sabinama

• 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 Vis sammendrag

  The cascading 3.21 and 4.44 MeV electric quadrupole transitions have been observed from the Hoyle state at 7.65 MeV excitation energy in 12C, excited by the 12C(p,p′) reaction at 10.7 MeV proton energy. From the proton-γ−γ triple coincidence data, a value of Γrad/Γ=6.2(6)×10−4 was obtained for the radiative branching ratio. Using our results, together with ΓE0π/Γ from Eriksen et al. [Phys. Rev. C 102, 024320 (2020)] and the currently adopted Γπ(E0) values, the radiative width of the Hoyle state is determined as Γrad=5.1(6)×10−3  eV. This value is about 34% higher than the currently adopted value and will impact models of stellar evolution and nucleosynthesis.

• Maharramova, Sabina; Beere, William H. Åstorp; Eitrheim, Knut Kjærand Frellumstad; Reistad, Ole & Walderhaug, Tord (2018). Comparison of HELIOS-2.1 and SCALE-6.1 codes on pin-cell model. Annals of Nuclear Energy. ISSN 0306-4549. 117, s. 155–164. doi: 10.1016/j.anucene.2018.03.026. Fulltekst i vitenarkiv Vis sammendrag

  Deterministic HELIOS-2.1 and SCALE-6.1 codes are compared using pin-cell models for light water reactor (LWR) and heavy water reactor (HWR) cases. The main objective of this study is to identify the origins of any discrepancies between compared codes. The infinite multiplication factor kinf, flux distribution, absorption, fission, production reaction rates, and burn-up dependent concentrations of major fuel isotopes, are investigated herein and compared. Comparison of kinf has shown that the codes are in good agreement for both the LWR and HWR cases. The codes showed differences in the isotope number density of up to 6% in the case of prominent isotopes, and for 235U and 239Pu at 60 GWd/tU in the LWR case. These differences were, approximately 20% for 235U and 30% for 239Pu in the HWR case. It is concluded that these discrepancies are attributed to differences in the modelling of the thermalisation process in the HWR case. This needs to be investigated further to determine the root cause. Possible causes could be the neutron group structure, cross section condensation, treatment of up-scatter, angle dependence of scatter, and spatial homogenisation during source iterations.

• 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.

Se alle arbeider i NVA