| 摘要 |
PURPOSE:To measure the concentration of gaseous hydrogen by embedding a light guide in a substrate, forming a light absorbing layer which varies in coefficient of light absorption by reaction on dissociated hydrogen on the surface of the substrate, and providing a dissociative absorbing layer for gaseous hydrogen thereupon. CONSTITUTION:The light guide 2 which is larger in refractive index than the substrate is embedded in one body, and the light absorbing layer 3 made of a dielectric which varies in coefficient of light absorption by reaction on dissociated hydrogen and the adsorbing layer 4 made of a material which dissociate and adsorbs gaseous hydrogen are provided on the surface of the substrate to a sensor. Light from a light source 6 is made incident through one fiber 5A and the quantity of projection light from the other fiber 5B is measured by a photodetector 7. When hydrogen is adsorbed to the surface of the adsorbing layer of the sensor to cause dissociation, generated electrons and protons are received by the light absorbing layer under the adsorbing layer, so that the light absorbing layer increases in coefficient of light absorption. Consequently, the ratio of absorptive attenuation of an evanescent wave from the light guide to the light absorbing layer or light leaking from the light guide by the absorbing layer increases. The increase in coefficient of light absorption is proportional to the concentration of adsorbed gaseous hydrogen, so the concentration of the gaseous hydrogen is known. |
