  $Background:$ Previous measurements of $\beta$-delayed neutron emitters
comprise around 230 nuclei, spanning from the $^{8}$He up to $^{150}$La. Apart
from $^{210}$Tl, with a minuscule branching ratio of 0.007\%, no other neutron
emitter is measured yet beyond $A=150$. Therefore new data are needed,
particularly in the heavy mass region around N=126, in order to guide
theoretical models and to understand the formation of the third r-process peak
at $A\sim195$.
  $Purpose:$ To measure both, $\beta$-decay half-lives and neutron branching
ratios of several neutron-rich Au, Hg, Tl, Pb and Bi isotopes beyond $N=126$.
  $Method:$ Ions of interest are produced by fragmentation of a $^{238}$U beam,
selected and identified via the GSI-FRS fragment separator. A stack of
segmented silicon detectors (SIMBA) is used to measure ion-implants and
$\beta$-decays. An array of 30 $^3$He tubes embedded in a polyethylene matrix
(BELEN) is used to detect neutrons with high efficiency and selectivity. A
self-triggered digital system is employed to acquire data and to enable
time-correlations. The latter are analyzed with an analytical model and results
for the half-lives and neutron-branching ratios are derived using the binned
Maximum-Likelihood method.
  $Results:$ Twenty new $\beta$-decay half-lives are reported for
$^{204-206}$Au, $^{208-211}$Hg,$^{211-216}$Tl,$^{215-218}$Pb and
$^{218-220}$Bi, nine of them for the first time. Neutron emission probabilities
are reported for $^{210,211}$Hg and $^{211-216}$Tl.
  $Conclusions:$ The new $\beta$-decay half-lives are in good agreement with
previous measurements in this region. The measured neutron emission
probabilities are comparable or smaller than values predicted by global models
like RHB+RQRPA.

Nuclear Experiment