Optimization of the volume H− ion source extraction system for the Spallation Neutron Source accelerator utilizing 3D magnet and ion optics codes

The H− beam extraction from the multicusp ion source for the Spallation Neutron Source (SNS) is being simulated utilizing the 3D ion optics code KOBRA and the 3D magnet code TOSCA. Design of the extraction system for the SNS project requires proper simulation of the extraction of both electrons and H− ions. The goal is to optimize the magnetic field of the extraction system so that the electrons are completely deflected and captured at the plasma electrode.