Oliver Wieland

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Research activity:

“Google scholar index” of O. Wieland

My main research activity is the field of nuclear structure physics. Experimental investigations, theoretical evaluations and technological developments.

My scientific interest is dedicated towards the measurement of Giant and Pymgy (Dipole) Resonances/Strength and experiments in exotic, neutron and proton rich nuclei under extreme conditions:

My experimental research is presently carried out at various laboratories such as LNL/LNS in Legnaro/Catania (Italy), GSI (Darmstadt-Germany), GANIL (Caen-France), RIBF-RIKEN (Tokyo-Japan), RCNP (Osaka-Japan), IFIN-HH (Măgurele-Romania) and Argonne National Lab. (Chicago-USA), using stable and radioactive beams and targets.

The Giant Dipole Resonance (GDR) can be described macroscopically as a collective excited state consisting in an oscillation of neutrons against protons in counter phase. Microscopically this self organized movement can be described as a coherent superposition of particle-hole excitations.
Experimentally the GDR has been studied both at zero temperature by photoabsorption measurements and at finite temperature in the decay of nuclei populated using heavy ion reactions.
The properties of the GDR are directly related to the temperature, spin of the rotating nucleus, neutron excess and isospin symmetry and are currently investigated in a campaign of experiments with both stable and radioactive beams.
With Exotic Nuclei I investigate the shell structure and collective excitations of nuclei far from the stability line. This has become a key topic of nuclear structure in recent years. Shells and sub-shells may differ significantly from those established from well-known nuclei near the valley of stability, especially as the number of neutrons is increased. Collective excitations are expected to fragment and shift their strength to lower energy Pygmy Dipole Resonances (PDR). The PDR has important implications in nuclear astrophysics. The r-process, the physics of neutron star mergers and neutron stars are strongly correlated to the PDR and neutron rich matter in general. It is a very difficult task to access experimentally such kind of neutron rich nuclei as the production cross sections decreases exponentially as we approach the neutron drip line. Only very recently, new Radioactive Beam Facilities have given the possibility to produce and excite such nuclei far from the stability line.
The RISING/PRESPEC project at GSI in Germany and Eurica/Sunflower project at RIKEN in Japan are intended to perform high resolution g-ray spectroscopy using the radioactive beam facility at GSI and RIKEN. Unstable beams at energies ranging from 100 up to 600 A·MeV are produced by fragmentation of relativistic heavy ion projectiles provided by the SIS synchrotron or RIBF. The fragment separator FRS or BigRIPS are used to select and focus the exotic fragments on a secondary target where arrays of HPGe, LaBr₃:Ce and BaF₂ detectors are located. Charged particle detectors and magnets enable an event-by-event tracking of the incoming radioactive projectiles and the reaction products, thus allowing for a selection of nuclei of interest and velocity reconstruction.

My research activity is reflected in various invited lectures and publications as can be seen in the following links:

§ invited lectures

§ publications

• supervision of thesis
• ”third mission”
• recent talk
• responsability
• lezioni (school)_1,2,3,4
• mix

NUCLEAR STRUCTURE EXPERIMENTAL GROUP old PAGE®

NUCLEAR STRUCTURE EXPERIMENTAL GROUP new PAGE®

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e-mail: wieland@mi.infn.it

Internet phone: