Abstract
In this study, leakage hydrogen gas was measured using Coherent Anti-Stokes Raman Spectroscopy (CARS) using a fiber-coupled, compact spectrometer. The Anti-Stokes light intensity was proportional to the square of the hydrogen gas density, which confirmed that the Anti-Stokes light was generated by CARS. When hydrogen gas was released from a nozzle, the spatial range in which the Anti-Stokes light could be detected was 1mm in the lateral direction directly above the nozzle. The dependence of the detectability of Anti-Stokes light on the material of a reflector placed behind the nozzle was investigated, which showed that Anti-Stokes light could be detected when the reflector was metal, rusted metal, or acrylic. The Anti-Stokes light could also be detected when low concentration (≦4%) hydrogen gas was released from the nozzle. The signal-to-noise ratio exceeded 1 when the concentration was over 0.4%. These results indicated the possibility of a hydrogen leak detector using CARS, to detect minute hydrogen gas leakage faster than conventional leak detectors.
