Beam Optics Effects at the entrance of SARAF RFQ

A strong effect of the 176 MHz RF field on the low energy beam optics was observed at the SARAF RFQ/LEBT interface. The effect was studied for various LEBT proton beam energies and for the broad range of RE field amplitudes. The measurements and simulations suggest that, most likely, the effect is associated with loss of the beam neutralization in the LEBT region adjacent to RFQ due to penetration of the field in this region. The effect is partially responsible for reduction in the RFQ injector transmission.