Conveners
FCC accelerator technical design: Magnets and power conversion
- Sakhorn Rimjaem
FCC accelerator technical design: Vacuum
- Flyura Djurabekova (University of Helsinki)
FCC accelerator technical design: Injection & Instrumentation
- Simone Liuzzo (ESRF)
FCC accelerator technical design: Synergies and innovation (i)
- David Martin
FCC accelerator technical design: Synergies and innovation (ii)
- Giovanni Lamanna (Centre National de la Recherche Scientifique (FR))
FCC accelerator technical design: Beam Interception Devices
- Simone Gilardoni (CERN)
FCC accelerator technical design: Machine protection and availability
- Carsten Peter Welsch (Cockcroft Institute / University of Liverpool)
We will summarize the arc magnet designs proposed for the GHC optics baseline in the Feasibility Study Report, and compare it with alternative designs for the LCC optics. We will conclude with an overview of the collider magnet work plan for the Pre-TDR phase.
This presentation reviews recent progress in the design of the high energy booster magnets. We will summarize the proposed designs of the main arc magnets โ dipoles, quadrupoles, and sextupoles โ from the feasibility study report. Results from magnetic measurements of a short prototype dipole will be presented, highlighting implications for low-field performance. Finally, we will outline...
Permanent magnets and conventional electromagnets were studies as candidates for the FCC-ee transfer lines. The preliminary 2D design was performed to evaluate the engineering parameters and cost for both options. The results were discussed and the electromagnets have been approved as a base line due to their capability of the magnetic field adjustment in a wide range, that is an important...
This talk presents updated results on optimal powering solutions for the FCC-ee, based on the latest data from the Feasibility Study.
It includes new magnet parameters, CO2-equivalent material mass estimation for environmental assessment and updated power losses with the top-up scheme of the booster.
A global optimisation tool, developed in collaboration with CERN expert groups, is...
The vacuum system requirements for the FCC-ee arcs will be presented, highlighting key challenges and expected performance. An update of the design of the vacuum chambers and overall vacuum layout for both the collider and the booster will be described. Innovative approaches under consideration include additive manufacturing techniques (such as 3D printing and thermal spray), friction stir...
In the current FCC-ee design, the synchrotron radiation (SR) power in the collider ring reaches 100MW for all operation modes. This magnitude presents thermal, mechanical, vacuum and beam lifetime issues that need to be carefully predicted and managed.
Using the ray-tracing codes MolFlow and SynRad, an estimation of the the pressure profiles, static and dynamic, is presented for the booster...
The Future Circular Collider โ electron-positron (FCC-ee) demands an ultra-high vacuum environment to reach its ambitious performance targets. At the heart of this vacuum system lies a deceptively simple yet critically important component: the bake-out system. Its role? To activate and regenerate the Non-Evaporable Getter (NEG) coating inside the vacuum chamber through a high temperature...
In the FCC-ee study, it is proposed that electron and positron beams circulate at high current and high energy in a 91-km circumference twin ring. The present operational scenario foresees a first running step at an energy of 45.6 GeV and around 1.4 A current, which would generate copious amounts of synchrotron radiation power and flux. To guarantee a quick decrease of the photon desorption...
The use of a common RF section in the Higgs and ttbar modes of the FCC-ee collider requires the separation of the beam outgoing from RF at point H. An electromagnetic separator (EMS) taking advantage of a combination of DC electric and magnetic fields has been first considered. The main challenges such has minimising the impact on the incident beam, high-voltage breakdown and device topology...
This presentation summarises the feasibility studies conducted for the various kicker systems needed to transfer the beam between the different FCC-ee machines. The selected kicker design is presented, reflecting the most recent updates in system requirements. The feasibility and technology options for both the beamline elements and pulse generators are discussed, with emphasis on the key...
Longitudinal profile monitoring is crucial for assessing beamstrahlung effects in the FCC-ee, as well as for energy calibrationโboth fundamental from the physics point of view. From an operational perspective, bunch-by-bunch longitudinal profiles will be needed during machine commissioning and to assess the quality of bunches freshly injected from the booster. To overcome the limitations...
Structured Laser Beams (SLBs) are pseudo-non-diffractive optical beams characterized by a low-divergence Inner Core (IC), down to 10 ฮผrad. The dimensions of the IC vary depending on the SLB generator setup. Due to their small IC diameter and theoretically infinite propagation distance, experimentally confirmed over 900 m, SLBs offer strong potential as reference lines in long-distance...
Beam signal digitisation during FCC operation presents significant challenges for existing acquisition technologies, including the demand for high analog bandwidth, the capability to manage high repetition rates, and robustness in radiation-intense environments. In this work, we propose an electro-optical readout system based on photonic time-stretch techniques to address these limitations. In...
In this contribution we report on recent advancements of the HNFS project for the transverse beam diagnostics of FCC-ee. The project aims at developing novel nanostructured targets to monitor the full 2D beam profile with the Heterodyne Speckle technique. We will present preliminary numerical and experimental results concerning the target design, prototyping and testing, as well as the current...
The combination of high energies, high intensities, and very low emittances of electron and positron beams at the FCC-ee offers an extraordinary possibility of making a unique $\gamma$-source. This involves using a novel technique, which in addition allows one to operate such a source concurrently with the nominal $e^+e^-$ collisions.
Using a low-energy ERL beam with short bunches, the...
Energy consumption represents an increasing critical challenge for particle physics research laboratories like CERN. This issue is particularly significant in large accelerator facilities, where normal conducting magnet technology plays a fundamental role in beamline design. In this context, R&D on high-temperature superconducting (HTS) magnets offer promising solutions to improve energy...
To achieve physics performance at the Future Circular electron-positron Collider (FCC-ee), luminosity and beam lifetime must be maintained at close to design specifications.
Alongside global feedbacks, a fast feedback system is proposed to mitigate beam offset errors at the interaction points (IP), caused by magnet vibrations or other time-varying errors.
To identify the performance...
At the FCC-ee, Beamstrahlung radiation generated at the interaction points produces intense photon beams, with power reaching up to 370 kW per interaction point at Z-pole operation. To absorb this energy, a dedicated beam dump based on liquid lead (Pb) is under development. Liquid lead is selected due to its high density, high atomic number, and favorable thermal properties, making it a...
FCC-ee requires a collimation system to isolate unavoidable beam losses and reduce particle backgrounds in the detectors, and to protect the machine in case of excessive beam losses from unstable or mis-steered beams at stored energies of 17.5MJ. The system is composed of primary and secondary collimators for betatron and momentum collimation, which will be located in one of the technical...
The radiation fields generated by synchrotron photons and beam losses pose a significant challenge for FCC-ee equipment. The annual ionizing dose can reach MGy-levels in the collider tunnel and requires dedicated shielding configurations in order to reduce the need of expensive radiation-hard equipment. A first shielding concept for the collider arc dipoles has been conceived in the...
Managing radiation from primary synchrotron photons is a major design challenge for the FCC-ee, as prolonged exposure can degrade tunnel infrastructure and critical machine components. Effective shielding is therefore essential, not only to protect equipment and maintain operational reliability, but also to minimize the need for costly radiation-hardened materials.
The current shielding...
To reach integrated luminosity goals, the FCC-ee aims to be operational for minimum 80 % over the scheduled 185 physics days each year. For comparison, the Large Hadron Collider (LHC) averaged 72 % in 2015-2024. Characteristics of the FCC-ee relating to size, complexity and ambitious technical objectives make availability one of the main challenges to its physics deliverables. This...
Due to the high brightness of the FCCee beams, the damage potential of these beams is comparable to those of the LHC. Fast failure modes of the FCCee have been identified, requiring a fast reacting and ultra reliable machine protection system.
This presentation gives an overview of the present state of identified failure modes of the FCCee and resulting requirements for a coherent machine...
The stored beam energy of FCC-ee will reach 17.5 MJ per beam during the Z-mode operation at 45.6 GeV. Due to the very small beam emittances, the resulting extremely high energy densities pose a significant risk of damage to collider components in case of failures leading to beam impact. This study investigates the criticality of powering failures in the main dipole circuits. The time-dependent...
Stored energies in the FCC-ee colliding ring are expected to be just below 20 MJ for the Z-pole configuration - still one order of magnitude below that of the LHC. However, due to the extremely small vertical beam size, the beam energy density remains high enough to pose a risk of damaging the accelerator. A beam loss system must therefore be capable of detecting losses quickly enough to...
