Measurements of triple differential cross section for double ionization in atomic calicum. A. De Fanis, K.J. Ross, H.-J. Beyer and J.B. West Department of Physics, Southampton University, Southampton, UK The triple differential cross section for 4s double photoionization in atomic calcium has been measured in the region of the giant 3p-3d resonance. Electrons are detected in coincidence in the plane perpendicular to the photon beam. Results are compared with previous ab-initio calculation and with similar results with the He atoms.