Virtual experiments in a nutshell: Simulating neutron scattering from materials within instruments with McStas

We introduce Monte-Carlo methods for neutron scattering with step-by-step examples, using the McStas simulation tool. A selection of neutron instrument components are presented, as well as available sample scattering kernels. All these parts are assembled into more advanced instrument models in order to produce so-called virtual experiments, that is simulations which produce results comparable with experiments. Ways to couple such simulations with other simulation software including molecular dynamics are discussed.