Publications associées à Formation of dislocation loops during He clustering in bcc Fe

Engineering SYK Interactions in Disordered Graphene Flakes under Realistic Experimental Conditions

Oleg Yazyev, Yifei Guan, Marta Agnieszka Brzezinska

We model interactions following the Sachdev-Ye-Kitaev (SYK) framework in disordered graphene flakes up to 300 000 atoms in size (-100 nm in diameter) subjected to an out-of-plane magnetic field B of 5-20 Tesla within the tight-binding formalism. We investi ...

AMER PHYSICAL SOC2023

Experimental study of stability, quench propagation and detection methods on 15 kA sub-scale HTS fusion conductors in SULTAN

Pierluigi Bruzzone, Kamil Sedlák, Nikolay Bykovskiy, Ortensia Dicuonzo

High-temperature superconductors (HTSs) enable exclusive operating conditions for fusion magnets, boosting their performance up to 20 T generated magnetic fields in the temperature range from 4 K to 20 K. One of the main technological issues of HTS conduct ...

2023

In situ work function measurements of W, WO3 nanostructured surfaces

Francisco Sanchez

Surface nanostructuring enables the fabrication of materials with highly desirable properties. Nanostructured tungsten surfaces have potential applications in solar water splitting. Exposing a polished tungsten surface to helium plasma induces various surf ...

ELSEVIER SCIENCE SA2022

How to improve the efficiency of a traditional dissolution dynamic nuclear polarization (dDNP) apparatus: Design and performance of a fluid path compatible dDNP/LOD-ESR probe

Jean-Noël Hyacinthe, Andrea Capozzi, Thanh Phong Kevin Lê

Dissolution Dynamic Nuclear Polarization (dDNP) was invented almost twenty years ago. Ever since, hardware advancement has observed 2 trends: the quest for DNP at higher field and, more recently, the development of cryogen free polarizers. Despite the DNP ...

Academic Press Inc - Elsevier Science2022

Directional detection of light dark matter from three-phonon events in superfluid He-4

Angelo Esposito

We present the analysis of a new signature for light dark matter detection with superfluid He-4: the emission of three phonons. We show that, in a region of mass below the MeV, the kinematics of this process can offer a way to reconstruct the dark matter i ...

American Physical Society2021

In situ control of the helical and skyrmion phases in Cu2OSeO3 using high-pressure helium gas up to 5 kbar

Arnaud Magrez, Henrik Moodysson Rønnow, Ivica Zivkovic, Jonathan White

We report a small-angle neutron scattering study of the helical and skyrmion lattice order in single-crystal Cu2OSeO3 under quasihydrostatic helium gas pressures up to 5 kbar. By using helium gas as the pressure-transmitting medium (PTM) we ensure pressure ...

AMER PHYSICAL SOC2020

Dark matter, dark photon and superfluid He-4 from effective field theory

Emma Michèle Ginette Geoffray, Angelo Esposito

We consider a model of sub-GeV dark matter whose interaction with the Standard Model is mediated by a new vector boson (the dark photon) which couples kinetically to the photon. We describe the possibility of constraining such a model using a superfluid He ...

2020

Light Dark Matter and Superfluid He-4 from EFT

Angelo Esposito

We study the response of a He-4 detector to the interaction of sub-GeV dark matter using an effective field theory for the superfluid. We compute the lifetime of the phonon, which agrees with what known from standard techniques, hence providing an importan ...

IOP PUBLISHING LTD2020

Sub-MeV dark matter and the Goldstone modes of superfluid helium

Angelo Esposito

We show how a relativistic effective field theory for the superfluid phase of 4 He can replace the standard methods used to compute the production rates of low-momentum excitations due to the interaction with an external probe. This is done by studying the ...

American Physical Society2019

Sub-GeV dark matter in superfluid He-4: an effective theory approach

Angelo Esposito

We employ an effective field theory to study the detectability of sub-GeV dark matter through its interaction with the gapless excitations of superfluid 4He. In a quantum field theory language, the possible interactions between the dark matter and the supe ...

Springer2019

Helium-induced electronic transitions in photo-excited Ba+–Hen exciplexes

Marcel Drabbels

The possibility for helium-induced electronic transitions in a photo-excited atom is investigated using Ba+ excited to the 6p 2P state as a prototypical example. A diabatization scheme has been designed to obtain the necessary potential energy surfaces and ...

2018

Investigations and numerical modeling of mechanical properties of tempered martensitic steel Eurofer97 at various loading rates, temperatures and after spallation irradiation

Serafin Knitel

The reduced activation tempered martensitic steel Eurofer97 is a reference steel for a structural applica-tions in fusion reactors. The first-wall and blanket materials will be subjected to high thermal and neutron fluxes and will experience very complex, ...

EPFL2018

Dependence of the L-Mode scrape-off layer power fall-off length on the upper triangularity in TCV

Holger Reimerdes, Stefano Coda, Benoît Labit, Christian Gabriel Theiler, Antoine Pierre Emmanuel Alexis Merle, Roberto Maurizio, Bernhard Sieglin

This paper reports on experimental observations on TCV with a scan in upper triangularity

{\delta }_{\mathrm{up}}

, including negative triangularity, focusing on the power fall-off length

{\lambda }_{{\rm{q}}}

in L-Mode. The upper triangularity is scann ...

2018

Helium effects on irradiation assisted stress corrosion cracking susceptibility of 316L austenitic stainless steel

Ignasi Villacampa Roses

The formation and growth of cracks by irradiation assisted stress corrosion cracking (IASCC) in light water reactor internals is a critical issue for a safe long-term operation of nuclear power plants. The IASCC susceptibility at relatively low dose is dom ...

EPFL2018

Dislocation Cross-Slip in Face-Centered Cubic Solid Solution Alloys

Wolfram Georg Nöhring

The mechanical strength of metals depends on their resistance against various microscopic deformation processes. In ductile metals, the most important process is shearing of the crystal lattice by dislocations. One of the fundamental aspects of dislocation ...

EPFL2018

Screw dislocation structure and mobility in body centered cubic Fe predicted by a Gaussian Approximation Potential

Nicola Marzari, William Curtin, Daniele Dragoni, Francesco Maresca

The plastic flow behavior of bcc transition metals up to moderate temperatures is dominated by the thermally activated glide of screw dislocations, which in turn is determined by the atomic-scale screw dislocation core structure and the associated kink-pai ...

2018

Properties of helium bubbles in covalent systems at the nanoscale: A combined numerical and experimental study

Cécile Hébert, Duncan Thomas Lindsay Alexander

The properties of nanometric-sized helium bubbles in silicon have been investigated using both spatially resolved electron-energy-loss spectroscopy combined with a recently developed method, and molecular-dynamics simulations. The experiments allowed for a ...

Amer Physical Soc2017

Cryogenic Ion Spectroscopy of Peptides and Glycans

Chiara Masellis

Understanding the structure of biomolecules, which are directly related to physiological processes that take place in the human body, has always generated a large interest in the scientific community. In this thesis we focus our attention on two of these c ...

EPFL2017

Novel Sample Formulations for Pure and Persistent Hyperpolarized Solutions via Dissolution Dynamic Nuclear Polarization

Basile Vuichoud

Nuclear Magnetic Resonance (NMR) spectroscopy allows one to study and analyze the structure, motions and interactions of a broad variety of molecules. However, this technique has a major inconvenience: its low sensitivity, which therefore often results in ...

EPFL2017

Comprehensive first-principles study of stable stacking faults in hcp metals

William Curtin, Zhaoxuan Wu, Binglun Yin

The plastic deformation in hcp metals is complex, with the associated dislocation core structures and properties not well understood on many slip planes in most hcp metals. A first step in establishing the dislocation properties is to examine the stable st ...

Elsevier2017