MCNP SIMULATIONS OF NEUTRON MODERATION IN THE IPNS C-MODERATOR

We have used the MCNP code to simulate neutron moderation in the IPNS target/moderator assembly. The goal of this study was to investigate t he effect of groove configuration on neutron leakage from the C modera tor. This moderator supplies low energy neutrons to four low-Q elastic scattering instruments; two reflectometers and two SANS instruments. The current horizontally grooved configuration is not optimized for th e two vertical-slit-geometry reflectometers. This study resulted in a more optimized groove configuration. (C) 1998 Published by Elsevier Sc ience B.V. All rights reserved.