MEASUREMENTS AND SIMULATIONS ON THE BEAM BRILLIANCE IN THE UNIVERSAL LINEAR ACCELERATOR UNILAC AT GSI

In the framework of the GSI beam intensity upgrade program for the heavy ion synchrotron (SIS) the UNILAC was upgraded to deliver intense heavy ion beams up to uranium under space charge conditions. The SIS has to be filled up to its space charge limit. Measurements and simulations on the transverse beam emittance growth during acceleration in the Alvarez section of the UNILAC were performed. Transverse beam emittances were measured before and after the Alvarez section using a pepper pot and the slit-grid method. Results of measurements on the decrease of the beam brilliance of an intense Ar 10+ beam (10 emA) during acceleration are presented. The space charge forces correspond to an U 28+ beam with an intensity of 21 emA (design current 12.6 emA). Simulations on the dynamics of an high intense beam during acceleration were done using the code PARMILA. The experimental and theoretical results are discussed.