Using the plasma-focus device called PACO (Plasma Auto COnfinado), three types of cathodes were experimentally investigated to evaluate their influence on the hard x-ray production. Two barred cathodes with diameters of 82 mm and 90 mm and one cathode without any specific structure (i.e. the current sheet flowed freely on the radial axis) were tested for this work. In every experiment, the capacitor bank was charged to 31 kV. The gas used was deuterium in the pressure range of 0.5 mbar and 3.0 mbar. The production of neutrons and hard x-ray simultaneously was not detected outside this range. Using the cathode with a diameter of 82 mm the hard x-ray production was maximized.