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Conceptual Design of a Laser Driver for a Plasma Accelerator User Facility
摘要： The purpose of the European project EuPRAXIA is to realize a novel plasma accelerator user facility. The laser driven approach sets requirements for a very high performance level for the laser system: pulse peak power in the petawatt range, pulse repetition rate of several tens of Hz, very high beam quality and overall stability of the system parameters, along with 24/7 operation availability for experiments. Only a few years ago these performances were considered unrealistic, but recent advances in laser technologies, in particular in the chirped pulse ampli?cation (CPA) of ultrashort pulses and in high energy, high repetition rate pump lasers have changed this scenario. This paper discusses the conceptual design and the overall architecture of a laser system operating as the driver of a plasma acceleration facility for di?erent applications. The laser consists of a multi-stage ampli?cation chain based CPA Ti:Sapphire, using frequency doubled, diode laser pumped Nd or Yb solid state lasers as pump sources. Speci?c aspects related to the cooling strategy of the main ampli?ers, the operation of pulse compressors at high average power, and the beam pointing diagnostics are addressed in detail.
关键词： Ti:Sapphire lasers,Chirped Pulse Ampli?cation,laser driven plasma acceleration
更新于2025-09-16 10:30:52
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Optimized x-ray sources for x-ray diffraction measurements at the Omega Laser Facility
摘要： The use of x-ray diffraction (XRD) measurements in laser-driven dynamic compression experiments at high-power laser facilities is becoming increasingly common. Diffraction allows one to probe in situ the transformations occurring at the atomic level at extreme conditions of pressure, temperature, and time scale. In these measurements, the x-ray source is generated by irradiation of a solid foil. Under certain laser drive conditions, quasimonochromatic He-α radiation is generated. Careful analysis of the x-ray source plasma spectra reveals that this radiation is not a single line emission and that monochromaticity is highly dependent on the laser irradiance. In this work, we analyze how the spectra emitted by laser-irradiated copper, germanium, and iron foils at the Omega Laser vary depending on different laser drive conditions and discuss the implications for XRD experiments.
关键词： laser irradiance,x-ray diffraction,Omega Laser Facility,quasimonochromatic He-α radiation,laser-driven dynamic compression
更新于2025-09-12 10:27:22
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Design and optimization of a laser-PIXE beamline for material science applications
摘要： Multi-MeV proton beams can be generated by irradiating thin solid foils with ultra-intense (>1018 W/cm2) short laser pulses. Several of their characteristics, such as high bunch charge and short pulse duration, make them a complementary alternative to conventional radio frequency-based accelerators. A potential material science application is the chemical analysis of cultural heritage (CH) artifacts. The complete chemistry of the bulk material (ceramics, metals) can be retrieved through sophisticated nuclear techniques such as particle-induced X-ray emission (PIXE). Recently, the use of laser-generated proton beams was introduced as diagnostics in material science (laser-PIXE or laser-driven PIXE): Coupling laser-generated proton sources to conventional beam steering devices successfully enhances the capture and transport of the laser-accelerated beam. This leads to a reduction of the high divergence and broad energy spread at the source. The design of our hybrid beamline is composed of an energy selector, followed by permanent quadrupole magnets aiming for better control and manipulation of the final proton beam parameters. This allows tailoring both, mean proton energy and spot sizes, yet keeping the system compact. We performed a theoretical study optimizing a beamline for laser-PIXE applications. Our design enables monochromatizing the beam and shaping its final spot size. We obtain spot sizes ranging between a fraction of mm up to cm scale at a fraction of nC proton charge per shot. These results pave the way for a versatile and tunable laser-PIXE at a multi-Hz repetition rate using modern commercially available laser systems.
关键词： hybrid beamline and beam manipulation,laser-PIXE,Cultural heritage,particle induced X-ray emission (PIXE),laser-driven proton acceleration,ion beam analysis
更新于2025-09-12 10:27:22
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The emission of γ-Ray beams with orbital angular momentum in laser-driven micro-channel plasma target
摘要： We investigated the emission of multi-MeV γ-Ray beams with orbital angular momentum (OAM) from the interaction of an intense circularly polarized (CP) laser with a micro-channel plasma target. The driving laser can generate high energy electrons via direct laser acceleration within the channel. By attaching a plasma foil as the reflecting mirror, the CP laser is reflected and automatically colliding with the electrons. High energy gamma-photons are emitted through inverse Compton scattering (ICS) during collision. three-dimensional particle-in-cell simulations reveal that the spin angular momentum (SAM) of the CP laser can be transferred to the OAM of accelerated electrons and further to the emitted gamma-ray beam. these results may guide future experiments in laser-driven gamma-ray sources using micro-structures.
关键词： micro-channel plasma target,orbital angular momentum,γ-Ray beams,inverse Compton scattering,laser-driven
更新于2025-09-12 10:27:22
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Laser-shock compression experiment on magnesium hydride
摘要： A dynamic high-pressure experiment was performed on magnesium hydride to measure the Hugoniot equation-of-state point using laser-driven shock waves. By measuring the mean shock velocity of MgH2 and the time-resolved shock velocity of the quartz reference, the Hugoniot state of MgH2 at 150 GPa was determined. The reliability of the data is ensured by using another reference material, polystyrene, which is next to the sample and is compressed by the same. This work validates the experimental methodology to obtain further high-pressure data of MgH2 with high accuracy.
关键词： Velocity interferometer,Magnesium hydride,Shock compression,Laser-driven shock,Hugoniot measurement
更新于2025-09-12 10:27:22
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Characterization of laser-driven proton acceleration from water microdroplets
摘要： We report on a proton acceleration experiment in which high-intensity laser pulses with a wavelength of 0.4 μm and with varying temporal intensity contrast have been used to irradiate water droplets of 20 μm diameter. Such droplets are a reliable and easy-to-implement type of target for proton acceleration experiments with the potential to be used at very high repetition rates. We have investigated the influence of the laser’s angle of incidence by moving the droplet along the laser polarization axis. this position, which is coupled with the angle of incidence, has a crucial impact on the maximum proton energy. Central irradiation leads to an inefficient coupling of the laser energy into hot electrons, resulting in a low maximum proton energy. the introduction of a controlled pre-pulse produces an enhancement of hot electron generation in this geometry and therefore higher proton energies. However, two-dimensional particle-in-cell simulations support our experimental results confirming, that even slightly higher proton energies are achieved under grazing laser incidence when no additional pre-plasma is present. illuminating a droplet under grazing incidence generates a stream of hot electrons that flows along the droplet’s surface due to self-generated electric and magnetic fields and ultimately generates a strong electric field responsible for proton acceleration. The interaction conditions were monitored with the help of an ultra-short optical probe laser, with which the plasma expansion could be observed.
关键词： high-intensity laser pulses,water microdroplets,particle-in-cell simulations,laser-driven,proton acceleration
更新于2025-09-11 14:15:04
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Laser-driven strong shocks with infrared lasers at intensity of 10 <sup>16</sup> W/cm <sup>2</sup>
摘要： We present the results of an experiment on laser-driven shock waves performed at the Prague Asterix Laser system (PALS), where the fundamental frequency of the laser (1315 nm) is used to launch a strong shock in planar geometry. The experiment aims to characterize both shock waves and hot electrons generated at intensities of ’ 1016 W=cm2. It is shown that, in these interaction conditions, hydrodynamics is strongly impacted by noncollisional mechanisms, and the role of the hot electrons, generated by parametric instabilities, is essential in determining shock dynamics.
关键词： laser-driven shock waves,parametric instabilities,hot electrons,hydrodynamics
更新于2025-09-11 14:15:04
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A multihertz, kiloelectronvolt pulsed proton source from a laser irradiated continuous hydrogen cluster target
摘要： A high-repetition rate laser-driven proton source from a continuously operating cryogenic hydrogen cluster target is presented. We demonstrate a debris-free, Coulomb-explosion based acceleration in the 10s of kilo-electron-volt range with a stability of about 10% in a 5 Hz operation. This acceleration mechanism, delivering short pulse proton bursts, represents an ideal acceleration scheme for various applications, for example, in materials science or as an injector source in conventional accelerators. Furthermore, the proton energy can be tuned by varying the laser and/or cluster parameters. 3D numerical particle-in-cell simulations and an analytical model support the experimental results and reveal great potential for further studies, scaling up the proton energies, which can be realized with a simple modification of the target.
关键词： high-repetition rate,laser-driven proton source,Coulomb-explosion,particle-in-cell simulations,cryogenic hydrogen cluster target
更新于2025-09-11 14:15:04
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Laser-driven production of the antihydrogen molecular ion
摘要： The feasibility of producing the molecular antihydrogen anion H2 in the laboratory is investigated. Utilizing reaction rates calculated here involving the interaction of laser excited-state antihydrogen atoms held in magnetic minimum traps, key processes are identified that could lead to anion production, as well as competing effects leading to anti-atom loss. These are discussed in the context of present-day and near-future experimental capabilities.
关键词： antihydrogen,magnetic traps,molecular ion,antimatter,laser-driven production
更新于2025-09-11 14:15:04