28-30 November 2019
C-CUBE, Kyushu University Chikushi Campus 九州大学筑紫キャンパス総合研究棟 (C-Cube)
Asia/Tokyo timezone
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九州大学筑紫キャンパス総合研究棟 (C-Cube) - 3階広場

Systematical calculation of probabilities of beta-delayed neutron emission and fission in the entire region of nuclear chart


  • Dr. Hiroyuki KOURA

Primary authors





In the very neutron-rich nuclei, the beta-decay occurs with some accompanying process as neutron emissions, and fission. The beta-decayed neutron process is an important phenomenon for manipulating nuclear reactor, and the beta-delayed fission critically affects the termination of the r-process nucleosynthesis in stars. We performed a systematical calculation of probabilities of beta-delayed neutron and beta-delayed fission with the improved gross theory of beta-decay [1,2] and the KTUY mass model [3,4] in the entire region of nuclear chart. The calculated probabilities of beta-delayed neutron emissions are compared with experimental ones for over 200 nuclides. Regarding the delayed fission, we only give calculated ones because there are no experimental data.
In the landscape of fission-barrier height with the KTUY mass model in super- and extremely super-heavy mass region, the “conventional” island of stability is found near nuclei with Z=114 and N=184, while there is “peninsula” along N=228 [5]. The N=228 peninsula is caused by single-particle shell gap of N=228 appears in Ref [4]. The beta-delayed fission probabilities are calculated with the fission barriers and a beta-decay model, the gross theory. There are some regions with large fission probabilities as avoided along N=228. These fission probabilities affect the abundance from the r-process and also determines the creation of super-heavy element in nature. This work was financially supported by the Japan Society for the Promotion of Science KAKENHI (Grants No. 18K03631 and No. 17H06090) as a program ‘Effects of fission to isotopic abundances on the r-process synthesis in star’ and ‘Study of the origin of heavy elements using an innovative mass spectrograph’.

References [1] H. Koura and S. Chiba, Phys. Rev. C 95, 064304 (2017). [2] F. Endo and H. Koura, Phys. Rev. C 99, 034303 (2019). [3] H. Koura, et al., Prog. Theor. Phys. 113, 305 (2005) [4] H. Koura and S. Chiba, J. Phys. Soc. Jpn. 82, 014201 (2013). [5] H. Koura, Prog. Theor. Exp. Phys. 2014, 113D02 (2014).