Preparation Status of the HIPPI Experiments

Introduction In order to meet the FAIR requirements for the acceleration of heavy ions (15 emA U, 5 emA U) a further improvement of the UNILAC performance is necessary. Therefore the correlation between space charge forces and focusing during acceleration of high intensity ion beams have to be understood in detail. The brilliance, i. e. ratio of beam current and beam emittance, is a suited quantity to study this correlation. It has to be determined and optimised for different phase advances σ0 of the Alvarez–quadrupoles which can be achieved by the variation of their field strengths. Therefore an 40Ar beam is used, as the required field strengths of these quadrupole lenses for equivalent measurements with U cannot be reached yet. Regarding space charge beam transport of 6 emA (40Ar) corresponds to that of 12.8 emA (U). In order to enable the acceleration of U with optimised brilliance the replacement of all Alvarez– quadrupole power supplies is hence part of the UNILAC upgrade program for FAIR. Within the beam dynamics working package of the European network ” High Intensity Pulsed Proton Injector” (HIPPI) investigations of space charge forces are funded. Benchmarking calculations for different codes are performed with respect to the treatment of space charge forces on the theoretical side [1]. Experimentally the beam brilliance along the UNILAC will be investigated and optimised in all three dimensions for high beam currents. A schematic overview of the experimental setup for the planned measurements is shown in Figure 1. Due to beam destructive emittance measurements no parasitic beam delivery through the UNILAC will be possible. For the first time exclusive beam time (96 shifts) for UNILAC machine experiments was requested and approved for 2006.