Unidimensional neutron shielding model for VARSKIN+

A simple, one-dimensional neutron shielding model that can account for energy loss of neutrons traversing various materials (currently water and polyethylene, with a general framework for easy expansion to other materials) is developed and validated for use in the multipurpose dose calculation code VARSKIN+. Verification of this model is performed using Monte Carlo methods to provide an energy response comparison, and directly using empirically derived dose response curves for water shielding and a more realistic scenario of a source in a paraffin-filled barrel. Doses calculated using VARSKIN+ are within 20%-100% of the rigorous results, depending on complexity, and can be calculated within minutes, as opposed to hours for Monte Carlo results. This provides a good starting point for neutron shielding studies, before more computationally intensive tools are employed to calculate a more accurate dose value.