As a part of the systematic research conducted to study the scaling of Plasma Focus experiments to small devices, radial dynamic and density measurements using Hydrogen and Deuterium as filling gas in the PF-50J device are presented. Results confirm that the expected dynamics observed in large experiments and densities of the order 1025 m-3 at the pinch time are present in our experiments operated at only 67J. © 2009 American Institute of Physics.