Thu·Apr 28, 2022Thursday·April 28, 2022

1. 01*

   Evaporation Residue Production in Complete and Incomplete Fusion Reactions of Ne-20 with Au-197 and Ho-165 at E = 14.9 x AMeV

   Fritz Peter Heßberger

   Velocity distributions of heavy residues (A_Res > A_Tar), produced in irradiations of Au-197 and Ho-165 with Ne-20 at bombarding energies of E = 208 MeV, have been measured at the velocity filter SHIP. While for the products from Ne-20 + Ho-165 just a mean value of v/v_CN = 0.91+-0.01 was obtained, individual residues, attributed to isotopes of astatine and polonium with mass numbers ranging from A=195 to A=203 could be identified by means of alpha - spectroscopy in the bombardments Au-197. A linear increase of the mean velocity from v/v_CN = 0.85 to v/v_CN = 0.93 with decreasing residue mass was observed. This effect was attributed to an increasing contribution of pre-equilibrium particle emission to the production of heavy residues. A quantititative estimation resulted in a 90 % contribution of pre-equilibrium processes to the production of astatine isotopes, and a 50 % contribution to the polonium isotopes.

   nucl-ex0 citations
2. 02*

   EXFOR-based simultaneous evaluation of neutron-induced uranium and plutonium fission cross sections for JENDL-5

   Naohiko Otuka🇦🇹 · Osamu Iwamoto🇯🇵

   The neutron-induced fission cross sections were simultaneously evaluated for the JENDL-5 library for ${}^{233,235}$U and ${}^{239,241}$Pu from 10 keV to 200 MeV and for ${}^{238}$U and ${}^{240}$Pu from 100 keV to 200 MeV. Evaluation was performed by least-squares fitting of Schmittroth's roof function to the logarithms of the experimental cross sections and cross section ratios in the EXFOR library. A simultaneous evaluation code SOK was used with its extension to data in arbitrary unit. The outputs of the code were adopted as the evaluated cross sections without any further corrections. The newly obtained evaluated cross sections were compared with the evaluated cross sections in the JENDL-4.0 library and the IAEA Neutron Data Standards 2017. The evaluated cross sections were also validated against the californium-252 spontaneous fission neutron spectrum averaged cross sections, $\Sigma \Sigma$ (coupled thermal/fast uranium and boron carbide spherical assembly) neutron spectrum averaged cross sections, and small-sized LANL fast system criticalities. The changes in the obtained evaluated cross sections from those in the JENDL-4.0 library are within 4% (${}^{241}$Pu), 3% (${}^{233}$U, ${}^{240}$Pu), or 2% (${}^{235}$U, ${}^{239}$Pu). The newly evaluated ${}^{235}$U, ${}^{238}$U and ${}^{239}$Pu cross sections agree with the IAEA Neutron Data Standards 2017 within 2% with some exceptions.

   nucl-exSci.Technol.(2022)·8 citations
3. 03*

   Ab initio studies of double Gamow-Teller transition and its correlation with neutrinoless double beta decay

   J. M. Yao🇨🇳 · I. Ginnett🇨🇦 · A. Belley🇨🇦 · T. Miyagi🇩🇪 · R. Wirth🇺🇸 · S. Bogner🇺🇸 · J. Engel🇺🇸 · H. Hergert🇺🇸 · J. D. Holt🇨🇦 · S. R. Stroberg🇺🇸

   We use chiral interactions and several {\em ab initio} methods to compute the nuclear matrix elements (NMEs) for ground-state to ground-state double Gamow-Teller transitions in a range of isotopes, and explore the correlation of these NMEs with those for neutrinoless double beta decay produced by the exchange of a light Majorana neutrino. When all the NMEs of both isospin-conserving and isospin-changing transitions from the {\em ab initio} calculations are considered, the correlation is strong. For the experimentally relevant isospin-changing transitions by themselves, however, the correlation is weaker and may not be helpful for reducing the uncertainty in the NMEs for neutrinoless double-beta decay.

   ↳ nucl-thhep-phnucl-exPRC(2022)·28 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.