| 1. |
- Maierbeck, P., et al.
(författare)
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Structure of 55Ti from relativistic one-neutron knockout
- 2009
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 675:1, s. 22-27
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Klimkiewicz, A., et al.
(författare)
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Pygmy Dipole Strength in Exotic Nuclei and the Equation of State
- 2009
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 181-184 461
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Konferensbidrag (refereegranskat)abstract
- A concentration of dipole strength at energies below the giant dipole resonance was observed in neutron-rich nuclei around Sn-132 in an experiment using the FRS-LAND setup. This so-called "pygmy" dipole strength can be related to the parameters of the symmetry energy and to the neutron skin thickness on the grounds of a relativistic quasiparticle random-phase approximation. Using this ansatz and the experimental findings for Sn-130 and 132 Sri, we derive a value of the symmetry energy pressure of (p) over bar (0) = 2.2 +/- 0.5 MeV/fm(3). Neutron skin thicknesses of R-n-R-p = 0.23 +/- 0.03 fm and 0.24 +/- 0.03 fm for Sn-130 and Sn-132, respectively, have been determined. Preliminary results on Ni-68 from a similar experiment using an improved setup indicate an enhanced cross section at low energies, while the results for Ni-58 are in accordance with results from photoabsorption measurements.
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| 3. |
- Maierbeck, P., et al.
(författare)
-
Probing the single particle structure around Ca-54 with one-neutron knock-out
- 2008
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1012, s. 89-93
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Konferensbidrag (refereegranskat)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.
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| 4. |
- Fehrenbacher, G., et al.
(författare)
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Measurement of the fluence response of the GSI neutron ball in high-energy neutron fields produced by 500 A Mev and 800 AMev deuterons
- 2007
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Ingår i: Radiation Protection Dosimetry. - 0144-8420 .- 1742-3406. ; 126:1-4, s. 497-500
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Tidskriftsartikel (refereegranskat)abstract
- Experiments were performed in Cave C of GSI (Gesellschaft fur Schwerionenforschung) using the LAND (Large Area Neutron Detector) in combination with the deflection magnet ALADIN (A LArge DIpol magNet) in front of the LAND where charged particles and neutrons can be separated. This arrangement is used to create high-energetic neutron fields by irradiation of a thick lead target (5 cm) with deuteron beams with the energies of 500 or 800 MeV per nucleon. In break-up reactions the neutron is separated from the proton which is deflected in the magnetic field of the ALADIN. The produced neutron radiation, which has a pronounced peak at the nucleon energy, is used to measure the fluence response of the GSI neutron ball. A thermoluminescence (TL) based spherical neutron dosemeter was developed for the area monitoring for the quantity H*(10) at high-energy accelerators. In the same experiment, the spectral neutron fluence Phi(E) is measured with the LAND in the energy range from 100 MeV to 1 GeV. The measured fluence responses are compared with results of FLUKA calculations and the corresponding fluence-to-dose conversion coefficients. The measured dosemeter responses are too high in comparison to the calculated ones (up to similar to 50%), the dosemeter reading gives dose values which are too high by a factor of 1.1-2.2 related to the corresponding fluence-to-dose conversion factors.
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| 5. |
- Mahata, K., et al.
(författare)
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Study of dipole excitations and the single particle structure of neutron rich Ni isotopes
- 2008
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1012, s. 389-391 453
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Konferensbidrag (refereegranskat)abstract
- An experiment was performed using the FRS-LAND setup at GSI to study the dipole strength distributions above neutron separation threshold for neutron-rich Ni isotopes. Measurements, using the same experimental setup, were also carried out to extract single particle occupancies via knockout reactions to investigate the structure and magicity of the neutron-rich Ni isotopes. The status of the data analysis and preliminary results are presented.
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