High-repetition-rate, multi-MeV deuteron acceleration from converging heavy water microjets at laser intensities of 1021 W/cm2

TLDR

Deuteron beams from laser‑driven jets can produce fast neutrons comparable to D–D fusion, relevant for material damage research. The study demonstrates high‑repetition‑rate deuteron acceleration using a continuous liquid heavy‑water jet irradiated by the ALEPH laser. A 120‑TW, 1.2×10^21 W/cm² ALEPH laser irradiated a continuous heavy‑water jet at 0.5 Hz while a Thomson parabola spectrometer recorded deuteron spectra for 60 shots. The experiment achieved peak deuteron fluxes of 5×10^10 deuterons sr^–1 pulse^–1 (average 1.5×10^12 sr^–1 min^–1) with energies up to 4.4 MeV and shot‑to‑shot stability within 40–50 % of the maximum energy.

Abstract

We demonstrate high repetition-rate deuteron acceleration by irradiating a continuously flowing, ambient temperature liquid heavy water jet with the high-intensity ALEPH laser. The laser delivered up to 5.5 J (120 TW, 1.2 × 1021 W/cm2) laser energy on target at 0.5 Hz. A high repetition-rate Thomson parabola spectrometer measured the deuteron beam energy spectra on each shot for 60 sequential shots (two minutes). Peak fluxes of 5×1010 deuterons/sr/pulse, corresponding to an average flux of 1.5×1012 deuterons/sr/min, were demonstrated with deuteron energies reaching up to 4.4 MeV. High shot-to-shot stability is observed up to 40%–50% of the maximum deuteron energy. These deuteron beams are suited for fast neutron production through deuteron breakup in a converter yielding energies similar to deuteron–deuteron (D–D, 2.45 MeV) fusion reactions of importance for material damage studies.