New scheme to produce aneutronic fusion reactions by laser-accelerated ions

Abstract

The development of high-intensity lasers has opened the field of nuclear reactions initiated by laser-accelerated particles. One possible application is the production of aneutronic fusion reactions for clean fusion energy production. We propose an innovative scheme based on the use of two targets and present the first results obtained with the ELFIE facility (at the LULI Laboratory) for the proton–boron-11 (p–11B) fusion reaction. A proton beam, accelerated by the Target Normal Sheat Acceleration mechanism using a short laser pulse (12 J, 350 fs, 1.056 µm, 1019 W cm−2), is sent onto a boron target to initiate fusion reactions. The number of reactions is measured with particle diagnostics such as CR39 track-detectors, active nuclear diagnostic, Thomson Parabola, magnetic spectrometer, and time-of-flight detectors that collect the fusion products: the α-particles. Our experiment shows promising results for this scheme. In the present paper, we discuss its principle and advantages compared with another scheme that uses a single target and heating mechanisms directly with photons to initiate the same p–11B fusion reaction.

Directional Track Selection Technique in CR39 SSNTD for lowyield reaction experiments

“…A hole on this plate, placed in correspondence of that on the thick Al, allowed protons to reach the solid B sample. The expected reaction is p+ 11 B ® 3a [5][6][7][8][9][10][11][12]. The side of the CR39 detector facing the B target was unfiltered and so directly exposed to the alpha particles, but also to the recoil protons from target, which represented a source of noise to the detector.…”

“…Under these conditions, tracks with diameter of about 20 µm are expected for alphas in the 2-4 MeV range generated by possible pB fusions [5][6][7][8][9][10][11][12]. After the etching, the samples were scanned with an automated procedure by a reflection microscope, and this led to reconstruct a square image of 20 mm side.…”

“…In particular, they are the key diagnostics in investigation of low-yield nuclear reactions, such as the neutron-less p-11 B reactions generated by laser-matter interaction [5][6][7][8][9][10][11][12]. There is a strong interest in their application, both for energy production and for determining the reaction crosssections at low energies for astrophysical studies.…”

α particle space distribution from fusion reactions in Boron irradiated by mono-energetic protons

“…Experiments were performed in various laser facilities [4][5][6]. With the ABC, laser focusing 100J on plastic targets doped with Boron, the number of α particles detected is very low and the response of detectors is often uncertain.…”

Aneutronic pB-Reaction in Magnetized Inertial Confined Plasma of Laser-Accelerated Particles

“…As compared to other aneutronic reactions, pB reaction has the largest cross section in the region of the main resonance, σ max ≈ 1 b (at the energy of the relative motion of the nuclei E rel ≈ 675 keV), which is nevertheless much smaller than the maximum cross section for the reaction of deuterium with tritium (6 b at E rel ≈ 60 keV). The initiation of the pB reaction in the plasma is experimentally studied with the use of laser methods of creation of a hightemperature plasma and a proton beam [1][2][3][4]. The maximum detected yield of α particles in the pB reaction was about 10 9 [3].…”