We report on the second SOFIA experiment, dedicated to the fission yields of 236U*, analog to 235U(n,f). The measurement is based on the inverse kinematics method, using a relativistic, secondary ...beam of 236U. Both fission fragments are identified in mass and charge in the SOFIA recoil spectrometer. The obtained isotopic yields are compared with existing spectroscopy measurements and the elemental yields are used to discuss the treatment of the even-odd effect with energy in nuclear data libraries.
Fission is an extremely complex mechanism that requires a dynamical approach to describe the evolution of the process in terms of intrinsic and collective excitations of the nuclear constituents. In ...order to determine these effects a complex experimental setup was mounted at GSI, which allowed us for the first time the full identification in charge and mass of all fission fragments thanks to a magnetic separation and the use of the inverse kinematic technique. Moreover, we also measured the neutron multiplicities and the light-charged particles emitted in coincidence with fission. These complete kinematic measurements will be used to define sensitive observables to dissipative and transient effects in fission. In this manuscript we present the first results for the total fission cross sections.
A novel Si strip array to investigate reaction and decay mechanisms Stanoiu, M.; Sümmerer, K.; Mukha, I. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
10/2008, Letnik:
266, Številka:
19-20
Journal Article
Recenzirano
The performance of a novel set-up of double-sided silicon micro-strip detectors (DSSD) developed for the GSI-R3B project (reaction studies with relativistic radioactive beams) is presented. The ...set-up was used in an experiment aimed at measuring the two-proton decay of 19Mg. This experiment required to record simultaneously protons and the residual nuclei with good position and energy resolution. Our experimental results show that both protons and heavy ions ranging from Z=2 up to Z=12 can be identified with good signal-to-noise ratio and high energy and spatial resolution. This allowed to reconstruct 2- and 3-particle vertices with high precision, opening the possibility to measure lifetimes of very short-lived nuclei and to obtain precise angular correlations of the outgoing particles. This detection system serves as a prototype for the R3B recoil detector, which will be composed of a two-layer Si strip tracker.
The E1 strength distribution in Ni68 has been investigated using Coulomb excitation in inverse kinematics at the RB3-LAND setup and by measuring the invariant mass in the one- and two-neutron decay ...channels. The giant dipole resonance and a low-lying peak (pygmy dipole resonance) have been observed at 17.1(2) and 9.55(17) MeV, respectively. The measured dipole polarizability is compared to relativistic random phase approximation calculations yielding a neutron-skin thickness of 0.17(2) fm. A method and analysis applicable to neutron-rich nuclei has been developed, allowing for a precise determination of neutron skins in nuclei as a function of neutron excess.
One-neutron knockout reactions in a
9
Be target have been investigated at relativistic energies, near 700 MeV/
u
, for a set of
sd
-shell, neutron-rich nuclei. The experiment was performed in the FRS ...spectrometer, at GSI.
γ
-ray measurements were carried out by means of the MINIBALL
γ
-ray spectrometer and allowed the determination of partial cross-sections and branching ratios corresponding to the final states of the emerging knockout fragments. Experimental results are presented for
17
C,
19
N,
21
O and
25
F projectiles. The role of excited states of the
N
− 1 fragments in the composition of the ground state of these neutron-rich projectiles is outlined in this work.
One-neutron knockout reactions of 24–28Ne in a beryllium target have been studied in the Fragment Separator (FRS), at GSI. The results include inclusive one-neutron knockout cross-sections as well as ...longitudinal-momentum distributions of the knockout fragments. The ground-state structure of the neutron-rich neon isotopes was obtained from an analysis of the measured momentum distributions. The results indicate that the two heaviest isotopes, 27Ne and 28Ne, are dominated by a configuration in which a s1/2 neutron is coupled to an excited state of the 26Ne and 27Ne core, respectively.
One-neutron knockout reactions of Ne24-28 in a beryllium target have been studied in the Fragment Separator (FRS), at GSI. The results include inclusive one-neutron knockout cross-sections as well as ...longitudinal-momentum distributions of the knockout fragments. The ground-state structure of the neutron-rich neon isotopes was obtained from an analysis of the measured momentum distributions. The results indicate that the two heaviest isotopes, Ne-27 and Ne-28, are dominated by a configuration in which a s(1/2) neutron is coupled to an excited state of the Ne-26 and Ne-27 core, respectively. (C) 2010 Elsevier B.V. All rights reserved.
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