| 1. |
- Becker, F, et al.
(författare)
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Status of the RISING Project at GSI
- 2005
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 25:Suppl 1, s. 719-722
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Tidskriftsartikel (refereegranskat)abstract
- The FRS-RISING set-up at GSI uses secondary radioactive beams at relativistic energies for nuclear structure studies. At GSI the fragmentation or fission of stable primary beams up to U-238 provide secondary beams with sufficient intensity to perform gamma-ray spectroscopy. The RISING set-up is described and results of the first RISING campaign are presented. New experimental methods at relativistic energies are being investigated. Future experiments focus on state-of-the art nuclear structure physics covering exotic nuclei all over the nuclear chart.
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| 2. |
- Jensen, DR, et al.
(författare)
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Coexisting wobbling and quasiparticle excitations in the triaxial potential well of Lu-163
- 2004
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 19:2, s. 173-185
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states of the nucleus Lu-163 have been populated through the fusion-evaporation reaction La-139(Si-29, 5n) with a beam energy of 157 MeV. In addition to the two lowest excited triaxial strongly deformed (TSD) bands, recently interpreted as one- and two-phonon wobbling excitations, a third excited TSD band has been firmly established decaying to the yrast TSD band. The assignment of this band as a three-quasiparticle band shows together with the normal deformed (ND) level scheme the presence not only of shape coexistence between ND and TSD structures, but also an interplay of wobbling and quasiparticle excitations in the triaxial strongly deformed potential well of Lu-163.
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| 3. |
- Kmiecik, M., et al.
(författare)
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Spin-alignment and g-factor Measurement of the I=12+ Isomer in 192Pb Produced in the Relativistic-energy Fragmentation of a 238U Beam
- 2010
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 45:2, s. 153-158
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Tidskriftsartikel (refereegranskat)abstract
- The feasibility of measuring g-factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623 keV I-pi = 12(+) isomer in Pb-192 with tau = 1.57 mu s has been produced using the fragmentation of a 1 A GeV U-238 beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)% of the maximum possible, is preserved during the separation process allowing the determination of magnetic moments. The measured values of the lifetime, tau = 1.54(9) mu s, and the g-factor, g = -0.175(20), agree with the results of previous investigations using fusion-evaporation reactions.
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| 4. |
- Korten, W., et al.
(författare)
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Physics opportunities with the Advanced Gamma Tracking Array : AGATA
- 2020
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 56:5
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Forskningsöversikt (refereegranskat)abstract
- New physics opportunities are opening up by the Advanced Gamma Tracking Array, AGATA, as it evolves to the full 4 pi instrument. AGATA is a high-resolution gamma -ray spectrometer, solely built from highly segmented high-purity Ge detectors, capable of measuring gamma rays from a few tens of keV to beyond 10 MeV, with unprecedented efficiency, excellent position resolution for individual gamma -ray interactions, and very high count-rate capability. As a travelling detector AGATA will be employed at all major current and near-future European research facilities delivering stable and radioactive ion beams.
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| 5. |
- Lagergren, K, et al.
(författare)
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Evidence for excited states in Ag-95
- 2002
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Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 14:4, s. 393-396
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Tidskriftsartikel (refereegranskat)abstract
- The first evidence for excited states in Ag-95 is presented. Ag-95 is the heaviest T-z = 1/2 nucleus for which gamma-rays have been identified. The reaction Ca-40(Ni-58, 1p2n)Ag-95 was used in the experiment, which resulted in the assignment of three gamma-rays to Ag-95. A detector system consisting of the detector arrays Euroball, Neutron Wall and Euclides was used to detect gamma-rays, neutrons and charged particles, respectively.
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| 6. |
- Pasqualato, G., et al.
(författare)
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Shape evolution in even-mass 98-104Zr isotopes via lifetime measurements using the γ γ-coincidence technique
- 2023
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Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 59:11
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Tidskriftsartikel (refereegranskat)abstract
- The Zirconium (Z = 40) isotopic chain has attracted interest for more than four decades. The abrupt lowering of the energy of the first 2(+) state and the increase in the transition strength B(E2; 2(1)(+) -> 0(1)(+) ) going from Zr-98 to Zr-100 has been the first example of "quantum phase transition" in nuclear shapes, which has few equivalents in the nuclear chart. Although a multitude of experiments have been performed to measure nuclear properties related to nuclear shapes and collectivity in the region, none of the measured lifetimes were obtained using the Recoil Distance Doppler Shift method in the gamma gamma-coincidence mode where a gate on the direct feeding transition of the state of interest allows a strict control of systematical errors. This work reports the results of lifetime measurements for the first yrast excited states in Zr98-104 carried out to extract reduced transition probabilities. The new lifetime values in gamma gamma-coincidence and gamma-single mode are compared with the results of former experiments. Recent predictions of the Interacting Boson Model with Configuration Mixing, the Symmetry Conserving Configuration Mixing model based on the Hartree-Fock- Bogoliubov approach and the Monte Carlo Shell Model are presented and compared with the experimental data.
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| 7. |
- Podolyak, Zs., et al.
(författare)
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Structure of Neutron-rich Nuclei Around the N=126 Closed Shell; the Yrast Structure of 205Au up to Spin-parity I = (19/2+)
- 2009
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 42:3, s. 489-493
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Konferensbidrag (refereegranskat)abstract
- Heavy neutron-rich nuclei have been populated through the relativistic fragmentation of a Pb-208(82) beam at E/A = 1 GeV on a 2.5 g/cm(2) thick Be target. The synthesised nuclei were selected and identified in-flight using the fragment separator at GSI. Approximately 300 ns after production, the selected nuclei were implanted in an similar to 8 mm thick perspex stopper, positioned at the centre of the RISING gamma-ray detector spectrometer array. A previously unreported isomer with a half-life T-1/2 = 163(5) ns has been observed in the N = 126 closed-shell nucleus Au-205(79). Through gamma-ray singles and gamma-gamma coincidence analysis a level scheme was established. The comparison with a shell model calculation tentatively identifies the spin-parity of the excited states, including the isomer itself, which is found to be I-pi = (19/2(+)).
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| 8. |
- Rudolph, Dirk, et al.
(författare)
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Evidence for an Isomeric 3/2- State in 53Co
- 2008
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 36:2, s. 131-138
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Tidskriftsartikel (refereegranskat)abstract
- The fragmentation of a 550MeV/u primary beam of Ni-58 on a Be-9 target has been used to measure time-and energy-correlated gamma decays following the implantation of event-by-event discriminated secondary fragments into a Be-9 stopper plate. A new isomeric gamma decay with T-1/2 = 14(6 4) ns and E-gamma = 646.2(2) keV is observed and attributed to the decay of the yrast 3/2-state in Co-53(27)26. This short-lived isomeric state has been populated by means of nuclear reactions during the stopping process of the secondary fragments. The experimental findings are discussed in the framework of large-scale spherical shell model calculations in conjunction with isospin symmetry-breaking residual interactions for the A = 53, Tz = +/- 1/2 mirror nuclei Co-53 and Fe-53.
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| 9. |
- Sohler, Dola, et al.
(författare)
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First identification of excited states in the T-z=1/2 nucleus Pd-93
- 2004
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 19:2, s. 169-172
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Tidskriftsartikel (refereegranskat)abstract
- The first experimental information about excited states in the N=Z+1 nucleus Pd-93 is presented. The experiment was performed using a 205 MeV Ni-58 beam from the Vivitron accelerator at IReS, Strasbourg, impinging on a bismuth-backed Ca-40 target. Gamma-rays, neutrons and charged particles emitted in the reactions were detected using the Ge detector array Euroball, the Neutron Wall liquid-scintillator array and the Euclides Si charged-particle detector system. The experimental level scheme is compared with the results of new shell model calculations which predict a coupling scheme with aligned neutron-proton pairs to greatly influence the level structure of Napproximate toZ nuclei at low excitation energies.
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| 10. |
- Sohler, D, et al.
(författare)
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Maximally aligned states in Ag-99
- 2003
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 16:2, s. 171-175
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Tidskriftsartikel (refereegranskat)abstract
- Excited states of Ag-99 were populated via the Cr-50 + Ni-58 (261 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron. detector systems for reaction channel separation. On the basis of the measured gammagamma-coincidence relations and angular distribution ratios a significantly extended level scheme has been constructed up to E-x similar to 7.8 MeV and I = 35/2. The experimental results were described within the framework of the shell model. Candidates for states fully aligned in the pig(9/2)(-3)nu(d(5/2),g(7/2))(2) valence configuration space were found at 4109 and 6265 keV.
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