%0 Journal Article
%T First determination of beta-delayed multiple neutron emission beyond A=100 through direct neutron measurement: The P-2n value of Sb-136
%A Caballero-Folch, R. et al
%A Agramunt, J.
%A Tain, J. L.
%A Algora, A.
%A Domingo-Pardo, C.
%A Guadilla, V.
%A Montaner-Piza, A.
%A Orrigo, S. E. A.
%A Rubio, B.
%A Tarifeño-Saldivia, A.
%A Tolosa-Delgado, A.
%J Physical Review C
%D 2018
%V 98
%N 3
%I Amer Physical Soc
%@ 2469-9985
%G English
%F Caballero-Folch_etal2018
%O WOS:000444207600003
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=3728), last updated on Tue, 13 Oct 2020 12:50:59 +0000
%X Background: beta-delayed multiple neutron emission has been observed for some nuclei with A <= 100 being the Rb-100 the heaviest beta 2n emitter measured to date. So far only 25 P-2n values have been determined for the approximate to 300 nuclei that may decay in this way. Accordingly it is of interest to measure P-2n values for the other possible multiple neutron emitters throughout the chart of the nuclides. It is of particular interest to make such a measurement for nuclei with A > 100 to test the predictions of theoretical models and simulation tools for the decays of heavy nuclei in the region of very neutron-rich nuclei. In addition the decay properties of these nuclei are fundamental for the understanding of astrophysical nucleosynthesis processes such as the r-process and safety inputs for nuclear reactors. Purpose: To determine for the first time the two-neutron branching ratio the P-2n value for Sb-136 through a direct neutron measurement and to provide precise P-1n values for Sb-136 and Te-136. Method: A pure beam of each isotope of interest was provided by the JYFLTRAP Penning trap at the Ion Guide Isotope Separator On-Line (IGISOL) facility of the University of Jyvaskyla Finland. The purified ions were implanted into a moving tape at the end of the beam line. The detection setup consisted of a plastic scintillator placed right behind the implantation point after the tape to register the beta decays and the BELEN detector based on neutron counters embedded in a polyethylene matrix. The analysis was based on the study of the beta- and neutron-growth-and-decay curves and the beta-one-neutron and beta-two-neutron time correlations which allowed us the determination of the neutron branching ratios. Results: The P-2n value of Sb-136 was found to be 0.14(3)% and the measured P-1n values for Sb-136 and Te-136 were found to be 32.2(15)% and 1.47(6)% respectively. Conclusions: The measured P-2n value is a factor 44 smaller than predicted by the finite-range droplet model plus the quasiparticle random-phase approximation (FRDM+QRPA) model used for r-process calculations.
%R 10.1103/PhysRevC.98.034310
%U http://arxiv.org/abs/1803.07205
%U https://doi.org/10.1103/PhysRevC.98.034310
%P 034310-10pp