  Beta-delayed neutron emission is important for nuclear structure and
astrophysics as well as for reactor applications. Significant advances in
nuclear experimental techniques in the past two decades have led to a wealth of
new measurements that remain to be incorporated in the databases. We report on
a coordinated effort to compile and evaluate all the available beta-delayed
neutron emission data. The different measurement techniques have been assessed
and the data have been compared with semi-microscopic and
microscopic-macroscopic models. The new microscopic database has been tested
against aggregate total delayed neutron yields, time-dependent group parameters
in 6-and 8-group re-presentation, and aggregate delayed neutron spectra. New
recommendations of macroscopic delayed-neutron data for fissile materials of
interest to applications are also presented. The new Reference Database for
Beta-Delayed Neutron Emission Data is available online at:
http://www-nds.iaea.org/beta-delayed-neutron/database.html.
