Recent results from the measurement of $\beta $ delayed neutron emitters

The $\beta $-delayed neutron emission probability of very exotic nuclei is crucial for the understanding of nuclear structure properties of many isotopes, and astrophysical processes such as the rapid neutron-capture process (r-process). The production of neutron-rich isotopes at present RIB facilities allowed to measure $\beta $-delayed one-neutron emitters ($\beta $1n) up to regions around mass A\textasciitilde 150, and recently up to masses heavier than A$=$210, beyond the N$=$126 shell closure. It has been a long-standing challenge to measure more exotic species with $\beta $-delayed multiple-neutron emitting branches due to the low production rates, and thus the heaviest $\beta $2n detected so far are $^{\mathrm{98,100}}$Rb. This contribution will present preliminary results of a recent experiment performed at the IGISOL facility of the University of Jyv\"{a}skyl\"{a} (Finland), to produce $^{\mathrm{136}}$Sb, the heaviest multiple-neutron emitter measured so far. $^{\mathrm{136}}$Sb is present in the freeze-out of the r-process and contributes to the second abundance peak around N\textasciitilde 82 in the A$=$130 mass region.