Patent ID: 6185344
Filing Date: 2001-02-06
Classification: G01N,G02B

Abstract:
An optical device for in situ detection of traces of gaseous hydrogen in an environment at cryogenic temperature, using a sensor having a fine film of palladium whose optical properties vary as a function of the concentration of hydrogen in contact with the film, the device comprising a palladium micromirror deposited in the form of a film at a first end of a first optical fiber, a first light source emitting a light signal at a predetermined wavelength into a second end of the first optical fiber, means for detecting the light signal as modified after passing in contact with the palladium micromirror that is disposed in the environment at cryogenic temperature, processor circuits for responding to variation in the intensity of the light signal that has been in contact with the palladium micromirror to determine the hydrogen concentration, and localized heating means for heating the palladium micromirror by light radiation, so as to maintain the micromirror in the .alpha. phase of palladium.