FCC Week 2021
Monday, 28 June 2021 - Friday, 2 July 2021
Book of Abstracts ii Contents
Layout and optics for a collimation insertion in FCC-ee ...... 1
Human capital formation at the FCC ...... 1
Combined effect of impedance and beam-beam ...... 1
A Robotic System for Remote Interventions in the FCC Complex ...... 1
SRF characterization of multilayers ...... 2
Status of the high-energy booster ...... 2
Mechanical design of the MDI ...... 3
Transport and logistics for FCC ...... 3
Two Stage High Efficiency Klystron for FCC-ee ...... 4
Overview of the EIC Beam instrumentation and synergies with FCC ...... 4
Electron cloud simulations for arc quadrupoles ...... 4
Electron Cloud Simulations for the FCC-ee ...... 5
Design of the FCC-ee collider magnets ...... 5
Collective effects for single-beam in FCC-ee and Impedance database ...... 6
Physics at FCC ...... 6
RF Characterization Techniques of 1.3 GHz Cavities ...... 6
Mining the Future contest performance and output ...... 7
Prospects of positron and positronium physics with a highly intense low energy positron source ...... 7
Cooling and ventilation concepts for the FCC ...... 8
HTS Coated Conductors for beam impedance reduction in the FCC-hh ...... 8
FCC-ee collective effects: introduction and overview(including Full Energy Booster) . . 9
Status and plans for optics corrections and emittance performance ...... 9
Status and plans for FCC-hh optics studies ...... 10
iii First steps towards a collaborative software framework for the FCC-ee simulations: Amul- ticode comparison ...... 10
Machine Detector Interface Alignment System Update ...... 10
Prototyping the Nb coating of the copper Wide Open Waveguide Crab Cavity (WOWCC) for FCC-hh ...... 11
Key Vacuum Surface Parameters for FCC-ee Operation ...... 11
Overview, plan and open questions ...... 12
SuperKEKB collimation system ...... 12
Powering strategy - focus on main dipole magnets ...... 12
Arc vacuum system and synchrotron radiation ...... 12
Filling schemes through injector chain ...... 13
Roadmap for the FCC Feasibility Study ...... 13
The status of global FCC collaboration ...... 13
Synchrotron Radiation studies for the FCC-ee arc with FLUKA ...... 14
Status of Electricity and energy management work package ...... 14
Technical Infrastructure operations today and in the future ...... 15
Mining the Future - status and progress ...... 15
Progress in the design of the linacs and electron sources for the FCC-ee injector complex 16
The SWELL cavity development ...... 16
Introduction on the socio-economic impact assessment model ...... 16
Regional and territorial benefit identification: approach and method ...... 17
Spatial impact analysis of Large Research Infrastructures: A case study on SRF cavities . 17
Status of bellows and flanges impedance studies ...... 17
Geodetic studies for FCC ...... 18
What software for ’Higgs and Electroweak Factories’? ...... 18
Bc -> tau nu at FCC-ee ...... 18
ARC: a solution for particle identification at FCC-ee ...... 19
Long-lived particles at FCC ...... 19
Status and plans for FCC-hh collimation ...... 20
Overview and layout ...... 20
iv Performance of a Crystal + Dual readout Calorimeter system at FCC-ee ...... 20
FCC-ee & hh cryogenic system conceptual design, status & perspectives ...... 21
FCC-ee booster as ultimate storage ring photon source ...... 21
Parameters - update and plan ...... 22
Robust Modelling of FCC-ee with Analytical Equations and Simulations ...... 22
Hydroforming Elliptical SRF Cavities : Studies on 1.3 GHz and Beyond ...... 22
Bridging research & industry: Creating value from FCC‘s technologies for the general pub- lic ...... 23
Training the professionals of the future ...... 23
WP7 results and prospects ...... 23
FCC.eh: Update and ERLs ...... 23
LHeC Racetrack as Injector to FCC-ee ...... 24
Interaction Region Design Optimization ...... 24
Probing Spacetime with Colliders ...... 24
FCC-ee Aperture and Collimation ...... 24
Experience at SuperKEKB ...... 25
Science case for high-energy photons ...... 25
Optics and layout - update and plan ...... 25
Superconducting Thin Films Studies at CERN ...... 26
Cavity Engineering & Fabrication at CERN ...... 26
Placement: Report from the review and next steps ...... 27
Beam-beam background and beamstrahlung studies at FCC-ee ...... 27
Advanced Fabrication and Vacuum Compatibility of Tl-1223 Superconducting Thin Films for the Future Circular Collider (FCC-hh) Beam Screen ...... 27
From vertex to wrapper: the IDEA tracklng system for FCC-ee ...... 28
FCC-ee positron source ...... 29
The FCC-PED Informal Forum of National Contacts ...... 29
Beam-cavity interaction challenges for the FCC-ee ...... 29
ECFA roadmap for Detector R&D and plans for ECFA workshops on an e+e- Higgs/EW/Top factory ...... 30
Global Plans for High Field Magnet R&D ...... 30
v FCCAnalysis: tools and algorithms for analysis ...... 30
Communicating the FCC feasibility study ...... 30
What’s new at Overleaf in 2021? ...... 31
Requirements on FCC-ee from the physics programme ...... 31
Status of implementation of high-priority Accelerator R&D initiatives ...... 32
Physics, Experiments and Detectors pillar: Structure and Objectives ...... 32
Targets, milestones and progress of Physics Performance ...... 32
News on the Q1 magnet prototype’ ...... 32
Baseline & Cavity options for FCC-ee ...... 33
Update on Snowmass process & US perspectives incl. EIC ...... 33
Higgs mass and model-independent cross-section studies from the recoil mass ...... 33
The turnkey software stack Key4hep: status and plans ...... 33
Jet Flavour tagging at the FCC-ee ...... 34
FCCSW: status and (users) workflows ...... 34
Probing heavy new physics systematically at FCC ...... 34
Excavation materials management plan: progress and ongoing work ...... 34
Host states processes: Update and next steps ...... 35
From collaboration to submission ...... 35
Round table discussion ...... 35
Modifications of injection and beam dump systems for new collider layout ...... 35
FCCIS scientific meetings and publication status ...... 35
FCC Communication Strategy ...... 35
FCC-ee upgrade to muon collider ...... 36
Overview of Multilayer Developments at Jlab ...... 36
Accelerator summary ...... 36
Technologies summary ...... 36
Summary of FCCIS work packages 3, 4 and 5 ...... 37
Technical Infrastructure and Civil Engineering summary ...... 37
Physics, Experiments and Detectors summary ...... 37
Closing remarks ...... 37
vi Detector challenges, towards detector concepts at FCC-ee ...... 37
Overview of the EIC RF system and synergies with FCC-ee ...... 38
Status of heavy neutrino searches at ep colliders ...... 38
Recent developments on scintillator materials for calorimetry ...... 38
Integration of the FCC ...... 39
Turbocompressor test facility operating with Nelium mixtures and heat transfer effects . 39
Safety for the FCC Feasibility Study ...... 39
Electro-hydraulic forming of SRF cavities: Effect of strain rate on niobium single crystals 40
Top up injection - Status and next steps ...... 40
FPC challenges and perspectives for FCC-ee ...... 41
LHeC and FCC-eh detector status ...... 41
3D geological modelling and subsurface uncertainties quantification to guide the optimal FCC placement ...... 41
Design Studies and HiRadMat test for the FCC-ee Beam Dump System ...... 42
Opening, CERN vision and plans until 2025 ...... 42
Civil Engineering assessment of placement scenarios by ILF Consulting ...... 42
SRF summary ...... 42
ERL-based e+e- collider ...... 43
Civil Engineering Status and Plans ...... 43
Some experiences with the vacuum system in SuperKEKB ...... 43
Longitudinal bunch-by-bunch profile measurements at KARA based on EO sampling & developments for FCC ...... 44
Status and scope of the FCC Innovation Study ...... 44
How the Higgs boson opens a new window on fundamental physics? ...... 45
Potential of a future circular collider to address the dark sector of the universe ...... 45
vii viii FCC Week 2021 / Book of Abstracts
FCC-ee accelerators / 1
Layout and optics for a collimation insertion in FCC-ee
Author: Michael Hofer1 Co-authors: Andrey Abramov 1; Roderik Bruce 1; Katsunobu Oide ; Frank Zimmermann 1
1 CERN
Corresponding Author: [email protected]
The design parameters of the FCC-ee foresee operation with a total stored beam energy ofabout 20MJ, exceeding those of previous lepton colliders by almost two orders of magnitude. Given the inherent damage potential, a halo collimation system is studied to protect the machine hardware, in particular superconducting equipment such as the final focus quadrupoles, from sudden beam loss. In this talk, a preliminary layout and optics for a collimation insertion are presented, taking into consideration constraints from other systems such as the polarimeter.
FCCIS WP4 (Impact & Sustainability) / 2
Human capital formation at the FCC
Author: Francesco GiffoniNone Corresponding Author: [email protected]
FCC will have an impact on the career development of students and young researchers who spend a research period at CERN. The presentation presents estimates on the number of people whowill benefit from human capital formation during the FCC lifetime, as well as preliminary results ofthe expected benefits for their salary and careers.
FCC-ee accelerators / 3
Combined effect of impedance and beam-beam
Author: Yuan Zhang1 Co-authors: Emanuela Carideo 2; Mikhail Zobov ; Mauro Migliorati 3
1 IHEP-CAS 2 Sapienza Universita e INFN, Roma I (IT) 3 University of Rome ”LA SAPIENZA”
Corresponding Author: [email protected]
With large Piwinski angle collision, both luminosity and beam-beam tune shifts depend on the bunch length. The longitudinal beam dynamics also plays an essential role for several new effects, such as beamstrahlung, coherent X-Z instability and 3D flip-flop. The combined effect of longitudinal impedance and beam-beam interaction should be taken into account for the collider luminosity op- timization. The impact on the coherent X-Z instability is focused. Simulation results are shownfor different schemes: CDR, higher harmonic cavity, large momentum compaction and4IPs.
Technology R&D / 5
Page 1 FCC Week 2021 / Book of Abstracts
A Robotic System for Remote Interventions in the FCC Complex
Author: Hannes Gamper1
Co-authors: Mario Di Castro 2; Hubert Gattringer 1; Andreas Mueller 1
1 Johannes Kepler University, Linz 2 CERN
Corresponding Author: [email protected]
The perception, cognition and control of robotic systems was advancing rapidly in the last decades and is even speeding up, benefiting from increasing computation power and technologies like arti- ficial intelligence. These developments enabled robots to handle more complex tasks with ahigher degree of automation. Extrapolating the state of robotic intelligence by about two decades, the time when the FCC Robot would operate in the FCC tunnels, such systems will be able to handle most of the planned interventions that are currently, mainly conducted manually and many of the un- planned or emergency situations. Additionally, most of the manually performed interventions in the LHC complex can not be applied to the three times longer FCC tunnel, without either increasing efforts in workforce and money or accepting longer machine down times. Thus, a robotic system will decrease machine down time, reduce the radiation exposure of workers and will locate, guide and possibly rescue workers in case of emergencies. This work presents a robust robotic system for remote and automated interventions over thefull life cycle of the FCC complex. First, a Remote Maintenance Code of Practice, which is based on the experience of over 1000 robotic operations at CERN will be presented. The code of practice provides guidelines for standardized, robotic friendly designs which are key to facilitate most efficient inter- ventions. Furthermore, a survey listing the most important robotic interventions and the derived requirements and restrictions will be discussed. Some ongoing work concerning the integration of the robotic system in the cross section of the FCC tunnel and related logistics will be shown. Finally, results from simulations, design optimizations and the corresponding future prototype for proof of concept studies will be presented.
SRF / 6
SRF characterization of multilayers
Author: Sebastian Keckert1
1 Helmholtz-Zentrum Berlin
Corresponding Author: [email protected]
Superconducting radio frequency (SRF) cavities with performance beyond the fundamental limits of bulk niobium require coating technologies. Multilayer systems with alternating thin films of superconducting and insulating material promise to boost the performance in terms of maximum accelerating gradient and surface resistance. Futhermore, the insulating layer prevents full pene- tration of vortices that would otherwise lead to an unmanageable level of RF dissipation. Using the Quadrupole Resonator (QPR) at Helmholtz-Zentrum Berlin, several series of multilayer samples have been characterized in a wide parameter space of temperature, RF field and frequency. Impor- tant aspects of the theoretical models could be verfied experimentally, however, unexpected features such as a non-monotonic temperature dependence of the surface resistance and early quench limits have been observed. The measurements indicate that further parameters, especially concerning the insulating layer, have to be taken into account.
FCC-ee accelerators / 7
Page 2 FCC Week 2021 / Book of Abstracts
Status of the high-energy booster
Authors: Antoine Chance1; Barbara Dalena2; Bastian HaererNone; Herve Josselin De Grandsaignes D’Hauterives3
1 CEA Irfu 2 CEA-Irfu & Université Paris-Saclay (FR) 3 Université Paris-Saclay (FR)
Corresponding Author: [email protected]
The high-energy booster is the last part of the accelerator complex before the FCC-ee collider. The booster has to handle several challenges common to the FCC-ee collider like fitting the100-km- long tunnel, reaching low equilibrium emittances, or longitudinal stability because of a very small momentum compaction. Nevertheless, the booster has also specific challenges. At injection, magnetic field in the dipoles is very low; which brings some issues of reproducibility of the field and large random errors. More- over, the damping time is longer and the lattice needs some undulators for instance to speed upthe damping time by 2 orders of magnitude. At larger energies, the beam energy varies along the arc because of synchrotron radiation. Contrary to the collider, it is not possible to use tapering, which makes orbit correction an issue while acceleration. We show the status and performances of the lattice, including a new tool to generate the optics in agreement with the tunnel geometry.
FCC-ee accelerators / 8
Mechanical design of the MDI
Author: Francesco FransesiniNone
Co-authors: Luigi Pellegrino ; Manuela Boscolo 1
1 INFN e Laboratori Nazionali di Frascati (IT)
Corresponding Author: [email protected]
The presentation concerns: the preliminary assembly of the MDI, including vacuum chamber, quadrupoles and solenoids; a parametric mechanical analysis of the vacuum chamber and the preliminary study of heat removal in the central beam pipe.
The mechanical study examines the structural behaviour of the chamber at many thickness values, using FEA techniques. The preliminary heat transfer study is intended to determine the feasibility of using paraffintore- move the heat load in the central part of the vacuum chamber, considering the annular gap available and the allowable pressure head.
Technical infrastuctures / 9
Transport and logistics for FCC
Author: Cristiana Colloca1
1 CERN
Page 3 FCC Week 2021 / Book of Abstracts
Corresponding Author: [email protected]
For material and people, logistics, transport and handling are of great importance in the construc- tion, assembly and operation of the FCC. The presentation will focus on transport scenarios, design concept for special vehicles for theunder- ground transportation and handling, design concept for bridge cranes and lifts as well as assembly, testing and storage facilities organization and supply strategies.
SRF / 10
Two Stage High Efficiency Klystron for FCC-ee
Authors: Jinchi Cai1; Igor Syratchev2; Graeme Campbell Burt1
1 Lancaster University (GB) 2 CERN
Corresponding Author: [email protected]
The innovative concept of two-stage multi-beam Klystron has been previously investigated andstud- ied in a 1GHz 20MW Klystron for CLIC. This technology utilizes low voltage electron beam inits first stage to compress the tube length and DC post acceleration in the 2nd stage to ensureultra- high efficiency. It is very practical for the compact design at low frequency (UHF and L-band), high power (Multi Megawatt), high efficiency (>80%) Klystrons, hence the same concept was adopted for the development of a 0.4GHz 1.2MW Klystron for FCCee. The beam-wave interaction optimization of this device has been performed in an updated version of KlyC and innovative RF parts such as a RF rejecter structure for the post-accelerating gap and photonic array-inspired rods for the output cavity will also be demonstrated in this report. Further exploration of the new technology, and prac- tical beam optics design has been preliminarily done in a new 2D code CGUN and further complex 3D optimization is ongoing. Overall, the Klystron is expected to deliver a maximum power of over 1.2MW with 80% efficiency.
Technology R&D / 11
Overview of the EIC Beam instrumentation and synergies with FCC
Author: DAVID GASSNER1
1 BNL
Corresponding Author: [email protected]
The electron-ion collider (EIC) to be constructed at Brookhaven National Laboratory is presently in the conceptual design phase of development. This facility will be based on the existing RHIC complex. There will be a new electron gun, linac and rapid cycling synchrotron feeding the 5-18 GeVstorage ring to provide polarized electrons for collision with hadrons. The existing RHIC hadron rings will be reconfigured into one combination acceleration and storage ring to provide 40–275 GeVhadrons, this includes polarized protons. A strong hadron cooling facility is included in the baseline, the cooling is realized by co-propagating 120 mA, 150 MeV micro-bunched electrons with the hadron beam. A brief overview of the proposed beam instrumentation will be presented along with potential collaborations with the FCC.
FCC-ee accelerators / 12
Page 4 FCC Week 2021 / Book of Abstracts
Electron cloud simulations for arc quadrupoles
Authors: Damian Ismael Ayim Canche1; Georfrey Humberto Israel Maury Cuna2; Karla Beatriz Cantun Avila1
1 Universidad Autónoma de Yucatán 2 Universidad de Guanajuato
Corresponding Author: [email protected]
The electron cloud is one of the critical issues to be addressed due to its capability to affect theFCC-ee accelerator performance and degrade beam quality, in particular, for the arcs of the machine. In this work, we report the first part of a series of studies on electron cloud build-up for the arc quadrupole sections. Variations mainly on beam energies, beam pipe radii, and secondary electron emission yields were explored. In addition, we found a significant reduction in electron central density when winglets are implemented as part of the beam pipe chamber.
FCC-ee accelerators / 13
Electron Cloud Simulations for the FCC-ee
Authors: Fatih Yaman1; Frank Zimmermann2; Mikhail ZobovNone; Dmitry Shatilov3; Roberto Kersevan2; Kazuhito Ohmi4; Salim Ogur5; Giovanni Iadarola2
1 Izmir Institute of Technology (IYTE) 2 CERN 3 Budker Institute of Nuclear Physics (RU) 4 KEK 5 Centre national de la recherche scientifique
Corresponding Author: [email protected]
In high-energy particle accelerators, electron clouds may occur due to high synchrotron radiation- related photoemissions, residual gas ionization, and secondary emissions during positively charged beam circulations in the vacuum chambers. The electron cloud formation could cause beam losses, trajectory changes, and wakefields. This study presents electron cloud build-up investigations for different scenarios in the scope of FCC-ee damping and collider ring machines and beamparame- ters. We employ two-dimensional electrostatic particle-in-cell simulations where the effects of space charge, secondary, and photoelectrons are included. Furman-Pivi and ECLOUD secondary emission yield models are applied for the numerical experiments. The electron density at the center ofthe beam pipe for various bunch spacings, secondary emission yield, and photoemission yield parame- ters are studied. We obtained reference electron cloud level and neutralization densities.
Technology R&D / 14
Design of the FCC-ee collider magnets
Author: Jeremie Bauche1
1 CERN
Corresponding Author: [email protected]
The presentation will recall the designs proposed in the CDR and address options to accommodate additional features like the field tapering needed to mitigate the energy saw-tooth effect.
Page 5 FCC Week 2021 / Book of Abstracts
FCC-ee accelerators / 15
Collective effects for single-beam in FCC-ee and Impedance database
Author: Emanuela Carideo1 Co-authors: Mauro Migliorati 2; Mikhail Zobov 3; Frank Zimmermann 4
1 Sapienza Universita e INFN, Roma I (IT) 2 University of Rome “La Sapienza” and INFN, Rome, Italy 3 LNF INFN, Rome, Italy 4 CERN, Geneva, Switzerland
Corresponding Author: [email protected]
Improving the accuracy of the impedance model of an accelerator is important for keeping beam instabilities and power loss under control. Here, by means of the PyHEADTAIL tracking code, we first review the longitudinal microwave instability threshold for FCC-ee by taking into accountthe longitudinal impedance model evaluated so far. Moreover, we present the results of beam dynamics simulations, including both the longitudinal and transverse wakefields due to the resistive wall, in order to evaluate the influence of the bunch length on the transverse mode coupling instability. The results of the transverse beam dynamics are also compared with the Vlasov solver DELPHI.
Physics, Experiments & Detectors / 16
Physics at FCC
Author: Matthew Reece1
1 Harvard University
Corresponding Author: [email protected]
In this talk, I will give a broad overview of the physics case for the FCC. I will review the puzzles of the Standard Model and opportunities to go beyond it, and discuss how the FCC plans fit in this context. FCC-ee can provide a major boost to the precision study of the Standard Model and electroweak symmetry breaking, while also offering opportunities to search for new physics. FCC-hh will provide a new energy frontier with potential direct access to new physics, as well as opportunities for further precision measurements, such as the Higgs self-coupling. The combination of the two is a logical path forward that can define the agenda of particle physics well into the 21st century.
SRF / 17
RF Characterization Techniques of 1.3 GHz Cavities
Authors: Antonio Bianchi1; Lorena Vega Cid1; Pablo Vidal Garcia2; Walter Venturini Delsolaro1
1 CERN 2 Centro de Investigaciones Energéti cas Medioambientales y Tecno
Corresponding Author: [email protected]
Among the bases that substantiate the feasibility of the FCC, the RF characterization of scaled ver- sions of accelerating cavities becomes one of the major milestones within the project timeline. In
Page 6 FCC Week 2021 / Book of Abstracts
particular, niobium thin film cavity deposition is regarded as the main alternative to the bulk(for example, this is the technology used in the HIE-ISOLDE QWRs at CERN), leveraging the heat trans- fer efficiency of copper as substrate, among many other advantages of this technology. Keeping that in mind, the R&D procedure for the coating optimization may be summarized as follows: (i) as first step, the evaluation of the sputtered niobium on copper flat samples is carried outbyusinga quadrupole resonator (QPR). The QPR allows for a controlled test of the thermally isolated sample exposed to RF fields. This test is based on a precise calorimetric compensation applied to a relatively simple geometry so that the possible uncertainties during both the sample manufacturing and test- ing are greatly reduced; (ii) then, the recipe used for the sample preparation is repeated to produce the coated cavities; and (iii) in order to push the cavity performance and overcome the mid- and high-field Q-slope, the current strategy attempts to optimize the substrate for the film deposition. In this sense, two different prototypes of seamless substrates: one made of copper electroformed ona mandrel and another one machined from the bulk; are successively tested at the cryolab to master the preparation technique. In parallel, a thermal mapping system for coated cavities, based on con- tact thermometry, is under development to pinpoint the mechanisms responsible of performance degradation.
FCCIS WP5 (Leverage & Engage) / 18
Mining the Future contest performance and output
Authors: Katrien WitpasNone; Camille DifferdangeNone
Corresponding Author: [email protected]
This presentation will showcase the Mining the Future competition and communications campaign. The FCC study wants to couple scientific discovery with environmental sustainability. Buildinga Future Circular Collider and the infrastructure related to it would generate about 9 million cubic metres of excavated materials, mainly molasse. The Study wants to divert these materials from landfills and put them to good use. That is why the FCC collaboration, CERN and Montanuniversität Leoben, with the support ofthe EU-funded H2020 FCCIS project, have launched the Mining the Future competition. This competi- tion hopes to identify sustainable reuse solutions for materials excavated during the construction of a next-gen collider. It also wants to draw a roadmap for wider applications beyond this specific project.
FCC-ee accelerators / 19
Prospects of positron and positronium physics with a highly in- tense low energy positron source
Authors: Benjamin Rienacker1; Ruggero Caravita2
1 Physics Department, CERN 2 Universita degli Studi di Trento and INFN (IT)
Corresponding Authors: [email protected], [email protected]
We report on the possible use cases for an highly intense low energy positron source in the light of the FFC-ee project. Slow positrons can be used to create the purely leptonic hydrogen-like positronium (Ps) atom, the bound state of an electron and a positron. Since it does not contain a hadronic nucleus, it is a privileged system to research bound-state QED. Notably, theoretical results regarding Ps exceed the current experimental precision, which is why new fundamental precision experiments on Ps are very interesting. But also the possibility of Bose-Einstein condensates with Ps becomes more likely with a more intense positron source, and ultimately the first steps towards a gamma-ray laser may
Page 7 FCC Week 2021 / Book of Abstracts
be investigated. Ps is a symmetric matter-antimatter system which enables direct tests onCPT- symmetry and possibly also on the WEP by means of free-fall experiments in a well controlled environment. As a more user-oriented case, slow positrons can be used as non-destructive nanoprobes for defects in all types of materials, and an intense source might develop towards an useful tool for industry to test samples with high throughput.
Technical infrastuctures / 20
Cooling and ventilation concepts for the FCC
Author: Guillermo Peon1 Co-authors: Ingo Ruehl 1; Michele Battistin 1
1 CERN
Corresponding Authors: [email protected], [email protected], [email protected]
The cooling and ventilation systems are an integral part of the functioning of any accelerator buteven more complex and challenging for the FCC due to the huge distances between sites and shafts. The presentation will outline the proposed cooling and ventilation concepts and the challenges in- volved. Furthermore it will give an outlook of the phase 2 studies that will be conducted with external experts and consultants. The phase 2 studies will also include an in-depth study of the environmental impact intermsof energy- and water consumption, heat recovery, waste water and air exhaust.
Technology R&D / 21
HTS Coated Conductors for beam impedance reduction in the FCC-hh
Authors: Joffre Gutierrez Royo1; Artur RomanovNone; Guilherme Telles2; Neil Lamas3; Patrick KrkoticNone; Juan Manuel O’Callaghan CastellaNone; Xavier Granados2; Elisa Garcia-Tabares Valdivieso4; Mauro Taborelli4; Paolo Chiggiato4; Ilya Korolkov5; Ramon Miquel6; Francis Perez7; Montse Pont8; teresa Puig9; Sergio Calatroni4
1 ICMAB - CSIC 2 ICMAB-CSIC 3 ICMAB 4 CERN 5 The Barcelona Institute of Science and Technology (BIST) (ES) 6 IFAE 7 ALBA Synchrotron 8 CELLS-ALBA 9 CSIC
Corresponding Author: [email protected]
CERN has launched the FCC Innovation Study R&D program that will support the feasibility study for the FCC-hh, a new circular hadron collider with 100 km circumference where 16T superconduct- ing magnets will steer proton bunches producing center-of-mass collision energies of 100TeV. Part of
Page 8 FCC Week 2021 / Book of Abstracts
this R&D initiative is to rethink the design of the beam-screen chamber, a stainless steel pipe neces- sary to thermally shield the cold bores of the superconducting dipole magnets from the synchrotron radiation emitted by the accelerated protons. The charged particles will induce 1 GHzRFimage currents into the pipes walls, whose wake fields endanger the beam stability. To counteract this effect, the interior of a beam-screen chamber is coated with a highly conductive material. Within a consortium formed in 2017 between ALBA synchrotron, the institute of high energy physics, the polytechnic university of Barcelona, the institute of material science of Barcelona and CERN, we have demonstrated the benefit of replacing the conventional beam-screen coating material, Cu,with REBa2Cu3O7-x (RE = rare earth) Coated Conductors (CCs) in order to increase the beam stability margin. In this talk, we present the consortium achievements over these years [1], where we have worked to- wards understanding the high-field microwave response of CCs, and we have developed hybrid CC / Cu geometries that limit trapped field and present lower than Cu surface resistances. Our findings have placed CC’s technology as a solid candidate to replace Cu as the low surface-impedance coat- ing of the FCC-hh beam-screen. We will also present how our research in CC’s microwave response under the extreme conditions found in the FCC [2], together with the large-area CC surface coating technology being developed within the consortium, benefits other areas of high-energy physics such as Axion detection. [1] T. Puig et al, Supercond. Sci. Technol. 32 (2019) [2] A. Romanov, et al. Scientific reports 10 (2020)
FCC-ee accelerators / 22
FCC-ee collective effects: introduction and overview(including Full Energy Booster)
Author: Mauro Migliorati1
1 Sapienza Universita e INFN, Roma I (IT)
Corresponding Author: [email protected]
Collective effects generated by the high beam intensities for FCC-ee, in particular for theZ-pole configuration, have to be carefully analyzed. We have found that the resistive wall represents ama- jor source of impedance, but also the bellows with RF fingers make another important contribution. With the impedance model evaluated so far for this machine, thresholds for single bunch instabilities have been evaluated. Additionally, the interplay between beam-beam interaction, beamstrahlung and the longitudinal beam coupling impedance has a strong influence on the coherent X-Z instability, which maycom- promise the collider performances. Results of these studies, as well as some mitigation possibilities, will be discussed in detail in the fol- lowing talks. Here an overview of the collective effects and some considerations about the impedance model and the obtained instabilities are presented. Finally a preliminary overview of the collective effects for the FCC-ee booster is discussed, focused, in particular, on the microwave instability threshold with possible mitigating actions.
FCC-ee accelerators / 23
Status and plans for optics corrections and emittance performance
Author: Tessa Charles1
1 University of Liverpool (GB)
Page 9 FCC Week 2021 / Book of Abstracts
Corresponding Author: [email protected]
To achieve ultra-low vertical emittance a highly effective emittance tuning scheme is required. We will describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices.
FCC-hh accelerator / 24
Status and plans for FCC-hh optics studies
Author: Massimo Giovannozzi1
1 CERN
Corresponding Author: [email protected]
In this talk, I review the current status of the FCC-hh ring layout and optics, starting from the nominal situation and the developments undertaken since the publication of the CDR. I also provide the outlook for future studies.
FCC-ee accelerators / 26
First steps towards a collaborative software framework for the FCC-ee simulations: A multicode comparison
Author: Felix Simon Carlier1
1 EPFL
Corresponding Author: [email protected]
The FCC-ee project faces new challenges specific to larges scale lepton colliders, which requiresnew developments of simulation tools. While many different codes exist that address key aspects ofthe FCC-ee project, it is often complicated, if not impossible, to combine these and merge functionali- ties. This talk presents a comparison and benchmarking of several optics codes for the FCC-ee, andex- plores the strategy to create a collaborative software framework with increased functionalities for FCC-ee simulations.
FCC-ee accelerators / 27
Machine Detector Interface Alignment System Update
Author: Leonard Watrelot1
1 CNAM - Conservatoire National des Arts et Métiers (FR)
Corresponding Author: [email protected]
The alignment of the Machine Detector Interface (MDI) is crucial to obtain the desired luminosity but also extremely challenging due to the complexity of this region.
Page 10 FCC Week 2021 / Book of Abstracts
This presentation will highlight the different challenges and difficulties encountered sofarinthe FCC-ee MDI. Then it will give an overview of the existing systems in other similar MDI butalso ideas proposed in projects of future colliders. Finally, it will propose the base for a possible solution to monitor this MDI and some development possibilities.
SRF / 28
Prototyping the Nb coating of the copper Wide Open Waveguide Crab Cavity (WOWCC) for FCC-hh
Authors: Fabian Manke1; Fabio Avino2; Alexej Grudiev1; Ana Teresa Perez Fontenla1; Thibaut Richard1; Alban Sublet1; Mauro Taborelli1
1 CERN 2 École polytechnique fédérale de Lausanne (EPFL) - Switzerland
Corresponding Author: [email protected]
The implementation of suitable crab cavities is an important milestone for the SRF activities inthe feasibility study for a hadronic FCC. The proposed Wide Open Waveguide design [1,2] achieves bunch tilting by deflecting particles in transverse TE-111 like field, optimized between two tapered ridges with a mushroom-shaped cross-section. Its eponymous large apertures furthermore reduce shunt impedances and the confinement of residual higher order modes. Considering the givenre- quirements of geometric precision, heat transport and project scale, a niobium coated copper cavity was chosen. Here, we will present the current state of the dedicated coating system R&D. Numerical studies of the magnetron plasma and sputtering process have established the use of 6 cylindrical cathodes along the cavity as sputtering targets. Sample coatings performed on a reduced 3-cathode set-up achieved a significant improvement of coating quality through High Impulse Magnetron Sputtering [3,4]. More recently, the impact of the simultaneous use of multiple cathodes on the coating characteristics and heat loads has come under investigation, to optimize the specific coating process steps. In parallel, the scale-1 coating system design is being finalized, aiming for a first coating of a WOWCC prototype early next year. [1] A. Grudiev, Proceedings of SRF 2015 [2] K. Papke et al, Phys. Rev. Accel. Beams 22, 072001, 2019 [3] F. Avino et al, Plasma Sources Sci. Technol. 28, 01LT03, 2019 [4] F. Avino et al, Thin Solid Films 706, 138058, 2020
FCC-ee accelerators / 29
Key Vacuum Surface Parameters for FCC-ee Operation
Author: Roberto Cimino1
1 INFN e Laboratori Nazionali di Frascati (IT)
Corresponding Author: [email protected]
FCC-ee has an unprecedented design and operational parameters. For this reason, it is prone to suffer from beam-vacuum chamber detrimental interaction potentially affecting its performance. Vacuum, impedance, e-cloud instabilities are some of the issues that need to be mitigated from the design phase. This contribution analyses some of the requirements accelerator vacuum walls must obeyto be compliant with design parameters. Additional R&D studies are suggested in order to be able to feed the running simulations with realistic estimates of the relevant surface parameters.
Page 11 FCC Week 2021 / Book of Abstracts
FCC-ee accelerators / 30
Overview, plan and open questions
Author: Manuela Boscolo1
1 INFN e Laboratori Nazionali di Frascati (IT)
Corresponding Author: [email protected]
The design of the interaction region of the positron-electron future circular collider must comply with various important constraints, imposed by high beam energy, high luminosity, need for polar- ization, and crossing scheme. An overview of the MDI design will be presented with a picture of the recent results and ongoing studies. In particular, the mechanical model of the MDI has been started recently, first considerations and open questions will be addressed. The status and plans forthe beam backgrounds studies will be presented together with the measures for its mitigation.
FCC-ee accelerators / 31
SuperKEKB collimation system
Author: Takuya Ishibashi1
1 KEK
Corresponding Author: [email protected]
In the SuperKEKB, which is a two-ring collider consisting of 4 GeV positron and 7 GeV electron storage ring, movable collimators have been installed in order to reduce the backgrounds in the detector and avoid quenches in superconducting final focusing magnets. Therefore, the movable collimators are one of the indispensable components in SuperKEKB for the machine operations. We developed horizontal and vertical collimators having a pair of horizontally or vertically opposed movable jaws with radio-frequency shields, and the system has generally functioned as expected up to approximately 1 A in the beam current. In this talk, the design and experiences about the collimators are mainly presented.
Technology R&D / 32
Powering strategy - focus on main dipole magnets
Authors: Davide Aguglia1; Manuel Colmenero Moratalla1; Francisco Rafael Blanquez Delgado1
1 CERN
Corresponding Author: [email protected]
The talk focuses on the powering of the main dipole magnets for the FCC-ee collider. The choiceof the number of circuits is analysed considering the impact given by the different cable lengths (cost and electrical losses). The major design compromises on the powering against the number ofturns selection in the dipole magnets are illustrated. Finally, a solution with power converters trims for tapering is analysed. A brief analysis is also carried out for the powering of the main dipoles of the booster, which present the specificity of being cycled.
Page 12 FCC Week 2021 / Book of Abstracts
FCC-ee accelerators / 33
Arc vacuum system and synchrotron radiation
Author: Roberto Kersevan1
1 CERN
Corresponding Author: [email protected]
An analysis of the synchrotron radiation spectra and photon power and flux distribution along one sample sector of 140 m length representative of the FCC-ee arcs has been carried out using the ray- tracing montecarlo code SYNRAD+. The results of these simulations have then been used to derive the photon stimulated desorption (PSD) for different conditioning times, for the Z-pole machine. The pumping efficiency of several pumping configurations has also been carried out, usingtheray- tracing montecarlo code Molflow+. The beneficial effect of NEG-coating in reducing thePSDgas load is evident, allowing a dramatic reduction of the number of lumped pumps needed to reach a sufficiently low pressure in a short time. A list of prototypes and tests required in order tovalidate the proposed configuration is given.
FCC-ee accelerators / 34
Filling schemes through injector chain
Authors: Salim Ogur1; Michael Benedikt1; Iryna Chaikovska2; Paolo CraievichNone; Alexej Grudiev1; Katsunobu Oide3; Yannis Papaphilippou1; Frank Zimmermann1
1 CERN 2 CNRS/IJCLab 3 High Energy Accelerator Research Organization (JP)
Corresponding Author: [email protected]
FCC-ee aims extremely high luminosities during its all operational modes: Z, W, H and top quark. Especially, the Z run steps forward amongst the other stages due to the very high stored charge, i.e. 1.4 A, in the collider. Therefore, the injectors need to provide the collider fill from the scratchas well as maintain the luminosity at the peak thru operation by making use of the quasi-continuous top-up injection. This talk will stress on the operational modes and compare the CDR versusthe newly suggested injection filling schemes. The new bunch schedules put forward in order tofill the collider in a shorter time interval and to profit from the injectors at maximum which becomes crucial during the restore of the charge loss due to collisions, scatterings and so on. All in all, we will discuss the pros and cons of the multi-bunch acceleration in an RF pulse of the linac and its impact to the whole FCC-ee complex.
Plenary session / 35
Roadmap for the FCC Feasibility Study
Author: Michael Benedikt1
1 CERN
Corresponding Author: [email protected]
Page 13 FCC Week 2021 / Book of Abstracts
Plenary session / 36
The status of global FCC collaboration
Author: Emmanuel Tsesmelis1
1 CERN
Corresponding Author: [email protected]
FCC-ee accelerators / 37
Synchrotron Radiation studies for the FCC-ee arc with FLUKA
Author: Barbara Humann1
Co-author: Francesco Cerutti 2
1 Vienna University of Technology (AT) 2 CERN
Corresponding Author: [email protected]
The FCC-ee arc region is significantly impacted by the synchrotron radiation (SR) emitted bythe electron and positron beams. In order to assess its actual effect on the magnets and tunnel envi- ronment, FLUKA simulations were performed for the most challenging case of top-pole operation at 182.5GeV. In this presentation, the advantages and disadvantages of two different solutions are discussed. One layout features localized photon absorbers, while the other one embeds a continuous shielding around the vacuum chamber, comparable to the LEP model. For evaluating critical situations and identifying potential showstoppers, the power deposited on the various machine components as well as dose and particle fluence 3D maps are presented, including radiation levels relevant to electronics. Finally, an outlook of pending challenges and next steps is given.
Technical infrastuctures / 38
Status of Electricity and energy management work package
Author: Jean-Paul Burnet1
1 CERN
Corresponding Author: [email protected]
The FCC machines will require a strong electricity supply for power demand in the order of400to 600MW. A Detail study was performed with 3 sub-stations at 400kV as delivery points. FCC-hh and FCC-ee were considered and a strong baseline was achieved. For Phase 2 of the study, the work package will focus on alternative scenarios and on optimization. The alternative scenarios concern the number of delivery points and sub-station voltage, the transmission between points and the failure scenarios to secure the electricity supply, the integration of energy production and storage, the immunity against transient disturbances, and the power quality. The objectives of phase 2 are to optimize the supply of electricity, to optimize the electrical network for both machine FCC-ee and FCC-hh, and to propose a robust powering scheme.
Page 14 FCC Week 2021 / Book of Abstracts
Technical infrastuctures / 40
Technical Infrastructure operations today and in the future
Author: Jesper Nielsen1
1 CERN
Corresponding Author: [email protected]
Operation of the technical infrastructure is often a task done in the shadow of accelerator operations, until, of course, the inevitable breakdown. We need electricity, cooling, ventilation, IT systems and much more to run our very complex accelerator complex, but how do we keep the faults to a minimum? In this talk we will touch base on how operation of the technical infrastructure at CERN is done, the limitations we have due largely to the fact that our infrastructure is a mix of brand new very high-tech installations and old equipment from the very beginning of CERN. We will hear about where we are today and what will be possible to do in the future when operating the FCC and the rest of CERN’s technical infrastructure. How to get eyes on the field? Can you operate a drone from the central control room? Whatifwe could predict faults before they happen? are some of the questions we will ask ourselves in a near future.
FCCIS WP3 (Integrate Europe) / 41
Mining the Future - status and progress
Author: Robert GallerNone
Corresponding Author: [email protected]
Currently excavated material from tunnel construction in EU countries and Switzerland is treated as “waste”. In accordance with applicable law, waste is to be disposed of if it is not sent to the end of the waste. The process to obtain the end of waste is not followed in most cases, as it is administratively and technically demanding and is therefore associated with considerable costs. As a result, the use of excavated material is currently not economically viable in most cases. Due to the high volumes of “mineral raw materials / waste” from underground infrastructure projects and the associated land- fill areas required, innovative measures are required in order to initiate sustainable change inthis regard. FCC is geologically in the middle of the Molasse. The “molasse sediments” extend from the French Alps via Switzerland to Austria. Preliminary explorations revealed six different types of heteroge- neous sedimentary rocks around the FCC tunnel project. So far there is no industrial application for molasses sediments. As part of the FCC tunnel project, 9 million m3 of rock would have to be deposited. In order to create new ways of using excavated material from tunnel construction, CERN has started the EU project FCC-IS. As part of the research task “Mining the Future” at CERN, an international competition is being held. The competition aims to help identify innovations for the use of excavated materials. Theaimisto make future underground construction projects both more resource-efficient and more cost-efficient and to strengthen European industry. At the Chair of Subsurface Engineering at the MUL, a large number of tests are carried out in the geotechnical laboratory, which are used for tunnel planning on the one hand, but also for the use of the material on the other. Dipl.-Ing. Maximilian Haas, employee at CERN and a graduate of Montanuniversität Leoben, Austria selected all samples; furthermore he worked in the laboratories of the University of Geneva and at the ETH Zurich as part of his dissertation on the chemical and mineralogical composition of the expected tunnel excavation material. If we succeed in reversing the trend towards the mandatory use of tunnel excavation material, if this is not technically impossible, and thus giving this topic higher priority, an important step would be achieved.
Page 15 FCC Week 2021 / Book of Abstracts
The development of economically viable routes for innovative tunnel construction enables asignifi- cant reduction in the excavated material to be dumped. The business plan won from the competition for the use of the “molasses sediments” is intended to serve as an example for other projects. Due to the disclosure of all data, this should create a basis for new pilot projects. In autumn 2022 a seminar and the award ceremony for the competition to find the most innovative proposals for tunnel excavation recovery will take place at ZaB – Zentrum am Berg, a large scale underground research facility in Austria.
FCC-ee accelerators / 42
Progress in the design of the linacs and electron sources for the FCC-ee injector complex
Author: Alexej Grudiev1
1 CERN
Corresponding Author: [email protected]
Progress in the design of the linacs and electron sources for the FCC-ee injector complex will be reported
SRF / 43
The SWELL cavity development
Author: Igor Syratchev1
Co-authors: Franck Peauger 1; Olivier Brunner 1; Ivan Karpov 1
1 CERN
Corresponding Author: [email protected]
The Slotted Waveguide ELLipltical (SWELL) cavity promises a good response to both dampthe higher-order modes efficiently to avoid beam instabilities and provide high accelerating gradient. The same cavity can be used for all five operating regimes of FCC_ee. The proposed installation scenario foresees a gradual installation of cavities and a rather elegant reuse of the high RF power stations. The RF system evolution towards the higher energy machines leaves the door open to‘sim- plified’ SWELL cavities (i.e. without the HOM extraction system) and to standard multi-cell high gradient elliptical cavities. The proposed four quadrant technology brings several advantages asit avoids the welding joints in the area of high magnetic field, eases the Nb coating of the machined copper quadrants and does not require any helium vessel.
FCCIS WP4 (Impact & Sustainability) / 45
Introduction on the socio-economic impact assessment model
Authors: Emanuela SirtoriNone; Emanuela SirtoriNone
Corresponding Authors: [email protected], [email protected]
Introduction on the socio-economic impact assessment model
Page 16 FCC Week 2021 / Book of Abstracts
FCCIS WP4 (Impact & Sustainability) / 46
Regional and territorial benefit identification: approach and method
Author: Amandine Florence ChevalierNone Corresponding Author: [email protected]
As a research infrastructure, FCC would create socio-economic impacts both at global level as well as at regional and territorial levels. The aim of our work is to identify territorial (in France andin Switzerland) and regional benefits. This presentation focuses on the approach and method that will be applied. Based on a territorial development approach, we identify potential regional benefits and potential local effects during the different phases of the FCC project: feasibility and pre-construction studies, construction, deploy- ment and operation phases, with a prospective point of view for the last one, as FCC should be operational by 2040. This analysis of local/regional socio-economic impacts will be performed based on findings of a complementary more global cost-benefit analysis. The work will be carried out inspired by the analysis of estimated socio-economic impacts ofthe LHC/HL-LHC programme, mainly for land use planning, use of resources, territorial synergies and involved stakeholders. Our ex-ante analysis considers what already exists in the local territorial area as scientific, industrial, economic activities which could be linked to FCC and qualified interest groups and host-state notified bodies. Interfaces with local partners to develop regional development scenarios together will be established.
FCCIS WP4 (Impact & Sustainability) / 47
Spatial impact analysis of Large Research Infrastructures: A case study on SRF cavities
Author: Gabriele PiazzaNone Corresponding Author: [email protected]
What is the spatial footprint of the socio-economic benefits of High-Energy Physics Research Infras- tructures? This presentation discusses the preliminary stages of LSE research on FCC’s potential spatial socio-economic benefits by focusing on SRF cavities production, one of the key technologies for the FCC-ee.
FCC-ee accelerators / 48
Status of bellows and flanges impedance studies
Author: Chiara Antuono1 Co-authors: Mauro Migliorati 2; Carlo Zannini 3
1 Sapienza Universita e INFN, Roma I (IT) 2 University of Rome ”LA SAPIENZA” 3 CERN
Corresponding Author: [email protected]
In the framework of the FCC project, the development of an accurate beam coupling impedance model of the accelerator elements represents an important aspect for reaching the machine design performances. A significant contribution to the total coupling impedance is provided by bellows and vacuum
Page 17 FCC Week 2021 / Book of Abstracts
flanges, for which an accurate electromagnetic characterization is required. In this work a step-by-step approach, from simplified to complex models involving 3D electromag- netic simulations, is discussed, and an estimation of the beam coupling impedance of a simplified bellow model is presented.
Technical infrastuctures / 49
Geodetic studies for FCC
Author: Helene Mainaud Durand1
1 CERN
Corresponding Author: [email protected]
The FCC site will be ten times larger than the current CERN site; most of the geodetic reference frames and infrastructure go back to LEP and a new design is required. A collaboration has been put in place between CERN, Swisstopo, ETH Zürich and HEIG-Vd to perform part of these studies. In this talk, I will first remind the motivation of such geodetic studies before introducing thecol- laboration put in place: presenting the collaborators, the objectives, the defined deliverables and milestones. The status and technical progress achieved on these studies will be provided. Iwillcon- clude with a description of the organization of the WP and a review of its activities for the 2021-2025 period and above.
Physics, Experiments & Detectors / 50
What software for ’Higgs and Electroweak Factories’?
Author: Gerardo Ganis1
1 CERN
Corresponding Author: [email protected]
The European Strategy Update has indicated an e+e- electroweak and Higgs factory as the nextcol- lider to be built in Europe. The proposed projects are usually classified on whether the underlying accelerator machine is linear or circular. For all these possible facilities software is a crucial com- ponent to understand the potentiality and issues of the proposed solutions. Despite the differences coming from the underlying collision source, software-wise these facilities have a lot in common, to the point that they are at the core driving engine of a project for a common software for future collid- ers, key4hep, which aims to succeed where LHC did not completely succeed, i.e. standardising HEP software. In this talk we will present the status of these activities, including the adoption strategies by the various projects, and discuss the challenges ahead, with a particular eye on FCCee.
Physics, Experiments & Detectors / 51
Bc -> tau nu at FCC-ee
Author: Donal Hill1
1 EPFL - Ecole Polytechnique Federale Lausanne (CH)
Page 18 FCC Week 2021 / Book of Abstracts
Corresponding Author: [email protected]
Z-pole operation at FCC-ee represents an unprecedented opportunity for heavy flavour physics, as the production of 5 × 1012 Z bosons will result in a sample of 8 × 1011 b-quark pairs. All species of + B hadron will be produced at FCC-ee, including the doubly heavy Bc meson. The purely leptonic decays of this meson, which proceed in the Standard Model via annihilation of the ¯b and c quarks, + → + have not yet been observed experimentally. The Bc τ ντ decay is of particular interest, as its decay rate is highly sensitive to potential New Physics contributions from mediators such as charged + → + Higgs bosons or leptoquarks. A measurement of the Bc τ ντ branching fraction at FCC-ee has the potential to rule out large regions of New Physics parameter space, and either confirm or refute the indications of New Physics in b → cτντ transitions. This talk describes a complete feasibility B + → + study for the measurement of (Bc τ ντ ) at FCC-ee, where precision estimates are given as a function of the number of Z bosons produced. This work represents the first FCC-ee analysis touse common software tools from EDM4hep through to final analysis.
Physics, Experiments & Detectors / 52
ARC: a solution for particle identification at FCC-ee
Author: Roger Forty1
1 CERN
Corresponding Author: [email protected]
A novel RICH detector concept will be presented, suitable to satisfy the particle identification re- quirements for an experiment at FCC-ee (or other future collider). Particular attention has been taken on achieving a compact and low-mass detector while maintaining exquisite resolution. Preliminary engineering considerations and predicted performance will be shown, along with the compelling lines of R&D that would help to realize this concept.
Physics, Experiments & Detectors / 53
Long-lived particles at FCC
Author: Rebeca Gonzalez Suarez1
1 Uppsala University (SE)
Corresponding Author: [email protected]
Long-lived particles have significant enough lifetimes as to, when produced in collisions, leavedis- tinct signatures in the detectors. Driven by increasingly higher energies, trigger and reconstruction algorithms at particle colliders are optimized for increasingly heavier particles, which in turn, tend to be short-lived. This makes searches for long-lived particles difficult, usually requiring dedicated methods andsome- times also hardware to spot them. However, taking upon the challenge brings enormous potential, since new, long-lived particles feature in a variety of promising new physics models that could an- swer most of the open questions of the standard model, such as: neutrino masses, Dark Matter, or the matter-antimatter imbalance in the Universe. Crucial physics cases connected to long-lived particles will be accessible at the FCC. The complemen- tarity of the three different stages of the FCC provides unique potential to discover and pin down these particles, and maybe solve long-standing problems of the SM. This talk will describe the current landscape and possible areas to contribute to in the next fewyears. Three interesting examples are highlighted: Heavy Neutral Leptons, Hidden Sectors connected to
Page 19 FCC Week 2021 / Book of Abstracts
Dark Matter, and exotic Higgs boson decays. The exploration of long-lived particles attheFCC-ee motivates an out-of-the-box experimental optimizations that will also be discussed.
FCC-hh accelerator / 54
Status and plans for FCC-hh collimation
Authors: Andrey Abramov1; Roderik Bruce1; Anton Lechner1; Federico Carra1; Francesco Cerutti1; James Hunt1; James Molson2; Jorge Guardia Valenzuela3; Michele PasqualiNone; Mohammad VarastehNone; Stefano Redaelli1
1 CERN 2 University of Malta (MT) 3 Universidad de Oviedo (ES)
Corresponding Author: [email protected]
The Future Circular Collider (FCC-hh) should collide 50 TeV proton beams with a total stored beam energy of 8.3 GJ, a factor 28 higher than what has been achieved in the LHC. This is an unprecedented challenge for the control of beam losses, since even a tiny beam lossrisks causing a quench or even damage. This talk discusses the present status of the design of the FCC-hh collimation system, reviewing previous studies and highlighting topics for future study.
FCC-ee accelerators / 55
Overview and layout
Author: Paolo CraievichNone Corresponding Author: [email protected]
The FCC-ee injector complex has to deliver the beam for top up injection in the two colliderrings supporting a beam duration of about one hour on the Z-pole and up to 12 minutes for higher energy modes of operation. In addition, the injector also has to allow a fairly rapid fill-up from zero within half an hour at most. The high beam current of this collider create challenging requirements onthe injection chain. After publication of the CDR in 2019, all aspects of the linac needed to be carefully reconsidered and revisited, including the injection time structure. In this talk I will give an overview of the status of the injector complex design and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration.
Physics, Experiments & Detectors / 56
Performance of a Crystal + Dual readout Calorimeter system at FCC-ee
Author: Marco Toliman Lucchini1
1 Università & INFN, Milano-Bicocca (IT)
Corresponding Author: [email protected]
Crystal calorimetry has a long history of pushing the frontier of high energy resolution measure- ments for EM particles. Recent technological developments in the fields of crystal manufacturing and photodetector developments (SiPMs) have opened new perspectives on how a segmented crystal
Page 20 FCC Week 2021 / Book of Abstracts
calorimeter with dual-readout capabilities could be exploited for particle detectors at future collider experiments like FCC-ee. In this contribution, we will discuss how a segmented EM crystal calorime- ter can be cost-effectively integrated√ with the fiber-based√ calorimeter of the IDEA detector to achieve an energy resolution of 3%/ E for EM particles and 27%/ E for neutral hadrons. We will also show how the extension of the dual-readout method in such a longitudinally segmented hybrid calorimeter can achieve the target energy resolution of about 3-5\% for 50 GeV jets and discuss the potential of such calorimeter in the context of future particle flow algorithms.
Technical infrastuctures / 57
FCC-ee & hh cryogenic system conceptual design, status & per- spectives
Author: Laurent Jean Tavian1
Co-authors: Laurent Delprat 1; Krzysztof Brodzinski 1
1 CERN
Corresponding Author: [email protected]
Capitalising on the cryogenic operation experience of the LHC and thanks to the promising results of the R&D efforts, the first phase of the Future Circular Collider (FCC) study presents in its Conceptual Design Report (CDR) published in January 2019 a clear route to a post-LHC machine, which shall be housed in a new 100km circumference tunnel. Regarding the cryogenic system, it is describing the proposed architecture required by the implementation of the staged FCC programme, which would integrate in sequence a lepton (FCC-ee) then a hadron (FCC-hh) collider in the same tunnel with related cryogenic system upgrades respectively. This presentation will cover the current status of the study so far, gathering the cryogenic conceptual design work already achieved. Foreseen organization of the cryogenics work package within the Technical Infrastructure Working Group Pillar should be addressed. Objectives for the second study phase, including tentative timeline and next steps should be covered.
FCC-ee accelerators / 58
FCC-ee booster as ultimate storage ring photon source
Author: Sara Casalbuoni1
Co-author: Frank Zimmermann 2
1 European XFEL 2 CERN
Corresponding Author: [email protected]
Many synchrotrons are upgrading their lattice to reach lower horizontal emittances below 100pm rad. The project foreseeing the lowest emittance is PETRA IV with the aim of reaching about10pm rad. The very large circumference of the FCC-ee booster combined with damping wigglers allowsto reach a horizontal beam emittance down to 0.5 pm rad. This would push the diffraction limitfrom 10 keV (1 Angstroem) achievable with PETRA IV down to 100 keV (0.1 Angstroem). In this contribution, the study of a possible use of the FCC-ee booster as ultimate storage ring photon source is presented. The performance in terms of photons output is compared with the most advanced existing and planned light sources.
Page 21 FCC Week 2021 / Book of Abstracts
FCC-ee accelerators / 59
Parameters - update and plan
Author: Dmitry Shatilov1
1 Budker Institute of Nuclear Physics (RU)
Corresponding Author: [email protected]
The main parameters of the FCC-ee collider are fixed in the CDR, but this does not mean that theywill not change anymore. Further and deeper consideration of this project reveals new problems, both physical and technical, and new ideas appear. This mainly concerns the operation at low energy, where a large total beam current can lead to various collective instabilities. We will discuss some of the problems that have emerged recently and possible solutions. Our goal is to preserve the declared luminosity, but in this case it may be necessary to revise some of the collider parameters. We will also discuss the remaining open issues and further plans to optimize the FCC-ee.
FCC-ee accelerators / 60
Robust Modelling of FCC-ee with Analytical Equations and Sim- ulations
Authors: Leon Van Riesen-Haupt1; Rogelio Tomas Garcia1; Tessa Charles2; Helmut Burkhardt3; Katsunobu Oide4; Tobias Hakan Bjorn Persson1; Frank Zimmermann1
1 CERN 2 University of Liverpool (GB) 3 Albert Ludwigs Universitaet Freiburg (DE) 4 High Energy Accelerator Research Organization (JP)
Corresponding Author: [email protected]
We present the latest results obtained from comparing various codes used for simulating the FCC-ee optics. The three codes used for this study are SAD, MADX and the MADX PTC implementation. The aim of the comparisons is to determine how reliably the codes can simulate various aspectsof the accelerator, including the emittance, the linear optics and the dynamic aperture. We willalso present the latest finding from applying analytical formulas to the FCC lattice to estimate emittance growth for different kinds of magnet errors.
SRF / 61
Hydroforming Elliptical SRF Cavities : Studies on 1.3 GHz and Beyond
Author: Marco Garlasche’1
1 CERN
Corresponding Author: [email protected]
The Hydroforming process is a well-established acquaintance in the SRF world. Recently, progress has been performed in the ability to better tune such process; namely through enhanced quality of the inherent fabrication processes, and through the implementation of large deformation numerical analyses for a finer definition of process parameters.
Page 22 FCC Week 2021 / Book of Abstracts
Presentation will focus on the ongoing analyses and on the process definition, for eventual produc- tion of cavities in the 1.3GHz to 400MHz range
EASITrain / 65
Bridging research & industry: Creating value from FCC‘s tech- nologies for the general public
Author: Linn KretzschmarNone Corresponding Author: [email protected]
Benefits derived from CERN’s FCC research go beyond building infrastructures to answer offunda- mental research questions. A crucial question is how - apart from learning more about our universe - can society benefit directly from a new particle collider project? While not necessarily apparent at first glance, research on new high technologies comes with profound economic impact onindustry and knowledge acquired from developing these technologies needs be spread and appropriated to benefit the public. For the past 4 years, the Vienna University of Economics and Business has been carrying out nu- merous research projects to identify new market opportunities for technologies developed for the collider. Funded by the European Union as part of the EASITrain innovative training network, the search for new application fields included carrying out well above 100 in-depth expert interviews, interacting with enthusiast communities and building a bridge between research institutions and industrial partners to connect knowledge sources. We believe that the construction of the FCC does not only benefit research but value is created beyond that as the know-how can be utilized byin- dustrial partners to cater to new needs, tap new markets or improve the companies’ efficiency and competitiveness. Higher cost effectiveness and leveraging further markets furthermore translates into lower manufacturing costs of a future high-energy particle collider, ultimately creating a win- win situation for all parties.
EASITrain / 66
Training the professionals of the future
Author: Marina Putti1
1 University of Genova
Corresponding Author: [email protected]
EASITrain / 67
WP7 results and prospects
Corresponding Author: [email protected]
FCC-eh / 68
FCC.eh: Update and ERLs
Author: Max Klein1
Page 23 FCC Week 2021 / Book of Abstracts
1 University of Liverpool (GB)
Corresponding Author: [email protected]
FCC-eh / 69
LHeC Racetrack as Injector to FCC-ee
Author: Yannis Papaphilippou1
1 CERN
Corresponding Author: [email protected]
FCC-eh / 70
Interaction Region Design Optimization
Author: Kevin Daniel Joel Andre1
1 University of Liverpool (GB)
Corresponding Author: [email protected]
FCC-eh / 73
Probing Spacetime with Colliders
Author: nathan sherrill1
1 University of Sussex
Corresponding Author: [email protected]
FCC-ee accelerators / 74
FCC-ee Aperture and Collimation
Authors: Andrey Abramov1; Felix Simon Carlier2; James Molson3; Maitreyee Mahasweta Moudgalya4; Michael Hofer1; Roderik Bruce1; Stefano Redaelli1; Tatiana Pieloni5
1 CERN 2 EPFL 3 University of Malta (MT) 4 EPFL - EPF Lausanne 5 EPF Lausanne
Page 24 FCC Week 2021 / Book of Abstracts
Corresponding Author: [email protected]
The FCC-ee design pushes parameters such as the beam energy, the stored beam energy, andthe total synchrotron radiation power beyond the values achieved at existing machines. Ensuring safe machine operation and minimising background to detectors are important requirements. The first studies of the aperture limitations and the first considerations for a collimation system in theFCC- ee are presented in this talk. The aperture studies include an estimation of the beam stay clearand momentum acceptance, taking into account mechanical and optical tolerances and imperfections. The collimation studies are focussed on a preliminary design for a dedicated halo collimation system and the software tools that can be used for collimation simulations in the FCC-ee.
FCC-ee accelerators / 75
Experience at SuperKEKB
Author: Jacqueline Keintzel1
1 Vienna University of Technology (AT)
Corresponding Author: [email protected]
Possible circular colliders for the post-LHC era at CERN are being explored within the framework of the Future Circular Collider (FCC) feasibility study. The first stage of the FCC integrated project is the FCC-ee, an ambitious electron-positron collider with a circumference of approximately 100 km. Certain key concepts of the FCC-ee design can be demonstrated and tested at existing facilities, such as at SuperKEKB at KEK. Understanding the crab-waist collision scheme, testing optics control and emittance tuning techniques offer invaluable insights for the FCC-ee design optimisation and its operational procedures. The experience at SuperKEKB will be an essential input to the FCCFea- sibility Study Report. This talk will highlight already successfully performed studies at SuperKEKB and will give an overview of possible future tests for FCC-ee.
FCC-ee accelerators / 76
Science case for high-energy photons
Author: Anders Madsen1
1 European XFEL, Germany
Corresponding Author: [email protected]
I will present the case for performing experiments with hard X-ray synchrotron radiation. The spectral brightness of existing undulator-based storage rings in the hard X-rays regime is limiting the applications above ~30 keV where the beam coherence becomes small. This results in limita- tions of the flux available for many experiments. In particular, X-ray imaging could benefitfrom the availability of intense coherent beams in this energy range but also scattering experiments will gain tremendously when penetration power and a wide range of accessible momentum transfer are required.
FCC-ee accelerators / 77
Optics and layout - update and plan
Author: Katsunobu Oide1
Page 25 FCC Week 2021 / Book of Abstracts
1 High Energy Accelerator Research Organization (JP)
Corresponding Author: [email protected]
A comparison is made on the beam optics, dynamic aperture and luminosity performance for several layouts of the collider ring. If the periodicity of the lattice is preserved, no exceptional issue has been found; the luminosity is simply limited by the synchrotron radiation corresponding to the ring circumference. Some studies on the lattice periodicity and shortening the distance between ee’s and hh’s IPs willbe introduced. Subjects for the lattice design for further detail will be discussed.
SRF / 78
Superconducting Thin Films Studies at CERN
Authors: Alban Sublet1; Antonio Bianchi1; Carlota Pereira Carlos2; Carmine Senatore3; Dorothea Fonnesu4; Fabian Manke1; Guillaume Jonathan Rosaz1; Leonel Marques Antunes Ferreira1; Lorena Vega Cid1; Lucia Lain Amador1; Marco BonuraNone; Mathieu Therasse1; Mauro Taborelli1; Pablo Vidal Garcia5; Stephanie Fernandez1; Stewart Leith1; Thibaut Richard1; Walter Venturini Delsolaro1
1 CERN 2 FCT Fundacao para a Ciencia e a Tecnologia (PT) 3 University of Geneva 4 Universitaet Siegen (DE) 5 Centro de Investigaciones Energéti cas Medioambientales y Tecno
Corresponding Author: [email protected]
Thin film coated superconducting radiofrequency (SRF) accelerating cavities are among themost promising technologies to provide a cost efficient accelerator in the framework of the Future Circu- lar Collider (FCC) study. We will give a broad overview of the currently on-going R&D topics such as the optimization of surface treatment by electropolishing, the elaboration of niobium thin films by High Power Impulse Magnetron Sputtering (HiPIMS) with an emphasis on the effect of the ion bombardment energyand at last the first results regarding the elaboration of A15 materials (Nb3Sn, V3Si) using bi-polar HiP- IMS coating technique. Finally we will discuss the approach to scale up the current state-of-the art coating techniques to- wards 400MHz cavities as well as to the newly proposed Slotted Waveguide Elliptical cavity (SWELL) design presenting the first results of HiPIMS Nb coatings on 400MHz elliptical cavities.
SRF / 79
Cavity Engineering & Fabrication at CERN
Author: Said Atieh1
1 CERN
Corresponding Author: [email protected]
Several projects at CERN require developments of new or spare superconducting RF cavities, for the LHC consolidation, the LHC High Luminosity upgrade (HL-LHC) and the Future Circular Collider (FCC) studies. CERN has in recent years increased its effort into SRF technologies R&D as well as the related infras- tructure. From highly technical design and fabrication engineering support to prototyping/developments
Page 26 FCC Week 2021 / Book of Abstracts
and on-going manufacturing collaboration. Nowadays, complex metal components utilizing state- of-the-art metal fabrication technologies, including shaping, machining and assembly via electron beam welding has been manufactured and its related technologies has been deployed.
FCCIS WP3 (Integrate Europe) / 80
Placement: Report from the review and next steps
Authors: Johannes Gutleber1; Volker Mertens1; Pierre BoillonNone
1 CERN
Corresponding Author: [email protected]
The FCC infrastructure is based on a 90 to 100 km circumference tunnel, connected via moreorless regularly spaced access shafts with up to 12 surface sites. Placement of this infrastructure needsto take into account the underground geological conditions, territorial and environmental constraints as well as the physics performance that can be reached with the colliders. Final optimisation will also have to balance cost, risk and other aspects. Placement studies have commenced already during the conceptual design phase in cooperation with host state authorities. They were supported by civil engineering studies and the development of a geological model for the Geneva basin. Starting from the CDR baseline layout, various geometries and placements have been analysed. They include two different approaches: a mirror-symmetric 12-site layout and a layout with a 90 degrees super- periodicity with 8 sites. A major layout and placement review was held on 7 and 8 June 2021, bringing together members of the FCC International Advisory Board, representatives of the host states and technical experts to review progress and confirm the methods applied. The development of a preferred scenario tobe validated with subsurface investigations and with regional stakeholders is the next logical step. The purpose of this presentation is to outline the main elements of this project review.
FCC-ee accelerators / 81
Beam-beam background and beamstrahlung studies at FCC-ee
Author: Andrea Ciarma1
1 CERN
Corresponding Author: [email protected]
The study of unavoidable backgrounds of various sources that may affect the quality of the usefulcol- lider data is essential to assess its success. The design and optimization of both the detector andthe machine therefore require realistic estimations of beam induced backgrounds. The development of interfaces for the relevant existing codes with the detector and physics simulation software (FCCSW) will allow a direct evaluation of the impact of beam backgrounds in the detector. The current status of the work on beam background is presented, showing preliminary results on the radiation pro- duced at the IP. First results on radiative bhabhas with tracking of spent beam particles will also be presented.
EASITrain / 82
Page 27 FCC Week 2021 / Book of Abstracts
Advanced Fabrication and Vacuum Compatibility of Tl-1223 Su- perconducting Thin Films for the Future Circular Collider (FCC- hh) Beam Screen
Author: Aisha SabaNone
Co-authors: Alessandro Leveratto 1; Marina Putti 2; carlo ferdeghini 3; Sergio Calatroni 4; Marcel Himmerlich 4; Stephanie Fernandez 4; Ruggero Vaglio 5; Sigrid Holleis 6; Michael Eisterer ; Johannes Bernardi ; Emilio Bellingeri 1
1 CNR-SPIN 2 University of Genova 3 CNR 4 CERN 5 1950 6 Vienna University of Technology
Corresponding Author: [email protected]
A.Saba1,2, A. Leveratto1, C. Ferdeghini1, M. Putti1,2, S. Calatroni3, M. Himmerlich3, S.Fernandez- Peña3, R. Vaglio1,4, S. Holleis5, M. Eisterer5 , J. Bernardi6 and E. Bellingeri1 1 CNR SPIN, I-16152 Genoa, Italy 2 University of Genova, Physics Department, I-16126 Genoa, Italy 3 CERN, European Organization for Nuclear Research, 1211 Geneva 23, Switzerland 4 University of Naples Federico II and INFN, Physics Department, I-80125 Naples, Italy 5 Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria 6USTEM, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria The properties of high-temperature thallium-based superconductors are being studied in viewofa possible coating for the beam shield of the future Circle Collider (FCC-hh). Research on the FCC-hh is focused on achieving a centre-of-mass energy of 100 TeV by colliding beams (guided by 16 T super- conducting magnets). The beam stability and the safety of the cryogenic systems are two of themost critical aspects in such accelerators. According to theoretical estimations, the surface resistance of copper as currently used in the LHC at CERN may not be low enough to cope with the instabilities in the envisaged temperature range (40-60 K) of the FCC-hh. Therefore, high-temperature supercon- ducting coatings have been proposed as alternative low-resistance materials. We have been fabricating and analysing thallium-based superconducting samples to contribute to this research. The different techniques used to synthesise Tl-1223 superconducting samples, their characterisation, vacuum compatibility and recent improvements will be introduced. Furthermore, the current and future agenda in light of the new project aiming at understanding the actual feasi- bility of the coating for this application in an extreme environment will be discussed. This work is part of the Marie Sklodowska-Curie Training Network EASITrain (European Advanced Superconductivity Innovation and Training), funded by the European Union’s H2020 Framework Programme under grant agreement no. 764879, and now the project ADDENDUM FCC-GOV-CC- 0217 (KE5072/TE) to evaluate Tl (1223) superconducting beam screen coatings for FCC.
Physics, Experiments & Detectors / 83
From vertex to wrapper: the IDEA tracklng system for FCC-ee
Author: Attilio Andreazza1
1 Università degli Studi e INFN Milano (IT)
Corresponding Author: [email protected]
Page 28 FCC Week 2021 / Book of Abstracts
The tracking system of the IDEA detector follows a classical approach for e+e− colliders. Its main tracking device is a large size drift chamber is very light drift chamber exploiting the cluster counting method for particle identification. It is complemented with silicon detectors for the vertex region and for a wrapper around the drift chamber, providing a high precision measurements at theend of the tracking volume. The presentation will discuss the expected performance of the IDEA de- tector concept and recent developments on the use of CMOS pixels for the large volume silicon tracker.
FCC-ee accelerators / 84
FCC-ee positron source
Author: Iryna Chaikovska1
Co-author: WP3 team (FCC-ee injector update studies)
1 CNRS/IJCLab
Corresponding Author: [email protected]
In the framework of the design and realization of a lepton collider, positron sources are essential due to the challenging critical requirements of high-beam intensity and low emittance necessary to achieve high luminosity. In the case of positron beams to be injected into circular colliders, the main concern is an optimized 6D emittance, whereas very high intensities are required for linear colliders. These constraints about intensity and emittance have strong consequences on the heat loadand reliability of the targets. The high-luminosity circular collider FCC-ee will need a low-emittance positron beam with high enough intensity to shorten the injection time. A positron bunch intensity of about 2.1e10 particles is required at the injection into a pre-booster ring. Due to the large 6D production emittance and important thermal load in the production target, the positron injector, in particular the positron source, is one of the key elements of the FCC-ee, requiring special attention. In this framework, we present the preliminary studies of the FCC-ee positron source highlighting the main requirements and constraints.
Plenary session / 85
The FCC-PED Informal Forum of National Contacts
Author: Gregorio Bernardi1
1 APC/LPNHE-Paris CNRS/IN2P3
Corresponding Author: [email protected]
To prepare the Physics/Experiments/Detector aspects of the FCC project, the national contacts (one or two per country) gather regularly to exchange on the progress made in each country, and on how to further increase the collaborative aspects of the project. A short report will be given on the current achievements of the group.
SRF / 86
Beam-cavity interaction challenges for the FCC-ee
Author: Ivan Karpov1
Page 29 FCC Week 2021 / Book of Abstracts
1 CERN
Corresponding Author: [email protected]
The beam-cavity interaction and longitudinal instabilities may affect the choice of theRFsystem for high-current storage rings. In particular, beam loading, higher-order mode power losses, and coupled-bunch instabilities are the main performance limiting factors which must be considered in the early design stage. Operating the FCC-ee at the Z energy will be challenging due to the high beam current and a large number of bunches. In this contribution, the effects are quantified and compared for two different cavity types: 400 MHz single-cell and 600 MHz two-cell slotted waveguide elliptical cavities.
Plenary session / 87
ECFA roadmap for Detector R&D and plans for ECFA workshops on an e+e- Higgs/EW/Top factory
Author: Karl Jakobs1
1 Albert Ludwigs Universitaet Freiburg (DE)
Corresponding Author: [email protected]
Physics, Experiments & Detectors / 88
Global Plans for High Field Magnet R&D
Author: Soren PrestemonNone Corresponding Author: [email protected]
Physics, Experiments & Detectors / 89
FCCAnalysis: tools and algorithms for analysis
Author: Clement Helsens1
1 CERN
Corresponding Author: [email protected]
The FCCAnalysis project provides a declarative analysis framework for EDM4hep based on RDataFrame with high level python interface (PyROOT), access to advanced python tools (e.g. akward array), and object reconstruction codes (e.g. FastJet). A common library of C++ algorithms, including for exam- ple thrust axis minimisation, jet clustering, vertex reconstruction, is being constantly improved for common usage. This talk will review the status and provide some plans for the near andlongterm future.
FCCIS WP5 (Leverage & Engage) / 90
Communicating the FCC feasibility study
Page 30 FCC Week 2021 / Book of Abstracts
Author: Andrea Perez Fernandez1
Co-author: James Gillies 1
1 CERN
Corresponding Authors: [email protected], [email protected]
As mandated by the European Strategy for Particle Physics, CERN has established the Future Circular Collider (FCC) feasibility study to investigate, over the next 5 years, the technical and financial viability of the new generation of particle colliders at CERN. This talk focuses on advances in the development of a local communication plan for the FCCfeasi- bility study. The FCC tunnel would be 3 times longer than that of the Large Hadron Collider (LHC), bringing CERN’s concept of local to another level. This comes with significant consequences. On the one hand, the infrastructure would extend CERN’s local benefits to a much wider area. On the other, some disruption due to activities on the ground, during both the Feasibility Study and in potential subsequent stages of the project, is inevitable. Any action impacting the local area must be communi- cated effectively, through timely engagement with a range of audiences in both Host States. CERN’s communication strategy establishes the for fluid and transparent two-way communication with the local communities. Within this framework, a local communication plan is being developed in close collaboration with local authorities in France and Switzerland. Some of the issues being investigated at the moment are the identification of local stakeholders; the correct use of communi- cation channels; the development of targeted messages and the design of adapted communication supports.
FCCIS WP5 (Leverage & Engage) / 91
What’s new at Overleaf in 2021?
Author: John Hammersley1
1 Overleaf
Corresponding Author: [email protected]
In this presentation I’ll give a summary of the recent feature releases and other new developments at Overleaf. I’ll start with a short overview of the platform itself, before running through the new features and concluding with a look ahead to what’s coming later in the year.
Plenary session / 93
Requirements on FCC-ee from the physics programme
Author: Guy Wilkinson1
1 University of Oxford (GB)
Corresponding Author: [email protected]
Physics motivation is provided for the choice of energy points, and the target integrated luminosities at each, for FCC-ee operation. The possible benefits of four interaction points, rather than two, are assessed. The requirements on the knowledge of the collision energy are presented, together withthe implications for the accelerator. Also discussed are the implications that would arise if a campaign
Page 31 FCC Week 2021 / Book of Abstracts
were to be launched to study s-channel Higgs production. Issues related to the acceptance of the detectors are addressed.
Plenary session / 96
Status of implementation of high-priority Accelerator R&D ini- tiatives
Author: Dave Newbold1
1 STFC Rutherford Appleton Laboratory (GB)
Corresponding Author: [email protected]
Physics, Experiments & Detectors / 97
Physics, Experiments and Detectors pillar: Structure and Objec- tives
Author: Patrick Janot1
1 CERN
Corresponding Author: [email protected]
Physics, Experiments & Detectors / 98
Targets, milestones and progress of Physics Performance
Author: Patrizia Azzi1
1 INFN Padova (IT)
Corresponding Author: [email protected]
FCC-ee accelerators / 99
News on the Q1 magnet prototype’
Author: m Koratzinos1
1 Massachusetts Inst. of Technology (US)
Corresponding Author: [email protected]
A first, single aperture, final focus quadrupole prototype has been designed, constructed andtested at warm. It is a canted cosine theta (CCT) design with the novel feature of eliminating edge effects in field quality. The measurements at warm show that the edge effects correction works beautifully and the overall field quality is excellent with errors not exceeding 0.15 units for all multipoles.
Page 32 FCC Week 2021 / Book of Abstracts
SRF / 101
Baseline & Cavity options for FCC-ee
Author: Franck Peauger1
1 CERN
Corresponding Author: [email protected]
In this talk we will remind the baseline configuration of the SRF system for FCC-ee (booster and collider rings). We will also present new SRF cavity designs like spoke cavities and coaxial resonators, which have been explored recently and compared to the baseline design. A new elliptical 2-cell cavity configuration equipped with slotted waveguides, called SWELL cavity is finally introduced, operating at the intermediate frequency of 600 MHz. This new and innovative SWELL cavity concept has a huge potential to simplify the installation scheme of the overall RF system. The main features and the development plan of the SWELL cavity are presented.
Physics, Experiments & Detectors / 102
Update on Snowmass process & US perspectives incl. EIC
Author: Tor Raubenheimer1
1 SLAC
Corresponding Author: [email protected]
Physics, Experiments & Detectors / 103
Higgs mass and model-independent cross-section studies from the recoil mass
Author: Jan Eysermans1
1 Massachusetts Inst. of Technology (US)
Corresponding Author: [email protected]
In this presentation, the prospects of Higgs mass and model-independent cross-section measure- ments at the FCCee are outlined, using the recoil mass from the ZH Higgstralung process. A base- line analysis with statistical interpretation in the muon channel will be presented and discussed within the targeted experimental conditions such as detector configurations and machine parame- ters.
Physics, Experiments & Detectors / 104
The turnkey software stack Key4hep: status and plans
Author: Frank-Dieter Gaede1
Page 33 FCC Week 2021 / Book of Abstracts
1 Deutsches Elektronen-Synchrotron (DE)
Corresponding Author: [email protected]
Physics, Experiments & Detectors / 105
Jet Flavour tagging at the FCC-ee
Author: Michele Selvaggi1
1 CERN
Corresponding Author: [email protected]
Identification of the flavour of the parton that originated the jet is of paramount importance forthe FCC-ee program. The observables that allow to discriminate between different jet flavours suchas track displacements and time-of-flight are introduced together with the detector design choices that are required to optimally reconstruct such variables. Jet flavour discriminators built on state-of-the- art Machine Learning (ML) techniques using graph-based neutral networks are then described, and the impact of different detector design assumptions on the performance is discussed. The application on the measurement of the charm and strange yukawa is then briefly discussed.
Physics, Experiments & Detectors / 106
FCCSW: status and (users) workflows
Author: Valentin Volkl1
1 CERN
Corresponding Author: [email protected]
Physics, Experiments & Detectors / 107
Probing heavy new physics systematically at FCC
Author: Gauthier Durieux1
1 CERN
Corresponding Author: [email protected]
FCCIS WP3 (Integrate Europe) / 112
Excavation materials management plan: progress and ongoing work
Author: LAETITA D’ALOIA1
1 CETU
Page 34 FCC Week 2021 / Book of Abstracts
Corresponding Author: [email protected]
FCCIS WP3 (Integrate Europe) / 113
Host states processes: Update and next steps
Author: Maude SauvainNone Corresponding Author: [email protected]
FCCIS WP5 (Leverage & Engage) / 115
From collaboration to submission
Author: Katherine Arundell1
1 Springer Nature
Corresponding Author: [email protected]
FCCIS WP5 (Leverage & Engage) / 116
Round table discussion
FCC-hh accelerator / 118
Modifications of injection and beam dump systems for new col- lider layout
Author: Wolfgang Bartmann1
1 CERN
Corresponding Author: [email protected]
FCCIS WP5 (Leverage & Engage) / 119
FCCIS scientific meetings and publication status
Author: Marcin Chrzaszcz1
1 Polish Academy of Sciences (PL)
Corresponding Author: [email protected]
Page 35 FCC Week 2021 / Book of Abstracts
FCCIS WP5 (Leverage & Engage) / 120
FCC Communication Strategy
Author: Markus MooslechnerNone Corresponding Author: [email protected]
FCC-ee accelerators / 123
FCC-ee upgrade to muon collider
Author: Daniel Schulte1
1 CERN
Corresponding Author: [email protected]
A new muon collider collaboration is forming with the aim to develop this unique concept for a very high energy lepton collider. The presentation will introduce the collider and its challenges. Itwill also comment on options to use the FCC infrastructure for this purpose.
SRF / 124
Overview of Multilayer Developments at Jlab
Author: Anne-Marie Valente-Feliciano1
1 Jefferson Lab
Corresponding Author: [email protected]
Summaries / 125
Accelerator summary
Authors: Frank Zimmermann1; Ilya Agapov2
1 CERN 2 Deutsches Elektronen-Synchrotron (DE)
Corresponding Authors: [email protected], [email protected]
Summaries / 126
Technologies summary
Author: Roberto Losito1
1 CERN
Page 36 FCC Week 2021 / Book of Abstracts
Corresponding Author: [email protected]
Summaries / 127
Summary of FCCIS work packages 3, 4 and 5
Author: Johannes Gutleber1
1 CERN
Corresponding Author: [email protected]
Summaries / 128
Technical Infrastructure and Civil Engineering summary
Author: Klaus Hanke1
1 CERN
Corresponding Author: [email protected]
Summaries / 129
Physics, Experiments and Detectors summary
Author: Alain Blondel1
1 Universite de Geneve (CH)
Corresponding Author: [email protected]
Summaries / 130
Closing remarks
Author: Frank Zimmermann1
1 CERN
Corresponding Author: [email protected]
Physics, Experiments & Detectors / 131
Detector challenges, towards detector concepts at FCC-ee
Author: Paolo Giacomelli1
Page 37 FCC Week 2021 / Book of Abstracts
1 Universita e INFN, Bologna (IT)
Corresponding Author: [email protected]
SRF / 132
Overview of the EIC RF system and synergies with FCC-ee
Author: Robert Alan RimmerNone
Corresponding Author: [email protected]
The EIC, a new collider that will be constructed at Brookhaven National Laboratory in partnership with Jefferson Lab, comprises an ion storage ring based on RHIC and an all new electron storage ring. Polarized ions are provided by an upgraded RHIC injector chain while electrons are provided by a new polarized source, linac and rapid cycling synchrotron. Luminosity will be maintained by frequent bunch swap out of electrons and high energy electron cooling of the ions. A number of challenging RF systems will be needed including high-current storage ring bunching and crab- bing cavities, a high current ERL for the cooler and acceleration and bunch splitting systems for the hadron beam formation. Many challenges are shared with FCC-ee and synergies and areas for fruitful collaboration are highlighted.
FCC-eh / 133
Status of heavy neutrino searches at ep colliders
Author: Ahmed HammadNone
Co-authors: Fischer Oliver 1; Stefan Antusch 2
1 Liverpool 2 Basel University
Corresponding Author: [email protected]
The extension of the SM of particle physics by sterile neutrinos explains the smallness ofneutrino masses as observed by the neutrino oscillation experiment. Since the mass scale of the sterile neu- trinos is unconstrained, it is useful to discuss experimental motivated predictions for specific mass scale. Sterile neutrinos can be tested at particle colliders in three different mass ranges MN < MW, where the sterile neutrinos can be long lived and can be tested via its displaced distance. MN ~ EW scale; around this mass scale the sterile neutrinos can be tested via lepton number or lepton flavor violation processes. MN > O(TeV); sterile neutrinos can be tested indirectly via its contribution to loop processes, e.g. Z -> mu e, mu-> 3e, etc. In this talk, we investigate the sensitivity of the proposed Large Hadron Electron collider (LHeC) and the Future Circular Collider (FCCeh) to sterile neutrino searches for the three mass scales.
Physics, Experiments & Detectors / 134
Recent developments on scintillator materials for calorimetry
Author: Etiennette Auffray1
1 CERN
Page 38 FCC Week 2021 / Book of Abstracts
Corresponding Author: [email protected]
Since many decades scintillating crystals have been used for high resolution electromagnetic calorime- ters and significant progress has been made since 30 years in the field of inorganic scintillators inthe understanding of their scintillation properties, radiation hardness and production methods. In recent years many studies have been carried out in the framework of the Crystal Clear Collaboration on the investigation, improvement and exploitation of different processes for new fast light emission such as wideband semiconductor nanomaterials, hot intraband luminescence, cross luminescence and Cerenkov light, as well as on the production and the assembly of such material: crystal fibers, 3D printing, Ceramic, hybrid structure combining materials with different properties. Selected results of the recent research efforts and developments on scintilllators for future detectors will be presented.
Technical infrastuctures / 138
Integration of the FCC
Authors: Jean-Pierre Corso1; Fani Valchkova-Georgieva2
1 CERN 2 Bulgarian Academy of Sciences (BG)
Corresponding Author: [email protected]
this presentation will show all integration studies done until now, and the forthcoming studies https://edms.cern.ch/file/2599317/1/FCC_Week_Integration_Abstract_FV_JPC.pptx
EASITrain / 139
Turbocompressor test facility operating with Nelium mixtures and heat transfer effects
Authors: Damian M. Vogt1; Maxime Pierre Podeur1
1 University of Stuttgart
Corresponding Author: [email protected]
Within the framework of the Future Circular Collider (FCC) and the EASITrain project, a major revision of the entire cryogenic cycle for the new machine is investigated in comparison to the LHC architecture. In particular, a closed-loop cryogenic cycle relying on turbocompressors and operating with Nelium mixtures is foreseen to enable the pre-cooling of helium. To better understand the challenges and opportunities associated with the design and operation of radial compressors with such light gases, a closed loop test facility has been designed, built and commissioned at the ITSM (University of Stuttgart). The test facility has been developed to operate with air as well as with helium-neon gas mixtures of varying mixing ratios. In this presentation, an overview of the test facility is first presented with its architecture, the com- ponents used together with a description of the operating procedure. Experimental results are then provided and validated against numerical evaluations. Moreover, the compressor motor being liq- uid cooled, a heat transfer between the coolant and the operating fluid leads to a modification of the operating fluid temperature and with it the measured aerodynamic efficiency. A model validfor all operating points and gases has been developed to remove this effect from measurements and is introduced here.
Page 39 FCC Week 2021 / Book of Abstracts
Technical infrastuctures / 140
Safety for the FCC Feasibility Study
Author: Thomas Otto1 Co-authors: Andre Henriques 1; Ghislain Roy 1; Markus Widorski 1; Oriol Rios 1
1 CERN
Corresponding Author: [email protected]
Safety for the FCC feasibility study comprises occupational health and safety, radiation protection, beam safety and personnel protection systems, fire safety and emergency response and environmen- tal monitoring. In a comprehensive safety report, we will document hazards and risks of the technologies employed in FCC, and make recommendations for mitigation measures. In many cases, these will be “standard best practice” from previous experience or regulatory obligations. For the unprecedented challenges to safety by FCC, we propopse a “Safety by Design” approach, systematically reducing the exposure of personnel to risk. The Safety Working Group will collaborate closely with other WGs in Technical Infrastructures and project-wide.
EASITrain / 141
Electro-hydraulic forming of SRF cavities: Effect of strain rate on niobium single crystals
Author: Jean Francois CroteauNone Co-authors: Eureka Pai Kulyadi 1; Leonardo Agudo Jácome 2; Chaitanya Kale 3; Elisa García-Tabarés Valdivieso 4; Anita T. Perez Fontenla 4; Derek Siu 5; Di Kang 1; Philip Eisenlohr 1; Thomas R. Bieler 1; Kiran N. Solanki 3; Anna M. Manzoni 2; Said Atieh 4; Daniel Balint 5; Paul Hooper 5; Nicolas Jacques 6; Elisa Cantergiani 7
1 Michigan State University 2 Bundesanstalt für Materialforschung und -prüfung 3 Arizona State University 4 CERN 5 Imperial College London 6 École Nationale Supérieure de Techniques Avancées Bretagne 7 I-Cube Research/Bmax
Corresponding Author: [email protected]
An investigation of the dislocation substructure and mechanical properties of high-purity niobium single crystals with different initial crystal orientations deformed in tension at strain rates of10^{- 4} to 10^3 s^{-1} is presented. Specimens were cut from a large grain niobium disk used for the manufacturing of SRF cavities. Different crystallographic tensile directions exhibited significantly different softening and hardening behaviors and elongation at fracture. Such anisotropy isreduced at high strain rates. Also, different dislocation substructures were observed with TEM at low and high strain rates. At low strain rates, dislocation cells with a high density of long dislocations were observed. At high strain rates, homogeneously distributed dislocations with a higher dislocation dipole density were observed. The relationship between the differences in dislocation substructures and mechanical properties at low and high strain rates and the potential effects on the supercon- ducting properties are discussed.
Page 40 FCC Week 2021 / Book of Abstracts
FCC-ee accelerators / 142
Top up injection - Status and next steps
Author: Masamitsu Aiba1
1 Paul Scherrer Institut (CH)
Corresponding Author: [email protected]
Top-up operation is essential for FCC-ee to maximize the integrated luminosity. Numerous con- straints and requirements have to be met: limited dynamic aperture, transparency of the injection process, compatibility with four operation modes, reliability, availability, machine protection, etc. This presentation first summarizes the status of the design study, and then important next stepsare discussed. In addition, another option for the injection septum is proposed. We assumed two types of septa in early studies, i.e., ordinary thick septum and extremely thin septum. These options have pros and cons, and the third option can be a good compromise.
SRF / 144
FPC challenges and perspectives for FCC-ee
Author: Eric Montesinos1
1 CERN
Corresponding Author: [email protected]
Overview of the various challenges regarding the construction of very high power Fundamental Power Couplers will be presented.
FCC-eh / 145
LHeC and FCC-eh detector status
Author: Alessandro Polini1
1 Universita e INFN, Bologna (IT)
Corresponding Author: [email protected]
The physics programmes at the LHeC and the FCC-eh require a general purpose detector with large acceptance and with high resolution tracking and calorimetry plus forward and backward detectors. Following the evolving physics requirements, machine constraints and the development of detector technology, an update of the detector and its subcomponents is presented and discussed.
Civil Engineering / 146
3D geological modelling and subsurface uncertainties quantifica- tion to guide the optimal FCC placement
Author: Andrea Moscariello1
Page 41 FCC Week 2021 / Book of Abstracts
1 UNIGE
Corresponding Author: [email protected]
Technology R&D / 148
Design Studies and HiRadMat test for the FCC-ee Beam Dump System
Author: Alexander Krainer1
Co-authors: Anton Lechner 1; Wolfgang Bartmann 1; Francois-Xavier Nuiry 1; Salim Ogur 2; Antonio Perillo Marcone 1
1 CERN 2 CNRS/IJCLab
Corresponding Author: [email protected]
The FCC-ee operation modes foresee stored beam energies of up to 20 MJ (for Z operation). Inthis talk an optimized beam dumping system is presented. This system utilizes passive beam diluters (Spoilers) and therefore eliminates any active dilution failure scenarios, while also being capable of shortening the dump line to about 350 m from extraction. Materials for this Spoilers have been studied extensively and key material properties have been iden- tified using both FLUKA and LS-Dyna simulations. In a HiRadMat experiment, scheduled forOcto- ber 2021, these findings will be tested using scaled prototypes of the proposed Spoilers with special beam optics and pre-targets to reach similar mechanical stresses as seen in the simulations.
Plenary session / 149
Opening, CERN vision and plans until 2025
Author: Fabiola Gianotti1
1 CERN
Corresponding Author: [email protected]
Civil Engineering / 150
Civil Engineering assessment of placement scenarios by ILF Con- sulting
Author: Werner Dallapiazza1
1 ILF Zurich
Corresponding Author: [email protected]
Summaries / 151
Page 42 FCC Week 2021 / Book of Abstracts
SRF summary
Authors: Frank Gerigk1; Olivier Brunner1
1 CERN
Corresponding Authors: [email protected], [email protected]
FCC-ee accelerators / 152
ERL-based e+e- collider
Author: Vladimir LitvinenkoNone Corresponding Author: [email protected]
We presenting recent development of concept for future the energy-efficient ERL-based high-energy high-luminosity e+e- collider. This collider can be placed in 100 km tunnel for future FCC and collide highly polarized electron and position beam with c.m. energy up to 600 GeV.
Civil Engineering / 153
Civil Engineering Status and Plans
Authors: Alexandra TudoraNone; John Andrew Osborne1
1 CERN
Corresponding Author: [email protected]
This presentation will give a status update on the civil engineering feasibility studies sincethecon- ceptual design phase. To achieve the objectives of the next ESPPU and to deliver a comprehensive feasibility study report, CERN’s civil engineering team have embarked in the first phase of the site investigations campaign, in the so-called High-Risk Areas. This talk will summarize the evolution of the FCC tunnel alignment and the process of identifying critical areas where SI are required to reduce the uncertainty in the ground conditions and to minimize the underground risks.
Technology R&D / 154
Some experiences with the vacuum system in SuperKEKB
Author: Yusuke Suetsugu1
1 KEK
Corresponding Author: [email protected]
The SuperKEKB, the upgrade project of KEKB, is an electron-positron collider with asymmetric en- ergies, that is, 7 GeV electrons and 4 GeV positrons. The construction started in 2010 and ended in 2016. Following the test operation (Phase-1) and the commissioning operation (Phase-2), the physics operation (Phase-3) has started since 2019. As for the vacuum system, most of the vacuum components, especially in the positron ring, were newly fabricated to especially manage the electron cloud effect (ECE), and to reduce beam impedance. Most of new beam pipes basically have two antechambers at both sides of a central beam channel.
Page 43 FCC Week 2021 / Book of Abstracts
The main pump at arc sections of the ring is a strip-type NEG installed in one of the antechambers. New bellows chambers and gate valves have basically a comb-type RF-shield and have the same cross sections to the connecting beam pipes. Countermeasures against the ECE, such as the coating of TiN film, the grooved surface, the clearing electrode and so on, were adopted for the positron ring.The MO-type flanges, which have structurally little step inside, were adopted to the connection flanges between the beam pipes and the bellows chambers. The physics operation has been continuing steadily gradually increasing the performance. The world-highest peak luminosity of 3.12E34 /cm^2/s has been achieved by June, 2021. Typical stored beam currents during the physics operation are approximately 800 mA and 700 mA for the positron and electron rings, respectively. The vacuum scrubbing of beam pipes is also processing steadily. The pressure rises per unit beam current are now approximately 1E-7 Pa/A and 2E-8 Pa/Aforthe positron and electron ring, respectively. The bellows chambers and gate valves with a comb-type RF-shield, and the MO-type flanges have been working almost as expected up to now, that is,no indication of discharge and over-heating has not been observed. The effect of antechambers and TiN coating on the suppression of ECE was confirmed, although additional external magnetic fields were required to suppress the ECE finally. One annoying problem was frequent beam losses accom- panied by pressure bursts mainly observed in the positron ring during Phase-1, which were probably caused by collisions of the beam with dusts. Recently, very rapid (20~30 micro second = 2-3 turns) beam losses have been observed sometimes accompanied with pressure bursts, but the cause has not been clarified yet and the investigation is ongoing. Here presented are the brief introduction of the vacuum system in SuperKEKB, and the major achievements and problems obtained in the beam operations so far.
Technology R&D / 155
Longitudinal bunch-by-bunch profile measurements at KARA based on EO sampling & developments for FCC
Author: Gudrun Niehues1
1 Karlsruhe Institute of Technology
Corresponding Author: [email protected]
At the KIT the world’s first electro-optical (EO) near-field monitor for a high bunch-repetition stor- age ring, the Karlsruhe Research Accelerator (KARA), was developed and is installed to detect lon- gitudinal electron bunch profiles. Imprinting the longitudinal profiles onto chirped laser pulses and using the ultra-fast line-camera KALYPSO built at KIT, single-shot bunch-by-bunch measurements are achieved. Recently, we demonstrated tomographic imaging of the 2D longitudinal phase space distribution of the electron bunches at MHz-repetition rate within 61 µs. EO near-field diagnostics are a part of the distributed sensor network at KARA. Testing prototype diagnostics at KARA addresses challenges like high repetition rates, different bunch lengths and charges, which will play an important role for diagnostics at the FCC. This talk will give an overview of achieved results and developments for future applications atthe FCC.
CERN Courier webinar / 157
Status and scope of the FCC Innovation Study
Author: Michael Benedikt1
1 CERN
Corresponding Author: [email protected]
Page 44 FCC Week 2021 / Book of Abstracts
CERN Courier webinar / 158
How the Higgs boson opens a new window on fundamental physics?
Author: Beate Heinemann1
1 DESY and University of Freiburg (Germany)
Corresponding Author: [email protected]
CERN Courier webinar / 159
Potential of a future circular collider to address the dark sector of the universe
Author: Matthew Philip Mccullough1
1 CERN
Corresponding Author: [email protected]
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