  Cosmic-Ray Neutron Sensing (CRNS) is a novel technique for determining
environmental water content by measuring albedo neutrons in the epithermal to
fast energy range with moderated neutron detectors. We have investigated the
response function of stationary and mobile neutron detectors typically used for
environmental research in order to improve the model accuracy for neutron
transport studies. Monte Carlo simulations have been performed in order to
analyze the detection probability in terms of energy-dependent response and
angular sensitivity for different variants of CRNS detectors and converter
gases. Our results reveal the sensor's response to neutron energies from 0.1 eV
to 1 MeV and highest sensitivity to vertical fluxes. The detector efficiency
shows good agreement with reference data from the structurally similar Bonner
Spheres. The relative probability of neutrons contributing to the overall
integrated signal is especially important in regions with non-uniform albedo
fluxes, such as complex terrain or heterogeneous distribution of hydrogen
pools.
