Progress in ion beam research at Sandia National Laboratories

Significant progress has been made recently in ion-beam production and focusing in both radial focusing and extraction geometries. Experiments on Sandia's Particle Beam Fusion Accelerator (PBFA) II have demonstrated efficient ion-beam generation, with 0.6 MJ of ions produced with 80% ion efficiency on experiments at the 3/4 energy level. With the flashover ion sources presently used on PBFA II, approximately half of the ion are protons. Horizontal FWHM proton focuses of approximately 5 mm have been obtained at diode voltages of over 5 MV. Experiments have revealed a linear scaling of FWHM with anode-cathode gap. Experiments and simulations have provided important information on the effects of both solenoidal and self-field focusing in the diode. Extraction diode experiments have been conducted in support of Sandia's light ion version of the US Department of Energy's Laboratory Microfusion Facility (LMF). Results from diode experiments on the 0.7-TW Mite accelerator together with an improved understanding of diode operation provide a reasonable path to a 30-MV, 1.2-MA LMF module.<>