[en] The Isolde facility has been one of the main clients for beam time at the CERN synchrocyclotron since 1967. It was decided in 1983 to expand the capability of Isolde by the addition of a second primary proton target station and a second on-line isotope separator. At the same time it was decided to run the SC almost exclusively for Isolde in the future. The new separator has two stages of separation and has been designed so as to fit into existing buildings in order to keep the cost to a minimum. At present the separator is being installed, and we expect first beam towards the end of 1986. (author)