Neutron scattering off even gadolinium isotopes: differential cross sections

Abstract This study investigates neutron differential scattering cross sections off even Gadolinium isotopes (Gd-156, Gd-158, Gd-160) at various energies (1.5, 2.5, 4.1, and 7 MeV), comparing theoretical calculations with evaluations from prominent nuclear data libraries (ENDF/B-VIII.0, JENDL-5 and EXFOR) and available experimental data. Analysis reveals a characteristic maximum for the forward angles and a deep minimum in the angular distributions, thus indicating quasi-forbidden scattering angle range. Both theoretical and ENDF/B-VIII.0 results show excellent agreement in the forward direction at 1.5 MeV. However, discrepancies emerge at higher energies, particularly at 2.5 MeV, where neither ENDF/B-VIII.0 or JENDL-5 accurately reproduce experimental data, especially for Gd-160. Notably, the rotational nature of Gd-160, as indicated by its low first excited state energy and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <m:mrow> <m:msup> <m:mi>E</m:mi> <m:msup> <m:mn>4</m:mn> <m:mo>+</m:mo> </m:msup> </m:msup> <m:mo>/</m:mo> <m:msup> <m:mi>E</m:mi> <m:msup> <m:mn>2</m:mn> <m:mo>+</m:mo> </m:msup> </m:msup> </m:mrow> </m:math> ${E}^{{4}^{+}}/{E}^{{2}^{+}}$ ratio, is not consistently reflected in the ENDF/B-VIII.0 VIII.0 evaluations. For 4.1 MeV, JENDL-5 demonstrates superior agreement with experimental data compared to ENDF/B-VIII.0 and theoretical calculations. At 7 MeV, multiple minima are observed in both theoretical and ENDF/B-VIII.0 results, predicting specific angular intervals with near-zero scattering. While theoretical calculations generally align with experimental and evaluated data at forward angles, deviations occur at backward angles, likely due to increased compound nucleus contributions. Despite the limited experimental data, particularly the reliance on Bauge’s team measurements, this study underscores the utility of theoretical models in providing structural insights into neutron scattering cross sections for deformed nuclei.