  Neutron energy spectrum measurements from a solid methane moderator were
performed at the Low Energy Neutron Source (LENS) at Indiana University
Cyclotron Facility (IUCF) to verify our neutron scattering model of solid
methane. The time-of-flight method was used to measure the energy spectrum of
the moderator in the energy range of 0.1$meV\sim$ 1$eV$. Neutrons were counted
with a high efficiency $^{3}{He}$ detector. The solid methane moderator was
operated in phase II temperature and the energy spectra were measured at the
temperatures of 20K and 4K. We have also tested our newly-developed scattering
kernels for phase II solid methane by calculating the neutron spectral
intensity expected from the methane moderator at the LENS neutron source using
MCNP (Monte Carlo N-particle Transport Code). Within the expected accuracy of
our approximate approach, our model predicts both the neutron spectral
intensity and the optimal thickness of the moderator at both temperatures. The
predictions are compared to the measured energy spectra. The simulations agree
with the measurement data at both temperatures.
