| 1. |
- Aksyutina, Yuliya, 1983, et al.
(author)
-
Properties of the 7He ground state from 8He neutron knockout
- 2009
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 679:3, s. 191-196
-
Journal article (peer-reviewed)abstract
- The unbound nucleus 7He, produced in neutron-knockout reactions with a 240 MeV/u 8He beam in a liquid-hydrogen target, has been studied in an experiment at the ALADIN-LAND setup at GSI. From an R-matrix analysis the resonance parameters for 7He as well as the spectroscopic factor for the 6He(0+) + n configuration in its ground-state have been obtained. The spectroscopic factor is 0.61 confirming that 7He is not a pure single-particle state. An analysis of 5He data from neutron-knockout reactions of 6He in a carbon target reveals the presence of an s-wave component at low energies in the α+n relative energy spectrum. A possible low-lying exited state in 7He observed in neutron knockout data from 8He in a carbon target and tentatively interpreted as a Iπ=1/2− state, could not be observed in the present experiment. Possible explanations of the shape difference between the 7He resonance obtained in the two knockout reactions are discussed in terms of target-dependence or different reaction mechanisms at relativistic energies.
|
|
| 2. |
- Aksyutina, Y., et al.
(author)
-
Structure of the unbound nucleus Be-13: One-neutron knockout reaction data from Be-14 analyzed in a holistic approach
- 2013
-
In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 87:6
-
Journal article (peer-reviewed)abstract
- At the ALADIN-LAND setup at GSI the unbound nucleus Be-13 has been produced in one-neutron knockout reactions from a 304 MeV/nucleon relativistic beam of Be-14 ions impinging on a liquid hydrogen target. An analysis of the data including all available information about Be-13, and in particular recent data from a similar experiment performed at RIKEN, has been performed. A consistent description is reached. It is found that the excitation spectrum is dominated by s-waves at low energy, which solves problems from previous seemingly contradictory interpretations. A possible interference between two s-states in Be-13 is also discussed. The results indicate that the ground-state wave function of Be-14 is dominated by valence neutrons in the s-shell contributing with 60-75% of the total neutron knockout cross section.
|
|
| 3. |
- Caesar, C., et al.
(author)
-
Beyond the neutron drip line: The unbound oxygen isotopes O-25 and O-26
- 2013
-
In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 88:3
-
Journal article (peer-reviewed)abstract
- The very neutron-rich oxygen isotopes O-25 and O-26 are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F-26 and F-27 at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O-24 plus one or two neutrons, the O-25 ground-state energy and width are determined, and upper limits for the O-26 ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O-26 at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added.
|
|
| 4. |
- Chulkov, L. V., et al.
(author)
-
Large spin alignment of the unbound He-5 fragment after fragmentation of 240 MeV/nucleon He-6
- 1997
-
In: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 79:2, s. 201-204
-
Journal article (peer-reviewed)abstract
- Peripheral fragmentation of a 240 MeV/nucleon beam of the halo nucleus He-6 incident on carbon target has been studied in a kinematically complete experiment. It is found that one-neutron stripping to the unbound nucleus He-5 is the dominant fragmentation mechanism and that it leads to a spin alignment of He-5 in a plane perpendicular to the He-5 momentum vector. This is expected to be a common feature for all neutron halo nuclei.
|
|
| 5. |
- Cortina-Gil, D., et al.
(author)
-
One-neutron knockout of n-rich Ne isotopes at relativistic energies
- 2010
-
In: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 834:1-4, s. 485C-487C
-
Conference paper (peer-reviewed)abstract
- Longitudinal fragment-momentum distributions resulting front one-neutron knockout of 40 different neutron-rich exotic species (Z ranging from 6-13) have been recently measured at high-energy (700 A MeV) using the FRS at GSI. This paper concentrates on results obtained for the Ne isotopic chain where five isotopes (Ne-24-Ne-28) have been Studied. The comparison of those experimental results with simple model calculations shows the evolution of the nuclear structure across neutron numbers N=14,16 in this transitional region in the neighbourhood of the island of inversion.
|
|
| 6. |
- Humbert, F., et al.
(author)
-
Longitudinal and Transverse-Momentum Distributions of Li-9 Fragments from Break-up of Li-11
- 1995
-
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 347:3-4, s. 198-204
-
Journal article (peer-reviewed)abstract
- Transverse and longitudinal momentum distributions of Li-9 fragments from Li-11 break-up reactions in C, Al and Pb targets have been measured at 280 MeV/u. The two-neutron removal cross-section was measured to be sigma(-2n), = 0.26 +/- 0.02 b for the carbon target, sigma(-2n) = 0.47 +/- 0.08 b for the aluminum target and sigma(-2n), = 1.9 +/- 0.4 b for the lead target. No significant difference is observed between the narrow widths (FWHM approximate to 47 MeV/c) of the transverse and longitudinal momentum distributions of the Li-9 fragments. The physical implications of this are discussed.
|
|
| 7. |
- Maierbeck, P., et al.
(author)
-
Probing the single particle structure around Ca-54 with one-neutron knock-out
- 2008
-
In: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1012, s. 89-93
-
Conference paper (peer-reviewed)abstract
- The nuclei Ca-47 and Ti-55 were populated in one-neutron knock-out reactions at relativistic energies. Momentum distributions of the residual nuclei as well as gamma-ray spectra were measured at the GSI fragment separator (FRS). Preliminary results of the ongoing analysis including cross sections and spin/parity assignments are presented.
|
|
| 8. |
- Maierbeck, P., et al.
(author)
-
Structure of 55Ti from relativistic one-neutron knockout
- 2009
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 675:1, s. 22-27
-
Journal article (peer-reviewed)abstract
- Results are presented from a one-neutron knockout reaction at relativistic energies on 56Ti using the GSI FRS as a two-stage magnetic spectrometer and the Miniball array for gamma-ray detection. Inclusive and exclusive longitudinal momentum distributions and cross-sections were measured enabling the determination of the orbital angular momentum of the populated states. First-time observation of the 955(6) keV -hole state in 55Ti is reported. The measured data for the first time proves that the ground state of 55Ti is a 1/2- state, in agreement with shell-model calculations using the GXPF1A interaction that predict a sizable N=34 gap in 54Ca.
|
|
| 9. |
- Marganiec, C., et al.
(author)
-
Coulomb breakup of 17Ne from the viewpoint of nuclear astrophysics
- 2013
-
In: Proceedings of Science.
-
Conference paper (peer-reviewed)abstract
- By the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p,γ)17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section sCoul has been determined, which then will be converted into a photo-absorption cross section sphot o, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress.
|
|
| 10. |
- Marganiec, J., et al.
(author)
-
Experimental study of the O-15(2p, gamma) Ne-17 cross section by Coulomb Dissociation for the rp process
- 2016
-
In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
-
Conference paper (peer-reviewed)abstract
- The time-reversed reaction O-15(2p, gamma) Ne-17 has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of Ne-20 in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-(RB)-B-3 experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (sigma(Coul)) have been calculated, which provide a photoabsorption (sigma(photo)) and a radiative capture cross section (sigma(cap)). Additionally, important information about the nuclear structure of the Ne-17 nucleus will be obtained. The analysis is in progress.
|
|
