Monte-Carlo simulation codes development and their applications to neutron optical devices and neutron scattering instruments

Abstract We incorporated magnetic and gravitational interactions into the neutronic code “PHITS” developed at JAERI, which is the unified code of the high-energy particle-transport code NMTC/JAERI and MCNP-type low energy code. Using the code, inelastic and multiple-scattering effects in water sample for SANS experiment was demonstrated. Numerical simulation of focusing SANS instrument that has a sextupole magnet has been conducted, and the spin-flip processes in the non-adiabatic region along the central region of the magnet were clearly observed. Gravitational effects were also evaluated.