NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
MSU, East Lansing, Michigan, USA
Rare isotopes are produced at the NSCL by projectile fragmentation at energies of ~100 MeV/u. The NSCL has successfully used linear gas stopping cells for more than a decade to decelerate projectile fragments to the keV range; first for experiments at low-energy and more recently for reacceleration. A novel reverse-cyclotron has been constructed by the NSCL based on a superconducting sectored-cyclotron magnet and LN2-cooled He gas to confine and slow down the fragments. Efficient stopping is predicted even for light ions that are difficult to thermalize in linear gas cells. The thermalized ions are transported to the center by a radial RF-carpet system, extracted through the yoke with an ion conveyor and accelerated to <60 keV for delivery to users. Measured field profiles have confirmed field calculations. The cryogenic beam-stopping chamber has been installed inside the magnet. The RF ion-guiding components have been tested successfully offline and are being prepared for low-energy ion-transport tests inside the magnet. A summary of the expected performance, the status of the machine, and results from recent low-energy transport tests will be presented.
