Upgrade of neutron guides with use of supermirrors

Recent industrial developments of neutron supermirrors enable now the building of large surface elements, with an apparent critical angle double of the natural nickel, and a reflectivity of more than 90% on the extension of the total reflection plateau. Neutron guide G3-bis, and the curved part of the guide G2 on the Orphee reactor at Saclay (France) have been recently upgraded taking profit of this new technology. Thermal neutron flux and wavelength intensity distributions available at the end of guides G3-bis and G2 before and after this modification have been measured. An increase of flux of 69% on G3-bis, and 21% on G2 have been obtained. (author)