Bi-selective mass separator

During the SPIRAL2 “detailed engineering study” several designs for a mass separator were proposed. This separator should deliver, subsequently to the “production target/ion source system”, simultaneously two beams of different masses, one towards the low energy area (DESIR), the second towards the CIME post accelerator through the charge breeder). We had a hard time in following the specifications: two beam lines with a resolving power larger than 250 requiring only a 15 mass difference between both simultaneous beams. A fully magnetic approach is proposed, made of four dipoles. A first Elbek type dipole distributes the ions along parallel trajectories. A second one of the same type is placed in opposition and ensures for the left way the selection of one of the light masses. A third dipole deflects the heavy masses analysed by the first dipole, preserves their parallel trajectories and provides a reorientation of the beam. A fourth Elbek type dipole ensures for the right way the selection of one of the heavy masses. Optical simulations are performed in a realistic magnetic structure for the four dipole magnets.