Abstract
Void fraction of air-water two phase flow has been investigated using neutron backscatter imaging technique. A series of static measurements have been carried out for pipes having different radii and wall thicknesses. The obtained thermal neutron images successfully discriminate between the pipes having different void fraction. Linear-relationship describes the values of backscattered thermal neutrons obtained from the reconstructed images and void fraction with some deviations in case of pipe four when buried at 10 cm depth. The obtained results indicate the reliability and effectiveness of the technique for studying void fraction of air-water two phase flow.