Preliminary Experimentation of Fast Neutron Radiography with D-T Neutron Generator at BARC

Abstract

An experimental study on fast neutron radiography (FNR) has been carried out using a laboratory based D-T neutron generator facility at Bhabha Atomic Research Centre (BARC) and initial results are presented. The aim was to develop an FNR system with a moderate intensity neutron source for imaging of specimen containing mixed low-Z and high-Z materials. The experimental set-up consists of a D-T neutron generator, collimator and an EMCCD camera based imaging system. Experiments were carried out with the neutron generator having a source strength of about 2 × 109 n/s and source spot size of 20 mm. To obtain optimum image quality with such a moderate neutron yield, a collimator has been designed having an inlet aperture of 10 mm and an L/D of 43. The imaging system was kept at an optimum distance from the collimator and various test samples of materials ranging from low Z to high Z were imaged. Thick samples in step wedge form, hole features in step wedge of polyethylene, mild steel and lead were imaged and analysed. Also a test sample of a low Z material (HDPE) with a hole placed behind a thick Pb was imaged to study the effect of thickness of high Z material on image quality with fast neutrons. The initial results emphasizes that a moderate yield D-T neutron generator based fast neutron radiography system with EMCCD camera could be deployed for field applications yielding moderate image quality to obtain first hand information of the investigated samples.