The software package \MCS is a tool for carrying out Monte Carlo
ray-tracing simulations of neutron scattering instruments with high
complexity and precision. The simulations can compute most aspects of the
performance of instruments and samples
and can thus be used to optimize the use of existing equipment,
design new instrumentation, and carry out full virtual experiments.
\MCS is based on a unique design where an automatic compilation process
translates high-level textual instrument descriptions into efficient
ISO-C code. This design makes it simple to set up typical simulations
and also gives essentially unlimited freedom to handle more unusual
cases.

This report constitutes the component manual for \MCS, and,
together with the manual for the \MCS system, it
contains full documentation of all aspects of the program. It covers
a description of all official components of the \MCS package with
some theoretical background. Selected test
instruments and representative \MCS simulations performed with these
instruments are described in the User Manual.

