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FCC Week 2026

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→ Europe/Helsinki
Main building (University of Helsinki)

Main building

University of Helsinki

Fabianinkatu 33, 00170 Helsinki
Frank Zimmermann (CERN), Michael Benedikt (CERN)
Description

We are delighted to announce the twelfth edition of the Future Circular Collider (FCC) Conference. FCC Week 2026 will take place in Helsinki, Finland, from 8 to 12 June 2026, at the University of Helsinki.

This will be the first collaboration meeting following the publication of the FCC Feasibility Study report. Aligned with the final phase of the 2025/26 European Strategy update process, it will provide a comprehensive review of the FCC study's progress to date and mark the start of the next project phase.

The conference will gather international experts from various fields of science and technology to advance ongoing design work and strengthen the international collaboration for CERN’s proposed post-LHC research infrastructure. The 2026 event is organised in collaboration with the University of Helsinki and the Helsinki Institute of Physics (HIP), as well as with the University of Copenhagen (Denmark), University of Tartu (Estonia), LUT University (Finland), Universität Rostock (Germany), Riga Technical University (Latvia), Vilnius University (Lithuania), University of Oslo (Norway), University of Silesia in Katowice (Poland) and Uppsala University (Sweden).

 

Programme Structure

Plenary Sessions

The conference will open with a day of plenary keynote presentations featuring distinguished international speakers from science, industry, and policymaking.

The Monday (08/06) sessions will provide:

·         The sharpened physics cases of the FCC integrated programme

·         Key results since the publication of the FCC Feasibility Study report

·         Updates on the local implementation and stakeholder engagement

·         Progress on subsurface investigations

·         Summary of the environmental initial state analysis

·         A comprehensive overview of ongoing activities across all study areas

·         Planning for the next phase of the FCC project in light of the EPPSU.

A special plenary session on Wednesday (10/06) will focus on Finland’s activities in particle physics and related domains.

A closing plenary session on Friday (12/06) will showcase the key conclusions from the parallel sessions.

 

Parallel Sessions

Specialised parallel sessions on Tuesday, Wednesday and Thursday will cover:

  • Physics and Experiments
  • Accelerator design
  • Technology R&D
  • Civil Engineering
  • Scheduling, Planning and Resources

 

These topical sessions create opportunities to forge new collaborations, share research findings, and build lasting relationships within the global particle physics community and beyond.

 

Industry & Technology Day

During FCC Week 2026, a dedicated workshop and industry day will focus on the impact of Big Science projects on society and the economy, with particular attention to the role of CERN and the FCC collaboration in engaging with industry through the International Liaison Officer (ILO) network. The industry day will provide a forum to strengthen ILO-supported interactions and to identify potential areas for collaboration between the FCC project and industrial partners. More information here

 

Awards

Continuing the established tradition of recognising excellence within the FCC community, FCC Week 2026 will feature the FCC Innovation Awards, highlighting outstanding contributions to innovation, technology development and impact. 

In line with its focus on the full lifecycle of large-scale research and technology infrastructures, FCC Week 2026 will also provide an opportunity to publish technical, organisational and socio-economic outcomes in the EPJ journal series. In this context, FCC related science policy, programme, sustainability, planning and organisation topics will be considered for publication in EPJ Research Infrastructures, a recently launched fully Open Access journal from Springer Nature dedicated to research and technology infrastructures. Contribution titles and drafts should be submitted with the FCC Week Indico site. A dedicated call for papers will be issued soon.

FCC Early Career Researcher (ECR) Award 2026 jointly organised by CERN and Springer-Nature will support young scientists and professionals who contribute innovative, relevant and technically robust work that supports the long-term vision of the FCC project. Three prices will be awarded and each winner receives:

·         Monetary award of 1000 euro

·         Support for publication of the submitted article as Open Access publication with Springer Nature

·         Certificate of achievement

Collaborative submissions are welcome and encouraged. Draft papers submitted via the FCC Indico site until 30 April 2026 (18h00 CET) will be considered eligible for participation in the award.

 

Poster Session

Researchers are invited to showcase their work during the dedicated poster session on Tuesday (09/06). This session provides a platform to present results and developments contributing to the FCC programme, including:

·         Advances in particle physics relevant to the FCC physics case

·         Progress in accelerator physics, technology and infrastructure studies supporting the FCC design

·         Opportunities for exchange and networking within the FCC collaboration and with the wider research community

 

Calls for papers and awards
Code of Conduct
Poster
Programme overview
Contact
Registration
FCC Week 2026 Registration
627 / 650
Apply for participation
Participants
626 View full list
  • Mon, June 8
    • 8:30 AM → 10:05 AM
      Monday plenaries: Opening F2044 Auditorium

      F2044 Auditorium
      Convener: Philippe Chomaz
      • 8:30 AM
        Welcome from the Rector of the University of Helsinki 10m
        Speaker: Sari Lindblom (University of Helsinki)
      • 8:40 AM
        Welcome from the Director of the Helsinki Institute of Physics 10m
        Speaker: Katri Huitu (University of Helsinki)
      • 8:50 AM
        Practical information 10m
        Speaker: Dr Flyura Djurabekova (Helsinki Institute of Physics (FI))
        FCC_welcome_FD.pdf
        FCC_welcome_FD.pptx
      • 9:00 AM
        Opening address from the Research Council of Finland and the Ministry of Science and Culture 10m
        Speaker: Paula Eerola (Research Council of Finland)
      • 9:10 AM
        Opening remarks from CERN Director General 20m
        Speaker: Mark Thomson (CERN)
        FCC-Week-Opening-Plenary-Thomson.pdf
        FCC-Week-Opening-Plenary-Thomson.pptx
      • 9:30 AM
        The FCC: a view from CERN Council 20m
        Speaker: Costas Fountas (University of Ioannina (GR))
        FCC Week Helsinki PoC talk V3.pdf
      • 9:50 AM
        Opening address from EU Commissioner for Economy and Productivity, Implementation and Simplification 15m
        Speaker: Valdis Dombrovskis (European Commission)
    • 10:05 AM → 10:35 AM
      Coffee Break 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 10:35 AM → 12:30 PM
      Monday plenaries: Morning session (ii) F2044 Auditorium

      F2044 Auditorium
      Convener: Katri Huitu (University of Helsinki)
    • 12:30 PM → 2:00 PM
      Lunch break 1h 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 2:00 PM → 3:40 PM
      Monday plenaries: Overview by FCC Coordinators F2044 Auditorium

      F2044 Auditorium
      Convener: Malika Meddahi (CERN)
    • 3:40 PM → 4:00 PM
      Coffee break 20m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 4:00 PM → 5:40 PM
      Monday plenaries: PED plenary session F2044 Auditorium

      F2044 Auditorium
      Convener: Chris Quigg (Fermi National Accelerator Lab. (US))
    • 6:00 PM → 8:00 PM
      Welcome Reception 2h HELSINKI CITY HALL

      HELSINKI CITY HALL

      Pohjoisesplanadi 11-13, Helsinki
  • Tue, June 9
    • 8:30 AM → 10:00 AM
      Accelerator Technical Design: Magnet support & alignement F3017

      F3017
      • 8:30 AM
        Overview of FCC-ee Alignment Strategy: Surveying Concept and Research Directions 25m
        Speaker: Dirk Mergelkuhl (CERN)
        Overview_Alignment_strategy_Mergelkuhl.pdf
        Overview_Alignment_strategy_Mergelkuhl.pptx
      • 8:55 AM
        Uncertainty Propagation in FCC-ee arc Alignment: Results of First Simulation Studies 25m

        The installation of the components in the FCC-ee arcs require a geometrical network throughout the entire tunnel to enable the initial positioning and the precise alignment of the components. This First Geodetic Network must be determined with an uncertainty of a few millimeters.

        This work presents the first simulation studies of the First Geodetic Network implemented over the full FCC underground infrastructure. It describes how the network has been designed to reproduce a realistic geometry and then focuses on uncertainty propagation using different alignment strategies and measurement configurations in order to evaluate their impact on the overall network accuracy. Attention is given to the identification of relevant measurement instruments and configurations for the alignment of the FCC-ee.

        These first results provide an initial assessment of the expected uncertainty behaviour within the First Geodetic Network and contribute to the development of optimized measurement strategies for the FCC-ee.

        Speaker: Vincent Gerligand (CERN / Conservatoire National des Arts et Metiers Cnam (FR))
        FCC_Week_Vincent_Gerligand.pdf
        FCC_Week_Vincent_Gerligand.pptx
      • 9:20 AM
        Status of the Fiducialisation Strategy, Alignment Test Setup and Supports 20m
        Speaker: Bingru Yang (CERN)
        FCC_2026_Presentation_Fiducialisation_BYang.pdf
        FCC_2026_Presentation_Fiducialisation_BYang.pptx
      • 9:40 AM
        Development of a Structured Light-Based System for Accelerator Alignment: A Progress Report 20m

        Next-generation colliders, such as the Future Circular Collider (FCC), require precision in the order of micrometers over distances of hundreds of meters. While traditional straight-line alignment technologies like Wire Position and Hydrostatic Leveling Systems are highly accurate, they have several drawbacks, such as deployment complexity. Optical alignment techniques offer a promising alternative, however, they suffer heavily from atmospheric turbulence and refraction when operated in ambient air.

        To overcome these atmospheric limitations, a system utilizing a pseudo-nondiffracting Structured Laser Beam (SLB) was previously developed and successfully tested within a protective vacuum tube. While this vacuum-enclosed SLB system proved highly accurate, implementing long-distance vacuum infrastructure in an accelerator tunnel adds significant complexity and operational constraints.

        Recent R&D efforts focus on mitigating the drawbacks of the previously developed SLB system. This report highlights our latest advancements: maximizing the signal-to-noise ratio by concentrating laser intensity into the beam's central core, implementing a dual-wavelength approach to eliminate the need for a vacuum pipe by dynamically compensating for angular refraction caused by refractive index non-homogeneities, and evaluating alternative beam geometries such as Layer Beams. Furthermore, we highlight a recent integration milestone, the successful deployment of the SLB as an alignment laser under real experimental conditions at the CLEAR accelerator facility.

        Speaker: Martin Dusek
        20260609_SL_FCC.pdf
        20260609_SL_FCC.pptx
    • 8:30 AM → 10:00 AM
      FCC-ee Accelerator: Optics Design and Parameters F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Dr Tatiana Pieloni (EPFL)
      • 8:30 AM
        LCC optics design challenges and next steps 20m
        Speaker: Dr Pantaleo Raimondi (Fermi National Accelerator Lab. (US))
        LCC Helsinki Raimondi.pdf
        LCC Helsinki Raimondi.pptx
      • 8:50 AM
        Parameter optimization (BB, impedance and RF) and how reliable are simulations 20m
        Speaker: Xavier Buffat (CERN)
        2026-06-09_parameter_opt.pdf
      • 9:10 AM
        The LCC Optics and its Optimization Across All Energies 20m
        Speaker: Marc Andre Jebramcik (CERN)
        2026_06_09_FCC_Week_LE.pdf
        2026_06_09_FCC_Week_LE.pptx
      • 9:30 AM
        LCC DA/MA, beam parameters, emittances and lifetimes at different energies 15m
        Speaker: Dr Katsunobu Oide (KEK High Energy Accelerator Research Organization (JP))
        LCC_BB_Oide_260609.pdf
        • Beam-beam lifetimes have been estimated by SAD+BBWS for  Z,  W,  Zh, and tt with the latest LCC lattices.
        • The lifetime with weak-strong beam-beam and beamstrahlung look acceptable.
        • The lifetime has been improved by (1) reducing bunch charge together with (2) reducing the vertial emittance at collision.
          • The energy spread due to beamstrahlung seems critical, NOT the beam-beam parameter.
          • The resulting emittance ratio   becomes smaller than 1/1000, which can be critical depending on the machine tuning methods.
          • If such a small emittance ratio is not possible, one may have to reduce the luminosity and/or lifetime… 
      • 9:45 AM
        LCC optics tuning and modelling tools 15m
        Speaker: Kevin Andre
        TuningFCCWeek.pdf
        TuningFCCWeek.pptx
    • 8:30 AM → 10:00 AM
      Physics, Experiments and Detectors: Physics Studies (i) F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Conveners: Bogdan Malaescu (LPNHE-Paris CNRS/IN2P3 (FR)), Juan Alcaraz Maestre (CIEMAT - Madrid (ES))
      • 8:30 AM
        Electroweak physics at FCC-ee: Status and Plans 20m
        Speaker: Matteo Defranchis (CERN)
        EW_FCC_Helsinki.pdf
      • 8:50 AM
        QCD & gammagamma at FCC-ee: Status and Plans 15m
        Speaker: Giovanni Stagnitto (INFN e Universita Genova (IT))
        QCD_FCCweek26.pdf
      • 9:05 AM
        Flavor Physics at FCC-ee: Status and Plans 20m
        Speaker: Guy Wilkinson (University of Oxford (GB))
        FCC_wk_flav.pdf
      • 9:25 AM
        BSM Physics at FCC-ee: Status and Plans 15m
        Speaker: Rebeca Gonzalez Suarez (Uppsala University (SE))
        FCC_week_2026_BSM.pdf
      • 9:40 AM
        Precision Calculation for FCC-ee: Status Plans 20m
        Speaker: Janusz Gluza (University of Silesia (PL))
        FCC_Week_Helsinki_2026.pdf
    • 8:30 AM → 10:00 AM
      Superconducting Radio Frequency: FCC Baseline F3020

      F3020
      • 8:30 AM
        SRF Roadmap 18m
        Speaker: Frank Gerigk (CERN)
        SRF-roadmap.pdf
        SRF-roadmap.pptx
      • 8:48 AM
        Triston demonstrator program 18m
        Speaker: Nuria Catalan Lasheras (CERN)
        FCCweek26_ncl_v3.pdf
        FCCweek26_ncl_v3.pptx
      • 9:06 AM
        CEA contribution to SRF for FCC 18m

        The Future Circular Collider (FCC) project requires reliable major advances in superconducting radiofrequency (SRF) technologies to achieve its ambitious performance, efficiency, and sustainability objectives. Leveraging decades of experience in accelerator science and SRF systems, CEA contributes to several key technological areas, including SRF cavities, cryomodules, fundamental power couplers (FPCs), and advanced manufacturing processes.
        CEA's activities on SRF cavities focus on advanced materials, surface treatments, thin-film superconducting coatings, and cryogenic RF characterization. These efforts aim to improve accelerating gradients, reduce RF losses, and increase quality factors, thereby enhancing accelerator efficiency while lowering operational costs. Particular emphasis is placed on understanding the impact of materials and surface preparation on cavity performance.
        CEA also brings extensive expertise in the cryogenic and RF tests, assembly, integration and in-situ metrology of SRF cryomodules within dedicated clean-room environments. This know-how is essential for ensuring the cleanliness standards required to preserve cavity performance and reliability in large-scale accelerator facilities. In parallel, CEA is developing innovative assembly approaches based on cobotization and automation technologies to improve reproducibility, quality control, worker safety, and industrial scalability for future FCC production needs.
        In the area of fundamental power couplers, CEA contributes to the design, qualification, and testing of high-power components for reliable continuous-wave operation. Activities include RF, thermal, and mechanical optimization, ceramic window technologies, and high-power conditioning under realistic cryogenic conditions.
        Through close collaboration with CERN and international partners, CEA provides multidisciplinary expertise spanning materials science, RF engineering, cryogenics, clean-room assembly, and advanced manufacturing, supporting the FCC program and future generations of SRF-based accelerator infrastructures.

        Speaker: Dr Thomas Proslier
        FCC-week-2026-TP.pdf
        FCC-week-2026-TP.pptx
      • 9:24 AM
        European collaborations supporting the 800 MHz SRF program for FCC-ee 18m

        A coordinated European effort is being established to develop and validate 800 MHz SRF technology for FCC-ee. CERN, IJCLab, CEA, ESS, DESY and HZB are collaborating to deliver a high-gradient, high-Q0 cryomodule demonstrator by 2031 as a first step towards industrialization. The new E2-SCALE European project will support significantly this initiative which is based on previous European collaborations and which will benefit from close interactions with Fermilab and other US laboratories.

        Speaker: Franck Peauger (CERN)
        2026_06_09-800 MHz european program-Peauger.pdf
        2026_06_09-800 MHz european program-Peauger.pptx
      • 9:42 AM
        High-Efficiency RF Power Sources for Future Large-Scale Facilities 18m

        The CEPC collider requires approximately 60 MW of beam power, making the efficiency of RF power sources a key determinant of overall project cost-effectiveness. High-power, high-efficiency klystrons are therefore particularly attractive due to their superior performance compared with alternative RF amplifiers.
        At IHEP, a 650 MHz continuous-wave (CW) high-efficiency klystron prototype, completed in 2024, has demonstrated an output power of 803 kW with a peak efficiency of 78.5%. In parallel, a multi-beam klystron (MBK) designed to achieve efficiencies exceeding 80% is currently under development and is scheduled for high-power testing in 2026.
        Furthermore, an energy-recovery klystron (ERK) targeting an efficiency above 85% is under fabrication and is expected to undergo high-power testing by the end of 2026.
        For the CEPC linear accelerator (Linac), high-power S-band and C-band klystrons with output power levels of 80 MW are also being developed at IHEP. The S-band design targets an efficiency exceeding 55%, and two prototype variants are planned for experimental testing in early 2026.
        In addition, a very high-efficiency and high power tristron concept was proposed in 2024. IHEP has initiated the development of grid assemblies and other key enabling technologies to support future prototype fabrication.

        Speaker: Prof. Zusheng Zhou
        High-Efficiency RF Power Sources for Future Large-Scale Facilities.pdf
    • 8:30 AM → 10:00 AM
      Technical Infrastructure: Electricity & Energy Management F3005

      F3005
      • 8:30 AM
        FCC electrical grid and infrastructure - status and update 22m

        This presentation provides an updated overview of the FCC electrical grid and infrastructure following the Feasibility Study Report. The grid concept has been further developed to improve reliability according to updated requirements. The infrastructure of the various underground areas has been refined or preliminarily defined to support the integration studies of these facilities. In addition, the presentation outlines the expected updates to the electrical grid resulting from changes in the machine optics, together with the next steps and the key inputs required for future developments.

        Speaker: Charline Marcel (CERN)
        FCC electrical grid and infrastructure - status and update.pdf
        FCC electrical grid and infrastructure - status and update.pptx
      • 8:52 AM
        Return of experience of RF 2.0 project: network studies on LHC and future deployments for FCC 22m

        This presentation provides an overview of the preliminary results of the RF2.0 project related to the ongoing electrical grid analysis activities on LHC. Particular attention is given to the investigation of electrical perturbations and network events that can lead to accelerator downtime and impact overall machine availability. The analysis aims to improve the understanding of the interaction between the electrical network and the accelerator infrastructure, identifying the most critical systems affecting operational continuity.
        In addition, the presentation introduces the studies currently being carried out on LHC to integrate, through software-based simulations, potential solutions aimed at mitigating the impact of grid disturbances and improving accelerator’s availability.
        Finally, these activities are expected to provide valuable guidance for the future FCC electrical infrastructure, contributing to the definition of more reliable architectures and enhanced power grid stability.

        Speakers: Mario Parodi (CERN), Marta Gomis
        Return+of+experience+of+RF2.0+project.pdf
        Return+of+experience+of+RF2.0+project.pptx
      • 9:14 AM
        Improving FCC Electrical Network Availability: Mitigating Voltage Dips with Unified Power Flow Controllers 22m

        Power quality events can have a direct impact on the availability of the Future Circular Collider by causing undesired trips of sensitive equipment. At the same time, maintaining a high level of power quality is essential to ensure stable and reliable operation of the machine and its technical infrastructure.
        This presentation discusses how machine availability could be improved through the use of Unified Power Flow Controllers. Beyond their conventional role in reactive power control and harmonic mitigation, UPFCs can also be used to compensate voltage perturbations, dips, and other power quality events that are already known to affect the operation of present accelerator facilities such as the LHC.
        The presentation compares possible strategies to increase the robustness of FCC equipment against network perturbations, with a particular focus on a centralized compensation approach based on UPFC technology. It also introduces the ongoing R&D activities aimed at developing and validating this topology, including the proposed converter architecture, the expected performance benefits, and the path towards a representative demonstrator for accelerator applications.

        Speaker: Dr Davide Aguglia (CERN)
        FCC Week 2026 UPFC_Davide.pdf
        FCC Week 2026 UPFC_Davide.pptx
      • 9:36 AM
        Integrating Renewables Using Energy Storage Systems: A Tool to Explore Different Scenarios 22m
        Speaker: Corentin Pierre Boennec (Laplace)
        FCC_week_09_06.pdf
        FCC_week_09_06.pptx
    • 8:30 AM → 10:00 AM
      iRIS: Project organization U3039

      U3039
    • 10:00 AM → 10:30 AM
      Coffee break 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 10:30 AM → 12:00 PM
      Accelerator Technical Design: Vacuum F3017

      F3017
      Convener: Cedric Garion (CERN)
      • 10:30 AM
        Synchrotron Radiation in the MDI region 20m

        The FCC-ee machine-detector interface (MDI) region, where the two beams meet, receives synchrotron radiation (SR) from upstream dipoles and quadrupoles. When these SR photons hit the vacuum chamber wall, they can create photoelectrons and desorb molecules from the surface, increasing the background gas pressure and contribute to electron cloud formation during operation.

        To estimate the magnitude of these effects, we use the Monte Carlo codes SynRad (for SR) and MolFlow (for vacuum), that are developed at CERN's TE-VSC group. The codes perform ray tracing (of photons or molecules), and can work on CAD models of arbitrary complexity, making them suitable for a detailed aanlysis of the region, including collimators and absorbers.

        SynRad studies provide the absorbed photon flux on the wall, which is used as input to MolFlow for vacuum simulations to determine the pressure. In light of the results, an initial proposal is presented to protect the wall from direct incidence.

        Speaker: Marton Ady (CERN)
        2026-06 fcc week mdi sr.pdf
        2026-06 fcc week mdi sr.pptx
      • 10:50 AM
        Impedance considerations for the FCC-ee vacuum system 20m

        The vacuum system of the FCC-ee must satisfy stringent beam-impedance requirements arising from high beam currents, short bunch lengths, and tight constraints imposed by collective effects. In particular, controlling beam-coupling impedance is essential to limit parasitic beam-induced power losses, mitigate higher-order mode excitation, and protect vacuum components from excessive thermal loads. This work examines how impedance considerations from an early design stage influence the development of individual vacuum-system components. Emphasis is placed on electromagnetic behaviour, material selection, thin-film coating choices, surface quality, the identification of discontinuities, and component placement with respect to their impact on the longitudinal and transverse beam impedance. Electromagnetic simulations and impedance estimates are employed to optimise component geometries, ensure RF continuity, and assess the contribution of individual elements to the machine's overall broadband and narrowband impedance budget. Design strategies aimed at minimising impedance while maintaining vacuum performance, mechanical tolerances, thermal management, and integration constraints are also discussed. The study highlights the necessity of a global impedance-aware design approach for the FCC-ee vacuum system and identifies critical trade-offs between accelerator performance and engineering constraints.

        Speaker: Patrick Krkotic
        FCCWeek26_Vacuum_Impedance_Krkotic.pdf
      • 11:10 AM
        Thermo-mechanical behaviour of the FCC-ee arc cell vacuum layout 20m

        The mechanical design of the FCC-ee vacuum system must withstand thermal and mechanical loads during bake-out and operation while accounting for the integration with interfacing components.
        To this end, an extensive thermo-mechanical analysis was carried out on the collider arc half-cell by means of an experimentally validated FE model. Heat dissipation and thermal deformations of the vacuum system were evaluated and are presented in this work, with particular focus on the bake-out and Z-mode operation phases. The Z-mode operation was selected as the most critical scenario, since the synchrotron radiation flux produces the highest power density on the synchrotron radiation absorbers.
        Results from experimental bake-out tests performed on a vacuum chamber–yoke system prototype are also presented. In addition, a new bake-out technology based on heating cables bonded directly onto the vacuum chamber is introduced. Different techniques for cable integration are currently under investigation.
        Finally, a comparison between simulations and measurements is presented. This study will enable the optimization of the thermo-mechanical behavior of the FCC-ee vacuum system.

        Speaker: Valentina Giovinco (CERN)
        FCC week 2026_Valentina Giovinco.pdf
        FCC week 2026_Valentina Giovinco.pptx
      • 11:30 AM
        Advances on the design and experimental validation of the Synchrotron Radiation Absorber 20m

        In the FCC-ee study, electron and positron beams are foreseen to circulate at high current and energy in a 91 km circumference twin-ring collider. The current operational scenario includes an initial running stage at a beam energy of 45.6 GeV and a current of approximately 1.4 A, generating large amounts of synchrotron radiation power and flux. To guarantee rapid reduction of the photon desorption yields and so a fast vacuum conditioning, it has been proposed to use localized Synchrotron Radiation Absorbers (SRA) along the vacuum chamber, spaced about 5-6 m apart. These absorbers would also help contain the high-energy Compton-scattered secondaries once the beam energy is increased up to 182.5 GeV. Each absorber features a tapered interception surface, on which a total power between 3.3 and 4.5 kW is deposited and dissipated through a dedicated water-cooling circuit integrated within the component.

        The current absorber design is intended to be 3D printed. This approach enables the manufacturing of the complex SRA geometry together with conformal cooling channels, which include heat-transfer enhancement features. To accurately evaluate the thermal-hydraulic performance of the cooling system, Computational Fluid Dynamics simulations are performed. These simulations support detailed thermo-mechanical analyses as well as optimization of alternative cooling circuit designs.

        A thermo-hydraulic test setup equipped with pressure and temperature instrumentation was built to enable the characterization of pressure losses and thermal performance of the different cooling circuit configurations. Simulations and experimental measurements are compared and discussed.

        Speaker: Stefania Grozavu
        FCCWeek2026_StefaniaGrozavu_SRA.pdf
        FCCWeek2026_StefaniaGrozavu_SRA.pptx
    • 10:30 AM → 12:00 PM
      Governance: ICB: International Collaboration Board (closed session) F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Philippe Chomaz
      Agenda
    • 10:30 AM → 12:00 PM
      Physics, Experiments and Detectors: Detectors (i) F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Convener: Lucia Masetti (Johannes Gutenberg Universitaet Mainz (DE))
    • 10:30 AM → 12:00 PM
      Superconducting Radio Frequency: RF Hardware Development and System Integration for FCC F3020

      F3020
      • 10:30 AM
        SRF hardware development program for FCC 18m

        As part of an Accelerator R&D programme at CERN, we aim at building full-scale SRF cryomodule demonstrators at 400 MHz and 800 MHz.
        While the 400 MHz cryomodule (Demo400) will be designed and constructed at CERN, the development of the 800 MHz cavities and cryomodule relies on a collaborative effort with partner institutes. A Horizontal Test Cryostat (HTC) is also under development to pre-qualify dressed cavities powered with their FPCs before being assembled in the cryomodule. In this presentation we illustrate recent progress under this program.

        Speaker: Vittorio Parma (CERN)
        SRF HW development program for FCC.pdf
        SRF HW development program for FCC.pptx
      • 10:48 AM
        SRF system integration & cryomodule design 18m
        Speaker: Karin Canderan (CERN)
        SRF_SYS_CM_Design_KC.pdf
        SRF_SYS_CM_Design_KC.pptx
      • 11:06 AM
        FCC Elliptical Cavity Production 18m

        The FCC-ee collider requires large-scale production of 400 MHz SRF cavities with demanding geometrical and surface-quality specifications. This presentation summarizes ongoing cavity manufacturing developments at CERN, comparing bulk machining and hydroforming as candidate production routes. Recent progress in cavity fabrication is presented, including an assessment of the advantages and limitations of both approaches and the roadmap toward industrialization for FCC cavity series production.

        Speaker: Laura Helene Hannemann (CERN)
        FCC2026_Cavity_Production.pdf
        FCC2026_Cavity_Production.pptx
      • 11:24 AM
        RF kicker design for transverse feedback and depolarizer 18m

        RF kickers are under study to be used for transverse feedback and as a depolarizer for beam energy measurements by resonant depolarization.
        Resonant kickers are proposed as an alternative to the current baseline stripline design. Due to their resonant design, they can achieve a higher shunt impedance than a stripline kicker with the same transverse dimensions while providing sufficient bandwidth for use as coupled-bunch feedback kickers. The resonant behavior can be exploited to achieve the same shunt impedance as a stripline kicker while allowing a larger stay-clear aperture. Higher-order-mode couplers are foreseen to damp beam-induced voltage. The further path for necessary RF design steps of these kickers including power loss and thermal simulations is outlined.

        Speaker: Daniel Sittard (CERN and Karlsruhe Institute of Technology (KIT))
        sittard_RF_kicker_design_for_transverse_feedback_and_depolarizer.pdf
        sittard_RF_kicker_design_for_transverse_feedback_and_depolarizer.pptx
    • 10:30 AM → 12:00 PM
      Technical Infrastructure: Geodesy, Transport & Robotics F3005

      F3005
    • 10:30 AM → 12:00 PM
      iRIS: Work programme presentation and alignment (i) U3039

      U3039
      • 10:30 AM
        WP2 Green beam (part 1): accelerator design 20m
        Speaker: Jacqueline Keintzel (CERN)
        20260609_GhibriKeintzel_GreenBeam_FCCWeek.pdf
        20260609_GhibriKeintzel_GreenBeam_FCCWeek.pptx
      • 10:50 AM
        WP2 Green beam (part 2): accelerator operation optimisation 20m

        The complexity of the accelerator facility demands a high level of automation to maximize the time for physics experiments and reduce energy waste. CERN and GSI collaborate on AI model development using the commonly developed GeOFF software as part of the EURO-LABS project for real-time optimization of beam parameters and experimental setups. In the iRIS project, integration of GeOFF with the EPICS control system enables deployment in local contexts at more than 30 accelerator and telescope facilities. The eco-design driven by the FCC with more than 160 institutes and by ET withmore than 50 institutes worldwide helps to spread the methodology at global scale.
        The capabilities of Geoff for energy-efficiency improvements will be demonstrated within the IRIS project at CERN, GSI/FAIR, and GANIL. Possible applications include hysteresis elimination, beam-loss reduction, and cooling optimization. The capabilities of GeOFF will be further demonstrated by optimizing the operation of the CIME cyclotron at GANIL and extending bayesian optimization to physics driven reinforcement learning.

        Speaker: Sabrina Maria Appel (GSI)
        iRIS-2606020930-wp2_part2-sap_V1.pdf
      • 11:10 AM
        iRIS catching GREMLINs — GReen Energy Monitoring for Large INfrastructure 20m

        Any modern accelerator or large infrastructure complex contains tens of thousands of individually-powered devices — magnet power converters, RF amplifiers, cryogenic plant, water cooling, beam diagnostics, IT infrastructure, or other conventional facility loads — each with its own electrical signature and drift toward end-of-life.
        Instrumenting every device is neither economical nor sustainable, leaving both the operational energy footprint and the early signs of impending equipment failure largely invisible.

        GREMLIN — GReen Energy Monitoring for Large INfrastructure, GSI/FAIR's contribution to the EU-funded iRIS project — addresses both with a single technical approach: Non-Intrusive Load Monitoring (NILM).
        From a small number of upstream measurement points, using software-defined-radio-grade signal processing based on the open-source GNU Radio 4.0 platform, GREMLIN disaggregates the global power consumption into per-device activity and energy accounting, and extracts the spectral, RF and EMI signatures that catch the small "gremlins" — drifts, harmonics, switching anomalies — long before they become hard faults, enabling preventative maintenance scheduling.

        This talk introduces the GREMLIN concept, situates it within iRIS, and outlines its relevance to the operational energy footprint, availability, and life-cycle sustainability of FCC-scale infrastructure.

        Speaker: Dr Ralph Steinhagen (GSI)
        20260608_FCC_Week_iRIS_GREMLIN_rstein_handout.pdf
        GREMLIN Project Page
        Presentation
        Presentation - PDF fallback
      • 11:30 AM
        WP3 Smart cycle 20m
        Speaker: Jef Bergmans
    • 12:00 PM → 1:30 PM
      Lunch break 1h 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 1:30 PM → 3:00 PM
      FCC-ee Accelerator: Optics Corrections and Tuning F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Dr Angeles Faus-Golfe (IJClab IN2P3 CNRS-Université Paris-Saclay (FR))
    • 1:30 PM → 3:00 PM
      Joint effort PED & accelerators: Machine Detector Interface (i) F3020

      F3020
      Convener: Tor Raubenheimer (SLAC)
    • 1:30 PM → 3:00 PM
      Scheduling, Planning and Resources F4050 Pieni Juhlasali

      F4050 Pieni Juhlasali
      Convener: Marzia Bernardini (CERN)
      • 1:30 PM
        Scheduling, Planning and Resources: from Feasibility Study to Technical Design 20m

        The presentation will outline the roadmap for the Project, with a focus on establishing coherent and consistent baselines, ranging from technical aspects to an integrated project framework covering planning, cost, and resource management.
        It will present the objectives of the Reference and Technical Design phases, explaining the methodology to achieve them, as well as highlighting the main challenges and associated risks.
        Furthermore, the presentation will address the overall work organization across the Project, including governance, coordination mechanisms, and the distribution of responsibilities among the different stakeholders.

        Speaker: Marzia Bernardini (CERN)
        FCC-planning scheduling resources rev2_4.pdf
        FCC-planning scheduling resources rev2_4.pptx
      • 1:50 PM
        FCC scheduling: from feasibility to commissioning 20m

        FCC is a long-term project with a complex timeline spanning more than 20 years, from the current feasibility studies through to commissioning. One of the key challenges lies in effectively planning and coordinating activities across this extended period. To address this goal, a Project Master Schedule has been developed in close collaboration with all pillar coordinators.
        The presentation will outline the main drivers of the FCC project and provide an integrated overview across all pillars up to 2033, marking the start of civil engineering. The interdependencies between pillars will be highlighted, illustrating how they shape and define the project’s critical path. The major schedule risks identified will also be presented.
        To ensure a comprehensive overview and to illustrate the target dates for implementation, the installation schedule will also be recalled.

        Speaker: Sarah Agathe Fleury
        FCC_Scheduling_from_feasibility_to_Commissioning_Sarah_Fleury.pdf
        FCC_Scheduling_from_feasibility_to_Commissioning_Sarah_Fleury.pptx
      • 2:10 PM
        Structuring FCC 20m

        Quality and controls across the project. Methods being implemented from PBS to processes.
        This presentation outlines the development of key project management tools designed to support effective coordination, traceability, and quality oversight within the project. It describes the definition of project components through the implementation of a Product Breakdown Structure (PBS), providing a structured framework to enhance consistency and clarity across all activities.
        In addition, the presentation highlights the deployment of a project-wide Engineering Data Management System (EDMS), aimed at improving document control, accessibility, and collaboration among all project teams.
        Together, these tools contribute to the establishment of a robust and integrated project environment, enhancing efficiency, ensuring consistency, and supporting effective long-term project governance.

        Speaker: Beatriz Arias Alonso (CERN)
        FCC_Week_2026-Structuring_FCC.pdf
        FCC_Week_2026-Structuring_FCC.pdf
        FCC_Week_2026-Structuring_FCC.pptx
      • 2:30 PM
        Cost estimate, financial modelling and risks in the FS, and Roadmap for Reference Design 20m

        The FCC Reference Design Phase aims at increasing the maturity, consistency and traceability of the project cost estimates established during the Feasibility Study.
        This contribution presents the methodology implemented for the FS to define the FCC cost baseline and the associated financial risks.
        The presentation will further discuss the evolution from feasibility-level estimates towards more structured cost assessments based on progressively consolidated technical baselines, engineering integration, industrial assumptions and quantity evaluations.
        Attention will be given to the major cost and schedule drivers across civil engineering, infrastructure, accelerator systems and installation activities.
        The financial modelling will also be presented describing the interlinks among/between incomes, costs and project schedules.

        Speaker: Kasia Pokorska (CERN)
        FCC_Week_FAP_KP_Final.pdf
        FCC_Week_FAP_KP_Final.pptx
    • 1:30 PM → 3:00 PM
      Technical Infrastructure: Integration F3005

      F3005
    • 1:30 PM → 3:00 PM
      Territorial Dialogue F3017

      F3017
      • 1:30 PM
        Reflections on territorial dialogue during the Feasibility Study Phase 45m
        Speaker: Yann Lechevin (CERN)
      • 2:15 PM
        Origins and framework of the ongoing Public Consultation Process within Host States 45m
        Speaker: Mattis Nil Madiane Kennouche (CERN)
    • 1:30 PM → 3:00 PM
      iRIS: Work programme presentation and alignment (ii) U3039

      U3039
      • 1:30 PM
        WP4 OpenSkyLab 30m
        Speaker: Prof. Marnik Denis Vanclooster
        iRIS-2605221421-MVC-WP4_Presentation_FCCWeek-V0005.pdf
        iRIS-2605221421-MVC-WP4_Presentation_FCCWeek-V0005.pptx
        WP4 FCC week
      • 2:00 PM
        WP5 Sustainability, impact and exploitation 30m
        Speaker: Johannes Gutleber (CERN)
        iRIS-2604301215-JGU-WP5_Kickoff_Presentation-V0100.pdf
        iRIS-2604301215-JGU-WP5_Kickoff_Presentation-V0100.pptx
      • 2:30 PM
        iRIS WP6 - Communication, Engagement and Inclusion 30m

        Large research infrastructures are central to scientific discovery, innovation and international collaboration, but their long-term sustainability depends not only on technical solutions, but also on trust, skills, visibility and uptake.

        This talk presents the communication, engagement and training work package of the iRIS project which ensures that the project’s results reach the communities that can use them, from research-infrastructure staff, industry, policymakers, educators, students to the general public.

        The talk will show how communication and training are integrated with stakeholder engagement, outreach, school and university activities, public demonstrations, industry days and media relations. By combining capacity building with measurable engagement and inclusive communication, this work package turns iRIS results into practical knowledge, strengthens public understanding of sustainable research infrastructures, and supports a lasting legacy through resources such as the Impact Transfer Handbook, connected with wider international efforts.

        Speaker: Carsten Peter Welsch (Cockcroft Institute / University of Liverpool)
        iRIS WP6 - CPWelsch.pptx
    • 3:00 PM → 3:30 PM
      Coffee break 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 3:30 PM → 5:00 PM
      Civil Engineering F3017

      F3017
    • 3:30 PM → 5:00 PM
      FCC-ee Accelerator: Synergies with other projects F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Catia Milardi (INFN e Laboratori Nazionali di Frascati (IT))
      • 3:30 PM
        Lessons learned from SuperKEKb (important for FCC-ee and Sudden Beam losses) 20m

        SuperKEKB is a circular collider with a 7GeV electron ring (HER) and a 4GeV positron ring (LER). Sudden beam loss (SBL) is one of the major problems faced by SuperKEKB, and various efforts have been made to solve it. Currently, we know that dust from the back seal is one of the causes. However, it seems that this is not the only cause and the problem is not completely resolved. This talk will introduce the current state of SBL and the path to solving the problem.

        Speaker: Dr HITOMI IKEDA (KEK)
        20260608FCCweek.pdf
        20260608FCCweek.pptx
      • 3:50 PM
        The US Electron-Ion Collider and its Synergies with FCC-ee 20m

        The Electron-Ion Collider (EIC) aims at a peak electron-proton luminosity of 10^34 cm^-2 sec^-1. We present the current design status of the facility and its synergies with FCC-ee.

        Speaker: Christoph Montag
        EIC-Montag.pdf
        EIC-Montag.pptx
      • 4:10 PM
        Study of the BEPCII upgrade to a crabbed-waist collider 20m

        IHEP is exploring potential schemes for BEPCII to adopt the crab-waist scheme to further increase luminosity and conduct relevant experimental research. Considering that BEPCII is an existing machine, the upgrade and modification must accommodate the existing tunnel geometry and detector spatial arrangement. It is preferable to make only local adjustments or modifications to the lattice. We plan to simultaneously modify both the collision region and the inner ring injection region of the existing BEPCII, aiming to compress the beta function at the interaction point from 1m/0.015m to 0.12m/0.005m or even lower. A pair of crab sextupoles will be installed before and after the IP. Additionally, an approximately 4-meter-long superconducting wiggler will be installed in the inner ring injection region. Following this approach, it is expected that crab-waist collision and a 10 times luminosity increase can be achieved in the 1.0 GeV to 1.89 GeV energy range while retaining the BESIII detector. By adding a compact damping ring to the linear accelerator, we also hope to achieve the physics operation in a new energy range below 1 GeV.

        Speaker: Dr Dou Wang (IHEP)
        BEPCII-UP_FCCWeek2026_wangdou-v3.pdf
        BEPCII-UP_FCCWeek2026_wangdou-v3.pptx
      • 4:30 PM
        CEPC MDI 20m

        The machine-detector interface (MDI) issues are one of the most complicate and challenging topics at the Circular Electron Positron Collider (CEPC). Comprehensive understandings of the MDI issues are decisive for achieving the optimal overall performance of the accelerator and detector. The machine will operate at different beam energies, therefore, a flexible interaction region design will be plausible to allow for the large beam energy range. The design has to provide high luminosity that is desirable for physics studies, but keep the radiation backgrounds tolerable to the detectors and other related sub system components. This requires careful balance of the requirements from the accelerator and detector sides.
        In this work, the latest design of the CEPC MDI and the study status of the beam induced backgrounds based on CEPC Technical Design Report (TDR) of the accelerator and the reference detector will be presented, covering the design of the beam pipe and whole IR, the estimation of beam induced backgrounds, the mitigating schemes, and also our plan towards the future study.

        Speaker: Haoyu Shi
        CEPCMDI_FCCWeek_20260609.pdf
    • 3:30 PM → 5:00 PM
      Joint effort PED & accelerators: EPOL (i) F3020

      F3020
      Convener: Alain Blondel (Centre National de la Recherche Scientifique (FR))
      • 3:30 PM
        Spin polarisation studies 22m
        Speaker: Yi Wu (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        FCC_week_2026.pdf
      • 3:52 PM
        Polarization transport to the collider ring 22m

        To be filled...

        Speaker: Jorg Wenninger (CERN)
        FCCee-InjectPol.FCC-week.JW.June2026.pdf
        FCCee-InjectPol.FCC-week.JW.June2026.pptx
      • 4:14 PM
        MONOCHROMATIZATION FOR FCC-ee OPTIMIZED PERFORMANCE STUDY AND FIRST ATTEMPT FOR IR OPTICS DESIGN FOR FCC-ee LCC LATTICE 22m

        Monochromatization is one of the most intriguing proposed operation modes of the FCC-ee, enabling a significant reduction of the centre-of-mass (CM) energy spread to a level comparable to the Higgs boson’s natural width produced through the s-mode direct channel at 125 GeV. Previous studies demonstrated its feasibility using earlier versions of the FCC-ee Global Hybrid Correction (GHC) optics. A first draft implementation of the scheme on the Local Chromaticity Correction (LCC) lattice is explored in this paper. The performances of the new optics types are presented in terms of luminosity and energy spread, supported by the simulation results. This provides an early outlook on the potential operational flexibility of future FCC-ee configurations operating in monochromatization mode.

        Speaker: Anna Korsun (Université Paris-Saclay (FR))
        monochrom_fccweek.pdf
      • 4:36 PM
        Spin tracking developments for insertion devices in XSUITE 22m

        Insertion devices with longitudinally periodic fields—such as undulators, damping wigglers, and polarizing wigglers—play a central role in several stages of the FCC-ee injection chain. Accurate field models and efficient long-term tracking are required, as the strong longitudinal field variation cannot be captured reliably with standard multipole expansions. We introduce in the Xsuite simulation toolkit a general model for such devices based on a Maxwell-consistent series expansion of the magnetic field. The expansion is constructed from the on-axis field and its transverse derivatives and is implemented in BPMETH, which provides a direct interface to Xsuite. Particle tracking is performed using the Boris integrator. We assess the approach by comparing Boris integration with a multipole expansion and compare the convergence of the resulting tracking. This framework enables detailed optics and beam-parameter studies for synchrotron light sources, damping rings, and polarization systems.

        Speaker: Simon Fanica Buijsman (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        Buijsman_Insertion_Devices_Xsuite_2026.pdf
        Buijsman_Insertion_Devices_Xsuite_2026.pptx
    • 3:30 PM → 5:00 PM
      Physics, Experiments and Detectors: Education, Communication, Outreach, Inreach F3005

      F3005
      Conveners: Claire Adam Bourdarios (CERN & CNRS / IN2P3), Panagiotis Charitos (CERN)
      • 3:30 PM
        Carte blanche to the CERN ECO group 20m
        Speaker: Arnaud Marsollier (CERN)
        FCC week Helsinki.pptx

        Communication around the FCC has come a long way—from early awareness-building to more structured, collective efforts. Today, we’re moving into a more strategic phase, with the need for a coordinated campaign, stronger media and digital presence, and more engagement to ramp up in the next months, not only local but also in all Member States and at global level, involving the wider community and our many partners.

        Building on the past experience from the LHC to the current local engagement and ongoing public debate, the next step is to shape a clear, impactful communication campaign—one that brings together storytelling, transparency, and dialogue to support the FCC in a complex and evolving context.

      • 3:50 PM
        Carte blanche to the FCC Earlly Career Professionals 20m
        Speaker: Armin Ilg (University of Zurich)
        The FCC Early Career Forum - Inreach in action.pdf
      • 4:10 PM
        The new PED ECOI Work Package 20m

        The FCC-PED organisational chart now includes a Work Package called ECOI, where the “I” stands for In-Reach, by analogy with the more familiar Out-Reach. The group’s structure, ambitions, and first deliverable — a fully updated website — are being presented to the FCC collaboration for the first time, with the goal of fostering feedback, new ideas, and broader participation.

        Speaker: Claire Adam Bourdarios (CERN & CNRS / IN2P3)
        PED-ECOI-ClaireAdam.pdf
    • 3:30 PM → 5:00 PM
      Systems Engineering and Project-wide integration F4050 Pieni Juhlasali

      F4050 Pieni Juhlasali
      • 3:30 PM
        Project Baselining, Configuration and Compliance control - strategy, implementation and challenges to achieve the Reference Design Phase deliverables 30m

        The FCC project relies on a project wide systems engineering framework to keep its pillars consistent as the design matures. The Systems Engineering and Project Integration (SEI) pillar activity in the FCC Project Office (FCC-PO) is responsible for this. Managing the project baselines (parameters, layout and specifications), the global integration model, configuration and change control, and compliance with project and Host States requirements.

        A first baseline was issued in March 2026 from the Feasibility Study configuration. This talk describes how the project moves from that baseline towards the end of the Reference Design Phase (RDP) through an organized configuration control process, and presents the main deliverables and milestones expected along the way, including the integration envelopes used to define space reservations and resolve interfaces between pillars.

        A large part of the work concerns compliance control, showing that the technical designs meet the high-level performance, functional, safety and regulatory requirements. The talk also introduces the project wide engineering specifications under development, such as the seismic design parameters, and the Engineering Change Request (ECR) process used to manage changes to the baselines.

        Speaker: Saruultugs Batzorig
        FCC_SEI_Baselining_Configuration_and_Compliance_control.pdf
        FCC_SEI_Baselining_Configuration_and_Compliance_control.pptx
      • 4:00 PM
        Safety Requirements at CERN: Framework, Background and Rationale 20m

        CERN, as an intergovernmental organization dedicated to fundamental research in particle physics, defines and implements its own Safety Policy to address the specific nature of its activities and installations and to ensure its proper functioning.
        For the implementation of the Safety Policy, CERN establishes and updates Safety Rules on the whole of its site. To this end, it takes into account the laws and regulations of the Host States, EU regulations and directives as well as international regulations, standards and directives. The Safety Rules established by CERN are deemed to fully cover the matter concerned whereas, in the absence of a CERN Safety Rule, the relevant laws and the regulations of the Host States apply on a territorial basis, thereby defining the regulatory framework at CERN.
        This contribution outlines the origins, structure and rationale of CERN’s Safety Requirements, explains their relationship with the overarching Safety Policy and Safety Rules, and highlights their role in ensuring coherent and effective safety concept for projects. The presentation also clarifies common misconceptions and highlights the implications for the FCC project.

        Speaker: Andre Henriques (CERN)
        FCC_week_2026_safety_requirements_AH.pdf
        FCC_week_2026_safety_requirements_AH.pptx
      • 4:20 PM
        Seismic Risk of FCC Underground Infrastructures - Preliminary Hazard Identification and Requirements for the Reference Design Phase 20m

        Complex research underground infrastructures, such as those of the FCC, often host tailored-made civil structures and specialized technologies and equipment. These non-conventional structures and locations are typically employed and do not adhere to standardised building codes or established procedures for seismic risk assessment. Nevertheless, earthquakes of sufficient magnitude may cause severe damage or equipment failures, posing substantial risks to personnel safety. Beyond those implicit to structural failures, these risks can be generated by potential cascading effects involving electrical, cryogenic and fire hazards.
        In order to establish suitable seismic safety requirements for the design of the structures, equipment and installations foreseen in the FCC underground facilities, CERN needs to define the hazard at the concerned soil depths. A coarse estimation of the seismic loads may lead to potential over- or under-size of the structural elements having, as a consequence, extra-costs or safety issues. To cope with such a problem, CERN established a collaboration with the Swiss Seismological Service (SED), hosted by the Swiss Federal Institute of Technology of Zurich (ETH), to preliminary determine seismic design requirements to be used in the Reference Design Phase of the FCC underground infrastructures and items foreseen in there. A normative approach compatible with the current Swiss building code and the upcoming new generation of the European Standards for the design of structures subject to earthquake loads is followed.
        The results of this study are presented in terms of seismic hazard curves, providing seismic intensity measures as a function of their annual rate of exceedance, as well as pseudo-acceleration response spectra at depth for several relevant locations and sectors of the FCC underground complex. The limitations of these results with respect to the FCC Technical Design Report phase are also discussed. Finally, perspectives and recommendations for future studies are outlined.

        Speaker: Marco Andreini (CERN)
        Andreini_et_al_FCC_week_2026_PB_MA_LD_MA.pdf
        Andreini_et_al_FCC_week_2026_PB_MA_LD_MA.pptx
      • 4:40 PM
        Mechanical Stability Challenges for FCC: Lessons Learned from LHC, HL-LHC and CLIC 20m

        The Future Circular Collider (FCC) will require unprecedented mechanical stability over a machine extending across nearly 90 km. Ground motion, technical vibrations, environmental perturbations, and seismic activity may significantly impact accelerator performance and operational reliability.
        This contribution presents lessons learned from vibration and stability studies performed at CERN in the context of LHC, HL-LHC and CLIC activities. The presentation will highlight measurement-driven approaches developed for realistic accelerator environments, including cryogenic systems, transfer function analyses, and ground motion characterization.
        The talk will also discuss the need for integrated FCC stability strategies combining infrastructure design, monitoring systems, operational mitigation, and emerging Digital Twin approaches.

        Speaker: Oscar Sacristan De Frutos (CERN)
        FCC_Week_Sacristan_v2.pdf
        FCC_Week_Sacristan_v2.pptx
    • 3:30 PM → 5:00 PM
      iRIS: Executive Board (closed session) U3039

      U3039
      • 3:30 PM
        Agenda (login required) 1h 30m
        iRIS EB#4
    • 5:00 PM → 6:00 PM
      Posters Main building

      Main building

      University of Helsinki

      Fabianinkatu 33, 00170 Helsinki
      • 5:00 PM
        Parametrization of Electron Cloud Buildup Models 1m

        We present an improved semi-analytical model for describing electron cloud (EC) buildup in particle accelerators. Macroparticle simulations show that EC density can be modelled as a smooth logistic-like curve with superimposed oscillations of a frequency corresponding to the beam bunch spacing. The saturation density and rate of electron cloud buildup can be linked to the best-fit parameters of the mathematical model chosen for the smooth curve. Our work investigates the dependence of each curve parameter on the simulation parameters, looking to reduce the number of simulations necessary to gain a complete picture of EC buildup per machine configuration. Correlations among the parameters can be utilized to formulate predictions using fewer data points. We investigate the dependence of our model parameters on secondary electron yield (SEY), bunch intensity, and photoemission. In addition, we develop an open source tool for electron cloud analysis which incorporates our modelling work.

        Speaker: Mr Adam Furman (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        FCC Week Poster.pdf
      • 5:01 PM
        Integrated HTS CCT Magnet and Beam Pipe : a Proposal for the FCC-ee Final Focus Quadrupole QCL1 1m

        High Temperature Superconductors (HTS) and Canted Cosine Theta (CCT) technologies have been extensively studied in recent years, particularly for high-field accelerator magnets. Their application to next-generation particle accelerators is especially promising. This article presents the combination of these two technologies for the FCC-ee Final Focus (FF) quadrupole QC1L/R1, including its integration within the Machine-Detector Interface (MDI).

        We detail the specific design, mechanical specifications, and manufacturing process—driven by the coil’s significant curvature angle—as well as the cryogenic test strategy and results. Additionally, we describe the design of a cooled beam pipe adapted to the magnet and cryostat constraints.

        Speaker: Matthieu Marchand (Centre National de la Recherche Scientifique (FR))
        Poster_FCCWeek2026.pdf
      • 5:02 PM
        Measuring RF Surface Resistance of Non-Evaporable Getter Coatings 1m

        A new method for measuring the RF surface resistance of non-evaporable getter (NEG) coatings has been developed at Daresbury laboratory. This method measures the surface resistance of tubular samples, meaning the pumping properties of the thin film can also easily be quantified and a full spectrum of NEG properties collected.
        In the design of future accelerators, it is important to maximise RF conductivity to prevent interruptions in the wakefield of the beam, which in turn would increase the energy spread of the beam.
        NEG coatings are vital to achieving the vacuum specifications required by accelerators, but can reduce the RF resistivity and thus are generally thickness limited to reduce the effect of the beam wakefields. With this new method RF surface resistance of different compositions and microstructures of NEG coatings can be investigated to find the ideal NEG coating specifications for both vacuum and RF conductivity properties.

        Speaker: Eleni Marshall (STFC Daresbury)
      • 5:03 PM
        New cryogenic test facility for FCC-ee SRF cavities at CERN 1m

        With the task of supporting the development of FCC SRF cavities, a new cryogenic facility is under development at CERN. The facility shall provide the possibility to test single cavities in full reflection mode fitted with FPC coupler, HOM couplers and operated at cryogenic temperatures for the actual baseline of the FCC accelerator: its development is focused on 400 MHz cavities, operated at 4.5 K, and 800 MHz cavities, operated at 2 K. Flexibility is required to accommodate in the same facility different cavities sizes and different coupler positions.
        With respect to similar facilities in other laboratories, the Horizontal Test Cryomodule (HTC) will take advantage of existing CERN infrastructures: its location has been identified with the M9 bunker of the SM18 test facility, already fitted with a valve box used for testing existing LHC and Isolde cryomodules.
        Simplified process diagrams, definition of design pressure and temperatures as well as the preliminary heat load evaluation are presented. Provisional sizing of cryogenic lines has been as well completed.
        A general overview of the cryomodule is then presented, with mention to the assembly procedures and to most relevant technical solutions implemented.

        Speaker: Luca Dassa (CERN)
        poster_dassa.pdf
      • 5:04 PM
        Impact of EMS Failures on FCC-ee beam 1m

        Failures in the electro-magnetic separator (EMS) system of the Future Circular Collider electron–positron collider (FCC-ee) can induce fast trajectory excursions with potentially critical impact on beam dynamics and machine components. This work investigates EMS failure scenarios and their consequences on beam trajectory and synchrotron radiation. Two main failure scenarios are considered: high-voltage breakdown leading to a complete loss of the electric field in an EMS unit, and partial magnetic field reduction due to power supply failure. Both cases result in a local mismatch of fields and generate transverse trajectory distortions. The EMS are installed before and after the RF cavities. Failures occurring upstream of the RF cavities can introduce a non-zero beam angle, leading to non-rectilinear trajectories within the cavities. This induces synchrotron radiation emission inside RF structures, potentially causing localized heat loads, radiation damage and inducing a trip of one or more cavities. Failures occurring downstream of the RF cavities can reduce the nominal deflection, compromising beam separation and propagating trajectory errors into the arcs. The resulting orbit distortions can lead to increased synchrotron radiation in bending regions, beam losses on aperture restrictions, and can create transverse instabilities. Mitigation strategies to minimise effects are discussed, including segmentation of the EMS into independent units and the use of high-voltage decoupling resistors to localize failures. These measures limit the impact of single events but do not avoid fast trajectory excursions, which must be addressed by dedicated machine protection systems. This study highlights the critical role of EMS reliability and failure mitigation in ensuring safe and stable FCC-ee operation.

        Speaker: Angela Potet
      • 5:05 PM
        RF Design of the compact RF power coupler for FCCee injector linacs 1m

        The high-energy linac of the Future Circular Collider electron–positron (FCC-ee) injector requires high-performance RF accelerating structures to efficiently reach 20 GeV with stable operation. A tapered travelling-wave structure operating at 3 GHz has been designed to optimize accelerating performance and suppress wakefields.
        This work focuses on the development of a full 3D model of the accelerating structure, including the RF power couplers, to ensure efficient power transfer and reliable high-power operation. Several coupling strategies were investigated to achieve a compact design while minimizing higher-order multipole components in regions lacking axial symmetry.

        Speaker: Pablo Martinez Reviriego
        FCC_couplers.pdf
      • 5:06 PM
        Updated RF Design and Optimization of 3 GHz Traveling-Wave Structures for the FCC-ee High-Energy Linac 1m

        The high-energy (HE) linac for the FCC-ee injector complex must deliver 20 GeV beams with high stability for top-up injection. Following an initial design at 2.8 GHz, the RF frequency has been updated to 3 GHz to align with the European S-band standard, enhancing compatibility with existing high-power RF components and industrial manufacturing for the Technical Design Report (TDR) phase.

        This work presents the updated design of 3 m traveling-wave (TW) accelerating structures operating at 3 GHz. A parametric optimization of the full structure geometry is performed, balancing effective shunt impedance and peak surface fields. Beam-loading compensation is applied via optimized RF pulse shaping for various bunch spacings. Detailed wakefield studies are conducted for various bunch spacings to ensure the transverse wake potential remains below the stringent 0.2 V/pC/mm/m threshold. Finally, tolerance studies quantify the sensitivity of wakefield suppression to manufacturing errors, establishing practical fabrication limits for the 3 GHz structures.

        Speaker: Pablo Martinez Reviriego
        IPAC_3GHz_structure.pdf
      • 5:07 PM
        Hybrid REBCO-Cu Coatings for the FCC Beam Screen: Achieving Low RF Surface Resistance and High Magnetic Field Homogeneity 1m

        Earlier findings from our consortium highlighted REBa₂Cu₃O₇₋ₓ (REBCO) coated conductors (CCs) as a promising alternative to copper for high-field radiofrequency (RF) applications in high-energy physics [1–2]. In this work, we demonstrate that commercial REBCO CCs provide the low surface resistance required for the Future Circular Collider (FCC) beam screen to operate at 50K or even higher temperatures. Using a Hakki–Coleman dielectric resonator, we show that REBCO significantly outperforms copper over a broad temperature range, up to 77 K, and magnetic fields reaching 16 T. Beyond material characterization, we report the successful integration of REBCO CCs as a coating for a beam-screen prototype. Our coating approach preserves superconducting performance on curved geometries while maintaining low surface resistance. A hybrid REBa₂Cu₃O₇₋ₓ/Cu coating is designed for the FCC-hh beam screen, satisfying both surface resistance and magnetic field homogeneity constraints [3–4]. Our analysis demonstrated that our hybrid REBa₂Cu₃O₇₋ₓ/Cu coating reduces the resistive wall beam impedance and satisfies the magnetic field quality criteria as compared to Cu in a real beam-screen configuration [5]. These results establish REBCO CCs as a promising candidate for next-generation FCC-hh beam screens.

        Speaker: Mr irfan ahmed
      • 5:08 PM
        Exploring Optimised Parameters of the FCC-ee Damping and Polarizer Rings 1m

        In the Z mode operation, the FCC-ee Damping Ring must deliver a sufficiently damped train of four bunches on every linac pulse. The damping rate depends on the beam energy, on the dipole magnets and additional wiggler magnets. The ring circumference determines the number of bunch trains stored in the ring, and, thereby, their store time. The parameters for the FCC-ee DR can be optimised, based on the requirements such as bunch storage for at least 5 vertical damping times, and which also include, as a new constraint, that the DR must have the same beam energy as the polariser ring. Particular focus is on the minimum or optimum energy of the damping ring.

        Speaker: Clara Marie Kiel (EPFL - Ecole Polytechnique Federale Lausanne (CH))
      • 5:09 PM
        Lifetime and sensitivity of Cherenkov-fibre beam loss monitors 1m

        Beam Loss Monitors (BLMs) are key components of machine protection systems in accelerators. In addition they provide key diagnostics for optimizing beam focusing and collimation.

        At the CERN Large Hadron Collider (LHC), over 3,600 ionization chambers (ICs) monitor loss profiles around magnets [1]. However, for the proposed Future Circular Collider (FCC-ee), the sensitivity of standard ICs is insufficient [2], and scaling the system would require an impractically large number of detectors.

        Radiation-induced Cherenkov emission in optical fibres provides a promising tool for high-speed loss detection. By coupling both ends of a fibre to silicon photomultipliers (SiPMs), the longitudinal position of a loss can be reconstructed. Fibre-based monitors can span up to 100 m [3], enabling coverage of large areas. Deployments at synchrotron facilities [4] and the Super Proton Synchrotron (SPS) demonstrate the operationability of this approach [5].

        Focus of our work is on material-dependent effects on detector sensitivity and on radiation tolerance. They will be implemented at the European Spallation Source (ESS) linear accelerator where their performance in high-radiation environments and capability of measuring loss profile in the dogleg of the accelerator is studied [6].

        We present the initial development of a fibre-based BLM system for ESS. Comparisons between Geant4 simulations and published benchmarks are shown with estimated photon yield and timing resolution realistic loss conditions. We also report on the experimental setup, including optical components and high-speed readout design, and outline the methodology for upcoming studies.

        [1] E.B. Holzer et al., Proc. IEEE NSS, 2005, pp.1052-1056.
        [2] M. Benedikt et al., Eur. Phys. J. ST 234, 19 (2025) pp.5713-6197.
        [3] M. Kalliokoski, S.Grishin, LHC-BLM-EC-0006.
        [4] P.J. Giansiracusa et al., Nucl. Instr. Meth. A 919 (2019) p.98-104.
        [5] S. Benitez, B. Salvachua, M. Chen, Phys. Rev. Acc. Beams 27 (2024) 052901
        [6] M. Eshraqi et al., Proc. IPAC2014, THPME043.

        Speaker: Dr Matti Kalliokoski (Helsinki Institute of Physics (FI))
      • 5:10 PM
        HTS Superferric Combined-Function Magnet for the FCC-ee Main Collider Ring 1m

        The baseline design of the FCC-ee main ring relies
        on thousands of separate resistive quadrupoles and sextupoles, ar-
        ranged in different combinations along its 90.7 km arc. However,
        this choice implies a substantial electrical power consumption
        due to the aggregate ohmic dissipation of normal conducting
        magnets. This paper presents an alternative design of a combined-
        function superferric magnet that aims to integrate quadrupole,
        sextupole, and dipolar fields within the same structure. The
        baseline design is based on a dodecapolar iron yoke, excited
        by High-Temperature Superconducting (HTS) racetrack coils
        operating at 30 K without liquid helium. We show that a three-
        power supply configuration is able to control and generate all the
        possible combinations of quadrupole and sextupole, at constant
        dipole. The design has been optimized on the configurations with
        maximum values maintaining at least 10K temperature margin
        on the HTS conductor. The quench-protection strategy at 30 K,
        the field-quality evaluation, and the mechanical design of a first
        prototype coil are also discussed. This work demonstrates that
        an HTS superferric combined magnet is a viable, power-efficient
        alternative to the resistive baseline for FCC-ee.

        Speaker: Simone Busatto
      • 5:12 PM
        Luminosity monitoring using Bhabha radiative electrons in SuperKEKB and FCC-ee 1m

        Bhabha radiative electrons are used to measure relative luminosity away from the IP. At SuperKEKB, this has been demonstrated using CVD diamond detectors at 4m from the IP. LGADs (Low Gain Avalanche Diode) have recently been tested as a potential alternative with the Lumibelle2 collaboration. This sensor has a much faster rise time, on the order of a nanosecond, but may be more susceptible to aging effects. The studies done on the LGAD can verify suitability of this detector in the FCC for fast luminosity measurements as well as benchmark studies against SuperKEKB for finding optimal positions for installation along the downstream beam pipe at each IP.

        Speaker: Pablo Mooney (The University of Manchester (GB))
      • 5:13 PM
        Physics Performance of the CEPC Reference Detector 1m

        The CEPC is proposed as a high-luminosity Higgs and electroweak factory, imposing stringent requirements on detector performance. The CEPC Reference Detector (TDR: https://arxiv.org/abs/2510.05260) has been assessed using full simulation and realistic reconstruction.
        Excellent performance is achieved for key physics objects, including high-efficiency tracking, precise vertexing, and multivariate-based particle identification. The particle-flow-oriented design enables accurate jet reconstruction, while advanced vertexing supports efficient heavy-flavor tagging. Physics benchmark studies, spanning center-of-mass energies from the Z pole to 240 GeV, demonstrate the capability to reconstruct complex final states and to perform precision measurements of Higgs and electroweak observables. These results establish the CEPC Reference Detector as a robust baseline for the CEPC physics program.

        Speaker: Chenguang Zhang (Chinese Academy of Sciences (CN))
        poster.pdf
      • 5:14 PM
        Hadron Flavour Tagging for $b$-hadronisation measurements at FCC-ee 1m

        The prospects for measuring $b$-hadronisation fractions at the FCC-ee Tera-$Z$ run are presented. Precise knowledge of the production rates of $B_c$, $B_s$, $B_u$, $B_d$, and $\Lambda_b$ hadrons is essential for heavy-flavour physics and for interpreting rare decay measurements. We develop an inclusive hadron flavour tagging approach to identify $b$-hadron species in $Z \to q\bar{q}$ events. The method exploits reconstructed particles and vertices at the hemisphere level to capture the decay topology, and is validated using exclusive decay modes to validation and calibration. This approach provides a direct handle on the $B_c$ hadronisation fraction $f(b \to B_c)$, which remains poorly constrained experimentally.

        Speakers: Vasilisa Guliaeva (EPFL - Ecole Polytechnique Federale Lausanne (CH)), Xunwu Zuo (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        FCCWeek2026Helsinki_hadrontagger_v2.pdf
      • 5:15 PM
        Physics sensitivity studies for $B_s^0\to\tau^+\tau^-$ searches at FCC-ee 1m

        This work presents the prospects for $B_s^0\to\tau^-\tau^+$ searches at FCC-ee. The standard model predicts that its branching fraction is $\mathcal{B}(B_s^0\to\tau^-\tau^+) = 7.73\times10^{-7}$. It is a highly sensitive probe to BSM but difficult to constrain in current experiments, the upper limit from LHCb being $6.83\times10^{-3}$. The fast simulated signal and inclusive $Z^0\to q\overline{q}$ background events are generated with the IDEA detector concept operating at the Z-pole. Different decay channels of $\tau^+\tau^-$ are studied. This contribution focuses on the $(3\pi)^+(3\pi)^-$ and $\ell^+\ell^-$ $(\ell=\mu/e)$. The analysis strategy consists in 3 steps, regardless of the channel used for signal identification: rectangular cuts, BDT models training and toy experiments fitting. The results are presented as per-channel sensitivity estimates. The $(3\pi)^+(3\pi)^-$ and $\ell^+\ell^-$ channels yielded sensitivity estimates of $8\times$ and $10\times$SM prediction respectively, while the combined fitting yielded a $6\times$SM estimate. More channels will be added in the future. An exclusive background survey is also presented.

        Speaker: Tobias Alexandre Monnard (EPFL - Ecole Polytechnique Federale Lausanne (CH))
      • 5:16 PM
        Full reconstruction of hadronically decaying tau leptons using ParticleTransformer 1m

        The large number of Z→ττ events expected during the TeraZ program at FCC-ee will allow for precision measurements and searches for physics beyond the Standard Model, requiring accurate reconstruction of hadronically decaying tau leptons. This reconstruction is particularly challenging due to the presence of undetected neutrinos and the diverse topology of hadronic tau decays. In this work, we present a machine learning based solution for the reconstruction of hadronically decaying tau leptons using the ParticleTransformer architecture. The reconstruction is formulated as a set of complementary tasks including tau identification, decay mode classification, charge reconstruction, and full four-momentum regression. The algorithms are evaluated on fully simulated electron-positron collision samples with realistic detector effects using the CLD detector setup. We study dedicated task-specific and unified multi-task reconstruction approaches, and evaluate their performance against conventional baselines for selected tasks. The presented approaches achieve strong performance across all reconstruction tasks and provide a realistic solution for hadronic tau reconstruction at future collider experiments.

        Speaker: Norman Seeba (National Institute of Chemical Physics and Biophysics (EE))
        mltau4_poster_v3.pdf
      • 5:17 PM
        A Key4hep Native Tracking Validation Tool for FCC-ee 1m

        We present a common tracking validation tool developed natively within the Key4hep ecosystem for FCC-ee reconstruction studies. The tool is implemented as a Gaudi Consumer in k4DetectorPerformance and is designed to provide consistent, configurable performance evaluation across different detector concepts, reconstruction algorithms, and software configurations.
        The algorithm runs at the end of the tracking reconstruction chain, consuming standard EDM4hep event data and digi-to-sim truth association links. It evaluates both track finding — quantifying efficiency and purity via hit-based majority-particle matching — and track fitting, computing residuals and resolutions for all five helix parameters with respect to both MC truth and an optional perfect-fitted reference. Summary performance observables, including d₀ resolution, momentum resolution, and transverse momentum resolution as a function of momentum, are produced automatically at the end of each run.
        The validation logic is fully independent of any specific detector implementation. Collection names are configurable via Gaudi KeyValues, and optional drift-chamber input is controlled by a single flag, allowing the same tool to run unchanged across different detector setups. The tool has been applied to both the IDEA and CLD detector concepts, producing consistent results and demonstrating its detector-agnostic design in practice.

        Speaker: Arina Ponomareva (Universita e INFN, Padova (IT))
      • 5:18 PM
        CERN beam test for the ALLEGRO TileCal-like HCAL 1m

        Highly granular calorimeters with fast response and large dynamic range are key elements of detector concepts for future colliders, where particle flow reconstruction is expected to significantly enhance physics performance. Optical sampling calorimeters are particularly attractive in this context due to their scalability, flexibility in segmentation, and robust performance.

        The ALLEGRO concept for FCC features a high-granularity sampling hadronic calorimeter (HCAL) based on plastic scintillating tiles. Similarly to the ATLAS Tile Calorimeter, the scintillating tiles are interleaved with stainless steel absorbers and the light produced is routed with wavelength shifter fibers to a photodetection system, which for FCC will be based on silicon photomultipliers (SiPMs).

        Significant progress has been achieved in detector design, electronics, calibration, and simulation studies within the ALLEGRO framework. In May 2026, a beam test of the ALLEGRO HCAL was carried out at the CERN PS East Hall (T10 beamline) using small-scale prototypes. The campaign focused on validating a multi-channel FERS-based readout system operated with external triggers, studying shower development in configurable steel–scintillator stacks, and characterising the light yield and response of different tile–fibre assemblies. The setup included multiple detector configurations with SiPM readout, as well as an online monitoring system to track data quality and detector conditions in real time. Data were successfully recorded with muons, electrons, and mixed particle beams, showing clear sensitivity to electromagnetic shower development and stable system performance.

        This contribution presents the experimental setup, data acquisition and monitoring strategy, and the first preliminary observations, providing key input for the optimisation of future large-scale prototypes and simulation models.

        Speaker: Ana Arranz Asensi (Univ. of Valencia and CSIC (ES))
        Testbeam_FCCTileCal_Poster.pdf
      • 5:19 PM
        Warm dark matter at the FCC 1m

        In this work, I study warm Higgs portal dark matter within the freeze-in at stronger coupling framework. A low Standard Model thermal bath temperature suppresses dark matter production, allowing for a significant dark matter-Higgs coupling. This opens the possibility of probing warm dark matter through Higgs decay at colliders such as the HL-LHC and FCC, which can explore a significant region of the parameter space. Constraints from Lyman-α observations are particularly strong and can further restrict the parameter space, guiding collider searches toward unconstrained regions.

        Speaker: Duarte Feiteira
      • 5:20 PM
        Dark photons in exotic Higgs boson decays at the FCCee 1m

        Hidden sectors possibly connected to dark matter, “dark sectors” are interesting physics Beyond the Standard Model (BSM) cases that arise in many different BSM theories and could naturally solve some of the biggest questions in particle physics. This poster explores one of such dark sectors, the vector portal mediated by dark photons, which will be accessible at the electron-positron stage of the Future Circular Collider, FCC-ee. A sensitivity study is performed for the scenario in which a Higgs boson decays to two dark photons that subsequently decay to two muons e+e−→Zh,Z→qqˉ,h→ZdZd,Zd→μ+μ−, Zd→μ+μ− . Since the dark photons interact very feebly, signals produced this way will often be long-lived and characterized by displaced dimuon vertices. The study is done using FCCAnalysis at a center-of-mass energy of 240 GeV. A signal grid is generated exploring phase space complementary to what is accessible at the LHC. A pre-selection based on the signal characteristics is designed and followed by a kinematic selection to remove background and further refine the signal discrimination. Finally, an estimation of the sensitivity for different available branching ratios of the Higgs boson is presented.

        Speaker: Sarah Ben Abdesselem (Uppsala University (SE))
        Dark_Photons_in_Exotic_Higgs_decays_at_the_FCCee_Poster.pdf
      • 5:21 PM
        Progress with superconducting thin film coated cavities at STFC Daresbury Laboratory 1m

        Superconducting thin film (TF) technology for SRF accelerating structures is applications is under intense development by the joint ASTeC–Lancaster University team at the STFC Daresbury Laboratory, aiming developing the UK’s capability in TF-SRF technology. Over last years, the team progressed from small sample production, surface science characterisation and basic superconducting properties measurements to an infrastructure allowing 1.3 and 6 GHz cavity preparation, coating with superconducting TF, superconducting properties evaluation with in-house developed methods and, finally, RF testing with low and high RF power at cryogenic facilities. This paper will describe the main facilities built at DL for superconducting TF deposition and characterisation on planar samples and RF cavities, cryogenic evaluation tests and RF testing infrastructure.

        Speaker: Dr Oleg Malyshev (UKRI/STFC Daresbury Laboratory)
      • 5:22 PM
        From Blue to Green: Characterisation of Novel Scintillating Fibres for Future Particle Trackers 1m

        Scintillating fibre (SciFi) trackers are a well-established technology for charged particle tracking in high-energy physics. Building on the successful operation of the LHCb Collaboration SciFi Tracker, this work investigates the potential of next-generation scintillating fibres for future collider detectors in the context of the Future Circular Collider (FCC).
        This poster presents an R\&D study comparing the performance of the currently used blue-emitting Kuraray SCSF-78 fibre with a new generation green-emitting scintillating fibre. The comparison focuses on several key properties relevant for detector applications: emission spectra, attenuation length, light yield, decay time, and radiation hardness.
        The study combines optical characterisation using spectrometer-based measurements with detector-oriented investigations employing SiPM readout systems and laboratory test setups. Particular attention is given to timing performance and light transport over long distances, which are critical parameters for large-area tracking detectors at future colliders.
        Beyond the FCC tracking context, the results also highlight recent developments in scintillating fibre technology and their potential relevance for a broader range of applications requiring radiation-tolerant, fast, and compact photonic detection systems.

        Speaker: Gauri Napoletano (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        NapoletanoGauri_poster_A0.pdf
      • 5:23 PM
        Development of the SciFi technology for tracking at Future Colliders 1m

        The scintillating fiber tracking detector technology (SciFi) has matured over the years, and its use cases have continued to expand. With recent technological advances, it is now possible to use SciFi as the main general-purpose tracker for future colliders. In this contribution, we present results on the performance of SciFi mats featuring a double-sided readout based on digital SiPMs, evaluated through simulation studies. We assess the achievable spatial and timing resolution and discuss the impact of the double-sided configuration on light yield collection and longitudinal position sensitivity. These results demonstrate the potential of SciFi technology to meet the demanding tracking requirements of future collider experiments such as those planned for the FCC.

        Speaker: Elena De Santis (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        ScifiposterHelsinki.pdf
      • 5:24 PM
        Full Optical Geant4 Simulation of the SciFi Tracker for R\&D for Future Colliders 1m

        The advent of Silicon Photomultipliers (SiPMs) has driven the widespread integration of Scintillating Fiber (SciFi) trackers across diverse detector designs. Building on previous efforts to model the SciFi tracker in Geant4, our team at EPFL has created a Geant4 framework capable of capturing it's full detector properties. In this contribution, we will be presenting the latest SciFi Geant4 framework, which simulates the tracker from initial scintillation to detection of all photons using a full optical simulation. The details of the simulation will be presented, showing its capabilities and flexibility for adaptation to different SciFi type detector prototypes, including the validation and the accuracy of the framework.

        Speaker: Dr Ismet Siral (EPFL - Ecole Polytechnique Federale Lausanne (CH))
      • 5:25 PM
        Chromatic calorimetry using nanocomposite wavelength-shifters 1m

        The development of advanced detector technologies will play a key role in the success of next-generation high-energy physics experiments, such as the Future Circular Collider (FCC-ee). Nanocomposite-based wavelength-shifters emerge as a promising technology for novel detector designs. These materials comprise quantum dots embedded in a polymer matrix, offering narrow, tunable emission spectra and fast timing capabilities.

        In the "chromatic calorimeter", a homogeneous electromagnetic calorimeter is longitudinally segmented using wavelength shifters, each layer featuring a distinct emission peak. A spectrally selective readout is then employed to separate the individual spectral components, enabling the reconstruction of the longitudinal shower profile.

        We report on recent advancements made with prototypes during beam tests conducted at the CERN SPS in 2024, 2025, and 2026. The initial proof-of-concept prototype utilized standard inorganic and organic plastic scintillators to establish benchmark performance, demonstrating stable operation and effective electron-pion discrimination. Building on these results, further prototypes incorporating nanocomposite wavelength-shifters were developed and tested. Results regarding shower profile reconstruction, energy calibration, and energy resolution are discussed and compared with Monte Carlo simulations performed in Geant4.

        Speaker: Greta Gajdan (Universitaet Bern (CH))
      • 5:26 PM
        Machine Learning Enables Real-Time Waveform Decomposition for Dual-Readout Calorimetry 1m

        Dual-readout calorimeters achieve superior energy resolution by simultaneously measuring Cherenkov and scintillation signals for event-by-event electromagnetic fraction correction, making them attractive for next-generation Higgs factories. However, if a full waveform readout is required for time-based analysis to separate Cherenkov and scintillation signals, high off-detector data rates might present challenges. These challenges can be mitigated by real-time signal processing in front-end electronics. We present a systematic comparison of machine learning (ML) and template fitting approaches for the separation of scintillation and Cherenkov light components in homogeneous dual-readout calorimeters across three representative crystal types. ML models achieve comparable signal extraction performance at lower sampling rates than template fitting. A single model trained over a range of incident particle energies demonstrates robust performance, and FPGA-compatible compression achieves latencies suitable for real-time application. This work establishes both baseline template fitting performance and ML-enhanced alternatives for crystal-based dual-readout calorimeters, offering practical pathways towards front-end feature extraction in future detector design.

        Speaker: Liangyu Wu (Stanford University/SLAC National Accelerator Laboratory)
        DRO_Algo_FCC_Week_2026.pdf
      • 5:27 PM
        Beam-Induced Backgrounds at FCC-ee: Occupancy Studies with IDEA and CLD using a Machine- and Detector-Agnostic Simulation Framework 1m

        Beam-induced backgrounds from beam-beam interactions pose a fundamental constraint on detector design at future $e^+e^-$ colliders, driving requirements on subdetector granularity, readout buffer depth, and front-end timing. We have developed a modular, parameter-driven simulation framework, built on the Key4hep software stack, that provides an end-to-end pipeline from beam-beam interactions through full Geant4/DD4hep detector simulation to per-layer occupancy and timing diagnostics.

        The framework accommodates alternative beam-beam generators and any DD4hep-compatible detector geometry available through k4geo. It was first validated through a comprehensive characterization of incoherent pair creation and hadron photoproduction backgrounds at the Cool Copper Collider (C$^3$) at $\sqrt{s}=250, 550$ GeV [Ntounis et al., JINST 21 (2026) P02024] and is now being extended to the FCC-ee.

        In this contribution, we will present the first end-to-end beam-induced background occupancy study carried out consistently across the Z-pole, ZH, and $t\bar{t}$ operating points of FCC-ee for both the IDEA and CLD detector concepts. Layer-level occupancy maps for the vertex and tracking systems will be presented alongside hit-timing distributions within a readout window, and results will be benchmarked against the occupancy targets commonly adopted in the literature. Preliminary results indicate that occupancies decrease with increasing $\sqrt{s}$​ and remain within the design targets with modest buffer depths.

        These studies deliver quantitative input to the ongoing optimization of the FCC-ee vertex and tracker subsystems, constraining pixel pitch, readout granularity, and buffer depth, and enable a first consistent comparison of the IDEA and CLD concepts. The framework further establishes a basis for extending the analysis to machine-detector-interface backgrounds such as beam-gas, beam halo, and synchrotron radiation.

        Speaker: Dimitris Ntounis (SLAC National Accelerator Laboratory (US))
        poster_BIB_FCCWeek2026_FINAL.pdf
      • 5:28 PM
        Impact of the ARC Detector on Particle Flow Reconstruction 1m

        The ARC detector is a compact RICH-based particle-identification concept proposed for future lepton-collider detectors. In the CLD detector concept, ARC is integrated between the tracking system and the electromagnetic calorimeter, introducing additional material upstream of the calorimeter and requiring compression of the tracking system. The present study does not yet exploit ARC particle-identification information, which is currently not available in the reconstruction, but focuses on the effect of the added material budget as a first step towards a full ARC performance assessment. In this study, we investigate the impact of this geometry modification on particle-flow reconstruction by comparing the baseline CLD_o2_v05 geometry to the ARC-integrated CLD_o3_v01 geometry. The comparison is performed using both PandoraPFA and the machine-learning-based HitPF reconstruction. We first quantify the direct geometry effects and observe broader calorimeter clusters, larger track-cluster displacements, and degraded tracking performance in the ARC geometry. To isolate the particle-flow impact from pure tracking effects, the main comparison is performed using GenTracking. The results show that charged-particle reconstruction remains largely stable, while the largest ARC-induced effects appear for photons and neutral hadrons. These effects are visible in clustering and PID efficiencies, fake rate, energy resolution, and event-level response distributions. Overall, the study indicates that the dominant reconstruction impact of ARC arises from neutral calorimetric reconstruction. More generally, it provides a quantitative case study for integrating dedicated PID systems into compact particle-flow detector concepts and identifies reconstruction optimization as a key ingredient for evaluating such detector-design choices.

        Speaker: Vincent Riechers (Universite de Geneve (CH))
        PF_ARC_poster.pdf
      • 5:29 PM
        CASSIA sensors for 4D tracking with fast timing 1m

        CASSIA (CMOS Active SenSor with Internal Amplification) is a proposed technology for 4D tracking with fast timing, where the focus lies on the development of pixel matrices with internal charge multiplication based on monolithic CMOS sensor technologies. The sensor is a novel MAPS which uses gain layers fully integrated in a 180nm imaging process to achieve internal signal amplification. Higher signal amplitudes lead to an improved signal-to-noise ratio, better time resolution and increased sensitivity. The monolithic integration in small pixels reduces the input capacitance of a front-end amplifier and power dissipation, making it suitable for fine-pitch low-power detectors. This contribution presents results from characterization of CASSIA sensors. The gain behaviour of different pixel implant designs is shown. The sensors can be operated in low gain proportional mode as LGAD sensors at lower voltages, and as SPAD sensor at higher voltages. First studies of the sensor from two different measurement campains in test beams will be presented.

        Speaker: Silke Mobius (Universitaet Bern (CH))
      • 5:30 PM
        Graph Neural Network Neutral Pion Identification for Noble Liquid Calorimetry Optimization 1m

        Separate prompt single photon electromagnetic showers from those arising from highly collimated photon pairs produced in boosted neutral pion decays is a critical capability for electromagnetic calorimetry, directly impacting both precision measurements and searches for new physics. This challenge is particularly relevant in the context of the electron-positron phase of the proposed Future Circular Collider, which will enable high precision studies of Standard Model processes as well as sensitivity to rare and beyond Standard Model signatures.
        This work focuses on the performance of the electromagnetic calorimeter of the ALLEGRO detector concept, currently based on a highly granular liquid Argon sampling technology, optimized for particle flow reconstruction and combining excellent energy resolution with stability, linearity, and uniformity.
        We present a novel approach to photon-neutral pion discrimination based on a Geometric Algebra Transformer architecture, a modern deep learning framework capable of exploiting the geometric structure of calorimeter data. The method is evaluated using the full simulation of the ALLEGRO electromagnetic calorimeter, demonstrating its ability to effectively separate overlapping electromagnetic showers from those promoted by single photons with different cross talk values and read out configurations. The results highlight the potential of this approach both for enhancing physics performance and for informing early-stage detector design choices for FCC-ee.

        Speaker: Jacopo Fanini (CERN & Université Paris-Saclay)
        20260609_TRAPPIST_poster.pdf
      • 5:31 PM
        Optimization Studies on the IDEA Muon System for Standalone Track Reconstruction at FCC-ee 1m

        Future electron–positron colliders such as the Future Circular Collider (FCC-ee) provide a clean environment for precision measurements and searches for physics beyond the Standard Model, including long-lived particles (LLPs). In this context, the muon system plays a crucial role in reconstructing highly displaced signatures that may not leave sufficient information in the inner tracking detectors.

        A comprehensive optimization study of the IDEA muon system design is presented, targeting efficient standalone reconstruction, especially for tracks originating from displaced vertices. A systematic parameter scan is performed by varying the number of detector layers, spatial resolution, lever arm, yoke thickness, and magnetic field strength. These studies are complemented by the development of an optimized reconstruction algorithm — the DisplacedTracking algorithm — designed specifically for the IDEA muon system and displaced tracks.

        The performance of each configuration is evaluated in terms of momentum resolution, reconstruction efficiency, fake rate, and vertex extrapolation capability. It is found that increasing the number of layers and lever arm significantly improves momentum resolution and efficiency, while improving spatial resolution does not. The interplay between detector geometry and reconstruction strategy is shown to be essential for achieving better performance in sparse-hit-per-track environments.

        The impact of the various designs is assessed using a benchmark Heavy Neutral Lepton (HNL) scenario with a mass of 20 GeV and a coupling to muons of $10^{-5}$.

        These findings provide important guidance for the design of the IDEA muon system and highlight the importance of co-optimizing detector geometry and reconstruction algorithms for long-lived particle searches at FCC-ee.

        Speaker: Mahmoud AlThakeel (CERN)
        FCC_Week_poster3.pdf
      • 5:32 PM
        Investigation of Time Projection Chamber Technology at the Z Pole for Future e+ e- Colliders 1m

        The Circular Electron Positron Colliders (FCCee and CEPC) were proposed as the Higgs and Z operation in High Energy Physics communities. In the ILD detector concept, as well as in comparable detector designs, the baseline detector design features a high-precision (approximately 100 μm) spatial resolution Time Projection Chamber (TPC) as the main tracking device surround a 3.0T solenoid field. The TPC is required to provide a standalone momentum resolution of 10^{-4} (GeV/c)^{-1}, and the physics requirement of Particle Indentification (PID) resolution should be reached less than 3%. TPC performance is satisfactory in Higgs mode, but high luminosity Z pole running poses substantial technical challenges requiring rigorous evaluation of feasibility and mitigation strategies.
        In this talk, the feasibility and update progress of high precision TPC as the main track detector for e+ e− collider will be presented. TPC detection aims the good separation power with the cluster counting to be considered and the simulation results of the pad/pixelated TPC technology for e+ e− collider will be given. Compared with the pad readout using the simulation, the high granularity readout TPC option (500μm × 500μm) will obtain the better spatial resolution of single electrons, the very high detection efficiency in excellent tracking and good PID performance (less than 3σ). Based on MDI background simulation data to study ion-induced space charge effects, we have conducted a detailed assessment of TPC technical challenges and potential solutions, particularly under low luminosity Z pole running conditions.

        Speaker: Huirong Qi (Institute of High Energy Physics, CAS)
      • 5:33 PM
        Status of "turbine" NL EM endcap calorimeter for ALLEGRO 1m

        A status report on the "turbine" style noble liquid EM endcap calorimeter concept for the ALLEGRO detector will be presented. Specific topics will include studies of the optimal segmentation, updated mechanical studies, and the status of tests of the prototype readout board.

        Speaker: Erich Ward Varnes (University of Arizona (US))
      • 5:34 PM
        The Belle II LS2 upgrade 1m

        The run 2 of the Belle II experiment at the SuperKEKB collider in Tsukuba (Japan) is expected to last until 2031. For the long-shutdown 2 (LS2) in 2032-33 an upgrade plan for the machine and the detector is currently being developed: The final focusing QCS magnets will move 10 cm closer to the IP requiring the construction of a new vertex detector. The inner layers of the drift chamber will have accumulated a charge in excess of 1000 mC/cm and will have reached their end of life.

        In this presentation I will review the work towards the Belle II LS2 upgrade TDR. This upgrade includes a 5 layer VTX vertex detector based on active CMOS pixel sensors and a new drift chamber with reduced inner radius. The gap between these two subsystems will be filled by an LGAD-based ps-timing layer and a tracking layer using active CMOS strip sensors. Lessons learned for a future $e^+e^-$ detector will be highlighted.

        Speaker: Christoph Schwanda (Austrian Academy of Sciences (AT))
        poster_fcc2026.pdf
      • 5:35 PM
        Overview of FCC-ee MDI activities at SLAC 1m

        SLAC is pursuing a number of activities related to machine detector interface (MDI) design, engineering, and performance. These activities include a mockup of the QC1 cryostat, a mockup of services for the vertex and LumiCal detectors, and modeling beam-induced backgrounds with the high performance particle-in-cell (PIC) code WarpX. We provide a timeline for these activities consistent with delivery of the Reference Design Report in 2028.

        Speaker: Spencer Gessner
      • 5:36 PM
        Laser-based collimation and control of particle beams 1m

        Laser-driven Compton backscattering (CBS) has been proposed as method for controlling the intensity of colliding bunches in the FCC-ee so as to avoid the flip-flop instability caused by intensity asymmetry in colliding bunches. Laser-based collimation has also been proposed as an indestructible collimator for high-intensity electron beams. We have initiated a laboratory-based test program of these concepts with the E344 experiment at FACET-II. We describe simulations of laser-beam interactions at FACET-II and the relevant scaling for FCC-ee. We also describe the experimental setup and diagnostics that will be used to make the measurements at FACET-II.

        Speaker: Spencer Gessner
      • 5:37 PM
        WarpX: a massively parallel PIC framework for future colliders 1m

        Particle In Cell (PIC) codes are a key tool for performance optimization of future colliders, notably the FCC-ee. They are used to study beam-beam effects, luminosity, beam background, machine protection and lifetime. The most frequently used open source PIC codes by the collider community (GUINEA-PIG, Xsuite) are not optimized for configurations with a large Piwinski angle, relevant for FCC-ee, which require large scale parallelization or the optimization of the static 3D grid to overcome the computational bottleneck. This contribution will present WarpX, a multi-purpose PIC framework, featuring mesh refinement and multi GPU parallelization with domain decomposition. This tool has recently been extended with collider relevant features (QED backgrounds, luminosity, crab-waist scheme, crossing angle) and we aim to present it as an alternative to the currently used tools. We show first results of benchmarking FCC-ee luminosity and radiation spectra against GUINEA-PIG, and demonstrate the feasibility of multi turn tracking simulations by coupling WarpX with Xsuite.

        Speaker: Peter Kicsiny (SLAC)
      • 5:38 PM
        Luminosity Loss from Ground Motion in the FCC-ee: MDI and Arc Quadrupole Vibration Studies 1m

        Ground motion can significantly impact beam stability in the FCC-ee, potentially degrading luminosity at the interaction point (IP). The study models vibrations of accelerator components, including the interaction region cryostats at the Machine Detector Interface (MDI) and the quadrupole girders in the arcs. Using measured power spectral densities (PSDs) and component-specific transfer functions, realistic time-dependent displacement signals are generated and applied in Xsuite particle tracking simulations. Analysis of beam centroid motion at the IP and the relative transverse offset between colliding beams quantifies the resulting luminosity degradation. These results indicate that ground-induced motion may necessitate dedicated feedback systems for both orbit correction and luminosity stabilization. Findings inform the design of vibration mitigation strategies and feedback strategies for the FCC-ee.

        Speaker: Mael Le Garrec (Laboratoire d'Annecy de Physique des Particules (CNRS IN2P3-LAPP))
      • 5:39 PM
        FCC-ee Integration Requirements for Injection-Extraction Equipment 1m

        The recent LCC optics choice has contributed to Accelerator Beam Transfer (ABT) equipment being repositioned and as this directly impacts the integration aspects and therefor cable lengths a new study is conducted.
        This work provides an overview of integration and space requirements for fast pulsed kicker magnets, septa and their power converters and controls for the FCC-ee booster and collider injection, extraction and dump systems.
        The position of the kickers, septa in the tunnel is defined by the optics, then their technology selection is based on the required pulse parameters.
        The technology selection governs the choice of adequate power convertor which ensures the right pulse form and voltage to correctly manipulate the beam.

        Speaker: Dylan Standen (CERN)
        FCC Week Poster - FCC-ee Integration Requirements for Injection-Extraction Equipment 2026.pdf
      • 5:40 PM
        Standardised Lumped Inductance Kicker Magnet for the FCC-ee 1m

        CERN is currently developing the Future Circular Collider (FCC-ee), a next-generation accelerator complex with a 90.7 km circumference. This poster explores the technical challenges inherent in beam-transfer equipment, specifically regarding the kicker systems from Booster extraction to Collider dump. To reduce the diversity of beam-line components and standardize hardware parameters, this work proposes a modular lumped-inductance kicker magnet suitable for multiple systems. The required deflection for different systems is achieved by simply adjusting the number of modules. Furthermore, each module operates at a limited voltage, enabling the equipment to function outside of the vacuum, simplifying the design and thus minimising the cost. The poster presents initial results from numerical simulations of the beam-line element, alongside various system-level design options for use within the FCC-ee accelerator.

        Speaker: Grigorios Sergentanis
      • 5:41 PM
        Impedance mitigation and design guidelines for the FCC-ee collimation system 1m

        The FCC-ee collider in the Z configuration, operating at 45.6 GeV, is particularly sensitive to impedance-driven collective effects. The collimation system is among the dominant contributors to the machine impedance budget, making its optimization crucial for stable operation. This work investigates the impact of collimator jaw length on wakefields and beam dynamics. The results show that shorter jaws reduce the impedance contribution and increase the instability threshold. However, the improvement progressively saturates below a critical length, beyond which further reductions provide only marginal gains. These findings identify an optimal design region and provide practical guidance for the impedance optimization of the FCC-ee collimation system.

        Speaker: Dora Gibellieri (University of Caen Normandy)
        FCCweek26_Gibellieri_poster.pdf
      • 5:42 PM
        Fire detection technologies for FCC tunnel 1m

        The future fire detection system for the FCC tunnel will be adapted to non-standard environmental constraints. The large surface area to be protected, the presence of radioactivity, and the long distance between alcoves that can house standard electronics are among the most significant constraints. The current baseline solution relies on smoke detection by air sampling, with a similar system to the one deployed on the SPS accelerator. An alternative solution based on thermal detection technology is being considered. Selection criteria such as effectiveness, cost, maintainability, availability and integration must be taken into account. An ongoing study aims to determine the optimal solution.

        Speaker: Michael Dole (CERN)
        EDMS_3466608V1_FCC_Week_2026_Poster_Fire_detection.pdf
      • 5:43 PM
        Black-Box RAG system evaluation pipeline 1m

        Evaluating production RAG systems poses a fundamental challenge: internal retrieval logic, prompt templates, and model decisions are typically inaccessible, yet systematic quality assurance is essential prior to deployment and throughout a system's lifecycle. This work presents a modular, black-box evaluation pipeline developed in the context of the FCC communication chatbot, a multilingual conversational system supporting public outreach and information dissemination for the Future Circular Collider.

        The pipeline operates exclusively on observable system behavior, namely questions, answers, and retrieved context passages, without requiring access to internal components. It is structured into six independent evaluation layers: live trace collection (L0), embedding-based semantic drift detection (L1), grounding assessment using RAGAS-derived metrics (L2), failure diagnosis via ensemble LLM-as-a-judge evaluation (L3), reference correctness scoring (L4), and cross-lingual robustness analysis (L5). This layered design enables dimension-specific diagnostics, allowing operators to distinguish retrieval failures, generation hallucinations, and cross-language inconsistencies rather than relying on a single aggregate score.

        Failure diagnosis and correctness scoring leverage an ensemble of independent LLM judges running on distinct models, reducing single-model bias and providing a built-in confidence signal through inter-judge agreement rates. All evaluation prompt templates are versioned, ensuring full reproducibility across pipeline runs.

        Designed to remain applicable across backend changes, including different models, architectures, or vendor implementations, the pipeline provides a reusable quality assurance infrastructure for any RAG-based system. The framework is openly documented and integrated into CI/CD workflows for continuous monitoring.

        Speaker: Francesco Pinzauti (CERN)
      • 5:44 PM
        Unveiling Light-Quark Yukawa Flavor Structure via Dihadron Fragmentation at Lepton Colliders 1m

        Directly probing light-quark Yukawa couplings and their flavor structure remains a major challenge due to their smallness and overwhelming QCD backgrounds. In this talk, we propose a theoretical framework to access these couplings at lepton colliders through transverse spin dependent azimuthal modulations in dihadron fragmentation. These modulations arise from the interference between Higgs mediated and Standard Model amplitudes in $e^-e^+\to q\bar{q}Z$, producing angular structures that are linearly sensitive to the Yukawa couplings $y_q$, in contrast to conventional observables that scale as $y_q^2$. By combining channels with an identified accompanying single hadron, $h^\prime=\pi^\pm,K^\pm$, and $p/\bar{p}$, this approach cleanly disentangles the up- and down-quark Yukawa contributions, yielding typical limits at the $\mathcal{O}(10^{-4}\sim 10^{-3})$ level and establishing fragmentation dynamics as a novel and complementary probe of the Higgs flavor structure.

        Speaker: Mr Xin-Kai Wen
      • 5:45 PM
        Update on the FCC IR HOM Evaluations 1m

        We present the latest results of electromagnetic calculations regarding the interaction of the high-intensity beam field with the metal walls of the FCC-ee interaction region beam pipe. This interaction generates a thermal load on the beam pipe walls, which degrades vacuum conditions and can increase the background. We have improved our calculation methodology to evaluate the heat load for proposed materials. Furthermore, we analyzed how coating the beam pipe with alternative materials can reduce this heat load or improve vacuum performance. Calculations were performed using FCC-ee beam parameters across different energy stages: Z, WW, H(ZH), and ttbar.

        Speaker: Dr Alexander Novokhatski (SLAC National Accelerator Laboratory)
      • 5:46 PM
        Watts per Event: Sustainable HIJING++ Heavy-Ion Monte Carlo Generation for the FCC Era 1m

        The computing demands of the FCC era will exceed those of the HL-LHC by an order of magnitude, with Monte Carlo (MC) event generation persistently consuming the majority of the available CPU budget. For a future heavy-ion programme, where AA event generation is nearly an order of magnitude more expensive per event than pp, the energy cost of generator tuning campaigns risks becoming a limiting factor for the physics reach. As global hardware prices rise and the community moves toward carbon-aware computing, the success metric for MC production must evolve from raw throughput to sustainable efficiency — energy spent per generated event.

        We present a reproducible framework for evaluating and reducing the energy-per-event of MC generation, built around HIJING++, a C++ multithreaded heavy-ion generator. The proripy Docker image bundles HIJING++, PYTHIA 8, Rivet, YODA, HepMC3, and Professor together with a benchmarking pipeline that correlates wall-clock throughput with measured CPU package power, yielding a sustainability score $E_{event} = P_{avg} / T_{event}$, in the same throughput-per-watt spirit as HEPScore23.

        We close with HIJING++ tuning results for FCC-hh and based on ALICE pseudorapidity distributions (0.9–13 TeV) obtained inside the toolbox, and discuss implications for sustainable heavy-ion generator development toward FCC.

        Speaker: Dr Gergely Gabor Barnafoldi (HUN-REN Wigner Research Centre for Physics (HU))
        fcc_week_2026_hijing_poster_BG.pdf
      • 5:47 PM
        Track finding 1m

        Track finding — grouping detector hits into charged-particle trajectories — is traditionally detector-specific and costly to adapt to the new detector concepts proposed for the FCC-ee. Classical combinatorial methods rely on hand-crafted seeding and a detailed detector description, while many machine-learning approaches depend on edge prediction or external density clustering. To bridge these gaps, in this study we introduce CIRCE (Conformal-algebra Instance Reconstruction by Condensation Embedding), an equivariant geometric-algebra transformer that processes all hits in an event jointly. Its key design choice is to represent every hit as a multivector in the conformal geometric algebra Cl(4,1) rather than the projective algebra Cl(3,0,1): whereas the latter encodes only points, lines and planes, the conformal algebra natively embeds circles and spheres, so silicon vertex hits become null points and drift-chamber measurements become drift circles. To our knowledge, CIRCE is therefore the first track finder to process point and circle hits jointly within a single equivariant model. For each hit, the network predicts a clustering embedding, a condensation score β, and a noise probability; at inference, β drives track reconstruction directly — high-β hits seed tracks, duplicate seeds are removed by non-maximum suppression, and the remaining hits are assigned to the nearest seed — so no external clustering algorithm is required. We evaluate CIRCE on the FCC-ee IDEA detector concept with simulated e+e- → Z → qq̄ events and benchmark it against the current state-of-the-art tracking model reporting tracking efficiency, purity and fake rate. Our model can be also exported to C++ compatible format for in-place replacement of current models in tracking programs.

        Speakers: Andrea De Vita (CERN & Università di Padova), Brieuc Francois (CERN), Dolores Garcia (CERN), Marko Cechovic
    • 6:30 PM → 7:15 PM
      FCC Early Career Forum F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Conveners: Armin Ilg (University of Zurich), Jacqueline Keintzel (CERN)
  • Wed, June 10
    • 8:30 AM → 10:00 AM
      Accelerator Technical Design: Magnets F3017

      F3017
      Convener: Rhodri Jones (CERN)
      • 8:30 AM
        Status of the functional specification of the collider magnets and plan of prototypes 20m

        We will summarize the arc magnet functional specification and designs proposed for the updated LCC optics baseline, together with the prototypes plan for the Reference Design Phase.

        Speaker: Ignacio Garcia-Aguirrebeitia Sanchez (CERN)
        FCC_Week_2026_FCC-ee_-_Status_of_the_Functional_Specification_of_the_Collider_Magnets_and_Plan_of_Prototypes_20260602.pdf
        FCC_Week_2026_FCC-ee_-_Status_of_the_Functional_Specification_of_the_Collider_Magnets_and_Plan_of_Prototypes_20260602.pptx
      • 8:50 AM
        Tolerance and sensitivity analysis of FCC-ee collider magnets 10m

        We assess the impact of manufacturing-induced uncertainties on the magnetic field quality of FCC-ee collider dipole and quadrupole magnets. The methodology considers both material and geometric uncertainties, which are propagated using probabilistic methods through computational models. To enable efficient uncertainty quantification, surrogate models are developed and validated against high-fidelity finite element simulations. For both magnet types, the most critical relative field harmonics and their associated systematic and random errors are identified. In the case of the dipole magnet, material and geometric uncertainties are investigated and shown to be independent, allowing them to be treated separately. The predicted field quality is compared with measurements obtained from a prototype magnet. For the quadrupole magnet, the most critical assembly parameters are identified, and their contribution to relative field errors is quantified through sensitivity analysis and probabilistic uncertainty propagation. The resulting systematic and random field errors provide valuable input for beam dynamics and tuning studies, while also supporting the definition of manufacturing tolerances, assembly procedures, and magnet optimization for FCC-ee collider magnets.

        Speaker: Luka Todorovic (Technische Universitaet Wien (AT))
        Tolerance_Analysis_Todorovic.pdf
        Tolerance_Analysis_Todorovic.pptx
      • 9:00 AM
        The collider sextupole magnet prototype 15m

        This work presents the electromagnetic and preliminary mechanical design of the sextupole magnet for the FCC-ee collider. The original design, based on the GHC optics requirements, has been revised to comply with the new baseline - LCC optics. Detailed 2D and 3D magnetic simulations were performed to optimize the magnet parameters. The results confirm that the proposed sextupole design fully meets the beam optics requirements. To experimentally validate the design parameters, the fabrication of a prototype is planned in frame of a collaboration between CERN and Chiang Mai University, Thailand. Prototype manufacturing approaches and the production milestones are presented and discussed.

        Speaker: Supasin Sukara (Chiang Mai University (TH))
        FCC-week2026-Sextupole magnet.pdf
        FCC-week2026-Sextupole magnet.pptx
      • 9:15 AM
        Status of the booster magnets for FCC-ee 15m

        This presentation reviews recent progress in the development of the High Energy Booster (HEB) magnet system. Updates to the designs of the main dipole, quadrupole, and sextupole magnets are presented to address the revised booster optics requirements resulting from changes to the collider optics. Results from the dipole prototyping campaign are reported, including measurements of a second short dipole prototype manufactured using a different steel grade. These measurements, together with those obtained from the first prototype, enable an assessment of the impact of steel selection and ramping effects on dipole performance. The completed design and ongoing manufacturing of a prototype focusing sextupole based on automated winding technology are also presented. Finally, future directions for magnet system development during the reference design phase are outlined.

        Speaker: Luke Von Freeden (CERN)
        20260610_FCC_week_2026_booster_magnets.pdf
        20260610_FCC_week_2026_booster_magnets.pptx
      • 9:30 AM
        Magnetic measurements for FCC-ee magnets 15m
        Speaker: Mariano Pentella (CERN)
        MPentella - FCC_Week_2026.pdf
      • 9:45 AM
        The required technological development for the FCC-ee magnets – A summary 15m
        Speaker: Mr Melvin Liebsch (CERN)
        090629_FCC-ee-tech_dev_report_2.pdf
        090629_FCC-ee-tech_dev_report_2.pptx
    • 8:30 AM → 10:00 AM
      Environment F2044 Auditorium

      F2044 Auditorium
      • 8:30 AM
        Summary of FCC environmental matters as presented in the DMO 30m
        Speaker: Mrs Sophie Valette (HSE Unit)
        FCC-2605181645-SVA_FCC_Environmental_topics_DMO_v0004.pdf
        FCC-2605181645-SVA_FCC_Environmental_topics_DMO_v0004.pptx

        This contribution provides an overview of the environmental considerations outlined in the project owner's file, which was drawn up as part of the public consultation process that has begun in the Host States. It also provides an update on work currently underway and planned for the coming years.

      • 9:00 AM
        Current status of environmental investigations for the injector in Prévessin and next steps 30m

        The presentation discusses the role of early ecological investigations in supporting the development of the FCC injector baseline at the CERN Prévessin site. It explains why ecological studies are essential at an early stage, not only to describe the existing environment, but also to identify ecological and regulatory sensitivities that may influence future design decisions.
        The presentation summarises the 2025 preliminary ecological diagnostic, including the inventoried area, the main environmental components assessed, and the methodology used to establish ecological sensitivities. It also presents the ongoing complementary investigations, their expected outputs, and how the results will contribute to an updated ecological baseline, GIS layers and environmental sensitivity grid.
        It highlights that environmental information should be integrated from the start as a design and risk-management input, helping reduce uncertainty and support future refinement.

        Speaker: Patrycja Laidouni (CERN)
        FCC-260527143PLA-FCCWeek2026_Presentation_EnvironmentalStudiesPrevessin_V0100.pdf
        FCC-260527143PLA-FCCWeek2026_Presentation_EnvironmentalStudiesPrevessin_V0100.pptx
      • 9:30 AM
        Status update on OpenSky Lab 30m
        Speaker: Christiana Staudinger (University of Natural Resources and Life Sciences (BOKU) (AT))
        FCC-OSL-2605261330-CST-FCCWeek26_V0100.pdf
        FCC-OSL-2605261330-CST-FCCWeek26_V0100.pptx
    • 8:30 AM → 10:00 AM
      FCC-ee Accelerator: Collective Effects F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Mauro Migliorati (Sapienza Universita e INFN, Roma I (IT))
      • 8:55 AM
        Interaction region impedance study 15m

        This contribution presents an ongoing coupling impedance study of the interaction region (IR) for the FCC-ee collider, with a focus on power loss and beam-induced heating in the vacuum chamber.
        The IR design, consisting of the intersection of four beam pipes, is characterized by transitions between round and elliptical cross-sections; despite the smooth geometry designed to minimize the beam coupling impedance, some electromagnetic modes remain trapped in the vacuum chamber. Due to the resistive wall wakefields and to modes excited by vacuum chamber discontinuities, the high-current beams foreseen for FCC-ee may lead to significant beam-induced heating.
        The current status of the study is presented, and results are discussed for the main IR elements, including the central beam pipe, the ellipto-conical vacuum chambers connecting it to the two symmetrical beam pipes, and the static masks that are part of the synchrotron radiation (SR) collimation system. Particular attention is given to the evaluation of power loss in the presence of two counter-rotating beams. Moreover, the challenges due to the geometrical complexity and length of the IR are discussed.
        The study also identifies the dominant contributions to the impedance budget, advancing the development of a consistent FCC-ee impedance model and supporting the optimization of the IR design for stable and efficient collider operation.

        Speaker: Elena Macchia (Sapienza Universita e INFN, Roma I (IT))
        260610_FCCWeek2026_IRImpedanceStudy_Macchia.pdf
        260610_FCCWeek2026_IRImpedanceStudy_Macchia.pptx
      • 9:10 AM
        Electron Cloud Buildup Modelling and Photoelectron Studies 15m

        The buildup of electron clouds (EC) within the beam chamber limits machine performance by causing beam instabilities and other undesirable effects. In this work, we study parametrizations of EC buildup, as well as the impact of photoemission from synchrotron radiation. The buildup of an electron cloud can be modelled as a smooth, logistic-like curve described by three parameters accounting for the saturation density of the electron cloud, the buildup rate, and the rate of photoemission of electrons from synchrotron radiation. Our work investigates the dependence of each curve parameter on the simulation parameters, looking to reduce the number of simulations necessary to gain a complete picture of EC buildup per machine configuration. Correlations among the parameters can be utilized to formulate semi-analytical predictions. We also investigate the role of the synchrotron radiation flux distribution around the beam chamber, using realistic radiation profiles and magnetic field configurations. We find no significant impact on electron cloud saturation density from nonuniform as compared to uniform radiation distributions. However, we see a consistent discrepancy between our results and existing theory regarding the impact of photoelectrons on EC buildup, potentially pointing to the need for more detailed models.

        Speaker: Mr Adam Furman (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        FCC Week Presentation.odp
        FCC Week Presentation.pdf
      • 9:25 AM
        Interaction Point Challenges: Feedback, Solenoid Compensation, and SuperKEKB Benchmark 20m

        Achieving the target luminosities of FCC-ee requires tight control of the beam orbits and optics at the IP. Important challenges include orbit distortions from machine errors and the coupling and optics perturbations introduced by strong experimental solenoids. This presentation discusses the current status of IP feedback and solenoid compensation schemes for FCC-ee, using experience from SuperKEKB as a benchmark for feedback implementation in a high-luminosity collider environment.

        Speaker: Mr John Patrick Salvesen
        interaction_point_challenges.pdf
      • 9:45 AM
        Interaction Point Aberration Tolerances from Beam-Beam Simulations 15m
        Speaker: Vaibhavi Gawas (CERN / University de Geneve)
        IP_Aberrations_FCCWeek_VG-7.pdf
    • 8:30 AM → 3:00 PM
      Industry Day F3020

      F3020
    • 8:30 AM → 10:00 AM
      Physics, Experiments and Detectors: Physics Software and Computing F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Convener: Gerardo Ganis (CERN)
      • 8:30 AM
        Towards an FCC Computing Model 18m

        FCC distributed computing is advancing toward a WLCG-like model to meet the challenges of planning for a collider 15 years away. Long procurement cycles for data centres and rapid technology shifts mean we must start planning now.
        We currently consolidate our community by adopting CERN Tier 0 resources (SWAN, lxbatch, ml.cern.ch, dedicated computing nodes) while evolving toward distributed access to external resources (WLCG sites, EuroHPC, clouds), reusing DIRAC (workloads), Rucio (data), and CVMFS (software).
        We aim to analyse the computing requirements associated with the Z peak operation phase of FCC‑ee.
        While planning, we must assess how the WLCG model will interact with centralized high-density facilities such as AI factories, how to secure sustained EU funding for HEP infrastructure and beyond, and how computing technologies like accelerators will evolve. As a pre-FCC effort without live DAQ constraints, we can help mature innovations like DiracX, token-native Rucio, and HPC integration, areas where larger WLCG experiments have limited capacity to transition and benchmark now.

        Speaker: Giovanni Guerrieri (CERN)
        FCC-distr-computing-10-06-26-12.pdf
      • 8:48 AM
        MC Production Tools and Schedule 18m

        The FCC Physics, Experiments and Detectors program relies on a coherent centralized productions infrastructure to provide datasets for physics analyses, detector performance studies, or other uses during the Reference Design Phase. This talk will present the current status, priorities, and schedule of the FCC MC production and GRID tools activity. It will cover the organization of central productions across the GEN-SIM-DIGI-RECO chain, the use of validated generator configurations, GRID submission workflows, metadata management, and web-based tools for dataset discovery and production requests. Particular emphasis will be placed on the immediate production priorities, including Delphes-based fast simulation studies, extension of the production capabilities to cover CLD full simulation datasets, as well as on the evolution of the production workflow from the current DIRAC-based setup toward future tools. The contribution will also discuss documentation, user support, and coordination mechanisms needed to enable reliable central and private productions for the FCC community.

        Speaker: Pantelis Kontaxakis (Universite de Geneve (CH))
        MCProductionToolsAndSchedule_PK.pdf
      • 9:06 AM
        Key4hep Status and Plans 18m
        Speaker: Juan Miguel Carceller (CERN)
        20260610-carceller-key4hep.pdf
      • 9:24 AM
        ACTS and FCC 18m

        ACTS (A Common Tracking Software) is an experiment-agnostic, open-source track reconstruction toolkit, originally derived from the ATLAS Inner Detector reconstruction software. It provides a comprehensive set of tracking algorithms covering geometry description, track finding, and track fitting, and has been extended over time to be fully independent of any specific experiment.

        With recent developments in the ACTS library and the key4hep environment, first ACTS-based tracking workflows are now available for FCC detector concepts. A baseline geometry description is in place, and remains an area of active development.

        This contribution reports on these developments, gives an overview of what is currently available, and outlines planned future work.

        Speaker: Paul Gessinger (CERN)
        2026-06-10_acts-fcc-week_v5.pdf
      • 9:42 AM
        Leveraging Synergies Between CEPCSW and FCCSW 18m

        The Circular Electron-Positron Collider (CEPC) needs a strong and flexible software system to support detector design, simulation, reconstruction, and physics analysis. The CEPC software (CEPCSW) is part of the Key4hep ecosystem and uses well-established tools: the Gaudi framework for event processing, EDM4hep for data modeling, DD4hep for detector description, Geant4 for simulation, and ROOT for analysis.

        Custom software has been developed to meet the needs of different detector technologies. Algorithms are in place for silicon trackers, time projection chambers, crystal-bar electromagnetic calorimeters, scintillator-glass hadronic calorimeters, muon detectors, and alternatives such as drift chambers and Si-W ECALs. Particle identification uses ionization measurements (dN/dx and dE/dx from gaseous detectors) together with time-of-flight measurements. A new particle flow algorithm, CyberPFA, follows the particle flow principle while solving challenges of the long crystal-bar ECAL design. For visualization, two event display platforms are being developed: one based on Phoenix and the other on Unity.

        Looking ahead, significant synergies are expected between CEPCSW and FCCSW, enabled by their shared foundation within the Key4hep ecosystem. Future collaboration may include the co-development of detector-agnostic algorithms such as tracking, dN/dx measurement, and particle flow (PFA), along with a unified strategy for continuous integration and an automated performance validation framework to ensure cross-experiment code correctness and long-term stability. Beyond these core areas, joint efforts may extend to a shared analysis layer built on EDM4hep, a unified abstraction layer for heterogeneous computing, and applications of artificial intelligence. Collectively, these synergies will foster a sustainable, efficient, and collaborative software ecosystem that strengthens both communities and supports their long-term scientific goals.

        Speaker: Prof. Sheng-Sen Sun (Institute of High Energy Physics, Chinese Academy of Sciences)
        20260610 FCCWeek sunss.pdf
    • 8:30 AM → 10:00 AM
      Technical Infrastructure: RF Points and Cryogenics F3005

      F3005
      • 8:30 AM
        FCC-ee cryogenic studies status in the Reference Design Report (RDR) phase 30m

        The design maturity of the Future Circular Collider (FCC-ee) cryogenic system has progressed significantly from its initial concept in 2014 reaching its feasibility report in 2025. With 3 major reports published in between, being the Conceptual Design Report (CDR) in 2018, the Mid-Term Review Report (MTR) in 2023 and the Feasibility Study Report (FSR) in 2025, the FCC Study is now entering its final chapter (Reference Design Report – RDR – phase) as a pivotal milestone towards a targeted project approval in 2028. For cryogenics, the forthcoming RDR is expected to include feedback from industrial partners on the proposed design, targeting to be completed by the end of 2027. The European Strategy Group (ESG) reported in 2025 the FCC-ee as CERN’s next flagship collider project. This talk will put the cryogenic system design of FCC-ee into this perspective, while summarizing its main outcomes and findings. It will bring a strategic view on the expectations of the RDR, including ongoing parallel studies, and proposed R&D developments for the post-RDR phase.

        Speaker: Laurent Delprat (CERN)
        2026_FCC-Week_Cryo-studies-status_Delprat.pdf
        2026_FCC-Week_Cryo-studies-status_Delprat.pptx
      • 9:00 AM
        FCC-ee cryogenics: Baseline updates and parallel studies 30m

        The current baseline foresees cryogenic cooling at Points H and L for the RF collider and booster systems. Included in the presentation are the latest updates to the cryogenic architecture, heat-load estimates, installed cooling capacity, utility assumptions, and other ongoing parallel studies supporting the cryogenic system design. Together, these activities aim to strengthen the FCC-ee cryogenic baseline and prepare for the design stages for the reference design phase, R&D and beyond.

        Speaker: Anita Petrovic
        2026-06-10_FCC_Cryogenics_Baseline_updates_and_parallel_studies_AP.pdf
        2026-06-10_FCC_Cryogenics_Baseline_updates_and_parallel_studies_AP.pptx
      • 9:30 AM
        Industrial validation of FCC-ee cryogenics proposal: status update 30m
        Speaker: Thomas Luc Swerts (CERN)
        20260610_TLSwerts_FCC-eeCryogenics_Industrial_Engineering_Studies_StatusUpdate.pdf
        20260610_TLSwerts_FCC-eeCryogenics_Industrial_Engineering_Studies_StatusUpdate.pptx
    • 10:00 AM → 10:30 AM
      Coffee break 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 10:30 AM → 12:00 PM
      Accelerator Technical Design: Powering F3017

      F3017
      Convener: Jean-Paul Burnet (CERN)
      • 10:30 AM
        Magnet’s powering circuit layout update 25m

        This talk shows the latest updates in the magnet powering layout for the FCC-ee, following the LCC optics lattice. An update in the powering strategy and number of power converter is provided.

        Additionally, this presentation summarizes a Life Cycle Assessment of a quadrupole trimming magnet powering circuit for FCC applications, evaluating environmental impacts across all life cycle stages. The results identify key environmental hotspots to support more sustainable and ecodesign-oriented development of FCC powering systems.

        Speaker: Nagore Pinillos Zamorano (CERN)
        FCC_Week2026_MagnetPoweringCircuitLayoutUpdate_N_Pinillos.pdf
        FCC_Week2026_MagnetPoweringCircuitLayoutUpdate_N_Pinillos.pptx
      • 10:55 AM
        System-Level Optimization: Transition to LCC 25m

        This work presents a system-level framework for the joint CAPEX and OPEX optimization of coupled accelerator subsystems, with environmental impact considered in parallel. The framework integrates models of magnets, power converters, DC cables, civil engineering, electrical equipment, and cooling and ventilation. Results from a comparison of the GHC and LCC optics show that the LCC achieves substantially lower total expenditure, though its baseline was not thoroughly optimized at that stage. The present work addresses this gap, transitioning to a full optimization of the LCC baseline, with sensitivity analysis employed to prioritise model refinements and initial results presented.

        Speaker: Andela Rankovic
        FCC_Week_System_Optimization_AR.pdf
        FCC_Week_System_Optimization_AR.pptx
      • 11:20 AM
        Powering RF for FCC-ee 20m

        This presentation addresses the electrical powering of RF amplifiers, specifically tristrons and solid-state amplifiers, for both the FCC-ee collider and booster.
        The baseline solution is a centralized system delivering 130 MW through a high-power converter.
        This has been established with an optimization module using Genetic algorithm.
        Few of the challenges for this powering scheme is presented – RPO and replacement of the crowbar protection system. Description of a testbed being prepared is presented. The testbed aims to de-risk the filtering stage to address the RPO induced ripple component, the series disconnect switch and verify that the disconnect module works under RPO. The testbed would also be utilized to validate the tristrons once they are ready. Finally, stability of the DC distribution bus is addressed.

        Speaker: Dr Jayakrishnan Harikumaran (CERN)
        FCC_Week_RF_Powering.pdf
        FCC_Week_RF_Powering.pptx
      • 11:40 AM
        The HTS4 and CPES projects of CHART: the use of HTS conductors in FCC 20m

        The HTS4 project, now in its final year, is developing a nested high-temperature superconducting quadrupole-sextupole magnet system for the FCC-hh arcs. This compact, combined-function design targets significant reductions in electrical consumption compared to conventional arc magnet schemes. We present the current status of the project, including design progress, prototype development, and key results to date. In parallel, the sister project CPES has demonstrated the use of cryogenic power supplies to drive these HTS magnets, an essential enabling technology for an efficient powering scheme. Together, HTS4 and CPES contribute to reducing the energy footprint and operational cost of the FCC arcs, supporting the sustainability goals of the next-generation collider.

        Speaker: Francesco Bardi
        HTS4_CPES_FCCWeek2026.pdf
        HTS4_CPES_FCCWeek2026.pptx
    • 10:30 AM → 12:00 PM
      FCC-ee Injector: FCC-ee Injector Overview and Damping Ring F3003

      F3003
      Convener: Paolo Craievich
      • 10:30 AM
        Technical Coordination Experiences at PSI from SwissFEL and SLS 2.0 for the FCC-ee Injector 25m
        Speaker: Johan Wickström
        PSI_SwissFEL_SLS_Installations_20260610_v2.pdf
        PSI_SwissFEL_SLS_Installations_20260610_v2.pptx
      • 10:55 AM
        Civil Engineering for the FCC Injector Complex 20m

        This presentation shall provide an outline of the current conceptual layout of the FCC Injector Complex and key civil engineering factors that will influence the decision on final placement of the facility. Some of the placement options considered to date will be presented. Geotechnical and groundwater considerations will be presented along with a brief explanation of the work to be done and the key input data necessary to be able to commence the detailed design in Q4 2028.

        Speaker: Timothy Paul Watson (CERN)
        260608_FCC_Week_CE_Injector_Complex.pdf
        260608_FCC_Week_CE_Injector_Complex.pptx
      • 11:15 AM
        Status of the DR at 2.86 GeV 25m

        The FCC-ee collider requires excellent lepton beam quality from the injector complex for both bootstrap and top-up operations. Given the high charge requirements, and the operational needs of the intermediate acceleration stage in the booster ring, the injector complex must deliver alternating particle trains with opposite charges.
        During the Feasibility Study, various design options and energy levels were evaluated before establishing the current baseline configuration.
        The injector layout includes now separate LINACs that accelerate electrons and positrons up to an energy of 2.86 GeV. Both species are then injected into the Damping Ring to reduce emittance and energy spread, prior to being accelerated to 20 GeV via a dedicated LINAC. The Damping Ring is essential to achieve the required emittance within a damping time that ensures optimal injection efficiency for the Main Rings.
        This contribution reviews some key aspects of the new High-Energy damping ring for electrons and positrons, providing a comprehensive status report on its current design.

        Speaker: Catia Milardi (INFN e Laboratori Nazionali di Frascati (IT))
        20260609_FCC_Week_Injector_DR_CM.pdf
      • 11:40 AM
        Evaluation of FCC-ee damping ring impedance and related instabilities 20m

        The design of the FCC-ee damping ring is progressing, with ongoing optimisation of beam parameters and key accelerator systems.
        Accordingly, the coupling impedance model is updated to reflect the latest vacuum chamber and hardware layouts.
        In parallel, the estimates of collective effects and impedance-related instabilities are being refined.
        This talk presents the current wakefield and impedance models for the
        FCC-ee damping ring and reports the results of the respective instability studies, including possible mitigation strategies.

        Speaker: Shalva Bilanishvili
        2026_06_10_FCCDR_CE_Bilanishvili.pptx
    • 10:30 AM → 12:00 PM
      Physics, Experiments and Detectors: Detectors (ii) F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Convener: Valentina Cairo (CERN)
      • 10:30 AM
        Highly granular calorimeters with fully embedded electronics 20m

        Concepts for highly granular calorimeters with fully embedded electronics have been developed in different technologies within the CALICE and FCAL collaborations with the aim of optimally exploiting the Particle Flow Algorithm for jet reconstruction. Within the DRDCalo collaboration large-scale prototypes allowing to demonstrate also the construction and integration aspects are being built and tested stand-alone and in different combinations of an electromagnetic and a hadronic section. The main categories of technologies being considered in these sandwich calorimeters are: highly pixelised electromagnetic calorimeters, hadronic calorimeters with optical tiles and hadronic calorimeters with gaseous active layers.

        Speaker: Lucia Masetti (Johannes Gutenberg Universitaet Mainz (DE))
        DRDCalo_WP1_Masetti.pdf
      • 10:50 AM
        ALLEGRO Noble Liquid Calorimeter 14m

        The ALLEGRO ECAL group is developing a noble liquid electromagnetic calorimeter designed to deliver high granularity, low-noise operation, and excellent energy resolution, meeting the demanding requirements of precision physics measurements at the FCC-ee. Current end-to-end R&D activities span detector-level design, electrode and cold front-end electronics development, simulation and software tools for performance characterization and optimization, and prototype validation through laboratory measurements. Recent progress and future plans will be presented.

        Speaker: Dr Mikael Mieskolainen (CERN)
        NLC_FCC_Mieskolainen_100626.pdf
      • 11:04 AM
        Optical Readout Calorimetry 20m
        Speaker: Hwi Dong Yoo (Yonsei University (KR))
        HDYOO_FCCWeek26_06102026.pdf
      • 11:24 AM
        Muon Systems 18m
        Speaker: Tae Jeong Kim (Hanyang University (KR))
        2026_0610_FCCweek_Muon.pdf
      • 11:42 AM
        CEPC detector R&D 18m
        Speaker: Joao Guimaraes da Costa (IHEP)
        20260610-AGORA-CEPC-FCC-Week-Helsinki.pdf
    • 10:30 AM → 12:00 PM
      Physics, Experiments and Detectors: Physics Studies (ii) F2044 Auditorium

      F2044 Auditorium
      Convener: Eric Laenen (Nikhef National institute for subatomic physics (NL))
      • 10:30 AM
        Four-jet production at electron-positron colliders at NNLO 18m

        In this talk I will present the calculation of the next-to-next-to-leading order (NNLO) correction to four-jet production at electron-positron colliders. I will highlight the details of the calculation, which is performed with the antenna subtraction technique, present precise phenomenological predictions for the four-jet rate and discuss the agreement with LEP data.

        Speaker: Matteo Marcoli (University of Durham)
        Marcoli_FCC_Week_2026.pdf
      • 10:48 AM
        Cornering Natural SUSY at a Tera-$Z$ Factory 18m

        We discuss indirect probes of the MSSM at FCC-ee, with particular emphasis on the complementarity between single Higgs production and electroweak precision tests at the Tera-$Z$ run. In addition to flavor-universal contributions to the $STWY$ oblique parameters, we point out important flavor non-universal effects. An example of the latter is the heavy Higgs doublet, which gives tree-level shifts in Higgs couplings as well as sizeable RGE contributions to the $Zbb$ vertex. Overall, we find that FCC-ee can probe the MSSM in the multi-TeV range, and test the naturalness of the EW scale at the per-mille level.

        Speaker: Alessandro Valenti (University of Basel)
        slides_AV.pdf
      • 11:06 AM
        Long-lived Left-Right Symmetry at FCC-ee 18m

        We give an extensive discussion of the displaced signals of heavy Majorana neutrino production at future electron-positron colliders operating at various proposed energies in the context of the Left-Right symmetric model. A comprehensive collection of channels is taken into account, ranging from those featuring $W$ and $W_R$ mediation to those induced by scalar mixing and gauge/scalar boson fusion, with connections to the mechanism of neutrino mass origin. The emerging signatures feature possibly multiple displaced heavy neutrinos that are in some cases accompanied by prompt activity and forward leptons. We derive the corresponding total production rates and differential distributions, which allow us to differentiate the channels and have analytical estimates of the signal yield. We then develop realistic estimates of the selection efficiencies using a dedicated vertexing algorithm which establishes the displaced decay positions and supplies a reliable proxy for reconstructing the full four-momenta of long-lived particles. This allows to determine the realistic reaches in the parameter space of the Left-Right symmetric model across the various channels, and we show that these can strongly surpass the LHC ones, demonstrating that future lepton colliders are sensitive to left-right symmetry breaking scales in the deep multi-TeV regime.

        Speaker: Jonathan Kriewald (Jožef Stefan Institut)
        JK_FCCWeek_2026.pdf
      • 11:42 AM
        Warm dark matter at the FCC 18m
        Speaker: Duarte Da Silva Feiteira
        presentation_FCC_duarte.pdf
    • 10:30 AM → 12:00 PM
      Technical Infrastructure: Cooling & Ventilation F3005

      F3005
      • 10:30 AM
        FCC Ventilation Design Updates 30m

        This presentation will focus on the ventilation design decisions taken since the Feasibility Study: specifically, on how the accelerator tunnel is ventilated, both in normal operation and in an emergency, and how the air of the accelerator tunnel is kept within the required temperature range. The results of the Pugh Matrix assessments for the decisions, highlighting safety and environmental improvements will be discussed. The progress made on the new baseline design will be shown as well as the latest results of supporting calculation models. This presentation will also cover the latest user requirements, with the corresponding impact on equipment sizing and integration of the ventilation equipment.

        Speaker: Andrew Coleman (CERN)
        Ventilation_FCCWeek_2026 final.pdf
        Ventilation_FCCWeek_2026 final.pptx
      • 11:00 AM
        FCC Cooling Infrastructure 30m

        This contribution presents the ongoing development of the FCC cooling infrastructure architecture within the FCC Reference Design activities.

        The presentation will provide an update on the evolution of user cooling requirements and thermal loads, including the recent transition from GHC to LCC beam optics and the expected future evolution of loads currently under development within the FCC study teams.

        The review of the cooling distribution architecture will also be discussed, including the assessment of alternative network configurations for primary water, chilled water, and demineralised water systems.

        Speaker: Daniel Najdrowski (CERN)
        EN CV - FCC Cooling Architecture.pdf
        EN CV - FCC Cooling Architecture.pptx
      • 11:30 AM
        Cooling tower and water services management for FCC 30m

        In the present contribution, an update on the cooling towers and water services management for FCC is thoroughly discussed. Cooling towers conform the main heat rejection mechanism from FCC to the environment. The raw water network supplies make-up to compensate for evaporation losses in the cooling towers, among others. To reduce the make-up water consumption, recycling of the cooling tower blowdown is foreseen, as well as the management and treatment of the blowdown recycling effluent. Production of demineralised water is also required for the initial fill of the demineralised water circuits and to refill them in case of accidental leaks or deliberate emptying. Sumps pump infiltration water from the FCC underground areas up to the surface. Other networks include the drinking water for sanitary uses and firefighting water.

        Speaker: Inigo Martin Melero (CERN)
        Towers&Networks_IMM_v6.pdf
    • 12:00 PM → 1:30 PM
      Lunch break 1h 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 1:30 PM → 3:00 PM
      FCC-ee Accelerator: Operation and Performance F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: John Theodore Seeman (SLAC National Accelerator Laboratory)
      • 1:30 PM
        Electron Cloud: Filling Scheme Constraints and Collective Effects 20m
        Speaker: Lotta Mether (CERN)
        FCC_Week_2026_ecloud_collective.pdf
        FCC_Week_2026_ecloud_collective.pptx
      • 1:50 PM
        Design of the collimation system and its efficiency in the IRs 25m

        The Future Circular electron-positron Collider (FCC-ee) is designed to explore physics beyond the present energy and luminosity frontiers for leptons. To achieve its physics goals, the FCC-ee must store and collide very high-intensity lepton beams, with stored beam energies of up to 17.8 MJ — posing unique collimation challenges. A robust and reliable beam collimation system is therefore indispensable, both to protect sensitive machine components from beam loss damage and to minimize backgrounds in the experimental detectors.
        This contribution presents the current status of collimation studies for the FCC-ee baseline optics (LCC V106.2), covering the design and performance evaluation of the collimation system under selected beam loss scenarios. The efficiency of the collimation system in suppressing losses in the Interaction Regions (IRs) — a critical figure of merit for detector background mitigation — is assessed in detail.

        Speaker: Giacomo Broggi (CERN)
        FCCweek2026_GB.pdf
        FCCweek2026_GB.pptx
      • 2:15 PM
        Top-up Injection challenges 15m
        Speaker: Yann Dutheil (CERN)
        top-up-injection.pdf
        top-up-injection.pptx
      • 2:30 PM
        Optics measurements in the FCC-ee 15m
        Speaker: Jacqueline Keintzel (CERN)
        20260610_Keintzel_FCCWeek_FCCOpticsMeasurements.odp
        20260610_Keintzel_FCCWeek_FCCOpticsMeasurements.pdf
      • 2:45 PM
        Dynamic effects in the Collider: Global orbit feedback and power supply ripple 15m

        FCC-ee performance relies on ultra-low vertical emittances, making the machine highly sensitive to time-dependent perturbations. This work presents first beam dynamics studies of the impact of ground motion and power supply ripple. For ground motion, a global orbit feedback model based on LHC experience is used to evaluate correction efficiency and derive first bandwidth requirements. The studies show that FCC-ee is extremely sensitive to ground motion, with nanometre-scale perturbations potentially leading to significant vertical emittance growth. A robust and reliable global orbit feedback system will therefore be critical for FCC-ee operation. For power-supply ripple, dipole and quadrupole field modulations are studied to estimate first ripple tolerances. The response is strongly frequency dependent, showing that specifications must limit ripple amplitude while also avoiding sensitive frequency bands.

        Speaker: Sofia Kostoglou (CERN)
        FCCee_ColliderDynamicEffects.pdf
        FCCee_ColliderDynamicEffects.pptx
    • 1:30 PM → 3:00 PM
      Physics, Experiments and Detectors: Joint session Physics & Physics Software and Computing F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Convener: Michele Selvaggi (CERN)
      • 1:30 PM
        MC Generators Status and Plans 18m
        Speaker: Andrzej Konrad Siodmok
        FCC Helsinki 10.06.26.pdf
      • 1:48 PM
        Analysis Tools and Visualisation 18m
        Speaker: Juraj Smiesko (CERN)
        analysis-and-visualisation-tools-fcc-week-2026.pdf
        Analysis and Visualization Tools
      • 2:06 PM
        Tracking and Vertexing Status and Plans 18m
        Speaker: Andrea De Vita (CERN & Università di Padova)
        1006026_FCCWeek2026_DeVita-3.pdf
      • 2:24 PM
        High Level Reconstruction Status and Plans 18m

        This talk reviews the current status and plans for the reconstruction, covering particle-flow performance and object-level reconstruction (leptons, photons, jets) across various detector concepts of FCC-ee. We will also review the status of high-level reconstruction, such as jet flavor tagging and tau reconstruction, where modern machine-learning-based approaches are driving substantial gains.

        Speaker: Sanghyun Ko (CERN)
        260610_FCCweek_shKo.pdf
      • 2:42 PM
        LEP Data Status and Plans 18m
        Speaker: Apranik Fatehi (University of Hamburg - CERN - DESY)
        LEP-Data-Status-Plans.pdf
    • 3:00 PM → 3:30 PM
      Coffee break 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 4:00 PM → 5:30 PM
      Nordic–Baltic Engagement in Large-Scale Research Projects F2044 Auditorium

      F2044 Auditorium
      Conveners: Henning Kirschenmann (LUT University and Helsinki Institute of Physics (FI)), Kenneth Oesterberg (Helsinki Institute of Physics (FI))
    • 6:30 PM → 10:30 PM
      Conference dinner 4h Finlandia Hall

      Finlandia Hall
  • Thu, June 11
    • 8:30 AM → 10:00 AM
      Accelerator Technical Design: Machine protection & Availability F3017

      F3017
      Convener: Jan Uythoven (CERN)
      • 8:30 AM
        Buying Physics: Performance–Cost Design Trade-offs for Availability and Integrated Luminosity 22m
        Speaker: Jack Heron (CERN)
        slides.pdf
        slides.pptx
      • 8:52 AM
        Designing for maintainability in the FCC era 22m
        Speaker: Mrs Johanna Mattiasson
        Designing for Maintainability in the FCC era_FCC Week 2026_Johanna Mattiasson_06.11.pdf
        Designing for Maintainability in the FCC era_FCC Week 2026_Johanna Mattiasson_06.11.pptx
      • 9:14 AM
        Recent results of powering failure studies for FCC-ee 22m

        The FCC-ee will store 17.5 MJ per beam at Z-pole operation, with extremely high energy densities arising from the very small beam emittances. Powering failures are among the fast failure modes that set stringent requirements on the machine protection system, and their characterisation is essential for defining interlocking and detection strategies.
        This presentation reports on powering failure studies in the Local Chromaticity Correction (LCC) lattice. For main dipole circuits, the powering by arc including the dispersion suppressors is shown to produce significantly slower horizontal orbit excursion growth compared to earlier lattice configurations (powering by half-arc). The physics mechanisms driving this behaviour are discussed. Results for quadrupole powering failures are also presented, including the effect of the dipole tapering on the beam response. The status of the tapering study and its implications for failure simulations are outlined. Mitigation measures and requirements for the machine protection system are derived from these results.

        Speaker: Delphine Domange (Universite Libre de Bruxelles (BE))
        FCCWeek2026_PoweringFailureStudies.pdf
        FCCWeek2026_PoweringFailureStudies.pptx
      • 9:36 AM
        Studies of beam-dust interactions 22m

        Interactions between macroscopic dust grains and circulating particle beams have been observed in a wide range of accelerators and have the potential to significantly limit the performance of FCC. This presentation discusses the three main phases of beam-dust interaction: dust release from the surface, dust motion and dynamics, and potential disintegration of the dust grain by impacting beam particles. Results from beam studies, laboratory experiments, and dust-dynamics simulations are reported, and their consequences for the design of the vacuum and machine protection system are discussed. While the presentation focuses on FCC-ee, the relevance of beam-dust interactions for FCC-hh is also assessed.

        Speaker: Ingrid Midtbust Hjelle (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        FCC_week_2026_beam_dust_studies.pptx
    • 8:30 AM → 10:00 AM
      FCC-ee Injector: Injector F3020

      F3020
      Convener: Caterina Vernieri (SLAC National Accelerator Laboratory (US))
      • 8:30 AM
        Electron source(s) studies 20m

        The FCC-ee electron source must deliver up to 5 nC in four bunches at 200 Hz with shot-to-shot charge variation for top-up injection. The baseline RF photogun design has been studied in ASTRA simulations, demonstrating compliance with following pre-injector complex. A charge variation scheme, based on modulating the transverse emission radius to maintain constant charge density, is proposed to preserve emittance across the full charge range. A dedicated test stand currently under commissioning at PSI will experimentally validate this design, including pulse-to-pulse charge modulation and cathode lifetime under high-charge conditions. The recent addition of an electron damping ring to the FCC-ee layout has relaxed the emittance budget, opening the door to a simpler thermionic gun alternative; first design studies and a preliminary comparison with the photoemission baseline are presented.

        Speaker: Zdenek Vostrel (CERN / EPFL)
        Electron sources studies - FCC week 2026.pdf
        Electron sources studies - FCC week 2026.pptx
      • 8:50 AM
        Positron production and linac, P3 status 20m

        The high-luminosity FCC-ee collider will require a low-emittance positron beam with sufficient intensity to ensure efficient top-up injection and short filling times. Since the FCC-ee Feasibility Study Report, design studies of the positron source have continued, with particular focus on the RF frequency and aperture of the capture and positron linacs. The present baseline relies on a conventional positron source, in which a 2.86 GeV electron beam impinges on a 15 mm thick tungsten target. The produced positrons are captured using an HTS solenoid-based matching device, followed by a 3 GHz capture linac embedded in a 0.5 T DC solenoidal magnetic field, which accelerates the beam to ~170 MeV. Downstream of the capture section, quadrupole focusing is used to transport the beam up to the 2.86 GeV damping ring. The positron linac is based on 3 GHz accelerating structures and is divided into two sections with different focusing parameters adapted to the increasing beam rigidity. This contribution will present the current status of the FCC-ee positron source design including the positron linac layout and recent optimization studies. In this context, a dedicated experiment is foreseen at the SwissFEL facility at PSI to demonstrate experimentally the full positron production chain relevant for FCC-ee. This project is called P³ (PSI Positron Production experiment) and will be hosted in one of the future SwissFEL beamlines. The design and construction are now completed, with first operation expected in summer 2026. An update on the status and preparation of the P³ experiment will also be presented.

        Speaker: Dr Iryna Chaikovska (CNRS/IJCLab)
        positrons_FCCweek2026_Chaikovska.pdf
        positrons_FCCweek2026_Chaikovska.pptx
      • 9:10 AM
        Optimisation of the positron linac at 3 GHz 15m

        A high-performance positron source is essential for FCC-ee to provide the high-intensity, low-emittance beams required for rapid injection, especially in the Z-pole operation mode. In the FCC-ee Feasibility Study, the reference positron source is based on a 2.86 GeV electron drive beam impinging on a 15 mm tungsten target, followed by an HTS matching device and a 2 GHz travelling-wave RF capture section embedded in a 0.5 T solenoidal channel. A chicane is used to separate electrons from positrons, after which the positron linac is divided into two sections: a solenoid-focused section with 0.5 T normal-conducting solenoids around the RF structures, followed by a FODO-based section with quadrupole focusing between RF structures.

        This work investigates 3 GHz S-band RF structures as potential alternatives for the FCC-ee positron linac, motivated by the maturity and wide availability of S-band high-power RF technology. Travelling-wave, standing-wave, and hybrid SW/TW capture-linac layouts are studied and compared with the 2 GHz Feasibility Study reference using an RF-Track–Xopt simulation and optimization workflow. In addition, a downstream option after the separator chicane is considered, where 3 GHz TW accelerating structures are combined with quadrupole-based focusing. The comparison is based on the positron yield in the main RF bucket and the resulting beam phase-space properties. Preliminary results indicate that the 2 GHz Feasibility Study reference remains superior in terms of main-bucket yield, while the configuration combining a 3 GHz TW capture linac with a downstream section based on 3 GHz TW accelerating structures and quadrupole focusing provides a favorable compromise between yield and beam quality. An Octree-based 6D beam-core analysis is further used to complement the yield comparison and assess the 3 GHz capture and downstream-optics options.

        Speaker: Mr Yuting WANG (CNRS/IJCLab)
        FCCweek_PositronSource_202606_Yuting WANG.pdf
        FCCweek_PositronSource_202606_Yuting WANG.pptx
      • 9:25 AM
        HE Linacs: status, highlights and outlook 20m

        The FCC-ee injector complex is designed to deliver tunable, high-charge electron and positron bunches for injection into the collider over a centre-of-mass energy range of 90–365 GeV. A key component is the high-energy (HE) linac, which accelerates the beam from approximately 3 to 20 GeV prior to injection into the booster.
        The present design has been established through comprehensive beam-dynamics studies aimed at minimizing emittance growth and optimizing transverse beam stability along the HE linac. The linac is segmented into three main sections—bunch compressor, main linac, and energy compressor. This contribution provides a detailed overview of the layout and component requirements of each section, with the objective of informing and guiding the engineering design.
        While the selected configuration satisfies current performance requirements for efficient booster injection and supports the operational goals of the FCC-ee injector complex, several potential improvements are discussed. In particular, options to shorten the HE linac are considered, leveraging possible synergies with upstream and downstream systems.

        Speaker: Simona Bettoni
        Bettoni_FFCCWeek2026.pdf
        Bettoni_FFCCWeek2026.pptx
      • 9:45 AM
        Multi-bunch effects in the HE linac 15m
        Speaker: Andrea Latina (CERN)
        FCC_week_presentation_Latina.pptx
    • 8:30 AM → 10:00 AM
      FCC-hh Accelerator: FCC-hh & High-field magnets (i) F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Gianluigi Arduini (CERN)
      • 8:30 AM
        Advances in lattice designs for the FCC-hh 20m

        We show a newly optimised lattice for the FCC-hh, which, enhancing the FSR baseline, is capable to reach a beam energy of 44.1 TeV using 16 m dipoles. The new lattice, with fully matched optics, is presented along sensitivity studies to see what is the attainable energy depending on other parameters such as injection energy. Furthermore, the possibility of an alternative lattice based on combined-function magnets is discussed.

        Speaker: Federico Capoani (CERN)
        FCChh_Capoani_20260611.pdf
      • 8:50 AM
        The HFM program 20m

        In this talk we will give the status of the High Field Magnets programme, focussed on the development of the main dipoles for the FCC-hh. After reviewing the baseline and the options, we will outline the main development lines both in LTS and HTS, and present the recent results and challenges.

        Speaker: Dr Ezio Todesco (CERN)
        slides
      • 9:10 AM
        Advances in High Field HTS Accelerator Magnet Technology at IHEP-CAS 20m

        The Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences is pursuing the advanced high field HTS superconducting magnet technology for the next-generation particle accelerators. Significant progresses have been achieved in the past years: world’s first achievement of 14 T dipole field in the aperture with ReBCO insert coils at 4.2 K; the IBS model solenoids reached 49 A stable operating current at 35 T background field; the transposed IBS cable reached a quench current of 7100 A, and the quench propagation speed of the IBS conductor has also been experimentally measured, showing its superiority over traditional HTS conductors: easy to protect during quench, better mechanical properties. The talk will present the latest promising progress and discuss the possible solutions for the issues to be solved in the next years.

        Speaker: Qingjin Xu
        HF Magnet Program-Jun 2026.pdf
        HF Magnet Program-Jun 2026.pptx
    • 8:30 AM → 10:00 AM
      Physics, Experiments and Detectors: Physics Studies 3 F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Conveners: Gaelle Boudoul (Centre National de la Recherche Scientifique (FR)), Santeri Laurila (CERN & Helsinki Institute of Physics (FI))
    • 8:30 AM → 10:00 AM
      Technical Infrastructure: Safety F3005

      F3005
      • 8:30 AM
        Update of the safety concept and roadmap towards a Reference Design 18m

        A first version of the Safety Concept for the Future Circular Collider (FCC) was presented in the Feasibility Study report. It underwent peer review by both internal and external expert committees, which confirmed the absence of showstoppers at this stage while identifying a comprehensive set of aspects requiring further development.
        The current objective is to build on the foundation set a year ago by refining the concept and optimising the associated safety solutions, with the aim of reducing uncertainties and addressing the points raised during the review process.
        A detailed roadmap has been developed to establish a Reference Design by the end of 2027 for the Safety Concept, comprising 42 activities structured into 9 main tasks and 19 deliverables.
        This presentation will highlight the key milestones identified in the roadmap, outlining the planned progression towards the Reference Design. It will also present a selection of safety studies carried out since the last FCC Week, illustrating the main changes in the concept and how they will be managed and implemented moving forward.

        Speaker: Andre Henriques (CERN)
        FCC_week_2026_safety_concept_AH.pdf
        FCC_week_2026_safety_concept_AH.pptx
      • 8:48 AM
        Compartment and evacuation strategy: towards integration, optimization and inclusion of human factors 18m

        The Future Circular Collider (FCC) proposes an unprecedented evacuation concept for long underground tunnels, relying on autonomous vehicles to support emergency egress over distances of several kilometres. In the event of a fire, smoke will be contained through a combination of static and dynamic confinement through fire compartments and an air-management system operating in emergency mode.

        Work carried out following the publication of the feasibility study has focused on better aligning the safety strategy with the requirements of other disciplines and with standard tunnel operations. These include transportation, ventilation, maintenance, and, critically, human behaviour as a key factor in safety design optimisation.

        The fire compartmentalisation strategy has been revised based on the outcomes of brainstorming sessions involving multiple CERN departments. A new configuration has been proposed and evaluated alongside modifications to the ventilation concept.

        In parallel, the influence of personality traits and psychosocial factors on human behaviour during autonomous-vehicle-assisted evacuation scenarios has been investigated. An experimental campaign has been initiated to collect empirical data in support of an evidence-based design.

        The outcomes of this research are expected to provide valuable empirical data on human behaviour in emergency evacuations involving autonomous technologies, particularly in underground infrastructures. The results will support the refinement of FCC evacuation strategies, contribute to the assessment of human-related risks and Required Safe Egress Time (RSET), and facilitate the systematic integration of human factors into the design of autonomous evacuation systems.

        Speaker: Ada Malagnino (CERN)
        20260611_FCC_week_2026_compartments_evacuation_AM_rv.pdf
        20260611_FCC_week_2026_compartments_evacuation_AM_rv.pptx
      • 9:06 AM
        Numerical simulations on fire and helium spill scenarios for the safety of the FCC design 18m

        Fire safety and cryogenic hazards are critical considerations in the design of the Future Circular Collider (FCC), where its underground nature and high-energy systems introduce multiple risks to personnel. This work presents a combined numerical investigation of fire scenarios and accidental helium releases, addressing two key hazards in the FCC design. The simulations support validation of the proposed ventilation concept and fire compartment strategy, with the objective of optimizing the design and contributing to the life safety assessment of the facility.
        For the fire safety analysis, simulations are performed using the Fire Dynamics Simulator (FDS) to evaluate the impact of ventilation, smoke extraction, and compartmentalisation strategies in FCC tunnel arcs. Configurations with compartment lengths of 400 m and 1600 m are assessed, along with lay-by zones in front of alcoves. Heat release rates up to 8 MW are considered to represent credible scenarios, including the effect of a fast intervention response robot. The study examines the evolution of smoke, temperature, and flow fields, as well as the performance and potential failure modes of different design strategies. It provides quantitative support for the compartmentalisation approach and enables comparison of technical solutions in terms of their effectiveness in meeting life safety objectives.
        In parallel, oxygen deficiency hazard (ODH) scenarios resulting from accidental helium releases are investigated using OpenFOAM. The simulations capture the dispersion and stratification of helium–air mixtures and are first validated against a controlled helium release experiment in the Large Hadron Collider (LHC), providing a basis for the analysis of representative FCC tunnel scenarios. Key quantities of interest include oxygen concentration and temperature fields, which govern tenability and evacuation conditions.
        Together, these studies contribute to the ongoing development of the FCC Safety Concept and the consolidation of safety systems into a Reference Design.

        Speaker: Jannes Hopman
        FCCWeekPresentation.pdf
        FCCWeekPresentation.pptx
      • 9:24 AM
        Radiation protection studies for FCC 18m

        Radiation Protection (RP) studies are essential to ensure that the advancing design of FCC-ee systems and infrastructures during the Reference Design phase meets the radiological safety objectives for personnel and for the environment. Radiation transport simulations with the FLUKA Monte Carlo code are carried out to support design optimisation and to anticipate potentially critical radiation protection aspects. Building on the efforts of the Feasibility Study, this contribution provides an overview of the Reference Design milestones for RP, focusing on systems and areas of radiological significance where substantial progress has already been made.

        Updates on the studies for the FCC-ee injector complex are presented, with particular emphasis on the positron production target area. A comprehensive radiation protection study including prompt, residual, and activation considerations has also been performed for the FCC-ee experimental points and for a detector prototype, marking the first such evaluation for FCC-ee. As the design of the beamstrahlung dump system progressed, radiation protection calculations have closely followed its evolution to assess activation levels and their impact on integration, maintenance, and operation. As the integration of accelerator alcoves have significantly advanced, dedicated studies have been performed to study the compliance with radiation protection objectives.

        An outlook is finally provided on the ongoing and upcoming Reference Design activities, including updates of the arc sector studies and refined source-term evaluations for the environmental impact assessment.

        Speaker: Davide Bozzato (CERN)
        FCCWeek2026_SafetyWP_HSE_RP.pdf
        FCCWeek2026_SafetyWP_HSE_RP.pptx
      • 9:42 AM
        FCC Access Control and Safety Systems General Principles 18m

        This presentation focuses on the principles of access control and access safety system’s design for the FCC-ee. Main hazards that the access safety system protects from, and the methodology for reaching the reference design are presented. Possible Elements Important for Safety (EIS), capable of stopping the beams in the FCC are discussed. Principles of sectorising the FCC complex for access control are presented together with their implication on civil engineering and integration, as well as efficient strategies for patrolling the interlocked zones and ensuring traceability of people.

        Speaker: Scott Williams
        FCC Week - Access control and safety systems_General principles.pdf
        FCC Week - Access control and safety systems_General principles.pptx
    • 10:00 AM → 10:30 AM
      Coffee break 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 10:30 AM → 12:00 PM
      Accelerator Technical Design: Beam Intercepting devices F3017

      F3017
      Convener: Anton Lechner (CERN)
      • 10:30 AM
        Beam-matter interaction studies for FCC-ee beam-intercepting devices and SR shielding 25m
        Speaker: Daniele Calzolari (CERN)
        FCCweek2026_calzolari.pdf
        FCCweek2026_calzolari.pptx
      • 10:55 AM
        Mechanical design of FCC-ee collimators 25m
        Speaker: Richard Cowan
        Mechanical Design of Collimators.pdf
        Mechanical Design of Collimators.pptx

        The FCCee collimation presents thermomechanical challenges due to both the small beam size and high intensity. This presentation presents updates for the LCC optics, early studies on beam interactions with collimators, the impact of dedicated shower absorbers, ongoing material development and plans for future work.

      • 11:20 AM
        Design of a liquid lead dump for beamstrahlung radiation absorption 20m

        At the FCC-ee, beamstrahlung radiation generated at the interaction points will produce intense photon beams requiring dedicated absorbers downstream of the collision regions. At Z-pole operation, each photon beam will carry approximately 370 kW of power, creating a challenging thermal load for conventional solid absorbers. A flowing liquid-lead beam dump is therefore under development as a baseline concept, taking advantage of the high density, short radiation length, and thermal robustness of lead.
        This presentation summarizes the evolution of liquid-lead absorber designs for FCC-ee, from initial sloped free-surface concepts to more compact configurations. The design is constrained by the hydraulic limit of the liquid-lead circuit, with a nominal mass flow rate of approximately 300 kg/s, requiring the absorber geometry to maximize the effective photon interaction thickness without increasing the total flow rate. FLUKA Monte Carlo simulations are used to evaluate photon energy deposition and backscattering, while multiphase CFD simulations in ANSYS Fluent assess free-surface dynamics, conjugate heat transfer, and temperature margins.
        Different configurations will be discussed, including single-slope absorbers, double-slope geometries developed to mitigate photon backscattering, and the CUSP concept, Compact Upstream Slope plus Pool. In CUSP, a focused upstream free-surface liquid-lead flow intercepts the peak power density, while a downstream lead pool absorbs the remaining photon power. This design reduces the characteristic absorber length from approximately 5 m to about 1 m while maintaining acceptable thermal margins.
        The presentation will review the main numerical results, design trade-offs, and remaining engineering challenges, including free-surface stability, steel wall, shielding, instrumentation, hydraulic integration, and future prototype development. The results support circulating liquid lead as a feasible and thermally robust technology for beamstrahlung radiation absorption in FCC-ee.

        Speaker: Dr Silvio Candido (CERN)
        FCCweek2026-BS-Candido.pdf
        FCCweek2026-BS-Candido.pptx
      • 11:40 AM
        Design refinements and prototyping of the external shielding for FCCee arc dipoles 20m

        The external shielding for the FCC-ee arc dipoles has been refined ahead of design studies and prototyping with two industrial manufacturers of lead components. Recent thermal simulations evaluated cooling with aluminium cold plates, assessing their suitability for maintaining acceptable lead temperatures and minimising heat load to the FCC tunnel air. This contribution presents the updated design and its predicted thermal performance, details the conclusions from external design studies, and outlines the strategy for prototype procurement, assembly, and testing.

        Speaker: Gabriel Banks (CERN)
        Banks_shielding_design_prototyping_FCCweek.pdf
        Banks_shielding_design_prototyping_FCCweek.pptx
    • 10:30 AM → 12:00 PM
      FCC-ee Injector: Booster overview F3005

      F3005
      Convener: Christoph Montag
      • 10:30 AM
        Booster overview 25m

        We will give an overview of the main features of the FCC-ee high-energy booster This overview will cover the main changes in the booster layout, optics, tuning, and booster operation.

        Speaker: Adnan Ghribi (Centre National de la Recherche Scientifique (FR))
        2026_06_11_heb_overview-3.pdf
        2026_06_11_heb_overview-3.pptx
        HEB review 2026
      • 10:55 AM
        Impedance and collective effects in the High Energy Booster 25m

        A first comprehensive impedance model for the FCC-ee High Energy Booster (HEB) is presented, moving beyond the previously considered resistive wall only description. The updated model incorporates major impedance sources, including RF cavities, bellows, beam position monitors, and tapers, based on a combination of 3D electromagnetic simulations and analytical approaches. This constitutes the first meaningful total impedance budget for the HEB. Using this model, single-bunch stability is investigated with a focus on the transverse mode coupling instability (TMCI) at the 20 GeV injection energy. The results provide an updated assessment of stability margins and identify the dominant impedance contributors driving the instability threshold. These findings represent an important step toward a realistic evaluation of collective effects in the HEB. Extensions of this work to multi-bunch effects are planned for future studies.

        Speaker: Keon Hee Kim (GANIL)
        presentation_CE_booster_FCCweek_2026-1.pdf
      • 11:20 AM
        Optimizing FCC-ee Booster Performance with Damping Wigglers 20m

        The large circumference of the FCC-ee booster makes natural radiation damping very slow at the 20 GeV injection energy, while the demanding Z mode operational scenario simultaneously requires maximum beam charge within a minimal cycle time. This prevents the last injected bunches from meeting collider injection requirements. To address this, the use of damping wigglers is explored, utilizing Multi-Objective Bayesian Optimization (Xopt) to identify the best wiggler configurations that minimize emittance without blowing up the energy spread. These damping wigglers are introduced both at flat bottom and dynamically during the energy ramp, using analytical models alongside Xsuite tracking simulations.

        Speaker: Sudhanshu Thakur (Deutsches Elektronen-Synchrotron (DE))
        Thakur_FCC_WEEK26.pdf
        Thakur_FCC_WEEK26.pptx
      • 11:40 AM
        booster cycle if not covered in overview + filling schemes 20m
        Speaker: Hannes Bartosik (CERN)
        2026.06.11_FCCee_filling-schemes.pdf
        2026.06.11_FCCee_filling-schemes.pptx
    • 10:30 AM → 12:00 PM
      FCC-hh Accelerator: FCC-hh & High-field magnets (ii) F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Attilio Milanese (CERN)
    • 10:30 AM → 12:00 PM
      Physics, Experiments and Detectors: Detectors (iii) F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Convener: Tae Jeong Kim (Hanyang University (KR))
      • 10:30 AM
        ALFA status and plans 18m
        Speaker: Duccio Abbaneo (CERN)
        ALFA_FCCweek_June2026.pdf
        ALFA_FCCweek_June2026.pptx
      • 10:48 AM
        ALLEGRO status and plans 18m
        Speaker: Hucheng Chen (Brookhaven National Laboratory (US))
        ALLEGRO.FCCWeek.20260611.pdf
      • 11:06 AM
        CLD status and plans 18m
        Speaker: Jinlong Zhang (Argonne National Laboratory (US))
        FCCWeek2026_CLD.pdf
      • 11:24 AM
        IDEA status and plans 18m
        Speakers: Paolo Giacomelli (Universita e INFN, Bologna (IT)), Paolo Giacomelli (INFN Sezione di Bologna)
        IDEA detector status and plans-FCC week2026.pdf
      • 11:42 AM
        ILD status and plans 18m

        ILD (International Large Detector) is a long-standing detector concept optimized for the particle flow. While it is originally designed for ILC, it is now also adapted as a FCC-ee detector design.
        I will present the basic concept of ILD, optimization and physics studies in the past, status of detector development as well as recent design and performance studies on adapting circular colliders. I will also present a view to the future of ILD, including focused development topics, new ideas, and action plans as a FCC-ee detector concept.

        Speaker: Taikan Suehara (ICEPP, The University of Tokyo (JP))
        260611-fcceews-ild-suehara.pdf
    • 10:30 AM → 12:00 PM
      Superconducting Radio Frequency: RF System Performance and Beam Stability F3020

      F3020
      • 10:30 AM
        Operational Flexibility and Challenges of the FCC-ee SRF System 18m
        Speaker: Ivan Karpov (CERN)
        FCC_Week_2026_IK.pdf
        FCC_Week_2026_IK.pptx
      • 10:48 AM
        RF optimization of the high-energy booster cycles 18m

        The FCC-ee full-size booster synchrotron prepares electron and positron bunch trains alternately for all foreseen beam energies from 45.6 to 182.5 GeV and operation modes such as filling the collider from scratch or top-up. These require optimizing the energy ramps and RF voltage programs to achieve the small transverse beam sizes for injection in the collider while maintaining longitudinal beam stability. Specifically, the ramp for the Z-pole operating point has an energy overshoot to boost the synchrotron radiation damping effect. The booster RF system consists of 112 superconducting cavities at 800 MHz for the operation modes at Z, WW, and ZH energies, with an additional 408 cavities for the ttbar stage. The first three working points require a wide total voltage range from 50MV to 2 GV. To cover this huge range, Reverse Phase Operation (RPO) will be employed. To provide beam for the relevant operation modes with the booster and provide sufficient voltage per cavity, the RF power requirements are estimated and minimized analytically assuming a defined detuning program. Additionally, transient power requirements of the RF system in the RPO operation are dynamically computed using the BLonD tracking code. Mitigation measures to reduce the power transients are discussed in this contribution.

        Speaker: Lina Valle
        FCC_week_2026_valle.pdf
        FCC_week_2026_valle.pptx
      • 11:06 AM
        Longitudinal HOM damping requirements in HEB 18m
        Speaker: Paula Hickersberger (Vienna University of Technology (AT))
        FCC_Week_Hickersberger.pdf
        FCC_Week_Hickersberger.pptx
      • 11:24 AM
        Studies on the longitudinal beam coupling impedance of the FCC-ee 18m
        Speaker: Hermann Pommerenke (CERN)
        2026-06-11-fcc-week-impedance-studies.odp
        2026-06-11-fcc-week-impedance-studies.pdf
      • 11:42 AM
        Transverse Feedback Strategies for FCC 18m

        This contribution will summarize the transverse feedback strategies for the FCCee. For the feedback kickers, dedicated locations have been identified in the LCC optics for the installation of the kickers. The kicker locations are predominately chosen to be optimally placed for the application as depolarizer kicker in the vertical plane, with all kickers placed at the end of arcs around two opposing IPs. The consequences and limitations of this choice for the use of these kickers as transverse feedback kickers are analyzed with respect to the feedback damping requirements. RF power needs for feedback operation are estimated. The importance of matching dedicated pick-up locations is highlighted.

        Speaker: Wolfgang Hofle (CERN)
        TFB_FCCee_2026.pdf
        TFB_FCCee_2026.pptx
    • 12:00 PM → 1:30 PM
      Lunch break 1h 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 1:30 PM → 3:00 PM
      Accelerator Technical Design: Injection & extraction systems F3017

      F3017
      Convener: Wolfgang Bartmann (CERN)
      • 1:30 PM
        Designing Safe and Efficient Beam Extraction Systems and Dump Transfer Lines for the FCC-ee 20m

        This work presents the design and optimization of the FCC-ee beam extraction system and its associated dump transfer line, with a focus on beam, geometric and machine protection constraints. The extraction system is based on fast kicker magnets and septa, whose number and location are optimized to guarantee efficient beam extraction with minimal uncontrolled losses, to minimize the risks posed by a very high stored beam energy. Special attention is given to failure scenarios such as asynchronous kicker with respect to the abort gap kicker, electric breakdown or loss of one kicker, which can lead to critical damage if not properly mitigated. The transfer line to the beam dump is optimized to control beam size and beam distribution at the dump location, ensuring safe energy deposition and avoiding material damage. Optical functions are carefully tuned to provide sufficient beam dilution, while maintaining robustness against optics and beam errors. A common dump solution shared between the booster and collider is investigated, for each type of beam, introducing additional constraints on optics flexibility, operational modes, and protection strategies. Machine protection considerations are central to the design. A comprehensive protection scheme is proposed, and various failure scenarios are analysed, covering fast failures like kicker malfunction to ensure that the system remains fail-safe under all operating conditions. This study establishes a consistent design approach for FCC-ee beam extraction and dump systems.

        Speaker: Angela Potet
        Beam_dump_transfer_line_Angela_Talk.pdf
      • 1:50 PM
        Kicker Magnets and Generators for the FCC-ee 20m

        Kicker magnets and generators for six distinct beam transfer systems of the FCC-ee are currently under development: the Collider injection and dump systems, the Booster injection, extraction, and dump systems, and the Damping Ring.
        As critical requirement parameters of several of these systems have not yet been fully defined, the current design solutions target preliminary baseline specifications.
        The initial design of a common lumped inductance magnet module is currently being finalised.
        This module is intended to serve as a beamline element for the Booster Extraction, Collider Injection as well as Booster and Collider Dump systems, which share a rise time requirement of 600 ns.
        Laboratory testing and prototyping are foreseen to verify operational parameters, focusing on simultaneously achieving the required rise time, flattop stability, and 304 µs pulse durations, while accommodating long cable runs.
        For systems requiring a fast rise time, specifically the 25 ns for Booster Injection and the 82 ns for the Damping Ring outlined in current draft requirements, a stripline kicker driven by a semiconductor-based inductive adder generator is being investigated.
        Furthermore, alternative concepts, including a nonlinear injection kicker for collider top-up injection, are being evaluated.

        Speaker: Johannes Ruf (CERN)
        FCC-Week-2026_Kicker_Magnets_and_Generators_for_the_FCC-ee.pdf
        FCC-Week-2026_Kicker_Magnets_and_Generators_for_the_FCC-ee.pdf
        FCC-Week-2026_Kicker_Magnets_and_Generators_for_the_FCC-ee.pptx
      • 2:10 PM
        Electro-Magnetic Separator Concept for FCC-ee 20m

        The Future Circular Collider (FCC-ee) requires a dedicated system to separate counter-rotating electron and positron beams in the common RF sections at point PH while preserving beam quality and preventing synchrotron radiation toward the superconducting RF cavities. This contribution presents a novel Electro-Magnetic Separator (EMS) topology that combines an under-vacuum electrostatic device with an external low-field and large-aperture dipole magnet. The proposed concept is designed to ensure precise field alignment along the entire separator length, including fringe-field regions, thereby minimizing unwanted radiation. The system is segmented into multiple units to ensure mechanical feasibility and facilitate fault containment. Key technical challenges remain to be addressed before establishing a viable concept, including high-voltage breakdown under irradiation, beam-coupling impedance, and machine protection under various failure scenarios. Ongoing experimental and analytical studies aim to address these challenges and validate the concept. This EMS topology constitutes a proposal for the FCC-ee Reference Design Phase, with the aim of converging to a stable architecture and assessing its technical feasibility by the end of 2027.

        Speaker: Lucien Porta (CERN)
        EMS_FCCweek26.pdf
        EMS_FCCweek26.pptx
      • 2:30 PM
        FCC-ee Beam Transfer Systems: Maturity Assessment and Critical Aspect 20m

        This contribution presents the current maturity status of the FCC-ee beam transfer systems work packages for the FCC, covering optics, kickers, and septa from the injector complex up to the collider ring.

        A common maturity framework, aligned with the FCC project schedule, is applied across all systems to identify the current level of development, the main technical challenges, and the activities required to progress.

        In parallel, a criticality assessment indicates where to focus resources to meet the Reference Design deliverables.

        Speaker: Giorgia Favia (CERN)
        FCCee_ABT_maturity.pdf
        FCCee_ABT_maturity.pptx
    • 1:30 PM → 5:00 PM
      Governance: SAC: Scientific Advisory Committee (closed session) F3005

      F3005
    • 1:30 PM → 3:00 PM
      Joint effort PED & accelerators: Machine Detector Interface (ii) F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Fabrizio Palla (Universita & INFN Pisa (IT))
      • 1:30 PM
        Injection and SR backgrounds and SuperKEKB benchmarking 25m

        The electron–positron Future Circular Collider (FCC-ee) is a proposed high-energy lepton collider designed to achieve unprecedented luminosity and precision in the study of fundamental particle physics. To fully exploit this potential, it is crucial to control beam-induced experimental backgrounds to ensure safe operation and optimal detector performance. This is particularly challenging due to complex operational requirements, such as the top-up injection process, which introduces unavoidable beam losses while detectors are taking data, and the 50 MW of synchrotron radiation emitted per beam, which can partially reach the detectors if not properly collimated or intercepted with masking and shieldings. We present studies of these two background sources: for injection, we track losses from their source to the detector using a multi-step simulation framework; for synchrotron radiation, we assess the performance of a dedicated collimation system protecting the interaction region under several conditions.
        We also discuss the benchmarking of the tracking tools employed, with the injection background case validated against experimental data collected at the operational SuperKEKB electron-positron collider.

        Speaker: Giulia Nigrelli (Sapienza Universita, INFN-LNF, CERN)
        FCCWeek2026_GN.pdf
        FCCWeek2026_GN.pptx
      • 1:55 PM
        Generator level IPC studies 15m
        Speaker: Jan Eysermans (Massachusetts Inst. of Technology (US))
        IPC_status_FCCWeek_11062026.pdf
      • 2:10 PM
        Beam-induced backgrounds in vertex detector and silicon wrapper 20m

        Beam-induced backgrounds (BIBs) are a critical constraint for FCC-ee operation, particularly at the Z pole with instantaneous luminosities reaching $1.4\times 10^{36} \text{cm}^{-2}\text{s}^{-1}$. BIBs strongly influence the design of the machine–detector interface (MDI), as well as the layout and technology choices of detectors.
        Focusing on the vertex detector and silicon wrapper, this contribution presents detailed simulations of the dominant BIB sources, namely incoherent pair creation, synchrotron radiation, and injection-related backgrounds. Resulting hit rates are evaluated for each detector layer, together with derived pixel occupancies and data bandwidth requirements. The study further assesses the impact of design variations of the vertex detector, such as different detector layouts, the reduction of the radius of the innermost layer, and different assumptions on the depletion region within the sensor volume.
        Lastly, the cluster size of the incoherent pair creation background is investigated for various sensor designs, deriving realistic hit rate requirements for vertex detectors at FCC-ee.

        Speaker: Armin Ilg (University of Zurich)
        Vertex backgrounds_FCC Week 2026_Armin Ilg.pdf
      • 2:30 PM
        Radiation levels in the FCCee detector, MDI, and experimental insertions 15m
        Speaker: Alessandro Frasca
        FLUKA_studies_for_the_FCC-ee_MDI.pdf
        FLUKA_studies_for_the_FCC-ee_MDI.pptx
      • 2:45 PM
        Detector backgrounds in Central Tracking Detectors 15m

        We will review current estimates of the background conditions in the central trackers of detectors at FCCee, comparing various background sources, MDI designs, and tracker technologies.

        Speaker: Daniel Jeans
        FCCweek2026-jeans.pdf
    • 1:30 PM → 3:00 PM
      Physics, Experiments and Detectors: Joint session Physics Software and Computing & Detectors F4050 Pieni juhlasali

      F4050 Pieni juhlasali
      Convener: Chris Rasmussen (Brookhaven National Laboratory (US))
    • 1:30 PM → 3:00 PM
      Superconducting Radio Frequency: SRF Technology Developments F3020

      F3020
      Convener: Mr Alan Wheelhouse (ASTeC, STFC)
      • 1:30 PM
        SRF research at HZB with potential use for FCC cavities 18m

        For about 25 years HZB and formerly BESSY have conducted research on superconducting radio frequency (SRF) cavities mainly for continous-wave applications, like Energy Recovery Linacs, Free-Electron-Lasers and light source storage rings. In more recent years, HZB also joined EU Horizon funded programms and further third party funding to work on the characterization of new SRF materials coatings, as Nb3Sn, researched recipies for Niobium cavity treatment to improve the surface resistance and also develops ancillary components to reduce the required RF power installation by detuning compensation with fast ferro-electric tuners (FE-FRT). In this contribution, we will give an overview on the most recent research conducted at HZB, of which future FCC cavities may profit from.
        The progress on growing Nb3Sn layers by the bronze route method, the insitu mid-temperature baking of Nb cavities and the FE-FRT developed for microphonics compensation within the EU Horizon iSAS programme* will be presented here.

        Speaker: Axel Neumann (Helmholtz-Zentrum Berlin)
        ANeumann_FCCWeek_Helsinki_110626.pdf
        ANeumann_FCCWeek_Helsinki_110626.pptx
      • 1:48 PM
        Status of RF design (cavities, HOM damping) 18m
        Speaker: Shahnam Gorgi Zadeh (CERN)
        Status of RF design (cavities, HOM damping).pdf
        Status of RF design (cavities, HOM damping).pptx
      • 2:06 PM
        Advanced Materials for Superconducting RF Technology 18m

        This presentation will give an overview of recent R&D at Cornell on advanced materials for next-generation SRF technology, showing the potential for substantial enhancement in cavity performance.

        Speaker: Matthias Liepe
        Liepe_FCC_2026.pdf
        Liepe_FCC_2026.pptx
      • 2:24 PM
        R&D for high-Q 800 MHz SRF cavities for FCC-ee 18m

        800 MHz bulk niobium superconducting RF cavities are a fundamental, and sizeable, component of the FCC machine at all operating points. In the Booster, for Z, W, and H operating points, there are 112 cavities in 28 cryomodules. For TTbar operation, there will be a total of 448 cavities in the booster in 112 cryomodules, The FCC cavity performance specifications currently sit at the upper limit of what present-day techniques can achieve, and still incur a high RF power budget, in addition to generating substantial static and dynamic heat loads per cavity, driving up cryogenic costs. In order to deliver the most cost-effective and feasible version of the FCC, R&D efforts on 800 MHz SRF cavities and cryomodules have begun, focusing on advanced surface treatments for bulk niobium on 5-cell and single-cell 800 MHz prototypes. FNAL is taking delivery of the first of these prototypes from CERN immanently, and we present the proposed experimental plan. In addition, FNAL is collaborating with CERN on the mechanical design of the 6-cell 800 MHz cavities and cryomodules, based on experience with PIP-II designs and production. We thus also present updates and future plans for 800 MHz SRF CM R&D for FCC.

        Speaker: Kellen McGee (Fermi National Accelerator Laboratory)
        800MHz_RnD_FCCee_FCCWeek2026.pdf
        800MHz_RnD_FCCee_FCCWeek2026.pptx
      • 2:42 PM
        High power impulse magnetron sputtering and its relevance for fabricating coating-based superconducting radio-frequency cavities 18m

        High power impulse magnetron sputtering (HiPIMS) is a physical vapor deposition method which turns a conventional magnetron source into an ion source. This is achieved by applying power to a sputtering cathode in the form of short (typically <200 µs) unipolar pulses of low frequency (<1 kHz) to create an ultra-dense plasma where electron-impact ionization collisions become effectively dominant. Since its inception in 1999, HiPIMS has been shown to offer distinct advantages over conventional sputtering-based methods (e.g., direct current magnetron sputtering), including growth of dense coatings at low temperatures without the need for excessive noble-gas ion bombardment, control of film microstructure and phase composition, and deposition of dense and uniform films on complex-shaped substrates. The latter is extremely relevant for fabricating coating-based superconducting radio-frequency (SRF) cavities. In the present contribution, we will briefly review the above-described features of HiPIMS and show that they can be used for depositing Nb coatings on Cu SRF cavities. The empirical experimental observations pertaining to the Nb-Cu film-substrate system, will be complemented by atomistic modelling of the deposition process using Molecular Dynamics with the purpose of gaining physical insight into the underlying structure-forming processes that control film morphological evolution on complex-shaped substrates.

        Speaker: Kostas Sarakinos (University of Helsinki)
        FCC2026_Kostas Sarakinos .pdf
        FCC2026_Kostas Sarakinos .pptx
    • 3:00 PM → 3:30 PM
      Coffee break 30m Agora, Civis and Aula Rectoria

      Agora, Civis and Aula Rectoria
    • 3:30 PM → 5:00 PM
      Accelerator Technical Design: Production and Technology F3017

      F3017
      Convener: Joao Barreiro Guimaraes Da Costa (Chinese Academy of Sciences (CN))
      • 3:30 PM
        CEPC magnet automatic production line 20m
        Speaker: Zhihui Mu (Insititute of High Energy Physics,CAS)
        0610-CEPC Booster magnet Prototype & Production Line.pdf
        0610-CEPC Booster magnet Prototype & Production Line.pptx
      • 3:50 PM
        CEPC vacuum system optimization and NEG coating automatic fabrication line 20m

        This presentation outlines the optimization of the vacuum system for the Circular Electron Positron Collider (CEPC) and the core R&D and construction progress of its supporting NEG (Non-Evaporable Getter) coating automated production line, which is the key implementation carrier of the project’s large-scale vacuum chamber manufacturing. The CEPC, featuring a 306-kilometer, encompasses linear accelerators, damping rings, and collision experiments. The vacuum chambers, constructed from extruded Cu alloys for collider rings, must operate stably under synchrotron radiation (SR) environments.
        One automated production line are under installation and commissioning. the line integrates NEG coating, heating layer spraying. and is fully compatible with the processing of ultra-large-size vacuum chambers (11.4 m in length, Φ56 mm in diameter). the NEG coating, with standardized activation at 180°C for 24 hours to meet the requirement of Secondary Electron Yield (SEY) < 1.2; the <0.5 mm-thick ceramic/metal composite heating layer, developed via atmospheric plasma spraying, is integrated into the production line, enabling in-situ baking and re-activation at 300°C to resolve non-resistant of SR issues with traditional polyimide heating tapes. Prototype tests of the core equipment (NEG coating furnaces) and key components (heating layer prototypes) have been successfully completed, verifying the technical feasibility and stability of the production line.
        The HEPS project confirms in-house NEG coatings as a mature and reliable solution. The CEPC production line is scalable for large-scale colliders (e.g., FCC-ee), requiring only minor adjustments for future projects. This development establishes a robust foundation for next-generation particle accelerators.

        Speaker: Dr Yongsheng Ma
        CEPC vacuum system optimization and NEG coating automatic fabrication line--2026 FCC week.pdf
        CEPC vacuum system optimization and NEG coating automatic fabrication line--2026 FCC week.pptx
      • 4:10 PM
        Status of the Arc BPM design 20m

        Given the size of the system, and importance for FCC operation, the studies on the Beam Position Monitor system is one of the main efforts of the Beam Instrumentation team. This talk presents recent progress in electromagnetic pick-up design, along with preliminary discussion on expected performance in relation to operational requirements. Considerations on system integration into the accelerator environment are also discussed.

        Speaker: Kacper Lasocha (CERN)
        FCC_week_bpm_26.pdf
        FCC_week_bpm_26.pptx
      • 4:30 PM
        CEPC SRF Development 20m

        The Circular Electron Positron Collider (CEPC), which was proposed by the IHEP in 2012, is a 100-km collider with a center-of-mass energy of 90–240 GeV for Z, W, and Higgs bosons. CEPC is capable of producing 1000000 Higgs bosons within 10 years and is regarded as a Higgs factory. The SRF system of the CEPC is critical and challenging owing to the wide range of beam energies and currents, which has been introduced in the Technical Design Report (TDR) in 2024. This contribution will demonstrate the research progress of CEPC SRF, including design, key technology, development of prototypes, etc. Especially, the 650 MHz SRF cryomodule for the collider ring will be highlighted, which is under development. Besides, thin-film SRF cavity is also investigated.

        Speaker: Prof. Peng Sha (IHEP)
        CEPC SRF development - 20260611.pdf
        CEPC SRF development - 20260611.pptx
    • 3:30 PM → 5:00 PM
      FCC-ee Injector: Injector Machine - Specific Designs and R&D Progress F3020

      F3020
      Convener: Ursula Helga Van Rienen
    • 3:30 PM → 5:00 PM
      Joint effort PED & accelerators: EPOL (ii) F3003 Tekla Hultin

      F3003 Tekla Hultin
      Convener: Jacqueline Keintzel (CERN)
      • 3:30 PM
        FCC-ee polarimeter design update 22m

        Updates on the design of the inverse Compton polarimeter for the FCCee LCC optics are presented, highlighting progress made and remaining challenges. Extensive simulations of the polarimeter have been performed with BDSIM, a Monte Carlo-based particle tracking tool designed for accelerator and beamline modelling. Outputs of the simulations have been put through a digitisation algorithm to replicate the output of the real silicon sensor as closely as possible. The model has been used to predict the precision of the polarisation measurement, primarily for measuring the beam energy via resonant depolarisation, to determine whether it is feasible to reach the requirements of the physics aims of the project.

        Speaker: Jasper Burvill (The University of Manchester (GB))
        2026_06_11_FCC_Week.pdf
        2026_06_11_FCC_Week.pdf
        2026_06_11_FCC_Week.pptx
      • 3:52 PM
        Status of depolarizer 22m

        Resonant kicker designs with peak shunt impedance at $80~\mathrm{MHz}$, $160~\mathrm{MHz}$ and $320~\mathrm{MHz}$ are compared with the baseline design of a matched stripline. The reduced relative bandwidth of these higher frequency kickers offers advantages for the design of the needed RF driving hardware. Higher-order-mode couplers are foreseen to damp beam-induced voltage. The signals on these can be used for monitoring purposes, time aligning kicks and to generate interlocks in case of loss of synchronization between probe bunches and depolarizer kicks.

        Speaker: Daniel Sittard (CERN and Karlsruhe Institute of Technology (KIT))
        sittard_status_of_depolarizer.pdf
        sittard_status_of_depolarizer.pptx
      • 4:14 PM
        Polarization studies on the BEPCII storage ring and CEPC 22m

        A laser-Compton polarimeter has been set up at the BEPCII electron storage ring, which will facilitate R&D of Compton polarimetry, resonant depolarization and radiative depolarization effects, in the content of future circular colliders. The status and future plans of this instrument will be reported. Besides, recent progress in the beam polarization studies for CEPC will also discussed.

        Speaker: Zhe Duan (IHEP)
        CEPC_polarization_studies_on_the_BEPCII_storage_ring_and_CEPC_v5.pdf
        CEPC_polarization_studies_on_the_BEPCII_storage_ring_and_CEPC_v5.pptx
      • 4:36 PM
        Energy calibration: observations as we enter the Reference Design Phase 22m
        Speaker: Guy Wilkinson (University of Oxford (GB))
        Helsinki_EPOL_Wilkinson.pdf
  • Fri, June 12