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In this work, we present numerical results for the electron cloud build-up and mitigation studies considering Arc Dipole and Drift sections of the FCC-ee collider. We report the central electron density that could be reached by minimising secondary electron contributions and the photoelectron generation rates in order to achieve e⁻ densities lower than the single-bunch instability threshold, considering the baseline beam parameters. Additionally, simulation results revealing the behavior of electron-cloud formations for various SEY values, photoemission rates, vacuum chamber radii, and bunch spacings are included. In the last section, we discuss initial investigations to clean residual electrons after the beam pass., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

The current injector complex design of the FCC-e⁺e⁻ project consists of e⁺/e⁻ linacs, which accelerate the beams up to 6 GeV, a damping ring at 1.54 GeV, a pre-booster ring, accelerating the beam up to 16 GeV and a booster synchrotron ring integrated in the collider tunnel accelerating the beams up to the collision energies. The purpose of the damping ring is to accept the 1.54 GeV beam coming from the linac-1, damp the positron/electron beams and provide the required beam characteristics for the injection into the linac-2. In this presentation the current damping ring design is introduced and analytical calculations on various collective effect such as space charge, intra-beam scattering, longitudinal micro-wave instability, transverse mode coupling instability, ion effects, electron cloud and coherent synchrotron radiation, are presented., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The Future Circular electron-positron Collider (FCC-ee) is aimed at studying the Z and W bosons, the Higgs, and top quark with extremely high luminosity and good energy efficiency. Responding to a request from the 2020 Update of the European Strategy for Particle Physics, in 2021 the CERN Council has launched the FCC Feasibility Study to examine the detailed implementation of such a collider. This FCC Feasibility Study will be completed by the end of 2025 and its results be presented to the next Update of the European Strategy for Particle Physics expected in 2026/27., Proceedings of the 5th North American Particle Accelerator Conference, NAPAC2022, Albuquerque, NM, USA

The main challenges for far-future higher-energy particle colliders are discussed along with possible technological paths to overcome them. This workshop paper is mostly an abbreviated version of an article published in the ’’Frontiers in Physics’’ journal (under the Creative Commons Attribution 4.0 International licence). The topic of electric power generation using accelerators has been added., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

The Future Circular electron-positron Collider (FCC-ee) is designed for high precision particle physics experiments. This demands a precise knowledge of the beam energies, obtained by resonant depolarization, and from which the center-of-mass energy and possible boosts at all interaction points are then determined. At the highest beam energy mode of 182.5 GeV, the energy loss due to synchrotron radiation is about 10 GeV per revolution. Hence, not only the location of the RF cavities, but also a precise control of the optics and understanding of beam dynamics, are crucial. In the studies presented here, different possible locations of the RF-cavities are considered, when calculating the beam energies over the machine circumference, including energy losses from crossing angles, a non-homogeneous dipole distribution, and an estimate of the beamstrahlung effect at the collision point., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

Within the framework of the Future Circular Collider Feasibility and Design Study, the design of the electron-positron collider FCC-ee is being optimised, as a possible future double collider ring, currently foreseen to start operation during the 2040s. FCC-ee is designed to operate at four different energy stages, allowing for precision measurements: from the Z-pole up to above the ttbar-threshold. This synchrotron with almost 100 km circumference is designed including advanced accelerator concepts, such as the crab-waist collision scheme or one combined off-momentum and betatron collimation insertion. Furthermore, numerous optics tuning and measurement studies are being performed to drive the collider design at an early stage and guarantee its feasibility and efficient operation., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

A special session at eeFACT’22 reviewed the electrical power budgets and luminosity risks for eight proposed future Higgs and electroweak factories (CCC, CEPC, CERC, CLIC, FCC-ee, HELEN, ILC, and RELIC) and, in comparison, for a lepton-hadron collider (EIC) presently under construction. We report highlights of presentations and discussions., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

The Future Circular Collider (FCC) ’’integrated programme’’ consists of a proposed high-luminosity e⁺e⁻ collider, FCC-ee, serving as Higgs and electroweak factory, which would, in a second stage, be succeeded by a 100 TeV hadron collider, FCC-hh. FCC-ee and FCC-hh share the same 91 km tunnel and technical infrastructure. In summer 2021 a detailed FCC Feasibility Study (FCC FC), focused on siting, tunnel construction, environmental impact, financing, operational organisation, etc., was launched by the CERN Council. This FCC Feasibility Study (FCC FS) should provide the necessary input to the next European Strategy Update expected in 2026/27. In this paper we briefly review the FCC key design features, status and plans. This paper is an updated, slightly modified version of an article submitted to the proceedings of NA-PAC’22 (published under the Creative Commons Attribution 3.0 license). Sections on two planned accelerator mock-ups and on regional activities were taken from an article in the ECFA Newsletter., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

The international FCC study group published in 2019 a Conceptual Design Report for an electron-positron collider with a centre-of-mass energy from 90 to 365 GeV with a beam currents of up to 1.4 A per beam. The high beam current of this collider create challenging requirements on the injection chain and all aspects of the linac need to be carefully reconsidered and revisited, including the injection time structure. The entire beam dynamics studies for the full linac, damping ring and transfer lines are major activities of the injector complex design. A key point is that any increase of positron production and capture efficiency reduces the cost and complexity of the driver linac, the heat and radiation load of the converter system, and increases the operational margin. In this paper we will give an overview of the status of the injector complex design and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration. In this framework, furthermore, we also present the preliminary studies of the FCC-ee positron source highlighting the main requirements and constraints., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The design parameters of the FCC-ee foresee operation with a total stored beam energy of about 20 MJ, exceeding those of previous lepton colliders by almost two orders of magnitude. Given the inherent damage potential, a halo collimation system is studied to protect the machine hardware, in particular superconducting equipment such as the final focus quadrupoles, from sudden beam loss. The different constraints that led to dedicating one straight section to collimation will be outlined. In addition, a preliminary layout and optics for a collimation insertion are presented., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

In order to maximize the luminosity production time in the FCC-ee, top-up injection will be employed. The positron and electron beams will be accelerated to the collision energy in the booster ring before being injected with either a small transverse or longitudinal separation to the stored beam. Using this scheme essentially keeps the beam current constant and, apart from a brief period during the injection process, collision data can be continuously acquired. Two top-up injection schemes, each with on- and off-momentum sub-schemes, viable for FCC-ee have been identified in the past and are studied in further detail to find a suitable design for each of the four operation modes of the FCC-ee. In this paper, injection straight optics, initial injection tracking studies and the effect on the stored beam are presented. Additionally, a basic proxy error lattice is introduced as a first step to studying injection into an imperfect machine., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

Within the framework of the Future Circular Collider Feasibility Study, the design of the electron-positron collider FCC-ee is optimised, as a possible future double collider ring, currently foreseen to start operation during the 2040s. With close to 100 km of circumference and strong synchrotron radiation damping at highest beam energy, adequate beam measurements are needed to control the optics at the desired level. Various possible techniques to measure the optics in FCC-ee are explored, including the option of turn-by-turn measurements in combination with an AC-dipole., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The LEMMA-type muon collider generates muon pairs by the annihilation of 45 GeV positrons with electrons at rest. Due to the small cross section, an extremely high rate of positrons is required, which could be achieved by a ’Gamma factory’ based on the LHC. Other challenges with the LEMMA-type muon production scheme include the emittance preservation of muons and muon-generating positrons upon multiple traversals through a target, and the merging of many separate muon bunchlets. These two challenges may potentially be overcome by (1) operating the FCC-ee booster with a barrier bucket and induction acceleration, so that all positrons of a production cycle are merged into one single superbunch instead of storing ~10,000 separate bunches; and (2) sending the positron superbunch into a plasma target. During the passage of the positron superbunch, the electron density is enhanced 100–1000 fold without any increase in the density of nuclei, so that beamstrahlung and Coulomb scattering are essentially absent. We investigate prospects and difficulties of this approach, including emittance growth due to filamentation in the nonlinear plasma channel and due to positron self-modulation., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

Since the Higgs boson discovery at CERN, precision measurement of its properties has become the first priority in the field of High Energy Physics. Two laboratories, CERN from Europe and IHEP from China, have proposed large scale circular electron-positron colliders, namely FCC-ee and CEPC. Record luminosities are expected in the center of mass energy range from 90 to about 365 GeV. In this talk the statuses of both projects are reviewed: Following the publication of the first CDR FCC-ee and CEPC entering the phase of consolidation and feasibility study. Special focus will be put on R plans, prototyping and key technologies., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The FCC-e⁺e⁻ injector complex needs to produce and to transport high-intensity e⁺ and e⁻ beams at a fast repetition rate for topping up the collider at its collision energy. Two different options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: either using the existing SPS machine or designing a completely new ring. The purpose of this paper is to present the studies of collective effects with analytical estimates for both the pre-booster ring design options including space charge (SC), longitudinal micro-wave instability (LMI), transverse mode coupling instability (TMCI), ion effects, electron cloud (e-cloud), coherent synchrotron radiation (CSR), and intra-beam scattering (IBS)., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

Improving the accuracy of the impedance model of an accelerator is important for keeping beam instabilities and power loss under control. Here, by means of the PyHEAD- TAIL tracking code, we first review the longitudinal mi- crowave instability threshold for FCC-ee by taking into ac- count the longitudinal impedance model evaluated so far. Moreover, we present the results of beam dynamics simula- tions, including both the longitudinal and transverse wake- fields due to the resistive wall, in order to evaluate the influ- ence of the bunch length on the transverse mode coupling instability. The results of the transverse beam dynamics are also compared with the Vlasov solver DELPHI., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The FCC-ee is a proposed future high-energy, high-intensity and high precision lepton collider. Here, we present the latest developments 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., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The FCC-ee project studies the design of a future 100 km e+/e circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm⁻² s⁻¹. To achieve ultra-low vertical emittance a highly effective emittance tuning scheme is required. In this paper, we describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

Various physical and technology-dependent limits are encountered for key performance parameters of accelerators such as high-gradient acceleration, high-field bending, beam size, beam brightness, beam intensity and luminosity. This paper will review these limits and the associated challenges. Possible figures-of-merit and pathways to ultimate colliders will also be explored., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

At the end of 2018, a large worldwide collaboration, with contributors from more than 350 institutes completed the conceptual design of the Future Circular Collider (FCC), a ~100 km accelerator infrastructure linked to the existing CERN complex, that would open up the way to the post-LHC era in particle physics. We present an overview of the two main accelerator options considered in the design study, namely the lepton collider (FCC-ee), serving as highest-luminosity Higgs and electroweak factory, and the 100-TeV energy-frontier hadron collider (FCC-hh), along with the ongoing technological R efforts and the planned next steps. A recently approved EU co-funded project, the FCC Innovation Study (FCCIS), will refine the design of the lepton collider and prepare the actual implementation of the FCC, in collaboration with European and global partners, and with the local authorities., Proceedings of the 11th International Particle Accelerator Conference, IPAC2020, Caen, France

This document discusses the machine parameters and expected luminosity performance for the proposed future circular lepton collider FCC-ee. Particular emphasis is put on availability, physics run time, and efficiency. Key performance assumptions are compared with the operational experience of several past and present colliders including their injectors - LHC, LEP/LEP-2, PEP-II, KEKB, BEPCII, DAΦNE, SLC and the SPS complex., Proceedings of the 62th ICFA ABDW on High Luminosity Circular e$^+$e$^-$ Colliders, eeFACT2018, Hong Kong, China

As part of the Future Circular Collider study, the High Energy LHC (HE-LHC) is a proposed hadron collider situated in the already existing LHC tunnel. It aims at achieving a center of mass energy of 27 TeV, almost doubling the design c.o.m. energy of the LHC. This increase in energy relies on the use of 16 T Nb₃Sn dipoles to be developed for the FCC-hh. The field quality of these dipoles is expected to have a big impact on the Dynamic Aperture (DA) at injection energy and subsequently tracking studies are conducted to evaluate the impact of magnetic field errors on the beam dynamics. In the following the results of these studies for the different injection energies considered for the HE-LHC are presented and a possible strategy for increasing the DA are discussed., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

The 100 km FCC-ee e⁺/e⁻ circular collider requires luminosities in the order of 10³⁵ cm⁻² s⁻¹ and very low emittances of 0.27 nm·prad for the horizontal plane and 1 pm·prad in the vertical. In order to reach these requirements, extreme focusing of the beam is needed in the interaction regions, leading to a vertical beta function of 0.8 mm at the IP. These challenges make the FCC-ee design particularly susceptible to misalignment and field errors. This paper describes the tolerance of the machine to magnet alignment errors and the effectiveness of optics and orbit correction methods that were implemented in order to bring the vertical dispersion to acceptable values, which in turn limits the vertical emittance. Thousands of misalignment and error seeds were introduced in MADX simulations and a comprehensive correction strategy, which includes macros based upon Dispersion Free Steering (DFS), linear coupling correction based on Resonant Driving Terms (RDTs) and response matrices, was implemented. The results are summarized in this paper., Proceedings of the 62th ICFA ABDW on High Luminosity Circular e$^+$e$^-$ Colliders, eeFACT2018, Hong Kong, China

The High Energy Large Hadron Collider (HE-LHC), a possible successor of the High Luminosity Large Hadron Collider (HL-LHC) aims at reaching a centre-of-mass energy of about 27 TeV using basically the same 16 T dipoles as for the hadron-hadron Future Circular Collider FCC-hh. Designing the HE-LHC results in a trade off between energy reach, beam stay clear as well as geometry offset with respect to the LHC. In order to best meet the requirements, various arc cell and dispersion suppressor options have been generated and analysed, before concluding on two baseline options, which are presented in this paper. Merits of each design are highlighted and possible solutions for beam stay clear minima are presented., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

In recent years, three schemes for producing low-emittance muon beams have been proposed: (1) e⁺e⁻ annihilation above threshold using a positron storage ring with a thin target [M. Boscolo, P. Raimondi et al.], (2) laser/FEL-Compton back-scattering off high-energy proton beams circulating in the LHC or FCC-hh [L. Serafini et al.], (3) the Gamma factory concept, where partially stripped heavy ions collide with a laser pulse to directly generating muons [W. Krasny]. The Gamma factory would also generate copious amounts of positrons which could in turn be used as source for option (1). On the other hand the top-up booster of the FCC-ee design would be an outstanding e⁺ storage ring, at the right beam energy, around 45 GeV. After rapid acceleration the muons, produced in one of the three ways, could be collided in machines like the SPS, LHC or FCC-hh. Possible collider layouts are suggested., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The international Future Circular Collider study, launched in 2014, is finalizing a multi-volume conceptual design report. The FCC develops high-energy circular collider options based on a new 100 km tunnel. Long-term goal is a 100 TeV proton-proton collider (FCC-hh). The study also includes a high-luminosity electron-positron collider (FCC-ee), and it also examines lepton-hadron scenarios (FCC-he). Civil engineering and technical infrastructure studies were carried out. Global programs advance the development of high-field superconducting magnet technology based on Nb3Sn, the optimization of a suitable large superconducting RF system, and schemes for synchrotron radiation handling. In addition, the FCC study includes the design of the HE-LHC, housed in the LHC tunnel, and based on the same high-field magnet technology as the FCC-hh. The FCC study further includes an elaboration of the physics cases, including for heavy-ion collisions, and detector concepts, as well as staging and implementation scenarios. The FCC collaboration has grown to more than 120 institutes from 30 countries around the world. This invited talk summarizes the study achievements and the final designs., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The CERN multipurpose Gamma Factory proposal relies on using Partially Stripped Ion (PSI) beams, instead of electron beams, as the drivers of its light source. If such beams could be successfully stored in the LHC ring, fluxes of the order of 10¹⁷ photons/s, in the gamma-ray energy domain between 1 MeV and 400 MeV could be achieved. This energy domain is out of reach for the FEL-based light sources as long as the multi TeV electron beams are not available. The CERN Gamma Factory proposal has the potential of increasing by 7 orders of magnitude the intensity limits of the present Inverse Compton Scattering sources. In 2017 the CERN accelerator complex demonstrated its flexibility by producing a new, xenon, ion beam. The Gamma Factory study group, based on this achievement, requested special studies. Its aim was to inject and to accelerate, in the SPS, partially stripped xenon ions Xe³⁹⁺ measure their life time, and determine the relative strength of the processes responsible for the PSI beam losses. This study, the results of which are presented in this contribution, was an initial step in view of the the future studies programmed for 2018 with lead PSI beams., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The Future Circular e⁺e⁻ Collider (FCC-ee) requires two 180-degree turnaround loops to transport the positron beam from the damping ring to the lower energy section of the linac. In addition bunch compression is required to reduce the RMS bunch length from 5 mm to 0.5 mm, prior to injection into the linac. A dogleg bunch compressor comprised of two triple bend achromat (TBAs) can achieve this compression. Sextupole magnets are incorporated into the bunch compressor design for chromaticity correction as well as optimisation of the second-order longitudinal dispersion, T₅₆₆, and to linearize the longitudinal phase space distribution. In this paper we present the design of the transport line and the bunch compressor. Measures to limit emittance growth due to coherent synchrotron radiation (CSR) are also discussed, because despite the relatively long bunch length, the large degree of bending required introduces cause for consideration of CSR., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The High Energy LHC (HE-LHC) proton-proton collider is a proposed replacement of the LHC in the existing 27-km tunnel, with the goal of reaching the centre-of-mass beam energy of 27 TeV. The required higher dipole field can be realized by using 16-T dipoles being developed for the FCC-hh design. A major concern is the dynamic aperture at injection energy due to degraded field quality of the new dipole based on Nb3Sn superconductor, the potentially large energy swing between injection and collision, and the slightly reduced magnet aperture. Another issue is the field in quadrupoles and sextupoles at top energy, for which it may be cost-effective, wherever possible, to stay with Nb-Ti technology. In this study, we explore design options differed by arc lattice, for three choices of injection energy, with the goal of attaining acceptable magnet field and maximum injection dynamic aperture with dipole non-linear field errors.

The KEK ATF2 facility, with a well instrumented beam line and Final Focus (FF), is a proving ground for linear collider (LC) technology to demonstrate the extreme beam demagnification and spot stability needed for a LC FF*. ATF2 uses water cooled magnets but the baseline ILC calls for a superconducting FF**. Thus we plan to replace some ATF2 FF magnets with superconducting ones made via direct wind construction as planned for the ILC. With no cryogenic supply at ATF2, we look to cool magnets and current leads with a few cryocoolers. ATF2 FF coil winding is underway at BNL and production warm magnetic measurements indicate good field quality. Having FF magnets with larger aperture and better field quality than present FF might allow reducing the beta function at the FF for study of focusing regimes relevant to CLIC. Our ATF2 magnet cryostat will have laser view ports for cold mass movement measurement and FF support and stabilization requirements under study. We plan to make stability measurements at BNL and KEK to relate ATF2 FF magnet performance to that of a full length ILC R prototype at BNL. We want to be able to predict LC FF performance with confidence., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

We study the interaction of macro-particles residing inside the LHC vacuum chamber, e.g. soot or thermal-insulation fragments, with the circulating LHC proton beam. The coupled equations governing the motion and charging rate of metallic or dielectric micron-size macro-particles are solved numerically to determine the time spent by such "dust" particles close to the path of the beam as well as the resulting proton-beam losses, which could lead to a quench of superconducting magnets and, thereby, to a premature beam abort., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

In this paper, we present a lattice design for the Large Hadron Electron Collider (LHeC) recirculating Linac. The recirculating Linac consists of one roughly 3km long linac hosting superconducting RF (SRF) accelerating cavities, two arcs and one transfer line for the recirculation. Electron beam will have two passes in the SRF linac to get a maximum energy of 140 GeV, or have four passes with a maximum energy of 60 GeV (two for acceleration and two for deceleration) in the Energy Recovery Linac (ERL) option., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

The presence of an electron cloud in an accelerator generates a number of interesting phenomena. In addition to electron-driven beam instabilities, the electron "pinch" occurring during a beam-bunch passage gives rise to a highly nonlinear force experienced by individual beam particles. A simple 1-dimensional model for the effect of the electron pinch on the beam reveals a surprisingly rich dynamics. We present the model and discuss simulation results., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

In a linac-ring electron-proton collider based on the LHC, before and after the collision point the electron beam can be deflected with weak dipole magnets positioned in front of the superconducting final quadrupole triplets of the 7-TeV proton beam. Significant synchrotron radiation may be produced when the electron beam, of energy 60-140 GeV, passes through these dipole magnets. As an alternative or complement to shielding, parts of the synchrotron radiation could be extracted together with the electron beam. We propose using mirrors with shallow grazing angle to deflect the synchrotron radiation away from the proton magnets. Various LHeC options are considered. Limitations and challenges of this approach are discussed., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present the summaries of the various workshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cryomodule design, construction, integration, validation, and planning., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

In this paper, we estimate the emittance growth in the LHeC recirculating Linac, the lattice design of which is presented in another paper of IPAC10 proceedings. The possible sources for emittance growth included here are: energy spread from RF acceleration in the SRF (superconducting RF) linac plus large chromatic effects from the lattice, synchrotron radiation (SR) fluctuations in the recirculating arcs. 6-D multi-particle tracking is launched to calculate the emittance from the statistical point of view. The simulation results are also compared with a theoretical estimation., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

In the frame of the FCC study we are designing a 27 TeV hadron collider in the LHC tunnel, called the High Energy LHC (HE-LHC)., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The High Intensity Muon Beams (HIMB) project at the Paul Scherrer Institute (PSI) will provide muon intensities of the order of 1e10 muons/s for particle physics and material science experiments, two orders of magnitude higher than the state of the art, which is currently available also at PSI. In particle transport simulations for the HIMB, we use G4beamline with measured pi+ cross-sections and with variance reduction. We also use the codes COSY INFINITY, TRANSPORT, and TURTLE for some studies. We perform asynchronous Bayesian optimisation of the beamlines on a computing cluster using G4beamline and the optimisation package DeepHyper. We performed numerous studies for the design of the HIMB, and we produced various results, including the muon transmission, beam phase space, polarisation, and momentum spectrum., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

Nb₃Sn, NbTiN and NbN are superconductors with critical temperatures of 18.3, 12.6-17 and 11.6-17.5 K, respectively, these are higher than that of Nb at 9.3 K. Hence, at 4 K, they have an RF resistance, an order of magnitude lower than that of Nb, which leads to quality factors above those of Nb. In recent years, there has been an extensive effort converting Nb cavities into Nb₃Sn. Alloying the top inner layer of the cavity using Sn diffusion at a high temperature has had some degree of success, however, the reproducibility remains a major hindering and limiting factor. In this study, we report on the PVD deposition of NbTiN inside a 6 GHz cavity, using an external magnetic coil configuration. The deposition is done at an elevated temperature of about 650 C. We report on the superconducting properties, film structure and its stoichiometry and surface chemical state. The films have been characterised with SEM, XRD, XPS, EDS and SQUID magnetometer., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

In order to study the remaining open questions concerning CP violation and neutrino mass hierarchy, as well as to search for physics beyond the Standard Model, future experiments require precise measurements of the neutrino interaction cross-sections in the GeV/c regime. The absence of a precise knowledge of the neutrino flux currently limits this measurement to a 10-20% uncertainty level. The ENUBET project is proposing a novel facility, capable of constraining the neutrino flux normalization through the precise monitoring of kaon decay products in an instrumented decay tunnel. The collaboration has conducted numerous studies using a beam-line with a central Kaon momentum of 8.5 GeV/c and a ±10% momentum spread. We present here the design of a new beam-line, broadening the range of Kaons to include momenta of 4, 6, and 8.5 GeV/c, thus allowing ENUBET to explore cross-sections over a much larger energy range. In this contribution, we discuss the status of this design, the optimization studies performed, the early results, and the expected performance in terms of kaon and neutrino rates. We also present the first estimations of the background expected to be seen by the experiment.