Browsing by Author "Kratz, K.L."

Now showing items 1-20 of 32

    • Applicability of the Hauser-Feshbach approach for the determination of astrophysical reaction rates 

      Rauscher, T.; Thielemann, Friedrich-Karl; Kratz, K.L. (1997-08-04)
      Nuclear Astrophysics requires the knowledge of reaction rates over a wide range of nuclei and temperatures. In recent calculations the nuclear level density – as an important ingredient to the statistical model (Hauser-Feshbach) ...

    • Astrophysical and nuclear physics aspects of the r-process 

      Thielemann, Friedrich-Karl; Freiburghaus, C.; Rauscher, T.; Kratz, K.L.; Pfeiffer, B.; Cowan, J.J. (World Scientific Publishing, 1998)
      The formation of elements as heavy as Th and U and beyond is due to the rapid neutron-capture process (r-process), which causes the production of highly unstable nuclei near the neutron drip-line and functions via neutron ...

    • The astrophysical r-process : A comparison of calculations following adiabatic expansion with classical calculations based on neutron densities and temperatures 

      Freiburghaus, C.; Rembges, J.F.; Rauscher, T.; Kolbe, E.; Thielemann, Friedrich-Karl; Kratz, K.L.; Pfeiffer, B.; Cowan, J.J. (1999-05-01)
      The rapid neutron-capture process (r-process) encounters unstable nuclei far from beta-stability. Therefore its observable features, like the abundances, witness (still uncertain) nuclear structure as well as the conditions ...

    • Astrophysics and nuclei far from stabilitys 

      Thielemann, F.K.; Kratz, K.L.; Pfeiffer, B.; Rauscher, T.; van Wormer, L.; Wiescher, M. (1994-03)
      We discuss unstable nuclei on the proton-rich and neutron rich side of stability and their properties of astrophysical relevance. The Coulomb barriers in charged-particle captures lead to a cycle pattern which is not ...

    • Beta-decay studies of neutron-rich Sc, Ti, V, Cr 

      Sorlin, O.; Dorfler, T.; Anne, R.; Bohmer, W.; Borrel, V.; Guillemaud Mueller, D.; Grevy, S.; Kratz, K.L.; Lewitowicz, M.; Mehren, T.; Mueller, A.C.; Ostrowsky, A.; Pougheon, F.; Rauscher, T.; Robinson, M.; SaintLaurent, M.G.; SchmidtOtt, W.D. (Editions Frontieres, 1995)

    • Calculations of fission rates for r-process nucleosynthesis 

      Panov, I.; Kolbe, E.; Pfeiffer, B.; Rauscher, T.; Kratz, K.L.; Thielemann, Friedrich-Karl (2005-01-24)
      Fission plays an important role in the r-process which is responsible; not only for the yields of transuranium isotopes, but may have a strong influence on the formation of the majority of heavy nuclei due to fission ...

    • Charged-particle and neutron-capture processes in the high-entropy wind of core-collapse supernovae 

      Farouqi, K.; Kratz, K.L.; Pfeiffer, B.; Rauscher, T.; Thielemann, Friedrich-Karl; Truran, J. W. (2010-04-01)
      The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic ...

    • Dependence of direct neutron capture on nuclear-structure models 

      Rauscher, T.; Bieber, R.; Oberhummer, H.; Kratz, K.L.; Dobaczewski, J.; Moller, P.; Sharma, M.M. (1998-04)
      The prediction of cross sections for nuclei far off stability is crucial in the field of nuclear astrophysics. We calculate direct neutron capture on the even-even isotopes Sn124-145 and Pb208-238 with energy levels, masses, ...

    • Direct neutron capture for magic-shell nuclei 

      Krausmann, E.; Balogh, W.; Oberhummer, H.; Rauscher, T.; Kratz, K.L.; Ziegert, W. (1996-01)
      In neutron capture for magic-shell nuclei the direct reaction mechanism can be important and may even dominate. As an example we investigated the reaction Ca-48(n, gamma)Ca-49 for projectile energies below 250 keV in a ...

    • Element synthesis in stars 

      Thielemann, Friedrich-Karl; Brachwitz, F.; Freiburghaus, C.; Kolbe, E.; Martinez-Pinedo, Gabriel; Rauscher, T.; Rembges, F.; Hix, W. R.; Liebendoerfer, M.; Mezzacappa, A.; Kratz, K.L.; Pfeiffer, B.; Langanke, K.; Nomoto, K.; Rosswog, S.; Schatz, H.; Wiescher, Michael (Elsevier, 2001)
      Except for H-1, H-2, He-3, He-4, and Li-7, originating from the Big Bang, all heavier elements are made in stellar evolution and stellar explosions. Nuclear physics, and in many cases nuclear structure far from stability, ...

    • The endpoint of the rp-process 

      Schatz, H.; Aprahamian, A.; Brown, B.A.; Gorres, J.; Herndl, H.; Kratz, K.L.; Moller, P.; Pfeiffer, B.; Rauscher, T.; Rembges, J.F.; Thielemann, F.K.; Wiescher, M.; vanWormer, L. (1997-08-04)

    • Explosive nucleosynthesis and the astrophysical r-process 

      Thielemann, Friedrich-Karl; Freiburghaus, C.; Rauscher, T.; Kolbe, E.; Pfeiffer, B.; Kratz, K.L.; Cowan, J.J. (American Institute of Physics (AIP), 1998)
      We give an overview of chemical equilibria in explosive burning and the role which neutron and/or proton separation energies play. We focus then on the rapid neutron-capture process (r-process) which encounters unstable ...

    • Explosive nucleosynthesis close to the drip lines 

      Thielemann, Friedrich-Karl; Freiburghaus, C.; Rauscher, T.; Rembges, F.; Rosswog, S.; Pfeiffer, B.; Kratz, K.L.; Schatz, H.; Wiescher, M. (1998-11)
      We give an overview of explosive burning and the role which neutron and/or proton separation energies play. We focus then on the rapid neutron capture process (r-process) which encounters unstable nuclei with neutron ...

    • First beta-decay studies of the neutron-rich isotopes Sc53-55 and V56-59 

      Sorlin, O.; Borrel, V.; Grevy, S.; Guillemaud-Mueller, D.; Mueller, A.C.; Pougheon, F.; Bohmer, W.; Kratz, K.L.; Mehren, T.; Moller, P.; Pfeiffer, B.; Rauscher, T.; Saint-Laurent, M.G.; Anne, R.; Lewitowicz, M.; Ostrowski, A.; Dorfler, T.; Schmidt-Ott, W.D. (1998-03-16)
      The neutron-rich isotopes Sc53-55 and V56-59 have been produced at GANIL in interactions of a 64.5 MeV/u Cu-65 beam with a Be-9 target. They were separated by the doubly achromatic spectrometer LISE3. Beta-decay half-lives ...

    • Fission barriers : How do they affect the R-process? 

      Panov, I.; Pfeiffer, B.; Kratz, K.L.; Kolbe, E.; Rauscher, T.; Thielemann, Friedrich-Karl (World Scientific Publishing, 2004-02)
      Fission is an important process which is responsible not only for the yields of transuranium isotopes, but may have a strong influence on the formation of the majority of heavy nuclei due to fission recycling in the ...

    • The Hamburg/ESO R-process Enhanced Star survey (HERES). I : Project description and discovery of two stars with strong enhancements of neutron-capture elements 

      Christlieb, N.; Beers, T.C.; Barklem, P.S.; Bessell, M.S.; Hill, V.; Holmberg, J.; Korn, A.J.; Marsteller, B.; Mashonkina, L.; Qian, Y.Z.; Rossi, S.; Wasserburg, G.J.; Zickgraf, F.J.; Kratz, K.L.; Nordstrom, B.; Pfeiffer, B.; Rhee, J.; Ryan, Sean G. (2004-12)

    • Heavy elements and age determinations 

      Thielemann, Friedrich-Karl; Hauser, P.; Kolbe, E.; Martinez-Pinedo, Gabriel; Panov, I.; Rauscher, T.; Kratz, K.L.; Pfeiffer, B.; Rosswog, S.; Liebendoerfer, M.; Mezzacappa, A. (2002-01)
      The age of the universe, measured from the Big Bang to the present, is at the focus of cosmology. Its determination relies, however, on the use of stellar objects or their products. Stellar explosions, like type Ia supernovae ...

    • Neutron captures and the r-process 

      Farouqi, K.; Kratz, K.L.; Pfeiffer, B.; Rauscher, T.; Thielemann, R.K. (American Institute of Physics (AIP), 2006)
      In order to study possible neutron-capture effects during an r-process, it is necessary to perform fully dynamical simulations. We have performed such calculations within the model of an adiabatically expanding high-entropy ...

    • Neutron-rich isotopes Ti-54-57 

      Dorfler, T.; Schmidt Ott, W.D.; Hild, T.; Mehren, T.; Bohmer, W.; Moller, P.; Pfeiffer, B.; Rauscher, T.; Kratz, K.L.; Sorlin, O.; Grevy, S.; Guillemaud Mueller, D.; Mueller, A.C.; Pougheon, F.; Anne, R.; Lewitowicz, M.; Ostrowsky, A.; Robinson, M.; Saint Laurent, M.G. (1996-12)
      The neutron-rich isotopes Ti-54-57 and Cr-58-60 are produced by fragmentation of a 64.5 MeV/nucleon Cu-65(26+) beam in a 90 mg/cm(2) Be-9 target. Following particle identification by energy loss and time of flight, the ...

    • Nuclear level density and the determination of thermonuclear rates for astrophysics 

      Rauscher, T.; Thielemann, Friedrich-Karl; Kratz, K.L. (1997-09)
      The prediction of cross sections for nuclei far off stability is crucial in the field of nuclear astrophysics. In recent calculations the nuclear level density-as an important ingredient to the statistical model ...