SwePub
Sök i SwePub databas

  Extended search

Träfflista för sökning "WFRF:(Faestermann T.) "

Search: WFRF:(Faestermann T.)

  • Result 1-25 of 30
Sort/group result
   
EnumerationReferenceCoverFind
1.
  • 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.
  •  
2.
  • Schwertel, S., et al. (author)
  • One-neutron knockout from Sc51-55
  • 2012
  • In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 48:Dec., s. 191-10
  • Journal article (peer-reviewed)abstract
    • Results are presented from a one-neutron knockout experiment at relativistic energies of approximate to 420 A MeV on Sc51-55 using the GSI Fragment Separator as a two-stage magnetic spectrometer and the Miniball array for gamma-ray detection. Inclusive longitudinal momentum distributions and cross-sections were measured enabling the determination of the contributions corresponding to knockout from the nu p(1/2), nu p(3/2), (L = 1) and nu f(7/2), nu f(5/2) (L = 3) neutron orbitals. The observed L = 1 and L = 3 contributions are compared with theoretical cross-sections using eikonal knockout theory and spectroscopic factors from shell model calculations using the GXPF1A interaction. The measured inclusive knockout cross-sections generally follow the trends expected theoretically and given by the spectroscopic strength predicted from the shell model calculations. However, the deduced L = 1 cross-sections are generally 30-40% higher while the L = 3 contributions are about a factor of two smaller than predicted. This points to a promotion of neutrons from the nu f(7/2) to the nu p(3/2) orbital indicating a weakening of the N = 28 shell gap in these nuclei. While this is not predicted for the phenomenological GXPF1A interaction such a weakening is predicted by recent calculations using realistic low-momentum interactions V-lowk obtained by evolving a chiral N3LO nucleon-nucleon potential.
  •  
3.
  • Wadsworth, R., et al. (author)
  • THE NORTHWEST FRONTIER : SPECTROSCOPY OF N similar to Z NUCLEI BELOW MASS 100
  • 2009
  • In: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 40:3, s. 611-620
  • Journal article (peer-reviewed)abstract
    • The spectroscopy and structure of excited states of N similar to Z nuclei in the mass 70-100 region has been investigated using two techniques. In the A similar to 70-80 region fusion evaporation reactions coupled with the recoil-beta-tagging method have been employed at Jyvaskyla to study low-lying states in odd-odd N = Z nuclei. Results from these and other data for known odd-odd nuclei above mass 60 will be discussed. In the heavier mass 90 region a fragmentation experiment has been performed using the RIS-ING/FRS setup at GSI. This experiment was primarily aimed at searching for spin gap isomers in nuclei around A similar to 96. The objectives of the latter experiment will be discussed.
  •  
4.
  • Kröll, Th, et al. (author)
  • Quadrupole Collectivity of neutron-rich nuclei around 132Sn
  • 2008
  • In: Frontiers in Nuclear Structure, Astrophysics, and Reactions, FINUSTAR 2007. - : AIP. - 9780735405325 ; 1012, s. 296-299
  • Conference paper (peer-reviewed)abstract
    • We report on the "safe" Coulomb excitation of neutron-rich Cd, Xe, and Ba isotopes in the vicinity of the doubly-magic nucleus 132Sn. The radioactive nuclei have been produced by ISOLDE at CERN and postaccelerated by the REX-ISOLDE facility. The γ-decay of excited states has been detected by the MINIBALL array. The presented preliminary results for the B(E2) values are consistent with expectations from phenomenological systematics and will be compared with theoretical calculations.
  •  
5.
  • 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.
  •  
6.
  • Hinke, C. B., et al. (author)
  • Superallowed Gamow-Teller decay of the doubly magic nucleus 100Sn
  • 2012
  • In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 486:7403, s. 341-345
  • Journal article (peer-reviewed)abstract
    • The shell structure of atomic nuclei is associated with 'magic numbers' and originates in the nearly independent motion of neutrons and protons in a mean potential generated by all nucleons. During beta(+)-decay, a proton transforms into a neutron in a previously not fully occupied orbital, emitting a positron-neutrino pair with either parallel or antiparallel spins, in a Gamow-Teller or Fermi transition, respectively. The transition probability, or strength, of a Gamow-Teller transition depends sensitively on the underlying shell structure and is usually distributed among many states in the neighbouring nucleus. Here we report measurements of the half-life and decay energy for the decay of Sn-100, the heaviest doubly magic nucleus with equal numbers of protons and neutrons. In the beta-decay of Sn-100, a large fraction of the strength is observable because of the large decay energy. We determine the largest Gamow-Teller strength so far measured in allowed nuclear beta-decay, establishing the 'superallowed' nature of this Gamow-Teller transition. The large strength and the low-energy states in the daughter nucleus, In-100, are well reproduced by modern, large-scale shell model calculations.
  •  
7.
  • Mucher, D., et al. (author)
  • Shell Structure and Shape Changes in Neutron Rich Krypton Isotopes
  • 2009
  • In: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 1090, s. 587-588 672
  • Conference paper (peer-reviewed)abstract
    • B(E2;2(1)(+) -> 0(1)(+)) values have been measured for the unstable nuclei Kr-88 (N=52) and Kr-92 (N=56) using projectile Coulomb excitation at ISOLDE, CERN. With this experiment the local maximum in E(2(1)(+)) in Kr-92 and the role of the N=56 subshell closure can be studied.
  •  
8.
  • Park, Joochun, et al. (author)
  • Toward the limit of nuclear binding on the N = Z line : Spectroscopy of Cd-96
  • 2019
  • In: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 99:2
  • Journal article (peer-reviewed)abstract
    • A gamma -decaying isomeric state (tau(1/2) = 197(-17)(+19) ns) has been identified in Cd-96, which is one alpha particle away from the last known bound N = Z nucleus, Sn-100. Comparison of the results with shell-model calculations has allowed a tentative experimental level scheme to be deduced and the isomer to be interpreted as a medium-spin negative-parity spin trap based on the coupling of isoscalar (T = 0) and isovector (T = 1) neutron-proton pairs. The data also suggest evidence for the population of a 9(+) T = 1 state, which is predicted by shell-model calculations to be yrast. Such a low-lying T = 1 state, which is unknown in lighter mass even-even self-conjugate nuclei, can also be interpreted in terms of the coupling of T = 0 and T = 1 neutron-proton pairs.
  •  
9.
  • Blazhev, A, et al. (author)
  • High-energy excited states in 98 Cd
  • 2010
  • In: Journal of Physics: Conference Series. ; 205:1
  • Journal article (peer-reviewed)abstract
    • In 98 Cd a new high-energy isomeric γ -ray transition was identified, which confirms previous spin-parity assignments and enables for the first time the measurement of the E 2 and E 4 strength for the two decay branches of the isomer. Preliminary results on the 98 Cd high-excitation level scheme are presented. A comparison to shell-model calculations as well as implications for the nuclear structure around 100 Sn are discussed.
  •  
10.
  • Blazhev, A, et al. (author)
  • High-energy Excited States in 98Cd
  • 2010
  • In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596. ; 205
  • Journal article (peer-reviewed)abstract
    • In 98Cd a new high-energy isomeric γ-ray transition was identified, which confirms previous spin-parity assignments and enables for the first time the measurement of the E2 and E4 strength for the two decay branches of the isomer. Preliminary results on the 98Cd high-excitation level scheme are presented. A comparison to shell-model calculations as well as implications for the nuclear structure around 100Sn are discussed.
  •  
11.
  • Boutachkov, P., et al. (author)
  • High-spin isomers in 96Ag : excitations across the Z=38 and Z=50, N=50 closed shells
  • 2011
  • In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 84:4
  • Journal article (peer-reviewed)abstract
    • Excited states in (96)Ag were populated in fragmentation of an 850-MeV/u (124)Xe beam on a 4-g/cm(2) Be target. Three new high-spin isomers were identified and the structure of the populated states was investigated. The level scheme of (96)Ag was established, and a spin parity of (13(-)), (15(+)), and (19(+)) was assigned to the new isomeric states. Shell-model calculations were performed in various model spaces, including pi nu(p(1/2), g(9/2), f(5/2), p(3/2)) and the large-scale shell-model space pi nu(gds), to account for the observed parity changing M2 and E3 transitions from the (13(-)) isomer and the E2 and E4 transitions from the (19(+)) core-excited isomer, respectively. The calculated level schemes and reduced transition strengths are found to be in very good agreement with the experiment.
  •  
12.
  • Boutachkov, P., et al. (author)
  • Isomer and Beta-decay Spectroscopy of Tz=1 Isotopes Below the N=Z=50 Shell Gap
  • 2011
  • In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 312:9
  • Journal article (peer-reviewed)abstract
    • The RISING setup at the GSI-FRS facility was used to investigate the isomer and beta decays in N~Z~50 Cd, Ag and Pd isotopes. A preliminary analysis of the data has revealed new results on the Tz=1, 94Pd, 96Ag and 98Cd isotopes. In 94Pd a new high-spin isomer was observed, whilst in 96Ag 3 new isomeric states were identified, including core-excited states. In 98Cd a new high-energy isomeric γ-ray transition is observed, thus enabling us to confirm the previous spin assignment for the core-excited 12+ isomer.
  •  
13.
  •  
14.
  • Brock, T. S., et al. (author)
  • Observation of a new high-spin isomer in Pd-94
  • 2010
  • In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 82:6, s. 061309-
  • Journal article (peer-reviewed)abstract
    • A second gamma-decaying high-spin isomeric state, with a half-life of 197(22) ns, has been identified in the N = Z + 2 nuclide Pd-94 as part of a stopped-beam Rare Isotope Spectroscopic INvestigation at GSI (RISING) experiment. Weisskopf estimates were used to establish a tentative spin/parity of 19(-), corresponding to the maximum possible spin of a negative parity state in the restricted (p(1/2), g(9/2)) model space of empirical shell model calculations. The reproduction of the E3 decay properties of the isomer required an extension of the model space to include the f (5/2) and p(3/2) orbitals using the CD-Bonn potential. This is the first time that such an extension has been required for a high-spin isomer in the vicinity of Sn-100 and reveals the importance of such orbits for understanding the decay properties of high-spin isomers in this region. However, despite the need for the extended model space for the E3 decay, the dominant configuration for the 19(-) state remains (p p(1/2)(-1)g(9/2)(-3))(11)circle times(nu g(9/2)(-2))(8). The half-life of the known, 14(+), isomer was remeasured and yielded a value of 499(13) ns.
  •  
15.
  • Davies, P. J., et al. (author)
  • The role of core excitations in the structure and decay of the 16(+) spin-gap isomer in Cd-96
  • 2017
  • In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 767, s. 474-479
  • Journal article (peer-reviewed)abstract
    • The first evidence for beta-delayed proton emission from the 16(+) spin gap isomer in Cd-96 is presented. The data were obtained from the Rare Isotope Beam Factory, at the RIKEN Nishina Center, using the BigRIPS spectrometer and the EURICA decay station. beta p branching ratios for the ground state and 16(+) isomer have been extracted along with more precise lifetimes for these states and the lifetime for the ground state decay of Cd-95. Large scale shell model (LSSM) calculations have been performed and WKB estimates made for l = 0, 2, 4 proton emission from three resonance-like states in Ag-96, that are populated by the beta decay of the isomer, and the results compared to the new data. The calculations suggest that l = 2 proton emission from the resonance states, which reside similar to 5 MeV above the proton separation energy, dominates the proton decay. The results highlight the importance of core-excited wavefunction components for the 16(+) state.
  •  
16.
  • Grawe, H., et al. (author)
  • The (6+) isomer in 102Sn revisited : Neutron and proton effective charges close to the double shell closure
  • 2021
  • In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 820
  • Journal article (peer-reviewed)abstract
    • In a high-energy fragmentation experiment at GSI an Iπ = (6+) isomer and its γ-decay are identified in 102Sn, the two-neutron neighbour of the doubly-magic 100Sn. Its half-life is measured to be T1/2 = 367(11) ns. The possible existence of further isomers is discussed in the framework of large-scale shell model (LSSM) calculations including up to five particle-hole excitations of the 100Sn core. From the precise B(E2; 6+ → 4+) strength and the recently remeasured value for B(E2; 8+ → 6+) in the two-proton hole neighbour 98Cd effective E2 polarization charges for protons and neutrons were inferred including LSSM corrections within the full N=4 0hω space. The results are discussed in comparison to predicted and empirically determined effective operators.
  •  
17.
  • Haefner, G., et al. (author)
  • Properties of γ-decaying Isomers in the 100Sn Region Revisited
  • 2019
  • In: Acta Physica Polonica B. - : JAGIELLONIAN UNIV PRESS. - 0587-4254 .- 1509-5770. ; 50:3, s. 431-437
  • Journal article (peer-reviewed)abstract
    • The study of nuclei in the region around the N = Z doubly-magic nucleus 100Sn has been of long standing interest for the nuclear structure and nuclear astrophysics. Recently, Park et al.  have reported on properties of γ-decaying isomers and isomeric ratios in the vicinity of 100Sn. That experiment was performed at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center in Japan as a part of the EURICA campaign. Neutron-deficient nuclei were produced in a fragmentation reaction of a 124Xe primary beam on a 9Be target at an energy of 345 MeV/A. Secondary ions were separated and identified in the BigRIPS fragment separator and implanted in the silicon detector array WAS3ABi. The data presented here were obtained in another experiment performed at the RIBF using the same reaction but slightly different separator settings. New results of ratios of isomeric population and half-lives of γ-decaying isomers populated in the experiment are presented.
  •  
18.
  • Häfner, G., et al. (author)
  • Properties of γ-decaying isomers in the Sn 100 region populated in fragmentation of a Xe 124 beam
  • 2019
  • In: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 100:2
  • Journal article (peer-reviewed)abstract
    • A systematic study was performed of microsecond γ-decaying isomers around Sn100 produced in a fragmentation reaction of a Xe124 beam at 345 MeV/u at the Radioactive Ion Beam Factory of the RIKEN Nishina Center in Saitama, Japan. Half-lives of isomeric states in that region were remeasured allowing us to improve the currently available experimental information. Reduced transition probabilities were deduced and compared to shell-model calculations in various model spaces. The recently reported low-energy transitions in Rh92 and Ag96 were remeasured with improved precision. Additionally, experimental information on isomeric ratios, including five new ones, were extracted and compared to a previous experimental study and the sharp cutoff model of fragmentation reaction.
  •  
19.
  • Moschner, K., et al. (author)
  • Study of ground and excited state decays in N approximate to Z Ag nuclei
  • 2015
  • In: CGS15 - CAPTURE GAMMA-RAY SPECTROSCOPY AND RELATED TOPICS. - : EDP Sciences. - 9782759817948
  • Conference paper (peer-reviewed)abstract
    • A decay spectroscopy experiment was performed within the EURICA campaign at RIKEN in 2012. It aimed at the isomer and particle spectroscopy of excited states and ground states in the mass region below the doubly magic Sn-100. The N = Z nuclei In-98, Cd-96 and Ag-94 were of particular interest for the present study. Preliminary results on the neutron deficient nuclei Ag-93 and Ag-94 are presented. In Ag-94 a more precise value for the half-life of the ground state's superallowed Fermi transition was deduced. In addition the energy spectra of the mentioned decay could be reproduced through precise Geant4 simulations of the used active stopper SIMBA. This will enable us to extract Q(beta) values from the measured data. The decay of Ag-93 is discussed based on the observed implantation-decay correlation events.
  •  
20.
  • Nara Singh, B. S., et al. (author)
  • Exotic Nuclear Studies Around and Below A=100
  • 2011
  • In: 4th International Conference on Proton Emitting Nuclei and Related Topics, PROCON2011. - : AIP. - 9780735409835 ; 1409, s. 19-24
  • Conference paper (peer-reviewed)abstract
    • A RISING experiment with an aim to study exotic Cd nuclei was carried out at GSI-FRS facility. Some preliminary results from this experiment are presented here. In particular, the β decay of 96Cd to 96Ag revealed the existence of a high spin isomer predicted a few decades ago. In this context, the structures of both these nuclei are discussed. Shell model calculations using the Gross-Frenkel interaction are used to interpret the results.
  •  
21.
  • Rodriguez-Tajes, C., et al. (author)
  • Gamma-ray measurements in the one-neutron knockout of C-17, N-19, O-21 and F-25
  • 2012
  • In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 48:7, s. Article Number: 95-95
  • Journal article (peer-reviewed)abstract
    • 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. gamma-ray measurements were carried out by means of the MINIBALL gamma-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 C-17, N-19, O-21 and F-25 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.
  •  
22.
  • Rodriguez-Tajes, C., et al. (author)
  • One-neutron knockout from light neutron-rich nuclei at relativistic energies
  • 2010
  • In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 82:2
  • Journal article (peer-reviewed)abstract
    • One-neutron knockout reactions from neutron-rich nuclei, with Z=6-13 and N=8-22, were studied at the Fragment Separator (GSI) at high beam energies, around 700 MeV/nucleon. Structural phenomena such as the formation of one-neutron halos in odd-mass carbon isotopes (15,17,19C) will be discussed. In addition, one-neutron knockout measurements from 22N were carried out for the first time and demonstrate clearly the change from a 0d5/2 to a 1s1/2 orbital for the valence neutron, an effect that is expected above N=14 and that was also observed in 23O and 24F. The possibility of an anomalous structure of 26F, due to a significant 1s1/2 neutron admixture, will also be discussed in the light of the experimental data obtained in this work. Finally, the ground-state configuration of neutron-rich neon isotopes (24-28Ne) was studied, providing new information in a region that is relatively close to the island of inversion.
  •  
23.
  • Rodriguez-Tajes, C., et al. (author)
  • One-neutron knockout from Ne24-28 isotopes
  • 2010
  • In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 687:1, s. 26-30
  • Journal article (peer-reviewed)abstract
    • 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.
  •  
24.
  • Rodriguez-Tajes, C., et al. (author)
  • Structure of 22N and the N=14 subshell
  • 2011
  • In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 83:6
  • Journal article (peer-reviewed)abstract
    • One-neutron knockout data for N18-22 are analyzed in the eikonal approximation of the Glauber model. The role of the s-d shell and the crossing of the N = 14 neutron subshell are discussed. Of particular interest is the nucleus N-22, where the knockout data provide a sensitive experimental test for a possible halo structure of its ground state. The observation of a narrow momentum distribution of the N-21 fragments, together with an essential 1s(1/2) contribution needed to describe the observed longitudinal-momentum distribution, allow the firm conclusion that the ground state of N-22 is a well-developed nuclear halo. The results also show that the N = 14 subshell in N-22 is somewhat reduced as compared to that of O-23.
  •  
25.
  • Singh, B. S. Nara, et al. (author)
  • 16(+) Spin-Gap Isomer in (96)Cd
  • 2011
  • In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 107:17, s. 172502-
  • Journal article (peer-reviewed)abstract
    • A beta-decaying high-spin isomer in (96)Cd, with a half-life T(1/2) = 0.29(-0.10)(+0.11) s, has been established in a stopped beam rare isotope spectroscopic investigations at GSI (RISING) experiment. The nuclei were produced using the fragmentation of a primary beam of (124)Xe on a (9)Be target. From the half-life and the observed gamma decays in the daughter nucleus, (96)Ag, we conclude that the beta-decaying state is the long predicted 16(+) "spin-gap'' isomer. Shell-model calculations, using the Gross-Frenkel interaction and the pi nu(p(1/2,)g(9/2)) model space, show that the isoscalar component of the neutron-proton interaction is essential to explain the origin of the isomer. Core excitations across the N = Z = 50 gaps and the Gamow-Teller strength, Bd(GT) distributions have been studied via large-scale shell-model calculations using the pi nu(g, d, s) model space to compare with the experimental B(GT) value obtained from the half-life of the isomer.
  •  
Skapa referenser, mejla, bekava och länka
  • Result 1-25 of 30

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Close

Copy and save the link in order to return to this view