ISAC-1: radioactive ion beams facility at TRIUMF

This paper describes the ISAC-1 radioactive ion beam facility proposed at TRIUMF. A novel approach for the target/ion source station will allow an incident proton beam intensity of at least 10 μA at 500 MeV. This should give high luminosity for the production of nuclei far from stability with a very large isotopic range. After mass separation the beams can be sent to two different experimental areas. One uses the 60 keV energy beam for experiments such as the neutral atoms trap, parity violation, etc. The second one, mainly dedicated to nuclear astrophysics, will use the 0.2 to 1.5 MeV/u post-accelerated beam. Singly charged ion beams, with A⩽30 delivered from the on line mass separator, with an energy of 2 keV/u, will be accelerated in a two stage linac consisting of an RFQ and a post-stripper drift-tube linac up to 1.5 MeV/u. CW operation mode is required to preserve beam intensity. As a consequence of the low charge to mass ratio of the ions a low operating frequency for the RFQ is required to achieve adequate transverse focusing. The main features of this accelerator are: 35 MHz RFQ, stripping at 150 keV/u, and beam energy continuously variable from 0.2 keV/u to 1.5 MeV/u