Studies of OTR Angular Distribution on CTF2

Optical Transition Radiation (OTR) is widely used in beam diagnostics. The most common application is the acquisition of the transverse and longitudinal beam profiles. Other beam parameters, like divergence and energy, can also be deduced from the angular distribution of the OTR emission ("Doughnut"). In order to investigate the possibilities and the limits offered by this technique we have performed a test on the 48MeV, 1nC electron beam of the CLIC Test Facility 2 (CTF2.). Beam divergences between 2 and 6mrad were measured with an accuracy of a few percent. A good agreement was also found between the energy measurements obtained with a classical spectrometer and the OTR based technique. We conclude by describing some possible applications of OTR based diagnostics for CLIC.