Including Internal Losses in the Equivalent Circuit Model of the Slac Damped Detuned Structure (dds)

In the equivalent circuit model for the DDS originally presented no losses were explicitly included in the cell circuits or the manifold circuits. Damping via the manifolds was effected by imposing matching conditions (including the possibility of reflection) on the ends of the manifolds. In this paper we extend the circuit theory to include lossy circuit elements. We discuss and compare shunt conductance and series resistance models for the cells. Manifold damping is modeled by introducing a shunt conductance per unit length in the transmission line elements of the manifolds. We apply the theory to the mitigation of performance degradation associated with fabricationally desirable decoupling of several cells at the ends of the structure from the manifolds. Paper presented at the 1999 Particle Accelerator Conference (PAC99) New York City, New York, USA March 29-April 2, 1999 This work is supported by Department of Energy grant numbers DE-AC03-76SF00515 and DE-FG03-93ER40759 .