P. Himpe

Magnetic moment of the fragmentation-aligned 61Fe (9/2(+)) isomer.

We report on the g factor measurement of an isomer in the neutron-rich (61)(26)Fe (E(*)=861 keV and T(1/2)=239(5) ns). The isomer was produced and spin aligned via a projectile-fragmentation reaction at intermediate energy, the time dependent perturbed angular distribution method being used for the measurement of the g factor. For the first time, due to significant improvements of the experimental technique, an appreciable residual alignment of the nuclear spin ensemble has been observed, allowing a precise determination of its g factor, including the sign: g=-0.229(2). In this way we open the possibility to study moments of very neutron-rich short-lived isomers, not accessible via other production and spin-orientation methods.

g factors of {sup 17}N and {sup 18}N remeasured

The g factors of the {sup 17}N and {sup 18}N ground states were remeasured using the {beta}-nuclear magnetic resonance ({beta}-NMR) technique on spin-polarized fragment beams at the LISE fragment separator at GANIL. Based on the g-factor results, the magnetic moments of {sup 17}N (I{sup {pi}}=1/2{sup -}) and {sup 18}N (I{sup {pi}}=1{sup -}) were deduced: |{mu}({sup 17}N)|=0.3551(4) {mu}{sub N} and |{mu}({sup 18}N)|=0.3273(4) {mu}{sub N}. Both results are in good agreement with and more precise than the earlier observed values.

Nuclear alignment in projectile fragmentation as a tool for moment measurements

The application of the Time Dependent Perturbed Angular Distribution (TDPAD) method to study isomeric states produced and oriented in projectile‐fragmentation reactions provides the opportunity to perform nuclear‐moment measurements in a wide range of neutron‐rich nuclei, unaccessible by other means. An absolute necessity for the application of the TDPAD technique is a spin‐aligned ensemble of nuclei. The preliminary results from a recent application of this method on 61mFe and 54mFe at GANIL, Caen, France showed that a significant increase of the amount of the observed alignment, compared to our previous measurement on 67mNi and 69mCu, can be obtained. Some experimental details, concerning the conservation of the reaction obtained alignment, are discussed.

Spectroscopy of the proton drip line nucleus 19Na by 1H(18Ne,p)18Ne elastic scattering

Abstract We have studied the resonant elastic scattering reaction 18 Ne+p in reverse kinematics, by using the intense (4 × 10 6 pps) 18 Ne radioactive beam at the Centre de Recherches du Cyclotron RIB facility at Louvain-la-Neuve. The recoil protons were detected at 20 different angles in the LEDA segmented silicon detector. The resulting elastic scattering cross sections have been analysed using the R-matrix method. We have observed for the first time the second excited state ( J π = 1/2+, l = 0) of the proton-rich nucleus 19 Na at the center-of-mass energy E c.m. = 1.066 ± 0.003 MeV with a proton width Γ p = 101 ± 3 keV. The Coulomb shift between the 1/2+ mirror levels in 190 and 19 Na is 0.73 MeV, among the largest values currently observed in light exotic nuclei.