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The Extreme Light Infrastructure-Nuclear Physics (ELI-NP) facility, under construction in Magurele near Bucharest in Romania, will provide high-intensity and high-resolution gamma ray beams that can be used to address hotly debated problems in nuclear astrophysics, such as the accurate measurements of the cross sections of the 24Mg(γ,α)20Ne reaction, that is fundamental to determine the effective rate of 28Si destruction right before the core collapse and the subsequent supernova explosion. For this purpose, a silicon strip detector array (named ELISSA, acronym for Extreme Light Infrastructure Silicon Strip Array) will be realized in a common effort by ELI-NP and Laboratori Nazionali del Sud (INFN-LNS), in order to measure excitation functions and angular distributions over a wide energy and angular range. A prototype of ELISSA was built and tested at INFN-LNS in Catania (Italy) with the support of ELI-NP. In this occasion, we have carried out experiments with alpha sources and with a 11 MeV 7Li beam. Thanks to our approach, the first results of those tests show up a very good energy resolution (better than 1%) and very good position resolution, of the order of 1 mm. Moreover, a threshold of 150 keV can be easily achieved with no cooling. [ABSTRACT FROM AUTHOR]

The astrophysical p-process is an important way of nucleosynthesis to produce the stable and proton-rich nuclei beyond Fe which can not be reached by the s- and r-processes. In the present study, the astrophysical reaction rates of (γ, n), (γ, p), and (γ, α) reactions are computed within the modern reaction code TALYS for about 3000 stable and proton-rich nuclei with 12 < Z < 110. The nuclear structure ingredients involved in the calculation are determined from experimental data whenever available and, if not, from global microscopic nuclear models. In particular, both of the Wood-Saxon potential and the double folding potential with density dependent M3Y (DDM3Y) effective interaction are used for the calculations. It is found that the photonuclear reaction rates are very sensitive to the nuclear potential, and the better determination of nuclear potential would be important to reduce the uncertainties of reaction rates. Meanwhile, the Extreme Light Infrastructure-Nuclear Physics (ELI-NP) facility is being developed, which will provide the great opportunity to experimentally study the photonuclear reactions in p-process. Simulations of the experimental setup for the measurements of the photonuclear reactions 96Ru(γ, p) and 96Ru(γ, α) are performed. It is shown that the experiments of photonuclear reactions in p-process based on ELI-NP are quite promising. [ABSTRACT FROM AUTHOR]

The investigation of neutron-rich exotic nuclei is crucial not only for nuclear physics but also for nuclear astrophysics. Experimentally, only few neutron-rich nuclei near the stability have been studied, however, most neutron-rich nuclei have not been measured due to their small production cross sections as well as short half-lives. At ELI-NP, gamma beams with high intensities will open new opportunities to investigate very neutron-rich fragments produced by photofission of 238U targets in a gas cell. Based on some simulations, a novel gas cell has been designed to produce, stop and extract 238U photofission fragments. The extraction time and efficiency of photofission fragments have been optimized by using SIMION simulations. According to these simulations, a high extraction efficiency and a short extraction time can be achieved for 238U photofission fragments in the gas cell, which will allow one to measure very neutron-rich fragments with short half-lives by using the IGISOL facility proposed at ELI-NP. [ABSTRACT FROM AUTHOR]

The neutron orbitals h11/2, d3/2, s1/2, determine the structure of the abundant yrast traps in the neutron-rich Sn isotopes close to 132Sn. In 125,127,129Sn the high-spin members of the v(d3/2-1h11/2-2) and v(h11/2-n), seniority v = 3, multiplets form isomeric (23/2+) [1,2] and (27/2-) [2] states which were recently observed in relativistic fission of 238U and fragmentation of 136Xe at the RISING setup at GSI. These rather pure states and the mixed 19/2+ isomers with a dominant v(s1/2-1h11/2-2) configuration [3] are discussed. First evidence for a new isomer in 128Sn with v(d3/2-1h11/2-3) configuration analogue to the isotone 130Te [4] is presented. [ABSTRACT FROM AUTHOR]

Recent studies of the properties of “shears” states and magnetic rotational bands in the Pb nuclei are reviewed and discussed in the light of the systematic occurrence of such excitations in this mass region. In particular, the νi13/2-1xπ(h9/2i13/2)11- band in 193Pb is discussed, where a full set of experimental observables have been obtained: the lifetime, the spin-parity, the g factor and the quadrupole moment of the band head, as well as the intensities and the lifetimes within the band. These, combined with the measured g factors and quadrupole moments of the “blades of the shears” allow a stringent test of the theoretical models aiming at the description of such excitations in atomic nuclei. The occurrence of triaxial deformations in the mass A ≈ 190 Ir-Pt nuclei is discussed and recent spectroscopic results are presented. A possible assignment of a twin band in 188Ir is discussed in light of chiral rotation. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]