A newly developed gamma-ray computed tomography scanner was implemented to study liquid flow distribution in a 30.48-cm-diameter column packed with corrugated structure using countercurrent air-water flow. Validation experiments confirm that spatial resolution of similar to2.5 mm can be achieved by the new CT unit. Within the gas (0-10 cm/s superficial velocity) and liquid (0.6-2.5 cm/s superficial velocity) flow ranges investigated, a good liquid distribution was observed at all conditions, as manifested by uniformity factor in excess of 70%. The liquid saturation increases with increasing superficial liquid velocity, as well as down the column height. Within the conditions studied, the effect of gas velocity was, in general, found to be minimal. (C) 2004 Elsevier B.V. All rights reserved.