We have studied the structure of light neutron-rich nuclei around N = 16 by employing the in-beam gamma-ray spectroscopy technique using the fragmentation of secondary beams of Ne-25,Ne-26, ...Na-27,Na-28 and Mg-29,Mg-30 isotopes. This secondary-beam cocktail was obtained by the fragmentation of a 36 S beam at 77.5 MeV.A by the SISSI/GANIL facility. By a second-step fragmentation, we have measured gamma-ray-residue coincidences in C17-20 and O-23,O-24 and described the obtained levels in the framework of the shell model.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Results from a study in inverse kinematics of the $^{24}$Ne(d, pγ)$^{25}$Ne reaction, using a radioactive beam of $^{24}$Ne from the SPIRAL facility at GANIL, are reported. First, a brief overview is ...given of several methods using radioactive beams to study the classic single-nucleon transfer reactions such as (d, p) or (d, t)/(d, $^{3}$He), where the experimental design is strongly influenced by the extreme inverse kinematics. A promising approach to deliver good energy resolution is to combine a high geometrical efficiency for kinematically complete charged particle detection with a high efficiency array for gamma-ray detection. One of the first dedicated set-ups for this type of experiment is the TIARA silicon strip array combined with the EXOGAM segmented germanium array. Together they comprise a highly compact, position-sensitive particle array with 90% of 4π coverage, mounted inside a cubic arrangement of four segmented gamma-ray detectors in very close geometry with 67% of 4π active coverage. Using this setup, the structure of $^{25}$Ne has been studied via the (d, p) reaction. A pure ISOL beam of 10$^{5}$ s$^{-1}$ of $^{24}$Ne at 10 MeV/A was provided by SPIRAL and bombarded a CD$_{2}$ target of 1 mg/cm$^{2}$. The $^{25}$Ne was detected at the focal plane of the VAMOS spectrometer where the direct beam was separated and intercepted. Reaction protons were detected in coincidence with little background. Four resolved peaks were recorded between E$_{x}$ = 0 and 4 MeV. The data confirm and extend the results from a multinucleon transfer study using the ($^{13}$C,$^{14}$O) reaction. Further information has been obtained using the energies of coincident gamma-rays. The reactions $^{24}$Ne(d, dγ)$^{24}$Ne, $^{24}$Ne(d, t)$^{23}$Ne and $^{24}$Ne(d, $^{3}$He)$^{23}$F were recorded simultaneously and analysis of these is also underway.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Proton reaction cross-section measurements on various stable and neutron-rich nuclei (
4,6He,
7–9Li,
9–11Be,
21–24F,
22–26Ne,
25–29Na and
29–32Mg) were performed via the attenuation method at ...intermediate energies (∼35–
75
A
MeV) and using a cryogenic hydrogen target. The results are discussed in the framework of different approaches of the nucleon–nucleus potential.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Mass measurements of very neutron-rich nuclei near the N=20 and 28 shell closures are presented. Seven masses have been determined for the first time and the precision of 36 masses has been ...significantly improved. These results are used to investigate the evolution of the odd–even staggering of binding energies with neutron number. Special attention is paid to the evolution of the N=28 shell closure as the neutron dripline is approached. Changes in shell structure are observed around N=28 for the P and S isotopes but not for Si. This may be interpreted as a persistence of the shell closure at N=28 or as the result of a very sudden onset in deformation at 42Si.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar GiantDipole Resonance (ISGDR) compression modes have been studied in thedoubly-magic unstable nucleus $^{56}$Ni. They were measured by ...inelastic α-particlescattering in inverse kinematics at 50 MeV/u with the MAYA active targetat the GANIL facility. The centroid of the ISGMR has been obtained atEx = 19.1 ± 0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex = 17.4 ± 0.7 MeV. The strength distribution for the dipolemode shows similarity with the prediction from the Hartree-Fock (HF) basedrandom-phase approximation (RPA) 1. These measurements confirm inelasticα-particle scattering as a suitable probe for exciting the ISGMR and the ISGDRmodes in radioactive isotopes in inverse kinematics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Two fission experiments have been performed at GANIL using super(238)U beams at different energies and light targets. Different fissioning systems were produced with centre of mass energies from 10 ...to 240 MeV and their decay by fission was investigated with GANIL spectrometers. Fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of the fusion-fission mechanism.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A global optical model potential (GDP08) for {sup 3}He projectiles has been obtained by simultaneously fitting the elastic scattering data of {sup 3}He from targets of 40{<=}A{sub T}{<=}209 at ...incident energies of 30{<=}E{sub inc}{<=}217 MeV. Uncertainties and correlation coefficients between the global potential parameters were obtained by using the bootstrap statistical method. GDP08 was found to satisfactorily account for the elastic scattering of {sup 3}H as well, which makes it a global optical potential for the A=3 nuclei. Optical model calculations using the GDP08 global potential are compared with the experimental angular distributions of differential cross sections for {sup 3}He-nucleus and {sup 3}H-nucleus scattering from different targets of 6{<=}A{sub T}{<=}232 at incident energies of 4{<=}E{sub inc}{<=}450 MeV. The optical potential for the doubly-magic nucleus {sup 40}Ca, the low-energy correction to the real potential for nuclei with 58 < or approx. A{sub T} < or approx. 120 at E{sub inc}<30 MeV, the comparison with double-folding model calculations and the CH89 potential, and the spin-orbit potential parameters are discussed.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
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