Speaker: Jeffrey Alan Powell, Institut National de la Recherché Scientifique (INRS-EMT)
Program Description:
Laser-based, tabletop electron acceleration is an active research area which can provide a compact alternative to traditional sources. The ultrafast nature of the laser-matter interaction produces ultrashort electron bunches that are useful for dynamic imaging experiments in atoms and molecules as well as ultra-high dose rate radiobiological studies. Through a process called longitudinal electron acceleration (LEA), our team has recently used a mJ-class IR laser to generate electron energies up to 1.2 MeV and has uncovered an intricate dependency on the gas species used. Theoretical analysis confirms that atom-specific, sub-cycle ionization dynamics dictate the time of injection of the photoelectron into the laser field and the subsequent maximum energy gain. Furthermore, we discovered we can reach relativistic intensities (>1018 W/cm2) in ambient air in this same configuration, producing a very high dose-rate source of MeV electrons (arXiv:2207.05773), potentially useful for oncology applications such as FLASH-RT.
