Study on the laser-induced plasma properties of vacuum interrupter shield under different pressure

Vacuum degree online detection of vacuum interrupter has been investigated for more than 50 years. But, there is still no perferable means can be used to practical application. The change rules of Cu, H spectral lines intensities with pressure have been investigated in this paper. Further, the laser-induced plasma temperature and density are calculated using Boltzmann slope method and Stark broadening of Cu and H, respectively. Research results indicate that the H spectral line intensity increase with pressure from 0.001Pa to 1atm monotonically, which can be taken as characteristic signals of vacuum degree. In addition, the plasma temperature increase from ∼6500K to ∼12500K then decreased to ∼8000K. The plasma density increase from 1.8 × 10¹⁷cm⁻³ to 5.6 × 10¹⁷cm⁻³ monotonically when vacuum degree change from 0.001Pa to 100000Pa, which can be used as a supplementary measurement and verification of spectral lines intensities. A new vacuum degree online detection method is proposed in this paper which can overcome the poor electromagnetic interference ability, low limit of detection and hard to realize online detection of tradition methods. This method is significant to vacuum degree online detection of vacuum interrupter.