Lauren Tracy Bell

• Bell, Lauren Tracy; Siem, Sunniva; Larsen, Ann-Cecilie; Bürger, A.; Markova, Maria & Ingeberg, V. W. [Vis alle 12 forfattere av denne artikkelen] (2026). Extracting the nuclear level density and γ-ray strength function of 90Zr. Physical Review C. ISSN 2469-9985. 114(1). doi: 10.1103/p9y9-xxjf. Fulltekst i vitenarkiv Vis sammendrag

  In this work, we have extracted the nuclear level density (NLD) and 𝛾-ray strength function (𝛾⁢SF) using the Oslo method on particle-𝛾 coincidence data from the 90Zr⁢(𝑝,𝑝′⁢𝛾)90Zr ⁢reaction. We have applied the shape method to the same data set, providing a model-independent 𝛾⁢SF and a cross-check on the slope of the Oslo-method NLD and 𝛾⁢SF. Further, we have combined the 𝛾⁢SF from this work with photonuclear data, thus covering the 2.5<𝐸𝛾<18MeV energy range. We see an increase in strength in the region around 𝐸𝛾≈9MeV, consistent with previous (𝛾,𝛾′) and (𝛾,𝑛) data. On the other hand, surprisingly, we do not observe a strong low-energy increase at low transition energies. The resulting NLD and 𝛾⁢SF were used as inputs to the nuclear reaction code talys to estimate the cross sections and astrophysical reaction rates for the 89Zr(𝑛,𝛾)⁢90Zr 89Y⁡(𝑝,𝛾)90Zr reactions. We find good agreement with available experimental cross sections and JINA calculations for the 89Y⁡(𝑝,𝛾) results, but not for the 89Zr⁢(𝑛,𝛾) reaction rate for stellar temperatures above 0.7 GK. Based on our data, we provide a much more narrow uncertainty band for the 89Zr⁢(𝑛,𝛾) cross section and reaction rate.

• Markova, Maria; Larsen, Ann-Cecilie; Neumann-Cosel, P. von; Litvinova, E.; Goriely, S. & Bell, Lauren Tracy [Vis alle 17 forfattere av denne artikkelen] (2026). Exploring the statistical properties of the neutron-deficient 109In isotope with the Oslo method. Physical Review C. ISSN 2469-9985. 113(4). doi: 10.1103/qrvh-s12k. Fulltekst i vitenarkiv Vis sammendrag

  The nuclear level density and the 𝛾-ray strength function of the neutron-deficient 109In isotope were extracted for the first time with data from the 106Cd⁢(𝛼,𝑝⁢𝛾)⁢109In reaction using a combination of the Oslo and the shape methods. Both quantities are consistent with those of neighboring Cd and Sn nuclei but show substantial discrepancies with currently available model predictions. In contrast to earlier observations in the neighboring isotopic chains, 109In does not exhibit any significant enhancement of the dipole strength near the neutron separation energy. To interpret this feature, random-phase time-blocking approximation calculations have been performed for 109In and the neighboring 110,112Sn nuclei. The experimental data were also employed to estimate cross sections and rates of the radiative neutron- and proton-capture reactions, 108In⁢(𝑛,𝛾)⁢109In and 108Cd⁢(𝑝,𝛾)⁢109In, respectively, with the reaction code talys. Our (𝑝,𝛾) cross section is in excellent agreement with direct measurements over a wide range of proton energies, while the (𝑛,𝛾) cross section demonstrates notable deviations from predictions in the jina reaclib library. The new results on the statistical properties of 109In provide valuable constraints that may help address the problem of large model uncertainties compromising the accuracy of astrophysical 𝑝-process simulations.

Se alle arbeider i NVA

• Bell, Lauren Tracy (2024). Nuclear level densities and gamma-ray strength functions for two well deformed even-even samarium isotopes. Fulltekst i vitenarkiv
• Bell, Lauren Tracy (2024). Investigating the nuclear level density and gamma strength function of two well deformed even-even samarium isotopes (152,154Sm) and 90Zr. Fulltekst i vitenarkiv
• Bell, Lauren Tracy (2024). Nuclear level densities and gamma strength functions of 152,154Sm. Fulltekst i vitenarkiv
• Bell, Lauren Tracy (2023). Dipole Resonances in the Well-Deformed Even-even Samarium (152Sm and 154Sm) Isotopes. Fulltekst i vitenarkiv

Se alle arbeider i NVA