Assessment of sensitivities and uncertainties in Monte Carlo particle transport calculations for neutron spectrometry

Monte Carlo particle transport (MCPT) calculations are increasingly used in neutron metrology and especially in neutron spectrometry for the numerical simulation of measurements based on computational models for the underlying experiment. Sensitivities express the dependence of results on input data and uncertainties are a measure of the dispersion of calculated or measured values. The knowledge of sensitivities is instrumental for physical understanding and a possible optimisation of computational models and/or the experiments. The assessment of uncertainties is necessary to state the degree of belief in results and to objectively validate calculations by measurements. Methods used in MCPT calculations which assess sensitivities of the computational model and propagate uncertainties associated with input data are discussed. The technique most often used is demonstrated by a simple example.