  The ridgetron is used to accelerate the intense beam for the electron
irradiation. According to the electromagnetic field simulation, the extend
electrode should be cancelled to increase the shunt impedence. The method of
parameter sweeping with constraint variables (PSCV) is used to scan the
mechanical parameters of the cavity to optimize the shunt impedence. The
thermal analysis also has been done for water cooling. The beam dynamic
simulation has been done at last.
