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

Influence of orbital pair breaking on paramagnetically limited states in clean superconductors

Paramagnetic pair breaking is believed to be of increasing importance in many layered superconducting materials such as cuprates and organic compounds. Recently, strong evidence for a phase transition to the Fulde-Ferrell-Larkin-Ovchinnikov(FFLO) state has been obtained for the first time. We present a new theory of competing spin and orbital pair breaking in clean superconducting films or layers. As a general result, we find that the influence of orbital pair breaking on the paramagnetically limited phase boundary is rather strong, and its neglect seldom justified. This is particularly true for the FFLO state which can be destroyed by a very small orbital contribution. We discuss the situation in YBa_2Cu_3O_7 which has two coupled conducting Cu-O layers per unit cell. As a consequence, an intrinsic orbital pair breaking component might exist even for applied field exactly parallel to the layers.Comment: 19 pages, 5 figures, submitted to PR

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

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

Precision measurement of the decay rate of 7Be^7Be in host materials

A controlled and precise determination of the cross sections of the fusion reactions 7Be(p,gamma)8B and 3He(4He,gamma)7Be, which play an important role in determining the solar neutrino flux, necessitates the knowledge of a precise value of the electron-capture half-life of 7Be. This half-life may depend on the material hosting the 7Be atoms via small modifications of the electron density around the 7Be nucleus. In this brief communication we report on the measurement of 7Be implanted in four materials: copper, aluminum, sapphire, and PVC. The four results are consistent with a null host dependence within two standard deviations and their weighted average of 53.236(39) d agrees very well with the adopted value in the literature, 53.22(6) d. The present results may exhibit a slight (0.22%) increase of the half-life at room temperature for metals compared to insulators that requires further studies

Beam suppression of the DRAGON recoil separator for He-3(alpha,gamma)Be-7

Preliminary studies in preparation for an absolute cross-section measurement of the radiative capture reaction 3He(α,γ)7Be with the DRAGON recoil separator have demonstrated beam suppression >1014 at the 90% confidence level. A measurement of this cross section by observation of 7Be recoils at the focal plane of the separator should be virtually background free. & 2012 Elsevier B.V.Peer Reviewe

Magnetic moment of 43m^{43m}S

Expérience GANILInternational audienceThe gyromagnetic factor of the isomeric state of 43S has been measured using the Time Dependent Perturbed Angular Distribution (TDPAD) technique. The isomer was produced and spin aligned via the fragmentation of a 60 AMeV 48Ca beam at the GANIL facility. The deduced magnetic moment confirms the 7/2− spin/parity of the isomeric state and shows, for the first time, the intruder nature of the ground state. Comparison of the experimental values with Shell Model and mean-field based calculations were performed revealing a pronounced ground state deformation and a quasi-spherical isomeric state. A new isomeric state has been observed in the 42P

Shell erosion and shape coexistence in 43 16S27

Expérience GANIL, Spectrométre LISE-2000We report on the g-factor measurement of the first isomeric state in 4316S27 [Ex = 320.5(5) keV, T1/2 = 415(5) ns, and g = 0:317(4)]. The 7/2- spin-parity of the isomer and the intruder nature of the ground state of the nucleus are experimentally established for the first time, providing direct and unambiguous evidence of the collapse of the N = 28 shell closure in neutron-rich nuclei. The shell model, beyond the mean-field and semiempirical calculations, provides a very consistent description of this nucleus showing that a well deformed prolate and quasispherical states coexist at low energy