Speaker
Alexander Herlert
(European Organization for Nuclear Research (CERN))
Description
The nuclear mass is an important parameter in nuclear physics and astrophysics. The
experimental determination of precise and accurate values is a challenge, especially
for short-lived radionuclides far away from the valley of stability with low
production yields as well as half-lives down to the millisecond time scale. However,
these mass values are required for testing and modelling nucleosynthesis theories
that describe how elements and nuclides are formed in stellar evolution, e.g.,
violent processes like supernovae explosions.
For the calculations of the various pathways from hydrogen to the heavier elements
the nuclear properties of a large number of nuclides need to be known [1,2].
Especially in the case of the r-process, where elements heavier than iron are formed
by rapid neutron capture, nuclear structure data of neutron-rich nuclides far from
the valley of stability are required. The path of the r-process is determined by and
reflects nuclear structure. For example at the neutron shell N=50 it crosses through
the waiting point nuclide 80Zn. Slight deviations in the nuclear physics parameters
can lead to large discrepancies in the modeling of the subsequent nucleosynthesis
processes. One crucial parameter is the mass of the nuclides, which enters the
determination of neutron separation energies and the Q-values for the beta decays as
well as interaction cross-sections. They are thus essential for the study of the
r-process and other astrophysical aspects.
With the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN very precise and
accurate mass measurements with relative mass uncertainties down to dm/m=8x10-9 can
be achieved. Recently, the atomic masses of the neutron-rich zinc isotopes 71-81Zn
have been measured. For the first time the masses of 79Zn and 81Zn have been
determined. The new experimental data allow the investigation of nuclear structure at
the neutron shell N=50 for low Z. The possible impact on nuclear astrophysics and
further examples are discussed.
[1] M. Mukherjee et al., Phys. Rev. 93, 150801 (2004)
[2] D. Rodriguez et al., Phys. Rev. Lett. 93, 161104 (2004)
Author
Alexander Herlert
(European Organization for Nuclear Research (CERN))
Co-authors
Dr
Alban Kellerbauer
(CERN, Physics Department, 1211 Geneva 23, Switzerland)
Mr
Chabouh Yazidjian
(GSI, Planckstr. 1, 64291 Darmstadt, Germany)
Dr
Céline Guénaut
(CSNSM-IN2P3-CNRS, 91405 Orsay-Campus, France)
Dr
Dave Lunney
(CSNSM-IN2P3-CNRS, 91405 Orsay-Campus, France)
Dr
Frank Herfurth
(GSI, Planckstr. 1, 64291 Darmstadt, Germany)
Prof.
H.-Jürgen Kluge
(GSI, Planckstr. 1, 64291 Darmstadt, Germany)
Dr
Klaus Blaum
(Johannes Gutenberg-University, Institute of Physics, 55099 Mainz, Germany)
Prof.
Lutz Schweikhard
(Ernst-Moritz-Arndt-University, Institute of Physics, 17487 Greifswald, Germany)
Mr
Martin Breitenfeldt
(Ernst-Moritz-Arndt-University, Institute of Physics, 17487 Greifswald, Germany)
Mr
Michael Dworschak
(Johannes Gutenberg-University, Institute of Physics, 55099 Mainz, Germany)
Dr
Pierre Delahaye
(CERN, Physics Department, 1211 Geneva 23, Switzerland)
Mr
Sebastian George
(Johannes Gutenberg-University, Institute of Physics, 55099 Mainz, Germany)
Mr
Sudarshan Baruah
(Ernst-Moritz-Arndt-University, Institute of Physics, 17487 Greifswald, Germany)
Ms
Ulrike Hager
(University of Jyväskylä, Department of Physics, 40014 Jyväskylä, Finland)
