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Nuclear and Energy Physics

Nuclear physics has as its objective the investigation and understanding of nuclei, which are the hearts of atoms and the place where almost all mass of visible matter resides. The rules of nuclear binding determine the number of stable isotopes and their relative abundance in the world we live. Nuclei are fermion systems comprising from a few to hundred of neutrons and protons. The systems are small enough to exhibit sharp quantum states, but also large enough to show collective degrees of freedom, like vibrations and rotations.


Combined X-Ray and Optical Images of the Crab Nebula. From the Hubble telescope, NASA


Nuclear physics is now pushing at new frontiers of isospin and temperature based on an increasing understanding of nuclear structure and reactions earned over the last decades. In spite of this progress, there are many questions not yet answered. The research group at the Oslo Cyclotron Laboratory (OCL) has provided break-through findings of the behavior of the nucleus in the transition region from quantum order to chaos. For example, our group was the first to experimentally verify the gradually melting of the nucleus as it heats up. Also, the study of the high-energy electromagnetic radiation has provided new information on the resonance modes of the nucleus.

The nuclear physics landscape, from nuclei to stars

The nuclear chart with magic proton and neutron numbers.


A major motivation for studying the atomic nucleus is to gain a fundamental understanding of our world, including its origin and future, as well as its current state. Nuclear physics can explain how stars continually work to release virtually all of the useful energy in the world, while at the same time assembling the various elements. Thus today there is a strong collaboration between the fields of nuclear physics and astrophysics.

There are many potential applications of nuclear physics, e.g. in energy production, medical diagnosis and treatments. There are still several challenges, which make nuclear physics a very interesting and active field of future research.


Experimental nuclear physicists use accelerators to study various aspects of the nucleus. The Oslo group uses their home facility OCL in several projects. However, we are also part of a large international network and perform many experiments abroad.

PHOENIX (Photon excitation and neutron emission cross (x) sections)

The PHOENIX Collaboration aims at delivering the total gamma-strength function of key isotopes. Photonuclear data from inverse Compton scattering experiments at the synchrotron facility of NewSUBARU in Japan will be combined with Oslo method data from OCL and other labs in order to obtain total gamma-strength functions. In addition, the collaboration includes novel theoretical calculations for the isotopes that are studied. The collaboration will deliver results to the IAEA-CRP F41032 project.

Member institutes of the collaboration (in addition to UiO):

Konan University, Japan

ELI-NP, Romania

Moscow State University, Russia


The beta-Oslo method

A new method to measure the gamma-strength functions and nuclear level densities for very neutron-rich isotopes has been developed in collaboration with nuclear-physics group at UiO and the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), USA. The beta-Oslo method will provide data constraints on neutron-capture reaction rates for processes where heavy elements are made in extreme astrophysical environments. 

A memorandum of understanding is signed between UiO and MSU, enabling easy student exchange for master and PhD students. MSU offers a wide range of (credit-giving) courses within nuclear physics and nuclear astrophysics.  

Member institutes of the collaboration (in addition to UiO):


University of Notre Dame, USA

UC Berkeley, Lawrence Berkeley National, Lawrence Livermore National Lab, USA


Some of our collaborators are: NSCL, MSU, USA, Isolde, CERN, Ganil, France, CEA, Saclay, France, LLNL, California, USA, LBNL, California, USA, iThemba LABS, South Africa, OUAL, Ohio University, Ohio, USA, IPNP, Charles University, Prague, Czech Republic, North Carolina State University, USA, and ATOMKI, Debrecen, Hungary.

Master and PhD program

The group offers various projects in the field of nuclear physics. The study may have different focuses (theoretical/experimental/instrumental) with respect to the interest and capabilities of the student. Some actual topics are:

  • Level density and gamma-ray strength functions
  • Nuclei far from the beta stability line and/or very heavy nuclei
  • Nuclear shape coexistence
  • Fission and nuclear energy
  • Application in nuclear medicine
  • Instrumentation and data acquisition

Please, do not hesitate to contact us (see group members in right column).

Tags: nuclear physics, nuclear structure, nuclear medicine, spectroscopy, energy physics, Oslo Cyclotron Laboratory, detectors, instrumentation, USA, Japan, South Africa
Published July 19, 2012 11:36 AM - Last modified Nov. 5, 2021 1:05 PM


Group leader Sunniva Siem

Visiting address:
Physics Building
Sem Sælands vei 24
0371 OSLO

Mail address:
Nuclear and Energy Physics Group
P.O. Box 1048 - Blindern
NO-0316 OSLO


Oslo Cyclotron Laboratory
Department of Physics