%0 Journal Article
%T β-delayed neutron emissions from N > 50 gallium isotopes
%A Yokoyama, R. et al
%A Tain, J. L.
%A Algora, A.
%A Agramunt, J.
%A Domingo-Pardo, C.
%A Morales, A. I.
%A Rubio, B.
%A Tolosa-Delgado, A.
%J Physical Review C
%D 2023
%V 108
%N 6
%I Amer Physical Soc
%@ 2469-9985
%G English
%F Yokoyama_etal2023
%O WOS:001159167500001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5939), last updated on Sun, 18 Feb 2024 19:02:15 +0000
%X beta-delayed gamma-neutron spectroscopy has been performed on the decay of A=84 to 87 gallium isotopes at the RI-beam Factory at the RIKEN Nishina Center using a high-efficiency array of 3He neutron counters (BRIKEN). beta-2n-gamma events were measured in the decays of all of the four isotopes for the first time, which is direct evidence for populating the excited states of two-neutron daughter nuclei. Detailed decay schemes with the gamma branching ratios were obtained for these isotopes, and the neutron emission probabilities (P-xn) were updated from the previous study. Hauser-Feshbach statistical model calculations were performed to understand the experimental branching ratios. We found that the P-1n and P-2n values are sensitive to the nuclear level densities of 1n daughter nuclei and showed that the statistical model reproduced the P-2n/P-1n ratio better when experimental levels plus shell-model level densities fit by the Gilbert-Cameron formula were used as the level-density input. We also showed the neutron and gamma branching ratios are sensitive to the ground-state spin of the parent nucleus. Our statistical model analysis suggested J <= 3 for the unknown ground-state spin of the odd-odd nucleus Ga-86, from the I gamma(4(+)-> 2(+))/I-gamma(2(+)-> 0(+)) ratio of Ga-84 and the P-2n/P-1n ratio. These results show the necessity of detailed understanding of the decay scheme, including data from neutron spectroscopy, in addition to gamma measurements of the multineutron emitters.
%R 10.1103/PhysRevC.108.064307
%U https://doi.org/10.1103/PhysRevC.108.064307
%P 064307-15pp