Ann-Cecilie Larsen

Associate Professor - Nuclear and Energy Physics

Norwegian version of this page

Email a.c.larsen@fys.uio.no

Phone +47 22855486

Mobile phone +47 95051841

Room V104

Available hours Anytime

Username

Visiting address Physics building Sem Sælandsvei 24 0371 Oslo

Postal address Postboks 1048 Blindern 0316 OSLO

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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 82, 014318 (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.

Teaching

From spring 2021: FYS-MEK1110 - Mechanics https://www.uio.no/studier/emner/matnat/fys/FYS-MEK1110/index-eng.html

Lecturer, FYS4515 - Nuclear Physics I https://www.uio.no/studier/emner/matnat/fys/FYS4515/index-eng.html

Previous teaching

colloquium teacher, FYS-MEK1110 - Mechanics http://www.uio.no/studier/emner/matnat/fys/FYS-MEK1110/index-eng.html
lab teacher, KJM-FYS5920 - Nuclear measurement techniques and instruments http://www.uio.no/studier/emner/matnat/kjemi/KJM-FYS5920/index-eng.html

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

Honoraria

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

Cooperation

Oslo Syklotronlaboratorium (OCL), http://ocl.uio.no

Université Libre de Bruxelles, http://www.ulb.ac.be/index.html

National Superconducting Cyclotron Laboratory, Michigan State University, http://www.nscl.msu.edu

Lawrence Berkeley National Laboratory, http://www.lbl.gov

Institute of Nuclear Physics NCSR Demokritos, http://www.inp.demokritos.gr/

Lawrence Livermore National Laboratory, https://www.llnl.gov/

CERN / ISOLDE

Tags: nuclear physics, nuclear astrophysics, detectors, Instrumentation

Gjestvang, Dorthea; Siem, Sunniva; Zeiser, Fabio; Randrup, Jørgen; Vogt, Ramona; Wilson, Jonathan Nicholas; Bello Garrote, Frank Leonel; Bernstein, Lee A.; Bleuel, DL; Guttormsen, Magne Sveen; Görgen, Andreas; Larsen, Ann-Cecilie; Malatji, Kgashane L.; Matthews, Eric Francis; Oberstedt, Andreas; Oberstedt, Stephan; Tornyi, Tamas Gabor; Tveten, Gry Merete & Voyles, Andrew (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 Show summary
Prompt fission γ rays (PFGs) resulting from the 240Pu(d,pf) reaction have been measured as a function of fissioning nucleus excitation energy Ex at the Oslo Cyclotron Laboratory. We study the average total PFG multiplicity per fission, the average total PFG energy released per fission, and the average PFG energy. No significant changes in these characteristics are observed over the range 5.75
Guttormsen, Magne Sveen; Alhassid, Yoram; Ryssens, Wouter; Ay, K.o.; Ozgur, Mustafa; Algin, Emel; Larsen, Ann-Cecilie; Bello Garrote, Frank Leonel; Crespo Campo, Lucia; Dahl-Jacobsen, Tomas; Görgen, Andreas; Hagen, Trine Wiborg; Ingeberg, Vetle Wegner; Kheswa, Bonginkosi Vincent; Klintefjord, Malin; Midtbø, Jørgen E.; Modamio, Victor; Renstrøm, Therese; Sahin, Eda; Siem, Sunniva; Tveten, Gry Merete & Zeiser, Fabio (2021). Strong enhancement of level densities in the crossover from spherical to deformed neodymium isotopes. Physics Letters B. ISSN 0370-2693. B816(136206) . doi: 10.1016/j.physletb.2021.136206
Malatji, Kgashane Leroy; Beckmann, Kristine Sønstevold; Wiedeking, Mathis; Siem, Sunniva; Goriely, Stephane; Larsen, Ann-Cecilie; Ay, Kursad Osman; Bello Garrote, Frank Leonel; Crespo Campo, Lucia; Görgen, Andreas; Guttormsen, Magne Sveen; Ingeberg, Vetle Wegner; Jones, Peter; Kheswa, Bonginkosi Vincent; von Neumann-Cosel, Peter; Ozgur, Mustafa; Potel, Gregory; Pellegri, Luna; Renstrøm, Therese; Tveten, Gry Merete & Zeiser, Fabio (2021). Statistical properties of the well deformed 153,155Sm nuclei and the scissors resonance. Physical Review C. ISSN 2469-9985. 103(1) . doi: 10.1103/PhysRevC.103.014309 Full text in Research Archive.
Midtbø, Jørgen Eriksson; Zeiser, Fabio; Lima, Erlend; Larsen, Ann-Cecilie; Tveten, Gry Merete; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel; Kvellestad, Anders & Renstrøm, Therese (2021). A new software implementation of the Oslo method with rigorous statistical uncertainty propagation. Computer Physics Communications. ISSN 0010-4655. 262 . doi: 10.1016/j.cpc.2020.107795 Full text in Research Archive.
Zeiser, Fabio; Tveten, Gry Merete; Bello Garrote, Frank Leonel; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Ingeberg, Vetle Wegner; Görgen, Andreas & Siem, Sunniva (2021). The gamma-ray energy response of the Oslo Scintillator Array OSCAR. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 985 . doi: 10.1016/j.nima.2020.164678 Full text in Research Archive.
Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Spyrou, Artemis & Liddick, Sean N. (2020). Experimentally constrained (n, γ) reaction rates relevant to r- and i-process nucleosynthesis. Acta Physica Polonica B. ISSN 0587-4254. 56(3), s 667- 676 . doi: 10.5506/APhysPolB.51.667
Ingeberg, Vetle Wegner; Siem, Sunniva; Wiedeking, Mathis; Sieja, Kamila; Bleuel, D.l.; Brits, C.P.; Bucher, T. D.; Dinoko, TS; Easton, JL; Görgen, Andreas; Guttormsen, Magne Sveen; Jones, P.; Kheswa, Bonginkosi Vincent; Khumalo, NA; Larsen, Ann-Cecilie; Lawrie, EA; Lawrie, JJ; Majola, SNT; Malatji, K. L.; Makhathini, L.; Maqabuka, B.; Negi, Dinesh; Noncolela, SP; Papka, P; Sahin, Eda; Schwengner, Ronald; Tveten, Gry Merete; Zeiser, Fabio & Zikhali, Bonginkosi Richard (2020). First application of the Oslo method in inverse kinematics. European Physical Journal A. ISSN 1434-6001. 56 . doi: 10.1140/epja/s10050-020-00070-7 Full text in Research Archive. Show summary
The γ-ray strength function (SF) and nuclear level density (NLD) have been extracted for the first time from inverse kinematic reactions with the Oslo method. This novel technique allows measurements of these properties across a wide range of previously inaccessible nuclei. Proton–γ coincidence events from the d(⁸⁷Kr,p)⁸⁶Kr reaction were measured at iThemba LABS and the γSF and NLD in ⁸⁶Kr was obtained. The low-energy region of the γSF is compared to shell-model calculations, which suggest this region to be dominated by M1 strength. The γSF and NLD are used as input parameters to Hauser–Feshbach calculations to constrain (n,γ) cross sections of nuclei using the TALYS reaction code. These results are compared to ⁸⁶Kr(n,γ) data from direct measurements.
Kibédi, T.; Alshahrani, B.; Stuchbery, A.E.; Larsen, Ann-Cecilie; Görgen, Andreas; Siem, Sunniva; Guttormsen, Magne Sveen; Giacoppo, Francesca; Morales, A.I.; Sahin, Eda; Tveten, Gry Merete; Bello Garrote, Frank Leonel; Crespo Campo, Lucia; Eriksen, Tomas Kvalheim; Klintefjord, Malin; Maharramova, Sabina; Nyhus, Hilde-Therese; Tornyi, Tamas Gabor; Renstrøm, Therese & Paulsen, Wanja (2020). Radiative Width of the Hoyle State from γ -Ray Spectroscopy. Physical Review Letters. ISSN 0031-9007. 125(18) . doi: 10.1103/PhysRevLett.125.182701 Full text in Research Archive.
Scholz, P.; Guttormsen, Magne Sveen; Heim, F.; Larsen, Ann-Cecilie; Mayer, J.; Savran, D.; Spieker, M.; Tveten, Gry Merete; Voinov, A.V.; Wilhelmy, J.; Zeiser, Fabio & Zilges, A. (2020). Primary γ-ray intensities and γ-strength functions from discrete two-step γ-ray cascades in radiative proton-capture experiments. Physical Review C. ISSN 2469-9985. . doi: 10.1103/PhysRevC.101.045806 Full text in Research Archive.
Brits, C.P.; Malatji, Kgashane L.; Wiedeking, M.; Kheswa, BV; Goriely, S.; Bello Garrote, Frank Leonel; Bleuel, D. L.; Giacoppo, Francesca; Görgen, Andreas; Guttormsen, Magne Sveen; Hadynska-Klek, Katarzyna; Hagen, Trine Wiborg; Hilaire, S.; Ingeberg, Vetle Wegner; Jia, H.; Klintefjord, Malin; Larsen, Ann-Cecilie; Majola, SNT; Papka, P.; Péru, S.; Qi, B.; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva; Tveten, Gry Merete & Zeiser, Fabio (2019). Nuclear level densities and γ-ray strength functions of 180,181,182Ta. Physical Review C. ISSN 2469-9985. 99(5) . doi: 10.1103/PhysRevC.99.054330 Full text in Research Archive.
Guttormsen, Magne Sveen; Goriely, Stephane; Larsen, Ann-Cecilie; Görgen, Andreas; Hagen, Trine Wiborg; Renstrøm, Therese; Siem, Sunniva; Syed, Naeem Ul Hasan; Tagliente, Giuseppe; Toft, Heidi Kristine; Utsunomiya, H.; Voinov, A.V. & Wikan, Kristine (2019). Indirect(n,γ)91,92Zr Cross SectionMeasurements for the s-Process, In Alba Formicola; Matthias Junker; Lucio Gialanella & Gianluca Imbriani (ed.), Nuclei in the Cosmos XV. Springer. ISBN 978-3-030-13875-2. 65. s 359 - 362
Krzysiek, Mateusz; Utsunomiya, Hiroaki; Gheorghe, Ioana; Filipescu, Dan Mihai; Renstrøm, Therese; Tveten, Gry Merete; Belyshev, Sergey; Stopani, Konstantin; Wang, Hongwei; Fan, Gongtao; Lui, Yiu-Wing; Symochko, Dmytro; Goriely, Stéphane; Larsen, Ann-Cecilie; Siem, Sunniva; Varlamov, Vladimir V.; Ishkhanov, Boris; Ari-Izumi, Takashi & Miyamoto, Shuji (2019). Photoneutron cross-section measurements for 165HO by the direct neutron-multiplicity sorting at Newsubaru. Acta Physica Polonica B. ISSN 0587-4254. 50(3), s 487- 494 . doi: 10.5506/APhysPolB.50.487
Kullmann, Ina Kristine Berentsen; Larsen, Ann-Cecilie; Renstrøm, Therese; Beckmann, Kristine Sønstevold; Bello Garrote, Frank Leonel; Crespo Campo, Lucia; Görgen, Andreas; Guttormsen, Magne Sveen; Midtbø, Jørgen E.; Sahin, Eda; Siem, Sunniva; Tveten, Gry Merete & Zeiser, Fabio (2019). First experimental constraint on the 191Os(n,γ) reaction rate relevant to s-process nucleosynthesis. Physical Review C. ISSN 2469-9985. 99(6) . doi: 10.1103/PhysRevC.99.065806 Full text in Research Archive. Show summary
The nuclear level density and γ -decay strength of 192 Os have been extracted using particle- γ coincidence data from the 192 Os ( α , α ′ γ ) 192 Os reaction by means of the Oslo method. The level density is found to be a rather smooth function of excitation energy, approximately following the constant temperature model. The γ -decay strength is compared to photoneutron cross-section data above the neutron separation energy, and to E 1 and M 1 strengths for nuclei in this mass region derived from primary transitions following neutron capture. Our results are in good agreement with these previous data and draw a consistent picture of the γ -strength function in the range E γ ≈ 1.5 – 6 MeV . Using the measured nuclear level density and γ -decay strength as input to the nuclear-reaction code talys, we provide the first experimentally constrained Maxwellian-averaged cross section (MACS) for the 191 Os ( n , γ ) 192 Os reaction relevant to s -process nucleosynthesis. The systematic uncertainties introduced by the normalization procedure of the level density and γ -strength function were investigated and propagated to the calculated Maxwellian-averaged cross section. The obtained result of the Maxwellian-averaged cross section at k B T = 30 keV , ⟨ σ ⟩ n , γ = 1134 ± 375 mb , is in very good agreement with the theoretical estimate provided by the KADoNiS project, giving experimental support to the adopted KADoNiS value. Good agreement is also found with MACS values obtained from other libraries, such as TENDL-2017, ENDF/B-VII.0, and JEFF.
Larsen, Ann-Cecilie; Liddick, Sean N.; Spyrou, Artemis; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel; Midtbø, Jørgen E. & Renstrøm, Therese (2019). The Beta-Oslo Method: ExperimentallyConstrained (n,γ) Reaction RatesRelevant to ther-Process, In Alba Formicola; Matthias Junker; Lucio Gialanella & Gianluca Imbriani (ed.), Nuclei in the Cosmos XV. Springer. ISBN 978-3-030-13875-2. 22. s 137 - 140
Larsen, Ann-Cecilie; Spyrou, Artemis; Liddick, Sean N. & Guttormsen, Magne Sveen (2019). Novel techniques for constraining neutron-capture rates relevant for r-process heavy-element nucleosynthesis. Progress in Particle and Nuclear Physics. ISSN 0146-6410. 107, s 69- 108 . doi: 10.1016/j.ppnp.2019.04.002 Full text in Research Archive.
Lewis, Rebecca; Liddick, Sean N.; Larsen, Ann-Cecilie; Spyrou, Artemis; Bleuel, Darren L.; Couture, Aaron J.; Crespo Campo, Lucia; Crider, Benjamin P.; Dombos, Alexander C.; Guttormsen, Magne Sveen; Mosby, Shea M.; Naqvi, Farheen; Perdikakis, George; Prokop, Christopher J.; Quinn, Stephen; Renstrøm, Therese & Siem, Sunniva (2019). Experimental constraints on the 73Zn(n,γ)74Zn reaction rate. Physical Review C. ISSN 2469-9985. 99(3) . doi: 10.1103/PhysRevC.99.034601 Full text in Research Archive.
Liddick, Sean N.; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Spyrou, Artemis; Crider, Benjamin P.; Naqvi, Farheen; Midtbø, Jørgen E.; Bello Garrote, Frank Leonel; Bleuel, Darren L.; Crespo Campo, Lucia; Couture, Aaron J.; Dombos, Alexander C.; Giacoppo, Francesca; Görgen, Andreas; Hadynska-Klek, Katarzyna; Hagen, Trine Wiborg; Ingeberg, Vetle Wegner; Kheswa, Bonginkosi Vincent; Lewis, Rebecca; Mosby, Shea M.; Perdikakis, Georgios; Prokop, Christopher J.; Quinn, Stephen; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva; Tveten, Gry Merete; Wiedeking, Mathis & Zeiser, Fabio (2019). Benchmarking the extraction of statistical neutron capture cross sections on short-lived nuclei for applications using the β-Oslo method. Physical Review C. ISSN 2469-9985. 100:024624(2), s 1- 12 . doi: 10.1103/PhysRevC.100.024624 Full text in Research Archive.
Lyons, Stephanie; Spyrou, Artemis; Liddick, Sean N.; Naqvi, Farheen; Crider, Benjamin P.; Dombos, Alexander C.; Bleuel, Darren L.; Brown, B. Alex; Couture, Aaron J.; Crespo Campo, Lucia; Engel, Jonathan; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Lewis, Rebecca; Möller, Peter M.; Mosby, Shea M.; Mumpower, Matthew R.; Ney, Evan M.; Palmisano, Alicia; Perdikakis, George; Prokop, Christopher J.; Renstrøm, Therese; Siem, Sunniva; Smith, Mallory K. & Quinn, Stephen J. (2019). 69,71Co β-decay strength distributions from total absorption spectroscopy. Physical Review C. ISSN 2469-9985. 100(2), s 1- 10 . doi: 10.1103/PhysRevC.100.025806 Full text in Research Archive.
Malatji, Kgashane Leroy; Wiedeking, Mathis; Goriely, Stephane; Brits, Christiaan Petrus; Kheswa, Bonginkosi Vincent; Bello Garrote, Frank Leonel; Bleuel, Darren L.; Giacoppo, Francesca; Görgen, Andreas; Guttormsen, Magne Sveen; Hadynska-Klek, Katarzyna; Hagen, Trine Wiborg; Ingeberg, Vetle Wegner; Klintefjord, Malin; Larsen, Ann-Cecilie; Papka, P.; Renstrøm, Therese; Sahin, Eda; Siem, Sunniva; Siess, L.; Tveten, Gry Merete & Zeiser, Fabio (2019). Re-estimation of 180Ta nucleosynthesis in light of newly constrained reaction rates. Physics Letters B. ISSN 0370-2693. 791, s 403- 408 . doi: 10.1016/j.physletb.2019.03.013 Full text in Research Archive.
Midtbø, Jørgen E.; Larsen, Ann-Cecilie; Renstrøm, Therese; Bello Garrote, Frank Leonel & Lima, Erlend (2019). Systematic Low-Energy Enhancementof the Gamma-Ray Strength Function, In Alba Formicola; Matthias Junker; Lucio Gialanella & Gianluca Imbriani (ed.), Nuclei in the Cosmos XV. Springer. ISBN 978-3-030-13875-2. 76. s 405 - 407
Utsunomiya, Hiroaki; Renstrøm, Therese; Tveten, Gry Merete; Goriely, Stéphane; Ari-izumi, Takashi; Filipescu, Dan Mihai; Kaur, Jagjot; Lui, Yiu-Wing; Luo, W.; Miyamoto, Shyuji; Larsen, Ann-Cecilie; Hilaire, Stéphane; Péru, Sophie & Koning, Arjan J. (2019). γ-ray strength function for thallium isotopes relevant to the 205Pb−205Tl chronometry. Physical Review C. ISSN 2469-9985. 99(2), s 024609-1- 023609-8 . doi: 10.1103/PhysRevC.99.024609 Full text in Research Archive.
Voinov, Alexander; Renstrøm, Therese; Bleuel, D.l.; Grimes, S.M.; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Liddick, Sean N.; Perdikakis, George; Spyrou, Artemis; Akhtar, S; Alanazi, N; Brandenburg, K; Brune, C.R.; Danley, T.W.; Dhakal, S.; Gastis, P.; Giri, R.; Massey, T.N.; Meisel, Z.; Nikas, S.; Paneru, S. N.; Parker, C.E. & Richard, A.L. (2019). Level densities of 74,76Ge from compound nuclear reactions. Physical Review C. ISSN 2469-9985. 99(5) . doi: 10.1103/PhysRevC.99.054609 Full text in Research Archive.
Zeiser, Fabio; Tveten, Gry Merete; Potel, Gregory; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Laplace, Thibault A.; Siem, Sunniva; Bleuel, Darren L.; Goldblum, Bethany L.; Bernstein, Lee A.; Bello Garrote, Frank Leonel; Crespo Campo, Lucia; Eriksen, Tomas Kvalheim; Görgen, Andreas; Hadynska-Klek, Katarzyna; Ingeberg, Vetle Wegner; Midtbø, Jørgen E.; Sahin, Eda; Tornyi, Tamas Gabor; Voinov, Alexander; Wiedeking, Mathis & Wilson, Jonathan (2019). Restricted spin-range correction in the Oslo method: The example of nuclear level density and γ-ray strength function from 239Pu(d, pγ) 240Pu. Physical Review C. ISSN 2469-9985. 100:024305(2), s 1- 9 . doi: 10.1103/PhysRevC.100.024305 Full text in Research Archive.
Crespo Campo, Lucia; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Görgen, Andreas; Hadynska-Klek, Katarzyna; Klintefjord, Malin; Larsen, Ann-Cecilie; Renstrøm, Therese; Sahin, Eda; Siem, Sunniva; Springer, A.; Tornyi, Tamas Gabor & Tveten, Gry Merete (2018). Test of the generalized Brink-Axel hypothesis in 64,65Ni. Physical Review C. ISSN 2469-9985. 98, s 054303-1- 054303-10 . doi: 10.1103/PhysRevC.98.054303 Full text in Research Archive. Show summary
Previously published particle-γ coincidence data on the 64Ni(p,p′γ)64Ni and 64Ni(d,pγ)65Ni reactions were further analyzed to study the statistical properties of γ decay in 64,65Ni. To do so, the γ decay to the quasicontinuum region and discrete low-lying states was investigated at γ-ray energies of 2.0–9.6 and 1.6–6.1 MeV in 64 Ni and 65 Ni, respectively. In particular, the dependence of the γ -strength function with initial and final excitation energy was studied to test the validity of the generalized Brink-Axel hypothesis. Finally, the role of fluctuations in transition strengths was estimated as a function of γ-ray and excitation energy. The γ -strength function is consistent with the hypothesis of the independence of initial excitation energy, in accordance with the generalized Brink-Axel hypothesis. The results show that the γ decay to low-lying levels displays large fluctuations for low initial excitation energies.
Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Midtbø, Jørgen E.; Crespo Campo, Lucia; Görgen, Andreas; Ingeberg, Vetle Wegner; Renstrøm, Therese; Siem, Sunniva; Tveten, Gry Merete; Zeiser, Fabio & Kirsch, Leo (2018). Gamma-widths, lifetimes and fluctuations in the nuclear quasi-continuum. The European Physical Journal Conferences. ISSN 2101-6275. 178(06001) . doi: 10.1051/epjconf/201817806001 Full text in Research Archive.
Jones, M.D.; Macchiavelli, Augusto Oswaldo; Wiedeking, Mathis; Bernstein, Lee A.; Crawford, Heather L.; Campbell, C.M.; Clark, Rod M.; Cromaz, Mario; Fallon, Paul; Lee, I-Yang; Salathe, M.; Wiens, Andreas; Ayangeakaa, A.D.; Bleuel, Darren L.; Bottoni, S.; Carpenter, M.P.; Davids, H.M.; Elson, J.; Görgen, Andreas; Guttormsen, Magne Sveen; Janssens, R.V.F.; Kinnison, J.E.; Kirsch, Leo; Larsen, Ann-Cecilie; Lauritsen, Torben; Reviol, Walter; Sarantites, Demetrios G.; Siem, Sunniva; Voinov, A.V. & Zhu, S. (2018). Examination of the Low-Energy Enhancement of the gamma-ray Strength Function of 56Fe. Physical Review C. ISSN 2469-9985. 97(2) . doi: 10.1103/PhysRevC.97.024327 Full text in Research Archive.
Larsen, Ann-Cecilie; Midtbø, Jørgen E.; Guttormsen, Magne Sveen; Renstrøm, Therese; Liddick, Sean N.; Spyrou, Artemis; Karampagia, Sofia; Brown, Alex; Achakovskiy, Oleg; Kamerdzhiev, Sergei; Bleuel, Darren L.; Couture, Aaron J.; Crespo Campo, Lucia; Crider, Benjamin P.; Dombos, Alexander C.; Lewis, Rebecca; Mosby, Shea M.; Naqvi, Farheen; Perdikakis, Georgios; Prokop, Christopher J.; Quinn, Stephen & Siem, Sunniva (2018). Enhanced low-energy γ-decay strength of 70Ni and its robustness within the shell model. Physical Review C. ISSN 2469-9985. 97(5), s 1- 9 . doi: 10.1103/PhysRevC.97.054329 Full text in Research Archive.
Midtbø, Jørgen E.; Larsen, Ann-Cecilie; Renstrøm, Therese; Bello Garrote, Frank Leonel & Lima, Erlend (2018). Consolidating the concept of low-energy magnetic dipole decay radiation. Physical Review C. ISSN 2469-9985. 98(6), s 064321-1- 064321-12 . doi: 10.1103/PhysRevC.98.064321 Full text in Research Archive.
Renstrøm, Therese; Utsunomiya, H.; Nyhus, Hilde-Therese; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Tveten, Gry Merete; Filipescu, D. M.; Gheorghe, I.; Goriely, S; Hilaire, S.; Lui, Y.-W.; Midtbø, Jørgen E.; Péru, S.; Shima, T.; Siem, Sunniva & Tesileanu, O. (2018). Verification of detailed balance for γ absorption and emission in Dy isotopes. Physical Review C. ISSN 2469-9985. 98(5), s 1- 14 . doi: 10.1103/PhysRevC.98.054310 Full text in Research Archive. Show summary
The photoneutron cross sections of 162,163Dy have been measured for the first time in an energy region from the neutron threshold (Sn) up to ≈13MeV. The (γ,n) reaction was induced with quasimonochromatic laser Compton-scattered γ rays, produced at the NewSUBARU laboratory. The corresponding γ -ray strength functions (γ SF) have been calculated from the photoneutron cross sections. The data are compared to reanalyzed γSFs of 160–164Dy, which are measured below Sn. The excellent agreement with the photoneutron data at Sn confirms the principle of detailed balance. Thus, a complete γ SF is established covering in total the energy regionof1 Eγ 13MeV.Thesemid-shellwell-deformeddysprosiumisotopesallshowscissorsresonances with very similar structures. We find that our data predict the same integrated scissors strength as (γ,γ′) data when integrated over the same energy range, which shows that the scissors mode very likely is consistent with the generalized Brink hypothesis. Finally, using the γSFs as input in the reaction code TALYS, we have deduced radiative neutron-capture cross sections and compared them to direct measurements. We find a very good agreement within the uncertainties, which gives further support to the experimentally determined γ SFs.
Utsunomiya, Hiroaki; Renstrøm, Therese; Tveten, Gry Merete; Gheorghe, Ioana; Filipescu, Dan Mihai; Belyshev, Sergey; Stopani, Konstantin; Wang, Hongwei; Fan, Gongtao; Lui, Yiu-Wing; Symochko, Dmytro; Goriely, Stephane; Larsen, Ann-Cecilie; Siem, Sunniva; Varlamov, Vladimir; Ishkhanov, Boris; Glodariu, Tudor; Krzysiek, Mateusz; Takenaka, Daiki; Ari-Izumi, Takashi; Amano, Sho & Miyamoto, Shuji (2018). Photoneutron Reaction Data for Nuclear Physics and Astrophysics. The European Physical Journal Conferences. ISSN 2101-6275. 178 . doi: 10.1051/epjconf/201817806003 Full text in Research Archive.
Utsunomiya, Hiroaki; Renstrøm, Therese; Tveten, Gry Merete; Goriely, Stéphane; Katayama, Seitaro; Ari-Izumi, Takashi; Takenaka, Daiki; Symochko, Dmytro; Kheswa, Bonginkosi Vincent; Ingeberg, Vetle Wegner; Glodariu, Tudor; Lui, Yiu-Wing; Miyamoto, Shyuji; Larsen, Ann-Cecilie; Midtbø, Jørgen E.; Görgen, Andreas; Siem, Sunniva; Crespo Campo, Lucia; Guttormsen, Magne Sveen; Hilaire, Stéphane; Péru, Sophie & Koning, Arjan J. (2018). Photoneutron cross sections for Ni isotopes: Toward understanding (n, γ ) cross sections relevant to weak s-process nucleosynthesis. Physical Review C. ISSN 2469-9985. 98(5), s 1- 9 . doi: 10.1103/PhysRevC.98.054619 Full text in Research Archive. Show summary
Photoneutron cross sections were measured for 58Ni, 60Ni, 61Ni, and 64Ni at energies between the one-neutron and two-neutron thresholds using quasimonochromatic γ -ray beams produced in laser Compton scattering at the NewSUBARU synchrotron radiation facility. These photoneutron data are used to extract the γ -ray strength function above the neutron threshold, complementing the information obtained by the Oslo method below the threshold. We discuss radiative neutron-capture cross sections and the Maxwellian-averaged cross sections for Ni isotopes including 63Ni, a branching point nucleus along the weak s-process path. The cross sections are calculated with the experimentally constrained γ-ray strength functions from the Hartree-Fock-Bogolyubov plus quasiparticle–random-phase approximation based on the Gogny D1M interaction for both E1 and M1 components and supplemented with the M1 upbend.
Brits, C.P.; Wiedeking, M.; Bello Garrote, Frank Leonel; Bleuel, D. L.; Giacoppo, F.; Görgen, Andreas; Guttormsen, Magne Sveen; Hadynska-Klek, Katarzyna; Hagen, Trine Wiborg; Ingeberg, Vetle Wegner; Kheswa, Bonginkosi Vincent; Klintefjord, Malin; Larsen, Ann-Cecilie; Malatji, Kgashane L.; Nyhus, Hilde-Therese; Papka, P; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva; Tveten, Gry Merete & Zeiser, Fabio (2017). Resonances in odd-odd 182Ta. The European Physical Journal Conferences. ISSN 2101-6275. 146 . doi: 10.1051/epjconf/201714605012 Full text in Research Archive.
Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Blasi, Nives; Bracco, Angela; Camera, Franco; Crespo Campo, Lucia; Eriksen, Tomas Kvalheim; Görgen, Andreas; Hagen, Trine Wiborg; Ingeberg, Vetle Wegner; Kheswa, Bonginkosi Vincent; Leoni, Silvia; Midtbø, Jørgen Eriksson; Million, Bénédicte; Nyhus, Hilde-Therese; Renstrøm, Therese; Rose, Sunniva Johanne; Ruud, Inger Eli; Siem, Sunniva; Tornyi, Tamas Gabor; Tveten, Gry Merete; Voinov, Alexander; Wiedeking, Mathis & Zeiser, Fabio (2017). Low-energy enhancement and fluctuations of γ-ray strength functions in 56,57Fe: test of the Brink–Axel hypothesis. Journal of Physics G: Nuclear and Particle Physics. ISSN 0954-3899. 44(6) . doi: 10.1088/1361-6471/aa644a Full text in Research Archive.
Crespo Campo, Lucia; Larsen, Ann-Cecilie; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Görgen, Andreas; Guttormsen, Magne Sveen; Klintefjord, Malin Linnea; Renstrøm, Therese; Sahin, Eda; Siem, Sunniva; Tornyi, Tamas Gabor & Tveten, Gry Merete (2017). Investigating the gamma decay of Ni 65 from particle-gamma coincidence data. Physical Review C. ISSN 2469-9985. 96(1) . doi: 10.1103/PhysRevC.96.014312 Full text in Research Archive.
Guttormsen, Magne Sveen; Goriely, Stephan; Larsen, Ann-Cecilie; Görgen, Andreas; Hagen, Trine Wiborg; Renstrøm, Therese; Siem, Sunniva; Syed, Naeem Ul Hasan; Tagliente, Giuseppe; Toft, Heidi Kristine; Utsunomiya, Hiroaki; Voinov, Alexander & Wikan, Kristine (2017). Quasicontinuum γ decay of 91,92Zr: Benchmarking indirect (n,γ ) cross section measurements for the s process. Physical Review C. ISSN 2469-9985. 96(2) . doi: 10.1103/PhysRevC.96.024313 Full text in Research Archive.
Kheswa, Bonginkosi Vincent; Wiedeking, Mathis; Brown, Joshua A.; Larsen, Ann-Cecilie; Goriely, Stéphane; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel; Bernstein, Lee A.; Bleuel, Darren L.; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Görgen, Andreas; Goldblum, Bethany L.; Hagen, Trine Wiborg; Koehler, Paul Edward; Klintefjord, Malin; Malatji, Kgashane L.; Midtbø, Jørgen Eriksson; Nyhus, Hilde-Therese; Papka, P.; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2017). 137,138,139La(n,γ) cross sections constrained with statistical decay properties of 138,139,140La nuclei. Physical Review C. ISSN 2469-9985. 95(4) . doi: 10.1103/PhysRevC.95.045805 Full text in Research Archive.
Larsen, Ann-Cecilie; Spyrou, Artemis; Liddick, Sean N.; Guttormsen, Magne Sveen; Ingeberg, Vetle Wegner; Siem, Sunniva; Wiedeking, Mathis; Crider, Benjamin P.; Naqvi, Farheen; Perdikakis, George; Mumpower, Matthew R.; Surman, Rebecca A.; Tveten, Gry Merete; Bleuel, Darren L.; Couture, Aaron J.; Crespo Campo, Lucia; Dombos, Alexander C.; Görgen, Andreas; Lewis, Rebecca; Mosby, Shea; Nikas, Stylianos; Prokop, Christopher; Quinn, Stephen; Renstrøm, Therese & Rubio, Berta (2017). Novel Techniques for Constraining Neutron-capture Rates relevant to Heavy-element Nucleosynthesis. PoS - Proceedings of Science. ISSN 1824-8039. INPC2016 . doi: 10.22323/1.281.0360 Full text in Research Archive.
Malatji, Kgashane L.; Kheswa, Bonginkosi Vincent; Wiedeking, M.; Bello Garrote, Frank Leonel; Brits, C.P.; Bleuel, D. L.; Giacoppo, Francesca; Görgen, Andreas; Guttormsen, Magne Sveen; Hadynska-Klek, Katarzyna; Hagen, Trine Wiborg; Ingeberg, Vetle Wegner; Klintefjord, Malin; Larsen, Ann-Cecilie; Nyhus, Hilde-Therese; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva; Tveten, Gry Merete & Zeiser, Fabio (2017). Nuclear level densities and γ-ray strength functions of 180,181Ta and neutron capture cross sections. The European Physical Journal Conferences. ISSN 2101-6275. 146 . doi: 10.1051/epjconf/201714601010 Full text in Research Archive.
Rose, Sunniva Johanne; Zeiser, Fabio; Wilson, JN; Oberstedt, A; Oberstedt, S; Siem, Sunniva; Tveten, Gry Merete; Bernstein, LA; Bleuel, DL; Brown, JA; Crespo Campo, Lucia; Giacoppo, Francesca; Görgen, Andreas; Guttormsen, Magne Sveen; Hadynska-Klek, Katarzyna; Hafreager, Anders; Hagen, Trine Wiborg; Klintefjord, Malin Linnea; Laplace, TA; Larsen, Ann-Cecilie; Renstrøm, Therese; Sahin, Eda; Schmitt, C; Tornyi, Tamas Gabor & Wiedeking, M (2017). Energy dependence of the prompt gamma-ray emission from the (d,p)-induced fission of U-234 and Pu-240. Physical Review C. ISSN 2469-9985. 96(1) . doi: 10.1103/PhysRevC.96.014601 Full text in Research Archive.
Spyrou, Artemis; Larsen, Ann-Cecilie; Liddick, Sean N.; Naqvi, Farheen; Crider, Benjamin P.; Dombos, Alexander C.; Guttormsen, Magne Sveen; Bleuel, Darren L.; Couture, Aaron J.; Crespo Campo, Lucia; Lewis, Rebecca; Mosby, Shea; Mumpower, Matthew R.; Perdikakis, George; Prokop, Christopher; Quinn, Stephen; Renstrøm, Therese; Siem, Sunniva & Surman, Rebecca A. (2017). Neutron-capture rates for explosive nucleosynthesis: the case of 68Ni(n, γ)69Ni. Journal of Physics G: Nuclear and Particle Physics. ISSN 0954-3899. 44 . doi: 10.1088/1361-6471/aa5ae7 Full text in Research Archive.
Tveten, Gry Merete; Spyrou, Artemis; Schwengner, Ronald; Naqvi, Farheen; Larsen, Ann-Cecilie; Renstrøm, Therese; Eriksen, Tomas Kvalheim; Bello Garrote, Frank Leonel; Bernstein, Lee A.; Bleuel, Darren L.; Crespo Campo, Lucia; Guttormsen, Magne Sveen; Giacoppo, Francesca; Görgen, Andreas; Hagen, Trine Wiborg; Hadynska-Klek, Katarzyna; Klintefjord, Malin; meyer, b. s.; Nyhus, Hilde-Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2017). The Statistical Properties Of 92Mo And Implications For The p-process. PoS - Proceedings of Science. ISSN 1824-8039. INPC2016 Full text in Research Archive. Show summary
A particularly challenging part of the question of how elements heavier than iron are created in extreme, astrophysical environments is the creation of the so-called p-nuclei, which are believed to be mainly produced in the O-Ne layer of type II supernovae or type Ia supernovae. The lack of needed nuclear data presents an obstacle in nailing down the precise site and astrophysical conditions for the production of these isotopes. Astrophysical model calculations are able to reproduce abundance patterns of most p-isotopes reasonably well, with some pivotal exceptions. In particular, p-isotopes of mass 92 ≤ A ≤ 98 are underproduced in calculations compared to the actual abundance of these isotopes. The p-isotope 92Mo represents one of the most severe cases of underproduction. State-of-the-art p-process calculations systematically underestimate the observed solar abundance of this isotope. The main destruction mechanism of this isotope in the standard description of the p-process is through the 92Mo(γ, p)91Nb reaction. Measurements on the nuclear level density and average gamma strength function of 92Mo have been carried out at the Oslo Cyclotron Laboratory. TALYS cross section and reaction rate calculations where the experimental results are used as input will be presented. The data provide stringent constraints on the 91Nb(p, γ)92Mo (and consequently the inverse) reaction rate. The reaction rate extracted in this work was used in reaction network calculations for the scenario of a p-process taking place in a type II supernova explosion as the shock front passes through the O-Ne layer of a 25 solar mass star.
Wiedeking, Mathis; Bernstein, Lee A.; Bleuel, Darren L.; Brits, Christiaan Petrus; Sowazi, Khanyisa; Görgen, Andreas; Goldblum, Bethany L.; Guttormsen, Magne Sveen; Kheswa, Bonginkosi Vincent; Larsen, Ann-Cecilie; Majola, Siyabonga N.T.; Malatji, Kgashane Leroy; Negi, Dinesh; Nogwanya, Thembalethu; Siem, Sunniva & Zikhali, Bonginkosi Richard (2017). Statistical gamma-ray decay studies at iThemba LABS. The European Physical Journal Conferences. ISSN 2101-6275. 146:05006, s 1- 4 . doi: 10.1051/epjconf/201714605006
Ay, K.o.; Ozgur, Mustafa; Algin, Emel; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel; Crespo Campo, Lucia; Görgen, Andreas; Hagen, Trine Wiborg; Ingeberg, Vetle Wegner; Kheswa, Bonginkosi Vincent; Klintefjord, Malin; Larsen, Ann-Cecilie; Midtbø, Jørgen Eriksson; Modamio, Victor Høybjør; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva; Tveten, Gry Merete & Zeiser, Fabio (2016). Nuclear level densities and gamma-ray strength functions of 145,149,151Nd isotopes. Journal of Physics: Conference Series (JPCS). ISSN 1742-6588. 766(012027) . doi: 10.1088/1742-6596/766/1/012027
Clement, E; Zielinska, Magdalena; Péru, Sophie; Goutte, Héloïse; Hilaire, Stephane; Görgen, Andreas; Korten, Wolfram; Doherty, Daniel T.; Bastin, Beyhan; Bauer, C; Blazhev, A; Bree, N; Bruyneel, Bart; Butler, Peter A.; Butterworth, J; Cederkall, Joakim; Delahaye, P; Dijon, Aurore; Ekstrom, A; Fitzpatrick, C; Fransen, C.; Georgiev, Georgi; Gernhauser, Roman; Hess, H; Iwanicki, J.; Jenkins, David G.; Larsen, Ann-Cecilie; Ljungvall, Joa; Lutter, R; Marley, P.; Moschner, K.; Napiorkowski, P. J.; Pakarinen, J.; Petts, A; Reiter, Peter; Renstrøm, Therese; Seidlitz, M; Siebeck, B.; Siem, Sunniva; Sotty, Christophe; Srebrny, Julian; Stefanescu, I.; Tveten, Gry Merete; Van de Walle, Jarno; Vermeulen, M; Voulot, Didier; Warr, Nigel; Wenander, Fredrik; Wiens, Andreas; De Witte, H. & Wrzosek, K. (2016). Low-energy Coulomb excitation of 96,98Sr beams. Physical Review C. Nuclear Physics. ISSN 0556-2813. 94(5) . doi: 10.1103/PhysRevC.94.054326 Full text in Research Archive.
Clément, Emmanuel; Zielińska, Magdalena; Görgen, Andreas; Körten, Wolfram; Péru, Sophie; Libert, Jacques J.; Goutte, Héloïse; Hilaire, Stéphane; Bastin, Beyhan; Bauer, Clemens; Blazhev, Andrey; Bree, Nick; Bruyneel, Bart; Butler, Peter A.; Butterworth, James E.; Delahaye, Pierre; Dijon, Aurore; Doherty, Daniel T.; Ekström, Andreas; Fitzpatrick, Conor; Fransen, Christoph; Georgiev, Georgi; Gernhäuser, ROMAN; Hess, Herbert; Iwanicki, Jêdrzej; Jenkins, David G.; Larsen, Ann-Cecilie; Ljungvall, Joa; Lutter, Rudolph; Marley, P.; Moschner, Kevin; Napiorkowski, Paweł Jan; Pakarinen, Janne A.; Petts, Andrew; Reiter, Peter; Renstrøm, Therese; Seidlitz, Michael; Siebeck, Burkhard; Siem, Sunniva; Sotty, Christophe; Srebrny, Julian; Ştefǎnescu, Ioan; Tveten, Gry Merete; Van De Walle, Jean V.; Vermeulen, Martien J.W.; Voulot, Didier; Warr, Nigel V.; Wenander, Fredrik; Wiens, Andreas; De Witte, Hans & Wrzosek-Lipska, Katarzyna (2016). Spectroscopic Quadrupole Moments in Sr 96,98: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60. Physical Review Letters. ISSN 0031-9007. 116:022701(2) . doi: 10.1103/PhysRevLett.116.022701 Full text in Research Archive.
Crespo Campo, Lucia; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Görgen, Andreas; Guttormsen, Magne Sveen; Hadynska-Klek, Katarzyna; Klintefjord, Malin; Larsen, Ann-Cecilie; Renstrøm, Therese; Sahin, Eda; Siem, Sunniva; Springer, A; Tornyi, Tamas Gabor & Tveten, Gry Merete (2016). Statistical γ -decay properties of Ni 64 and deduced (n,γ) cross section of the s -process branch-point nucleus Ni 63. Physical Review C. Nuclear Physics. ISSN 0556-2813. 94(4) . doi: 10.1103/PhysRevC.94.044321 Full text in Research Archive.
Ducasse, Q; Jurado, B; Aiche, M; Marini, P; Mathieu, L; Görgen, Andreas; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Tornyi, Tamas Gabor; Wilson, JN; Barreau, G; Boutoux, G; Czajkowski, S; Giacoppo, Francesca; Gunsing, F; Hagen, Trine Wiborg; Lebois, M; Lei, J; Meot, V; Morillon, B; Moro, AM; Renstrøm, Therese; Roig, O; Rose, Sunniva Johanne; Serot, O; Siem, Sunniva; Tsekhanovich, I; Tveten, Gry Merete & Wiedeking, M (2016). Investigation of the U 238 (d,p) surrogate reaction via the simultaneous measurement of γ -decay and fission probabilities. Physical Review C. Nuclear Physics. ISSN 0556-2813. 94(2) . doi: 10.1103/PhysRevC.94.024614 Full text in Research Archive.
Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Görgen, Andreas; Renstrøm, Therese; Siem, Sunniva; Tornyi, Tamas Gabor & Tveten, Gry Merete (2016). Is the generalized Brink-Axel hypothesis valid?. PoS - Proceedings of Science. ISSN 1824-8039. 2016-September, s 1- 8 . doi: 10.22323/1.281.0062 Full text in Research Archive.
Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Görgen, Andreas; Renstrøm, Therese; Siem, Sunniva; Tornyi, Tamas Gabor & Tveten, Gry Merete (2016). Validity of the Generalized Brink-Axel Hypothesis in Np 238. Physical Review Letters. ISSN 0031-9007. 116(1) . doi: 10.1103/PhysRevLett.116.012502 Full text in Research Archive.
Klintefjord, Malin; Hadynska-Klek, Katarzyna; Görgen, Andreas; Bauer, C; Bello Garrote, Frank Leonel; Bönig, S; Bounthong, B; Damyanova, A; Delaroche, Jean Paul; Fedosseev, V; Fink, D. A.; Giacoppo, Francesca; Girod, M; Hoff, Per; Imai, N; Korten, Wolfram; Larsen, Ann-Cecilie; Libert, J; Lutter, R; Marsh, B. A.; Molkanov, P. L.; Naïdja, Houda; Napiorkowski, P; Nowacki, F; Pakarinen, J; Rapisarda, E; Reiter, P; Renstrøm, Therese; Rothe, S; Seliverstov, M. D.; Siebeck, B; Siem, Sunniva; Srebrny, Julian; Stora, T; Thöle, P; Tornyi, Tamas Gabor; Tveten, Gry Merete; Van Duppen, P; Vermeulen, MJ; Voulot, D; Warr, Nigel; Wenander, F; De Witte, H & Zielinska, M (2016). Structure of low-lying states in Sm140 studied by Coulomb excitation. Physical Review C. Nuclear Physics. ISSN 0556-2813. 93(5) . doi: 10.1103/PhysRevC.93.054303
Laplace, Thibault A.; Zeiser, Fabio; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Bleuel, Darren L.; Bernstein, Lee A.; Goldblum, Bethany L.; Siem, Sunniva; Bello Garrote, Frank Leonel; Brown, Joshua A.; Crespo Campo, Lucia; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Gorgen, Andreas; Hadynska-Klek, Katarzyna; Henderson, Roger A.; Klintefjord, Malin; Lebois, Matthieu; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Tornyi, Tamas Gabor; Tveten, Gry Merete; Voinov, Alexander; Wiedeking, Mathis; Wilson, Jonathan & Younes, Walid (2016). Statistical properties of Pu 243, and Pu 242 (n,γ) cross section calculation. Physical Review C. Nuclear Physics. ISSN 0556-2813. 93(1) . doi: 10.1103/PhysRevC.93.014323 Full text in Research Archive.
Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Schwengner, Ronald; Bleuel, Darren L.; Goriely, Stephane; Harrisopulos, Sotirios; Bello Garrote, Frank Leonel; Byun, Y.; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Görgen, Andreas; Hagen, Trine Wiborg; Klintefjord, Malin; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva; Tornyi, Tamas Gabor; Tveten, Gry Merete; Voinov, Alexander & Wiedeking, Mathis (2016). Experimentally constrained (p,γ) y 89 and (n,γ) y 89 reaction rates relevant to p -process nucleosynthesis. Physical Review C. Nuclear Physics. ISSN 0556-2813. 93(4) . doi: 10.1103/PhysRevC.93.045810 Full text in Research Archive.
Larsen, Ann-Cecilie; Spyrou, Artemisia; Liddick, Sean N.; Guttormsen, Magne Sveen; Ingeberg, Vetle Wegner; Siem, Sunniva; Wiedeking, Mathis; Crider, Benjamin P.; Naqvi, Farheen; Perdikakis, Georgios; Mumpower, Matthew R.; Surman, Rebecca A.; Tveten, Gry Merete; Bleuel, Darren L.; Couture, Aaron J.; Crespo Campo, Lucia; Dombos, Alexander C.; Görgen, Andreas; Lewis, Raymond A.; Mosby, Shea M.; Nikas, Stylianos; Prokop, Christopher J.; Quinn, Simon J.; Renstrøm, Therese & Rubio, Berta (2016). Novel techniques for constraining neutron-capture rates relevant to heavy-element nucleosynthesis. PoS - Proceedings of Science. ISSN 1824-8039. 2016-September:360, s 1- 9 Full text in Research Archive.
Liddick, Sean N.; Spyrou, Artemisia; Crider, Benjamin P.; Naqvi, Farheen; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Mumpower, Matthew R.; Surman, Rebecca A.; Perdikakis, Georgios; Bleuel, Darren L.; Couture, Aaron J.; Crespo Campo, Lucia; Dombos, Alexander C.; Lewis, Rob; Mosby, Shea; Nikas, Stylianos; Prokop, Christopher; Renstrøm, Therese; Rubio, Berta; Siem, Sunniva & Quinn, Simon J. (2016). Experimental Neutron Capture Rate Constraint Far from Stability. Physical Review Letters. ISSN 0031-9007. 116:242502(24) . doi: 10.1103/PhysRevLett.116.242502 Full text in Research Archive.
Marini, P.; Ducasse, Q; Jurado, B; Aiche, M; Mathieu, L; Barreau, G.; Czajkowski, S; Tsekhanovich, I; Moro, A; Lei, J; Giacoppo, Francesca; Görgen, Andreas; Tornyi, Tamas Gabor; Audouin, L; Tassan-Got, L; Wilson, J. N.; Gunsing, F.; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Lebois, M; Renstrøm, Therese; Rose, Sunniva Johanne; Siem, Sunniva; Tveten, Gry Merete; Wiedeking, M.; Serot, O; Boutoux, G; Meot, V; Morillon, B; Denis-Petit, D; Roig, O; Oberstedt, S & Oberstedt, A (2016). First simultaneous measurement of fission and gamma probabilities of <sup>237</sup>U and <sup>239</sup>Np via surrogate reactions. The European Physical Journal Conferences. ISSN 2101-6275. 122 . doi: 10.1051/epjconf/201612212004
Negi, D; Wiedeking, M; Lanza, EG; Litvinova, E; Vitturi, A; Bark, RA; Bernstein, LA; Bleuel, DL; Bvumbi, S; Bucher, TD; Daub, BH; Dinoko, TS; Easton, JL; Görgen, Andreas; Guttormsen, Magne Sveen; Jones, P; Kheswa, BV; Khumalo, NA; Larsen, Ann-Cecilie; Lawrie, EA; Lawrie, JJ; Majola, SNT; Masiteng, LP; Nchodu, MR; Ndayishimye, J; Newman, RT; Noncolela, SP; Orce, JN; Papka, P; Pellegri, L; Renstrøm, Therese; Roux, DG; Schwengner, R; Shirinda, O & Siem, Sunniva (2016). Nature of low-lying electric dipole resonance excitations in Ge 74. Physical Review C. Nuclear Physics. ISSN 0556-2813. 94(2) . doi: 10.1103/PhysRevC.94.024332 Full text in Research Archive.
Renstrøm, Therese; Nyhus, Hilde-Therese; Utsunomiya, Hiroaki; Schwengner, Ronald; Goriely, Stephane; Larsen, Ann-Cecilie; Filipescu, Dan Mihai; Gheorghe, Ioana; Bernstein, L. A.; Bleuel, Darren L.; Glodariu, T.; Görgen, Andreas; Guttormsen, Magne Sveen; Hagen, Trine Wiborg; Kheswa, Bonginkosi Vincent; Lui, Y.-W.; Negi, Dinesh; Ruud, Inger Eli; Shima, T.; Siem, Sunniva; Takahisa, K.; Tesileanu, O.; Tornyi, Tamas Gabor; Tveten, Gry Merete & Wiedeking, Mathis (2016). Low-energy enhancement in the γ-ray strength functions of Ge73,74. Physical Review C. Nuclear Physics. ISSN 0556-2813. 93(6) . doi: 10.1103/PhysRevC.93.064302 Full text in Research Archive.
Simon, Anna; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Beausang, Con W.; Humby, Peter; Burke, Jason T.; Casperson, Robert J.; Hughes, R.O.; Ross, Tim J.; Allmond, James Mitchell; Chyzh, R.; Dag, M.; Koglin, Jason M.; McCleskey, E.; McCleskey, Matt; Ota, Shuya & Saastamoinen, Antti (2016). First observation of low-energy γ -ray enhancement in the rare-earth region. Physical Review C. Nuclear Physics. ISSN 0556-2813. 93:034303 . doi: 10.1103/PhysRevC.93.034303 Full text in Research Archive.
Spyrou, Artemis; Liddick, Sean N.; Naqvi, Farheen; Crider, Benjamin P.; Dombos, Alexander C.; Bleuel, Darren L.; Brown, B.Alex; Couture, Aaron J.; Crespo Campo, Lucia; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Lewis, Rebecca; Möller, P.; Mosby, Shea; Mumpower, Matthew R.; Perdikakis, Georgios; Prokop, C. J.; Renstrøm, Therese; Siem, Sunniva; Quinn, S. J. & Valenta, S (2016). Strong Neutron-γ Competition above the Neutron Threshold in the Decay of 70Co. Physical Review Letters. ISSN 0031-9007. 117(14) . doi: 10.1103/PhysRevLett.117.142701 Full text in Research Archive.
Tveten, Gry Merete; Spyrou, A; Schwengner, R; Naqvi, F; Larsen, Ann-Cecilie; Eriksen, Tomas Kvalheim; Bello Garrote, Frank Leonel; Bernstein, LA; Bleuel, DL; Crespo Campo, Lucia; Guttormsen, Magne Sveen; Giacoppo, Francesca; Görgen, Andreas; Hagen, Trine Wiborg; Hadynska-Klek, Katarzyna; Klintefjord, Malin; Meyer, BS; Nyhus, Hilde-Therese; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2016). Completing the nuclear reaction puzzle of the nucleosynthesis of Mo 92. Physical Review C. Nuclear Physics. ISSN 0556-2813. 94(2) . doi: 10.1103/PhysRevC.94.025804 Full text in Research Archive.
Tveten, Gry Merete; Spyrou, Artemis; Schwengner, Ronald; Naqvi, Farheen; Larsen, Ann-Cecilie; Renstrøm, Therese; Eriksen, Tomas Kvalheim; Bello Garrote, Frank Leonel; Bernstein, Lee A.; Bleuel, Darren L.; Crespo Campo, Lucia; Guttormsen, Magne Sveen; Giacoppo, Francesca; Görgen, Andreas; Hagen, Trine Wiborg; Hadynska-Klek, Katarzyna; Klintefjord, Malin; Meyer, Bradley S.; Nyhus, Hilde-Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2016). The statistical properties of 92Mo and implications for the p-process. PoS - Proceedings of Science. ISSN 1824-8039. 2016-September:163
Wiedeking, Mathis; Krtička, M.; Bernstein, L. A.; Allmond, J. M.; Basunia, M. S.; Bleuel, Darren L.; Burke, J. T.; Daub, B. H.; Fallon, Paul; Firestone, R.B.; Goldblum, Bethany L.; Hatarik, R.; Lake, P. T.; Larsen, Ann-Cecilie; Lee, I.-Y.; Lescher, S. R.; Paschalis, S.; Petri, M.; Phair, L.; Scielzo, N. D. & Volya, A. (2016). γ-ray decay from neutron-bound and unbound states in Mo 95 and a novel technique for spin determination. Physical Review C. Nuclear Physics. ISSN 0556-2813. 93(2) . doi: 10.1103/PhysRevC.93.024303 Full text in Research Archive.
Bello Garrote, Frank Leonel; Görgen, Andreas; Mierzejewski, Jan; Mihai, Corina Mihaela; Delaroche, Jean Paul; Girod, Michel; Libert, Jacques J.; Sahin, Eda; Srebrny, Julian; Abraham, Theodore J.; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Hagen, Trine Wiborg; Kisieliński, Maciej; Klintefjord, Malin; Komorowska, Małgorzata; Kowalczyk, Maciej; Larsen, Ann-Cecilie; Marchlewski, Tomasz; Mitu, Iani Octavian; Pascu, Sorin; Siem, Sunniva; Stolarz, Anna & Tornyi, Tamas Gabor (2015). Lifetime measurement for the 21+ state in Sm 140 and the onset of collectivity in neutron-deficient Sm isotopes. Physical Review C. Nuclear Physics. ISSN 0556-2813. 92:024317(2) . doi: 10.1103/PhysRevC.92.024317 Full text in Research Archive.
Giacoppo, Francesca; Bello Garrote, Frank Leonel; Bernstein, Lee; Bleuel, D.l.; Firestone, R.B.; Görgen, Andreas; Guttormsen, Magne Sveen; Hagen, Trine Wiborg; Klintefjord, Malin; Koehler, Paul Edward; Larsen, Ann-Cecilie; Nyhus, Hilde-Therese; Renstrøm, Therese; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2015). Gamma decay from the quasicontinuum of 197,198Au. Physical Review C. Nuclear Physics. ISSN 0556-2813. 91 . doi: 10.1103/PhysRevC.91.054327 Full text in Research Archive.
Giacoppo, Francesca; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Görgen, Andreas; Guttormsen, Magne Sveen; Hagen, Trine Wiborg; Larsen, Ann-Cecilie; Kheswa, Bonginkosi Vincent; Klintefjord, Malin; Koehler, Paul Edward; Moretto, Luciano; Nyhus, Hilde-Therese; Renstrøm, Therese; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2015). Observation of low-lying resonances in the quasicontinuum of Pt-195,Pt-196 and enhanced astrophysical reaction rates. The European Physical Journal Conferences. ISSN 2101-6275. 93 . doi: 10.1051/epjconf/20159301039
Guttormsen, Magne Sveen; Aiche, M; Bello Garrote, Frank Leonel; Bernstein, Lee; Bleuel, D.l.; Byun, Y.; Ducasse, Q; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Görgen, Andreas; Gunsing, Frank; Hagen, Trine Wiborg; Jurado, B; Klintefjord, Malin; Larsen, Ann-Cecilie; Lebois, L.; Leniau, Baptist; Nyhus, Hilde-Therese; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva; Tornyi, Tamas Gabor; Tveten, Gry Merete; Voinov, Alexander; Wiedeking, Mathis & Wilson, Jonathan (2015). Experimental level densities of atomic nuclei. European Physical Journal A. ISSN 1434-6001. 51(12), s 1- 8 . doi: 10.1140/epja/i2015-15170-4
Kheswa, Bonginkosi Vincent; Wiedeking, Mathis; Giacoppo, Francesca; Goriely, Stephan; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Görgen, Andreas; Hagen, Trine Wiborg; Koehler, Paul Edward; Klintefjord, Malin; Nyhus, Hilde-Therese; Papka, P.; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2015). Galactic production of 138La: Impact of 138,139La statistical properties. Physics Letters B. ISSN 0370-2693. 744, s 268- 272 . doi: 10.1016/j.physletb.2015.03.065 Full text in Research Archive.
Kheswa, Bonginkosi Vincent; Wiedeking, Mathis; Giacoppo, Francesca; Goriely, Stephane; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Görgen, Andreas; Hagen, Trine Wiborg; Koehler, Paul Edward; Klintefjord, Malin; Nyhus, Hilde-Therese; Papka, P.; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2015). Statistical nuclear properties and synthesis of La-138. The European Physical Journal Conferences. ISSN 2101-6275. 93 . doi: 10.1051/epjconf/20159304005
Klintefjord, Malin; Hadynska-Klek, Katarzyna; Samorajczyk, J; Görgen, Andreas; Droste, C; Srebrny, J; Abraham, T; Bauer, C; Bello Garrote, Frank Leonel; Bönig, S; Damyanova, A; Giacoppo, Francesca; Grodner, E; Hoff, Per; Kisielinski, M; Komorowska, M; Korten, W; Kowalczyk, M; Kownacki, J; Larsen, Ann-Cecilie; Lutter, R; Marchlewski, T; Napiorkowski, P; Pakarinen, J; Rapisarda, E; Reiter, P; Renstrøm, Therese; Siebeck, B; Siem, Sunniva; Stolarz, A; Szenborn, R; Thöle, P; Tornyi, Tamas Gabor; Tucholski, A; Tveten, Gry Merete; Van Duppen, P; Vermeulen, MJ; Warr, N; De Witte, H & Zielinska, M (2015). Spectroscopy of low-lying states in 140Sm. Acta Physica Polonica B. ISSN 0587-4254. 46(3), s 607- 611 . doi: 10.5506/APhysPolB.46.607

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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 (2020). 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; Renstrøm, Therese; Siem, Sunniva; Tveten, Gry Merete; Zeiser, Fabio & Kirsch, Leo (2017). Gamma-widths, lifetimes and fluctuations in the nuclear quasi-continuum.
Larsen, Ann-Cecilie (2017, 30. desember). Alkymisten. Magasinet, Dagbladet.
Larsen, Ann-Cecilie (2017). Stjernestøv, supernovaer og atomkjerner – hvordan ble grunnstoffene til?.
Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Görgen, Andreas; Renstrøm, Therese; Siem, Sunniva; Tornyi, Tamas Gabor & Tveten, Gry Merete (2016). Is the generalized Brink-Axel hypothesis valid?.
Larsen, Ann-Cecilie (2016). Experimental level densities and gamma strength functions for nuclear astrophysics.
Larsen, Ann-Cecilie (2016). Novel techniques for constraining neutron-capture rates relevant to heavy-element nucleosynthesis.
Larsen, Ann-Cecilie (2016, 17. juni). Paneldeltager Abels tårn, Ekko P2. [Radio]. Realfagsbiblioteket, UiO.
Larsen, Ann-Cecilie (2016, 30. september). Programdeltagelse, Abels tårn. [Radio]. Radio, nettradio (NRK P2).
Tveten, Gry Merete; Spyrou, Artemis; Schwengner, Ronald; Naqvi, Farheen; Larsen, Ann-Cecilie; Eriksen, Tomas Kvalheim; Bello Garrote, Frank Leonel; Bernstein, Lee A.; Bleuel, Darren L.; Crespo Campo, Lucia; Guttormsen, Magne Sveen; Giacoppo, Francesca; Görgen, Andreas; Hagen, Trine Wiborg; Hadynska-Klek, Katarzyna; Klintefjord, Malin; meyer, b. s.; Nyhus, Hilde-Therese; Renstrøm, Therese; Rose, Sunniva Johanne; Sahin, Eda; Siem, Sunniva & Tornyi, Tamas Gabor (2016). The Statistical Properties Of 92Mo And Implications For The p-process. Show summary
A particularly challenging part of the question of how elements heavier than iron are created in extreme, astrophysical environments is the creation of the so-called p-nuclei, which are believed to be mainly produced in the O-Ne layer of type II supernovae or type Ia supernovae. The lack of needed nuclear data presents an obstacle in nailing down the precise site and astrophysical conditions for the production of these isotopes. Astrophysical model calculations are able to reproduce abundance patterns of most p-isotopes reasonably well, with some pivotal exceptions. In particular, p-isotopes of mass 92 ≤ A ≤ 98 are underproduced in calculations compared to the actual abundance of these isotopes. The p-isotope 92Mo represents one of the most severe cases of underproduction. State-of-the-art p-process calculations systematically underestimate the observed solar abundance of this isotope. The main destruction mechanism of this isotope in the standard description of the p-process is through the 92Mo(γ, p)91Nb reaction. Measurements on the nuclear level density and average gamma strength function of 92Mo have been carried out at the Oslo Cyclotron Laboratory. TALYS cross section and reaction rate calculations where the experimental results are used as input will be presented. The data provide stringent constraints on the 91Nb(p, γ)92Mo (and consequently the inverse) reaction rate. The reaction rate extracted in this work was used in reaction network calculations for the scenario of a p-process taking place in a type II supernova explosion as the shock front passes through the O-Ne layer of a 25 solar mass star.
Larsen, Ann-Cecilie (2015). A non-dark matter mystery: the quest for the origin of heavy elements.
Larsen, Ann-Cecilie (2015). A non-dark matter mystery: the quest for the origin of heavy elements.
Larsen, Ann-Cecilie (2015, 27. februar). Abels tårn - Ekko NRK P2. [Radio]. Realfagsbiblioteket, Vilhelm Bjerknes hus.
Larsen, Ann-Cecilie (2015). Applying for an ERC Starting Grant - some experiences and thoughts.
Larsen, Ann-Cecilie (2015). ERC Starting Grant 2015-2020: Resonant Nuclear Gamma Decay and the Heavy-Element Nucleosynthesis.
Larsen, Ann-Cecilie (2015). Enhanced low-energy gamma-decay probability – implications for r-process (n,gamma) reaction rates.
Larsen, Ann-Cecilie (2015). Galactic chemical evolution models for the Re-Os cosmochronology.
Larsen, Ann-Cecilie (2015). Heavy-element nucleosynthesis: astrophysics and nuclear-physics challenges.
Larsen, Ann-Cecilie (2015). Heavy-element nucleosynthesis: astrophysics and nuclear-physics challenges.
Larsen, Ann-Cecilie (2015). In search for the origin of heavy elements:  astrophysics and nuclear physics challenges.
Larsen, Ann-Cecilie (2015). Litt om meg, og kjernefysikk, og astrofysikk og sånn....
Larsen, Ann-Cecilie (2015). Low-energy enhancements in the nuclear gamma-decay strength - status, perspectives, and consequences for astrophysical (n,gamma) rates.
Larsen, Ann-Cecilie (2015). Min vei til et ERC Starting Grant - personlige erfaringer og tanker.

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

Projects

Resonant Nuclear Gamma Decay and the Heavy-Element Nucleosynthesis (gResonant)

Research groups

Nuclear and Energy Physics