arXiv subjects

C. Masciovecchio

Publications and source records attributed to C. Masciovecchio.

13 recordsLinked to original sources

arXiv2026

Report on the Advanced Linear Collider Study Group (ALEGRO) Workshop 2026

The 7th ALEGRO workshop, hosted by INFN Frascati National Laboratories from 3rd to 5th March 2026, brought together the international Advanced Novel Accelerators (ANA) community to discuss the role of advanced wakefield accelerators (AWA) in particle and high-energy physics. Organized under the ICFA-ANA panel, the workshop highlighted recent progress in plasma- and structure-based wakefield acceleration and strengthened international collaboration toward future energy-frontier colliders. A major focus was the ongoing 10 TeV linear collider design study, launched in 2025 following the US P5 recommendations. A dedicated session covered accelerator concepts, enabling technologies, and the associated physics case, while recognizing that future priorities will depend on the outcome of the European Strategy for Particle Physics Update. The workshop also reviewed nearer-term applications of advanced accelerators, including fixed-target experiments, injectors for future colliders and light sources, plasma-based Higgs factory concepts, and proton-driven plasma wakefield acceleration. Beyond high-energy physics, sessions covered free-electron lasers, synchrotron light sources, and strong-field QED. Recent demonstrations of FEL lasing with plasma-accelerated electron beams highlighted significant progress in beam quality and accelerator performance. Operational challenges for reliable user facilities, including high-availability laser and electron-beam systems, were discussed alongside the growing role of artificial intelligence and machine learning for accelerator optimization and control. This report summarizes the workshop discussions and conclusions from the chairs, together with short contributions from the presenters, providing an overview of the current status and future prospects of advanced wakefield accelerators.

physics.acc-ph↗

arXiv2026

Time-domain extreme ultraviolet diffuse scattering spectroscopy of nanoscale surface phonons

We report the observation of dynamic fringe patterns in the diffuse scattering of extreme ultraviolet light from surfaces, following femtosecond optical excitation. At each point on the detector, the diffuse scattering intensity exhibits oscillations at well-defined frequencies that correspond to surface phonons with wave vectors determined by the scattering geometry, indicating that the optical excitation generates coherent surface phonons propagating in all directions and spanning a wavelength range from 60 to 300 nm. This phenomenon is observed on a variety of samples, including single-layer and multilayer metal films, as well as bulk semiconductors. The measured surface phonon dispersions show good agreement with theoretical calculations. By comparing signal amplitudes from samples with different surface morphologies, we find that the excitation mechanism is linked to the natural surface roughness of the samples. However, the signal is still detectable on extremely smooth surfaces with sub-nanometer roughness. Our findings demonstrate a simple and effective method for optically exciting coherent surface phonons with nanoscale wavelengths on a wide range of solid samples and establish a foundation for surface phonon spectroscopy in a wave vector range well beyond the limit of conventional surface Brillouin scattering.

cond-mat.mtrl-sci↗

arXiv2024

A New Route for the Determination of Protein Structure and Function

Understanding complex biological macromolecules, especially proteins, is vital for grasping their diverse chemical functions with direct impact in biology and pharmacology. While techniques like X-ray crystallography and cryo-electron microscopy have been valuable, they face limitations such as radiation damage and difficulties in crystallizing certain proteins. X-ray free-electron lasers (XFELs) offer promising solutions with their ultrafast, high-intensity pulses, potentially enabling structural determination before radiation damage occurs. However, challenges like low signal-to-noise ratio persist, particularly for single protein molecules. To address this, we propose a new method involving engineered protein scaffolds to create ordered arrays of proteins with controlled orientations, aiming at enhancing the signal at the detector. This innovative strategy has the potential to address signal limitations and protein crystallization issues, opening avenues for determining protein structures under physiological conditions. Moreover, it holds promise for studying conformational changes resulting from photo-induced changes, protein-drug and/or protein-protein interactions. Indeed, the prediction of protein-protein interactions, fundamental to numerous biochemical and cellular processes, and the time-dependent conformational changes they undergo, continue to pose a considerable challenge in biology and biochemistry.

q-bio.BM↗

arXiv2024

Structured illumination microscopy with extreme ultraviolet pulses

The relentless pursuit of understanding matter at ever-finer scales has pushed optical microscopy to surpass the diffraction limit and produced the super-resolution microscopy which enables visualizing structures shorter than the wavelength of light. In the present work, we harnessed extreme ultraviolet beams to create a sub-μm grating structure, which was revealed by extreme ultraviolet structured illumination microscopy. This achievement marks the first step toward extending such a super-resolution technique into the X-ray regime, where achieving atomic-scale resolution becomes a charming possibility.

physics.optics↗

arXiv2022

Extreme ultraviolet transient gratings: A tool for nanoscale photoacoustics

Collective lattice dynamics determine essential aspects of condensed matter, such as elastic and thermal properties. These exhibit strong dependence on the length-scale, reflecting the marked wavevector dependence of lattice excitations. The extreme ultraviolet transient grating (EUV TG) approach has demonstrated the potential of accessing a wavevector range corresponding to the 10s of nm length-scale, representing a spatial scale of the highest relevance for fundamental physics and forefront technology, previously inaccessible by optical TG and other inelastic scattering methods. In this manuscript we report on the capabilities of this technique in the context of probing thermoelastic properties of matter, both in the bulk and at the surface, as well as discussing future developments and practical considerations.

cond-mat.mtrl-sci↗

arXiv2020

Nanoscale transient magnetization gratings excited and probed by femtosecond extreme ultraviolet pulses

We utilize coherent femtosecond extreme ultraviolet (EUV) pulses derived from a free electron laser (FEL) to generate transient periodic magnetization patterns with periods as short as 44 nm. Combining spatially periodic excitation with resonant probing at the dichroic M-edge of cobalt allows us to create and probe transient gratings of electronic and magnetic excitations in a CoGd alloy. In a demagnetized sample, we observe an electronic excitation with 50 fs rise time close to the FEL pulse duration and ~0.5 ps decay time within the range for the electron-phonon relaxation in metals. When the experiment is performed on a sample magnetized to saturation in an external field, we observe a magnetization grating, which appears on a sub-picosecond time scale as the sample is demagnetized at the maxima of the EUV intensity and then decays on the time scale of tens of picoseconds via thermal diffusion. The described approach opens prospects for studying dynamics of ultrafast magnetic phenomena on nanometer length scales.

cond-mat.mes-hall↗

arXiv2019

Synchrotron-based UV resonance Raman scattering for investigating ionic liquid-water solutions

This work shows that bulk ionic liquids (ILs) and their water solution can be conveniently investigated by synchrotron-based UV resonance Raman (UVRR) spectroscopy. The main advantages of this technique for the investigation of the local structure and intermolecular interactions in imidazolium-based ILs are presented and discussed. The unique tunability of synchrotron source allows one to selectively enhance in the Raman spectra the vibrational signals arising from the imidazolium ring. Such signals showed good sensitivity to the modifications induced in the local structure of ILs by i) the change of anion and ii) the progressively longer alkyl chain substitution on the imidazolium ring. Moreover, some UVRR signals are specifically informative on the effect induced by addition of water on the strength of cation-anion H-bonds in IL-water solutions. All of these results corroborate the potentiality of UVRR to retrieve information on the intermolecular interactions in IL-water solutions, besides the counterpart obtained by employing on these systems the spontaneous Raman scattering technique.

cond-mat.soft↗

arXiv2018

EuPRAXIA@SPARC_LAB Design study towards a compact FEL facility at LNF

On the wake of the results obtained so far at the SPARC\_LAB test-facility at the Laboratori Nazionali di Frascati (Italy), we are currently investigating the possibility to design and build a new multi-disciplinary user-facility, equipped with a soft X-ray Free Electron Laser (FEL) driven by a $\sim$1 GeV high brightness linac based on plasma accelerator modules. This design study is performed in synergy with the EuPRAXIA design study. In this paper we report about the recent progresses in the on going design study of the new facility.

physics.acc-ph↗

arXiv2000

The nature of the short wavelength excitations in vitreous silica: X-Rays Brillouin scattering study

The dynamical structure factor (S(Q,E)) of vitreous silica has been measured by Inelastic X-ray Scattering varying the exchanged wavevector (Q) at fixed exchanged energy (E) - an experimental procedure that, contrary to the usual one at constant Q, provides spectra with much better identified inelastic features. This allows the first direct evidence of Brillouin peaks in the S(Q,E) of SiO_2 at energies above the Boson Peak (BP) energy, a finding that excludes the possibility that the BP marks the transition from propagating to localised dynamics in glasses.

cond-mat.dis-nn↗

arXiv2000

Crystal-like high frequency phonons in the amorphous phases of solid water

The high frequency dynamics of low- (LDA) and high-density amorphous-ice (HDA) and of cubic ice (I_c) has been measured by inelastic X-ray Scattering (IXS) in the 1-15 nm^{-1} momentum transfer (Q) range. Sharp phonon-like excitations are observed, and the longitudinal acoustic branch is identified up to Q = 8nm^{-1} in LDA and I_c and up to 5nm^{-1} in HDA. The narrow width of these excitations is in sharp contrast with the broad features observed in all amorphous systems studied so far. The "crystal-like" behavior of amorphous ices, therefore, implies a considerable reduction in the number of decay channels available to sound-like excitations which is assimilated to low local disorder.

cond-mat.stat-mech↗

arXiv1999

Non-dynamic origin of the acoustic attenuation at high frequency in glasses

The sound attenuation in the THz region is studied down to T=16 K in glassy glycerol by inelastic x-ray scattering. At striking variance with the decrease found below 100 K in the GHz data, the attenuation in the THz range does not show any T dependence. This result i) indicates the presence of two different attenuation mechanisms, active respectively in the high and low frequency limits; ii) demonstrates the non-dynamic origin of the attenuation of THz sound waves, and confirms a similar conclusion obtained in SiO2 glass by molecular dynamics; and iii) supports the low frequency attenuation mechanism proposed by Fabian and Allen (Phys.Rev.Lett. 82, 1478 (1999)).

cond-mat.dis-nn↗

arXiv1999

Acoustic Nature of the Boson Peak in Vitreous Silica

New temperature dependent inelastic x-ray (IXS) and Raman (RS) scattering data are compared to each other and with existing inelastic neutron scattering data in vitreous silica (v-SiO_2), in the 300 - 1775 K region. The IXS data show collective propagating excitations up to Q=3.5 nm^-1. The temperature behaviour of the excitations at Q=1.6 nm^-1 matches that of the boson peak found in INS and RS. This supports the acoustic origin of the excess of vibrational states giving rise to the boson peak in this glass.

cond-mat.dis-nn↗

arXiv1999

Phonon-like and single particle dynamics in liquid lithium

The dynamic structure factor, S(Q,E), of liquid lithium (T=475 K) has been determined by inelastic x-ray scattering (IXS) in the momentum transfer region (Q = 1.4-110 nm-1). These data allow to observe how, in a simple liquid, a phonon-like collective mode evolves towards the single particle dynamics. As a function of Q, one finds: i) at low Q's, a sound mode with a positive dispersion of the sound velocity, ii) at intermediate Q's, excitations whose energy oscillates similarly to phonons in the crystal Brillouin zones, and iii) at high Q's, the S(Q,E) approaches a Gaussian shape, indicating that the single particle dynamics has been reached.

cond-mat.dis-nn↗