This paper describes the design and c onstruction of the axially insulated largearea diodes used in the 揌eaven1 ? The four axially insulated largearea diodes are connected to the 10 ohm pu lse transmission lines via the vacuum feed through tubes. The experimental resul ts with the diodes are given. The diodes can steadily work at the voltage of 650 kV, and the diode current density is about 80 A per cm2 with a pulse width of 220 ns.The electron beams with a total energy of 25 kJ are obtained.