Réalisation d'une cellule d'absorption à réflexions multiples de grande dimension (longueur : 50 m)

We describe in this paper a 50 m long multiple reflection cell adapted to gaz phase absorption spectroscopic measurements. It conception and the use of a continuum light source powerful enough allow continuous records with path lengths up to 2 km at 2000 A and 4 km at 2700 A (essentially limited by the reflecting power of the mirrors). The experimental device, first studied for use in the UV (λ>2000 A) spectral range, is well adapted to the cases where the absorption cross sections and (or) the gaz pressures are small. Tests on oxygen absorption have been performed and preliminary resuls on the Herzberg bands and continuum are shown Cellule a reflexions multiples de grande dimension (50 m) parfaitement adaptee a des mesures de spectroscopie d'absorption UV en phase gazeuse