sensor

[0038] 20 Detector

[0039] C Absorption analysis apparatus

[0040] C1 Interference gas partial pressure - absorbance relationship storage unit

[0041] C2 Interference gas partial pressure estimation unit

[0042] C3 Interference gas absorbance conversion unit

[0043] C4 Measurement target gas absorbance calculation unit

[0044] C5 Measurement target gas partial pressure - absorbance relationship storage unit

[0045] C6 Measurement target gas partial pressure conversion unit

[0046] C7 Measurement target gas concentration calculation unit

[0047] C8 Interference gas partial pressure calculation unit

[0048] C9 Second interference gas absorbance conversion unit

[0049] C10 Conversion times counting unit

[0050] C11 Counting times determination unit Detailed Embodiment

[0051] Hereinafter, an absorption analysis system according to an embodiment of the present invention will be described based on the drawings.

[0052] The absorption analysis system of the present embodiment is a system that is installed, for example, in a semiconductor production line or the like and is used to measure the concentration of a measurement target gas contained in a gas supplied to a supply target together with an interference gas.

[0053] As Figure 1 shown, the absorption analysis system 100 of the present embodiment includes: a flow path L for supplying gas to a chamber CH (supply target), a total pressure sensor 10 provided in the flow path L, a detector 20 provided at a position closer to the downstream side of the flow path L than the total pressure sensor 10, and an absorption analysis apparatus C.

[0054] The above total pressure sensor 10 is a sensor that measures the total pressure of the gas flowing in the flow path L.

[0055] The above detector 20 detects the intensity of light transmitted through the gas flowing in the flow path L. Specifically, as Figure 2 shown, the detector 20 includes: a light source 21 that irradiates light on the gas flowing in the flow path L, a filter 22 that allows light of the wavelength absorbed by the gas to be measured (hereinafter, also referred to as the measurement wavelength) among the wavelengths of the light emitted from the light source 21 to pass through, and a light receiving unit 23 that detects the intensity of the light of the measurement wavelength that has passed through the filter 22. It should be noted that when the region through which the light emitted from the light source 21 in the flow path L passes is set as the measurement region Z, the detector 20 has the light source 21 arranged on one side of the measurement region Z, and the filter 22 and the light receiving unit 23 arranged on the other side of the measurement region Z. In addition, window members 24 are respectively provided between the light source 21 and the flow path L and between the filter 22 and the flow path L. Thus, the light source 21, the filter 22, and the light receiving unit 23 do not come into direct contact with the gas flowing in the flow path L. Moreover, the detector 20 outputs an output signal indicating the intensity of the light transmitted through the gas present in the measurement region Z from the light receiving unit 23 as an output value.

[0056] It should be noted that, as Figure 3 shown, in addition to the filter 22 and the light receiving unit 23, the above detector 20 on the other side of the measurement region Z may further include a reference filter 22r that allows light of a wavelength not absorbed by the material gas to pass through, and a reference light receiving unit 23r that detects the intensity of the light of the wavelength that has passed through the reference filter 22r. In this case, the ratio of the output signal of the light receiving unit 23 to the output signal of the reference light receiving unit 23r may also be used as the output value of the detector 20.

[0057] The above absorption analysis device C is a device that calculates the concentration of the gas to be measured, etc., and is at least connected to the total pressure sensor 10 and the detector 20. Specifically, it is a computer having a CPU, a memory, an AD converter, a DA converter, an input unit, etc., and is configured to execute the program stored in the above memory by using the CPU, so that as Figure 4 shown, it functions as an interference gas partial pressure - absorbance relationship storage unit C1, an interference gas partial pressure estimation unit C2, an interference gas absorbance conversion unit C3, a measurement object gas absorbance calculation unit C4, a measurement object gas partial pressure - absorbance relationship storage unit C5, a measurement object gas partial pressure conversion unit C6, a measurement object gas concentration calculation unit C7, etc.

[0058] The above-described interfering gas partial pressure - absorbance relationship storage unit C1 is a storage unit that stores interfering gas partial pressure - absorbance relationship data representing the relationship between the partial pressure of an interfering gas and absorbance. For example, the interfering gas partial pressure - absorbance relationship storage unit C1 circulates an interfering gas with a known concentration in the flow path L before the light absorption analysis system 100 is shipped or before measurement after shipment. At this time, data representing the relationship between the partial pressure of the interfering gas present in the measurement region Z of the detector 20 and absorbance is acquired in advance, and this data is stored as the interfering gas partial pressure - absorbance relationship data. It should be noted that the partial pressure of the interfering gas can be calculated based on the total pressure measured by the total pressure sensor 10 and the known concentration of the interfering gas. In addition, the absorbance of the interfering gas can be calculated based on the output value detected by the detector 20. Incidentally, the interfering gas partial pressure - absorbance relationship data is obtained, for example, as a graph that shows the relationship between the partial pressure of the interfering gas and absorbance, with the partial pressure of the interfering gas on the vertical axis and absorbance on the horizontal axis as shown in Figure 5 . It should be noted that when an interfering gas is used as a calibration gas for calibrating the detector 20 before the light absorption analysis system 100 is shipped, the interfering gas partial pressure - absorbance relationship data coincides with the standard curve data used in this calibration. It should be noted that the interfering gas partial pressure - absorbance relationship data can be input to the interfering gas partial pressure - absorbance relationship storage unit C1 via the input unit.

[0059] When a gas is flowing in the flow path L, the above-described interfering gas partial pressure estimation unit C2 estimates the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor 10. For example, when the concentration of the measurement target gas contained in the gas is low, the interfering gas partial pressure estimation unit C2 estimates the total pressure detected by the total pressure sensor 10 as the partial pressure of the interfering gas. Incidentally, the case where the concentration of the measurement target gas contained in the gas is low means, for example, a case where the measurement target gas is contained in the gas in a percentage. In this case, the estimated partial pressure of the interfering gas includes an error caused by the partial pressure of the measurement target gas. In addition, when the concentration of the measurement target gas contained in the gas is not low, the interfering gas partial pressure estimation unit C2 estimates the partial pressure of the interfering gas based on the predicted concentration of the interfering gas and the above-described total pressure.

[0060] The above-described interfering gas absorbance conversion unit C3 converts the estimated partial pressure of the interfering gas estimated by the interfering gas partial pressure estimation unit C2 into the absorbance of the interfering gas based on the interfering gas partial pressure - absorbance relationship data.

[0061] When gas is flowing in the flow path L, the measurement target gas absorbance calculation unit C4 calculates the absorbance of the measurement target gas based on the output value of the detector 20 and the absorbance of the interfering gas converted by the interfering gas absorbance conversion unit C3. Specifically, the measurement target gas absorbance calculation unit C4 uses the value obtained by subtracting the absorbance of the interfering gas from the absorbance calculated from the output value of the detector 20 as the absorbance of the measurement target gas.

[0062] The above-mentioned measurement target gas partial pressure-absorbance relationship storage unit C5 stores measurement target gas partial pressure-absorbance relationship data representing the relationship between the partial pressure and absorbance of the measurement target gas. For example, the measurement target gas partial pressure-absorbance relationship storage unit C5 circulates a measurement target gas with a known concentration in the flow path L before the light absorption analysis system 100 is shipped or before measurement after shipment. At this time, data representing the relationship between the partial pressure and absorbance of the measurement target gas present in the measurement region Z of the detector 20 is obtained in advance and stored as the measurement target gas partial pressure-absorbance relationship data. It should be noted that the partial pressure of the measurement target gas can be calculated based on the total pressure measured by the total pressure sensor 10 and the known concentration of the measurement target gas. In addition, the absorbance of the measurement target gas can be calculated based on the output value detected by the detector 20. It should be noted that the measurement target gas partial pressure-absorbance relationship data can be input to the measurement target gas partial pressure-absorbance relationship storage unit C5 through the input unit.

[0063] The above-mentioned measurement target gas partial pressure conversion unit C6 converts the absorbance of the measurement target gas calculated by the measurement target gas absorbance calculation unit C4 into the partial pressure of the measurement target gas. Specifically, the measurement target gas partial pressure conversion unit C6 converts the absorbance of the measurement target gas into the partial pressure of the measurement target gas based on the measurement target gas partial pressure-absorbance relationship data.

[0064] The above-mentioned measurement target gas concentration calculation unit C7 calculates the concentration of the measurement target gas based on the total pressure 10 measured by the total pressure sensor 10 and the partial pressure of the measurement target gas converted by the measurement target gas partial pressure conversion unit C6, and displays it on the display unit.

[0065] Next, the operation of the light absorption analysis device C of the present embodiment will be described.

[0066] First, in a state where gas is flowing through the flow path L, if a measurement start signal is input to the absorption analysis device C, the interfering gas partial pressure estimation unit C2 receives a total pressure signal indicating the total pressure measured by the total pressure sensor 10 (step S1). Then, the interfering gas partial pressure estimation unit C2 estimates the partial pressure of the interfering gas contained in the gas based on the pressure indicated by the received total pressure signal (step S2). It should be noted that in step S2, when the concentration of the interfering gas contained in the gas is low, the pressure indicated by the received total pressure signal may also be estimated as the partial pressure of the interfering gas contained in the gas.

[0067] Next, the interfering gas absorbance conversion unit C3 refers to the interfering gas partial pressure-absorbance relationship data and converts the estimated partial pressure of the interfering gas estimated by the interfering gas partial pressure estimation unit C2 into the absorbance of the interfering gas (step S3).

[0068] Next, the measurement target gas absorbance calculation unit C4 receives a gas absorbance signal indicating the absorbance calculated based on the output value of the detector 20 (step S4). Then, the measurement target gas absorbance calculation unit C4 regards the difference between the gas absorbance indicated by the gas absorbance signal and the absorbance of the interfering gas converted by the interfering gas absorbance conversion unit C3 as the absorbance of the measurement target gas (step S5).

[0069] Next, the measurement target gas partial pressure conversion unit C6 refers to the measurement target gas partial pressure-absorbance relationship data and converts the absorbance of the measurement target gas calculated by the measurement target gas absorbance calculation unit C4 into the partial pressure of the measurement target gas (step S6).

[0070] Then, the measurement target gas concentration calculation unit C7 calculates the measurement target gas concentration based on the total pressure measured by the total pressure sensor 10 and the partial pressure of the measurement target gas converted by the measurement target gas partial pressure conversion unit C6 (step S7). It should be noted that the measurement target gas concentration calculation unit C7 displays the calculated measurement target gas concentration on the display unit (step S8).

[0071] <Another Embodiment> As a modification example of the absorption analysis device C in the above embodiment, the following device can be cited. In addition to functioning as an interfering gas partial pressure-absorbance relationship storage unit C1, an interfering gas partial pressure estimation unit C2, an interfering gas absorbance conversion unit C3, a measurement target gas absorbance calculation unit C4, a measurement target gas partial pressure-absorbance relationship storage unit C5, a measurement target gas partial pressure conversion unit C6, and a measurement target gas concentration calculation unit C7, it also functions as an interfering gas partial pressure calculation unit C8, a second interfering gas absorbance conversion unit C9, a conversion times counting unit C10, and a counted times determination unit C11.

[0072] The above-described interfering gas partial pressure calculation unit C8 calculates the interfering gas partial pressure based on the total pressure measured by the total pressure sensor 10 and the measured object gas partial pressure converted by the measured object gas partial pressure conversion unit C6. Specifically, the interfering gas partial pressure calculation unit C8 takes the difference between the total pressure and the measured object gas partial pressure as the interfering gas partial pressure.

[0073] The above-described second interfering gas absorbance conversion unit C9 converts the interfering gas partial pressure calculated by the interfering gas partial pressure calculation unit C8 into a new absorbance of the interfering gas with reference to the interfering gas partial pressure-absorbance relationship data.

[0074] The above-described conversion times counting unit C10 counts the number of times of conversion into the interfering gas absorbance by the interfering gas absorbance conversion unit C3 and the second interfering gas absorbance conversion unit C9.

[0075] The above-described counted times determination unit C11 determines whether the counted times by the conversion times counting unit C10 have reached the set times. Specifically, the counted times determination unit C11 determines whether the counted times have reached the set times of two or more set in advance.

[0076] Next, the operation of the absorbance analysis device C of the above-described another embodiment will be described.

[0077] In the present embodiment, between step S3 and step S4 in the operation of the absorbance analysis device C of the above-described embodiment, the number of times of conversion into the interfering gas absorbance is counted (step S9). Further, in the present embodiment, between step S6 and step S7 in the operation of the absorbance analysis device C of the above-described embodiment, it is determined whether the number of times of conversion into the interfering gas absorbance (counted times) has reached the set times (step S10).

[0078] Then, when it is determined that the number of times of conversion into the interfering gas absorbance has reached the set times, the process proceeds to step S7 and step S8, and the concentration of the measured object gas is displayed on the display unit.

[0079] On the other hand, when it is determined that the number of times of converting to the absorbance of the interfering gas has not reached the set number of times, the interfering gas partial pressure calculation unit C8 calculates the interfering gas partial pressure based on the total pressure measured by the total pressure sensor 10 and the partial pressure of the gas to be measured obtained by the gas to be measured partial pressure conversion unit C6 (step S11). Then, the second interfering gas absorbance conversion unit C9 refers to the interfering gas partial pressure-absorbance relationship data and converts the interfering gas partial pressure calculated by the interfering gas partial pressure calculation unit C8 into a new absorbance of the interfering gas (step S12). Then, through steps S4 to S6, the partial pressure of the gas to be measured is derived based on the new absorbance of the interfering gas converted by the second interfering gas absorbance conversion unit C9. It should be noted that the operation steps S9, steps S4 to S6, and steps S10 to S12 are repeatedly cycled until the count number of the conversion number counting unit C10 reaches the set number of times.

[0080] It should be noted that in the above-described another embodiment, it is configured to count the number of cycles and end the cycle when the counted number reaches the set number of times. However, it may also be configured to, for example, determine whether the difference between the partial pressure of the gas to be measured calculated in the previous cycle (for example, the previous cycle) and the partial pressure of the gas to be measured calculated in the current cycle is less than a predetermined value, and end the cycle when it is equal to or less than the predetermined value.

[0081] If it is configured in this way, as the number of conversions of the second interfering gas absorbance conversion unit C9 increases, the error contained in the partial pressure of the gas to be measured becomes smaller. Specifically, by estimating the interfering gas partial pressure based on the total pressure measured by the total pressure sensor 10 in the interfering gas partial pressure estimation unit C2, the proportion of the error of the gas to be measured contained in the estimated interfering gas partial pressure becomes smaller. As a result, the measurement accuracy of the concentration of the gas to be measured is improved.

[0082] In addition, in the above-described embodiment, the total pressure sensor 10 is provided at a position upstream of the flow path L closer to the detector 20. However, in this case, due to the pressure loss generated between the measurement region Z of the detector 20 and the measurement point of the total pressure sensor 10, only the total pressure affected by the pressure loss can be detected by the total pressure sensor 10. Therefore, it is preferable to, for example, as Figure 2 shown by the dotted line in, the total pressure sensor 10 is provided so that the measurement point of the total pressure sensor 10 coincides with the measurement region Z of the detector 20. Specifically, it is preferable to provide the total pressure sensor 10 so that the measurement point of the total pressure sensor 10 is located on the optical axis ( Figure 2 in, indicated by the single-dot chain line) of the light emitted from the light source 21 of the detector 20.

[0083] It should be noted that in the above-described embodiment, a method is exemplified in which, in the measurement target gas partial pressure - absorbance relationship storage unit C5, when acquiring the measurement target gas partial pressure - absorbance relationship data, a measurement target gas with a known concentration is passed through the detector 20, but it is not limited thereto. For example, a substitute gas whose relationship between the partial pressure and the absorbance has a known correlation with the measurement target gas is caused to flow through the detector 20. At this time, data representing the relationship between the partial pressure and the absorbance of the substitute gas present in the measurement region Z of the detector 20 is acquired in advance. Then, based on this data and the above-described known correlation, the measurement target gas partial pressure - absorbance relationship data can also be acquired. The same can be said for the interfering gas partial pressure - absorbance relationship storage unit C3.

[0084] In addition, the present invention is not limited to the above-described embodiments, and various modifications can of course be made without departing from the gist thereof.

Claims

1. An absorbance analysis system, characterized in that, Comprising: A light source that irradiates light onto a mixed gas, the mixed gas including a measurement target gas that absorbs light of a predetermined measurement wavelength and an interfering gas; A detector that detects the intensity of the light of the measurement wavelength that has passed through the mixed gas; A total pressure sensor that measures the total pressure of the mixed gas irradiated with light; An interfering gas partial pressure - absorbance relationship storage unit that stores interfering gas partial pressure - absorbance relationship data, the interfering gas partial pressure - absorbance relationship data representing the relationship between the partial pressure of the interfering gas contained in the mixed gas and the absorbance of the interfering gas at the measurement wavelength; An interfering gas partial pressure estimation unit that estimates the partial pressure of the interfering gas in the mixed gas irradiated with light based on the total pressure measured by the total pressure sensor; An interfering gas absorbance conversion unit that converts the estimated interfering gas partial pressure estimated by the interfering gas partial pressure estimation unit into the absorbance of the interfering gas at the measurement wavelength based on the interfering gas partial pressure - absorbance relationship data; And A measurement target gas absorbance calculation unit that calculates the absorbance of the measurement target gas at the measurement wavelength based on the output value of the detector and the absorbance of the interfering gas converted by the interfering gas absorbance conversion unit, Estimating the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor is any of the following cases: Presuming the total pressure measured by the total pressure sensor as the partial pressure of the interfering gas; and Estimating the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor and the predicted concentration of the interfering gas.

2. The absorbance analysis system according to claim 1, characterized in that, The interfering gas partial pressure estimation unit presumes the total pressure measured by the total pressure sensor as the partial pressure of the interfering gas.

3. The absorbance analysis system according to claim 1, characterized in that, The absorbance analysis system further comprises: A measurement target gas partial pressure - absorbance relationship storage unit that stores measurement target gas partial pressure - absorbance relationship data representing the relationship between the partial pressure and absorbance of the measurement target gas contained in the gas; And A measurement target gas partial pressure conversion unit that converts the absorbance of the measurement target gas calculated by the measurement target gas absorbance calculation unit into the partial pressure of the measurement target gas based on the measurement target gas partial pressure - absorbance relationship data.

4. The absorbance analysis system according to claim 3, characterized in that, The absorbance analysis system further comprises an interfering gas partial pressure calculation unit that calculates the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor and the partial pressure of the measurement target gas converted by the measurement target gas partial pressure conversion unit.

5. The absorbance analysis system according to claim 4, characterized in that, The absorbance analysis system further comprises a second interfering gas absorbance conversion unit that converts the calculated interfering gas partial pressure calculated by the interfering gas partial pressure calculation unit into a new absorbance of the interfering gas based on the interfering gas partial pressure - absorbance relationship data, The measurement target gas absorbance calculation unit calculates a new absorbance of the measurement target gas based on the output value of the detector and the new absorbance of the interfering gas converted by the second interfering gas absorbance conversion unit.

6. A program storage medium, characterized in that, A program for an absorption analysis system is stored. The absorption analysis system includes: a light source that irradiates a mixed gas including a measurement target gas that absorbs light of a predetermined measurement wavelength and an interfering gas with light, a detector that detects the intensity of the light of the measurement wavelength that has passed through the mixed gas, and a total pressure sensor that measures the total pressure of the mixed gas irradiated with light. The program for the absorption analysis system causes a computer to function as an interfering gas partial pressure - absorbance relationship storage unit, an interfering gas partial pressure estimation unit, an interfering gas absorbance conversion unit, and a measurement target gas absorbance calculation unit. The interfering gas partial pressure - absorbance relationship storage unit stores interfering gas partial pressure - absorbance relationship data, and the interfering gas partial pressure - absorbance relationship data represents the relationship between the partial pressure of the interfering gas contained in the mixed gas and the absorbance of the interfering gas at the measurement wavelength. The interfering gas partial pressure estimation unit estimates the partial pressure of the interfering gas in the mixed gas irradiated with light based on the total pressure measured by the total pressure sensor. The interfering gas absorbance conversion unit converts the estimated partial pressure of the interfering gas estimated by the interfering gas partial pressure estimation unit into the absorbance of the interfering gas at the measurement wavelength based on the interfering gas partial pressure - absorbance relationship data. The measurement target gas absorbance calculation unit calculates the absorbance of the measurement target gas at the measurement wavelength based on the output value of the detector and the absorbance of the interfering gas converted by the interfering gas absorbance conversion unit. Estimating the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor is any of the following cases: estimating the total pressure measured by the total pressure sensor as the partial pressure of the interfering gas; and estimating the partial pressure of the interfering gas based on the total pressure measured by the total pressure sensor and the predicted concentration of the interfering gas.

7. An absorbance analysis device, characterized in that, It is used for an absorption analysis system, and the absorption analysis system includes: a light source that irradiates a mixed gas including a measurement target gas that absorbs light of a predetermined measurement wavelength and an interfering gas with light, a detector that detects the intensity of the light of the measurement wavelength that has passed through the mixed gas, and a total pressure sensor that measures the total pressure of the mixed gas irradiated with light. The absorption analysis device includes: An interfering gas partial pressure - absorbance relationship storage unit that stores interfering gas partial pressure - absorbance relationship data, and the interfering gas partial pressure - absorbance relationship data represents the relationship between the partial pressure of the interfering gas contained in the mixed gas and the absorbance of the interfering gas at the measurement wavelength; An interfering gas partial pressure estimation unit that estimates the partial pressure of the interfering gas in the mixed gas irradiated with light based on the total pressure measured by the total pressure sensor; An interfering gas absorbance conversion unit that converts the estimated partial pressure of the interfering gas estimated by the interfering gas partial pressure estimation unit into the absorbance of the interfering gas at the measurement wavelength based on the interfering gas partial pressure - absorbance relationship data; And A measurement target gas absorbance calculation unit that calculates the absorbance of the measurement target gas at the measurement wavelength based on the output value of the detector and the absorbance of the interfering gas converted by the interfering gas absorbance conversion unit. The partial pressure of the interfering gas is estimated based on the total pressure measured by the total pressure sensor in any of the following cases: the total pressure measured by the total pressure sensor is estimated as the partial pressure of the interfering gas; and the partial pressure of the interfering gas is estimated based on the total pressure measured by the total pressure sensor and the predicted concentration of the interfering gas.

8. An absorbance measurement method, characterized in that, It is a method for measuring the absorbance of a measurement target gas contained in a gas using an absorption analysis system. The absorption analysis system includes: a light source that irradiates light on a mixed gas including the measurement target gas that absorbs light of a predetermined measurement wavelength and an interfering gas, a detector that detects the intensity of the light of the measurement wavelength that has passed through the mixed gas, and a total pressure sensor that measures the total pressure of the mixed gas irradiated with light. The absorbance measurement method includes: A first step of storing interfering gas partial pressure-absorbance relationship data, which represents the relationship between the partial pressure of the interfering gas contained in the mixed gas irradiated with light and the absorbance of the interfering gas at the measurement wavelength. A second step of estimating the partial pressure of the interfering gas in the mixed gas irradiated with light based on the total pressure of the mixed gas measured by the total pressure sensor. The partial pressure of the interfering gas is estimated based on the total pressure measured by the total pressure sensor in any of the following cases: the total pressure measured by the total pressure sensor is estimated as the partial pressure of the interfering gas; and the partial pressure of the interfering gas is estimated based on the total pressure measured by the total pressure sensor and the predicted concentration of the interfering gas. A third step of converting the estimated partial pressure of the interfering gas estimated in the second step into the absorbance of the interfering gas at the measurement wavelength based on the interfering gas partial pressure-absorbance relationship data; and A fourth step of calculating the absorbance of the measurement target gas at the measurement wavelength based on the absorbance of the interfering gas converted in the third step and the output value of the detector.

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