High Order Mode Damping in the NSLS Accelerating RF Cavities by the Use of Damping Antennae

High order modes have been successfully damped in the existing NSLS accelerating cavities by the insertion of damping antennae. The location of the antennae was aided by cavity field plots using superfish and their lengths determined experimentally. A description of their construction is presented together with the results of their insertion upon higher order cavity modes and beam stability.