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The scientific and technical advances continue to support novel discoveries by allowing scientists to acquire new insights into the structure and properties of matter using new tools and sources. Notably, neutrons are among the most valuable sources in providing such a capability. At the Institute of Laser Engineering, Osaka, the first steps are taken towards the development of a table-top laser-driven neutron source, capable of producing a wide range of energies with high brightness and temporal resolution. By employing a pure hydrogen moderator, maintained at cryogenic temperature, a cold neutron ($$\le 25\hbox { meV}$$ ≤ 25 meV ) flux of $$\sim 2\times 10^3\hbox { n/cm}^2$$ ∼ 2 × 10 3 n/cm 2 /pulse was measured at the proximity of the moderator exit surface. The beam duration of hundreds of ns to tens of $$\upmu \hbox {s}$$ μ s is evaluated for neutron energies ranging from 100s keV down to meV via Monte-Carlo techniques. Presently, with the upcoming J-EPoCH high repetition rate laser at Osaka University, a cold neutron flux in orders of $$\sim 1\times 10^{9}\hbox { n/cm}^2/\hbox {s}$$ ∼ 1 × 10 9 n/cm 2 / s is expected to be delivered at the moderator in a compact beamline.

The scientific and technical advances continue to support novel discoveries by allowing scientists to acquire new insights into the structure and properties of matter using new tools and sources. Notably, neutrons are among the most valuable sources in providing such a capability. At the Institute of Laser Engineering, Osaka, the first steps are taken towards the development of a table-top laser-driven neutron source, capable of producing a wide range of energies with high brightness and temporal resolution. By employing a pure hydrogen moderator, maintained at cryogenic temperature, a cold neutron ([Formula: see text]) flux of [Formula: see text]/pulse was measured at the proximity of the moderator exit surface. The beam duration of hundreds of ns to tens of [Formula: see text] is evaluated for neutron energies ranging from 100s keV down to meV via Monte-Carlo techniques. Presently, with the upcoming J-EPoCH high repetition rate laser at Osaka University, a cold neutron flux in orders of [Formula: see text] is expected to be delivered at the moderator in a compact beamline.

We demonstrate that $(n,2n)$ reactions are induced by a high-flux pulse of fast neutrons ($\ensuremath{\sim}{10}^{10}$ neutrons in $\ensuremath{\sim}1\phantom{\rule{0.16em}{0ex}}\mathrm{ns}$) provided from a laser-driven neutron source (LDNS). The maximum energy of the broadband neutrons reaches a few tens MeV. Several kinds of metal targets are exposed to the fast neutrons. As a result, unstable isotopes, such as $^{54}\mathrm{Mn}, ^{58}\mathrm{Co}, ^{175}\mathrm{Hf}$, and $^{196}\mathrm{Au}$ are produced by $(n,2n)$ reactions and $^{180}\mathrm{Hf}^{m}, ^{181}\mathrm{Hf}, ^{56}\mathrm{Mn}, ^{198}\mathrm{Au}$, and $^{60}\mathrm{Co}$ are produced by $(n,\ensuremath{\gamma})$ reactions. We evaluate the neutron fluence and energy spectrum using the activation method in conjunction with a time-of-flight measurement. The neutron fluence is determined to be $(4.3\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{8}\phantom{\rule{0.16em}{0ex}}\mathrm{neutrons}/\mathrm{c}{\mathrm{m}}^{2}$ in the energy range from approximately 8 to 20 MeV at 8-mm downstream of the neutron source. The present scheme provides a method to evaluate high-density neutrons seen in stellar environments, which are expected to be generated from future LDNSs.

Study of warm dense matter remains a very important task for understanding of many unique phenomena observing as in astrophysical research as in inertial fusion and fast ignition. In this work, we studied the parameters of plasma created by 1.7 ps laser pulses of relativistic intensity of 7 × 1018W/cm2in a specially designed Al–Cu wire-shape target, in comparison with a flat Cu and Al foil targets. We observed the strong emission of neutral or virtually neutral CuKαline from both Cu foil and Cu wire part of targets, which indicates the creation of a dense state exposed to the intense flow of hot electrons. Parameters of the plasma were evaluated by comparison of experimental spectra with the results of modeling by collisional-radiative kinetic code PrismSpec under the plasma zone approach. The using of Al foil in front of Cu wire part of target allowed avoiding the direct heating of Cu-wire and acquiring spectra of Cu K-shell emission evidently belonging to emission of warm dense matter (WDM) state. The upper estimate for the electron temperature in WDM region was found to be below 80 eV.

Laser-driven ion acceleration attracts large attention due to variety of applications. In order to enhance accelerated proton energy and flux, we investigate the influence of laser-driven relativistic magnetic reconnection on the ion acceleration processes. In this relativistic regime, the longitudinal electric field becomes significantly enhanced and plays an important role in charged particle acceleration. To realize conditions for the magnetic reconnection, two spatially separated relativistic laser beams were used. The results obtained show a shift of high energy proton propagation direction compare to that corresponding to the target normal sheath acceleration scenario as well as enhancement in proton flux.

In order to enhance the conversion efficiency of ultra-intense laser energy into plasma leading to ion acceleration, we have performed an experiment with over-picosecond laser pulses having a relativistic intensity interacting with foam targets. We adjust the prepulse of the laser to control the plasma density near the critical density. The combination of hydrodynamic and particle-in-cell simulations suggest that the region of high energy density is induced in the near-critical plasma, leading to enhance the proton energy up to 23 MeV with the laser intensity of 6 × 1018 W/cm2.