arXiv subjects

Mauro Migliorati

Publications and source records attributed to Mauro Migliorati.

At least 19 recordsLinked to original sources

arXiv2026

Updates on Impedance Studies for the FCC-ee High Energy Booster

Following the Future Circular Collider (FCC) Feasibility Study completion, the impedance model for the FCC-ee High-Energy Booster (HEB) has been significantly expanded beyond the initial copper vacuum pipe resistive wall analysis. This paper presents a comprehensive impedance and wake budget incorporating RF cavities, bellows, and beam position monitors, evaluated through 3D electromagnetic simulations and analytical methods. The updated model provides the basis for future beam dynamics studies, including transverse coupled bunch instability analyses and single bunch tracking simulations. The present work focuses on the construction and comparison of the main impedance and wake contributions, identifying the dominant sources and the components requiring further investigation. These results will be used to refine the HEB collective effects studies and to support future assessments of instability margins and mitigation requirements.

physics.acc-ph↗

arXiv2025

Advancing Atmospheric Pollution Monitoring with Airborne THz Spectrometer

This study details the development and validation of an airborne THz spectrometer designed for real-time, remote detection of atmospheric pollutants. The platform couples a stabilized unmanned aerial system (UAS) with a high-resolution terahertz continuous-wave (THz-CW) laser source and detector, enabling flexible, in situ spectroscopic analysis of dispersed atmospheric vapours. This proof-of-concept investigation confirms the feasibility of UAS-THz-CW systems for spatially resolved environmental pollutant monitoring. The demonstrated capability of this terahertz sensor for remote, multi-component detection of atmospheric contaminants holds significant potential for advancing air pollutant monitoring technologies, providing a pathway for more effective and portable detection. This advancement can contribute to the necessary alert actions for minimizing contaminants impacting public and environmental health, thereby safeguarding human and ecosystem health.

physics.app-ph↗

arXiv2025

Terahertz prototype for air pollutants detection

In this work, we propose a prototype set-up exploiting terahertz time-domain spectroscopy (THz-TDS) to investigate gaseous compounds. The system is portable and allows to perform remote measurements. We used the prototype to characterise for the first time in literature over a broad THz range, pure dichloromethane and chloroform, two pollutants known as very short-lived substances (VSLS) that strongly contribute to ozone depletion. The THz range allows selectively detecting their absorption lines related to the rotational molecular motion for which we also present the theoretical confirmation. Then, we investigate the optical response of a multi-component mixture achieved with the two aforementioned chlorine-based compounds mixed with two widely distributed volatile pollutants (acetone and methanol). For these first measurements, we developed the set-up specifically for laboratory condition in which the substances are directly injected into the gas-cell circuit. Finally, we modified the prototype to ensure that the ambient atmosphere is drawn directly into the gas cell via a long pipe and a suction system opportunely developed. The analysis of the mixtures in both laboratory and in-field conditions demonstrates that the prototype together with the approach employed in this work can simultaneously identify and quantify single components in the atmosphere. The results obtained open up new possibilities for the development and applications of an efficient portable THz-based sensor for the remote detection of multi-component environmental contaminants.

physics.app-ph↗

arXiv2025

Deciphering hidden layers images through terahertz spectral fingerprints

Terahertz radiation enables non destructive, depthresolved analysis of layered artworks. This study demonstrates THz multispectral imaging ability to reveal concealed text beneath mockup of pictorial layers, reconstructing hidden narratives at varying depths through frequency domain analysis.Simultaneously, it maps pigment composition, providing valuable chemical information. Showcasing the power to penetrate and decipher stratified materials, this work establishes THz multispectral imaging as a crucial tool for unlocking hidden secrets and characterizing materials in Cultural Heritage artifacts.

physics.optics↗

arXiv2025

Space Charge in Circular Machines

Space charge forces, which arise directly from the beam's charge distribution and include the influence of image charges and currents induced by interactions with a perfectly conducting, smooth pipe, are very important in high-intensity, low-energy accelerators. These forces play a key role under various beam dynamics regimes, leading to effects such as energy spread, modifications of betatron tunes, and potential instabilities. This lecture will explore the fundamental characteristics of space charge effects in circular accelerators.

physics.acc-ph↗

arXiv2025

Instabilities in Linear Accelerators

As a charged particle beam moves through perfectly conducting structures with varying cross-sectional boundaries - such as RF cavities, tapers, bellows, kickers, ... - it induces both longitudinal and transverse electromagnetic fields called wakefields. In this lecture, we explore the fundamental characteristics of wakefields and illustrate key concepts using simple cases in cylindrical geometry, including a perfectly conducting pipe and the resonant modes of an RF cavity. Finally, we examine how wakefields influence beam dynamics in a LINAC, focusing on beam breakup instabilities and potential mitigation strategies.

physics.acc-ph↗

arXiv2025

Post Long Shutdown 2 CERN Proton Synchrotron Transverse Impedance Model: Description and Beam-Based Validation

In the framework of the LHC Injectors Upgrade project, the CERN Proton Synchrotron underwent hardware changes during the Long Shutdown 2. These changes required an update of the CERN Proton Synchrotron impedance model and an assessment of their impact on beam quality. In the following, the updated CERN Proton Synchrotron impedance model is presented and then validated with beam-based measurements, comparing impedance-induced tune shifts and instability growth rates with simulations performed with a macroparticle tracking code, PyHEADTAIL, which includes the effects of beam-coupling impedance, betatron motion, non-linear synchrotron motion, and space charge. The interplay between first and second-order chromaticity, space-charge forces, and their effect on beam observables is thus studied in detail. Their respective impacts have been assessed and benchmarked with measurements to validate the PS transverse impedance model.

physics.acc-ph↗

arXiv2025

Numerical and Analytical Study of the Magnetic Field Distribution in a Three-Solenoid System

This paper investigates the magnetic fields produced by a three-coil system, focusing on how different mesh resolutions affect the accuracy of the results. Using both the Poisson solver, as well as a numerical approach based on the solution of fractional integrals, the study examines coils with dimensions of 80 mm by 160 mm and a radius of 15.5 mm, each carrying a current of 200 A. The research explores how varying mesh step sizes within the coil regions influences the simulations accuracy and convergence. The results are analyzed along a line parallel to the central axis at a distance equal to half of the solenoid's radius.. The findings emphasize the consistency of the numerical results, the compatibility of the solvers, and offer insights into further optimization strategies for more efficient simulations.

physics.acc-ph↗

arXiv2023

Wakefields of the FCC-ee collimation system

The purpose of this paper is to calculate the longitudinal and transverse wakefields of the FCC collimators by using the electromagnetic codes ECHO3D and IW2D. We cross-checked our results using CST particle studio for long bunches, and found them to be in good agreement. The obtained results show that the collimators give one of the highest contributions to the overall FCC-ee wake potentials. Using the code PyHEADTAIL, we have found that the presence of the geometric wakefield of the collimators leads to the occurrence of transverse mode coupling instability (TMCI) at a significantly lower bunch population as compared to that of all other contributions and solutions to reduce this geometric term must be found.

physics.acc-ph↗

arXiv2023

Optics design and correction challenges for the high energy booster of FCC-ee

One of the major upcoming challenges in particle physics is achieving precise measurements of the Z, W, and H bosons, as well as the top quark. To meet these targets, the next e\textsuperscript{+}e\textsuperscript{-} collider complex, FCC-ee, will need to achieve unprecedented luminosities. The FCC-IS European Study is investigating the feasibility of these challenges, with a cornerstone of the study being the design and optimization of the high-energy booster (HEB). This paper provides an update on the status of the HEB of FCC-ee in light of recent developments in the injector and collider survey, as well as an overview of ongoing work on longitudinal stability and design robustness in relation to field, alignment, and diagnostics errors. Constraints and effects related to the design frequency of the accelerating cavities, as well as collective effects, are also highlighted. Lastly, the paper presents an investigation into an alternative arcs cell design.

physics.acc-ph↗

arXiv2023

A Novel Exact Analytical Expression for the Magnetic Field of a Solenoid

In this paper we present the analytical calculations to derive the magnetic field of a solenoid by solving exactly a fractional integral with the use of a novel method. Starting from the Biot-Savart law, we consider a coil of negligible thickness with a stationary electric current. We derive the expressions of the on and off-axes magnetic field components. The results have been compared to some simplified and known analytical formulae as well as to a commercial numerical code showing a good agreement.

physics.acc-ph↗

arXiv2022

Theory of Diffraction by Holes of Arbitrary Sizes

New high-gradient accelerating RF cavities are nowadays developed in several national laboratories for high-energy physics applications. Ultra high gradients, up to the order of GV/m, can be achieved by using ultra compact accelerating structures in the sub-THz regime. Nevertheless, the experimental setup for measuring the main RF parameters for such compact structures is not trivial and can easily produce errors due to lack of accuracy. Moreover, Radio-Frequency (RF) simulations for these types of cavities can require a large amount of computational time. In particular, one of the main RF parameters that needs to be evaluated and measured for the accelerating structures is the reflection coefficient. In order to obtain a fast and accurate analytical estimation, we have developed the electromagnetic theory for the calculation of the coupling of a resonant cavity with an RF waveguide. This theory is based on the Bethe's small aperture polarization approach, also developed by Collin's. In this paper, we give an exact analytical expression of the reflection coefficient as function of the physics parameters of the cavity-waveguide system, which can be applied to any geometry, material and frequency.

physics.acc-ph↗

arXiv2021

A hard open X-band RF accelerating structure made by two halves

High-gradient linacs of next generation require novel accelerating structures which are compact, robust and cost-effective. Dedicated research and development have been launched in the linear-collider community. This paper focuses on the technological developments directed to show the viability of novel welding techniques and related applications, in order to benefit from the superior high-gradient performance of accelerating structures made of hard-copper alloys. The structure geometry that we propose allows getting a high longitudinal shunt impedance of the accelerating mode and increasing the mode separation frequencies.

physics.acc-ph↗

arXiv2021

Challenges for the interaction region design of the Future Circular Collider FCC-ee

The FCC-ee is a proposed future high-energy, high-intensity and high-precision lepton collider. Here, we present the latest development for the FCC-ee interaction regions, which shall ensure optimum conditions for the particle physics experiments. We discuss measures of background reduction and a revised interaction region layout including a low impedance compact beam chamber design. We also discuss the possible impact of the radiation generated in the interaction region including beamstrahlung.

physics.acc-ph↗

arXiv2021

Ultra-Compact Ka-band linearizer for the Ultra-Compact X-Ray Free-Electron Laser at UCLA

Notably innovative technologies will permit compact and affordable advanced accelerators as the linear collider and X-ray free-electron lasers (XFELs) with accelerating gradients over twice the value achieved with current technologies. In particular XFEL is able to produce coherent X-ray pulses with peak brightness 10 orders of magnitude greater than preceding approaches, which has revolutionized numerous fields through imaging of the nanoscopic world at the time and length scale of atom-based systems, that is of femtosecond and Angstrom. There is a strong interest for combining these two fields, to form a proper tool with the goal of producing a very compact XFEL in order to investigate multi-disciplinary researches in chemistry, biology, materials science, medicine and physics. In the framework of the Ultra -Compact XFEL project (UC-XFEL) under study at the UCLA, an ultra high gradient higher harmonic RF accelerating structure for the longitudinal space phase linearization is foreseen. To this aim, a Ka-Band linearizer (34.2 GHz) with an integrated voltage of at least 15 MV working on 6th harmonic with respect to the main Linac frequency (5.712 GHz) is required. We here present the electromagnetic design of a cold ultra compact Ka-band SW linearizer, 8 cm long, working on pi mode with an ultra high accelerating gradient (beyond 100 MV/m) and minimum surface electric field for minimizing the probability of RF breakdown. Moreover, we discuss a TW option and compare it with the initial SW structure, by means of main RF parameters as well as beam-dynamics considerations. The numerical electromagnetic studies have been performed by using the well known SuperFish, HFSS and CST.

physics.acc-ph↗

arXiv2020

Fractional Powers of the Differentiation and Integration Operators and its Application in Accelerator Physics and Technology

In this paper we present a solution to a fractional integral of the order 3/2 with the use of a novel method. The integral arises during solving the Biot-Savart equation to find the exact analytical solution for the magnetic field components of a solenoid. We solved the integral by cutting the branch line in order to have an analytic function inside the integral instead of multi-valued operation.

math.CA↗

arXiv2020

A SW Ka-Band Linearizer Structure with Minimum Surface Electric Field for the Compact Light XLS Project

There is a strong demand for accelerating structures able to achieve higher gradients and more compact dimensions for the next generation of linear accelerators for research, industrial and medical applications. In the framework of the Compact Light XLS project, an ultra high gradient higher harmonic RF accelerating structure is needed for the linearization of the longitudinal space phase. In order to determine the maximum sustainable gradients in normal conducting RF powered particle beam accelerators with extremely low probability of RF breakdown, investigations are in progress for using shorts accelerating structures in the Ka-band regime. We here report an electromagnetic design of a compact linearizer standing wave (SW) accelerating structure 8 cm long operating on $π$ mode, third harmonic with respect to the Linac frequency (11.994 GHz) with a 100 MV/m accelerating gradient and minimum surface electric field. Numerical electromagnetic studies have been performed by using the well known SuperFish, HFSS and CST computing software.

physics.acc-ph↗

arXiv2018

Study of Collective Effects in the FCC-ee Collider

The Future Circular Collider (FCC) study aims at designing different options of a post-LHC collider. The high luminosity electron-positron collider FCC-ee based on the crab waist concept is considered as an intermediate step on the way towards FCC-hh, a 100 TeV hadron collider using the same tunnel of about 100 km. Due to a high intensity of circulating beams the impact of collective effects on FCC-ee performance has to be carefully analyzed. In this paper we evaluate beam coupling impedance of the FCC-ee vacuum chamber, estimate thresholds and rise times of eventual single- and multibunch beam instabilities and discuss possible measures to mitigate them.

physics.acc-ph↗