Fast neutron tomography with real-time pulse-shape discrimination in organic scintillation detectors

A fast neutron tomography system based on the use of real-time pulse-shape discrimination hi 7 organic liquid scintillation detectors is described. The system has been tested with a californium-252 source of dose rate 163 mu Sv/h at 1 m and neutron emission rate of 1.5 x 10(7) per second into 4 pi and a maximum acquisition time of 2 h, to characterize two 100 x 100 x 100 mm(3) concrete samples. The first of these was a solid sample and the second has a vertical, cylindrical void. The experimental data, supported by simulations with both Monte Carlo methods and MATLAB (R), indicate that the presence of the internal cylindrical void, corners and inhomogeneities in the samples can be discerned. The potential for fast neutron assay of this type with the capability to probe hydrogenous features in large low-Z samples is discussed. Neutron tomography of bulk porous samples is achieved that combines effective penetration not possible with thermal neutrons in the absence of beam hardening. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.