A Multi-ampere Heavy Ion Injector for Linear Induction Accelerators Using Periodic Electrostatic Focusing*

One of the key problems for the accelerator system for a heavy ion fusion (HIF) power plant is to provide a source of ions at the parameters, principally energy and intensity, that are well matched for the primary accelerator component. A promising candidate for the primary accelerator component is the linear induction accelerator (LIA). The LIA is well matched to the pellet requirements because it can accelerate very high intensity pulses of short ( < 1 ps) duration. The intensity in the LIA is only limited by the capability of the beam transport system and the capacity of the in-. jection system. Recent cost studies at LBL show that there may be some economic advantage in using multiple-charge ions. The space charge limited transport of a quadrupole system permits charge states of approximately four when the other considerations that have been previously defined1 are included. Thus, fo$3Ex$zple, it would be possible to inject a pulse of approximately 150 uC of U in a 3 ps pulse at 100 MeV. Such a pulse, while well matched to the LIA, is far from state-of-the-art for any existing injection system and even well beyond the practical limits of systems of conventional ion sources, low-6 linacs, accumulator rings, etc., that have been suggested for various HIF scenarios.