dortheg

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Read more about my projects here (Norwegian):

Uventet resultat ga innsikt i hva som skjer når atomkjerner splittes

Student-eksperiment på plutonium vekker oppsikt blant toppforskere

Academic interests

Fission: what happens when heavy nuclei split?

In 1938, Otto Hahn and Fritz Strassmann stumbled upon something odd. They had bombarded the heavy nucleus uranium with neutrons, maybe expecting to find neighbouring elements among the reaction products. Instead, they found barium; a nucleus about half the mass of the original uranium, and far out of reach for any known nuclear reaction.

Over 80 years have passed since these findings were published, and we now know that Otto Hahn and Fritz Strassmann had induced fission in uranium. In this violent process, the nucleus rips apart and forms two smaller fission fragments while enormous amounts of energy is emitted. (Approximately a million times as much as in any chemical reaction!)

With the possibility of this huge energy release, fission was quickly applied in both energy production and weapons. Therefore, it might be surprising to hear that after 80 years of research, we are still yet to find a complete description of the fission process. Fission is a many-body quantum mechanical problem and is exceptionally difficult to describe - and thus also incredible fascinating to study. 

I'm working with a small piece of the complicated fission puzzle, and I study the photons emitted in the fission process. We cannot see directly what happens in fission as the heavy nucleus splits, but the emitted photons carry information about the excitation energy and angular momentum of the system. By trying to understand the radiated fission photons, we hope to gain new insights into the mystery that is the fission process.

Together with colleagues from Norway and abroad, I take part in conducting experiments to measure these fission photons, at the same time as we test to see if the state-of-the-art fission models can reproduce the experimental results. I thus work in the border between experiment and theory, which I think is amazing - I both get insights into the best fission models at the same time as I can propose new experiments to further push the border of our knowledge.

Do you think this sounds exciting? Feel free to send me a mail or drop by my office!

Education 

B.Sc University of Oslo: Physics, Astronomy and Meteorology, 2014-2017

M.Sc University of Oslo: Nuclear Physics, 2017-2019

PhD Student University of Oslo: Nuclear Physics, 2019 - 2023

Teaching

FYS4580, Lecturer, fall 2019, 2021 and 2023

FYS3500, Colloquium teacher, spring 2020, 2021

 

 

 

Tags: nuclear physics, fission

Publications

  • Hiver, C.; Wilson, J. N.; Pasqualato, G.; Lebois, M.; Charles, G. & Lopez-Martens, A. [Show all 52 contributors for this article] (2025). HIGH-RESOLUTION STUDIES OF ISOMERIC STATES IN 236U WITH THE nu-Ball2 SPECTROMETER. Acta Physica Polonica B, Proceedings Supplement. ISSN 1899-2358. 18(2). doi: 10.5506/APhysPolBSupp.18.2-A25. Full text in Research Archive
  • Paulsen, Wanja; Li, Kevin Ching Wei; Siem, Sunniva; Ingeberg, Vetle Wegner; Larsen, Ann-Cecilie & Eriksen, Tomas Kvalheim [Show all 15 contributors for this article] (2025). Remeasuring the γ-decay branching ratio of the Hoyle state. Physical Review C. ISSN 2469-9985. 112. doi: 10.1103/2h2s-sbyx. Full text in Research Archive
  • Torvund, Gulla Louise Serville; Ernoult, Marc; Courtin, Fanny; Doligez, Xavier; Gjestvang, Dorthea & Siem, Sunniva [Show all 7 contributors for this article] (2025). Multi-MOX: Facilitating plutonium multi-recycling in the French PWR fleet. Annals of Nuclear Energy. ISSN 0306-4549. 223. doi: 10.1016/j.anucene.2025.111641. Full text in Research Archive
  • Thisse, D.; Lebois, M.; Verney, D.; Wilson, J.N.; Jovančević, N. & Rudigier, M. [Show all 78 contributors for this article] (2023). Study of N= 50 gap evolution around Z= 32 : new structure information for <sup>82</sup> Ge. European Physical Journal A. ISSN 1434-6001. 59(7). doi: 10.1140/epja/s10050-023-01051-2. Full text in Research Archive
  • Gjestvang, Dorthea; Wilson, J.N.; Al-Adili, A.; Siem, Sunniva; Gao, Z. & Randrup, J. [Show all 74 contributors for this article] (2023). Examination of how properties of a fissioning system impact isomeric yield ratios of the fragments. Physical Review C. ISSN 2469-9985. 108(6). doi: 10.1103/PhysRevC.108.064602. Full text in Research Archive
  • Pogliano, Francesco; Garrote, Frank Leonel Bello; Larsen, Ann-Cecilie; Berg, Hannah Christine; Gjestvang, Dorthea & Görgen, Andreas [Show all 19 contributors for this article] (2023). Observation of a candidate for the M1 scissors resonance in odd-odd Ho 166. Physical Review C. ISSN 2469-9985. 107(3). doi: 10.1103/PhysRevC.107.034605. Full text in Research Archive
  • Pogliano, Francesco; Larsen, Ann-Cecilie; Markova, Maria; Garrote, Frank Leonel Bello; Bjørøen, Marianne Møller & Eriksen, Tomas Kvalheim [Show all 17 contributors for this article] (2022). Indirect measurement of the (n,γ) Sb 127 cross section. Physical Review C. ISSN 2469-9985. 106(1). doi: 10.1103/PhysRevC.106.015804. Full text in Research Archive
  • Guttormsen, Magne Sveen; Ay, Kursad Osman; Ozgur, Mustafa; Algin, Emel; Larsen, Ann-Cecilie & Garrote, Frank Leonel Bello [Show all 26 contributors for this article] (2022). Evolution of the γ -ray strength function in neodymium isotopes. Physical Review C. ISSN 2469-9985. 106(3). doi: 10.1103/PhysRevC.106.034314. Full text in Research Archive
  • Markova, Maria; Larsen, Ann-Cecilie; Neumann-Cosel, Peter von; Bassauer, Sergej; Görgen, Andreas & Guttormsen, Magne Sveen [Show all 23 contributors for this article] (2022). Nuclear level densities and γ -ray strength functions in Sn 120,124 isotopes: Impact of Porter-Thomas fluctuations. Physical Review C. ISSN 2469-9985. 106(3). doi: 10.1103/PhysRevC.106.034322. Full text in Research Archive
  • Häfner, G.; Lozeva, R; Naïdja, H.; Lebois, M.; Jovančević, N. & Thisse, D. [Show all 72 contributors for this article] (2021). First lifetime investigations of iodine isotopes: The quest for collectivity. Physical Review C. ISSN 2469-9985. 104(1). doi: 10.1103/PhysRevC.104.014316. Full text in Research Archive
  • Markova, Maria; Neumann-Cosel, Neumann-Cosel von; Larsen, A.C.; Bassauer, S.; Görgen, A. & Guttormsen, Magne Sveen [Show all 25 contributors for this article] (2021). Comprehensive Test of the Brink-Axel Hypothesis in the Energy Region of the Pygmy Dipole Resonance. Physical Review Letters. ISSN 0031-9007. 127(18). doi: 10.1103/PhysRevLett.127.182501. Full text in Research Archive
  • Gjestvang, Dorthea; Siem, Sunniva; Zeiser, Fabio; Randrup, Jørgen; Vogt, Ramona & Garrote, Frank Leonel Bello [Show all 20 contributors for this article] (2021). The study of prompt fission γ rays at the Oslo Cyclotron Laboratory. The European Physical Journal Conferences. ISSN 2101-6275. doi: 10.1051/epjconf/202125600005. Full text in Research Archive
  • Gjestvang, Dorthea; Siem, Sunniva; Zeiser, Fabio; Randrup, Jørgen; Vogt, Ramona & Wilson, Jonathan Nicholas [Show all 19 contributors for this article] (2021). Excitation energy dependence of prompt fission γ-ray emission from 241Pu*. Physical Review C. ISSN 2469-9985. 103(3). doi: 10.1103/PhysRevC.103.034609. Full text in Research Archive
  • Häfner, G.; Naïdja, H.; Lebois, M.; Jovancevic, N.; Thisse, D. & Etasse, D [Show all 72 contributors for this article] (2021). Spectroscopy and lifetime measurements in 134,136,138Te isotopes and implications for the nuclear structure beyond N = 82. Physical Review C. ISSN 2469-9985. doi: 10.1103/PhysRevC.103.034317. Full text in Research Archive
  • Wilson, J. N.; Thisse, D; Lebois, Matthieu; Jovančević, Nikola; Gjestvang, Dorthea & Canavan, R [Show all 76 contributors for this article] (2021). Angular momentum generation in nuclear fission. Nature. ISSN 0028-0836. 590, p. 566–570. doi: 10.1038/s41586-021-03304-w. Full text in Research Archive
  • Gerst, RB; Blazhev, A.; Warr, N.; Wilson, J. N.; Lebois, M & Jovančević, Nikola [Show all 50 contributors for this article] (2020). Prompt and delayed γ spectroscopy of neutron-rich Kr 94 and observation of a new isomer. Physical Review C. ISSN 2469-9985. 102(6). doi: 10.1103/PhysRevC.102.064323. Full text in Research Archive
  • Adamska, E; Korgul, A; Fijałkowska, A; Miernik, K; Piersa, M & Canavan, R [Show all 73 contributors for this article] (2020). γ-ray Spectroscopy of 85Se Produced in 232Th Fission. Acta Physica Polonica B. ISSN 0587-4254. 51(3), p. 843–848. doi: 10.5506/APhysPolB.51.843. Full text in Research Archive
  • Jovančević, Nikola; Lebois, M; Wilson, JN; Thisse, D; Qi, L & Matea, I [Show all 73 contributors for this article] (2019). Spectroscopy of neutron induced reactions with the ν-ball spectrometer. Acta Physica Polonica B. ISSN 0587-4254. 50(3), p. 297–304. doi: 10.5506/APhysPolB.50.297. Full text in Research Archive

View all works in NVA

View all works in NVA

Published July 31, 2019 11:23 AM - Last modified Sep. 29, 2023 12:39 PM