Cross section measurements of the 3He(alpha, gamma) 7Be reaction using DRAGON at TRIUMF.

4 pags., 2 figs. -- Nuclear Physics in Astrophysics V 3–8 April 2011, Eilat, IsraelWe present our initial efforts with the DRAGON separator at TRIUMF facility towards obtaining the energy dependence of the astrophysical S-factor for 3He(¿, ¿)7Be reaction in the energy range of Ecm = 2 to 3 MeV that was recommended by the recent evaluations. A comparison between the existing data and our new complementary Madrid data, together with the recent theoretical calculations, is also given in the context of our ongoing work.This work has been supported by the UK STFC

Broken seniority symmetry in the semimagic proton mid-shell nucleus ⁹⁵Rh

Lifetime measurements of low-lying excited states in the semimagic ( N = 50 ) nucleus 95Rh have been performed by means of the fast-timing technique. The experiment was carried out using γ -ray detector arrays consisting of LaBr3(Ce) scintillators and germanium detectors integrated into the DESPEC experimental setup commissioned for the Facility for Antiproton and Ion Research (FAIR) Phase-0, Darmstadt, Germany. The excited states in 95Rh were populated primarily via the β decays of 95Pd nuclei, produced in the projectile fragmentation of a 850 MeV/nucleon 124Xe beam impinging on a 4 g / cm2 9Be target. The deduced electromagnetic E2 transition strengths for the γ -ray cascade within the multiplet structure depopulating from the isomeric Iπ = 21 / 2+ state are found to exhibit strong deviations from predictions of standard shell model calculations which feature approximately conserved seniority symmetry. In particular, the observation of a strongly suppressed E2 strength for the 13 / 2+ → 9 / 2+ ground state transition cannot be explained by calculations employing standard interactions. This remarkable result may require revision of the nucleon-nucleon interactions employed in state-of-the-art theoretical model calculations, and might also point to the need for including three-body forces in the Hamiltonian

The shape of the <i>T</i>_z = +1 nucleus ⁹⁴Pd and the role of proton-neutron interactions on the structure of its excited states

Reduced transition probabilities have been extracted between excited, yrast states in the N = Z + 2 nucleus 94Pd. The transitions of interest were observed following decays of the Iπ = 14+ , Ex = 2129-keV isomeric state, which was populated following the projectile fragmentation of a 124Xe primary beam at the GSI Helmholtzzentrum für Schwerionenforschung accelerator facility as part of FAIR Phase-0. Experimental information regarding the reduced E2 transition strengths for the decays of the yrast 8+ and 6+ states was determined following isomer-delayed Eγ1 − Eγ2 − △T2,1 coincidence method, using the LaBr3(Ce)-based FATIMA fast-timing coincidence gamma-ray array, which allowed direct determination of lifetimes of states in 94Pd using the Generalized Centroid Difference (GCD) method. The experimental value for the half-life of the yrast 8+ state of 755(106) ps results in a reduced transition probability of B(E2:8+ →6+ ) = 205+34 −25 e2fm4 , which enables a precise verification of shell-model calculations for this unique system, lying directly between the N = Z line and the N = 50 neutron shell closure. The determined B(E2) value provides an insight into the purity of (g9/2)n configurations in competition with admixtures from excitations between the (lower) N = 3 pf and (higher) N = 4 gds orbitals for the first time. The results indicate weak collectivity expected for near-zero quadrupole deformation and an increasing importance of the T = 0 proton-neutron interaction at N = 48

Band structures in 108^{108}In

High spin states in $^{108}$In have been established upto ~ 8 MeV in excitation energy and to a tentative spin of (23$^-$). The data were obtained by in-beam $\gamma$-ray spectroscopy using the reaction at a beam energy of 86 MeV. Four sequences of dipole bands and a normal rotational band of E2 $\gamma$-transitions have been placed in the level scheme

Experimental study of lifetimes of excited states in the K^π= 0^-octupole band and γ-vibrational band in ²²⁸Th

Lifetimes of excited states in the Kπ = 0- octupole band and γ-vibrational of 228Th have been measured using the fast timing setup at the University of the West of Scotland (UWS). The setup consists of two cerium doped LaBr3 fast scintillators placed equidistant from the radioactive source 232Th. The states of interest have been analysed by doing the triple γ - γ - time coincidence analysis and using the fast-timing technique, mirror-symmetric centroid difference method. Octupole collectivity in 228Th nucleus is also investigated by calculating the enhanced electric dipole moments and transition rates in excited states followed by lifetime measurements in octupole band

He-3(alpha, gamma) Be-7 cross section measured using complementary techniques.

INPC 2013 – International Nuclear Physics Conference; 4 pags.; 3 figs.; Open Access funded by Creative Commons Atribution Licence 2.0The astrophysical S-factor for the 3He(α,γ)7Be reaction plays an important role in the Solar Standard Model and in the Big Bang Nucleosynthesis scenario. The advances from two recent experiments performed using complementary techniques at center of mass (C.M.) energies between 1 and 3 MeV are discussed.The work was partly financed by the Spanish Research Funding Agency CICYT under Project FPA2012-32443 and was supported by the UK STFC. Further M.C.G. acknowledges his CSICJAEpredoc grant partly funded by the European Social Funds.Peer Reviewe

3He(α,γ)7Be cross section measured using complementary techniques

The astrophysical S-factor for the 3He(α,γ)7Be reaction plays an important role in the Solar Standard Model and in the Big Bang Nucleosynthesis scenario. The advances from two recent experiments performed using complementary techniques at center of mass (C.M.) energies between 1 and 3 MeV are discussed

New measurement of the 3He(α,γ)7Be cross section at medium energies

We report on a new cross-section measurement for the 3He(α, γ)7Be reaction at three medium energies of E c.m. between 1 and 3 MeV. The interest stems from the significant role played by the reaction in calculating an accurate solar neutrino flux and the primordial 7Li abundance. The energy dependence of the astrophysical S 34 factor observed in the present work, especially above 1 MeV, highlights the need to constrain theories in order to obtain a precise extrapolated value for S 34(0). In this context, a comparison with the recent theoretical work in a fully microscopic fermionic molecular dynamics approach and a few other representative calculations emphasize the need for further experimental as well as theoretical work to resolve the existing conflicts. ©2012 American Physical Society.Supported by the UK STFC and was partly financed by the Spanish Research Funding Agency CICYT under Project FPA2009-07387. Further, M.C.G. acknowledges his CSIC-JAEpredoc grant partly funded by the European Social Funds.Peer Reviewe