LLNL flash X-ray radiography machine (FXR) double-pulse upgrade diagnostics

When the FXR machine was first tuned on the 1980s, a minimal amount of diagnostics was available and consisted mostly of power monitors. During the accelerator upgrade, additional beam diagnostics were added. The sensor upgrades included beam bugs (resistive wall beam motion sensors) and high-frequency B-dot. Even with this suite of measurement tools, tuning was difficult. For the current double-pulse upgrade, beam transport is a more complex problem-the beam characteristics must be measured better. Streak and framing cameras, which measure beam size and motions, are being added. Characterization of the beam along the entire accelerator is expected and other techniques are also evaluated. Each sensor has limitations and only provides a piece of the puzzle. Besides providing more beam data, the set of diagnostics used should be broad enough so results can be cross validated. Results are also compared to theoretical calculations and computer models, and successes and difficulties are reported.