Active neutron interrogation experiments and simulation verification using the SIngle-scintillator Neutron and Gamma-Ray spectrometer (SINGR) for geosciences - Heffern, Lena; Hardgrove, Craig; Parsons, Ann; Johnson, E.; Starr, R.; Stoddard, G.; Blakeley, R.; Prettyman, Thomas; Gabriel, Travis; Barnaby, H.; Christian, J.; Unzueta, M.A.; et al. (Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021)