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Optical isotope shifts and hyperfine structures of the147–153,155,157,159 Tb isotopes have been measured by the resonance ionization spectroscopy method. Nuclear moments and changes in nuclear charge radii? 2> have been deduced. The “jump” in? 2> atN=88–90 has been revealed. It is compared with the relevant data for nuclei with other proton numbers.

A highly sensitive method of detecting atoms in samples has been used for spectral investigations of the rare radioactive element Fr. The method is based on laser-resonance photoionization of Fr atoms in a hot quasi-enclosed cavity. The investigations have been carried out with samples in which short-lived radioactive ^221Fr atoms formed at a rate of approximately 10^3 atoms/sec. The data obtained, to our knowledge for the first time, on the energies of the high-lying Rydberg levels of the ^2S_1/2 and ^2D series have made it possible to determine the electron binding energy of the 7p^2P_3/2 state and to establish the ionization potential of Fr accurately.

Production of intensive (up to 1 mA) ionic beams through stepwise photoionization of atoms induced by laser radiation is investigated. Optimum photoionization schemes are presented. A photoionic gallium beam is obtained with an average current value of 2.5 µA.

Detection of single atoms Yb has been achieved using the method of electric-field ionization from the high-lying Rydberg states. Atoms of Yb in a beam were excited in three steps to a 17-p state by radiation of three pulsed dye lasers. The statistics of an atom’s appearance in the interaction volume have been studied in the single-ion-counting regime at low beam density.

Nuclear magnetic dipole and electric quadrupole moments and changes in mean square charge radii for the neutron-rich155–159Eu isotopes have been measured using resonance ionization spectroscopy at the IRIS facility. It has been found that the isotopes withN>92, unlike the isotopes with 89?N?92, have an ordinary character of odd-even staggering in nuclear charge radii. This means that the octupole deformation attributed previously to the europium nuclei around154Eu does not display itself in the charge radii of heavier europium isotopes.

A chemically selective laser ion source based on resonance ionization of atoms in a hot cavity has been applied for the study of short-lived silver isotopes at CERN/ ISOLDE. Silver atoms were ionized by two resonant excitations and final laser ionization into the continuum. Decay properties of the neutron-rich isotopes121–127Ag were studied with a neutron long-counter and aß-detector.

Beta delayed charged particles from 14Be have been measured and give an upper limit on beta delayed alpha particles of B(βα) ≪ 6.7 × 10-5 and a tentative branching ratio on beta delayed tritons of 7.5 ×10-5 ≪ B(βt) ≪ 3.9 ×10-4. We combine the knowledge on beta delayed particles from 14Be to deduce information on the beta strength distribution.