Generation of quasi-monoenergetic ions using optimized hollow nanospheres

Abstract

For ultra-high-intensity lasers irradiating nanometer-sized targets, Coulomb explosion (CE) is one of the main ion acceleration schemes. Previous studies have shown that the CE of solid nanospheres can produce quasi-monoenergetic ions. However, the development of optimized hollow nanospheres has yet to be achieved. Currently, the technology for the production of various types of hollow nanospheres has already been established. Still, the applications of hollow nanospheres are more inclined toward energy storage. This study shows that CE-based ion acceleration is another plausible application for these hollow nanospheres. Different nanosphere designs were analyzed using simple analytical models, which showed the possibility of using them to produce quasi-monoenergetic ions. This was then confirmed using one-dimensional particle–particle simulations in spherical coordinates. Overall, the results showed that hollow nanospheres are viable targets that can be used for the production of quasi-monoenergetic ions via spherical CE. Furthermore, the new proposed target design substantially improved the energy coupling efficiency.

Application of encapsulated hollow gold nanocluster targets for high-quality and quasi-monoenergetic ions generation

“…Using the target designs introduced in figure 1, two-dimensional distribution of ions is shown in figure 2 at the end of interaction (224 T 0 ). As figure 2(a) shows, the interaction of LP pulse with a bare hollow nanosphere leads to almost a uniform quasispherical distribution of H + and C 6+ ions which is roughly in agreements with results in [38]. Since the cell size is 10 nm, we should see very pixelized particles during the ionization of the entire target, which may affect the round sphere.…”

“…Despite these differences, we observed that both encapsulated HNC and CVL targets can potentially reduce ions' divergence and optimize monoenergeticity. Therefore, not only one can consider them as an alternative to produce high-quality and quasi-monoenergetic ions beam, but the structures can be known as a complement to the hollow nanosphere targets proposed by Zosa and Murakami in [38].…”

“…In contrast, for a CE in heterogeneous cluster, the density ratio of the light species to the heavy particles must be approximately ∝1/3 to optimize the particles' maximum number and monoenergeticity. To further study, Zosa and Murakami proposed to use the hollow nanospheres to produce quasi-monoenergetic protons and C 6+ ions through CE acceleration method [38]. To support the benefits of using hollow nanospheres, they introduced the results of ions acceleration by using the two-dimensional particle-incell (PIC) simulation.…”

“…In order to fully utilize CE in laser-cluster ion acceleration, we require further simulation research to find out the optimized target design. Following the acceleration schemes in [36] and [38], in this paper, I study the acceleration of heavy and light ions by proposing the encapsulated hollow gold-nanocluster structure. The study of gold nanoclusters is of great importance in chemistry and material science [39][40][41].…”

100 MeV protons from nanostructured hemispherical target using PIC simulations

“…Experimentally, isolated micron-sized spherical targets have been found to generate quasi-monoenergetic proton and heavier ion energy spectra [16]. There has been a growing interest in hollow spherical targets, which are found to facilitate effective trapping of laser energy [17][18][19]. This capability has been harnessed not only for the study of ion acceleration but also for the exploration of neutron generation.…”