Innovations in Laser-Driven pB Fusion Research at ELI Beamlines and Charles University

High-intensity laser pulses interacting with materials rich in hydrogen and boron, when properly configured, can initiate the proton-boron (pB) fusion reaction, resulting in the generation of three energetic alpha particles (p+11B → 3He + 8.7 MeV). These alpha particles are of considerable interest in emerging applications such as green energy production and non-invasive cancer treatments.

One potential approach to increasing alpha particle yield is to explore various target configurations, modifying the concentrations of the elements involved in the reaction or enhancing laser absorption by the target. In our study, we first conducted an experiment aimed at boosting the volumetric laser absorption within the target by using boron nitride nanotube (BNNT) targets, which possess an average density of 1/5th that of solid density and compared the results with a standard flat Polyester (PS) target [1]. The comparison showed a 1.5-fold increase in proton cutoff energy and a 2.5-fold increase in the N4+ / C4+ ion cutoff energy. Additionally, we employed thin films of plasma polymers ppC:H evaporated on BN substrates with varying densities. These ppC:H films were used as hydrogen sources when their properties were optimally matched with the laser parameters [2-3]. Currently, to combine the benefits of target morphology and low density with the hydrogen content of the target, we have prepared plasma polymerized hexane nanoparticles (ppC:H NPs) within a gas aggregation cluster source (GAS) as advanced targets for laser-driven pB fusion. These targets have successfully triggered the pB fusion reaction using a short pulse high energy laser TARANIS (8J in 900fs) and the results showed that ppC:H NPs combined with B-rich materials enhance the laser-driven pB fusion.

1. M. Tosca, A. Morace et al., Physical Review Research (2024) DOI 10.1103/PhysRevResearch.6.023326

2. V. Istokskaia, M. Tosca et al., Communications Physics 6 (2023), 10.1038/s42005-023-01135-x.

3. M. Tosca, D. P. Molloy et al., Frontiers of physics (2023) DOI 10.3389/fphy.2023.1227140.