LLNL, Livermore, California, USA
LLNL's compact, tunable, laser-Compton x-ray source has been built around an advanced X-band photogun and accelerator sections and two independent laser systems. In support of this source, the control system has evolved from a minimal, isolated control points to an integrated architecture that continues to grow to simplify operation of the system and to meet new needs of this research capability. In addition to a PLC-based machine protection component, a custom, LabView-based suite of control software monitors systems including low level and high power RF, vacuum, magnets, and beam imaging cameras. This system includes a comprehensive operator interface, automated arc detection and rf processing to optimize rf conditioning of the high-gradient structures, and automated quad-scan-based emittance measurements to explore the beam tuning parameter space. The latest upgrade to the system includes a switch from real-time OS to FPGA-based low-level RF generation and arc detection. This offloads processing effort from the main processor allowing for arbitrary expansion of the monitored points. It also allows the possibility of responding to arcs before the pulse is complete.
UCI, Irvine, California, USA
LLNL, Livermore, California, USA
30 keV Compton-scattered X-rays have been produced at LLNL. The flux, bandwidth, and X-ray source focal spot size have been characterized using an X-ray ICCD camera and results agree very well with modeling predictions. The RMS source size inferred from direct electron beam spot size measurement is 17 um , while imaging of the penumbra yields an upper bound of 42 um. The accuracy of the latter method is limited by the spatial resolution of the imaging system, which has been characterized as well, and is expected to improve after the upgrade of the X-ray camera later this year.
