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La spectroscopie laser ultrarapide est une technique spectroscopique qui utilise des lasers à impulsions ultracourtes pour l'étude de la dynamique sur des échelles de temps extrêmement courtes, de l'a

vignette|Dispositif expérimental de spectroscopie photoélectronique résolue en angle|alt=|300x300px La spectroscopie photoélectronique résolue en angle (ARPES), est une technique expérimentale direct

vignette|upright=1.5|Principe de fonctionnement du microscope électronique en transmission. vignette|Un microscope électronique en transmission (1976). La microscopie électronique en transmission (ME

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Nuclear Excitation by Free Muon Capture

Fabrizio Carbone, Simone Gargiulo, Ivan Madan

Efficient excitation of nuclei via exchange of a real or virtual photon has a fundamental importance for nuclear science and technology development. Here, we present a mechanism of nuclear excitation based on the capture of a free muon into the atomic orbits (NE mu C). The cross section of such a proposed process is evaluated using the Feshbach projection operator formalism and compared to other known excitation phenomena, i.e., photoexcitation and nuclear excitation by electron capture (NEEC), showing up to 10 orders of magnitude increase in cross section. NE mu C is particularly interesting for MeV excitations that become accessible thanks to the stronger binding of muons to the nucleus. The binding energies of muonic atoms have been calculated introducing a state of the art modification to the Flexible Atomic Code. An analysis of experimental scenarios in the context of modern muon production facilities shows that the effect can be detectable for selected isotopes. The total probability of NE mu C is predicted to be P approximate to 1 x 10-6 per incident muon in a beam-based scenario. Given the high transition energy provided by muons, NE mu C can have important consequences for isomer feeding and particle-induced fission.

AMER PHYSICAL SOC2022

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Ultrafast Transverse Modulation of Free Electrons by Interaction with Shaped Optical Fields

Francesco Barantani, Fabrizio Carbone, Simone Gargiulo, Ido Kaminer, Veronica Leccese, Ivan Madan, Alexey Sapozhnik, Phoebe Marie Tengdin, Giovanni Maria Vanacore

Spatiotemporal electron-beam shaping is a bold frontier of electron microscopy. Over the past decade, shaping methods evolved from static phase plates to low-speed electrostatic and magnetostatic displays. Recently, a swift change of paradigm utilizing light to control free electrons has emerged. Here, we experimentally demonstrate arbitrary transverse modulation of electron beams without complicated electron-optics elements or material nanostructures, but rather using shaped light beams. On-demand spatial modulation of electron wavepackets is obtained via inelastic interaction with transversely shaped ultrafast light fields controlled by an external spatial light modulator. We illustrate this method for the cases of Hermite-Gaussian and Laguerre-Gaussian modulation and discuss their use in enhancing microscope sensitivity. Our approach dramatically widens the range of patterns that can be imprinted on the electron profile and greatly facilitates tailored electron-beam shaping.

AMER CHEMICAL SOC2022

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We probe plasma dynamics with nm-fs resolution through electron spectroscopy performed in an ultrafast transmission electron microscope. This approach would allow to disentangle the dynamic evolution of plasma parameters and observe previously inaccessible energy inhomogeneities. (C) 2021 The Author(s)

IEEE2021

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