Fast neutron radiography and tomography at a 10Â MW research reactor beamline

Fast neutron imaging was performed using a beamline of the 10 MW research reactor of the Budapest Neutron Centre, Hungary. A simple, low-cost 2D area detector has been used featuring a 8 mm thick BC400 plastic scintillator converter screen and a CCD camera. A spatial resolution of around 1.3mm has been achieved. Typically 10 min long exposures were needed to obtain reasonable quality radiographic images. For tomographic imaging typically several hours of acquisition were needed to obtain reasonable quality on non-symmetric and larger (e.g. 10×10×10cm3) objects. Due to the presence of a significant gamma background at the experimental position, massive (30 cm thick) lead shielding and filtering was applied to the beam. The gamma contribution was mostly baseline independent of the object imaged and therefore could be subtracted, whereas the direct gamma contribution from the beam to the imaging detector signal is estimated to be less than 1%.