  The quest for improved neutron capture cross sections for advanced reactor
concepts, transmutation of radioactive wastes as well as for astrophysical
scenarios of neutron capture nucleosynthesis has motivated new experimental
efforts based on modern techniques. Recent measurements in the keV region have
shown that a 4p BaF2 detector represents an accurate and versatile instrument
for such studies. The present work deals with the potential of such a 4p BaF2
detector in combination with spallation neutron sources, which offer large
neutron fluxes over a wide energy range. Detailed Monte Carlo simulations with
the GEANT package have been performed to investigate the critical backgrounds
at a spallation facility, to optimize the detector design, and to discuss
alternative solutions.
