High Current Linear Ion Accelerators Utilizing Electron Neutralization

The transport and post-acceleration of multikiloampere ion beams is being studied at Sandia Laboratories for application to inertial fusion. A number of projects have been carried out over the past year, including theoretical investigation of non-linear beam transport, rapid space charge neutralization of ion beams by electrons emitted from boundaries, and longitudinal instabilities of pulseline driven linear accelerators. In the experimental part of the program, injectors have been developed which can deliver 10 kA of protons and 2 kA of carbon ions (at 100-200 keV) for microsecond pulse durations. These beams have been post-accelerated in a magnetically insulated acceleration gap. By suitably shaping the electrostatic gap boundaries, focusing of the beams has been demonstrated.