Étude de la structure des noyaux riches en neutrons autour de la fermeture de couches N=28 par spectroscopie gamma en ligne

CAEN-BU Sciences et STAPS (141182103) / SudocSTRASBOURG-Bib.Central Recherche (674822133) / SudocSudocFranceF

Magnetic dipole moments of 57,58,59Cu

In-gas-cell laser spectroscopy of the isotopes 57,58,59,63,65Cu has been performed at the LISOL facility using the 244.164-nm optical transition from the atomic ground state of copper. A detailed discussion on the hyperfine structure of 63Cu is presented. The magnetic dipole moments of the isotopes 57,58,59,65Cu are extracted based on that of 63Cu. The new value μ = +0.479(13)μN is proposed for 58Cu, consistent with that of a πp3/2 x νp3/2 ground-state configuration. Spin assignments for the radioactive isotopes 57,58,59Cu are confirmed. The isotope shifts between the different isotopes are also given and discussed.status: publishe

Magnetic Dipole Moment of 57;59Cu Measured by In-Gas-Cell Laser Spectroscopy

For the first time, in-gas-cell laser spectroscopy study of the 57,59,63,65Cu isotopes has been performed using the 244.164 nm optical transition from the atomic ground state of copper. The nuclear magnetic dipole moments for 57,59,65Cu relative to that of 63Cu have been extracted. The new value for 57Cu of mu(57Cu) = +2:582(7) mu_N is in strong disagreement with the previous literature value but in good agreement with recent theoretical and systematic predictions.status: publishe

Proton partial widths evaluation through the 30^{30}Si(3^3He,d)31^{31}P transfer reaction for understanding abundance anomalies in Globular Clusters

International audienceSome observed abundances in globular clusters have suggested the existence of multiple generations of stars within the clusters as the observations require temperature ranges higher than current stars. The 30Si(p,γ)31P reaction plays a key role in the synthesis of the observed abundances. The study of the 30Si(3He,d)31P transfer reaction is a tool for constraining the strengths of low-lying resonances, and the proton partial widths are the main ingredients for calculating those strengths. We present the method used for estimating the proton partial widths and their associated uncertainties

Charge radii of odd-A 191–211Po isotopes

Isotope shifts have been measured for the odd-A polonium isotopes 191–211Po and changes in the nuclear mean square charge radii δr2 have been deduced. The measurements were performed at CERN-ISOLDE using the in-source resonance-ionization spectroscopy technique. The combined analysis of these data and our recent results for even-A polonium isotopes indicates an onset of deformation already at 197,198Po, when going away from stability. This is significantly earlier than was suggested by previous theoretical and experimental studies of the polonium isotopes. Moreover and in contrast to the mercury isotopes, where a strong odd–even staggering of the charge radii of the ground states was observed by approaching the neutron mid-shell at N = 104, no such effect is present in polonium down to 191Po. Consequently the charge radii of both isomeric and ground states of the odd-A polonium isotopes follow the same trend as the even-A isotopes.status: publishe

Structure of 191Pb from α- and β-decay spectroscopy

Complementary studies of 191Pb have been made in the β decay of 191Bi at LISOL (CRC) and in the α decay of 195Po at ISOLDE (CERN). Fine structures in the α decay of the low-spin and high-spin isomers of 195Po have been fully resolved. Identification of the parent state is made possible via isomer selection based on narrow-band laser frequency scanning. The α-particle and γ -ray energies have been determined with greater precision. New α-particle and γ -ray energies are identified. Branching ratios in the decay of 195Po and 191Pb have been examined.status: publishe

Early onset of deformation in the neutron-decient polonium isotopes

In-source laser spectroscopy has been performed at CERN-ISOLDE with the RILIS laser ion source on 191-204, 206,208-211, 216, 218Po. New information on the B decay of 199Po were extracted in the process, challenging previous results. Large-scale atomic calculations were performed to extract the changes in the mean-square charge radius d(r2) from the isotope shifts. The d(r2) for the even-A isotopes reveal a large deviation from the spherical droplet model for N < 116.status: publishe

Precise Determination of the Unperturbed 8B Neutrino Spectrum

A measurement of the final state distribution of the 8B decay, obtained by implanting a 8B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyva¨skyla¨ [O. S. Kirsebom et al., Phys. Rev. C 83, 065802 (2011)]. It shows discrepancies with previously measured spectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, the neutrino spectrum is for the first time directly extracted from the measured final state distribution, thus avoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data, this leads to an improvement of the overall errors and the extension of the neutrino spectrum at high energy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of the solar neutrino flux as a function of energy.status: publishe

Investigation of a light Dark Boson existence: The New JEDI project

International audienceSeveral experiments around the world are looking for a new particle, named Dark Boson, which may do the link between the Ordinary Matter (which forms basically stars, planets, interstellar gas...) and the Hidden Sectors of the Universe. This particle, if it exists, would act as the messenger of a new fundamental interaction of nature. In this paper, the underlying Dark Sectors theory will be introduced first. A non-exhaustive summary of experimental studies carried out to date and foreseen in the incoming years will be presented after,including the 8Be anomaly. The last section will provide a status of the New JEDI**** project which aims to investigate the existence or not of a Dark Boson in the MeV range