Abstract: To improve the accuracy and sensitivity of vacuum partial pressure measurement and make up for the inherent defects of traditional measurement methods,the vacuum partial pressure will be characterized by gas density in combination with the ideal gas law.By using the infrared absorption spectrum of gas molecules and measuring the absorption of specific wavelength light by dual-comb spectroscopy,the density of target gas in mixed gas can be accurately measured,and then the vacuum partial pressure can be inversely obtained.A vacuum partial pressure measurement system based on electro-optic dual-comb has been developed,combined with dual-comb heterodyne spectroscopy and cavity-enhanced spectroscopy,to achieve non-invasive,large dynamic,and high-speed vacuum partial pressure measurement.The vacuum partial pressure of CO₂ and CO in the ternary mixture of CO₂,CO and N₂ was measured.The relative errors were 2.84 % and 2.77 % respectively.Through the uncertainty analysis,it is concluded that the absorption line strength error is the most important uncertainty component in the vacuum partial pressure measurement.

Key words: Vacuum partial pressure, Electro-optic dual-comb, Absorption spectrum