Ann-Cecilie Larsen

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Norwegian version of this page
Phone +47 22855486
Room V104
Available hours Anytime
Visiting address Physics building Sem Sælandsvei 24 0371 Oslo
Postal address Postboks 1048 Blindern 0316 Oslo

Academic Interests

What happens if the atomic nucleus is heated to several billion degrees?

How were the elements that we know of in the Universe made?

How can nuclear physics save lives?

The nuclear physics group at the Oslo Cyclotron Laboratory (OCL) has developed a method to measure the properties of atomic nuclei at very high temperatures. At these temperatures, the most important properties are the level density, which is how many quantum states available for the nucleus at a given excitation energy, and the gamma-ray strength function, which is a measure of the probability of electromagnetic decay for a certain gamma energy. These two quantities are indispensable for estimating astrophysical reaction rates, which in turn are used for modeling the creation of the various elements in, e.g., supernovae.

New results from the OCL experiments show that some nuclei have an enhanced probability for electromagnetic decay for low-energetic gamma rays. It turns out that these discoveries might have a huge impact on the astrophysical reaction rates of the so-called r-process (rapid neutron capture), which is believed to be the mechanism behind about 50% of the heavy elements we observe in the Universe. Dependent on the models applied in the calculations, the reaction rates can increase up to a factor of 300 for the most neutron-rich nuclei [A. C. Larsen and S. Goriely, Physical Review C 82014318 (2010)]. 

Atomic nuclei may also be used for efficient and precise cancer treatment. By shooting e.g. protons (ionized hydrogen gas) or carbon ions into a tumor, the cancer cells will die while the surrounding healthy tissue will receive a minimal dose compared to conventional radiation treatment. Proton and ion therapy is now a well established method of treatment in many countries, and hopefully this method will also be available for Norwegian cancer patients soon.


From spring 2021: FYS-MEK1110 - Mechanics

Lecturer, FYS4515 - Nuclear Physics I

Previous teaching


Higher education and employment history

Cand.mag. in Physics, Dec. 2002, Department of Physics, University of Oslo

Cand.scient. in Nuclear Physics, June 2004, Department of Physics, University of Oslo

Ph.D. in Nuclear Physics, May 2008, Department of Physics, University of Oslo

Research fellow, OCL nuclear physics group, June 2008 - Feb 2009, Department of Physics, University of Oslo

Post.doc., OCL nuclear physics group, Nov. 2009 - Feb 2011, Department of Physics, University of Oslo

Personal postdoc grant, Research Council of Norway, Nov 2011 - Oct 2014, Department of Physics, University of Oslo

Guest researcher, Université Libre de Bruxelles, spring 2013

Guest researcher, UC Berkeley/Lawrence Berkeley National Lab/Lawrence Livermore National Lab, fall 2013

Guest researcher, National Superconducting Cyclotron Laboratory/Michigan State University, summer 2014 

Fulbright fellow at the National Superconducting Cyclotron Laboratory/Michigan State University, fall 2016

Fulbright fellow at UC Berkeley/Lawrence Berkeley National Lab, spring 2017



Fulbright Scholarship, 2016-2017

Member of the Norwegian Academy for Science and Letters, 2017-

Prize for Young, Excellent Researchers, Research Council of Norway, fall 2016

Starting Grant (STG-ERC-2014), European Research Council, Grant Agreement No. 637686,  2015-2020

Personal postdoc grant from the Research Council of Norway, Project Grant No. 205528, 2011-2014

Best poster presentation award, Zakopane Conference on Nuclear Physics, 2006



Oslo Syklotronlaboratorium (OCL),

Université Libre de Bruxelles,

National Superconducting Cyclotron Laboratory, Michigan State University,

Lawrence Berkeley National Laboratory,

Institute of Nuclear Physics NCSR Demokritos,

Lawrence Livermore National Laboratory,


Tags: nuclear physics, nuclear astrophysics, detectors, Instrumentation


View all works in Cristin

  • Sørbø, Solveig & Larsen, Ann-Cecilie (2022). Ann-Cecilie Larsen om kjerneastrofysikk, løping og musikk. [Radio]. radiOrakel og podcast.
  • Larsen, Ann-Cecilie (2021). Solveigs speisa musikk Ann-Cecilie Larsen Om Kjerneastrofysikk, Løping Og Musikk. [Radio]. Podkast og radio.
  • Larsen, Ann-Cecilie (2021). Abels tårn - om gull og protoner. [Radio]. NRK P2 Ekko.
  • Larsen, Ann-Cecilie (2021). Abels tårn - om fusjon. [Radio]. NRK P2 Ekko.
  • Larsen, Ann-Cecilie (2021). The quest for the origin of heavy elements.
  • Larsen, Ann-Cecilie (2020). A bright-matter mystery: the quest for the origin of the elements.
  • Larsen, Ann-Cecilie (2020). Experimentally constrained neutron-capture rates for the intermediate and rapid neutron-capture processes.
  • Larsen, Ann-Cecilie (2019). Indirect, experimental constraints of (n,γ) reaction rates for the i- and r-process.
  • Larsen, Ann-Cecilie (2019). Constraining neutron-capture rates relevant to r-process and i-process nucleosynthesis.
  • Larsen, Ann-Cecilie (2019). Leading an ERC StG research team - some experiences and thoughts.
  • Larsen, Ann-Cecilie (2019). Mysteriet i hjertet av atomet - hvor lenge overlever nøytroner på avveie?
  • Larsen, Ann-Cecilie (2018). Constraining neutron-capture rates for r-process scenarios.
  • Larsen, Ann-Cecilie (2018). The beta-Oslo method: experimentally constrained (n,gamma) reaction rates relevant to the r-process.
  • Midtbø, Jørgen E.; Larsen, Ann-Cecilie & Renstrøm, Therese (2018). Extracting γ-strength functions from shell model calculations.
  • Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Midtbø, Jørgen E.; Crespo Campo, Lucia; Görgen, Andreas & Ingeberg, Vetle Wegner [Show all 11 contributors for this article] (2017). Gamma-widths, lifetimes and fluctuations in the nuclear quasi-continuum.
  • Larsen, Ann-Cecilie (2017). Alkymisten. [Newspaper]. Magasinet, Dagbladet.
  • Larsen, Ann-Cecilie (2017). Stjernestøv, supernovaer og atomkjerner – hvordan ble grunnstoffene til?
  • Larsen, Ann-Cecilie (2016). Programdeltagelse, Abels tårn. [Radio]. Radio, nettradio (NRK P2).
  • Tveten, Gry Merete; Spyrou, Artemis; Schwengner, Ronald; Naqvi, Farheen; Larsen, Ann-Cecilie & Eriksen, Tomas Kvalheim [Show all 23 contributors for this article] (2016). The Statistical Properties Of 92Mo And Implications For The p-process.
  • Larsen, Ann-Cecilie (2016). Novel techniques for constraining neutron-capture rates relevant to heavy-element nucleosynthesis.
  • Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Görgen, Andreas; Renstrøm, Therese; Siem, Sunniva & Tornyi, Tamas Gabor [Show all 7 contributors for this article] (2016). Is the generalized Brink-Axel hypothesis valid?
  • Larsen, Ann-Cecilie (2016). Paneldeltager Abels tårn, Ekko P2. [Radio]. Realfagsbiblioteket, UiO.
  • Larsen, Ann-Cecilie (2016). Experimental level densities and gamma strength functions for nuclear astrophysics.
  • Larsen, Ann-Cecilie (2015). Workshop on the (beta-)Oslo method, NSCL/MSU.
  • Larsen, Ann-Cecilie (2015). Applying for an ERC Starting Grant - some experiences and thoughts.

View all works in Cristin

Published Nov. 4, 2010 12:22 PM - Last modified Sep. 24, 2020 10:36 AM