Laser source of radioactive ion beams at the on-line isotope separation facility ISOLDE at CERN

by Dr Valentin Fedosseev (CERN)

Tuesday 13 Dec 2011, 14:30 → 15:30 Europe/Rome

Direction meeting room (INFN-LNL)

The Resonance Ionization Laser Ion Source (RILIS) of the ISOLDE on-line isotope separation facility is based on the method of laser step-wise resonance ionization of atoms in a hot metal cavity. The atomic selectivity of the RILIS compliments the mass selection process of the ISOLDE separator magnets to provide beams of a chosen isotope with greatly reduced isobaric contamination. RILIS achieves efficient ionization for many elements through the selection of suitable atomic transitions which are excited by high average power dye lasers. Currently, a 10 kHz pulse rate Nd:YAG laser emitting 532 nm and 355 nm beams with total power of 100 W is being used for pumping the dye lasers. Recently a fully solid state laser system based on Ti:Sapphire lasers has been built at CERN to compliment the dye laser system. To date, ion beams of 31 different elements have been produced at ISOLDE with RILIS. Combining laser wavelength scanning over a resonance transition of RILIS excitation scheme with the detection of short-lived isotopes by methods of nuclear spectroscopy has enabled very sensitive atomic spectroscopy studies of isotopes far from stability. This experimental technique called “In-source spectroscopy” has been applied for isotope shifts and hyperfine structure measurements of Cu, Tl, Pb, Bi, Po, as well as for first measurement of the ionization potential of the astatine atom.