A good understanding of radiative Bhabha scattering at high energy e+e- colliders is important as it might become the limiting factor for the beam lifetimes. In this talk, the impact of beam-size effects will be presented, in particular the strong suppression of the radiative Bhabha scattering due to small lateral beam sizes at the interaction points. The resulting beam lifetime limits will be...
The design of the interaction region of the positron-electron future circular collider must comply with various important constraints, imposed by high beam energy, high luminosity, need for polari-zation, and crossing scheme. An overview of the MDI design will be presented with a picture of the recent updates in the layout and ongoing studies. The status of the MDI activity will be summarised...
The Future Circular Collider FCC-ee aims at unprecedented luminosities to be obtained with the crab-waist collision scheme. In this talk we will describe the mechanical model of the interaction region layout including its assembly procedure.
After a discussion on the requirements and constraints, we will present the engineered design of the vacuum chamber with the cooling system, the...
A plethora of measurements at the FCC-ee crucially depend on efficient flavour tagging and precise flight distance measurements. To achieve this, the innermost piece of the FCC-ee detectors, the vertex detector, has to precisely locate the collision vertices, while adding only a minimal amount of material to the detector to limit multiple scattering deteriorating the detector...
The FCC-ee is a high-luminosity circular electron-positron which will have beam energies ranging from 45.6 ($\rm{Z}$ mode) to 182.5 GeV ($\rm{t\bar{t}}$ mode). In this presentation, the synchrotron radiation sources associated to each operating energy are described. The performances of the synchrotron radiation collimation scheme are detailed including the contribution from particles in the...
This presentation provides an update on the results of the socio-economic impact analysis of the FCC-ee infrastructure. It draws from extensive research conducted between March 2020 and April 2023 by a collaboration of economists, data scientists, engineers, and policy analysts. The benefits expected to be generated during the FCC project construction and operation phases are identified and...
This talk will provide an overview of the radiation environment and dose studies for the experimental Interaction Region (IR) of FCC-ee. In particular, first considerations and studies for the photon (Beamstrahlung) dump will be presented.
This talk will present an overview on the beam instrumentation for the FCCee accelerator complex. The specifications and main challenges for the FCCee beam instrumentation will be discussed. A status on the on-going R&D activities will be also reported, together with the plans for future studies.
The inter-beam distance in the collider arcs has recently been increased to accommodate the latest design of the SR absorbers in the dipoles. This has led to a modification of the magnet designs, taking advantage of the larger distance between apertures to try minimizing both the aperture coupling in the quadrupoles, and the saturation in the sextupoles.
The presentation will summarize the...
The FCC-ee HTS4 project studies the possibility of replacing all (warm) short straight sections of FCC-ee with superconducting ones. There are about 2900 short straight sections in the arcs of FCC-ee housing arc quadrupoles, sextupoles and various corrector magnets. In the conceptual design report design, all these magnets are normal-conducting with an important footprint in the overall...
n this talk, we will discuss the critical role of insertion region (IR) tuning tools in the successful simulation and operation of the FCC. Due to the complex design and challenging nature of the FCC, these tools are essential for achieving sufficient luminosity and machine stability. Collaboration with experts in the field is important for designing effective IR tuning tools that meet the...
In this contribution we will give an overview of the pre-injector complex by introducing the baseline and the different options studied in recent months.
The FCC-ee positron source target is the device in charge of generating particles (i.e. positrons) by colliding a high intensity primary electron beam on it, which produces gamma rays and triggers the pair production mechanism.
At a design level, the positron target presents two main challenges: i) a high-energy deposition density due partly to a small incident beam size and ii) the...
The Future Circular Collider project is built around two main pillars: the construction of 100 km lepton collider running at increasing energies from the Z-pole to the t-tbar threshold (FCC-ee) followed by a hadron collider in the same tunnel (FCC-hh) to explore unprecedented energy frontier.
The realization of FCC-ee relies on a very challenging injector complex that should provide the...
This talk will provide an update on the latest civil engineering design of the FCC feasibility study. It will cover a range of topics, including the latest sub-surface structures, the progress of the construction schedule and cost study, and the geotechnical site investigations that will be carried out to assess the feasibility of the project.
A status report of the Compton polarimeter will be provided along with relevant challenges.
The new Future Circular Colliders (FCC), including high-luminosity e⁺e⁻ collider, exploits the crab waist interaction scheme at interaction region (IR) with a beam crossing angle of 30 mrad. The small values of the beta functions at the interaction point requires strong and thin crab sextupole pair for chromaticity correction. Their location between 250 m and 700 m from the interaction region,...
The FCC-ee will implement a crab-waist configuration, implying a very dense Machine Detector Interface (MDI), having accelerator components to be placed inside the detector. For the moment, a very elegant but complex design raises challenges, especially regarding the conditions near the components requiring alignment. Alignment sensors will need to be installed and operate in cryogenic...
This presentation will give an update on the subsurface site investigations planned for 2024 and 2025 in the areas of highest geological uncertainty on the proposed future alignment of the FCC.
Beginning briefly by presenting why having a robust 3D geological subsurface model is essential for civil engineering studies, it will go on to describe the level of detail and certainty in the...
The FCC-ee beam position monitors (BPM) is a non-invasive beam diagnostics system which consists out of ~2000 BPM pickups in each of the two main rings, plus read-out electronics and infrastructure. While most BPM pickups are located in the arcs, rigidly fixed at the quadrupole magnets, 3+3 BPMs are located in each of the interaction regions (IR) with particular challenging real-estate,...
Several linacs will bring the beam energy up to the nominal initial booster energy of 20 GeV. This will be achieved in several sections. The electron linac, from the exit of the gun section at 200 MeV up to 1.54 GeV will increase the bunch energy to 6 GeV, the common linac, where both electrons and positrons will travel, from 1.54 GeV up to 6 GeV, and the high energy linac to the final 20 GeV....
On demand of the Technical and Infrastructure Working Group for Electricity & Energy Management Work Package, the French Transmission System Operator has led a preliminary study of the FCC connexion for electricity supply. The goal of the pre-study is:
- to define how to connect the FCC to the French grid,
- to evaluate the impact on the electric system and on the other users connected to...
Layout and design of positron and electron linacs up to 20 GeV will be presented and discussed including the baseline and alternative options.
Many key measurements at FCC-ee, such as the determination of the W-boson and top-quark mass and widths, require excellent knowledge of the collision energy. Resonant depolarisation, which will be the principal tool for calibration of the beam energy at the Z pole, will be much more demanding in the W+W- regime, and impossible at higher energies. Related challenges exist for the measurement...
With the advent of power electronics in recent years, DC networks have become an interesting solution for the distribution of electrical energy due to their advantages in terms of efficiency, controllability, volume reduction, and integration of energy storage. Considering the particularities of the FCC, DC networks could be used to supply power to specific machine parts.
At a larger scale,...
The study and optimisation of manufacturing processes for copper substrates of Nb-coated cavities is a subject of renewed interest, due to the challenging demands on SRF performance for the Future Circular Collider (FCC).
This contribution will highlight related activities, currently being performed at CERN, namely on the R&D and optimization of welding processes, and on the production of...
Since the publication of the CDR, much progress has been made on the layout of the FCC-hh ring. Driven by the recent result of the ring placement studies and updates of the FCC-ee layout, major changes have been implemented in the FCC-hh ring layout. In this talk, I review the main features of the new layout, and I also provide an outlook of future studies and activities.
The Slotted Waveguide ELLiptical (SWELL) cavity is a novel concept of superconducting cavity proposed as an alternative option for the FCCee RF system. The presentation will give an update on the fabrication of the 1.3 GHz SWELL prototype used as a first step of the feasibility demonstration. The mechanical design, the precise machining results and the blank assembly tests of the cavity...
We present the latest developments in the optics design of the FCC-hh particle collider. The main change with respect to previous designs is the change of the arc cells from 12 to a 16-dipole FODO scheme which makes full use of the available aperture and increases the dipole filling factor. The updated design of insertions is also discussed, adapting the changes in the layout requirements from...
With the increasing complexity of colliders, it is crucial to consider many physical phenomena in accelerator simulation studies, including complex effects such as radiation, beam-beam, and impedance. However, existing simulation tools are often outdated or focus on a single aspect. To address this challenge, the CHART collaboration is developing a software framework that integrates different...
The design of the electron-positron Future Circular Col-
lider (FCC-ee) challenges the requirements on optics codes
(like MAD-X) in terms of accuracy, consistency, and per-
formance. This paper analyses MAD-X TWISS, TRACK
and EMIT modules by comparing their mutual consistency,
absolute accuracy and stability and will make improvement
proposals.
To efficiently and reliably enable the operation of future large-scale research facilities, it is indispensable to conduct multi-area and multi-disciplinary research, taking into account in the facility design not only scientific aspects, but also energy-related challenges. At the Karlsruhe Institute of Technology (KIT), the innovative research laboratory KITTEN has recently been developed,...
We investigate the effects of the updated beam and machine parameters on the electron cloud instability for the FCC-ee arc dipole & drift regions by considering ‘ECLOUD’ and ‘Furman-Pivi’ secondary emission yield models and realistic photoemission yield values.
The FCC-ee will be installed in a 91 km long tunnel at around 200 m underground. The size of the project, the tunnel configuration and stability, the number of components to align and the alignment tolerances raise unprecedented challenges. From the manufacturing of the components to the relative alignment of these components during technical shutdowns, all the alignment steps are impacted. ...
In order to explore potential improvements to the current lattice design for FCC-ee, this work looks at the use of Combined Function Magnets (CFM) within the short straight sections of the arc cells. The use of CFMs introduces a change in the damping partition numbers. To avoid this it is necessary to maintain the values of the Synchrotron Radiation Integrals (I2 and I4), which are used to...
An alternative lattice and beam optics have been developed for the FCC-ee which aim to provide large dynamic aperture and momentum acceptance via the correction of high order nonlinearities. In this presentation, the synchrotron radiation sources have been evaluated and a synchrotron radiation collimation scheme has been developed to protect the central beam pipe within the particle detector...
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....
We present recent developments and PSD data from the FCC-BESTEX experimental beamline at the KARA synchrotron at KIT on one FCC-hh beam screen, as well as future plans for measuring FCC-ee vacuum paper prototypes at the beamline. In addition, we demonstrate VacuumCOST, a new software tool that has been developed to enable more dynamic MolFlow simulations, including the pressure evolution in...
Diboson production processes constitute an interesting probe of New Physics related to the Higgs boson and the EW sector. We study the 𝑊ℎ and 𝑍ℎ production processes, with leptonically decaying gauge bosons and both $h\to b\bar b$ and $h\to\gamma\gamma$ decay channels. We study these processes in the SMEFT framework and derive bounds on six dimension-6 operators. The possibility of using the...
Euclid Techlabs LLC, in collaboration with JLab and Fermilab, has developed a new ceramic material with a finite DC electrical conductivity combined with a low RF loss tangent for use in high power coupler windows. The goal of the project was to develop windows with a loss tangent not exceeding that of alumina but with significantly increased DC conductivity for effective electrical discharge....
The study of Dynamic Aperture (DA) plays a crucial role in understanding non-linear beam dynamics in circular accelerators. The DA defines the phase-space region where particles' motion remains bounded over a finite number of turns. It is affected by various elements such as the regular magnetic lattice, magnetic field imperfections, beam-beam effects, electron clouds, and other nonlinear...
My poster has three topics: the dump designs for the CPEC collider and linac, the synchrotron radiation shielding for magnet insulations, and the estimation for radioactivity production in the surrounding materials.
A design for the collider dump including a dilution system is updated. The material of the dump core is made of graphite while this core is surrounded with iron. The maximum...
The report presents estimates of the physical parameters of the depolarizer for FCC-ee in three main modes of its use.
In the first mode, it is supposed to produce resonant depolarization of one of the polarized pilot bunches by sweeping the frequency of the depolarizer. The pulse of the depolarizer in this mode has a duration of only about 20 ns, and the duty cycle of its inclusion is...
