Experimental Test of Semiconductor Dechirper*

We report the observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 4 inch long rectangular waveguide loaded with two silicon bars 0.25 inch thick and 0.5 inch wide. Silicon being a semiconductor has a conductivity that allows it to drain the charge fast in case if some electrons get intercepted by the dechirper. At the same time the conductivity is low enough for the skin depth to be large (on the order of 1 cm) making the silicon loaded waveguide a slow wave structure supporting wakefields that dechirp the beam.