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Highly charged energetic ions generated by the high intensity short pulse laser interaction with the solid density targets attracts many fields of applications including next generation ion accelerators. Although extensive attempts have been carried out in around the world to produce better quality beams in a controllable manner in the past decades, there are still issues to be improved before realising many the applications. We have been investigating the ion acceleration performance from the irradiation of sub-micron solid density plastic and metal folis foils by using two different petawatt-class laser systems, J-KAREN-P at KPSI and Draco at HZDR, aiming at the optimizing ion acceleration performance in a controllable manner. We have achieved generated the energetic light ion acceleration (> 50MeV proton and > 30 MeV/u C6+) and the highly charged energetic heavy ions (Ag and Au) acceleration by controlling the laser temporal pulse condition. Hydrodynamic and 3D particle-in-cell simulation reveals that the laser temporal pulse shape plays an a vital role on in making tailored density conditions for the main pulse for theto undergo relativistic transparency, which as a result forms a transient space-charge field for the efficient ion accelerations. The robustness of the acceleration mechanism is confirmed by the similar ion acceleration performance achieved in the two laser systems. The results pave the way for the establishment of repetitive laser driven ion sources with high energy and high peak current applicable to radiobiology and material science., 光・量子ビーム科学合同シンポジウム2022

Highly charged energetic ions generated by the high intensity short pulse laser interaction with the solid density targets attracts many fields of applications including next generation ion accelerators. Although extensive attempts have been carried out in around the world to produce better quality beams in a controllable manner in the past decades, there are still issues to be improved before realising many the applications. We have been investigating the ion acceleration performance from the irradiation of sub-micron solid density plastic and metal folis foils by using two different petawatt-class laser systems, J-KAREN-P at KPSI and Draco at HZDR, aiming at the optimizing ion acceleration performance in a controllable manner. We have achieved generated the energetic light ion acceleration (> 50MeV proton and > 30 MeV/u C6+) and the highly charged energetic heavy ions (Ag and Au) acceleration by controlling the laser temporal pulse condition. Hydrodynamic and 3D particle-in-cell simulation reveals that the laser temporal pulse shape plays an a vital role on in making tailored density conditions for the main pulse for theto undergo relativistic transparency, which as a result forms a transient space-charge field for the efficient ion accelerations. The robustness of the acceleration mechanism is confirmed by the similar ion acceleration performance achieved in the two laser systems. The results pave the way for the establishment of repetitive laser driven ion sources with high energy and high peak current applicable to radiobiology and material science., International conference on high energy density sciences 2022

Laser-driven ion acceleration promises to provide a compact solution for demanding applications like radio-biology experiments. For that, controlling particle beam parameters particularly in experiments with high energy Petawatt class ultra-short pulse systems with high repetition rate is a mandatory, yet challenging task. The performance of the plasma acceleration is strongly dependent on the complex laser target interaction which in turn is determined by the temporal laser intensity profile and spatio-temporal couplings on a large dynamic range. Plasma mirror setups have proven to significantly improve the temporal contrast by reducing pre-pulse intensity and steepening the rising edge of the main laser pulse, enabling the investigation of laser proton acceleration using ultra-thin and near critical density targets. Here we present benchmark experiments using the DRACO Petawatt laser at HZDR irradiating ultra-thin foil targets. A combination of particle and plasma diagnostics for ions and electrons as well as reflected and transmitted light revealed clear indications of acceleration in the relativistic transparency regime. The experiments were complemented by a suite of different laser pulse diagnostics, including self-referenced spectral interferometry with extended time excursion for single shot contrast analysis to characterize the laser pulse properties at the high power focus as realistic as possible.

We report on high pulse contrast operation modes of the Draco laser with focus on the on-shot characterization of the few-ps-contrast by novel techniques based on tilted beam self-referenced spectral interferometry with 108 dynamic range.