Ricerc@Sapienza

We report on the radiation studies performed at the CLEAR facility of CERN in the sub-THz range, exploiting picosecond ultrarelativistic electron bunches for the production of coherent radiation. The coherent radiation, produced by different mechanisms (in particular coherent transition radiation), has been fully characterized using different techniques and detectors. The main aim has been that to setup a new beam-based source of radiation in the mm-waves for external users, individuating the performances and the limitations.

We report on the study of shadowing of electromagnetic fields radiated in the Terahertz (THz) region from two consecutive sources of coherent diffraction and transition radiation. In these conditions, the formation length is predicted to be ≲100 m, and shadowing effects should result in an almost complete suppression of radiated fields within distances of the order of tens of centimeters. We experimentally measured that shadowing effects disappear for distances significantly shorter than those predicted.