Simulationen zur H- Charge Exchange Injection in den CERN Proton Synchrotron Booster mit Linac4

The CERN Proton Synchrotron Booster (PSB) is the first synchrotron of the LHC proton injection chain. The main limitation of the Booster performance is given by direct space charge effects at low energy. Linac2, the present pre-accelerator of the Booster, will be replaced by Linac4 in 2015. The main motivation for Linac4 is to increase the injection energy into the Booster from 50 MeV at present to 160 MeV to mitigate direct space charge effects. In addition, the conventional multiturn injection will be replaced by an H􀀀 charge exchange injection requiring special hardware and, in particular, a closed orbit bump in the injection section (chicane) introducing perturbations on the lattice. Two different schemes which aim at mitigating the impact of these perturbations on PSB performance were tested: an active compensation with additional quadrupole components at dedicated positions in the ring and a passive compensation with gradients added to the chicane magnets. To find the best setting for the injection, simulations with the particle tracking code ORBIT were carried out for both schemes and the different results were compared. The simulations include the apertures, acceleration, space charge effects, scattering at the injection foil and planned schemes to populate the available phase space in transverse and longitudinal plane (Painting).