| 1. |
- Albertsson, Martin, et al.
(författare)
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Calculated fission-fragment mass yields and average total kinetic energies of heavy and superheavy nuclei
- 2020
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 56:2
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Tidskriftsartikel (refereegranskat)abstract
- Fission-fragment mass and total-kinetic-energy (TKE) distributions following fission of even-even nuclides in the region 74 ≤ Z≤ 126 and 92 ≤ N≤ 230 , comprising 896 nuclides have been calculated using the Brownian shape-motion method. The emphasis is the region of superheavy nuclei. To show compatibility with earlier results the calculations are extended to include earlier studied regions. An island of asymmetric fission is obtained in the superheavy region, 106 ≤ Z≤ 114 and 162 ≤ N≤ 176 , where the heavy fragment is found to be close to 208Pb and the light fragment adjusts accordingly. Most experimentally observed α-decay chains of superheavy nuclei with Z> 113 terminate by spontaneous fission in our predicted region of asymmetric fission. In these cases, the pronounced large asymmetry is accompanied by a low TKE value compatible with measurements.
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| 2. |
- Albertsson, M., et al.
(författare)
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Formation of transfermium elements in reactions with 208Pb
- 2024
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Ingår i: Physical Review C. - 2469-9985. ; 110:1
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Tidskriftsartikel (refereegranskat)abstract
- Within the Langevin framework, we investigate the dynamics of the fusion process for production of transfermium elements in reactions of 48Ca, 50Ti, 54Cr, and 58Fe with 208Pb. After the reacting nuclei have made contact, the early dynamical stage is dominated by the dissipation of the initial radial kinetic energy, while the subsequent shape evolution is diffusive. The probability for surmounting the inner barrier and forming a compound system is obtained by simulating the evolution as a Metropolis random walk in a five-dimensional potential-energy landscape. Good agreement with the available data is obtained, especially for the maximal formation probability.
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| 3. |
- Almosly, W., et al.
(författare)
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Charged-current neutrino and antineutrino scattering off Cd-116 described by Skyrme forces
- 2014
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 89:2, s. 024308-
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Tidskriftsartikel (refereegranskat)abstract
- We perform calculations of the cross sections for charged-current neutrino and antineutrino scattering off Cd-116 using ten different Skyrme interactions, at energies typical of supernova neutrinos. We use the quasiparticle random-phase approximation in its charged-changing mode (pnQRPA) to construct the required nuclear wave functions for the participant initial and final states. We compare the results of these calculations with the results of calculations based on the Bonn one-boson-exchange potential. The response of Cd-116 to supernova neutrinos is calculated by folding the obtained cross sections with suitably parametrized Fermi-Dirac distributions of the electron-neutrino and electron-antineutrino energies.
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| 4. |
- Almosly, W., et al.
(författare)
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Theoretical estimates of supernova-neutrino cross sections for the stable even-even lead isotopes : Charged-current reactions
- 2016
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 94:4
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Tidskriftsartikel (refereegranskat)abstract
- A detailed study of the charged-current supernova electron neutrino and electron antineutrino scattering off the stable even-mass lead isotopes A=204, 206, and 208 is reported in this work. The proton-neutron quasiparticle random-phase approximation (pnQRPA) is adopted to construct the nuclear final and initial states. Three different Skyrme interactions are tested for their isospin and spin-isospin properties and then applied to produce (anti)neutrino-nucleus scattering cross sections for (anti)neutrino energies below 80 MeV. Realistic estimates of the nuclear responses to supernova (anti)neutrinos are computed by folding the computed cross sections with a two-parameter Fermi-Dirac distribution of the electron (anti)neutrino energies. The computed cross sections are compared with earlier calculations and the analyses are extended to take into account the effects coming from the neutrino oscillations.
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| 5. |
- Andersson, Lise-Lotte, et al.
(författare)
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Classification of Superdeformed Bands in the Mass A~60 Region
- 2008
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Ingår i: Nuclear Physics and Astrophysics. - : AIP. - 9780735406032 ; 1072, s. 211-214
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Konferensbidrag (refereegranskat)abstract
- The experimental knowledge of the Cu-61(29)32 and Zn-61(30)31 nuclei has been largely extended via the joint results from three experiments. The fusion-evaporation reaction used a Ar-36 beam and a Si-28 target foil to produce the two nuclei via the evaporation of either three protons (Cu-61) or two protons and a neutron (Zn-61). The experimental set-ups comprised the Ge-array GAMMASPHERE as well as neutron and charged-particle detectors placed around the target position. The resulting level schemes include around ten rotational superdeformed structures in each isotope. Most of them are linked to normally deformed states and in many cases spins and parities of the low-lying states in each structure have been determined. The collective structures are compared with results from configuration dependent Cranked Nilsson-Strutinsky calculations. The different structures are in general well understood from the calculation but the results do also suggest modifications of the standard Nilsson parameters in the mass A similar to 60 region.
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| 6. |
- Andersson, Lise-Lotte, et al.
(författare)
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Extensive Gamma-ray Spectroscopy of Normally and Superdeformed Structures in 61Cu
- 2008
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 36:3, s. 251-278
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Tidskriftsartikel (refereegranskat)abstract
- A largely extended experimental knowledge of the Cu-61(29)32 nucleus has been obtained from three experiments. Excited states in Cu-61 were produced via the fusion-evaporation reaction Si-28(Ar-36, 3p)Cu-61. In addition to the Ge array GAMMASPHERE, neutron and charged-particle detectors placed around the target position were used for high-performance particle spectroscopy. The constructed level scheme includes more than 160 energy levels and 320 gamma-ray transitions belonging to both normally deformed as well as superdeformed rotational structures. The multipolarities have been determined for the gamma-ray transitions and as a result spin-parity assignments are given for nearly all energy levels. Experimental results in the normally deformed region are compared with predictions from large-scale shell model calculations. The collective structures are compared with results from cranked Nilsson-Strutinsky calculations. The results reveal the need to modify the standard Nilsson parameters in the mass A similar to 60 region.
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| 7. |
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| 8. |
- Carlsson, Gillis, et al.
(författare)
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Calculating the nuclear mass in the very high angular momentum regime
- 2006
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 74:1
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Tidskriftsartikel (refereegranskat)abstract
- Macroscopic-microscopic methods are applied in the high-spin regime to calculate the nuclear binding energy ("mass") as a function of proton number, neutron number, and angular momentum. Masses at high spin are calculated using the cranked Nilsson-Strutinsky model together with two different liquid drop models, the Lublin-Strasbourg drop model and the finite range liquid drop model. When comparisons are made with experimental data, a similar agreement between theory and experiment is obtained as for ground-state masses.
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| 9. |
- Carlsson, Gillis, et al.
(författare)
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Calculations of nuclear masses at finite angular momenta
- 2006
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Ingår i: Physica Scripta. - 0031-8949. ; T125, s. 130-133
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Tidskriftsartikel (refereegranskat)abstract
- The macroscopic-microscopic method to calculate nuclear masses is extended into the high-spin regime in order to calculate the nuclear binding energy as a function of proton number, neutron number and angular momentum. We describe the method and exemplify it on recent experimental data.
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| 10. |
- Carlsson, Gillis, et al.
(författare)
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Collective vibrational states within the fast iterative quasiparticle random-phase approximation method
- 2012
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 86:1
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Tidskriftsartikel (refereegranskat)abstract
- An iterative method we previously proposed to compute nuclear strength functions [Toivanen et al., Phys. Rev. C 81, 034312 (2010)] is developed to allow it to accurately calculate properties of individual nuclear states. The approach is based on the quasiparticle random-phase approximation (QRPA) and uses an iterative non-Hermitian Arnoldi diagonalization method where the QRPA matrix does not have to be explicitly calculated and stored. The method gives substantial advantages over conventional QRPA calculations with regards to the computational cost. The method is used to calculate excitation energies and decay rates of the lowest-lying 2(+) and 3(-) states in Pb, Sn, Ni, and Ca isotopes using three different Skyrme interactions and a separable Gaussian pairing force.
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