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We present the conceptual design of a compact light source named BriXSinO. BriXSinO was born as demonstrator of the Marix project, but it is also a dual high flux radiation source Inverse Compton Source (ICS) of X-ray and Free-Electron Laser of THz spectral range radiation conceived for medical applications and general applied research. The accelerator is a push-pull CW-SC Energy Recovery Linac (ERL) based on superconducting cavities technology and allows to sustain MW-class beam power with almost just one hundred kW active power dissipation/consumption. ICS line produces 33 keV monochromatic X-Rays via Compton scattering of the electron beam with a laser system in Fabry-Pérot cavity at a repetition rate of 100 MHz. The THz FEL oscillator is based on an undulator imbedded in optical cavity and generates THz wavelengths from 15 to 50 micron., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

High order modes (HOMs) in multi-cell superconducting cavities are of particular concern in beam dynamics of linear accelerators, mainly those operating in CW mode with high current and high repetition rate. These undesired modes may invoke beam instabilities, beam breakup and increase the energy spread if not correctly pulled out and damped. The study reported in this paper is applied for damping the HOMs in the main Linac of BriXSinO, an ongoing project of an Energy Recovery Linac at LASA INFN laboratory. We developed a numerical model to study the interaction of monopole HOMs with the beam in long timescale. The presented model, named HOMEN (High Order Modes Evolution based on eNergy budget), allows the evaluation of the loss factor Kloss, crucial for evaluating the perturbing modes. At the same time, electromagnetic simulations of the standing wave multicell cavity, highlighted the dangerous modes and revealed a tolerable beam energy spread induced by HOMs. This method allows us to distinguish all dangerous modes of our interest for implementing the necessary damping mechanisms., Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK

The iPipe project consists in the instrumentation, with Fiber Bragg Grating sensors (FBGs), of the beam pipe of the CMS experiment, which is part of the LHC. Being spectrally encoded, the FBGs are not sensitive to electromagnetic interference and broadband-radiation-induced losses. These characteristics allow to realize long distance punctual sensing systems, capable to operate in harsh environments like the underground experimental and accelerator facilities at CERN. The iPipe secures the measurement of any deformation induced on the central beam pipe by any motion in the CMS detector due to element displacement or to magnetic field induced deformations. Moreover, the iPipe FBG temperature sensors represent a unique solution to monitor the beam pipe thermal behavior during the various operational and maintenance phases. This paper reports the use of the iPipe to measure the beam induced heating on the CMS vacuum chamber throughout 2016 and 2017. A first comparison between the measurements and the heat load predicted from beam induced RF heating due to the coupling impedance of the CMS pipe is also reported., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The ICFA Mini-Workshop on Impedances and Beam Instabilities in Particle Accelerators, was held in Benevento, Italy, from 18 to 22 September, 2017. The rich scientific program of the workshop was defined and shaped by a strongly motivated International Advisory Committee, composed of worldwide experts who actively provided their inputs. The conference venue was the San Vittorino complex, located in the very center of the historical town of Benevento. The workshop was supported and sponsored by the University of Sannio, three ongoing large accelerator projects (High Luminosity LHC, LHC Injectors Upgrade, LHC Collimation), the European network ARIES and the INFN section of Naples. Moreover, it was held under the auspices of the Italian Physical Society (SIF). The main goal was to summon the accelerator community actively working in the field of impedances and beam instabilities, and discuss together recent advancements and breakthroughs while defining future directions. Eighty-four participants from different laboratories all around the world attended the workshop, with a strong representation of young accelerator physicists with little experience and plenty of enthusiasm. That's why all the speakers made their best effort to provide a solid educational background into their subjects, before highlighting novelties, challenges and open questions. The workshop chairs also had the great pleasure to celebrate Prof. Vittorio G. Vaccaro on the occasion of the 50 years since the birth of the concepts of beam coupling impedance and stability charts, to which he gave fundamental contributions unanimously recognised by the whole community. The workshop also provided the opportunity to remember dearly Dr. Francesco Ruggiero, who passed away 10 years ago, by highlighting in the opening speech his amazing foresight into all the beam dynamics issues of LHC and all future machines.

Electron cloud has a ubiquitous effect in positively charged particle accelerators and has been observed to induce unwanted detrimental effects on beam quality, sta- bility, vacuum etc. A great effort has been recently devoted to the search of new material morphology and/or coatings which can intrinsically mitigate beam instabilities deriving from electron cloud effects. In this context, we present some characterization of commercially available Cu foams and their qualification mainly in terms of secondary elec- tron yield (SEY), along with the vacuum behavior, their impact on the impedance budget, photo-desorption yield, etc. More experimental efforts are required to finally qual- ify foams as a mature technology to be integrated into accelerator systems. Our preliminary results suggest po- tentially interesting use in the accelerator technology.

Electron cloud is an ubiquitous effect in positively charged particle accelerators and has been observed to induce unwanted detrimental impacts on beam quality, stability, vacuum etc. A great effort has been recently devoted to the search of new material morphology and/or coatings which can intrinsically mitigate beam instabilities deriving from electron cloud effects. In this context, we present some characterization of Cu foams, available from the market, and their qualification in terms of their vacuum behavior, impedance, secondary electron yield, gas desorption etc. More experimental effort is required to finally qualify foams as a mature technology to be integrated in accelerator environments. But, our preliminary results suggests that, when compatible with geometrical constrains, Cu foams can be utilized when low desorption yields are required and as e-cloud moderator in future particles accelerators., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

In this work, we propose to design a liquid crystal–based modular and extendable platform of cutting-edge optical technologies for studying materials based on the analysis of polarization and wavefront of light in the wavelength range of 10–50 μm, which is considered to work even in the longer wavelengths range. This platform will be driven by the future THz-FEL source TerRa@BriXSinO that produces high power radiation in THz-range from 6 THz up to 30 THz (Mid-/Far-IR). The lack of optical infrastructures in this range has been tackled by fabricating liquid crystal–based geometric phase components that have been specifically designed for this purpose. This is in order to optimally exploit all the source’s potential for maximum accuracy and efficiency in determining polarization- and wavefront-sensitive properties of materials. We present an overview of a few experiments for characterizing bulk inhomogeneities, dielectric anisotropy, surface roughness, cracks, impact damages, and stress and strain effects with special emphasis on non-destructive tests on composite structures. The tools for wavefront shaping developed within our platform will be exploited to add a further degree of freedom, i.e., orbital angular momentum, to nonlinear optics techniques, such as Terahertz Hyper-Raman spectroscopy, for investigating chiral agents’ properties.

The paper analyses the phenomenon of gender discrimination in the Hard Sciences Sector. Our purpose is to discover more hidden dimensions of the discrimination phenomenon, such as the implementation of organizational models, the time management, the productivity indicators, which all refer to men workers. The sample used is the universe of INFN (National Institute for Nuclear Physics) in Naples, a sector of “Hard Sciences” (Physics, Astrophysics, etc...) always known for its strong segregation, both horizontal and vertical (we refer to the underrepresentation of women in the sector and /or in top positions). We used the narrative interviews and the functional analysis to study the characteristics of the workers inside INFN. We interviewed some of the employees at INFN in Naples: researchers, technologists, administrative staff and technicians. The results show that the models adopted inside the organization penalize women and often men too: they affect not so much the conventional discrimination indicators (kind of occupation, wages, tasks to be carried out and so on), but the quality of life of the workers (especially the women); these models find their origin in the way the society and the labor market are structured (e.g. the asymmetry of familiar and house tasks).

In many resonant structures the damping of parasitic or higher order modes is indispensable to guarantee a correct and stable performance. This is particularly true in the microwave region in case of cavities or other resonant systems operating in accelerating structures, where the mitigation of spurious resonance effects is mandatory to achieve high quality particle beams. We present the results on the mode suppression in a real pillbox cavity by inserting a properly designed pyramidal metamaterial that acts as light, small volume damper for specific resonances in the range 3–4 GHz, only slightly perturbing other intrinsic modes. Measurements of the cavity response without and with the metamaterial absorber are presented and compared with full wave simulations. Field distribution for the pillbox intrinsic modes under scrutiny is also presented, showing that damping induced by the metamaterial critically depends on its relative position inside the cavity.

Resistive-wall impedance constitutes a significant percentage of the total beam-coupling impedance budget of an accelerator. A number of different reduction techniques have been proposed during the years depending on the specific applications, ranging from higher order modes damping to solutions entailing high electrical-conductivity coatings of the pipe. This article investigates the use of metamaterial-based absorbers for sensibly reducing or nearly canceling the beam-coupling impedance. We design and fabricate subwavelength 2-D metallic resonant structures based on the split-ring resonator (SRR) geometry that can be employed as mode dampers in accelerating structures. A number of prototypes have been fabricated and measured in a “test model” pillbox cavity. Experimental results, combined with full-wave electromagnetic simulations, prove the efficiency of the SRR-based metamaterials. This article opens up to the possibility of considering metamaterials as a valid alternative to other devices for impedance mitigation in experimental setups commonly operating along a particle beamline, such as accelerating cavities or collimators, and more in general for the development of filters with a large out-of-band signal rejection in specific applications.

Il volume è un contributo originale al dibattito sugli interventi a favore della parità di genere nell’Università e nella ricerca. Presenta i risultati della ricerca-azione condotta, insieme alla sperimentazione del programma pilota di mentoring, nell’ambito del progetto europeo GENOVATE@UNINA. Ponendosi in interlocuzione con le ricerche europee più recenti - sviluppate entro la cornice culturale e il quadro di riferimento degli interventi per il cambiamento strutturale, promossi anche attraverso il settimo programma quadro e Horizon 2020 - assume, come quadro di riferimento interpretativo, i processi di cambiamento globale che investono la regolazione del sistema scientifico-accademico. La trattazione si sviluppa seguendo un percorso lineare, che dal dibattito sulle politiche per la parità di genere conduce al disegno dello schema pilota di mentoring (il primo esclusivamente al femminile, nell’università italiana) e, quindi, alla ricerca che ha accompagnato il progetto nel suo percorso. L’interpretazione dei risultati, sorretta da interviste biografico-narrative sui percorsi di carriera e da focus group con mentori e mentee, rivela attraverso quali pratiche e quali processi si producono e riproducono le diseguaglianze di genere nell’accademia e nella ricerca. Con gli strumenti dell’indagine valutativa, questi risultati sono quindi messi a fuoco per ricostruire il funzionamento del mentoring come pratica di genere capace di de-costruire i processi che producono diseguaglianza e produrre effetti trasformativi del contesto scientifico-accademico.

Questo lavoro di ricerca raccoglie e analizza alcuni dati relativi alla presenza delle donne nelle facoltà scientifiche nel corso dell'ultimo decennio. Si tratta di un percorso di analisi intrapreso dal Coordinamento napoletano “Donne nella Scienza” e motivato dalla convinzione che una conoscenza quantitativa e puntuale dei rapporti di genere su scala locale sia un prerequisito indispensabile per proporre azioni positive volte ad incidere sul contesto in cui si opera. In questa comunicazione vengono presentati i dati relativi alla composizione di genere nell’ambito della formazione universitaria e della carriera accademica nelle discipline scientifiche dell’Università “Federico II” di Napoli – che, essendo il più grande ateneo del Sud Italia, risulta altamente rappresentativo della realtà accademica meridionale - nonché del Politecnico e dell'Università di Torino che, insieme, costituiscono uno dei più grandi centri universitari del Nord. L'obiettivo della presente analisi è quello di individuare la collocazione temporale del punto di divergenza della forbice che differenzia il percorso femminile da quello maschile, le differenze tra settori scientifici diversi, le eventuali peculiarità rispetto all'andamento nazionale ed europeo, le specificità geografiche e le differenze tra grandi atenei del Nord e del Sud.