0000000001110125
AUTHOR
R. Wolski
Transfer cross sections at near-barrier energy for the 24Mg + 90,92Zr systems
We have tested the hypothesis that for systems 24Mg + 90,92Zr, the shape of the barrier height distribution is not influenced by transfers processes. The experiment was performed using the ICARE detector system at the Warsaw Cyclotron. Having measured the transfer cross sections of the near-barrier collisions of 24Mg + 90,92Zr, we have found them to be roughly half of the value obtained for the 20Ne + 90,92Zr systems. From that observation, we conclude that in the 24Mg + 90,92Zr case, the leading cause of washing out the barrier distribution structure is the partial dissipation of relative kinetic energy into the non-collective excitation of the system. peerReviewed
T=5/2 states in 9Li: Isobaric analog states of 9He
The thick target inverse kinematic method was applied to the study of isobaric analog states in the neutron-rich nucleus 9Li. For this purpose, an excitation function for 8He+p elastic scattering was measured in the center-of-momentum energy range from 1.6 to 5.8 MeV. Three T=5/2 states in 9Li (isobaric analogs of 9He) were observed. Restrictions on the spin-parity assignments are provided according to R-matrix calculations, and conclusions regarding the structure of 9He are given. peerReviewed
Crossing the dripline to11Nusing elastic resonance scattering
The level structure of the unbound nucleus N-11 has been studied by C-10+p elastic resonance scattering in inverse geometry with the LISE3 spectrometer at GANIL, using a C-10 beam with an energy of 9.0 MeV/ nucleon. An additional measurement was done at the A1200 spectrometer at MSU. The excitation function above the C-10+p threshold has been determined up to 5 MeV. A potential-model analysis revealed three resonance states at energies 1.27(-0.05)(+0.18) MeV (Gamma = 1.44 +/- 0.2 MeV), 2.01(-0.05)(+0.15) MeV (Gamma = 0.84 +/- 0.2 MeV), and 3.75 +/- 0.05 MeV (Gamma = 0.60 +/- 0.05 MeV) with the spin-parity assignments I-pi=1/2+,1/2,-,5/2+, respectively. Hence, N-11 is shown to have a ground …
Resonance State inH7
The existence of the $^{7}\mathrm{H}$ nuclear system was investigated via a one-proton transfer reaction with a $^{8}\mathrm{He}$ beam at $15.4\mathrm{A}\text{ }\text{ }\mathrm{MeV}$ and a $^{12}\mathrm{C}$ gas target. The experimental setup was based on the active-target MAYA which allowed a complete reconstruction of the reaction kinematics. The existence of the $^{7}\mathrm{H}$ was confirmed with the identification of seven events where the system was formed with a resonance energy of ${0.57}_{\ensuremath{-}0.21}^{+0.42}\text{ }\text{ }\mathrm{MeV}$ above the $^{3}\mathrm{H}+4n$ threshold and a resonance width of ${0.09}_{\ensuremath{-}0.06}^{+0.94}\text{ }\text{ }\mathrm{MeV}$. This stu…
Structure of exotic 7He and 9He
The heavy helium isotopes 7,9 He were studied via their isobaric analog states (IAS) in 7,9 Li. The IAS were populated via resonance reactions of protons with radioactive beams of 6,8 He. The isospin-conserving neutron decay of T=3/2 resonances in 7 Li and proton decay of T=5/2 resonances in 9 Li were measured. New spectroscopic information on these states were obtained, and compared with the properties of levels in 7,9 He.
T=5/2states in9Li:Isobaric analog states of9He
The thick target inverse kinematic method was applied to the study of isobaric analog states in the neutron-rich nucleus ${}^{9}\mathrm{Li}.$ For this purpose, an excitation function for ${}^{8}\mathrm{He}+p$ elastic scattering was measured in the center-of-momentum energy range from 1.6 to 5.8 MeV. Three $T=5/2$ states in ${}^{9}\mathrm{Li}$ (isobaric analogs of ${}^{9}\mathrm{He})$ were observed. Restrictions on the spin-parity assignments are provided according to R-matrix calculations, and conclusions regarding the structure of ${}^{9}\mathrm{He}$ are given.
Crossing the Dripline to 11N Using Elastic Resonance Scattering
The level structure of the unbound nucleus 11N has been studied by 10C+p elastic resonance scattering in inverse geometry with the LISE3 spectrometer at GANIL, using a 10C beam with an energy of 9.0 MeV/u. An additional measurement was done at the A1200 spectrometer at MSU. The excitation function above the 10C+p threshold has been determined up to 5 MeV. A potential-model analysis revealed three resonance states at energies 1.27 (+0.18-0.05) MeV (Gamma=1.44 +-0.2 MeV), 2.01(+0.15-0.05) MeV, (Gamma=0.84 +-$0.2 MeV) and 3.75(+-0.05) MeV, (Gamma=0.60 +-0.05 MeV) with the spin-parity assignments I(pi) =1/2+, 1/2- and 5/2+, respectively. Hence, 11N is shown to have a ground state parity inversi…
Lifetime of 26S and a limit for its 2p decay energy
Unknown isotope 26S, expected to decay by two-proton (2p) emission, was studied theoretically and was searched experimentally. The structure of this nucleus was examined within the relativistic mean field (RMF) approach. A method for taking into account the many-body structure in the three-body decay calculations was developed. The results of the RMF calculations were used as an input for the three-cluster decay model worked out to study a possible 2p decay branch of this nucleus. The experimental search for 26S was performed in fragmentation reactions of a 50.3 A MeV 32S beam. No events of 26S or 25P (a presumably proton-unstable subsystem of 26S) were observed. Based on the obtained produ…
Production and Characterization of the $^{7}$H Resonance
Détecteur MAYA; International audience; The 7H resonance was produced via one-proton transfer reaction between a 8He beam at 15.4A MeV and a 12C gas target. The experimental setup was based on the active-target MAYA which allowed a complete reconstruction of the reaction kinematics. The characterization of the identified 7H events resulted in a resonance energy of 600 keV above the 3H+4n threshold and a resonance width of 100 keV. This study represents the first unambiguous proof of the existence of the 7H state.
Isobaric analog states as a tool for spectroscopy of exotic nuclei
Abstract Spectroscopy of neutron rich exotic isotopes via their isobaric analog states (IAS) in less exotic nuclei is discussed. Several different experimental techniques, which can be applied to search for IAS of exotic isotopes, are described. Successful application of these techniques to the studies of heavy helium isotopes 7 He and 9 He led to the observation of unknown IAS in 7 Li and 9 Li. Spectroscopic information for these states were obtained, and implication of these findings to the structure of 7,9 He is considered.
New perspectives in the studies of resonance scattering
We consider various possibilities for studies of nuclear structure in resonance reactions induced by radioactive beam. We discuss investigations on both sides of nuclear stability as well as studies of the a-cluster structure of light nuclei applying the reverse geometry thick target method.