Cantilever enhanced fiber-optic photoacoustic microprobe for diffusion detection of sulfur dioxide

The detection of partial discharge through analysis of SF6 gas components in gas-insulated switchgear, is significant for the diagnosis and assessment of the operating state of power equipment. The present study proposes the use of a TiO2 nanotube array sensor for detecting the SF6 decomposition product SO2, and the application of the anodic oxidation method for the directional growth of highly ordered TiO2 nanotube arrays. The sensor response of 10–50 ppm SO2 gas is tested, and the sensitive response mechanism is discussed. The test results show that the TiO2 nanotube sensor array has good response to SO2 gas, and by ultraviolet radiation, the sensor can remove attached components very efficiently, shorten recovery time, reduce chemical poisoning, and prolong the life of the components.

We demonstrate a highly sensitive and stable fiber-optic Fabry-Perot cantilever microphone based on fast demodulated white-light interferometry. The cavity length of the low-finesse Fabry-Perot interferometry is absolutely measured by realizing a high-speed demodulation method utilizing a full spectrum, with the advantages of both high resolution and large dynamic range. An acoustic test demonstrates high sensitivities and linear responsivities at frequencies below 2 kHz. The pressure responsivity and the noise-limited minimum detectable acoustic pressure level are measured to be 211.2 nm/Pa and 5  μPa/Hz1/2, respectively, at the frequency of 1 kHz. Comparative experimental results show that the signal-to-noise ratio is over 10 times higher than a reference condenser microphone.