A5000329011- Electron and X-Ray Spectroscopy Techniques
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Surface and Thin Film Phenomena
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- X-ray Spectroscopy and Fluorescence Analysis
- Semiconductor materials and devices
- Advanced Chemical Physics Studies
- Semiconductor materials and interfaces
- Advanced X-ray Imaging Techniques
- Atmospheric Ozone and Climate
- Atomic and Subatomic Physics Research
- Astrophysics and Star Formation Studies
- Particle physics theoretical and experimental studies
- Advanced Condensed Matter Physics
- Dark Matter and Cosmic Phenomena
- Advancements in Photolithography Techniques
- Magnetic and transport properties of perovskites and related materials
- Integrated Circuits and Semiconductor Failure Analysis
- Atmospheric chemistry and aerosols
- Ion-surface interactions and analysis
- Physics of Superconductivity and Magnetism
- Photocathodes and Microchannel Plates
- Diamond and Carbon-based Materials Research
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2015-2024
Cluster in Biomedicine
2024
Frascati Scienza
2013-2021
Eni (Italy)
1995-2021
Istituto Nazionale di Fisica Nucleare
1992-2021
European Organization for Nuclear Research
2003-2020
National Agency for New Technologies, Energy and Sustainable Economic Development
2018
Cornell University
2015
Institute of Structure of Matter
1991-2001
Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
1999-2001
We report the experimental observation of a light polarization rotation in vacuum presence transverse magnetic field. Assuming that data distribution is Gaussian, average measured (3.9 +/- 0.5) x 10(-12) rad/pass, at 5 T with 44 000 passes through 1 m long magnet, lambda = 1064 nm. The relevance this result terms existence light, neutral, spin-zero particle discussed.
Photoelectron spectra from metal overlayers on GaP(110) show that the photoionization light source may induce a surface photovoltage, causing an energy shift of valence- and core-level peaks. We analyze dependence this photovoltage coverage, substrate doping, temperature. The presence seriously affects determination band bending by photoelectron spectroscopy, technique which is generally thought to reflect equilibrium electronic structure metal-semiconductor interfaces.
In 2006 the PVLAS collaboration reported observation of an optical rotation generated in vacuum by a magnetic field. To further check against possible instrumental artifacts, several upgrades to apparatus have been made during past year. Two data taking runs, at wavelength 1064 nm, performed new configuration with field strengths 2.3 and 5 T. The T value was chosen order avoid stray fields. observations do not show presence signal down levels...
Present and future accelerators' performances may be limited by the electron cloud (EC) effect. The EC formation evolution are determined wall-surface properties of accelerator vacuum chamber. We present measurements total secondary yield (SEY) related energy distribution curves electrons as a function incident-electron energy. Particular attention has been paid to emission process due very low-energy primary ($<20\text{ }\text{ }\mathrm{e}\mathrm{V}$). It is shown that SEY approaches unity...
A set of extra peaks, which dominate the region silver s-p band, are observed in angle-resolved photoemission from Ag islands formed on GaAs(110) by low temperature deposition and annealing to room temperature. The thickness dependence peak spacing demonstrates that new peaks originate wave vector quantization due electron confinement. overall features spectra reproduced within a model based superposition emission distribution island sizes, interpreted as quantum size effects these small...
We performed a combined secondary electron yield (SEY) and x-ray photoelectron spectroscopy study as function of the dose energy on Cu technical surface representative LHC accelerator walls. The bombardment is accompanied by clear chemical modification, indicating an increased graphitization SEY decreases. decrease in also found to depend significantly kinetic primary electrons. When low-energy electrons are employed (E≤20 eV), reduction slower smaller magnitude than when higher-energy used....
Low energy electrons in accelerators are known to interact with the circulating beam, giving rise formation of a so-called e - cloud. Such cloud may induce detrimental effects on accelerated beam quality and stability. Those have been observed most positively charged particles. A longstanding effort has so far devoted understand detail physical origin such cloud, its build-up interaction beam. We will first describe basic features causing accelerators, then we review some theoretical work...
On the wake of results obtained so far at SPARC_LAB test-facility Laboratori Nazionali di Frascati (Italy), we are currently investigating possibility to design and build a new multi-disciplinary user-facility, equipped with soft X-ray Free Electron Laser (FEL) driven by ∼1 GeV high brightness linac based on plasma accelerator modules. This study is performed in synergy EuPRAXIA study. In this paper report about recent progresses going facility.
We investigate the electronic structure of Ca$_{1-x}$Sr$_x$VO$_3$ using photoemission spectroscopy. Core level spectra establish an phase separation at surface, leading to distinctly different surface compared bulk. Analysis this system allowed us separate and bulk contributions. These results help understand properties related two vastly differing energy-scales, namely low energy-scale thermal excitations (~$k_{B}T$) high-energy scale Coulomb other interactions.
We have investigated the electronic and magnetic structures of Sr(2)FeMoO(6) employing site-specific direct probes, namely x-ray absorption spectroscopy with linearly circularly polarized photons. In contrast to some previous suggestions, results clearly establish that Fe is in formal trivalent state this compound. With help light, it unambiguously shown moment at Mo sites below limit detection (<0.25 mu(B)), resolving a controversy. also show decrease observed magnetization measurements...
Secondary electron yield (SEY) curves in the 0-1000 eV range were measured on polycrystalline Ag, Au and Cu samples. The metals examined as introduced ultra-high vacuum chamber after having been cleaned by Ar+ ion sputtering. comparison between clean samples presence of contaminants, due to permanence atmosphere, confirmed that SEY behavior is strongly influenced chemical state metal surface. We show when using very slow primary electrons sample work function can be determined with high...
Multiple human impacts on natural ecosystems cause ongoing widespread habitat loss, with consequent decline of biodiversity and ecosystem services. Seas oceans, the largest biomes biosphere, show increasing numbers degraded habitats. Ecological restoration offers a major tool to reverse this trend recover biodiversity, along health well‐being. The United Nations Decade Ecosystem Restoration promotes global‐scale habitats we can exploit lessons learned from terrestrial projects improve...
We have investigated the electronic and magnetic structures of Sr2FeMoO6 employing site-specific direct probes, namely x-ray absorption spectroscopy with linearly circularly polarized photons. In contrast to some previous suggestions, results clearly establish that Fe is in formal trivalent state this compound. With help light, it unambiguously shown moment at Mo sites below limit detection (<0.25 µB), resolving a controversy. also show decrease observed magnetization measurements from...
Experimental bounds on induced vacuum magnetic birefringence can be used to improve present photon-photon scattering limits in the electronvolt energy range. Measurements with Polarizzazione del Vuoto con Laser apparatus [E. Zavattini et al., Phys. Rev. D 77, 032006 (2008)] at both $\ensuremath{\lambda}=1064$ and 532 nm lead parameter ${A}_{e}$, describing nonlinear effects QED, of ${A}_{e}^{(1064)}<6.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21}\text{ }\text{...
The secondary emission yield (SEY) properties of colaminated Cu samples for LHC beam screens are correlated to the surface chemical composition determined by x-ray photoelectron spectroscopy. as-received is characterized presence significant quantities contaminating adsorbates and maximum SEY curve (${\ensuremath{\delta}}_{\mathrm{max}}$) being as high 2.1. After extended electron scrubbing at kinetic energy 10 500 eV, ${\ensuremath{\delta}}_{\mathrm{max}}$ value drops ultimate values 1.35...
The secondary electron yield for low primary-electron energies is shown to strongly depend on the exact surface conditions, with significant implications threshold of electron-cloud build up in proton storage rings.
ABSTRACT Original phase equilibria data on asphaltenic mixtures show that the principal modellistic approaches described in literature do not accurately reproduce asphaltene behaviour. A new, more reliable approach is proposed this paper, and a procedure for predicting stability of solutions outlined. Application new model to two oils gives satisfactory results when compared with field observations.
Initiating Auger transitions using tunable monochromatic x rays from synchrotron, we show that the satellite intensities in ${L}_{2}$${M}_{45}$${M}_{45}$ and ${L}_{3}$${M}_{45}$${M}_{45}$ spectra of Cu Zn increase with increasing photon energies up to about 200 eV above thresholds. This indicates a pronounced influence history core-hole generation on spectra, sharp contrast universally accepted belief, suggests breakdown sudden approximation. Details energy dependence intensity provide new...
The design of a future multi-TeV muon collider needs new ideas to overcome the technological challenges related production, cooling, accumulation and acceleration. In this paper layout positron driven source known as Low EMittance Muon Accelerator (LEMMA) concept is presented. beam, stored in ring with high energy acceptance low emittance, extracted multi-target system, produce pairs at threshold. This solution alleviates issues power deposited integrated Peak Energy Density Deposition...