Speaker
Description
Ultra-intense and well collimated gamma and particle beams in the Mega-electronvolt range are of interest for many applications in fundamental research as well as medical and technical applications. For example, in inertial confinement fusion (ICF) and in general nuclear fusion research, diagnostic tools are needed which allows to investigate as well as control plasma processes. Laser induced bright and well collimated short pulse photon and particle radiation sources are capable for such applications.
We present an efficient approach for providing gamma and particle beams based on enhanced production of direct laser-accelerated (DLA) electrons in relativistic laser pulse interactions with a long-scale near critical density plasma at $10^{19}\:W/cm^2$ laser intensity. Our experiments on the interaction of relativistic laser pulses with pre-ionized polymer foam target systems at hundreds Terawatt scale lasers showed a greatly improved conversion of laser energy into energy of Mega-electronenvolts gamma and particle radiation [1-3]. Recent improved experiments have shown the generation of ultra-bright and well-collimated gamma beams with laser energy to gamma conversion efficiency of more than 2% above 10 MeV gamma energy. Furthermore, we could demonstrate the generation of an ultra-intense neutron source with more than $6\times10^{10}$ neutrons per shot with a record laser energy to neutrons conversion efficiency of 0.05%, already at moderate relativistic laser intensities $\left(10^{19}\:W/cm^{2};20\:J\right)$ and ps pulse duration.
Here, I will talk about our results on ultra-intense and bright laser driven radiation sources (especially gamma and neutron sources) provided in interactions of relativistic laser pulses with pre-ionized nanostructured polymer foams. In general nanostructured targets play an important role for providing enhanced particle and improved plasma condition for applications.
The presented results on DLA based laser driven radiation sources such as neutron and gamma beam generation were performed in experiments under the affiliations GSI (Darmstadt, Germany) and Goethe-University (Frankfurt/Main, Germany). The presentation of future concepts and applications of laser induced secondary sources is supported by Marvel Fusion (Munich, Germany).
[1] M. M. Günther et al., “Forward-looking insights in laser-generated ultra-intense gamma-ray and neutron sources for nuclear applications and science”, Nature Communications, 13, 170 (2022).
[2] O. N. Rosmej et al, “Bright betatron radiation from directlaser-accelerated electrons at moderate relativistic laser intensity”, Matter and Radiation at Extremes, 6, 048401 (2021).
[3] P. Tavana et al. “Ultra-high efficiency bremsstrahlung production in the interaction of direct laser-accelerated electrons with high-Z material”, Frontiers in Physics, 11, 1178967 (2023).
