EXCYT: The RIB project at INFN-LNS

Abstract: The EXCYT facility at the INFN-LNS is based on a K-800 superconducting cyclotron, as a driver for stable heavy ion beams (up to 80MeV/amu, 1pμA), and on a 15MV tandem for post-accelerating the radioactive ion beams produced in a target-ion source (TIS) assembly. For some ion beam such as for Li, the higher extraction efficiency from the TIS is obtained by positive ionisation. Then the injection into the tandem is suitable only after a charge exchange (CEC) to obtain negative ions. The production of the radioactive ions were performed by injecting a 13C4+ primary beam of 45MeV/amu on a graphite target up to a beam power of 150W, while the ionisation was achieved by a tungsten positive surface ioniser. The Li+ has been produced at different energies to cross-check the transmission efficiency together with the charge exchange efficiency. The CEC consists of a cell containing Cs vapours which interact with the Li beam converting its charge from +1 to –1 by a two-step reaction; it was already characterized off-line and the results obtained at the EXCYT facility confirm our previous observations and expectations such as the efficiency at the extraction energies and the isotopic shift effect. Hereinafter the results of 8,9Li beams production are reported together with a brief presentation of the facility and with some future improvements and plan. [Copyright &y& Elsevier]