Neutron capture experiments at LLNL

A large 25.4 by 30.48 cm NaI spectrometer has been built at the Lawrence Livermore National laboratory to perform neutron capture experiments. The High Energy Gamma Ray Spectrometer (HEGRS) has good energy resolution and timing resolution ({approx}2 ns FWHM). This time resolution is sufficient to discriminate against neutrons with energies up to {approx} 30 MeV. The anti-coincidence shield has been shown to be 98-99 % efficient over a wide energy range. Angular distributions and cross sections have been taken for neutron capture on various targets, Preliminary results will be discussed.