Paper | Title | Page |
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TUPLT061 | Production and Transport of Radioactive Francium for Magneto-optical Trapping | 1294 |
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An innovative facility for the production and trapping of francium isotopes is operating at the INFN laboratories in Legnaro, Italy. The goal is to obtain a dense cloud of cold and possibly polarized radioactive atoms for a wide range of fundamental studies. Among them are high-resolution laser spectroscopy, alpha-decay asymmetries from deformed nuclei, and tests of the standard model at low transferred momenta. The production of francium is achieved by sending a 100-MeV oxygen-18 beam from the Tandem-XTU accelerator on a thick gold target. The extraction of Fr+ is enhanced by heating the target to 1200 K and by biasing it at +3 kV. The ions are transported to the magneto-optical trap (MOT) through a 7-m electrostatic beam line. The diagnostic systems for monitoring the beam intensity (105 ions/s) are based on silicon detectors sensitive to the alpha particles from Fr decays. Beams of stable Rb+ can also be used for optimizing the transport and trapping processes. Prior to injection into the MOT the beam is neutralized and released in atomic form by a heated yttrium or zirconium foil. Details on the production, transport and neutralization processes are presented. |