Monte Carlo design of a moderator to produce a thermal neutron source from a 241Am/9Be source

The main tasks developed in the work were to evaluate the geometry of moderator and to select the neutron source position, to optimize the thermal neutrons flux in the area where the sample to analyze must be placed and estimate the dose rate. This configuration can be employed hereafter in detection of trace in substances or materials, through the NAA (Neutron Activation Analysis) method.