Laser-generated Ion Beams for Medical Applications

The advent of high-power laser systems paved the way for laser acceleration of ion beams. Based on theoretical simulations, we demonstrate the feasibility of laser-generated ion beams matching the strict requirements for radio-oncological applications. Particle energies of several hundred MeV and low energy spreads of 1% are feasible within the framework of direct laser acceleration. A mechanism is suggested to efficiently post-accelerate particle beams originating from laser-plasma interaction processes, where the injection of ions into the focus is modeled in a realistic way. Introducing a long-wavelength CO₂ laser leads to an increase in the total number of particles accelerated as one bunch by three orders of magnitude as compared to lasers with a wavelength around 1 μm. By employing pulsed laser systems in a single- and a crossed-beams configuration, we show that ion beams of high particle numbers can be produced. In a different setting we put forward the interaction of a chirped laser pulse with a hydrogen gas target of spatial extension of the order of the laser wavelength studied by means of particle-in-cell simulations. The low frequency components of the laser pulse allow for generating clinically applicable beams already while interacting with state-of-the-art laser systems of intensities of 10²¹ W/cm<sup>2