Laser-Driven Neutron Generation with Near-Critical Targets and Application to Materials Characterization

Abstract

Laser-driven neutrons arouse outstanding interest because of their promising uses in several fields, from basic science to materials inspection. Many experiments achieved neutron yields [${10}^{8}\ensuremath{-}{10}^{10}\phantom{\rule{0.2em}{0ex}}\mathrm{n}/(\text{sr s})$] suitable for applications. These results were obtained by exploiting high-energy (approximately $10$--$100\phantom{\rule{0.2em}{0ex}}\mathrm{J}$) lasers working at low repetition rates. Instead, adopting advanced target configurations like near-critical double-layer targets (DLTs) and compact, commercial lasers was slightly considered. Here, a theoretical study is performed to address neutron generation with commercial ($40$--$400\phantom{\rule{0.2em}{0ex}}\mathrm{TW}$, $1$--$15\phantom{\rule{0.2em}{0ex}}\mathrm{J}$) systems and DLTs. We investigate proton acceleration and interaction with various materials to induce ($p,n$) reactions. DLTs allow achieving $1$--$2$ orders of magnitude larger neutron yields and maximum energies 3 times higher than with single-layer targets. Then, the feasibility of two materials characterization techniques, namely fast neutron activation analysis and pulsed fast neutron resonance radiography, is assessed. The results indicate that they can be performed with commercial lasers and DLTs.