Enhancement of the laser-driven proton source at PHELIX

Hornung, J.; Zobus, Y.; Boller, P.; Brabetz, C.; Eisenbarth, U.; Kühl, T.; Major, Zs.; Ohland, J. B.; Zepf, M.; Zielbauer, B.; Bagnoud, V.

doi:10.1017/hpl.2020.23

Cited by 30 publications

(21 citation statements)

References 27 publications

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“…Despite numerous efforts both theoretically and experimentally, the gap remains, showing a clear deficiency in the understanding of the laser-plasma interaction at relativistic intensities. While many high-profile results have been published including proton energies approaching 100 MeV 6 , 7 , further progress requires a more detailed understanding of the interaction. For instance, the evolution of the target during the last instants, before the interaction with the peak intensity begins, requires a more thorough treatment, and subsequently one should control it to reach the ideal conditions for the desired outcome.…”

Section: Introductionmentioning

confidence: 99%

Time-resolved study of holeboring in realistic experimental conditions

et al. 2021

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The evolution of dense plasmas prior to the arrival of the peak of the laser irradiation is critical to understanding relativistic laser plasma interactions. The spectral properties of a reflected laser pulse after the interaction with a plasma can be used to gain insights about the interaction itself, whereas the effect of holeboring has a predominant role. Here we developed an analytical model, describing the non-relativistic temporal evolution of the holeboring velocity in the presence of an arbitrary overdense plasma density and laser intensity profile. We verify this using two-dimensional particle-in-cell simulations, showing a major influence on the holeboring dynamic depending on the density profile. The influence on the reflected laser pulse has been verified during an experiment at the PHELIX laser. We show that this enables the possibility to determine the sub-micrometer scale length of the preplasma by measuring the maximum holeboring velocity and acceleration during the laser-plasma interaction.

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Section: Introductionmentioning

confidence: 99%

Time-resolved study of holeboring in realistic experimental conditions

et al. 2021

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“…The higher proton energy reported for plastic targets, with several peaks surpassing 60 MeV [3,50,61] can be due to the increased coupling of the laser light into the target as demonstrated by Geng et al [73]. When plotted against the pulse duration, the results are again well separated, most high peaks being obtained for pulses longer than 400 fs, as shown in Figure 3B.…”

Section: Dielectric and Non-metallic Targetsmentioning

confidence: 59%

“…[2,40,50,61]. These results have been obtained at intensities in the range 10 20 -1.5 × 10 21 W cm −2 μm 2 .…”

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confidence: 61%

Target Characteristics Used in Laser-Plasma Acceleration of Protons Based on the TNSA Mechanism

et al. 2022

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The target normal sheath acceleration is a robust mechanism for proton and ion acceleration from solid targets when irradiated by a high power laser. Since its discovery extensive studies have been carried out to enhance the acceleration process either by optimizing the laser pulse delivered onto the target or by utilizing targets with particular features. Targets with different morphologies such as the geometrical shape (thin foil, cone, spherical, foam-like, etc.), with different structures (multi-layer, nano- or micro-structured with periodic striations, rods, pillars, holes, etc.) and made of different materials (metals, plastics, etc.) have been proposed and utilized. Here we review some recent experiments and characterize from the target point of view the generation of protons with the highest energy.

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“…Optimization of the proton source by directly comparing quantitatively these proton-source geometries has been conducted. Our findings show that, for the current PHELIX parameters, a proton source generated by irradiating 1 µm thick foils with P-polarized laser beams of the highest temporal contrast under 45 • incidence is the best trade-off 44 . After the initial setup and test, the source delivered reliably, on every shot, TNSA proton beams with 10 12 protons of energy higher than 15 MeV and with cut-off energy around 70 MeV .…”

Section: Experimental Methodsmentioning

confidence: 78%

First on-line detection of radioactive fission isotopes produced by laser-accelerated protons

Boller

Zylstra

Neumayer

et al. 2020

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The on-going developments in laser acceleration of protons and light ions, as well as the production of strong bursts of neutrons and multi-$$\hbox {MeV}$$ MeV photons by secondary processes now provide a basis for novel high-flux nuclear physics experiments. While the maximum energy of protons resulting from Target Normal Sheath Acceleration is presently still limited to around $$100 \, \hbox {MeV}$$ 100 MeV , the generated proton peak flux within the short laser-accelerated bunches can already today exceed the values achievable at the most advanced conventional accelerators by orders of magnitude. This paper consists of two parts covering the scientific motivation and relevance of such experiments and a first proof-of-principle demonstration. In the presented experiment pulses of $$200 \, \hbox {J}$$ 200 J at $$\approx \, 500 \, \hbox {fs}$$ ≈ 500 fs duration from the PHELIX laser produced more than $$10^{12}$$ 10 12 protons with energies above $$15 \, \hbox {MeV}$$ 15 MeV in a bunch of sub-nanosecond duration. They were used to induce fission in foil targets made of natural uranium. To make use of the nonpareil flux, these targets have to be very close to the laser acceleration source, since the particle density within the bunch is strongly affected by Coulomb explosion and the velocity differences between ions of different energy. The main challenge for nuclear detection with high-purity germanium detectors is given by the strong electromagnetic pulse caused by the laser-matter interaction close to the laser acceleration source. This was mitigated by utilizing fast transport of the fission products by a gas flow to a carbon filter, where the $$\upgamma$$ γ -rays were registered. The identified nuclides include those that have half-lives down to $$39 \, \hbox {s}$$ 39 s . These results demonstrate the capability to produce, extract, and detect short-lived reaction products under the demanding experimental condition imposed by the high-power laser interaction. The approach promotes research towards relevant nuclear astrophysical studies at conditions currently only accessible at nuclear high energy density laser facilities.

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Enhancement of the laser-driven proton source at PHELIX

Cited by 30 publications

References 27 publications

Time-resolved study of holeboring in realistic experimental conditions

Time-resolved study of holeboring in realistic experimental conditions

Target Characteristics Used in Laser-Plasma Acceleration of Protons Based on the TNSA Mechanism

First on-line detection of radioactive fission isotopes produced by laser-accelerated protons

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