  The experiment aiming at the simultaneous determination of the two
transversal polarisation components of electrons emitted in the decay of free,
polarised neutrons is in progress at the Paul Scherrer Institute (Villigen,
Switzerland). The non-zero value of R coefficient, proportional to the
polarisation component, which is perpendicular to the plane spanned by the spin
of the decaying neutron and the electron momentum, would prove a violation of
time reversal symmetry and thus physics beyond the Standard Model. The planned
accuracy of the measurement is of order 0.005. To reach this value, the
systematic effects in the experiment have to be controlled on a similar level
of accuracy. The emphasis of this master's thesis is put on the search of
systematic effects by the means of dedicated Monte Carlo simulation, based on
extended GEANT4 package. Implementation details are discussed and the new added
features are tested. Finally, the beta decay asymmetry induced systematic
effect, resulting in false contribution to R-coefficient is recognised and
investigated.
