A novel scheme for injection and stacking of radioactive ions at high energy

In the so-called “beta-beam” route to accelerator-driven neutrino experiments, it is proposed to accumulate radioactive ions at high energy in a large decay ring. Stacking is essential to reach the intensities required, but none of the established beam cooling methods can be applied to counter the inflation of beam emittance with the addition of each fresh shot. A new stacking scheme which exploits the fact that the ions are radioactive is proposed to prevent a runaway growth of emittance.