Ammonia borane-based targets for new developments in laser-driven proton boron fusion

Abstract

Nuclear fusion reactions involving protons and boron-11 nuclei are sparking increasing interest thanks to advancements in high-intensity, short-pulse laser technology. This type of reaction holds potential for a wide array of applications, from controlled nuclear fusion to radiobiology and cancer therapy. In line with this motivation, solid ammonia borane samples were developed as target material for proton-boron (pB) nuclear fusion. Following synthesis and shaping, these samples were tested for the first time in a laser-plasma pB fusion experiment. An investigation campaign focusing on surface chemical/physical analysis was carried out to characterize such samples in terms of composition of B and H, precursors of the pB fusion nuclear reaction, thus having a key impact on the yield of the generated nuclear products, i.e., alpha particles. A follow-up experiment used an 8 J, 800 fs laser pulse with an intensity of 2 × 1019 W cm−2 to irradiate the targets, generating ∼ 108 alpha particles per steradian. The alpha particle energy range (2–6 MeV) and normalized yield per laser energy of up to (6 × 107 J/sr) are comparable with the best previous alpha particle yields found in literature. These results pave the way for a yet unexplored category of pB fusion targets.