Among the main missions of modern radioactive isotope facilities is the exploration of properties of yet unknown isotopes on the neutron-rich side of the chart of nuclides. However, going more neutron-rich also means that the neutron separation energy decreases until it reaches the dripline at Sn = 0 MeV. If the neutron separation energy gets lower than the β-decay energy window (Qβ value), a new decay mechanism can occur: the emission of neutrons after β-decay. These “β-delayed neutron” (βn) emitters play a crucial role in nuclear structure, nuclear astrophysics, and for nuclear reactor applications. [ABSTRACT FROM AUTHOR]