Soft-rotator Model Analysis of Collective Band Structures of Even-even Actinide Nuclei.

Abstract

Positive-parity collective band structures of low-lying levels in even-even actinide nuclei were analyzed based on an extension of the Davydov-Chaban soft rotator model, which accounts for the rotation and b-and g -vibrations of even-even nuclei with non-axial quadrupole deformation . The parameters to reproduce the 4-bands, i.e., the ground-state rotational band, the Kr_??_2 band, and the nb=1 and n-g=1 bands, were obtained, and their systematic trends were deduced. Based on this result the unassigned band having a sequence of 0+, 2+, 4+,.., which is observed in many actinide nuclei, was assigned likely to be the nb=1 band. The systematic trends of the parameters found in this work could be a guide to estimate the collective band structure of nuclei for which such data are poorly known. The correct assignment of collective levels was found to be important for the calculation of neutron inelastic scattering cross sections.

Angular distributions of protons scattered byAr40nuclei with excitation of the2+(1.46 MeV) andOkumuşoğlu1, Görür2, Bírchall3 et al. 2007Phys. Rev. C4020View full textAdd to dashboardCite

“…As shown in Table I, the softness of the 40 Ar nucleus to quadrupole deformations, µ β 20 , is found to be rather large, namely 2.0585. Typical rotational nuclei such as actinides have µ β 20 values of 0.1 to 0.3 [26], and 56 Fe has a value of about 0.5 [27]. The larger µ β 20 signifies that a nucleus is soft to quadrupole deformation.…”

General-purpose Nuclear Data Library JENDL-5 and to the Next

“…New evaluations were made including stable and unstable nuclei: 7,10 Be, 11, 14 C, 17,18 O, [20][21][22] Ne, 22,24 Na, 28 Mg, 26 Al, and 31,32 Si. JENDL-4.0 basically provides isotopic data, but the data for carbon still remained in elemental data.…”

“…12 The theoretical model reaction code CCONE, 23 which was widely used in the JENDL-5 evaluation, was upgraded by adding a new function that enable us to calculate recoil energy spectra of residual nuclei and by taking into account the multiple particle emissions for high energy reactions. 24 The recoil energy spectra were missing in high energy files such as JENDL-4.0/HE and JENDL/ImPACT-2018, but JENDL-5 overcame the problem that arose from those missing data. Figure 6 shows the calculated results of the DPA cross section due to neutron induced reaction on 56 Fe.…”

“…Regarding the neutron induced reaction files, two special-purpose files of JENDL/AD-2017 3 and JENDL/ImPACT-2018 4 were recently released to nuclear backend applications of activation evaluation for nuclear facilities and system development on nuclear transmutations of high-level radioactive wastes of long-lived fission products, respectively. Furthermore, the photon, proton, and deuteron induced reaction files were released as JENDL/PD-2016.1, 5 JENDL-4.0/HE, 6 and JENDL/DEU-2020, 7 respectively, for accelerator applications. While sufficient data were provided to users, the increase in the number of the libraries would bring defects such as inconsistencies among the data in the libraries and confusion on the use of proper data.…”

Evaluation of covariance data in JENDL

“…The covariance was used to increase the accuracy of the calculation for the fast reactors by means of nuclear data adjustment methods [4,5]. Recently, the covariance data were also utilized to estimate the uncertainties for an innovative reactor, e.g., for accelerator-driven system [6]. In addition, to promote the use of the covariance data, a couple of working groups: Covariance Utilization WG (2011-2017), and Covariance Data Utilization and Promotion WG (2018-2020) were organized under the JENDL Committee (one of successors of the former Sigma Committee).…”