Neutronic simulations for source-instrument matching at the Lujan Center

The neutronics design of pulsed spallation neutron sources can be difficult when considering the fact that multiple instruments view the same moderator. Typically, the moderator design is a compromise between the required resolution for one instrument and the maximum intensity desires of another instrument. At the Manuel Lujan, Jr., Neutron Scattering Center (MLNSC), a recent target redesign has offered the opportunity to design a moderator for a Laue diffractometer with few other requirements. Detailed time and energy spectra were calculated for a variety of moderator decoupling options. The purpose of this summary is to document the neutronics calculations required for this source-instrument matching process.