Device and method for measuring water vapor content by using self-calibrating optical cavity ring-down spectroscopy

Abstract

The invention discloses a device for measuring the water vapor content in a gas by using an optical cavity ring-down spectroscopy to self-calibrate a measurement unit. The device comprises a laser, an optical ring-down cavity, an photoelectric detector and a data collector, wherein the laser is used for outputting laser to the optical ring-down cavity; the optical ring-down cavity is an optical resonant cavity and is used for receiving the gas to be measured and allows the incoming laser to reflect back and forth repeatedly and outputs laser that gradually rings down; the photoelectric detector is receiving the laser emitted by the optical ring-down cavity, and generates an electrical signal according to the light intensity of the emitted laser, the ring-down time can be calculated by using the electrical signal, and the ring-down time can be used for calculating the water vapor content of the gas to be measured; and the trigger data collector is used for receiving and recording the electrical signal output by the photoelectric detector. According to the invention, the self-calibration of the measurement unit is realized based on the optical cavity ring-down spectroscopy by using the fixed optical cavity length, and the requirement of accurate quantitative measurement is achieved.

Description

technical field [0001] The invention belongs to the technical field of water vapor content measurement, in particular relates to calibration of water vapor content measurement, in particular to a device and method for measuring water vapor content by using self-calibrating optical cavity ring-down spectrum. Background technique [0002] The water vapor content in gases is an important parameter that must be observed in climate observations and many industrial applications. The humidity of a gas can be obtained by measuring the water vapor content. There are three main methods of measuring humidity at present. One is the wet and dry bulb method, which is to use two thermometers of exactly the same specification under the same wind speed, one dry and one wet, measure the temperature difference between the two thermometers, and then calculate the relative humidity. The operation is simple, but the accuracy is very low. Only 5% to 7% relative humidity. The other is the electr...

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Problems solved by technology

[0008] The technical problem to be solved by the present invention is that the traditional humidity measurement method has low measurement accuracy and small dynamic range for water vapor content, and it is difficult to measure low temperature objects.

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