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We review the present and future of trap-assisted structure studies of odd, neutron-rich Tc, Ru, Rh and Pd isotopes at the limits of present experimental techniques. These nuclei of refractory elements are produced in light-particle induced fission and filtered by their mass number with the IGISOL mass separator. Further mass separation with the JYFLTRAP Penning trap system provides a clean, monoisotopic beam perfectly suited for precise nuclear spectroscopy. Connecting the IGISOL and the JYFLTRAP facilities to the recently installed MCC30/15 cyclotron opens new prospects for post-trap spectroscopy of very exotic, neutron-rich nuclei. [ABSTRACT FROM AUTHOR]

The consistent model for the description of the independent fission product formation cross-section at light projectile energies up to about 100MeV is described. Pre-compound nucleon emission is described in the framework of the two-component exciton model using the Monte Carlo method, which allows one to incorporate a time duration criterion for the pre-equilibrium stage of the reaction. The decay of the excited compound nuclei, formed after the pre-equilibrium neutron and proton emission, is treated within the time-dependent statistical model with the inclusion of the main dynamical effects of nuclear friction on the fission width and saddle-to-scission descent time. For each member of the compound nucleus ensemble at scission point, the primary fragment isobaric chain yields are calculated using the multimodal approach with the inclusion two superasymmetric fission modes. The charge distribution of the primary fragment isobaric chains was considered as a results of frozen quantal fluctuations of the isovector nuclear matter density at the finite scission neck radius. The calculated fission product formation cross-sections in the neutron, proton, and $ \gamma$ -rays induced fission of the heavy actinides are presented. [ABSTRACT FROM AUTHOR]

Penning-trap measurements on stable Mo isotopes have been performed with relative accuracy of $\ensuremath 1\cdot 10^{-8}$ with the JYFLTRAP Penning-trap mass spectrometer by using Rb as a reference. The Mo isotopes have been found to be about 3keV more bound than given in the Atomic Mass Evaluation 2003 (AME03). The results confirm that the discrepancy between the ISOLTRAP and JYFLTRAP data for Cd isotopes was due to an erroneous value in the AME03 for Mo used as a reference at JYFLTRAP. The measured frequency ratios of Mo isotopes have been used to update mass-excess values of 30 neutron-deficient nuclides measured at JYFLTRAP. [ABSTRACT FROM AUTHOR]

The Penning trap mass spectrometer JYFLTRAP, coupled to the Ion Guide Isotope Separator On-Line (IGISOL) facility at Jyväskylä, was employed to measure the atomic masses of neutron-rich 70-73Ni and 73, 75Cu isotopes with a typical accuracy less than 5keV. The mass of 73Ni was measured for the first time. Comparisons with the previous data are discussed. Two-neutron separation energies show a weak subshell closure at 68 28Ni40 . A well established proton shell gap is observed at Z = 28 . [ABSTRACT FROM AUTHOR]

Exotic, neutron-rich 111Mo and 115Ru nuclei, produced in proton-induced fission of 238U target, were separated with the IGISOL mass separator. The separator was coupled to the JYFLTRAP Penning trap to select the ions of a single, desired element out of the isobaric IGISOL beam. Monoisotopic samples of 115Ru and 111Mo ions were observed with a microchannel plate detector after the trap or were implanted on a catcher foil for gamma- and beta-ray coincidence spectroscopy. In spite of short data taking time new gamma transitions were identified in the beta decay of very neutron-rich 115Ru. [ABSTRACT FROM AUTHOR]

Decay properties of neutron-deficient exotic nuclei close to A=80 have been investigated at the IGISOL facility. The studied nuclei, 81Y, 81Sr, 81mKr, 85Nb, 85Zr, 86Mo and 86Nb, were produced by a 32S beam from the Jyväskylä isochronous cyclotron on 54Fe and natNi targets. The internal conversion coefficient for a 190.5 keV isomeric transition in 81mKr has been measured and the internal transition rate has been determined. The internal transition rate has been used to estimate a neutrino capture rate on 81Br, which yields a log ft of 5.13±0.09 for the reaction 81Br( ν, e-)81mKr. A new isomer with a half-life of 3.3±0.9 s has been observed in 85Nb. The existence of an earlier reported isomer with a half-life of 56 s in 86Nb has not been confirmed. [ABSTRACT FROM AUTHOR]

The β-decay properties of the neutron-deficient nuclei 25Si and 26P have been investigated at the GANIL/LISE3 facility by means of charged-particle and γ-ray spectroscopy. The decay schemes obtained and the Gamow­Teller strength distributions are compared to shell-model calculations based on the USD interaction. B(GT) values derived from the absolute measurement of the β-decay branching ratios give rise to a quenching factor of the Gamow­Teller strength of 0.6. A precise half-life of 43.7 (6) ms was determined for 26P, the β-(2)p decay mode of which is described. [ABSTRACT FROM AUTHOR]

The theoretical model for calculations of the fission product yields in the light-particle induced fission is discussed. A comparison of the production cross sections in fission of 238U by protons, thermal and fast neutrons, and photons is presented. The results of studies of the very asymmetric fission of 238U by protons and neutron at the moderate energy are reported. [Copyright &y& Elsevier]

It was shown for the first time that quasi- and deep-inelastic reactions can be successfully incorporated into the conventional Ion-Guide Isotope Separator On-Line (IGISOL) technique. Yields of radioactive projectile-like species such as 62, 63Co are about 0.8ions/s/pnA corresponding to a total IGISOL efficiency of about 0.06%. [ABSTRACT FROM AUTHOR]

The new Decay Total Absorption Spectrometer (DTAS) has been commissioned with low energy radioactive beams at the upgraded IGISOL IV facility. The DTAS is a segmented detector composed of up to 18 NaI(Tl) crystals and it will be a key instrument in the DESPEC experiment at FAIR. In this document we report on the experimental setup and the first measurements performed with DTAS at IGISOL. The detector was characterized by means of MC simulations, and this allowed us to calculate the response function of the spectrometer and analyse the first cases of interest. [ABSTRACT FROM AUTHOR]

Atomic masses of the neutron-rich isotopes 121-128Cd, 129,131In, 130-135Sn, 131-136Sb, and l32-140Te have been measured with high precision (10 ppb) using the Penning-trap mass spectrometer JYFLTRAP. Among these, the masses of four r-process nuclei 135Sn, l36Sb, and 139,140Te were measured for the first time. An empirical neutron pairing gap expressed as the odd-even staggering of isotopie masses shows a strong quenching across N = 82 for Sn, with a Z dependence that is unexplainable by the current theoretical models. [ABSTRACT FROM AUTHOR]

Abstract: The atomic masses of neutron-rich 95–101Y and 101–107Nb produced in proton-induced fission of uranium were determined using the JYFLTRAP double Penning trap setup. Accuracies of better than 10 keV could be reached for most nuclides. The masses of 106,107Nb were measured for the first time. The energies of the isomeric states in 96Y and 100Y were measured as 1541(10) keV and 145(15) keV. The niobium isotopes appear to be systematically less bound than the values given in the latest Atomic Mass Evaluation. The new data lie in a region of the nuclear chart characterised by the transition from spherical to strongly deformed shapes. These structural changes are explored by studying different systematic trends. The data are also compared to several model predictions to test their ability to reproduce the structural changes along the isotopic chains of yttrium and niobium. [Copyright &y& Elsevier]

The production of neutron-deficient krypton isotopes having astrophysical importance has been studied at the ISOLDE PBS facility at CERN. To investigate several effects on the yield a Monte Carlo code has been extensively applied. [Copyright &y& Elsevier]

Rapid shape evolutions near A=100 are now the focus of much attention in nuclear science. Much of the recent work has been centered on isotopes with Z≤40, where the shapes are observed to transition between near-spherical to highly deformed with only a single pair of neutrons added. At higher Z, the shape transitions become more gradual as triaxiality sets in, yet the coexistence of varying shapes continues to play an important role in the low-energy nuclear structure, particularly in the odd-Z isotopes. This work aims to characterize competing shapes in the triaxial region between Zr and Sn isotopes using ultrafast timing techniques to measure lifetimes of excited states in the neutron-rich nucleus 109Rh. The measurements confirm the persistence at higher Z of similarly large deformations observed near Z=40. Moreover, we show that new self-consistent mean-field calculations, with proper treatment of the odd nucleon, are able to reproduce the coexisting triaxial and highly deformed configurations revealing, for the first time, the important contribution of the unpaired nucleon to these different shapes based on the blocking of specific single-particle orbitals. [ABSTRACT FROM AUTHOR]