Conveners
FCC-ee accelerators: FCCIS WP2
- Tor Raubenheimer (SLAC National Accelerator Laboratory (US))
FCC-ee accelerators: FCCIS WP2
- Michiko Minty
FCC-ee accelerators: EPOL
- Eliana Gianfelice
FCC-ee accelerators: FCC-ee - 1 correction, stability, alignment, parameters
- Angeles Faus-Golfe (IJClab IN2P3 CNRS-Université Paris-Saclay (FR))
FCC-ee accelerators: FCC-ee - 2 code development & modelling
- Felix Simon Carlier (EPFL)
FCC-ee accelerators: EPOL 2
- Ferdinand Willeke (Brookhaven Natl LAb)
FCC-ee accelerators: MDI (Machine Detector Interface)
- Maria Chamizo Llatas (Brookhaven National Laboratory (US))
FCC-ee accelerators: MDI (Machine Detector Interface)
- Katsunobu Oide (High Energy Accelerator Research Organization (JP))
Since the last FCC Week conference, the layout of the FCC tunnel has been further optimized to provide a more favourable placement in the Geneva Basin.
Compared to the layout used in the Conceptual Design Report, the new tunnel layout now features a slightly smaller circumference of 91 km, but is compatible with four experimental insertions.
In this presentation, we present the latest...
In order to achieve its ultra-low vertical emittance (1 pm) and high luminosity (of up to $230 \times 10^{34}$~cm$^{-2}$~s$^{-1}$ per collision point), the e$^+$e$^-$ Future Circular Collider (FCC-ee) requires a well-informed alignment strategy, powerful correction methods, and good understanding of the impact of vibrations. The large ring size, high natural chromaticity, small $\beta^*$, and...
In order to maximize the integrated luminosity of the FCC-ee, top-up injection will be employed. The positron and electron beams will be accelerated to the collision energy in the booster ring before being injected into the collider ring where it will merge with the stored beam. Regular injection maintains an effectively constant beam current and, other than a brief period during the injection...
Collective effects due to the high beam intensities in FCC-ee, in particular for the Z-pole configuration, are very important for reaching the design performance. While resistive wall represents a major source of impedance for such a large machine, also other contributions, such as that of the bellows with included RF fingers, cannot be neglected. We have studied the single beam instabilities...
Collective effects are very important for the FCC-ee collider due to very extreme parameters, such as the high beam current. Taking into account the updated impedance model, new results of beam dynamics simulations for FCC-ee will be presented. We will analyse the longitudinal microwave instability threshold studying bunch length and energy spread versus beam current, and TMCI, transverse mode...
In this work, we present updates on the electron cloud build-up studies considering various sections of the FCC-ee. Additionally, we report arc dipole & drift regions using the new baseline beam parameters for four IPs. Furthermore, estimated threshold central electron densities for the single-bunch instability are included. The electron density at the center of the beam pipe for 30 ns and 32...
The recent measurement of the W mass by the CDF collaboration at the Tevatron in hadron collisions has created a significant buzz in the community. Quite apart from the fact that it disagrees significantly both with the Standard Model predictions and with previous measurements of this quantity, this result is remarkable by two aspects:
- the systematic error is of the same size as the...
The Future Circular electron-positron Collider, FCC-ee, is designed for unprecedented precision for particle physics experiments from the Z-pole to above the top pair threshold. This demands a precise knowledge of the center-of-mass energy (ECM) and collision boosts at all four interaction points.
Synchrotron radiation losses range from 40 MeV per turn at the Z-pole with 45.6 GeV beam energy,...
Precise energy calibration is a key tool for the FCC-ee physics programme and will be obtained by resonant depolarization. It requires the implementation of a Compton polarimeter with unprecedented performance. The presentation is mainly devoted to the description of the foreseen laser performance and the associated challenges.
Very high luminosities at the production poles (z,w,h,t) of FCC-ee are planned at the four Interaction Points (IP); thus very low beta star values are required at the IP, implying the use of very strong quadrupoles. Concurrently, LAPP work has underlined the strong correlation between the vibrations of the quadrupoles due to ground motion amplified by the dynamics of the cryostat in cantilever...
This presentation will briefly talk about error propagation in alignment networks in tunnels. It will also give a summary of alignment experiences that were reported at the FCC-ee optics tuning and alignment mini-workshop. Finally the presentation will show some results from SLAC in particular and the importance of alternate measurement methods added to conventional laser tracker and leveling...
The presentation will show the techniques developed to perform commissioning-like simulations for the ESRF-EBS upgrade. In particular alignment specifications are updated respect to the past. Instead of specifying girder-to-girder errors, simulated surveys of the storage ring were used, providing a more complete and simple to use information. Also, the relative impact of different magnet...
The aim for the highest luminosities with the FCC-ee poses several constraints on the choice of the machine parameters. Unprecedented conditions are foreseen during beam-beam collisions which are expected to give rise to previously unseen dynamical mechanisms. The exploration and understanding of these effects as well as the identification of optimal working points are of crucial importance...
The talk presents the status of MAD-X code and recent developments related in particular to FCC-ee studies.
A conceptual design for a collimation system in the FCC-ee is currently under preparation. The current focus is the design of a betatron and off-momentum collimation system, housed in a single insertion. The latest collimation configuration under study is presented. The development of collimation simulation frameworks for the FCC-ee is covered. The frameworks are based on a coupling between a...
Two possible scenarios for measuring the frequency of spin precession in FCC-ee storage rings at the threshold of the birth of Z and WW-pairs are discussed. One of the scenarios involves the use of the well-known method of Resonant Depolarization of pilot bunches of the pre-polarized particles. While in the second approach it is proposed to use a powerful short-pulse RF magnet (flipper) to...
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 polarization, and crossing scheme. An overview of the MDI design will be presented with a picture of the recent updates in the layout and ongoing studies. The status of the MDI activity will be summarised...
This presentation is about the modelling process for vibrations estimations used at LAPP (Annecy's particle physics laboratory) for the FCC project. The main goal of this work is to be able to predict the magnets displacements knowing only the ground displacements. The presentation explains the connection between mechanical calculations and optics studies. It also describes the different steps...
The precise alignment and monitoring of the FCC-ee MDI is mandatory in order to reach the designed luminosity. Though, the extremely elegant but also complex MDI design raises some tough challenges.
This presentation will underline the different challenges and explain why they represent difficulties for the design of an alignment and monitoring system. Subjects such as design, technology,...
A status update on the beam induced backgrounds studies in the FCC-ee MDI region is presented. Currently under study are the optimisation of the Synchrotron Radiation (SR) shieldings, and background in the detector caused by Incoherent Pair Production (ICP) and beam particles lost during tracking. The turnkey software Key4HEP is being used to track the background particles in the CLD detector...
The interaction region for the Future Circular Collider FCC-ee at 182.5 GeV is a sensitive section of the accelerator. The synchrotron radiation produced in the surrounding environmnent of the detector can result in background or damages to the hardware. The studies will present the deposited synchrotron radiation power from the magnetic elements included in the interaction region as well as...
