Beam Dynamics in the LEBT for FRANZ

The two Low Energy Beam Transport (LEBT) sections of the accelerator-driven neutron source FRANZ* consist of four solenoids. The first section with two solenoids will match the 120 keV proton beam into a chopper system**. Downstream from the chopper system a second section with two more solenoids will match the beam into the acceptance of the following RFQ. The accelerator will be operated using either a 2 mA dc beam or a pulsed beam with intensities from 50 mA to 200 mA at 250 kHz repetition rate. The high intensity of these ion beams requires the consideration of space-charge effects. Particle simulations with varying parameter sets have been performed in order to determine the settings providing best transmission and beam quality. Loss profiles along the transport channel were computed to identify hotspots. Simulation results for best transmission at lowest emittance growth will be presented