Laser-induced acceleration of Helium ions from unpolarized gas jets

• Published in: Plasma physics and controlled fusion 2019-11, Vol.61 (11), p.115012
• Main Authors: Engin, Ilhan, Chitgar, Zahra M, Deppert, Oliver, Lucchio, Laura Di, Engels, Ralf, Fedorets, Pavel, Frydrych, Simon, Gibbon, Paul, Kleinschmidt, Annika, Lehrach, Andreas, Maier, Rudolf, Prasuhn, Dieter, Roth, Markus, Schlüter, Friederike, Schneider, Claus M, Stöhlker, Thomas, Strathmann, Katharina, Büscher, Markus
• Format: Article
• Language: English
• Subjects: laser-driven He-ion acceleration; polarized nuclear fusion; spin-polarized ion source
• ISSN: 0741-3335; 1361-6587
• DOI: 10.1088/1361-6587/ab4613

In order to develop a laser-driven spin-polarized 3He-ion beam source available for nuclear-physics experiments as well as for the investigation of polarized nuclear fusion, several challenges have to be overcome. Apart from the provision of a properly polarized 3He gas-jet target, one of the biggest milestones is the demonstration of the general feasibility of laser-induced ion acceleration out of gas-jet targets. Of particular importance is the knowledge about the main ion-emission angles as well as the achievable ion-energy spectra (dependent on the optimal set of laser and target parameters). We report on the results of such a feasibility study performed at PHELIX, GSI Darmstadt. Both 3He- and 4He-gas jets (ngas ∼ 1019 cm−3) were illuminated with high-intensity laser pulses, I L ∼  ( 10 19 W cm − 2 ) . The main ion-emission angles could be identified ( 90° with respect to the laser-propagation direction) and the ion-energy spectra for all ion species could be extracted: for the optimal laser and target parameters, the high-energy cut-offs for He 2 + , 1 + ions were 4.65 MeV (with a normalized energy uncertainty of Δ   − 1 = 0.033 ) and 3.27 MeV ( Δ   − 1 = 0.055 ), respectively.