Plasma Photocathode Beam Brightness Transformer for Laser-Plasma Accelerators

Hybrid laser-plasma accelerator schemes are emerging as tools capable of producing high-energy electron beams as drivers for advanced light sources. However, drastic improvements in beam quality and shot-to-shot stability are needed to establish these schemes for widespread use. RadiaBeam Technologies, with UCLA and Univ. of Strathclyde, propose to achieve dramatic improvements in beam quality (emittance), control, and tunability by developing a modular beam brightness transformer stage in addition to laser-plasma accelerator sections. This module incorporates a two-species gas mixture and allows for independent control of beam generation and acceleration. The scheme will be tested in a proof-of-concept experiment at SLAC FACET. In Phase I we successfully completed necessary modeling to address key component development for the proof-of-concept experiment at SLAC FACET including wakefield accelerator optimization, ionization analysis, and beam dynamics studies using enhanced 3D simulation capabilities. In Phase II, we will, for the first time, demonstrate the beam brightness transformer concept and characterize the beam parameters in the proof-of-concept experiments at SLAC FACET. The work plan includes design and development of novel plasma cells and diagnostic equipment to enable the beam characterization. Commercial Applications and Other Benefits: The proposed concept, when coupled as a driver for a future light source, will produce highly monoergetic, ultra short x-rays that have applicability specifically in compact-footprint devices. Such devices are useful for medical imaging and standoff active interrogation of nuclear materials.