Precision laser and microwave spectroscopy of radioactive Be isotopes provided from a projectile fragment separator RIPS

Radioactive Be isotope beams from RIKEN RIPS at approximately 1 GeV were thermalized in an RF ion guide gas cell and extracted by a combination of DC and inhomogeneous RF electric fields. The extracted ions were transported via a carbon-OPIG to a linear RF trap located in UHV environment. They were further cooled down to 10$^{-6}$~eV by laser cooling for precision atomic spectroscopy. The ground state hyperfine splitting of $^7$Be and $^{11}$Be were measured directly with accuracies of 10$^{-7}$ by microwave-laser double resonance method. The optical transition frequencies for 2$s_{1/2}$-2$p_{3/2}$ transition of $^7$Be, $^9$Be, $^{10}$Be, and $^{11}$Be ions were also measured with accuracies of 10$^{-9}$ by laser-laser double resonance method. These experiments aim to independently measure the nuclear charge and magnetization radii by the isotope shift and the Bohr-Weisskpf effect, respectively, especially for one neutron halo nucleus $^{11}$Be. We discuss the RF-carpet ion guide technique and the results of spectroscopy experiments.