Experimental observation of IFEL micro-bunching using coherent transition radiation

Electron beam bunching in the optical wavelength was observed experimentally for the first time at the Brookhaven Accelerator Test Facility (ATF) using the inverse free electron (IFEL) accelerator. The micro-bunched electron beam has been studied by measuring the coherent transition radiation (CTR). We have experimentally observed a quadratic dependency of the CTR signal with the charge of the electron beam and the observation distance.