Coherent Synchrotron Radiation Measurements in the CLIC Test Facility (CTF II)

Bunches of high charge (up to 10 nC) are compressed in length in the CTF IImagnetic chicane to less than 0.2 mm rms. The short bunches radiate coherentlyin the chicane magnetic field, and the horizontal and longitudinal phase spacedensity distributions are affected. This paper reports the results of beamemittance and momentum measurements. Horizontal and vertical emittances andmomentum spectra were measured for different bunch compression factors andbunch charges. In particular, for 10 nC bunches, the mean beam momentumdecreased by about 5% while the FWHM momentum spread increased from 5% to 19%.The experimental results are compared with simulations made with the codeTraFiC4.