Control of tunable, quasi-monoenergetic electron beams from laser-plasma accelerators and their application for compact, narrow bandwidth Thomson photon sources*

We demonstrate precise control of a laser-plasma accelerator (LPA) using a shock-induced density down-ramp injector. Experiments systematically varied the shock injector profile, including the shock angle, up-ramp width, and acceleration length. These results establish that, by adjusting shock position, up-ramp, and angle, beam energy, energy spread, and pointing can be controlled. As a result, e-beam were highly tunable from 30 to 300 MeV with <10% energy spread, 1.5 mrad divergence and 0.35 mrad pointing fluctuation. Particle-in-cell (PIC) simulation characterized how variations in the shock profile impacted the injection process. This highly controllable LPA represents a suitable and compact beam source for the MeV Thomson photon experiments now being started on a newly constructed one hundred TW laser system. Set-up and initial experiments using this system will be presented.