The laser ion source project at the IGISOL facility, Jyväskylä, has motivated the development and construction of an rf sextupole ion beam guide (SPIG) to replace the original skimmer electrode. The SPIG has been tested both off-line and on-line in protoninduced fission, light-ion and heavy-ion induced fusion-evaporation reactions and, in each case, has been directly compared to the skimmer system. For both fission and light-ion induced fusion, the SPIG has improved the mass-separated ion yields by a factor of typically 4 to 8. Correspondingly, the transmission efficiency of both systems has been studied in simulations with and without space charge effects. The transport capacity of the SPIG has been experimentally determined to be ∼10 12 ions s −1 before space charge effects start to take effect. A direct comparison with the simulation has been made using data obtained via light-ion fusion evaporation. Both experiment and simulation show an encouraging agreement as a function of current extracted from the ion guide.

The masses of very neutron-deficient nuclides close to the astrophysical rp-and νp-process paths have been determined with the Penning trap facilities JYFLTRAP at JYFL/Jyväskylä and SHIP-TRAP at GSI/Darmstadt. Isotopes from yttrium (Z = 39) to palladium (Z = 46) have been produced in heavy-ion fusion-evaporation reactions. In total 21 nuclides were studied and almost half of the mass values were experimentally determined for the first time:88 Tc,

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The feeding probability of 102;104;105;106;107 Tc, 105 Mo, and 101 Nb nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the component of the decay heat for 239 Pu in the 4-3000 s range. DOI: 10.1103/PhysRevLett.105.202501 PACS numbers: 23.40.Às, 27.60.+j, 28.41.Fr, 29.30.Kv Nuclear reactors provide a significant fraction of the world's electricity. A burgeoning population and an associated growth in economic activity suggest that world demand will double by 2050. Until now, the bulk of this has come from the burning of fossil fuels. There is general concern that reserves of fossil fuels are limited and their burning damages the environment. In particular, it contributes to the emission of large amounts of CO 2 . In this context, nuclear power, based on the fission process, will be less damaging to the environment. Accordingly there is now a renaissance in the building of nuclear power stations around the world. Modern reactor designs, based on many years of operating experience, are much more efficient, more economical, and safer than earlier designs. Although the basic principles are well established, we still lack certain information, such as a knowledge of the decay properties of specific nuclei that are important contributors to the heating of the reactor during and after operation. The estimation and control of the heat emitted by the decay of fission products plays a key role in the safe operation of reactors. The primary aim of this work is to study the decay properties of specific nuclei that are important contributors to this source of heat.Approximately 8% of the total energy generated during the fission process is related to the energy released in the natural decay of fission products, and is commonly called decay heat [1]. Once the reactor is shut down, the energy released in radioactive decay provides the main source of heating. Hence, coolant needs to be maintained after termination of the neutron-induced fission process in a reactor, and the form and extent of this essential requirement needs to be specified on the basis of decay-heat summation calculations. Decay heat varies as a function of time after shutdown and can be determined theoretically from known nuclear data. Such computations are based on the inventory of nuclei created during the fission process and after reactor shutdown and their radioactive decay characteristics:where fðtÞ is the power function, E i is the mean decay energy of the ith nuclide ( , , and components), i is the decay constant of the ith nuclide, and N i ðtÞ is the number of nuclide i at cooling time t. These calculations require extensive libraries of cross sections, fission yields, and decay data. Obviously, an accurate assessment of the decay heat is highly relevant...

In-gas-cell laser spectroscopy study of the 57,59,63,65 Cu isotopes has been performed for the first time using the 244.164 nm optical transition from the atomic ground state of copper. The nuclear magnetic dipole moments for 57,59,65 Cu relative to that of 63 Cu have been extracted. The new value for 57 Cu of µ( 57 Cu) = +2.582(7)µN is in strong disagreement with the previous literature value but in good agreement with recent theoretical and systematic predictions.PACS numbers: 21.10. Ky, 27.40.+z, 27.50.+e, 42.62.Fi With more than 3000 nuclei known so far, the present nuclear chart offers a vast landscape to study mesoscopic systems. Many of these nuclei cannot be described by ab initio calculations and theory uses models based on a fundamental or phenomenological approach in order to describe observables of isotopes yet to discover. The confrontation of experimental data with the theoretical predictions does not only allow for fine tuning of theory but also for discovering new aspects of the interactions at work in the atomic nucleus. This is especially the case when studying isotopes with extreme proton-toneutron ratios. In nuclear structure, the identification of the magic numbers 2, 8, 20, 28, 50, 82, 126 [1] is the foundation for the shell model of the nucleus. While these magic numbers are well established in nuclei close to the valley of β-stability, their universality is strongly questioned [2].Of special interest is the magic number 28 as it is the smallest magic number issued from the spin-orbit interaction added to the nuclear potential. Both the N = 28 isotones [3,4] and the nickel (Z = 28) isotopes [5,6] are under intensive investigation to probe their magic character. With N = Z = 28, 56 Ni is expected to be doubly magic. While it displays a high 2 + 1 excited state in comparison to the other nickel isotopes [5] and a sudden change in the two-neutron and two-proton separation energies [7], both characteristic of a doubly magic nucleus, the evolution of the transition strength B(E2) and the behavior of the nuclei in the vicinity point towards particle excitations across the shell gaps and a breaking of this magic core [8,9,10].The nuclear magnetic dipole moment is a very sensitive tool to study the nuclear structure in the vicinity of magic nuclei.

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