Shot-to-shot comparison of the first Li-beam driven hohlraum experiments

摘要

Shot-to-shot comparison of the first Li-beam hohlraum experiments on PBFA II provides an opportunity to measure and determine the factors that the affect on-axis reproducibility of the Li ion beam. Both inner shell and thermal x-ray emission are used to estimate the relative beam power on target from shot to shot. The M- and L-shell Au x-ray yield measurements were made with an array of 11 filtered PIN detectors, and the thermal emission measurements were made with an array of three filtered bolometers. The analysis shows that the beam intensity on target varied by more than a factor of ten during the shot series. By correlating the results of the beam on target with other diagnostics and events, we have identified some potential causes for these variations. A slight difference in top-to-bottom timing appears critical in affecting relative peak power on target.