Measurement of Resistivity Dominated Collimator Wakefield Kicks at the Slc

Collimation of the multi-MW beams in present linear collider designs is a critical issue. Graphite as a possible collimator material exhibits good mechanical properties but a rather poor electrical conductivity. The resulting resistive wakefields can potentially deteriorate the beam quality. The knowledge of strength and scalings of such wakefields is essential for the design of the collimation systems in linear colliders. We present measurements of the self induced wakefield kick that a charged particle beam experiences when it passes through a narrow gap of two graphite collimator jaws. The measurements where performed with the highly damped SLC beam at an energy of 1.19 GeV. The results are compared to theoretical predictions and to measurements with copper collimators of the same shape.