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- Indico Weeks View
We are delighted to extend a warm invitation to the tenth edition of the Future Circular Collider (FCC) Conference, scheduled to unfold in the vibrant city of San Francisco, United States, from June 10 to 14, 2024. The meeting is jointly co-organized with Argonne National Laboratory (ANL), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), SLAC National Accelerator Laboratory, Fermi National Accelerator Laboratory (FNAL), Thomas Jefferson National Accelerator Facility (JLAB), and the US Department of Energy (DOE) and with the generous support of the University of California Berkeley, University of California Davis, University of California Irvine, University of California Santa Cruz, and California State University East Bay.
This significant gathering, collaboratively organized with the EU-funded H2020 FCCIS project, serves as a convergence point for international experts spanning diverse domains. Together, we will advance the feasibility study for a visionary post-LHC research infrastructure at CERN.
Building on the outcomes of the FCC midterm review, a preferred layout and placement scenario have been identified, capable of accommodating both FCC-ee and FCC-hh, without compromising the scientific excellence inherent in each proposed research programme.
We invite you to be part of the FCC Week 2024, contributing to a comprehensive review of the FCC's progress - a pivotal juncture in our journey toward completing the FCC Feasibility Study by 2025.
Gain valuable insights into achievements to date, confront challenges faced, and delve into the strategic roadmap for forthcoming phases.
Engage in dynamic discussions with key stakeholders and play a role in shaping the trajectory of this groundbreaking initiative.
Plenary and Parallel Sessions:
Connect with fellow researchers, academics, and professionals across dedicated sessions covering physics, experiments, machine design, technologies, infrastructures, and civil engineering.
The first day will feature plenary keynote presentations by top-ranking international speakers providing an overview of ongoing activities across all study areas.
Stay informed about updated boundary conditions, machine parameters, and the captivating physics potential of the FCC integrated program spanning decades.
Parallel sessions will delve into specific domains, fostering collaboration, providing opportunities to share your research, and faciliting lasting connections with the global particle physics community.
Poster Sessions: Showcase your research through poster sessions, immersing yourself in cutting-edge projects in particle physics, accelerator physics and technology.
Explore the latest advancements and draw inspiration from the diverse range of research on display.
Social Events and Cultural Experiences:
Take a breather from the scientific discussions and partake in social events designed to foster a sense of community. Immerse yourself in local culture, cuisine, and entertainment, creating memorable experiences beyond the lecture halls and workshops.
On Tuesday 11 June, come join us at the Exploratorium (Pier 15) for a mind-blowing event where we delve into the mysteries of our universe! From the Higgs boson to dark matter, we will explore the frontiers of particle physics and how international collaborations tackle these profound questions. As we journey through these discoveries, we will also discuss how advances in particle physics contribute to technological innovations and societal progress.
Find out more: https://fccweek2024.web.cern.ch/PublicEvent.html
Mark your calendars for this unparalleled opportunity to be part of the ongoing evolution in particle physics.
Join us at FCC Week 2024, where collaboration meets innovation to shape the future of scientific exploration.
We eagerly anticipate your active participation!
FCCIS – The Future Circular Collider Innovation Study. This INFRADEV Research and Innovation Action project receives funding from the European Union’s H2020 Framework Programme under grant agreement no. 951754. |
A summary of a workshop (May 2024) dedicated to QCD physics of relevance for Higgs measurements at the FCC-ee will be presented.
We show that the FCC-ee will have sensitivity to the MSSM electroweak sector that is complementary to the LHC, through the precision Z-boson measurements. Our results provide added motivation and quantitative targets for the desired systematic uncertainty on this measurement.
In view of the FCC feasibility study report, the Safety WP is tasked with the editorial of a Safety Concept. This report will detail all the risks associated with the future activities of the FCC-ee machine during the civil engineering construction, installation and operation phases.
The outcome of the safety concept leans of the results of several safety studies performed by the HSE Unit and the implementation of safety-relevant systems which are designed and proposed by other WPs in the Technical Infrastructure Pillar.
This presentation will provide a general overview of the current status of the Safety concept, as well as presenting the results of the most recent safety studies that were performed in the last year, providing the scientific support to the safety concept.
The safety systems for the protection of personnel in the CERN accelerator complex are designed, installed, and maintained by the EN-AA group. The group relies on industrial partners and supports, whenever possible, off-the-shelf solutions complemented with specific studies and developments when needed. This talk gives an overview of the safety systems required by the FCC safety concept, such as access control, fire and ODH detection, and evacuation systems. Use of proven solutions is discussed, new challenges resulting from FCC specificities highlighted and areas requiring further attention identified.
The radiation protection studies shall ensure that the proposed design of FCCee is compatible with the objectives and constraints for radiological protection of the personnel and the environment. An assessment of the radiological parameters, such as the levels of prompt and residual radiation and activation, allows to evaluate their impact during the operation and maintenance of the facilities.
The studies further provide input, the expected released activities through air and water, to the radiological environmental impact study. This allows to confirm that the design of the FCCee will align with the environmental objectives and constraints for the protection of the public.
FLUKA Monte Carlo simulations are performed to confirm that the envisaged design of the civil engineering infrastructure minimizes the prompt and residual radiation levels in areas where access is required. Either during maintenance periods, i.e. in the arc, at beam and beamstrahlung dump locations, around the positron target or during operation periods, i.e in the service caverns, the klystron galleries or the surface facilities.
A first evaluation of material activation is also conducted, as it involves various types of constraints. The activation of high volume accelerator components (such as yokes, coils, photon absorbers, synchrotron radiation shielding) is evaluated to assess the potential radioactive waste production. This study is still in its preliminary stage, and will help to select materials that can be removed from regulatory control within a foreseeable timespan after the FCCee operation.
We will present an overview of the conducted studies and outcomes and present an outlook on what will be important in terms of radiation protection optimisation in the ongoing feasibility study and as the FCCee project further develops.
The availability and safety of the Future Circular Collider (FCC) are critical factors for its operation. To enhance these parameters cost-effectively, the FCC Robotic System (FCCRS) has been conceived and it is under development during the last years. The FCCRS comprises a Remote Maintenance and Inspection System (RMIS) and a Survayance and Emergency Shuttle (SES). This system will significantly improve machine availability, tripling the allowable mean time between failures for critical infrastructure. Integral to the FCC's safety strategy, the SES will minimize emergency intervention times and protect workers from hazardous situations. This presentation will also share insights from previous robotic interventions across the CERN complex, providing conclusions and recommendations for future machine and infrastructure design, as well as intervention protocols.
The talk will provide an overview of the model identified to transport people from the surface to their place of work in the tunnel and vice versa.
The transport concept is currently based on personnel lifts linking the surface to the underground facilities and bespoke automated vehicles running in the accelerator tunnel and the service caverns.
During the presentation, the safety requirements as well as the technical specifications that these handling systems shall respect will be described; the talk will also cover the main features of the transport model that are required to guarantee an efficient transport of people in normal conditions and a safe evacuation of the personnel in case of emergency.
The presentation will provide an update on the concepts for the people transport vehicle and the magnet transport vehicle. It will also include new information on the logistics study for the transport and installation of the collider and booster ring in the underground tunnel.
The concept for the people transport vehicle is specifically designed to navigate the narrow tunnel of the FCC. The presentation will provide information on its design features, including vehicle dimensions, capacity for personnel and material, motorization, battery, and autonomous driving capabilities.
The general concept for the magnet transport vehicle has undergone further development, with a focus on the gripping systems adapted to the different types of magnets. The presentation will show the systems for the magnets used in the collider ring and booster ring.
Additionally, the presentation will share results of new experiments conducted as part of the logistics study for the installation of the collider and booster ring. These experiments were aimed at addressing the bottleneck caused by the shaft crane.
Building the FCC tunnel, installing and aligning each component and experiment of the machine at the intended location will be a challenging task relying notably on the quality and accuracy of the geodetic infrastructure.
In collaboration with ETHZ, HEIG-VD, IGN and Swisstopo the development of the new geodetic infrastructure for the FCC has continued over the past year. Efforts were centered on the implementation of the CERN Geodetic Reference Frame, through the construction of the primary surface geodetic network and on the improvement of the local geoid model. Additionally, desk studies on methodologies and instruments for gravity field determination and on calibration, control and test facilities of the geodetic equipment needed during construction and operation of the FCC were also carried out.
The presentation will cover the task accomplished during the past year and give an overview of the remaining challenges.
To reach integrated luminosity goals, the FCC-ee must be operational for minimum 80% of the scheduled 185 physics days each year. For comparison, the LHC achieved 77% in Run 2, 2016-2018. There are additional challenges in operation and maintenance of the FCC-ee due to its scale, complexity and ambitious technical objectives. Availability is therefore a significant risk to physics deliverables, and merits consideration especially in the early stage of the design process. This presentation outlines recent key findings from the FCC-ee availability study following new information from the Mid Term report and input from technical infrastructures. Contributions are as follows: (I) The baseline FCC-ee Operation Cycle is presented, including key constraints imposed by the need for energy calibration by resonant depolarisation. (II) For the first time, the relationship between availability and integrated luminosity imposed by this operation cycle is formalised and quantified in Monte Carlo simulation. (III) Updates to the RF availability model are illustrated, including estimation of the minimum redundancy required to reach luminosity targets. (IV) Compelling solutions to overcome shortcomings in the baseline FCC-ee operation cycle are discussed, and powerful opportunities for R&D are highlighted.
This talk offers an overview of the sub-surface civil engineering design for the Future Circular Collider. It encompasses various topics crucial to the project's progress, including feedback from the Mid-Term Review, analysis of the associated cost and schedule impacts and ongoing studies focused on tunnel ventilation and safety. Additionally, case studies drawn from other tunnelling projects provide valuable insights and lessons learned. Moreover, it includes discussions with consultants and contractors aimed at gaining deeper technical understanding and ensuring the effective execution of the FCC construction.
Following the outcomes of the collaboration between CERN and Fermilab (US Department of Energy), this talk will present the progress on the design and preparation of all 8 FCC surface sites.
The presentation will discuss the various inputs considered to demonstrate the feasibility and adaptability of surface sites in accordance with technical, environmental, and urban constraints. It will also provide some thoughts for future studies on the FCC buildings.
This presentation will recap the objectives of the Subsurface Site investigations (SSI) and the scope of the original campaign when it was released to tender in October 2023. It will discuss the results of the tender and detail the amendments to the original strategy based on these results and the availability of new geological data since 2023 and present the provisional programme for the SSI. Following this, it will describe the results that are expected from the campaign and indicate potential modifications to the baseline tunnel configurations and elevation arising from new data. Lastly, it will look at the site investigation campaigns that will follow this campaign and look at parallel studies that will be undertaken to reduce uncertainty in the design of the future FCC underground infrastructure.
We report on a conceptual design for a noble-liquid-based EM endcap
calorimeter, where the absorber plates and readout electrodes are
arranged in a turbine-like geometry. This design allows for
frequent shower sampling and highly granular readout, without
introducing cracks in phi. Furthermore, it can be constructed from multiple
copies of a small number of absorber and readout board designs. The implementation
of this geometry in the ALLEGRO detector simulation and initial simulation results will
be presented.
Following the priority research directions for calorimetry documented in the DOE HEP basic research needs for instruments the Caltech HEP Crystal Lab has been actively investigating novel inorganic scintillators along the following three directions. Fast and radiation hard inorganic scintillators to face the challenge of severe radiation environment expected by future HEP experiments at hadron colliders, such as the HL‐LHC and a 10 TeV pCM collider, where radiation damage is induced by ionization dose, protons and neutrons. Ultrafast inorganic scintillators to face the challenge of unprecedented event rate expected by future HEP experiments searching for rare decays, such as Mu2e‐II, and ultrafast time of flight (TOF) system at colliders. Cost‐effective inorganic scintillators for the homogeneous hadron calorimeter (HHCAL) concept to face the challenge of both electromagnetic and jet mass resolutions required by the proposed Higgs factory. We report recent progress in all these directions, such as LuAG:Ce ceramic fibers for the RADiCAL proposal, Lu2O3:Yb ceramics for TOF and ABS:Ce and DSB:Ce glass scintillators for HHCAL and the CalVision proposal. The result of this investigation may also benefit nuclear physics experiments, GHz hard X‐ray imaging, medical imaging and homeland security applications.
Follow up the up-to-date requirements from the different stakeholders (cooling, HVAC, electrical supply, transport, safety systems, and machine systems). The integration team classified and optimized the space which will be used in the underground infrastructure. The 3D integration models were updated with the new occupation requests on the machine tunnel and the arcs, experimental caverns, and service caverns, and all the rest support underground infrastructure.
At this stage of the feasibility study of FCC, few challenges were identified, and the electrical network has a role to play in improving them.
Indeed, the study highlighted the need to use as little space as possible: on surface sites to limit the environmental impact, but underground as well to limit the civil engineering cost. In this sense, the electrical network is designed to reduce its footprint. Some improvements are developed for transmission and distribution substations, that are initially big space consumers, to reduce their size and location.
Regarding the electrical network itself, it is developed to improve the network stability and its immunity from external disturbances. The power quality needs also to be managed, for this way, some equipment needs to be installed and design all around the machine. Their size, position and technology are studied to be optimized.
The aim of this presentation is to show the progress done on the optimization of the electrical network for the FCC, using new technologies.
The talk provides the latest advancements in evaluating optimal powering solutions for the FCC-ee.
To achieve a global optimum which balances Capital and Operation Expenditures (CAPEX and OPEX) a holistic approach is needed. Several equipment designs such as cables, power converters, cooling and ventilation systems, magnet, and alcoves volumes are tightly related and CAPEX+OPEX compromises must be evaluated. For this purpose, a global optimization tool has been developed, integrating models from different expert groups at CERN. This tool enables the identification of optimal design trade-offs between accelerator subsystems by minimizing total expenditure.
The global optimization tool is utilized to illustrate the overall impact of selecting different number of alcoves. It provides the optimal number of alcoves based on the precision of current models.
Intense positron source is one of a crucial component for future electron positron colliders. Although each project, FCC, ILC, CLIC, CEPC, C3 uses many different technologies for main accelerator, requirement and present design of the positron source are very similar. Recently, under the support of CHART program and FCC feasibility study, positron source design for the FCC has progress rapidly. At the same time, design work and prototype manufacturing of positron source for ILC started using the five years grant from MEXT since 2023. To maximize synergy effect, we have strengthen the collaboration and mutual discussion.
In addition, experimental works are very important to validate the design and simulation for future positron source. The positron source for the SuperKEKB is the only one machine which can provide such opportunity in the world now.
In this talk, present status and recent progress of the positron source will be summarized along with recent joint experiment at KEK using positron source for SuperKEKB.
The CERN proposed $e^+e^-$ Future Circular Collider (FCC-ee) is designed as an electroweak, flavour, Higgs, and top factory with unprecedented luminosities. Many measurements at the FCC-ee will rely on the precise determination of the vertices, measured by dedicated vertex detectors, and the Silicon Wrapper at about two meters in radius, improving momentum resolution, providing precise angular acceptance definition, with the additional possibility of timing information.
This contribution discusses the capabilities of the IDEA tracking systems, using DD4hep full simulation, and an optimized layout of the Silicon Wrapper. We will further present a possible layout beyond this baseline design, introducing a novel concept for an ultra-light vertex detector using curved wafer-scale MAPS, and discuss the overall optimization.
What's Left to Discover? Our Unknown Universe
Date: Tuesday 11th June 2024
Time: 19:00 to 21:00 PDT [doors open at 18:30]
Location: Exploratorium, Kanbar Forum
https://fccweek2024.web.cern.ch/PublicEvent.html
We will present the update of the magnet parameters resulting from the global optimization of the magnet circuits carried out this year in collaboration with our colleagues of the CERN power converter group. We will show how the magnet cross sections have consequently evolved and list the next steps for the magnet development until the end of the feasibility study and beyond.
Update on the design of the high energy booster magnets. We will cover:
- developments on the low field dipole, a key factor in defining the injection energy for the booster.
- parameters and cross sections of magnets to meet the requirements of the v.24 HEB optics baseline.
- early results factoring the global optimisation in collaboration with CERN power converter group.
The talk addresses different aspects of magnet powering circuit configuration of the FCCee.
The number of circuits has a big impact on the performance of the beam (controllability in primis); however, the greater the number of circuits, the higher the total cost.
Accelerator controllability, optics granularity and availability specifications directly impact the number of circuits and the performance requirements of the power converters powering the magnets.
This presentation showcases these parameters and their impact on the total expenditure.
The FCC-ee arc half-cell mock-up project is continuing its engineering design phase and entering the manufacturing, installation, and testing phase. The production of a 1:1 scale mock-up has been launched and the installation of the first version is scheduled for Q1 2025. The main idea is to have a modular mock-up that can accommodate systems from other teams: robots, magnets, safety systems, etc. Meanwhile, design and optimisation studies are progressing on the supporting structures of the booster and collider, and on the interfaces between the main systems. The project team is also developing a Short Straight Section demonstrator, combining experimental measurements and simulations to assess the vibrational contribution of the various elements such as the feet, the support, the magnets, etc.
We present the results of the wake field analyses for different geometries of the IR beam pipe elements like bellows, BPMs, SR mask including beam pipe shape. We found a possibility how to decrease and capture wake fields generated by colliding beams in the interaction region. This optimization study will be useful for the FCC-ee IR beam pipe design.
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, H, and ttbar operating points, there are 24, 56, 112, and 600 of these cavities respectively, with an additional 488 in the collider ring for ttbar operation. 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 thereby feasible version of the FCC, R&D efforts on 800 MHz RF cavities have begun, focusing on advanced surface treatments on 5-cell and single-cell 800 MHz prototypes. We report the first cold test results of these prototypes, and propose a course for future development.
Following up the updates on RF section studies, where we have a new design of the 400MHz and 800 MHz cryogenics modules. The integration studies are considering boundaries in term of space limitations and design requirements, such as underground infrastructures (access shaft, connection tunnels, etc.), straight section length, cryogenics modules length, general services (electrical, cooling and ventilation), transport reserved volumes. All systems shall fit in the 5.5m inner diameter tunnel.
The RF systems of the FCC-ee are expected to be the primary consumers of power and energy. With an estimated power consumption exceeding 100 MW, it is crucial to design an efficient and reliable powering system that can deliver power from the AC network to the klystron gallery.
A critical component of the RF powering system is the main power converter. The use of a centralized high-voltage Modular Multilevel Converter (MMC) as the main conversion device is being analysed for this purpose. This converter topology offers high efficiency and reliability, making it a standard in the industry. The converter's topology, operation, and an update of the volume and cost estimation will be presented.
In terms of distribution, a single-bus approach is proposed. To meet the individual control and protection requirements of each klystron, a strategy based on trimming converters and series switches will be presented, providing details on the control strategy. Additionally, the powering of the solid-state RF amplifiers, if needed, will be discussed, highlighting the main challenges of supplying this type of amplifier.
Finally, the presentation will provide a cost and volume estimation of the proposed powering strategy, introducing several proposals for optimizing the system to minimize overall capital and operational expenditures (CAPEX and OPEX).
The FCC collider and injection complex call for a diverse set of injection and extraction septa. This presentation will summarise the principal technological choices for each of them, and will derive the implications from the technology choices on the required infrastructure. For the more challenging systems, alternative approaches will be scrutinised and areas where further development is needed will be identified.
For injection, extraction and beam disposal fast pulsed systems are needed throughout the FCC-ee complex. This presentation outlines the various kicker systems needed to transport the lepton beams from the electron source up to the collider dump system. The individual system requirements are presented, and the choice of design parameters and technology options for both beamline elements and pulse generators are discussed. Potential challenges are highlighted, together with areas for R&D and implications on infrastructure.
The Future Circular Collider electron-positron (FCC-ee) is a proposed high-energy lepton collider that aims to reach unprecedented precision in the measurements of fundamental particles. However, several beam related processes produce particles in the Machine-Detector Interface (MDI) region, which can adversely affect the measurements' accuracy. This contribution presents a study of the beam-induced backgrounds at FCC-ee. The study uses the turnkey software Key4HEP to estimate the occupancy levels induced by beam-beam interactions, beam losses and Synchrotron Radiation in several sub-detectors of CLD, IDEA and ALLEGRO detector concepts.
The Electron-Ion Collider (EIC) is an advanced particle accelerator designed to explore matter's fundamental structure at the subatomic scale. It collides high-energy polarized electron beams with ions, like protons or lead nuclei, enabling scientists to scrutinize quark and gluon interactions. The EIC's unique setup provides a platform to study these interactions within atomic nuclei, shedding light on nuclear matter and extreme conditions in the universe. Collaboration among multiple institutions drives the construction and operation of the EIC, with the overarching goal of advancing our understanding of the fundamental forces and particles.
The EIC plans to operate at high beam currents and luminosities to probe dense gluon systems and unravel the origins of nucleon mass and spin. However, this strategy increases beam-induced background rates in the ePIC spectrometer located at the interaction point. Notably, synchronous radiation (SR) emitted from the electron beam is a significant source that negatively impacts detector longevity and physics analysis performance.
This talk describes the Monte-Carlo simulation method for the SR background in the ePIC setup at the EIC. It introduces a new framework to accurately model X-ray photons' specular and diffuse reflection on vacuum-metal interfaces. In addition, the framework utilizes the extensive functionalities of Geant4 classes for particle-matter interaction studies. Moreover, the talk presents updated estimates of SR rates in various ePIC subsystems and proposes countermeasures to protect sensitive electronics, ensuring a stable detector operation.
The water cooling system of the FCC is in charge of extracting the heat produced at magnets, cryogenic systems, absorbers, electronics, etc. This presentation provides an overview of the current status of the cooling systems, covering aspects such as thermal load management, thermal load variation over the year and for the different stages of the FCC-ee. The presentation covers also opportunities to reduce water consumption and options to optimize fatal heat utilization. Finally, the evacuation of water with high levels of TDS for the current layout of the FCC is addressed.
The ventilation system of the FCC includes the supply, treatment, and extraction of air in the accelerator complex, including the Arc Tunnel, Alcoves and the caverns and galleries in the Experimental, RF and Technical Points. The air supplied at the FCC must meet safety, humidity and temperature requirements, among others. The ventilation system is also used to extract part of the thermal load produced by the different machines in the underground facilities.
Several working modes are contemplated depending on the conditions of operation of the accelerator, including cases of emergency and access of the personnel for maintenance work. Further key points include air recycling, control implementation of the system and the transitory regime between modes. This presentation addresses these and other topics and provides as an in-depth look at the ventilation system for the FCC.
Starting from the status presented at the FCC Week of 2023, the network concept has now progressed and been updated on the latest users’ requirements and the latest outcomes of the studies.
Some axis of optimization have been explored and analysed to find the optimum result for the high voltage transmission level and the location of the main substations; the operational scenarios and degraded modes for the electrical grid have been defined to allow in most of the circumstances the continuity of FCC operations; it has been developed the concept of the secured network that will supply all the safety-related systems in surface and overall underground and in the tunnel.
Furthermore, it has been defined how to re-use one of the 400 kV connections to RTE grid already available at CERN to supply in future the new facility, and the feasibility study for the installation of a high voltage line in the tunnel is coming to a positive end.
Finally, the updated setup of the network has been tested with the latest load forecast for FCC-hh, to update the projection of the use of the main infrastructure for the future machine.
The aim of this presentation is to provide the update of the studies on the electrical grid of FCC, focusing on the main items mentioned here above.
In recent years, with the advent of power electronics, DC networks have emerged as a promising solution for the distribution of electrical energy. They offer advantages in terms of efficiency, controllability, volume reduction, and integration of energy storage. Given the specific needs of the FCC, DC networks could be utilized to supply power to specific machine components.
On a larger scale, DC networks could facilitate power transfer around the machine's circumference, reducing the required cable size and enhancing control over active and reactive power. However, it is essential to compare DC networks with other AC technologies, such as the Unified Power Flow Controller and the Static Var Compensator, to fully grasp their benefits. At the access point level, DC networks could minimize the number of conversion stages, thereby increasing overall efficiency. Furthermore, the use of high-frequency transformers and DC cables with lower voltage drops could help reduce the required volume.
This presentation will explore the available technologies for constructing such networks and address the primary challenges involved in building the grid. It will also present several proposals for implementing this technology in the FCC, along with an analysis of the advantages and disadvantages of its use.
The 91km long FCC-ee machine raises major challenges in terms of alignment. Size, location, design, manufacturing, and requirements are aspects increasing the difficulty of the alignment process. The effort will also need to be consistent in time, as the installation and initial alignment are only the very beginning of the surveyor’s duty. Monitoring and readjustment represent the major part of the challenge, as thousands of components will need to be followed carefully and regularly in a brand new tunnel. This talk will address these points, highlighting the main difficulties and angles chosen to tackle these challenges. Specific parts will also be covered, like the straight sections, the interaction regions, and the machine-detector interfaces.
Experiments at the future Electron-Ion Collider (EIC) pose stringent requirements on the tracking system for the measurement of the scattered electron and charged particles produced in the collision, as well as the position of the collision point and any decay vertices of hadrons containing heavy quarks. Monolithic Active Pixel Sensors (MAPS) offer the possibility of high granularity in combination with low power consumption and low mass, making them ideally suited for the inner tracker of the EIC detector(s). In this talk, we will discuss the configuration optimizations, selected physics performance metrics, and associated R&D towards the ePIC Silicon Vertex Tracker; a well-integrated, large-acceptance, precision tracking and vertexing solution based on a new generation of MAPS in 65 nm CMOS imaging technology.
OBELIX is a depleted monolithic active pixel sensor developed for the Belle II experiment at the SuperKEKB $e^+e^-$ asymmetric energy collider designed to cope with high particle fluence. The proposed upgrade of the Belle II Vertex Detector (VTX) will use OBELIX sensor on all its 5 layers. The sensor is based on the TJ-Monopix2 design, fabricated in a radiation hard CMOS 180 nm process.
While its pixel matrix is inherited from TJ-Monopix2, the OBELIX periphery is designed from scratch: A 2-stage pixel memory matches Belle II trigger requirements, handling events with hit rates up to 120 MHz/cm$^2$ at a 10 $\mu$s latency without buffer overflow. This logic also handles hit rate spikes of 600 MHz/cm$^2$ and 0.5 $\mu$s duration with less than 0.5% data loss. This tolerance to spikes is necessary to maintain efficiency at the continuous injection scheme of the SuperKEKB collider. In addition, OBELIX includes LDO regulators for supply voltages intending to simplyfy the chip integration into
the detector system.
To improve track reconstruction performance, an additional high precision timing module is included in the periphery of OBELIX. Based on TJ-Monopix2 test results, a time resolution of less than 3 ns is expected. This feature is, however, currently limited to low hit rates and will only be enabled for the outer 3 layers of the VTX.
A new feature for the vertex detector introduced by OBELIX is the possibility to contribute to the trigger. The chip can provide coarse hit information at low latency to the trigger system in order to build decisions based on VTX tracks. The current implementation is intended as a proof of concept. A transmission time of 200 ns is reached by reducing the matrix granularity to only 8 macropixels.
This contribution will focus on the features of the first OBELIX submission ( 'OBELIX-1’ ) chip currently under development. Details on the design and its implementation, as well as results of various performance simulations calibrated with real data from TJ-Monopix2 measurements will be presented.
We will present the latest developments and plans in the Fermilab group on the development of precision tracking detectors for FCC-ee applications. Efforts have been focused on advances towards manufacturing of novel sensors and on the design of sophisticated Application Specific Integrated Circuits (ASICs) required to achieve the ambitious goals of FCC-ee. We will present developments over several directions that aim to advance particle detectors technologies. The talk will cover our developments and plans for Monolithic Active Pixel Sensors for FCC-ee applications in tracking and calorimeters, 3D-integrated sensors and dedicated ASICs, and 4D-tracking sensors. These projects are a result of successful collaborations among many US and international partners, and this collaborative aspects will be also presented.
We propose to conduct research and development on a straw tracker that can be used as an inner tracker for the FCC-ee. The straw tracker offers the advantage of a low material, a crucial factor in minimizing overall inner detector material budget. With the capability to achieve a single-hit resolution of approximately 120 microns per layer, and the potential for up to 100 layers, the straw tracker will play a pivotal role in pattern recognition and particle identification. Each individual straw serves as a standalone unit, facilitating easy removal of a channel in case of a broken sense wire. The electric field is radial symmetric and the hit position resolution is thus independent of the particle's incident angle. Furthermore, the adaptability of the straw tracker design is highlighted by its ability to accommodate straws with different radii in different detector regions.
We will present simulation and optimization studies for a straw tracker using GEANT4. We will also present detailed Garfield simulation of the gas mixture and the resulting raw detector signals.
Low gain avalanche detectors (LGADs) fabricated by Hamamatsu Photonics KK (HPK) and Fondazione Bruno Kessler (FBK) have been evaluated for performance before and after exposure to gamma and proton irradiation. LGADs promise excellent timing resolution, which can mitigate the pileup associated with high luminosity at hadron colliders. Their timing information can also be used to distinguish long-lived particles with resolvable secondary vertices at lepton colliders. The most highly irradiated LGADs at the HL-LHC will be subject $2.5\times10^{15} \mathrm{n}_{\mathrm{eq}}/\mathrm{cm^2}$ of hadron fluence and 2.2 MGy of total ionizing dose during the LHC’s Run 4; their timing performance must tolerate this. HPK and FBK LGADs have been irradiated with 400 and 500 MeV protons respectively up to the Run 4 hadron equivalent fluence. HPK LGADs were also exposed to 2.2 MGy of gamma dose. Measurements of the irradiated LGADs' leakage current, capacitance, charge collection, and timing performance are presented. A timing resolution better than 70 ps is observed for all proton fluences. Charge collection is below 10 fC for the HPK sensors after $(0.74\pm0.22)\times10^{15} \mathrm{n}_{\mathrm{eq}}/\mathrm{cm}^2$, and for the FBK sensors after $(0.75\pm0.20)\times10^{15} \mathrm{n}_{\mathrm{eq}}/\mathrm{cm}^2$ for all operating voltages below 600 V. A set of 2x2 arrays of both the FBK and HPK LGADs were produced to study the inter-pad characteristics. The inter-pad resistance for the HPK LGADs stayed above 10 M$\Omega$ beyond $0.7\times10^{15} \mathrm{n}_{\mathrm{eq}}/\mathrm{cm}^2$, and the inter-pad resistance of the FBK LGADs fell slightly below 1 MOhm after $10^{15} \mathrm{n}_{\mathrm{eq}}/\mathrm{cm}^2$. Observations of the punch-through voltage and inter-pad isolation for fast signals are reported. The gamma irradiated devices show increase in leakage current and loss in inter-pad resistance comparable to those of the proton irradiated sensors, but minimal gain layer degradation.
The precise identification of jets originating from high-energy quarks and gluons is paramount for advancing our understanding of fundamental particles and forces. This study introduces a novel deep learning framework designed to probe the limits of jet classifier models by using generative AI. State-of-the-art generative models called diffusion neural networks are used to create synthetic jet data where we simultaneously estimate the probability density by solving a differential equation. The likelihood ratio built from the probability density is the theoretical optimal classifier. Our research goal is to explore how close state-of-the-art classifier models are to this bound. We find that a state of the art transformer model performs very well, noting increases in true positive rates and decreases in false positive rates, but there is still a gap with respect to the optimal classifier.
In the past few years, the Low Gain Avalanche Detector (LGAD, thin silicon detectors with modest internal gain and extremely good time resolution) technology have been significantly advanced. The first application of this kind of device will be in the ATLAS and CMS timing layers at the HL-LHC. The first prototypes of LGADs produced few years ago within the collaborations did not show sufficient radiation hardness. However, LGADs with radiation hardness up to a fluence of 2.5E15 Neq/cm2 were developed in the last 5 years thanks to a focused R&D effort.
This successful development paves the path for next generation machines (e.g., FCC-hh) that will require radiation tolerance an order (or more) of magnitude greater and at the same time require a better timing and position resolution. The cited requirements are in a high pile-up environment that is not suitable for AC-LGADs which is the most advanced high granularity LGAD prototype.
There are several new LGAD prototypes that are geared towards satisfying all of these requirements as well as radiation hardness, this contribution will give a brief overview on them and the path forward in their development.
The pure gravity mediation model based on anomaly-mediated supersymmetry breaking is among the well-motivated models consistent with the large Higgs mass and the non-observation of supersymmetry at the LHC so far. We focus on a scenario where all the gauginos, including the neutral Wino which is the lightest supersymmetric particle, are within the kinematical reach of the FCC-hh, and study the model through the gaugino production processes. We show that the masses of gauginos, the lifetime of the charged Winos, and the mass spectrum of squarks can be studied in detail by analyzing these processes even if squarks are out of the kinematical reach.
The Standard Model predicts neutrinos to be massless but the observation of neutrino flavor oscillations implies that they are massive particles.
The type I see-saw mechanism has been extensively studied as a promising model of neutrino mass generation in which the existence of right-handed heavy neutrinos (also called heavy neutral leptons, HNLs) is needed to counterbalance the mass of the observed left-handed neutrinos. Precedent studies considered one HNL as a benchmark phenomenological model but at least two HNLs are needed to explain neutrino oscillations and, simultaneously, the baryon asymmetry of the Universe and dark matter generation, thus being able to give a solution to the main open problems of the Standard Model. The case of two generations of HNLs is considered, with a non-diagonal mixing matrix in all three lepton flavors. The analysis is conducted in the context of exploration proposed by the Future Circular Collider (FCC) in its e+e- stage at the Z-pole. The discovery region accessible at FCC-ee has not been previously excluded by other experiments and allows the HNLs to attain long-lived properties. The search is then focused on displaced vertices, and other reconstructed variables, as an indication of HNL interactions in the IDEA detector. From these properties, an excellent background suppression is achieved. The signal significance is evaluated in a wide range of HNL parameter space. This expected sensitivity is compared with the current experimental constraints as well as the expectations from other future projects. The impacts of detector performance on the HNL sensitivity is also discussed.
The planned LUXE experiment at DESY in Hamburg (Germany) stands at the forefront of the investigation into strong-field quantum electrodynamics with high precision. The interaction between electrons or photons and a high-intensity laser generates new electrons, positrons, and photons. The phenomena under examination include non-linear Compton scattering, non-linear Breit-Wheeler pair production, and the trident process. LUXE's primary objective is to measure the dependence of the matter-antimatter pair production rate on laser intensity. Furthermore, the Compton photons generated in the primary interaction offer an avenue for exploring new physics through a beam-dump-type experiment. Such a concept can also be applied for future colliders.
We systematically study potential effects of BSM physics in the e+ e- -> Z H process. To this end we include dimension-6 Standard Model Effective Field Theory operators and work to NLO accuracy in the electro-weak coupling. To capture the full breadth of potential signatures we include virtual and radiative corrections fully-differential, as well as consider polarized and unpolarized electron and positron beams. In this first study we take a closer look on the Higgs trilinear coupling and CP violating operators.
The software description of the ATLAS detector is based on the
GeoModel toolkit, developed in-house for the ATLAS experiment but
released and maintained as a separate package with few dependencies.
A compact SQLite-based exchange format permits the sharing of
geometrical information between applications including visualization,
clash detection, material inventory, database browsing, and
lightweight full G4 simulation. The set of geometrical primitives
is based on a scene graph approach. Shared instancing and volume
parameterization can be used to achieve a low memory footprint.
An interface to the alignment system allows for multithreaded
operation, required for situations in which a detector element is
considered in concurrent threads during different alignment periods.
The geometry tool has been used in ATLAS for over a 20 year period,
and recently expanded to a more comprehensive toolkit for geometry
development, which is portable, friendly, and easily installed. It
is proposed to investigate the use of this toolkit to assemble and
operate a simulation of one or more proposed FCC detector systems.
Particle detectors for future colliders rely on ever more precise charged particle tracking devices, which are supported by structures manufactured from composite materials. The higher luminosity and higher radiation environment present challenges to support structures and cooling of the detectors. An integrated engineering approach for mechanical structures, cooling and at times sensing is required from conceptualization stage of detectors. Engineering methods and research towards such future detectors is presented. Development of integrated cooling and support structure for applications in calorimetry is presented as a part of CalVision collaboration for the proposed IDEA experiment for future Higgs factories. Detectors at electron-positron machines have significantly smaller material budgets and require targeted concepts. Such sensing R&D efforts with carbon fiber composites is also summarized.
We present a study of the impact of arc magnet alignment errors in the FCC-ee V22 @ Z energy lattice. The aim of the study is to provide realistic alignment tolerances. The Python accelerator toolbox PyAT was used to develop a sequence of correction steps to achieve the nominal emittance,
dynamic aperture (DA), and in the end the design luminosity. The correction scheme has been recently optimized and better machine performance demonstrated. A comparison between LOCO and phase advance/RDT optics correction was performed, showing a somewhat better performance of
the latter.
In FCCAnalyses we utilize the powerful event processing abstractions of ROOT RDataFrame in combination with the event data description of the EDM4hep format, resulting in a fast and multi-threaded framework. The FCCAnalyses package also provides a standard library of analyzer functions, the integration of commonly used HEP tools such as FastJet, ONNX, DD4hep, Delphes, ..., and metadata management of centrally or locally produced samples. This makes FCCAnalyses a full fledged solution for a large spectrum of analyses purposes. The proposed poster will present a cheatsheet/manual page of the framework to better inform all FCC colleagues at the conference about its design, implementation, conventions and best practices.
We present an ML-based end-to-end algorithm for adaptive reconstruction in different FCC detectors. The algorithm takes detector hits from different subdetectors as input and reconstructs higher-level objects. For this, it exploits a geometric graph neural network, trained with object condensation, a graph segmentation technique. We apply this approach to study the performance of pattern recognition in the IDEA detector using hits from the pixel vertex detector and the drift chamber. We also build particle candidates from detector hits and tracks in the CLD detector. Our algorithm outperforms current baselines in efficiency and energy reconstruction, and allows pattern recognition in the IDEA detector. This approach is easily adaptable to new geometries and therefore opens the door to reconstruction performance-aware detector optimization.
Key4hep is a framework which aims at integrating all physics software of the future colliders. The proposed poster will present a "Cheatsheet" of Key4hep to better inform all FCC colleagues at the conference about its design, implementation, conventions and best practices. The focus will be mainly held on the four pillars of Key4hep, which are: Gaudi --- event processing framework with services, algorithms and tools as a building blocks; EDM4hep --- common datamodel intended for all stages of the event lifecycle (from simulation, through reconstruction, up to the analysis); DD4hep --- detector description able to compartmentalize individual sub-detectors allowing Plug-and-Play approach; and Spack --- software distribution solution providing multiple versions and/or multiple configurations of a package.
We demonstrate the use of an autoencoder style generative neural network (NN) architecture on problems in the estimation and control of accelerators. Using HPSim, a high-performance particle tracking code, we generate datasets and train a NN to map from accelerator tuning parameters and the initial condition to measurements of interest, like phase space projections and beam loss, as well as reproducing the initial condition itself. We assume that certain outputs of the NN, like beam loss, can be measured from a real accelerator system, which can be compared with the NN prediction to generate an error signal. This error signal can be used to estimate quantities like the initial condition and phase space projections --- even after training when these quantities change over time and cannot be measured. We also show how this method can be used to perform control actions to tune the beam.
IDEA detector concept foresees a muon detection system that would be realized using the μRWELL technology. Each station will consist of a large mosaic of 50 × 50 cm2 μRWELL detectors.
The objectives include simulating and optimizing the IDEA muon detector design within Key4hep simulation toolkit, evaluating its performance and estimating its physics reach for highly displaced charged particle signatures.
The Triple Track Trigger (TTT) concept is proposed for the FCC-hh detector to exploit the full potential of the unprecedented energy ($\sqrt{s} = 100\,\mathrm{TeV}$) and high luminosity ($30\times 10^{-34}\,\mathrm{cm^{-2}s^{-1}}$) proton-proton (pp) collisions at FCC-hh. The primary objective of the TTT is to trigger physics at the electroweak scale in real time by significantly suppressing signals from the low energetic pp collisions at a pileup rate of $\sim\!\mathcal{O}(1000)$, assuming $25\,\mathrm{ns}$ bunch crossing.
The TTT concept is based on a highly scalable state-of-the-art monolithic pixel sensor technology comprising three closely stacked and highly granular pixel barrel layers at large radii ($\sim\!\!1\,\mathrm{m}$). An extension of the TTT to the endcap region increases the geometrical acceptance to a pseudorapidity of 2.5. A simple and fast algorithm, which can be implemented in hardware processors at the first trigger level, enables online reconstruction of all TTT tracks at $40\,\mathrm{MHz}$. Additionally, TTT enables the reconstruction of pileup-suppressed track-jets to trigger physics signals of interest by reconstructing the primary collision vertex with high efficiency.
This presentation focuses on a case study demonstrating the ability of the TTT to trigger the rare physics process of $\mathrm{HH} \rightarrow 4b$ [arXiv:2401.16046]. Based on a Geant4 simulation of the FCC-hh detector including the TTT, both the tracking and the trigger performances have been studied. A comparison of the TTT with a calorimeter trigger, illustrates TTT's superiority to select $\mathrm{HH} \rightarrow 4b$ events with an order of magnitude lower trigger threshold. Due to the lower trigger threshold, a substantial gain in sensitivity for measuring the Higgs self-coupling is expected. Last but not the least, a potential hardware implementation of the concept is outlined.
Dual readout crystal calorimetry allows state-of-the-art electromagnetic resolution while preserving excellent jet energy resolution. We report here updated results from the CalVision and MaxiCC collaborations, including new results from an electron test beam at DESY. We also present new results on full simulations of the calorimeter incorporated into the IDEA detector
The IDEA detector is one of the concepts under research for the Future Circular Collider (FCC). For its innermost part, the Vertex Detector, which would occupy a cylindrical volume of 50 mm radius and 550 mm lenght, a power dissipation of about 120 W is foreseen. For the removal of this heat, a cooling system based on forced air convection is under development. Such a technical solution would minimize the quantity of material located in the tracking volume, concentrating all the services only in the two endcaps. The sensitive volume would therefore be occupied only by sensors and related support structures, which would also act as cooling fins to maximize convective heat exchange. In this scenario, Computational Fluid Dynamics (CFD) and, more widely, Finite Volume Simulations, can offer a useful tool to evaluate the feasibility of this solution and to guide the designers in the optimization of the thermal performance. An example of a calculation model developed with the Ansys simulation suite will be given, showing how thermal performance varies by adopting different construction choices. Furthermore, starting from this model and the structural analysis if the system, the evaluation of the vibrational effect due to the interaction between the fluid and the lightweight structure is implemented.
In this poster is presented a study on the structural optimization of the support structure for the interaction region (IR) of the Future Circular Collider (FCC). The aim is to optimize the structure to reduce the mass, maintaining the stiffness needed. Finite element analysis (FEA) is used to develop a detailed numerical model considering complex geometries, material properties, and loading conditions. The study seeks to identify design improvements using optimization algorithms, such as SIMP, Generative Design and Lattice approach, to ensure the respect of requirements of the FCC IR support structure during operation.
We present the material budget for the latest engineered design of the interaction region (IR) of the Future Circular Collider (FCC).
In order for the LumiCal to reach the required absolute precision, it is necessary to use high radiation length (X0) material for the beam pipe elements in front of this detector.
We compare the material budget in the LumiCal acceptance for two versions of the IR beam pipe, mainly differing for the cooling manifolds material (copper and AlBeMet162). We also show the energy deposit in the LumiCal induced by secondary showers coming from the beam pipe material.
The design of the next generation of colliders demands a renewed, high-performance, integrated set of simulation codes. We present the Beam, pLasma & Accelerator Simulation Toolkit (BLAST), which includes legacy accelerator codes such as Impact-T, Impact-Z, Warp and Posinst, as well as a renewed generation of accelerator codes such as ImpactX, WarpX and HiPACE++. The new codes, born out of the US DOE Exascale Computing Project (ECP), all share a common foundation based on the AMReX library that gives native support for mesh refinement and high performance on both CPU-based and GPU-based computer architectures. The integrated set also includes python-driven workflows for efficient parametric optimization and coupling with machine learning frameworks. We will present the latest of the toolkit and new codes, with discussion on their applications to start-to-end modeling of colliders from the source to the interaction point including beam-beam crossing effects.
The charge imbalance between colliding bunches in the FCC-ee ring must be less than 3-5% in order to avoid the beamstrahlung-induced flip-flop instability [1]. The charge of the colliding bunches is leveled through top-up injection, but this is a slow process. Laser Compton back scattering (CBS) has been proposed as a mechanism to quickly level the charge of colliding bunches between top-ups [2]. This scheme has been shown to be effective through simulations of the Compton interaction and turn-by-turn modeling of the FCC [3]. In this work, we seek opportunities to improve performance and reliability of the CBS system. We explore strategies for reducing the required energy in the laser pulse by reducing the pulse spot size. To prevent radiation damage to the laser optics, we introduce a finite angle of incidence between the laser and e+/e- beams. We study the interplay between angle of incidence and laser pulse length in this scenario. We investigate novel concepts, such as using short pulse lasers for quenched photon emission in the strong-field regime [4,5]. Finally, we discuss opportunities for experimental tests using the E320 infrastructure at FACET-II.
[1] D. Shatilov, “BEAM-BEAM EFFECTS AT HIGH ENERGY e+e– COLLIDERS,” TUYBA02, eeFACT2018, Hong Kong, China
[2] F. Zimmerman, T. Raubenheimer, “CONTROLLING e+/e− CIRCULAR COLLIDER BUNCH INTENSITY BY LASER COMPTON SCATTERING,” WEPOST010, IPAC2022, Bangkok, Thailand.
[3] I. Drebot et al., “OPTIMIZING THE BEAM INTENSITY CONTROL BY COMPTON
BACK-SCATTERING IN e+/e- FUTURE CIRCULAR COLLIDER,” MOPA074, IPAC2023, Venice, Italy.
[4] C. N. Harvey et al. "Quantum Quenching of Radiation Losses in Short Laser Pulses” Phys. Rev. Lett. 118, 105004 (2017)
[5] M. Tamburini and S. Meuren, "Efficient high-energy photon production in the supercritical QED regime” Phys. Rev. D 104, L091903 (2021)
We propose a concept for a e+ source based on high energy e- beams incident on conical converter targets, in pursuit of its implementation in future lepton colliders such as FCC-ee. Two conical target solutions were optimized for a state-of-the-art capture system based on a high-temperature superconducting solenoid, allowing for a full target immersion in a 12.7 T peak field. According to simulation studies, conical targets would increase by up to 70% the e+ yield accepted by the FCC-ee damping ring, including the detrimental impact of their mechanical interface and cooling pipes. A thermo-mechanical study of 2 conical targets and their supports is also presented, using the baseline parameters of the FCC-ee injector linac, as well as a mechanical integration concept for P$^3$, the future FCC-ee e+ source test facility.
The P$^3$ experiment is the positron source test facility for FCC-ee, which is presently under construction at the Paul Scherrer Institute in Switzerland. The proposed diagnostics setup will detect the charge, longitudinal profile, and energy spectrum of multispecies electron-positron beams in the nano-Coulomb and multi-MeV range. Additionally, the diagnostics must work under extremely challenging emittance and energy spread conditions. Three instrumentation setups are essential to achieve this: non-invasive longitudinal bunch profile monitors based on broadband pick-ups, Faraday cups, and energy-spectroscopic setups based on scintillator screens and fibers. These studies are based on computer simulations and experimental measurements carried out at the CERN's CLEAR facility.
The FCCee complex will produce and transport the lepton beams to the collider ring. From the damping ring to the top-up injection in the collider ring, beam transfer systems are required to ensure beam injection and extraction. Each system has specific requirements, determined by the beam energy, required deflection, available space and so on. This contribution presents the concepts for injection and extraction systems across all those machines. A focus on the collider technical straight section of point B highlights particular challenges associated with the integration of booster and collider systems.
During operation, the Future Circular electron-positron Collider (FCC-ee) will be subject to vibrations from mechanical sources and ground motion, resulting in errors with respect to the closed orbit. To achieve physics performance, luminosity and beam lifetime must be kept to design specifications. To correct for errors at the interaction points (IPs), a fast feedback system is required. We present the tolerances for the allowable beam offsets at the IPs and propose a fast feedback system to address these errors, with the methods of detecting and correcting errors discussed.
The Future Circular electron-positron Collider (FCC-ee) is a proposed accelerator with a 91 kilometre circumference that should serve as a Higgs and electroweak factory, with unprecedented luminosity. Unavoidable misalignments and field errors will generate optics errors at the interaction point (IP), whose effect will be amplified by the beam-beam collisions, which will make it challenging for the collider to reach its intended luminosity goals. Hence, there is a need for correction tools that will enable the precise correction of the optics at the IP, such as linear coupling parameters and spurious dispersion. This will be essential both for FCC-ee commissioning and during routine operation. This poster describes the construction, simulated effectiveness, and constraints of IP tuning tools and the pyAT optics tuning of FCC-ee lattice.
The detectors to be operating at the Future Circular electron-positron collider (FCC-ee) must fulfill demanding requirements on the high precision measurements. Key requirements for the detector include excellent energy and angular resolution as well as excellent particle identification capabilities. The ALLEGRO detector is a general-purpose detector concept well suited for the FCC-ee. The individual parts of the detector are introduced. The calorimeter system consists of high granular noble-liquid calorimeter and hadronic calorimeter with scintillating tiles and readout of the wavelength shifting fibers. Preliminary results from performance studies using simulated beams of electrons and pions are presented. In addition to these design-focused analyses, we briefly introduce our inquiries into the potential use of machine learning approaches for particle identification and detector calibration.
FCC-ee luminosity optimization relies on measuring realistic signals from Bhabha scattering, beamstrahlung, and radiative Bhabha photons. Initial assessments of beamstrahlung signals examine the change in luminosity and beamstrahlung power in response to waist shifts and vertical dispersion at the collision point. These ongoing studies aim to extract IP-aberration-related signals from the energy spectrum, angular distribution, and power of beamstrahlung photons. Furthermore, the study is to be extended to include signals from the luminometer and vertex detector, potentially integrating all of them into a machine-learning-based approach for luminosity tuning and optimization.
The accelerator circumference will remain an unchangeable parameter throughout the entire life of the FCC program. A cautious choice is therefore essential to cover all present and future requirements in terms of beam transfer schemes or bunch spacing and length. The exact circumference becomes particularly important for the FCC-hh, when hadron beams will be supplied by a high-energy booster synchrotron either in the SPS or the LHC tunnel. The numerator and denominator in the rational circumference ratio between the FCC and its injector define the fundamental periodicity of possible beam transfers. The ratio of FCC and LHC for the present baseline circumference is extremely close, but not exactly 17/5. Moving it to precisely that value by shorting the tunnel by 18 m would allow hadron injections to take place every five revolutions, opening the door to, for example, RF manipulations to control the bunch length and alternative beam transfer schemes. This contribution summarizes the impact of the proposed fine tuning of the FCC circumference on RF frequencies, as well as its benefits for more flexibility at beam transfer.
High-energy and high-luminosity collision experiments on the future collider demand higher radiation resistance and time resolution detectors due to events pile-up. Silicon Low-gain avalanche detectors (LGADs) with excellent time resolution have been identified for use in collider experiments, such as ATLAS and CMS experiments. However, due to the inherent properties of silicon material, the operating voltage and temperature requirements for irradiated Si LGADs are even more demanding. Especially in environments with irradiation fluences exceeding $10^{16}~ n_{eq}/cm^{2}$ and under general detector operating conditions, there is a need to explore new solutions.
In comparison to silicon, silicon carbide (SiC) offers lower intrinsic carrier concentration, faster carrier saturation drift velocity, higher breakdown electric field, and greater theoretical radiation resistance. This makes it a promising candidate for applications in collider experiments.
In recent years, with the increasing demand for commercial silicon carbide power devices, related silicon carbide processing technologies have rapidly advanced. This has made it possible to fabricate multi-layer epitaxial structures of silicon carbide devices, such as SiC LGAD. However, the fabrication of SiC LGAD also imposes additional requirements on the processing technology, such as ultra-low-doped silicon carbide epitaxial layers, precise control of epitaxial layer doping concentration and thickness, and termination etching. We will report on the latest developments in SiC LGAD conducted by Lawrence Berkeley National Laboratory(LBNL) and North Carolina State University (NCSU).