Magne Guttormsen

• Naqvi, F.; Crespo Campo, Lucia; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Renstrøm, Therese & Siem, Sunniva [Vis alle 7 forfattere av denne artikkelen] (2022). Total absorption spectroscopy measurement on neutron-rich 74,75Cu isotopes. Nuclear Physics A. ISSN 0375-9474. A1018(122359). doi: 10.1016/j.nuclphysa.2021.122359.
• Gjestvang, Dorthea; Siem, Sunniva; Zeiser, Fabio; Randrup, Jørgen; Vogt, Ramona & Bello Garrote, Frank Leonel [Vis alle 20 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Markova, Maria; von Neumann-Cosel, Neumann-Cosel; Larsen, A.C.; Bassauer, S.; Görgen, A. & Guttormsen, Magne Sveen [Vis alle 25 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Wiedeking, Mathis; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Zeiser, Fabio; Görgen, Andreas & Liddick, Sean N. [Vis alle 9 forfattere av denne artikkelen] (2021). Independent normalization for gamma-ray strength functions: The shape method. Physical Review C. ISSN 2469-9985. 104(014311). doi: 10.1103/PhysRevC.104.014311. Fulltekst i vitenarkiv
• Persch, C.F.; DeYoung, P.A.; Lyons, S.; Spyrou, Artemis; Liddick, Sean N. & Naqvi, F. [Vis alle 27 forfattere av denne artikkelen] (2021). Beta-decay feeding intensity distributions of 71,73Ni. Physical Review C. ISSN 2469-9985. C103(055808). doi: 10.1103/PhysRevC.103.055808. Fulltekst i vitenarkiv
• Görgen, Andreas; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Siem, Sunniva; Adli, Erik & Edin, Nina Frederike J [Vis alle 14 forfattere av denne artikkelen] (2021). The Oslo Cyclotron Laboratory. The European Physical Journal Plus. ISSN 2190-5444. 136, s. 1–13. doi: 10.1140/epjp/s13360-021-01150-3. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Alhassid, Yoram; Ryssens, Wouter; Ay, K.o.; Ozgur, Mustafa & Algin, Emel [Vis alle 22 forfattere av denne artikkelen] (2021). Strong enhancement of level densities in the crossover from spherical to deformed neodymium isotopes. Physics Letters B. ISSN 0370-2693. 816. doi: 10.1016/j.physletb.2021.136206. Fulltekst i vitenarkiv
• Gjestvang, Dorthea; Siem, Sunniva; Zeiser, Fabio; Randrup, Jørgen; Vogt, Ramona & Wilson, Jonathan Nicholas [Vis alle 19 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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

• Malatji, Kgashane Leroy; Beckmann, Kristine Sønstevold; Wiedeking, Mathis; Siem, Sunniva; Goriely, Stephane & Larsen, Ann-Cecilie [Vis alle 21 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Midtbø, Jørgen E.; Zeiser, Fabio; Lima, Erlend; Larsen, Ann-Cecilie; Tveten, Gry Merete & Guttormsen, Magne Sveen [Vis alle 9 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Zeiser, Fabio; Tveten, Gry Merete; Bello Garrote, Frank Leonel; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie & Ingeberg, Vetle Wegner [Vis alle 8 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• 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. Fulltekst i vitenarkiv
• Scholz, P.; Guttormsen, Magne Sveen; Heim, F.; Larsen, Ann-Cecilie; Mayer, J. & Savran, D. [Vis alle 12 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Pérez Sánchez, R.; Jurado, Beatriz; Meot, V; Roig, O; Dupuis, M & Denis-Petit, D [Vis alle 21 forfattere av denne artikkelen] (2020). Simultaneous Determination of Neutron-Induced Fission and Radiative Capture Cross Sections from Decay Probabilities Obtained with a Surrogate Reaction. Physical Review Letters. ISSN 0031-9007. 125. doi: 10.1103/physrevlett.125.122502. Fulltekst i vitenarkiv
• Kibédi, T.; Alshahrani, B.; Stuchbery, A.E.; Larsen, Ann-Cecilie; Görgen, Andreas & Siem, Sunniva [Vis alle 20 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Ingeberg, Vetle Wegner; Siem, Sunniva; Wiedeking, Mathis; Sieja, Kamila; Bleuel, D.l. & Brits, C.P. [Vis alle 29 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Larsen, Ann-Cecilie; Liddick, Sean N.; Spyrou, Artemis; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel & Midtbø, Jørgen E. [Vis alle 7 forfattere av denne artikkelen] (2019). The Beta-Oslo Method: ExperimentallyConstrained (n,γ) Reaction RatesRelevant to ther-Process. I Formicola, Alba; Junker, Matthias; Gialanella, Lucio & Imbriani, Gianluca (Red.), Nuclei in the Cosmos XV. Springer. ISSN 978-3-030-13875-2. s. 137–140. doi: 10.1007/978-3-030-13876-9_22.
• Guttormsen, Magne Sveen; Goriely, Stephane; Larsen, Ann-Cecilie; Görgen, Andreas; Hagen, Trine Wiborg & Renstrøm, Therese [Vis alle 13 forfattere av denne artikkelen] (2019). Indirect(n,γ)91,92Zr Cross SectionMeasurements for the s-Process. I Formicola, Alba; Junker, Matthias; Gialanella, Lucio & Imbriani, Gianluca (Red.), Nuclei in the Cosmos XV. Springer. ISSN 978-3-030-13875-2. s. 359–362. doi: 10.1007/978-3-030-13876-9_65.
• Voinov, Alexander; Renstrøm, Therese; Bleuel, D.l.; Grimes, S.M.; Guttormsen, Magne Sveen & Larsen, Ann-Cecilie [Vis alle 23 forfattere av denne artikkelen] (2019). Level densities of 74,76Ge from compound nuclear reactions. Physical Review C. ISSN 2469-9985. 99(5). doi: 10.1103/PhysRevC.99.054609. Fulltekst i vitenarkiv
• Brits, C.P.; Malatji, Kgashane L.; Wiedeking, M.; Kheswa, BV; Goriely, S. & Bello Garrote, Frank Leonel [Vis alle 27 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Zeiser, Fabio; Tveten, Gry Merete; Potel, Gregory; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen & Laplace, Thibault A. [Vis alle 22 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Lyons, Stephanie; Spyrou, Artemis; Liddick, Sean N.; Naqvi, Farheen; Crider, Benjamin P. & Dombos, Alexander C. [Vis alle 25 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Liddick, Sean N.; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Spyrou, Artemis; Crider, Benjamin P. & Naqvi, Farheen [Vis alle 30 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• 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. Fulltekst i vitenarkiv
• Kullmann, Ina Kristine Berentsen; Larsen, Ann-Cecilie; Renstrøm, Therese; Beckmann, Kristine Sønstevold; Bello Garrote, Frank Leonel & Crespo Campo, Lucia [Vis alle 13 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Naqvi, F.; Simon, Anna; Guttormsen, Magne Sveen; Schwengner, R; Frauendorf, S & Reingold, C. S. [Vis alle 11 forfattere av denne artikkelen] (2019). Nuclear level densities and γ-ray strength functions in samarium isotopes. Physical Review C. ISSN 2469-9985. 99(5). doi: 10.1103/PhysRevC.99.054331. Fulltekst i vitenarkiv
• Malatji, Kgashane Leroy; Wiedeking, Mathis; Goriely, Stephane; Brits, Christiaan Petrus; Kheswa, Bonginkosi Vincent & Bello Garrote, Frank Leonel [Vis alle 22 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Lewis, Rebecca; Liddick, Sean N.; Larsen, Ann-Cecilie; Spyrou, Artemis; Bleuel, Darren L. & Couture, Aaron J. [Vis alle 17 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Midtbø, Jørgen E.; Guttormsen, Magne Sveen; Renstrøm, Therese; Liddick, Sean N. & Spyrou, Artemis [Vis alle 22 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Jones, M.D.; Macchiavelli, Augusto Oswaldo; Wiedeking, Mathis; Bernstein, Lee A.; Crawford, Heather L. & Campbell, C.M. [Vis alle 30 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Crespo Campo, Lucia; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Giacoppo, Francesca & Görgen, Andreas [Vis alle 15 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Renstrøm, Therese; Utsunomiya, H.; Nyhus, Hilde-Therese; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen & Tveten, Gry Merete [Vis alle 16 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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; Goriely, Stéphane; Katayama, Seitaro & Ari-Izumi, Takashi [Vis alle 22 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Midtbø, Jørgen E.; Crespo Campo, Lucia; Görgen, Andreas & Ingeberg, Vetle Wegner [Vis alle 11 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Wiedeking, Mathis; Bernstein, Lee A.; Bleuel, Darren L.; Brits, Christiaan Petrus; Sowazi, Khanyisa & Görgen, Andreas [Vis alle 16 forfattere av denne artikkelen] (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.
• Jurado, B; Marini, P; Mathieu, L; Aiche, M; Czajkowski, S & Tsekhanovich, I [Vis alle 19 forfattere av denne artikkelen] (2017). Investigation of the surrogate-reaction method via the simultaneous measurement of gamma-emission and fission probabilities. The European Physical Journal Conferences. ISSN 2101-6275. 146. doi: 10.1051/epjconf/201714611006.
• Brits, C.P.; Wiedeking, M.; Bello Garrote, Frank Leonel; Bleuel, D. L.; Giacoppo, F. & Görgen, Andreas [Vis alle 22 forfattere av denne artikkelen] (2017). Resonances in odd-odd 182Ta. The European Physical Journal Conferences. ISSN 2101-6275. 146. doi: 10.1051/epjconf/201714605012. Fulltekst i vitenarkiv
• Malatji, Kgashane L.; Kheswa, Bonginkosi Vincent; Wiedeking, M.; Bello Garrote, Frank Leonel; Brits, C.P. & Bleuel, D. L. [Vis alle 21 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Spyrou, Artemis; Liddick, Sean N.; Guttormsen, Magne Sveen; Ingeberg, Vetle Wegner & Siem, Sunniva [Vis alle 25 forfattere av denne artikkelen] (2017). Novel Techniques for Constraining Neutron-capture Rates relevant to Heavy-element Nucleosynthesis. Proceedings of Science (PoS). ISSN 1824-8039. INPC2016. doi: 10.22323/1.281.0360. Fulltekst i vitenarkiv
• Tveten, Gry Merete; Spyrou, Artemis; Schwengner, Ronald; Naqvi, Farheen; Larsen, Ann-Cecilie & Renstrøm, Therese [Vis alle 23 forfattere av denne artikkelen] (2017). The Statistical Properties Of 92Mo And Implications For The p-process. Proceedings of Science (PoS). ISSN 1824-8039. INPC2016. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Crespo Campo, Lucia; Larsen, Ann-Cecilie; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Giacoppo, Francesca & Görgen, Andreas [Vis alle 13 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Rose, Sunniva Johanne; Zeiser, Fabio; Wilson, JN; Oberstedt, A; Oberstedt, S & Siem, Sunniva [Vis alle 25 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Goriely, Stephan; Larsen, Ann-Cecilie; Görgen, Andreas; Hagen, Trine Wiborg & Renstrøm, Therese [Vis alle 13 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Spyrou, Artemis; Larsen, Ann-Cecilie; Liddick, Sean N.; Naqvi, Farheen; Crider, Benjamin P. & Dombos, Alexander C. [Vis alle 19 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Kheswa, Bonginkosi Vincent; Wiedeking, Mathis; Brown, Joshua A.; Larsen, Ann-Cecilie; Goriely, Stéphane & Guttormsen, Magne Sveen [Vis alle 25 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Blasi, Nives; Bracco, Angela; Camera, Franco & Crespo Campo, Lucia [Vis alle 24 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Görgen, Andreas; Renstrøm, Therese; Siem, Sunniva & Tornyi, Tamas Gabor [Vis alle 7 forfattere av denne artikkelen] (2016). Is the generalized Brink-Axel hypothesis valid? Proceedings of Science (PoS). ISSN 1824-8039. 2016-September, s. 1–8. doi: 10.22323/1.281.0062. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Spyrou, Artemisia; Liddick, Sean N.; Guttormsen, Magne Sveen; Ingeberg, Vetle Wegner & Siem, Sunniva [Vis alle 25 forfattere av denne artikkelen] (2016). Novel techniques for constraining neutron-capture rates relevant to heavy-element nucleosynthesis. Proceedings of Science (PoS). ISSN 1824-8039. 2016-September:360, s. 1–9. Fulltekst i vitenarkiv
• Tveten, Gry Merete; Spyrou, Artemis; Schwengner, Ronald; Naqvi, Farheen; Larsen, Ann-Cecilie & Renstrøm, Therese [Vis alle 23 forfattere av denne artikkelen] (2016). The statistical properties of 92Mo and implications for the p-process. Proceedings of Science (PoS). ISSN 1824-8039. 2016-September:163.
• Crespo Campo, Lucia; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Görgen, Andreas; Guttormsen, Magne Sveen & Hadynska-Klek, Katarzyna [Vis alle 14 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Ay, K.o.; Ozgur, Mustafa; Algin, Emel; Guttormsen, Magne Sveen; Bello Garrote, Frank Leonel & Crespo Campo, Lucia [Vis alle 20 forfattere av denne artikkelen] (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.
• Negi, D; Wiedeking, M; Lanza, EG; Litvinova, E; Vitturi, A & Bark, RA [Vis alle 35 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Ducasse, Q; Jurado, B; Aiche, M; Marini, P; Mathieu, L & Görgen, Andreas [Vis alle 29 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Tveten, Gry Merete; Spyrou, A; Schwengner, R; Naqvi, F; Larsen, Ann-Cecilie & Eriksen, Tomas Kvalheim [Vis alle 23 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Marini, P.; Ducasse, Q; Jurado, B; Aiche, M; Mathieu, L & Barreau, G. [Vis alle 33 forfattere av denne artikkelen] (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.
• Spyrou, Artemis; Liddick, Sean N.; Naqvi, Farheen; Crider, Benjamin P.; Dombos, Alexander C. & Bleuel, Darren L. [Vis alle 21 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Liddick, Sean N.; Spyrou, Artemisia; Crider, Benjamin P.; Naqvi, Farheen; Larsen, Ann-Cecilie & Guttormsen, Magne Sveen [Vis alle 21 forfattere av denne artikkelen] (2016). Experimental Neutron Capture Rate Constraint Far from Stability. Physical Review Letters. ISSN 0031-9007. 116:242502(24). doi: 10.1103/PhysRevLett.116.242502. Fulltekst i vitenarkiv
• Renstrøm, Therese; Nyhus, Hilde-Therese; Utsunomiya, Hiroaki; Schwengner, Ronald; Goriely, Stephane & Larsen, Ann-Cecilie [Vis alle 25 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Schwengner, Ronald; Bleuel, Darren L.; Goriely, Stephane & Harrisopulos, Sotirios [Vis alle 21 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Simon, Anna; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Beausang, Con W.; Humby, Peter & Burke, Jason T. [Vis alle 17 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Laplace, Thibault A.; Zeiser, Fabio; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Bleuel, Darren L. & Bernstein, Lee A. [Vis alle 27 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Görgen, Andreas; Renstrøm, Therese; Siem, Sunniva & Tornyi, Tamas Gabor [Vis alle 7 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Moretto, Luciano; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen & Siem, Sunniva (2015). The little hagedorn that could. Proceedings of Science (PoS). ISSN 1824-8039. 26-30-January-2015:058. Fulltekst i vitenarkiv
• Renstrøm, Therese; Nyhus, Hilde-Therese; Utsunomiya, Hiroaki; Larsen, Ann-Cecilie; Siem, Sunniva & Guttormsen, Magne Sveen [Vis alle 25 forfattere av denne artikkelen] (2015). First evidence of low energy enhancement in Ge isotopes. The European Physical Journal Conferences. ISSN 2101-6275. 93. doi: 10.1051/epjconf/20159304003. Fulltekst i vitenarkiv
• Kheswa, Bonginkosi Vincent; Wiedeking, Mathis; Giacoppo, Francesca; Goriely, Stephane; Guttormsen, Magne Sveen & Larsen, Ann-Cecilie [Vis alle 19 forfattere av denne artikkelen] (2015). Statistical nuclear properties and synthesis of La-138. The European Physical Journal Conferences. ISSN 2101-6275. 93. doi: 10.1051/epjconf/20159304005.
• Giacoppo, Francesca; Bello Garrote, Frank Leonel; Eriksen, Tomas Kvalheim; Görgen, Andreas; Guttormsen, Magne Sveen & Hagen, Trine Wiborg [Vis alle 16 forfattere av denne artikkelen] (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. [Vis alle 27 forfattere av denne artikkelen] (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.
• Tveten, Gry Merete; Bello Garrote, Frank Leonel; Crespo Campo, Lucia; Eriksen, Tomas Kvalheim; Giacoppo, Francesca & Guttormsen, Magne Sveen [Vis alle 18 forfattere av denne artikkelen] (2015). The statistical properties of 111,112,113Sn studied with the Oslo method. The European Physical Journal Conferences. ISSN 2101-6275. 93. doi: 10.1051/epjconf/20159304004. Fulltekst i vitenarkiv
• Giacoppo, Francesca; Bello Garrote, Frank Leonel; Bernstein, Lee; Bleuel, D.l.; Firestone, R.B. & Görgen, Andreas [Vis alle 16 forfattere av denne artikkelen] (2015). Gamma decay from the quasicontinuum of 197,198Au. Physical Review C. Nuclear Physics. ISSN 0556-2813. 91. doi: 10.1103/PhysRevC.91.054327. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Goriely, Stephane; Bernstein, L. A.; Bleuel, D. L.; Bracco, A. & Brown, B. A. [Vis alle 25 forfattere av denne artikkelen] (2015). Upbend and M1 scissors mode in neutron-rich nuclei — consequences for r-process (n,gamma) reaction rates . Acta Physica Polonica B. ISSN 0587-4254. 46(3), s. 509–512. doi: 10.5506/APhysPolB.46.509. Fulltekst i vitenarkiv
• Kheswa, Bonginkosi Vincent; Wiedeking, Mathis; Giacoppo, Francesca; Goriely, Stephan; Guttormsen, Magne Sveen & Larsen, Ann-Cecilie [Vis alle 19 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Moretto, L.G.; Larsen, Ann-Cecilie; Giacoppo, Francesca; Guttormsen, Magne Sveen & Siem, Sunniva (2015). Experimental first order pairing phase transition in atomic nuclei. Journal of Physics: Conference Series (JPCS). ISSN 1742-6588. 580:012048, s. 1–7. doi: 10.1088/1742-6596/580/1/012048. Fulltekst i vitenarkiv
• Giacoppo, Francesca; Bello Garrote, Frank Leonel; Bernstein, Lee A.; Bleuel, Darren L.; Firestone, Richard & Görgen, Andreas [Vis alle 16 forfattere av denne artikkelen] (2014). Statistical gamma-ray emission of gold and its astrophysical implications. The European Physical Journal Conferences. ISSN 2101-6275. 66:02041. doi: 10.1051/epjconf/20146602041.
• Guttormsen, Magne Sveen; Bernstein, L. A.; Bürger, Alexander; Görgen, Andreas; Gunsing, F. & Hagen, Trine Wiborg [Vis alle 11 forfattere av denne artikkelen] (2014). Scissors strength in the quasi-continuum of actinides. The European Physical Journal Conferences. ISSN 2101-6275. 66. doi: 10.1051/epjconf/20146602044.
• Larsen, Ann-Cecilie; Blasi, Nives; Bracco, Angela; Bürger, Arnold; Camera, Franco & Eriksen, Tomas Kvalheim [Vis alle 24 forfattere av denne artikkelen] (2014). Low-energy enhancement of nuclear γ strength and its impact on astrophysical reaction rates. The European Physical Journal Conferences. ISSN 2101-6275. 66:07014. doi: 10.1051/epjconf/20146607014. Fulltekst i vitenarkiv
• Bree, Nick; Wrzosek-Lipska, K; Petts, A; Andreyev, A; Bastin, B & Bender, M [Vis alle 70 forfattere av denne artikkelen] (2014). Shape coexistence in the neutron-deficient even-even hg 182-188 isotopes studied via coulomb excitation. Physical Review Letters. ISSN 0031-9007. 112:162701(16). doi: 10.1103/PhysRevLett.112.162701.
• Spyrou, A.; Liddick, S.N.; Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Cooper, K. & Dombos, A.C. [Vis alle 15 forfattere av denne artikkelen] (2014). Novel technique for Constraining r-Process (n, γ) Reaction Rates. Physical Review Letters. ISSN 0031-9007. 113(232502). doi: 10.1103/PhysRevLett.113.232502. Fulltekst i vitenarkiv
• Giacoppo, Francesca; Bello Garrote, Frank Leonel; Bernstein, L. A.; Bleuel, D. L.; Eriksen, Tomas Kvalheim & Firestone, Richard [Vis alle 18 forfattere av denne artikkelen] (2014). Level densities and thermodynamical properties of Pt and Au isotopes. Physical Review C. Nuclear Physics. ISSN 0556-2813. 90(5). doi: 10.1103/PhysRevC.90.054330. Fulltekst i vitenarkiv
• Voinov, A.V.; Grimes, S.M.; Brune, C.R.; Bürger, Alexander; Görgen, Andreas & Guttormsen, Magne Sveen [Vis alle 9 forfattere av denne artikkelen] (2014). Level Density Inputs in Nuclear Reaction Codes and the Role of the Spin Cutoff Parameter. Nuclear Data Sheets. ISSN 0090-3752. 119. doi: 10.1016/j.nds.2014.08.070.
• Ducasse, Quentin; Jurado, Beatriz; Tornyi, Tamas Gabor; Görgen, Andreas; Wilson, J.D. & Giacoppo, Francesca [Vis alle 28 forfattere av denne artikkelen] (2014). Neutron-induced Cross Sections of Actinides via the Surrogate-reaction Method. Nuclear Data Sheets. ISSN 0090-3752. 119. doi: 10.1016/j.nds.2014.08.064.
• Eriksen, Tomas Kvalheim; Nyhus, Hilde-Therese; Guttormsen, Magne Sveen; Görgen, Andreas; Larsen, Ann-Cecilie & Renstrøm, Therese [Vis alle 11 forfattere av denne artikkelen] (2014). Pygmy resonance and low-energy enhancement in the γ-ray strength functions of Pd isotopes. Physical Review C. Nuclear Physics. ISSN 0556-2813. 90(044311). doi: 10.1103/PhysRevC.90.044311.

Se alle arbeider i Cristin

• Guttormsen, Magne Sveen (2019). Mini-workshop on the beta-Oslo method.
• Guttormsen, Magne Sveen (2019). Level density in Nd isotopes as function of deformation.
• Guttormsen, Magne Sveen (2019). Nøytronets mørke side.
• Guttormsen, Magne Sveen (2018). The beta-Oslo method.
• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Midtbø, Jørgen E.; Crespo Campo, Lucia; Görgen, Andreas & Ingeberg, Vetle Wegner [Vis alle 11 forfattere av denne artikkelen] (2017). Gamma-widths, lifetimes and fluctuations in the nuclear quasi-continuum.
• Guttormsen, Magne Sveen (2017). Gamma-widths, lifetimes and fluctuations in the nuclear quasi-continuum .
• Guttormsen, Magne Sveen (2017). On the validity of the generalized Brink-Axel hypothesis.
• Guttormsen, Magne Sveen (2017). The beta-Oslo method.
• Tveten, Gry Merete; Spyrou, Artemis; Schwengner, Ronald; Naqvi, Farheen; Larsen, Ann-Cecilie & Eriksen, Tomas Kvalheim [Vis alle 23 forfattere av denne artikkelen] (2016). The Statistical Properties Of 92Mo And Implications For The p-process. Vis sammendrag

  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.

• Guttormsen, Magne Sveen (2016). On the validity of the generalised Brink-Axel hypothesis.
• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Görgen, Andreas; Renstrøm, Therese; Siem, Sunniva & Tornyi, Tamas Gabor [Vis alle 7 forfattere av denne artikkelen] (2016). Is the generalized Brink-Axel hypothesis valid?
• Guttormsen, Magne Sveen (2016). On the validity of the Brink-Axel hypothesis.
• Guttormsen, Magne Sveen (2016). Nuclear structure in the quasi-continuum.
• Guttormsen, Magne Sveen (2015). Thermodynamic and electromagnetic properties of nuclei.
• Guttormsen, Magne Sveen (2015). Adam's Early Era at HMI, Berlin.
• Guttormsen, Magne Sveen (2015). Scissors resonances in the quasi-continuum of heavy nuclei.
• Guttormsen, Magne Sveen (2015). The standard Oslo method.
• Guttormsen, Magne Sveen (2015). My projects in CAN.
• Guttormsen, Magne Sveen (2014). Level density of atomic nuclei.

Se alle arbeider i Cristin