Angular distribution of scattered neutrons as a tool for soil moisture measurement: A feasibility study

The conceptual design of a soil-moisture measurement instrument using a rectangular soil sample and an almost collimated ²⁴¹Am-⁹Be source was proposed. Unlike previous studies and in a different simulation approach, the soil moisture was determined using the angular distribution of thermal neutrons using MCNPX2.6 Monte Carlo code, where a cylindrical BF₃ proportional counter located at different polar angles was responsible for thermal neutron detection. Both Monte Carlo library least-squares method (MCLLS) and artificial neural networks (ANN) were used to calculate the soil moisture based on BF₃ count rates with small relative error, about 2% and 10% maximum relative errors, respectively.