Laser-Driven Ion Acceleration from Cryogenic Liquid Argon Jets Using a PW Laser

Efficient generation of high-Z ion beams is critical for advancing applications in high energy density physics, cancer therapy, nuclear science, and material research toward inertial fusion energy (IFE). However, laser-driven acceleration of heavy ion beams from solid-density targets is typically limited by surface contaminants that favor light-ion emission. Cryogenic liquid jets overcome this limitation by providing pure, tunable thickness targets. Furthermore, these targets are continuously refreshing and debris-free, ideal for high-repetition-rate (HRR) operation. In a recent experiment at HZDR, cylindrical cryogenic argon jets (5 and 10 µm diameters) were irradiated by the DRACO petawatt laser (800 nm, 20 J, 30 fs) at intensities up to 5e21W/cm². Ion beam spectra and angular distributions were characterized using Thomson parabola spectrometers with MCPs and time-of-flight detectors. Argon beams reach a nearly fully ionized state with kinetic energies exceeding 500 MeV and laser-to-ion beam energy conversion efficiencies of ~2%. These results are compared with previous experimental data and simulations. These results demonstrate the suitability of cryogenic jets for efficient generation of high-energy heavy ion beams and establish them as a promising platform for future beam-target interaction experiments to study the material response and nuclear reactions.

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