Measurement of proton, lithium, and fluorine ion energy densities on PBFA II

In the light-ion-beam fusion program at Sandia National Laboratories an intense lithium beam is being developed to drive inertial confinement fusion targets. An important parameter of this lithium beam is its purity. To reduce potential contamination of the lithium beam by protons, carbon, and oxygen significant improvements to the vacuum system of the Particle Beam Fusion Accelerator II (PBFA II) have been made and in-situ methods of cleaning the anode ion source have been introduced. To help assess the effectiveness of these improvements on reducing the impurities in the lithium beam the authors have developed and fielded new, nuclear activation diagnostics for measuring the individual energy densities of lithium, protons, and fluorine in the beam. Using these diagnostics they have measured the energy densities of lithium, protons, and fluorine at each pepper shaker location. These data give an indication of both the uniformity of the beam and the fraction of proton and fluorine impurities in the lithium beam. The results of these measurements are presented