Particle Physics Seminar: Undepleted Direct Laser Acceleration
Itamar Cohen, TAU
Intense lasers made available for the first-time high energy electron sources at university scale laboratories. For the past two decades, the community focused on optimizing the accelerated beam quality in terms of higher energy, sharper energy spectrum, and improved repeatability. A few early works identified one acceleration technique in which a solid foil is pre-exploded and expands into a plasma plume. The interaction of the main laser with the plume generates ultra-collimated, multi-MeV beams of electrons by direct laser acceleration (DLA) method.
With DLA, the leading part of the laser pulse ionizes the target material and forms a positively charged ion plasma channel into which electrons are injected and accelerated. The high energy conversion efficiency of DLA makes it ideal for generating large numbers of photo-nuclear reactions. I will present results from an experimental investigation of the DLA in a new parameter space by controlling the pre-plasma profile and the ion content available for ionization .
The pre-plasma is modeled with a new analytical model for the expansion of a thin slab of plasma into vacuum . We demonstrate experimentally and numerically that when the atomic number is too low, the target is depleted of its ionization electrons prematurely.
We present an experimental characterization of the emitted beams in terms of energy, charge, divergence, and repeatability, and several examples of prospective applications for industry and research. Furthermore, we demonstrated repeated generation of photoneutrons. The neutrons are generated in a secondary metal target placed downstream of the electron beam.
Seminar Organizer: Dr. Michael Geller