Optimisation of a neutron imaging system using the modulation transfer function

The use of the modulation transfer function was explored for the characterisation and optimisation of the optical system used for tomographic imaging on the DINGO instrument at the Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia. Both a Siemens star and a phantom were used to determine the modulation transfer function and the results are compared. This allowed the optimal configuration of the instrument to be determined and the establishment of a relationship between sample dimension, exposure time and radiograph resolution to be developed. For tomographic studies of large samples, best results were achieved with DINGO configured in high-flux mode (L/D = 500), with a 6LiF/ZnS scintillator screen, an Iris 15TM sCMOS detector, a 50 mm lens, and an exposure time between 4 and 8 s.