Beam dynamics studies for the reacceleration of low energy ribs at the NSCL

Abstract

Rare Isotope Beams (RIBs) are created at the National Superconducting Cyclotron Laboratory (NSCL) by the in-flight particle fragmentation method. A novel system that stops the RIBs in helium gas and reaccelerates them is proposed to provide opportunities for an experimental program ranging from low energy Coulomb excitation to transfer reaction studies of astrophysical reactions. The beam from the gas stopper [1] will first be brought into a Electron Beam Ion Trap (EBIT) charge breeder [2] on a high voltage platform to increase its charge state, and then accelerated up to about 3 MeV/u by a system consisting of an external multi-harmonic buncher and a radio frequency quadrupole (RFQ) followed by a superconducting linac. The superconducting linac will use quarter-wave resonators with optimum acceleration for particle velocities as a fraction of the speed of light (betaopt) of 0.041 and 0.085 for acceleration and superconducting solenoid magnets for transverse focusing. The accelerator system design and the end-to-end beam dynamics simulations are presented.