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Author Mengoni, D. et al; Gadea, A.; Algora, A.; Rubio, B.
Title Lifetime measurements of excited states in neutron-rich Ar-44,Ar-46 populated via a multinucleon transfer reaction Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 82 Issue 2 Pages 024308 - 7pp
Keywords
Abstract Lifetimes of low-lying excited states of the neutron-rich Ar-44,Ar-46 nuclei, populated via multinucleon transfer reactions, are measured by means of the differential recoil distance Doppler shift method. The extracted electromagnetic transition probabilities are compared with previous intermediate-energy Coulomb-excitation measurements and with large-scale shell-model calculations. The increase in the deduced B( E2; 2(+) -> 0(+)) transition probability from Ar-44 to the closed-shell nucleus Ar-46 contradicts the earlier results of Coulomb-excitation experiments. Shell-model calculations using different effective interactions agree with the new measured values.
Address [Mengoni, D.; Angus, L. J.; Orlandi, R.; Smith, J. F.; Wady, P. T.] Univ W Scotland, Sch Engn, Paisley PA1 2BE, Renfrew, Scotland, Email: mengoni@pd.infn.it
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000280759100002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 394
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Author n_TOF Collaboration (Fujii, K. et al); Domingo-Pardo, C.; Tain, J.L.
Title Neutron physics of the Re/Os clock. III. Resonance analyses and stellar (n, gamma) cross sections of Os-186,Os-187,Os-188 Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 82 Issue 1 Pages 015804 - 18pp
Keywords
Abstract Neutron resonance analyses have been performed for the capture cross sections of Os-186, Os-187, and Os-188 measured at the n_TOF facility at CERN. Resonance parameters have been extracted up to 5, 3, and 8 keV, respectively, using the SAMMY code for a full R-matrix fit of the capture yields. From these results average resonance parameters were derived by a statistical analysis to provide a comprehensive experimental basis for modeling of the stellar neutron capture rates of these isotopes in terms of the Hauser-Feshbach statistical model. Consistent calculations for the capture and inelastic reaction channels are crucial for the evaluation of stellar enhancement factors to correct the Maxwellian averaged cross sections obtained from experimental data for the effect of thermally populated excited states. These factors have been calculated for the full temperature range of current scenarios of s-process nucleosynthesis using the combined information of the experimental data in the region of resolved resonances and in the continuum. The consequences of this analysis for the s-process component of the Os-187 abundance and the related impact on the evaluation of the time duration of galactic nucleosynthesis via the Re/Os cosmochronometer are discussed.
Address [Fujii, K.; Abbondanno, U.; Belloni, F.; Milazzo, P. M.; Moreau, C.] Ist Nazl Fis Nucl, I-34149 Trieste, Italy, Email: Kaori.Fujii@ts.infn.it
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000279940200009 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 410
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Author n_TOF Collaboration (Mosconi, M. et al); Domingo-Pardo, C.; Tain, J.L.
Title Neutron physics of the Re/Os clock. I. Measurement of the (n, gamma) cross sections of Os-186,Os-187,Os-188 at the CERN n_TOF facility Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 82 Issue 1 Pages 015802 - 10pp
Keywords
Abstract The precise determination of the neutron capture cross sections of Os-186 and Os-187 is important to define the s-process abundance of Os-187 at the formation of the solar system. This quantity can be used to evaluate the radiogenic component of the abundance of Os-187 due to the decay of the unstable Re-187 (t(1/2) = 41.2 Gyr) and from this to infer the time duration of the nucleosynthesis in our galaxy (Re/Os cosmochronometer). The neutron capture cross sections of Os-186, Os-187, and Os-188 have been measured at the CERN n_TOF facility from 1 eV to 1 MeV, covering the entire energy range of astrophysical interest. The measurement has been performed by time-of-flight technique using isotopically enriched samples and two C6D6 scintillation detectors for recording the prompt. rays emitted in the capture events. Maxwellian averaged capture cross sections have been determined for thermal energies between kT = 5 and 100 keV corresponding to all possible s-process scenarios. The estimated uncertainties for the values at 30 keV are 4.1, 3.3, and 4.7% for Os-186, Os-187, and Os-188, respectively.
Address [Mosconi, M.; Domingo-Pardo, C.; Kaeppeler, F.; Audouin, L.; Bisterzo, S.; Dillmann, I.; Heil, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K.] KIT, Inst Kernphys, D-76021 Karlsruhe, Germany, Email: Marita.Mosconi@ptb.de
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000279940200007 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 409
Permanent link to this record
 

 
Author Ljungvall, J. et al; Gadea, A.
Title Onset of collectivity in neutron-rich Fe isotopes: Toward a new island of inversion? Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 81 Issue 6 Pages 061301 - 4pp
Keywords
Abstract The lifetimes of the first excited 2(+) states in Fe-62 and Fe-64 have been measured for the first time using the recoil-distance Doppler shift method after multinucleon transfer reactions in inverse kinematics. A sudden increase of collectivity from Fe-62 to Fe-64 is observed. The experimental results are compared with new large-scale shell-model calculations and Hartree-Fock-Bogolyubov-based configuration-mixing calculations using the Gogny D1S interaction. The results give a deeper understanding of the mechanism leading to an onset of collectivity near Ni-68, which is compared with the situation in the so-called island of inversion around Mg-32.
Address [Ljungvall, J.; Goergen, A.; Obertelli, A.; Korten, W.] CEA Saclay, IRFU, Serv Phys Nucl, F-91191 Gif Sur Yvette, France
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000278768900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 424
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Author n_TOF Collaboration (Tagliente, G. et al.); Domingo-Pardo, C.; Tain, J.L.
Title The Zr-92(n,gamma) reaction and its implications for stellar nucleosynthesis Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 81 Issue 5 Pages 055801 - 9pp
Keywords
Abstract Because the relatively small neutron capture cross sections of the zirconium isotopes are difficult to measure, the results of previous measurements are often not adequate for a number of problems in astrophysics and nuclear technology. Therefore, the Zr-92(n,gamma) cross section has been remeasured at the CERN n_TOF facility, providing a set of improved parameters for 44 resonances in the neutron energy range up to 40 keV. With this information the cross-section uncertainties in the keV region could be reduced to 5% as required for s-process nucleosynthesis studies and technological applications.
Address [Tagliente, G.; Colonna, N.; Marrone, S.; Terlizzi, R.] Ist Nazl Fis Nucl, I-70126 Bari, Italy, Email: giuseppe.tagliente@ba.infn.it
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000278144800074 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 444
Permanent link to this record