Lawrence Berkeley National Laboratory

We report on the design and development of a strongly HOM damped copper RF cavity for the NLC damping rings. The cavity is based on the sucessful PEP-II RF cavity but incorporates many simplifications and improvements. The cavity is designed for a frequency of 714 MHz, gap voltage of 500 kV and beam current of 800 mA. We present the RF design and HOM impedance calculations done in MAFIA, the RF, thermal and stress analyses performed in ANSYS and the simplified mechanical design and assembly process. Designs for the RF window, HOM loads and tuners are described. Options for increasing the stored energy or further lowering the HOM impedance are discussed. This design could easily be scaled up or down in frequency and could be useful for other projects such as new light sources.