Towards a nuclear charge radius determination for beryllium isotopes

We propose determination of isotope shifts for radioactive beryllium isotopes using laser cooled ions in a linear radio frequency (RF) trap. Based on these measurements, combined with precise mass shift calculations, it will be possible to extract model-independent nuclear charge radii of 7,9,10Be and the one-neutron halo 11Be with precision better than 3%. Radioactive beryllium isotopes produced at ISOLDE and ionized with a laser ion source will be cooled and bunched in the radio frequency quadrupole buncher of ISOLTRAP. Ion temperatures will be reduced to the mK range by sympathetic cooling with co-trapped laser cooled ions in a specially designed two-stage linear RF trap. Resonances will be detected via fluorescence and frequencies measured with a femtosecond frequency comb.