ABSTRACT
Laser-driven proton accelerators are relevant candidates for many applications such as material science or medicine. Today, there are multi-hundred-TW table-top laser systems that can generate relativistic peak intensities >1018 W/cm2 and routinely reach proton energies in the MeV range. However, for most desired applications, there is still a need to optimize the quality and stability of the laser-generated proton beam. In this work, we developed a 0.625 Hz high repetition-rate setup in which a laser with 2.5% RMS energy stability is irradiating a solid target with an intensity of 1019 to 1020 W/cm2 to explore proton energy and yield variations, both with high shot statistics (up to about 400 laser shots) and using different interaction targets. Investigating the above-mentioned parameters is important for applications that rely on specific parts of the proton spectrum or a high ion flux produced over quick multi-shot irradiation. We demonstrate that the use of a stable "multi-shot mode" allows improving applications, e.g., in the detection of trace elements using laser-driven particle-induced x-ray emission.
ABSTRACT
Particle and radiation sources are widely employed in manifold applications. In the last decades, the upcoming of versatile, energetic, high-brilliance laser-based sources, as produced by intense laser-matter interactions, has introduced utilization of these sources in diverse areas, given their potential to complement or even outperform existing techniques. In this paper, we show that the interaction of an intense laser with a solid target produces a versatile, non-destructive, fast analysis technique that allows to switch from laser-driven PIXE (Particle-Induced X-ray Emission) to laser-driven XRF (X-ray Fluorescence) within single laser shots, by simply changing the atomic number of the interaction target. The combination of both processes improves the retrieval of constituents in materials and allows for volumetric analysis up to tens of microns and on cm2 large areas up to a detection threshold of ppms. This opens the route for a versatile, non-destructive, and fast combined analysis technique.
ABSTRACT
We present a technique for simultaneous focusing and energy selection of high-current, mega-electron volt proton beams with the use of radial, transient electric fields (10(7) to 10(10) volts per meter) triggered on the inner walls of a hollow microcylinder by an intense subpicosecond laser pulse. Because of the transient nature of the focusing fields, the proposed method allows selection of a desired range out of the spectrum of the polyenergetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, such as their broad spectrum and divergence at the source.
