EURICA Workshop

Status report of the EURICA project.

The proposal deals with study of doubly - magic 100Sn and neighboring nuclei via measurement of their beta- and isomeric-decay. Very high production rates, which should be achievable at the RIBF/BigRIPS facility for nuclei in the vicinity of 100Sn together with the EURICA Germanium setup, open new possibilities for the decay spectroscopy. The main goals of the experiment are: measurement of...

Recent work at GSI has enabled us to obtain evidence for the 16+ spin-gap isomer in 96Cd via its beta decay to the 15+ isomeric state in 96Cd. However, large scale shell model calculations using the gds model space indicate that the state should also undergo beta-delayed proton decay. Our previous data did not have sufficient statistics to enable us to search for such decays. It is...

We have studied the Tz = -1 -> 0 beta decays of 42Ti, 46Cr, 50Fe and 54Ni to the self-conjugate nuclei 42Sc, 46V, 50Mn, and 54Co respectively (Ph.D Thesis, Francisco Molina- Uni. Valencia) at GSI during the stopped beam RISING campaign. The nuclei of interest were produced in the fragmentation of a 58Ni beam at 680 MeV/nucleon. The number of implanted ions of the nucleus of interest was...

It is well known that in the atomic nucleus, alike nucleons (neutrons or protons) in time reverse orbits, couple in pairs giving rise to nuclear superfluidity, with very significant impact in the structure as well as in the collective properties of the nucleus. In addition, nuclei consist of a combination of two fermionic fluids (neutrons and protons) and as a consequence of the isospin (T)...

An experiment based on gamma-decay of isomer state in neutron-rich 77Ni produced from fragmentation of a 238U beam is proposed in order to reveal the neutron single particle energies associated with the N=40 and N=50 shell closures. Based on the lifetime of the 1/2- isomeric state in 77Ni an estimate or at least a lower limit on the energy of the 2+ state in 78Ni can be deduced. Energy and...

RIBF can produce very neutron rich nuclei in the A=90-110 region with unprecedented intensities. The structural evolution in this mass region is particularly rich since substantial energy gaps between various deformation driving Nilsson orbitals exist and configurations of different shape compete at low excitation energies. At the same time the properties of these nuclei are relevant for...

Recent data on Ge and Se isotopes above the N=50 shell closure has led to the discussion of a weakening of the Z=28 proton shell, based on relatively low first excited 2+ energies in the N=52 Ge and Se isotones. Further discussion relates to the possible emergence of a new neutron sub-shell closure at N=58, based on the evolution of single particle energies in N=51 isotones. Both effects would...

In the region of the neutron rich iron isotopes, around the r-process starting point, only few spectroscopic information is available. We aim to determine life times, beta and isomeric decays and built first level schemes in 70-72Fe and around. We plan to use the unique combination of the high beam intensities available at RIKEN together with BigRIPS-ZeroDegree spectrometer and the EURICA and...

Study of doubly-closed-shell and neighboring nuclei provides great opportunities for testing of nuclear models and expanding our knowledge of nucleosynthesis processes. Especially, the region around 78Ni (Z=28, N=50) has attracted great interests because of its extreme neutron-to-proton ratio in the region far from the valley of stability. Despite of a great deal of theoretical activity...

We propose to investigate the beta decay of the neutron rich N=52 nucleus 81Cu for EURICA campaign, in order to observe for the first time the low lying excited states in the N=51 isotone 81Zn. N=51 odd isotones constitute the best cases to study the neutron single particle effective energy evolution towards 78Ni. The study of 81Zn level sequence will provide critical data to predict the...

Neutron-rich zirconium (Z=40) nuclei lie in the midst of a shape-changing region with many models predicting a transition from spherical to prolate/oblate coexistence at N~60. Measurements of the mean-square charge radii in the zirconium chain [Ca02] indicate a shape transition at N=59. In order to further investigate the low-lying structure of more-exotic systems, an experiment was...

Symmetry of tetrahedral shape generates a different degeneracy in single particle levels from the quadrupole deformed shape. The stability of the tetrahedral shape is not established in the atomic nuclei. Neutron-rich nucleus 110Zr, which has the doubly magic numbers of tetrahedral shape, Z = 40 and N = 70, is one of the candidates to search for the tetrahedral shape. Recently, we discovered...

The b-decay study of the region around the N=82 shell closure is critical for r-process models. With this experiment we intend to study the decay of the N=82 nuclei 128Pd and 129Ag that are expected to be waiting points for the the r-process in most r-process models, and therefore their study will dramatically improve the reliability of the r-process calculations. New half-lives will also be...

The r-process overabundance in the mass region A~120 has been a subject of considerable scientific interest in the last decade. Different nuclear physics phenomena such as shell-quenching and "unreasonably" long beta-decay half-lives were discussed as possible reasons for the observed discrepancy. Long-lived activities are known to exist throughout a number of odd-Z, even-N and...

Experiments to study excited levels in neutron-rich Z~60 isotopes through isomer spectroscopy will be discussed.