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• Magagula, S.P.E.; Malatji, Kgashane Leroy; Wiedeking, M.; Pellegri, L; Beckmann, Kristine Sønstevold & Garrote, Frank Leonel Bello [Vis alle 18 forfattere av denne artikkelen] (2023). Investigating the strength of the scissors mode in 151Sm. Journal of Physics: Conference Series (JPCS). ISSN 1742-6588. doi: 10.1088/1742-6596/2586/1/012070. Fulltekst i vitenarkiv Vis sammendrag

  Change in nuclei deformation leads to changes in statistical properties such as the nuclear level density (NLD) and γ-ray strength function (γSF). The NLD and γSF of 151Sm were extracted using the Oslo method. The strength of the scissors resonance (SR) and its centroid energy for 151Sm were found to be 2.13 ± 0.60 µ2N and 2.48 ± 0.25 MeV, respectively. These results were used to place the SR of 151Sm and its magnetic dipole strength B(M1)SR into the context of previously measured Sm isotopes.

• Garrote, Frank Leonel Bello; Lopez-Martens, Araceli; Larsen, Ann-Cecilie; Deloncle, I.; Péru, Sophie & Zeiser, Fabio [Vis alle 39 forfattere av denne artikkelen] (2022). Experimental observation of the M1 scissors mode in ²⁵⁴No. Physics Letters B. ISSN 0370-2693. 834. doi: 10.1016/j.physletb.2022.137479. Fulltekst i vitenarkiv Vis sammendrag

  We present the first experimental evidence of the scissors mode in the superheavy nucleus 254No produced in the 208Pb(48Ca, 2nγ))254No reaction. The spectrum of γrays emitted by the excited 254No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5MeV. By measuring the linear polarization properties of the emitted γrays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of 254No were performed. The observed enhancement is reproduced by including an M1component in the γstrength function with total strength B(M1↑)=11.8(19)μ2N. This is in good agreement with the integrated M1strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei.

• Guttormsen, Magne Sveen; Ay, Kursad Osman; Ozgur, Mustafa; Algin, Emel; Larsen, Ann-Cecilie & Garrote, Frank Leonel Bello [Vis alle 26 forfattere av denne artikkelen] (2022). Evolution of the γ -ray strength function in neodymium isotopes. Physical Review C. ISSN 2469-9985. 106(3). doi: 10.1103/PhysRevC.106.034314. Fulltekst i vitenarkiv Vis sammendrag

  The experimental γ-ray strength functions (γSFs) of 142,144–151Nd have been studied for γ-ray energies up to the neutron separation energy using the Oslo method. The results represent a unique set of γSFs for an isotopic chain with increasing nuclear deformation. The data reveal how the low-energy enhancement, the scissors mode, and the pygmy dipole resonance evolve with nuclear deformation and mass number. This indicates that the mechanisms behind the low-energy enhancement and the scissors mode are decoupled from each other.

• 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 Vis sammendrag

  Understanding the evolution of level densities in the crossover from spherical to well-deformed nuclei has been a long-standing problem in nuclear physics. We measure nuclear level densities for a chain of neodymium isotopes 142,144−151Nd which exhibit such a crossover. These results represent the most complete data set of nuclear level densities to date for an isotopic chain between neutron shell-closure and towards mid-shell. We observe a strong increase of the level densities along the chain with an overall increase by a factor of ≈150 at an excitation energy of 6 MeV and saturation around mass 150. Level densities calculated by the shell model Monte Carlo (SMMC) are in excellent agreement with these experimental results. Based on our experimental and theoretical findings, we offer an explanation of the observed mass dependence of the level densities in terms of the intrinsic single-particle level density and the collective enhancement.

• Brits, C.P.; Malatji, Kgashane L.; Wiedeking, M.; Kheswa, BV; Goriely, S. & Garrote, Frank Leonel Bello [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 Vis sammendrag

  Particle- γ coincidence experiments were performed at the Oslo Cyclotron Laboratory with the 181 Ta ( d , X ) and 181 Ta ( 3 He , X ) reactions to measure the nuclear level densities (NLDs) and γ -ray strength functions ( γ SFs ) of 180 , 181 , 182 Ta using the Oslo method. The back-shifted Fermi-gas, constant temperature plus Fermi gas, and Hartree-Fock-Bogoliubov plus combinatorial models were used for the absolute normalizations of the experimental NLDs at the neutron separation energies. The NLDs and γ SFs are used to calculate the corresponding 181 Ta ( n , γ ) cross sections and these are compared to results from other techniques. The energy region of the scissors resonance strength is investigated and from the data and comparison to prior work it is concluded that the scissors strength splits into two distinct parts. This splitting may allow for the determination of triaxiality and a γ deformation of 14 . 9 ∘ ± 1 . 8 ∘ was determined for 181 Ta .

• 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 Vis sammendrag

  Numerous scientific fields including astrophysics, nuclear power, and nuclear forensics require a knowledge of basic nuclear properties for large numbers of short-lived, radioactive isotopes far removed from stable nuclei. Neutron-capture cross sections are one such piece of nuclear data where direct measurements are not possible and theoretical predictions can vary by orders of magnitude. A recently developed indirect technique for inferring neutron capture rates, the β -Oslo method, has been introduced but not compared against a known, directly measured neutron capture cross section. To provide this benchmark, two indirect methods based on β decay and charged-particle reactions were used to extract the nuclear level density and γ -ray strength function of 51 Ti . The nuclear level density and γ -ray strength function from the two data sets were found to be equivalent and were used to extract the neutron capture cross section of 50 Ti which agrees with previous direct measurements at high neutron energies. The results demonstrate the validity of the β -Oslo method for extracting neutron capture cross sections of short-lived nuclei and provide a sufficiently small uncertainty to be used in various applications.

• 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 9783030138752. s. 359–362. doi: 10.1007/978-3-030-13876-9_65. Fulltekst i vitenarkiv
• Malatji, Kgashane Leroy; Wiedeking, Mathis; Goriely, Stephane; Brits, Christiaan Petrus; Kheswa, Bonginkosi Vincent & Garrote, Frank Leonel Bello [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
• Hagen, Trine Wiborg; Görgen, Andreas; Korten, Wolfram; Grente, Lucie; Salsac, Marie Delphine & Farget, F. [Vis alle 28 forfattere av denne artikkelen] (2018). Lifetimes of excited states in triaxially deformed 107Tc and 109,111,113Rh. European Physical Journal A. ISSN 1434-6001. 54, s. 1–11. doi: 10.1140/epja/i2018-12482-9. Fulltekst i vitenarkiv
• Singh, Purnima; Korten, Wolfram; Hagen, Trine Wiborg; Görgen, Andreas; Grente, Lucie & Salsac, Marie Delphine [Vis alle 38 forfattere av denne artikkelen] (2018). Evidence for coexisting shapes through lifetime measurements in 98Zr. Physical Review Letters. ISSN 0031-9007. 121(19). doi: 10.1103/PhysRevLett.121.192501. Fulltekst i vitenarkiv Vis sammendrag

  The lifetimes of the first excited 2þ, 4þ, and 6þ states in 98Zr were measured with the recoil-distance Doppler shift method in an experiment performed at GANIL. Excited states in 98Zr were populated using the fission reaction between a 6.2 MeV=u 238U beam and a 9 Be target. The γ rays were detected with the EXOGAM array in correlation with the fission fragments identified by mass and atomic number in the VAMOS++ spectrometer. Our result shows a very small BðE2; 2þ 1 → 0þ 1 Þ value in 98Zr, thereby confirming the very sudden onset of collectivity at N ¼ 60. The experimental results are compared to large-scale Monte Carlo shell model and beyond-mean-field calculations. The present results indicate the coexistence of two additional deformed shapes in this nucleus along with the spherical ground state.

• Brits, C.P.; Wiedeking, M.; Garrote, Frank Leonel Bello; 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 Vis sammendrag

  Enhanced γ -decay on the tail of the giant electric dipole resonance, such as the scissors or pygmy resonances, can have significant impact on (n,γ ) reaction rates. These rates are important input for modeling processes that take place in astrophysical environments and nuclear reactors. Recent results from the University of Oslo indicate the existence of a significant enhancement in the photon strength function for nuclei in the actinide region due to the scissors resonance. Further, the M1 strength distribution of the scissors resonances in rare earth nuclei has been studied extensively over the years. To investigate the evolution and persistence of the scissor resonance in other mass regions, an experiment was performed utilizing the NaI(Tl) γ -ray detector array (CACTUS) and silicon particle telescopes (SiRi) at the University of Oslo Cyclotron laboratory. Particle-γ coincidences from the 181Ta(d,p)182Ta and 181Ta(d,d’)181Ta reactions were used to measure the nuclear level density and photon strength function of the well-deformed 181Ta and 182Ta systems, to investigate the existence of resonances below the neutron separation energy.

• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Blasi, Nives; Bracco, Angela; Camera, Franco & Campo, Lucia Crespo [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 Vis sammendrag

  Nuclear level densities and γ-ray strength functions of 56,57Fe have been extracted from proton-γ coincidences. A low-energy enhancement in the γ-ray strength functions up to a factor of 30 over common theoretical E1 models is confirmed. Angular distributions of the low-energy enhancement in 57Fe indicate its dipole nature, in agreement with findings for 56Fe. The high statistics and the excellent energy resolution of the large-volume LaBr3(Ce) detectors allowed for a thorough analysis of γ strength as function of excitation energy. Taking into account the presence of strong Porter–Thomas fluctuations, there is no indication of any significant excitation energy dependence in the γ-ray strength function, in support of the generalized Brink–Axel hypothesis. This research was first published in Journal of Physics G: Nuclear and Particle Physics. © IOP Publishing.

• Hagen, Trine Wiborg; Görgen, Andreas; Korten, W.; Grente, L; Salsac, MD & Farget, F [Vis alle 29 forfattere av denne artikkelen] (2017). Evolution of nuclear shapes in odd-mass yttrium and niobium isotopes from lifetime measurements following fission reactions. Physical Review C. ISSN 2469-9985. 95(3). doi: 10.1103/PhysRevC.95.034302. Fulltekst i vitenarkiv
• Malatji, Kgashane L.; Kheswa, Bonginkosi Vincent; Wiedeking, M.; Garrote, Frank Leonel Bello; 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 Vis sammendrag

  The γ -ray strength functions and nuclear level densities in the quasi-continuum of 180,181Ta are extracted from particle-γ coincidence events with the Oslo Method, below the Sn . The data were used as input in the TALYS reaction code for calculations of the astrophysical Maxwellian-averaged (n, γ ) cross-sections to investigate nucleosynthesis of nature’s rarest stable isotope 180Ta.

• 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 Vis sammendrag

  Nuclear level densities (NLDs) and γ-ray strength functions (γSFs) have been extracted from particle-γ coincidences of the 92Zr(p,p′γ)92Zr and 92Zr(p,dγ)91Zr reactions using the Oslo method. The new 91,92ZrγSF data, combined with photonuclear cross sections, cover the whole energy range from Eγ≈1.5MeV up to the giant dipole resonance at Eγ≈17 MeV. The wide-range γSF data display structures at Eγ≈9.5 MeV, compatible with a superposition of the spin-flip M1 resonance and a pygmy E1 resonance. Furthermore, the γSF shows a minimum at Eγ≈2–3MeV and an increase at lower γ-ray energies. The experimentally constrained NLDs and γSFs are shown to reproduce known (n,γ) and Maxwellian-averaged cross sections for 91,92Zr using the talys reaction code, thus serving as a benchmark for this indirect method of estimating (n,γ) cross sections for Zr isotopes. This research was originally published in Physical Review C - Nuclear Physics. © American Physical Society

• 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 Vis sammendrag

  Prompt-fission γ rays are responsible for approximately 5% of the total energy released in fission, and therefore important to understand when modeling nuclear reactors. In this work we present prompt γ -ray emission characteristics in fission as a function of the nuclear excitation energy of the fissioning system. Emitted γ -ray spectra were measured, and γ -ray multiplicities and average and total γ energies per fission were determined for the 233 U ( d , p f ) reaction for excitation energies between 4.8 and 10 MeV, and for the 239 Pu ( d , p f ) reaction between 4.5 and 9 MeV. The spectral characteristics show no significant change as a function of excitation energy above the fission barrier, despite the fact that an extra ∼ 5 MeV of energy is potentially available in the excited fragments for γ decay. The measured results are compared with model calculations made for prompt γ -ray emission with the fission model code gef. Further comparison with previously obtained results from thermal neutron induced fission is made to characterize possible differences arising from using the surrogate ( d , p ) reaction.

• 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). 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.

• 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 Vis sammendrag

  The nuclear level densities and γ-ray strength functions of 138,139,140La were measured using the 139La(3He,α), 139La(3He,'3He), and 139La(d,p) reactions. The particle-γ coincidences were recorded with the silicon particle telescope (SiRi) and NaI(Tl) (CACTUS) arrays. In the context of these experimental results, the low-energy enhancement in the A∼140 region is discussed. The 137,138,139La(n,γ) cross sections were calculated at s- and p-process temperatures using the experimentally measured nuclear level densities and γ-ray strength functions. Good agreement is found between 139La(n,γ) calculated cross sections and previous measurements. This research was first published in Physical Review C - Nuclear Physics. © American Physical Society.

• Ay, K.o.; Ozgur, Mustafa; Algin, Emel; Guttormsen, Magne Sveen; Garrote, Frank Leonel Bello & Campo, Lucia Crespo [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. 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 Vis sammendrag

  The γ -ray strength functions and level densities of 73,74Ge have been extracted up to the neutron-separation energy Sn from particle-γ coincidence data using the Oslo method. Moreover, the γ -ray strength function of 74Ge above Sn has been determined from photoneutron measurements; hence these two experiments cover the range of Eγ ≈ 1–13 MeV for 74Ge. The obtained data show that both 73,74Ge display an increase in strength at low γ energies. The experimental γ -ray strength functions are compared with M1 strength functions deduced from average B(M1) values calculated within the shell model for a large number of transitions. The observed low-energy enhancements in 73,74Ge are adopted in the calculations of the 72,73Ge(n,γ ) cross sections, where there are no direct experimental data. Calculated reaction rates for more neutron-rich germanium isotopes are shown to be strongly dependent on the presence of the low-energy enhancement.

• 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 Vis sammendrag

  The nuclear level density and the γ -ray strength function have been extracted for 89Y by using the Oslo method on 89Y(p,p γ ) 89Y coincidence data. The γ -ray strength function displays a low-energy enhancement consistent with previous observations in this mass region (93–98Mo). Shell-model calculations support the conclusion that the observed enhancement is due to strong, low-energy M1 transitions at high excitation energies. The data were further used as input for calculations of the 88Sr(p,γ ) 89Y and 88Y(n,γ ) 89Y cross sections with the TALYS reaction code. Comparison with cross-section data, where available, as well as with values from the BRUSLIB library, shows a satisfying agreement.

• 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 Vis sammendrag

  We investigated the 238U(d,p) reaction as a surrogate for the n + 238U reaction. For this purpose we measured for the first time the γ -decay and fission probabilities of 239U∗ simultaneously and compared them to the corresponding neutron-induced data. We present the details of the procedure to infer the decay probabilities, as well as a thorough uncertainty analysis, including parameter correlations. Calculations based on the continuumdiscretized coupled-channels method and the distorted-wave Born approximation (DWBA) were used to correct our data from detected protons originating from elastic and inelastic deuteron breakup. In the region where fission and γ emission compete, the corrected fission probability is in agreement with neutron-induced data, whereas the γ -decay probability is much higher than the neutron-induced data. We have performed calculations of the decay probabilities with the statistical model and of the average angular momentum populated in the 238U(d,p) reaction with the DWBA to interpret these results.

• Hagen, Trine Wiborg; Grente, L; Görgen, Andreas; Salsac, MD; Korten, W & Farget, F [Vis alle 30 forfattere av denne artikkelen] (2016). Lifetime measurments of excited states in neutron-rich fission fragments. Acta Physica Polonica B. ISSN 0587-4254. 47(3), s. 903–910. doi: 10.5506/APhysPolB.47.903. 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 Vis sammendrag

  One of the greatest questions for modern physics to address is how elements heavier than iron are created in extreme astrophysical environments. A particularly challenging part of that question is the creation of the so-called p-nuclei, which are believed to be mainly produced in some types of supernovae. The lack of needed nuclear data presents an obstacle in nailing down the precise site and astrophysical conditions. In this work, we present for the first time measurements on the nuclear level density and average γ strength function of 92Mo. State-of-the-art p-process calculations systematically underestimate the observed solar abundance of this isotope. Our data provide stringent constraints on the 91Nb(p,γ ) 92Mo reaction rate, which is the last unmeasured reaction in the nucleosynthesis puzzle of 92Mo. Based on our results, we conclude that the 92Mo abundance anomaly is not due to the nuclear physics input to astrophysical model calculations.

• 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). 2016-September:163. Fulltekst i vitenarkiv
• Giacoppo, Francesca; Garrote, Frank Leonel Bello; 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 Vis sammendrag

  The average electromagnetic dipole response of levels in the quasicontinuum of 197,198Au has been measured using (3He,3He ) and (d,p) reactions. The extracted γ -ray strength functions have been normalized according to three model assumptions for the nuclear spin distribution. An enhancement in the energy region Eγ = 3.0–6.5 MeV is observed for both isotopes. The E1 component of such excess of strength is studied in detail for 198Au and is interpreted as the pygmy dipole resonance with an energy centroid of 5.9(1) MeV and exhausts about 1% of the total integrated strength. The pygmy dipole resonance is shown to have a significant impact on the calculated 197Au(n,γ ) 198Au cross section.

• Tveten, Gry Merete; Garrote, Frank Leonel Bello; Campo, Lucia Crespo; 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 Vis sammendrag

  The γ-ray strength function and level density of 111, 112, 113Sn are being studied at the Oslo Cyclotron Laboratory (OCL) up to the neutron binding energy by applying the Oslo method to particle-γ coincidence data. The preliminary results for the γ-ray strength function are discussed in the context of the results for the more neutron-rich Sn-isotopes previously studied at OCL.

• Guttormsen, Magne Sveen; Aiche, M; Garrote, Frank Leonel Bello; 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. 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 Vis sammendrag

  The γ-ray strength functions and nuclear level densities of 138La and 139La have been measured below the neutron separation energies. These new data were used to calculate astrophysical Maxwellian-averaged () cross-sections to investigate the production and destruction of the p-nucleus 138La in the photodisintegration process. The results confirm the underproduction of 138La in the p-process with respect to the observed abundances and strongly support the ν-process through capture on 138Ba as the main contributor to the synthesis of 138La in Type II supernovae.

• Sahin, Eda; Doncel, M; Sieja, K; Angelis, G De; Gadea, A & Quintana, B [Vis alle 74 forfattere av denne artikkelen] (2015). Shell evolution beyond N=40: 69,71,73Cu. Physical Review C. Nuclear Physics. ISSN 0556-2813. 91(3). doi: 10.1103/PhysRevC.91.034302. Fulltekst i vitenarkiv
• Garrote, Frank Leonel Bello; Görgen, Andreas; Mierzejewski, Jan; Mihai, Corina Mihaela; Delaroche, Jean Paul & Girod, Michel [Vis alle 24 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  Background: The chain of Sm isotopes exhibits a wide range of nuclear shapes and collective behavior. While the onset of deformation for N > 82 has been well studied both experimentally and theoretically, fundamental data is lacking for some Sm isotopes with N < 82. Purpose: Electromagnetic transition rates represent a sensitive test of theoretical nuclear structure models. Lifetime measurements are furthermore complementary to Coulomb excitation experiments, and the two methods together can give access to spectroscopic quadrupole moments. Method: The lifetime of the 2+ 1 state in 140Sm was measured with the recoil-distance Doppler shift technique using the reaction 124Te( 20Ne, 4n) 140Sm at 82 MeV. Theoretical calculations were performed based on a mapped collective Hamiltonian in five quadrupole coordinates (5DCH) and the Gogny D1S interaction. Results: The lifetime of the 2+ 1 state in 140Sm was found to be 9.1(6) ps, corresponding to aB(E2; 2+ 1 → 0+ 1 ) value of 51(4) Weisskopf units. The theoretical calculations are in very good agreement with the experimental result. Conclusions: The B(E2; 2+ 1 → 0+ 1 ) value for 140Sm fits smoothly into the systematic trend for the chain of Sm isotopes. The new beyond-mean field calculations are able to correctly describe the onset of collectivity in the Sm isotopes below the N = 82 shell closure for the first time.

• Celikovic, I; Dijon, A; Clement, E; France, G De; Isacker, P Van & Ljungvall, J [Vis alle 23 forfattere av denne artikkelen] (2015). Probing collectivity in Zn isotopes with one particle or hole outside the N=40 subshell closure. Physical Review C. Nuclear Physics. ISSN 0556-2813. 91(4). doi: 10.1103/PhysRevC.91.044311. 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 Vis sammendrag

  The γ-strength functions and level densities of 73,74Ge have been extracted from particle-γ coincidence data using the Oslo method. In addition the γ-strength function of 74Ge above the neutron separation threshold, Sn = 10.196 MeV has been extracted from photoneutron measurements. When combined, these two experiments give a γ-strength function covering the energy range of ∼1-13 MeV for 74Ge. This thorough investigation of 74Ge is a part of an international campaign to study the previously reported low energy enhancement in this mass region in the γ-strength function from ∼3 MeV towards lower γ energies. The obtained data show that both 73,74Ge display an increase in strength at low γ energies.

• 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. Fulltekst i vitenarkiv
• Giacoppo, Francesca; Garrote, Frank Leonel Bello; 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. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Bernstein, Lee; Görgen, Andreas; Jurado, Beatriz; Siem, Sunniva & Aiche, M [Vis alle 19 forfattere av denne artikkelen] (2014). Scissors resonance in the quasicontinuum of Th, Pa, and U isotopes. Physical Review C. Nuclear Physics. ISSN 0556-2813. 89(014302). doi: 10.1103/PhysRevC.89.014302. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Garrote, Frank Leonel Bello; Eriksen, Tomas Kvalheim; Giacoppo, Francesca & Görgen, Andreas [Vis alle 16 forfattere av denne artikkelen] (2014). Shell-gap-reduced level densities in 89,90Y. Physical Review C. Nuclear Physics. ISSN 0556-2813. 90(044309). doi: 10.1103/PhysRevC.90.044309. Fulltekst i vitenarkiv
• Giacoppo, Francesca; Garrote, Frank Leonel Bello; 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. Fulltekst i vitenarkiv
• Giacoppo, Francesca; Garrote, Frank Leonel Bello; 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 Vis sammendrag

  The nuclear level densities of 194–196Pt and 197,198Au below the neutron separation energy have been measured using transfer and scattering reactions. All the level density distributions follow the constant-temperature description. Each group of isotopes is characterized by the same temperature above the energy threshold corresponding to the breaking of the first Cooper pair. A constant entropy excess ΔS=1.9kB and 1.1kB is observed in 195Pt and 198Au with respect to 196Pt and 197Au, respectively, giving information on the available single-particle level space for the last unpaired valence neutron. The breaking of nucleon Cooper pairs is revealed by sequential peaks in the microcanonical caloric curve. © 2014 American Physical Society

• Tornyi, Tamas Gabor; Guttormsen, Magne Sveen; Eriksen, Tomas Kvalheim; Görgen, Andreas; Giacoppo, Francesca & Hagen, Trine Wiborg [Vis alle 12 forfattere av denne artikkelen] (2014). Level density and gamma-ray strength function in the odd-odd 238Np nucleus. Physical Review C. Nuclear Physics. ISSN 0556-2813. 89(4). doi: 10.1103/PhysRevC.89.044323. Fulltekst i vitenarkiv
• 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. Fulltekst i vitenarkiv
• 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, s. 233–233. doi: 10.1016/j.nds.2014.08.064. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Blasi, Nives; Bracco, Angela; Bürger, Arnold; Camera, Franco & Eriksen, Tomas Kvalheim [Vis alle 25 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. doi: 10.1051/epjconf/20146607014. Fulltekst i vitenarkiv Vis sammendrag

  An unexpected enhancement in the low-energy part of the γ-strength function for light and medium-mass nuclei has been discovered at the Oslo Cyclotron Laboratory. This enhancement could lead to an increase in the neutron-capture rates up to two orders of magnitude for very exotic, neutron-rich nuclei. However, it is still an open question whether this structure persists when approaching the neutron drip line.

• Larsen, Ann-Cecilie; Blasi, Nives; Bracco, Angela; Camera, Franco; Eriksen, Tomas Kvalheim & Görgen, Andreas [Vis alle 19 forfattere av denne artikkelen] (2013). Evidence for the dipole nature of the low-energy γ enhancement in 56Fe. Physical Review Letters. ISSN 0031-9007. 111(24). doi: 10.1103/PhysRevLett.111.242504. Fulltekst i vitenarkiv Vis sammendrag

  The γ-ray strength function of 56Fe has been measured from proton-γ coincidences for excitation energies up to ≈11  MeV. The low-energy enhancement in the γ-ray strength function, which was first discovered in the (3He,αγ)56Fe reaction, is confirmed with the (p,p′γ)56Fe experiment reported here. Angular distributions of the γ rays give for the first time evidence that the enhancement is dominated by dipole transitions. © 2013 American Physical Society

• Celikovic, I; Dijon, A.; Clement, E; France, G de; Isacker, Pieter Van & Ljungvall, J [Vis alle 22 forfattere av denne artikkelen] (2013). LIFETIME MEASUREMENTS OF Zn ISOTOPES AROUND N=40. Acta Physica Polonica B. ISSN 0587-4254. 44(3), s. 375–380. doi: 10.5506/APhysPolB.44.375. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Jurado, Beatriz; Wilson, J. N.; Aiche, M; Bernstein, L. A. & Ducasse, Quentin [Vis alle 19 forfattere av denne artikkelen] (2013). Constant-temperature level densities in the quasicontinuum of Th and U isotopes. Physical Review C. Nuclear Physics. ISSN 0556-2813. 88(2). doi: 10.1103/PhysRevC.88.024307. Fulltekst i vitenarkiv Vis sammendrag

  Particle-γ coincidences have been measured to obtain γ-ray spectra as a function of excitation energy for 231–233Th and 237–239U. The level densities, which were extracted using the Oslo method, show a constant temperature behavior. The isotopes display very similar temperatures in the quasicontinuum, however, the even-odd isotopes reveal a constant entropy increase ΔS compared to their even-even neighbors. The entropy excess depends on available orbitals for the last unpaired valence neutron of the heated nuclear system. Also, experimental microcanonical temperature and heat capacity have been extracted. Several poles in the heat capacity curve support the idea that an almost continuous melting of Cooper pairs is responsible for the constant-temperature behavior. © 2013 American Physical Society

• Larsen, Ann-Cecilie; Bürger, Alexander; Goriely, Stephane; Guttormsen, Magne Sveen; Görgen, Andreas & Eriksen, Tomas Kvalheim [Vis alle 16 forfattere av denne artikkelen] (2013). Astrophysical reaction rates and the low-energy enhancement in the γ strength. Acta Physica Polonica B. ISSN 0587-4254. 44(3), s. 563–566. doi: 10.5506/APhysPolB.44.563. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Bürger, Alexander; Goriely, Stephane; Guttormsen, Magne Sveen; Görgen, Andreas & Hagen, Trine Wiborg [Vis alle 15 forfattere av denne artikkelen] (2013). Transitional γ strength in Cd isotopes. Physical Review C. Nuclear Physics. ISSN 0556-2813. 87(1). doi: 10.1103/PhysRevC.87.014319. Fulltekst i vitenarkiv Vis sammendrag

  The level densities and γ-ray strength functions of 105,106,111,112Cd have been extracted from particle-γ coincidence data using the Oslo method. The level densities are in very good agreement with known levels at low excitation energy. The γ-ray strength functions display no strong enhancement for low γ energies. However, more low-energy strength is apparent for 105,106Cd than for 111,112Cd. For γ energies above ≈4 MeV, there is evidence for some extra strength, similar to what has been previously observed for the Sn isotopes. The origin of this extra strength is unclear; it might be due to E1 and M1 transitions originating from neutron skin oscillations or the spin-flip resonance, respectively. © 2013 American Physical Society

• Ducasse, Q; Jurado, B; Aiche, M; Mathieu, L; Tornyi, Tamas Gabor & Görgen, Andreas [Vis alle 28 forfattere av denne artikkelen] (2013). Neutron-induced cross sections of actinides via the surrogate-reaction method. The European Physical Journal Conferences. ISSN 2101-6275. 42. doi: 10.1051/epjconf/20134201003. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Bernstein, Lee; Bürger, Alexander; Görgen, Andreas; Gunsing, Frank & Hagen, Trine Wiborg [Vis alle 11 forfattere av denne artikkelen] (2013). Observation of large orbital scissors strength in actinides. Acta Physica Polonica B. ISSN 0587-4254. 44(3), s. 567–570. doi: 10.5506/APhysPolB.44.567. Fulltekst i vitenarkiv
• Wilson, J.N.; Gunsing, Frank; Bernstein, Lee; Bürger, Alexander; Görgen, Andreas & Guttormsen, Magne Sveen [Vis alle 13 forfattere av denne artikkelen] (2012). Level Densities in the actinide region and indirect (n,gamma) cross section measurements using the surrogate method. The European Physical Journal Conferences. ISSN 2101-6275. 21. doi: 10.1051/epjconf/20122101003. Fulltekst i vitenarkiv
• Wilson, J.N.; Gunsing, F.; Bernstein, L.A.; Bürger, Alexander; Görgen, Andreas & Guttormsen, Magne Sveen [Vis alle 16 forfattere av denne artikkelen] (2012). Indirect (n, gamma) cross sections of thorium cycle nuclei using the surrogate method. Physical Review C. Nuclear Physics. ISSN 0556-2813. 85(3). doi: 10.1103/PhysRevC.85.034607. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Bernstein, Lee; Bürger, Alexander; Görgen, Andreas; Gunsing, Frank & Hagen, Trine Wiborg [Vis alle 11 forfattere av denne artikkelen] (2012). Observation of Large Scissors Resonance Strength in Actinides. Physical Review Letters. ISSN 0031-9007. 109(16). doi: 10.1103/PhysRevLett.109.162503. Fulltekst i vitenarkiv Vis sammendrag

  The orbital M1 scissors resonance has been measured for the first time in the quasicontinuum of actinides. Particle-γ coincidences are recorded with deuteron and 3He-induced reactions on 232Th. The residual nuclei 231,232,233Th and 232,233  Pa show an unexpectedly strong integrated strength of BM1=11–15μ2n in the Eγ=1.0–3.5  MeV region. The increased γ-decay probability in actinides due to scissors resonance is important for cross-section calculations for future fuel cycles of fast nuclear reactors and may also have an impact on stellar nucleosynthesis. © 2012 American Physical Society

• Hagen, Trine Wiborg; Lopez-Martens, A.; Hauschild, K; Belozerov, A. V.; Chelnokov, M. L. & Chepigin, V. I. [Vis alle 32 forfattere av denne artikkelen] (2011). SPECTROSCOPY OF TRANSFERMIUM NUCLEI USING THE GABRIELA SETUP. Acta Physica Polonica B. ISSN 0587-4254. 42(3-4), s. 605–608. doi: 10.5506/APhysPolB.42.605. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Goriely, Stephane; Algin, Emel; Agvaanluvsan, Undraa; Bürger, Annetta & Görgen, Andreas [Vis alle 22 forfattere av denne artikkelen] (2011). Gamma-ray strength functions and their relation to astrophysics. AIP Conference Proceedings. ISSN 0094-243X. 1377, s. 239–246. doi: 10.1063/1.3628386. Fulltekst i vitenarkiv
• Lopez-Martens, A; Hagen, Trine Wiborg; Görgen, Andreas; Guttormsen, Magne Sveen; Lønnroth, Tom & Nyhus, Hilde-Therese [Vis alle 9 forfattere av denne artikkelen] (2011). Spectroscopy of 253No and its daughters. Nuclear Physics A. ISSN 0375-9474. 852, s. 15–15. Fulltekst i vitenarkiv
• Hauschild, Karl; Lopez-martens, A.; Hagen, Trine Wiborg; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie & Nyhus, Hilde-Therese [Vis alle 10 forfattere av denne artikkelen] (2010). Spectroscopy of transfermium nuclei using the GABRIELA set up at the focal plane of the VASSILISSA recoil separator. AIP Conference Proceedings. ISSN 0094-243X. 1224, s. 269–278. doi: 10.1063/1.3431424. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Hagen, Trine Wiborg (2023). Nuclear weapons - current status. Fulltekst i vitenarkiv
• 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. 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.

• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Blasi, N; Bracco, A; Camera, F & Eriksen, Tomas Kvalheim [Vis alle 19 forfattere av denne artikkelen] (2014). Recent results using large LaBr3 detectors and future perspectives. Fulltekst i vitenarkiv
• Tveten, Gry Merete; Campo, L.C.; Eriksen, Tomas Kvalheim; Giacoppo, Francesca; Guttormsen, Magne Sveen & Görgen, Andreas [Vis alle 17 forfattere av denne artikkelen] (2014). The statistical properties of Sn-isotopes studied with the Oslo-method. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Bernstein, Lee; Bürger, Alexander; Görgen, Andreas; Gunsing, Frank & Hagen, Trine Wiborg [Vis alle 11 forfattere av denne artikkelen] (2013). Scissors strength in the quasi-continuum of actinides. Fulltekst i vitenarkiv
• Görgen, Andreas; Hagen, Trine Wiborg; Salsac, M.-D.; Grente, L.; Farget, F. & Sulignano, B [Vis alle 29 forfattere av denne artikkelen] (2012). Collectivity of neutron-rich nuclei Novel techniques to measure lifetimes of excited states. Fulltekst i vitenarkiv
• Guttormsen, Magne Sveen; Bernstein, Lee; Bürger, Alexander; Görgen, Andreas; Gunsing, Frank & Hagen, Trine Wiborg [Vis alle 11 forfattere av denne artikkelen] (2012). Observation of large orbital scissors strength in actinides. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Bürger, Alexander; Eriksen, Tomas Kvalheim; Görgen, Andreas; Guttormsen, Magne Sveen & Hagen, Trine Wiborg [Vis alle 29 forfattere av denne artikkelen] (2011). Experiments of reaction model inputs: level density and gamma strength. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Bürger, Alexander; Eriksen, Tomas Kvalheim; Görgen, Andreas & Hagen, Trine Wiborg [Vis alle 16 forfattere av denne artikkelen] (2011). Level density and gamma strength - achievements and challenges. Fulltekst i vitenarkiv

Se alle arbeider i NVA