Modeling of a High Current H⁻ LEBT with the Lorentz‐EM 3D Ion Optics Code

High current electrostatic Low‐Energy Beam Transport (LEBT) systems are currently being developed for several applications ranging from H⁻ cyclotrons to high intensity linear accelerators. A new design building on the experiences gained from the Spallation Neutron Source (SNS) LEBT system was modeled recently in 2D with PBGUNS. In this paper a 3D treatment is given for this new LEBT design for a 60 mA, 65 kV H⁻ beam. For this type of LEBT 3D modeling is essential to accurately model the deflection of the co‐extracted electrons from the beam. The beam chopping and steering for RFQ injection also presents a 3D problem for the otherwise cylindrically symmetric geometry. The modeled LEBT can transport a 60 mA H⁻ beam with 0.2 π mm mrad 1‐rms emittance and Twiss parameters that are in accordance with established SNS LEBT specifications.