- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Free Electron Laser Performance within the EuPRAXIA Facility
摘要： Over the past 90 years, particle accelerators have evolved into powerful and widely used tools for basic research, industry, medicine, and science. A new type of accelerator that uses plasma wakefields promises gradients as high as some tens of billions of electron volts per meter. This would allow much smaller accelerators that could be used for a wide range of fundamental and applied research applications. One of the target applications is a plasma-driven free-electron laser (FEL), aiming at producing tunable coherent light using electrons traveling in the periodic magnetic field of an undulator. In this work, the plasma-based electron beams with the most promising qualities, designed in the framework of EuPRAXIA, are analyzed in terms of the FEL performance.
关键词： free-electron laser,undulator magnet,laser–plasma accelerator
更新于2025-09-23 15:19:57
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Shielding a monoenergetic photon source for nonproliferation applications analysis
摘要： Near-monoenergetic photon sources offer appealing improvements over broad-band bremsstrahlung sources when applied to challenges in nonproliferation efforts. The use of a laser-plasma accelerator offers electrons at the energies needed for multi-MeV Thomson sources in a compact form factor. Because these electrons have energy up to approximately 0.5 GeV, many energetic photons and neutrons are created as they are dumped out of the beam line. This fact creates challenges for performing experiments to demonstrate the advantages of such a photon source for nonproliferation applications in the short term, until effective methods for decelerating the electrons are developed. To mitigate these background particles for laboratory measurements, a system of beam dumps and secondary collimators has been designed. Once background flux is reduced to the lowest practical level, it is compared to the expected flux created by the source photon beam on a lead target. This simulation mimics a nonproliferation application by predicting measured flux off-axis from an interrogated high-Z object as a surrogate for special nuclear material. Background mitigation techniques are also expanded to a mobile interrogation case. These methods allow for demonstration of nonproliferation applications of near-monoenergetic photon sources and future deployment in the field.
关键词： Photonuclear,Active interrogation,Laser plasma accelerator,Nonproliferation,Monoenergetic photon source
更新于2025-09-19 17:15:36
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High-efficiency neutron source generation from photonuclear reactions driven by laser plasma accelerator
摘要： We experimentally demonstrate the generation of an electron beam with the charge of about 200 pC, the divergence of about 7 mrad and the maximum energy of about 320 MeV from helium gas via self-injection induced by self-evolved laser pulses (3 J, 30 fs) in the plasma channel. Based on the experimental electron beam parameters, the Monte Carlo simulation code Geant4 was used to optimize the thicknesses of converters for high yield neutrons. The Monte Carlo simulation results show that the simulation neutron number can reach as high as 107 with a 5-cm-thick Pb converter, and the corresponding energy range was about 100 keV~ 1 MeV. In this work, the neutrons were detected by four bubble detectors, and the neutron yield was measured to be 3.2×107/shot and distributed isotropically. Moreover, the neutron generation efficiency is about 1.1×107/J which to best of our knowledge, is the highest compared with other laser neutron generation methods with the same laser energy. Such a laser driven pulsed neutron source could be applied to different fields like the neutron absorption spectroscopy, material science, and nuclear physics, etc.
关键词： laser plasma accelerator,fast neutron,photonuclear reaction
更新于2025-09-19 17:13:59
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Polarized proton beams from a laser-plasma accelerator
摘要： We report on the concept of an innovative laser-driven plasma accelerator for polarized proton (or deuteron) beams with a kinetic energy up to several GeV. In order to model the motion of the particle spins in the plasmas, these have been implemented as an additional degree of freedom into the Particle-in-Cell simulation code VLPL. For the experimental realization, a polarized HCl gas-jet target is under construction, where the degree of proton polarization is determined with a Lamb-shift polarimeter. The final experiments, aiming at the first observation of a polarized particle beam from laser-generated plasmas, will be carried out at the 10 PW laser system SULF at SIOM/Shanghai.
关键词： laser-plasma accelerator,particle-in-cell simulations,Polarized proton beams
更新于2025-09-16 10:30:52
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A laser-plasma accelerator driven by two-color relativistic femtosecond laser pulses
摘要： A typical laser-plasma accelerator (LPA) is driven by a single, ultrarelativistic laser pulse from terawatt- or petawatt-class lasers. Recently, there has been some theoretical work on the use of copropagating two-color laser pulses (CTLP) for LPA research. Here, we demonstrate the first LPA driven by CTLP where we observed substantial electron energy enhancements. Those results have been further confirmed in a practical application, where the electrons are used in a bremsstrahlung-based positron generation configuration, which led to a considerable boost in the positron energy as well. Numerical simulations suggest that the trailing second harmonic relativistic laser pulse is capable of sustaining the acceleration structure for much longer distances after the preceding fundamental pulse is depleted in the plasma. Therefore, our work confirms the merits of driving LPAs by two-color pulses and paves the way toward a downsizing of LPAs, making their potential applications in science and technology extremely attractive and affordable.
关键词： positron generation,electron energy enhancements,laser-plasma accelerator,two-color laser pulses,numerical simulations
更新于2025-09-12 10:27:22
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Laser and electron deflection from transverse asymmetries in laser-plasma accelerators
摘要： We report on the de?ection of laser pulses and accelerated electrons in a laser-plasma accelerator (LPA) by the effects of laser pulse front tilt and transverse density gradients. Asymmetry in the plasma index of refraction leads to laser steering, which can be due to a density gradient or spatiotemporal coupling of the laser pulse. The transverse forces from the skewed plasma wave can also lead to electron de?ection relative to the laser. Quantitative models are proposed for both the laser and electron steering, which are con?rmed by particle-in-cell simulations. Experiments with the BELLA Petawatt Laser are presented which show controllable 0.1–1 mrad laser and electron beam de?ection from laser pulse front tilt. This has potential applications for electron beam pointing control, which is of paramount importance for LPA applications.
关键词： electron de?ection,transverse density gradients,laser-plasma accelerator,laser steering,pulse front tilt
更新于2025-09-12 10:27:22