Publications associées à Laser à électrons libres

Numerical Study of the Attosecond Free-Electron Laser Pulse Generation in the Soft X-ray Regime at the SwissFEL

Isolated attosecond pulses from an X-ray free-electron laser are in high demand for attosecond science, which enables the probing of electron dynamics by X-ray nonlinear spectroscopy and single-particle imaging. The aim of this thesis is to simulate attos ...

EPFL2024

Energy-Efficient Particle Accelerators for Research

Mike Seidel

Particle accelerators are the drivers for large-scale research infrastructures for particle physics but also for many branches of condensed matter research. The types of accelerator-driven research infrastructures include particle colliders, neutron, muon ...

2024

Characterization of Transverse Instabilities Driven by Electron Cloud

Sofia Carolina Johannesson

Electron cloud continues to be one of the main limiting factors of the Large Hadron Collider (LHC), the biggest accelerator at CERN. These clouds form in the beam chamber when positively charged particles are passing through and cause unwanted effects in b ...

EPFL2024

Hosing of a Long Relativistic Particle Bunch in Plasma

Ambrogio Fasoli, Ivo Furno, Patrick Blanchard, Yanis Andrebe, Riccardo Agnello, Christine Stollberg, Sun Hee Kim, Alban Sublet, Shuai Liu

Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven by a short, misaligned preceding bunch. Hosing develops in the plane of misalignment, selfmodulation in the perpendicular plane, at frequencies clo ...

Amer Physical Soc2024

Toward a brightness upgrade to the SwissFEL: A high gradient traveling-wave rf photogun

Mike Seidel, Sven Reiche, Paolo Craievich, Anastasiya Magazinik

The first generation of S-band injectors for free-electron lasers has illustrated high reliability and performance by driving the latest generation of high brightness machines. However, the ultimate electron beam brightness of these devices is limited by t ...

Amer Physical Soc2023

Progress and prospects in nonlinear extreme-ultraviolet and X-ray optics and spectroscopy

Majed Chergui

Free-electron lasers and high-harmonic-generation table-top systems are new sources of extreme-ultraviolet to hard X-ray photons, providing ultrashort pulses that are intense, coherent and tunable. They are enabling a broad range of nonlinear optical and s ...

NATURE PORTFOLIO2023

Charge Dynamics Electron Microscopy Nanoscale Imaging of Femtosecond Plasma Dynamics

Fabrizio Carbone, Ivan Madan, Thomas La Grange, Giovanni Maria Vanacore, Gabriele Berruto, Ido Kaminer, Simone Gargiulo, Luca Piazza, Francesco Barantani, Tom Theodorus Antonius Lummen

Understanding and actively controlling the spatiotemporal dynamics of nonequilibrium electron clouds is fundamental for the design of light and electron sources, high power electronic devices, and plasma-based applications. However, electron clouds evolve ...

AMER CHEMICAL SOC2023

Element- and enantiomer-selective visualization of molecular motion in real-time

Majed Chergui, Malte Oppermann, Jérémy Raymond Jean Maurice Rouxel

Ultrafast optical-domain spectroscopies allow to monitor in real time the motion of nuclei in molecules. Achieving element-selectivity had to await the advent of time resolved X-ray spectroscopy, which is now commonly carried at X-ray free electron lasers. ...

Nature Portfolio2023

Transfer learning application of self-supervised learning in ARPES

Gabriel Aeppli

There is a growing recognition that electronic band structure is a local property of materials and devices, and there is steep growth in capabilities to collect the relevant data. New photon sources, from small-laboratory-based lasers to free electron lase ...

IOP Publishing Ltd2023

Generation and control of localized terahertz fields in photoemitted electron plasmas

Fabrizio Carbone, Ivan Madan, Giovanni Maria Vanacore, Ido Kaminer, Simone Gargiulo, Francesco Barantani

Dense micron-sized electron plasmas, such as those generated upon irradiation of nanostructured metallic surfaces by intense femtosecond laser pulses, constitute a rich playground to study light-matter interactions, many-body phenomena, and out-of-equilibr ...

ROYAL SOC CHEMISTRY2023

Engineering Absorption for Foil Applications

Sebastian Mader

Light matter interactions such as extinction, reflection, and transmission can be described by classical optics. Dur-ing the past decades, research focused on a novel resonant extinction type called plasmonics that allows for en-hancement of both types of ...

EPFL2022

Analytics at the nanometer and nanosecond scales by short electron pulses in an electron microscope

Thomas La Grange

Chemical reactions and phase transformations in nanometer-size objects may happen at very short timescales, so conventional characterization tools are not applicable. A new technique combining high spatial and temporal resolution is ultrafast (or dynamic) ...

SPRINGER2022

Beware of beam damage under reaction conditions: X-ray induced photochemical reduction of supported VOx catalysts during in situ XAS experiments

Oliver Kröcher, Davide Ferri, Anna Zabilska, Olga Safonova

In situ X-ray absorption spectroscopy (XAS) is a powerful technique for the investigation of heterogeneous catalysts and electrocatalysts. The obtained XAS spectra are usually interpreted from the point of view of the investigated chemical processes, there ...

ROYAL SOC CHEMISTRY2022

Synchrotron Radiation and Sensors: A History of Synergies

Giorgio Margaritondo

Synchrotron radiation has emerged over more than one-half century as a gigantic worldwide enterprise involving tens of thousands of researchers. Its history has been continuously and strongly linked to the technical progress of sensors. We review here diff ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2021

Emittance growth suppression with a multibunch feedback in high-energy hadron colliders: Numerical optimization of the gain and bandwidth

Xavier Buffat, Sondre Vik Furuseth

A transverse feedback system can effectively mitigate the emittance growth caused by injection oscillations and machine noise in hadron beams. However, as its action on the beam depends on beam position measurements of finite accuracy, it introduces additi ...

2021

Highly efficient THz four-wave mixing in doped silicon

Gabriel Aeppli

Third-order non-linearities are important because they allow control over light pulses in ubiquitous high-quality centro-symmetric materials like silicon and silica. Degenerate four-wave mixing provides a direct measure of the third-order non-linear sheet ...

SPRINGERNATURE2021

Demonstration of Near-field THz Spectroscopy Using Ultrafast Electron Microscopy

Fabrizio Carbone, Giovanni Maria Vanacore, Ido Kaminer, Kangpeng Wang

We probe near-field THz pulses with nm-fs spatio-temporal resolution, through their interaction with free-electron pulses in an ultrafast transmission electron microscope. Our experiment can help understand THz generation and nanoscale THz phenomena. (C) 2 ...

IEEE2021

Relation between Inner Structural Dynamics and Ion Dynamics of Laser-Heated Nanoparticles

Christoph Bostedt

When a nanoparticle is irradiated by an intense laser pulse, it turns into a nanoplasma, a transition that is accompanied by many interesting nonequilibrium dynamics. So far, most experiments on nanoplasmas use ion measurements, reflecting the outside dyna ...

American Physical Society2021

High-Resolution Transmission Electron Microscopy with Bright Microsecond Electron Pulses

Marcel Drabbels, Ulrich Lorenz, Pavel Olshin, Gabriele Bongiovanni

Transmission electron microscopy at atomic-resolution is a crucial tool in a variety of fields, ranging from materials science to biology. [1,2] Fast electron cameras have recently enabled high-speed observations atomic resolution. [3] Moreover, they have ...

2021

L-mode plasmas analyses and current ramp-up predictions for a JT-60SA hybrid scenario

Timothy Goodman, Javier García Hernández, Matteo Vallar

In this work, L-mode analyses are performed in order to assess a modeling framework for the prediction of electron cyclotron resonant heating (ECRH) -assisted current ramp-up phases for JT-60SA tokamak hybrid scenario #4-2. We compare two turbulence transp ...

IOP PUBLISHING LTD2021