摘要 |
PURPOSE:To enable detection of hydrogen stably eliminating change due to aging or influence of gaseous impurities by detecting reduction of solid compds. by the hydrogen adsorbed by a laminated metal by the difference between the signal of photo detection of wavelength causing large change of light absorption and wavelength causing small change of light absorption. CONSTITUTION:An element 1 is formed by laminating a catalyst metal 2 which adsorbs and dissociates gaseous H2 or H2-contg. gas, and a solid compd. 3 causing change of light absorption at a specified wavelength by reducing with H atoms contained in the metal 2. The element 1 is irradiated with light having above described specified wavelength from a light source 4, and the light having wavelength causing almost no change of light absorption even if the compd. 3 is reduced is irradiated from a light 5. By comparing the output of photodetector 6, 7 from the discrimination section 8, presence or absence of gaseous hydrogen is detected. |