HE-LHC: The High-Energy Large Hadron Collider Future Circular Collider Conceptual Design Report Volume 4

In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries.

FCC-hh: The Hadron Collider: Future Circular Collider Conceptual Design Report Volume 3

José Luis Abelleira Fernández, Bernhard Auchmann, Sandra Aumon, Fabio Avino, Javier Barranco Garcia, Manuel Bauer, Luca Bottura, Pierluigi Bruzzone, Xavier Buffat, Francesco Cerutti, Agnieszka Chmielinska, Roberto Contino, Marco Drewes, Sondre Vik Furuseth, Massimo Giovannozzi, Patrik Gonçalves Jorge, Elena Graverini, Alexej Grudiev, Ruchi Gupta, Doohyun Kim, Mathias Oleg Knecht, Mithlesh Kumar, Lotta Maria Mether, Giuseppe Montenero, Tatiana Pieloni, Leonid Rivkin, François Robert, Luca Rossi, Jean-Michel Sallese, Alexandra Sarabando de Carvalho, Michael Schenk, Rudiger Schmidt, Jan Steggemann, Alban Sublet, Claudia Tambasco, Sofia Vallecorsa, Martin Vogel, Rui Wang, Jorg Wenninger, Andrea Wulzer, Yi Zhang, Hua Zhang, Frank Zimmermann

In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100TeV. Its unprecedented centre of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries.

2019

FCC-ee: The Lepton Collider: Future Circular Collider Conceptual Design Report Volume 2

In response to the 2013 Update of the European Strategy for Particle Physics, the Future Circular Collider (FCC) study was launched, as an international collaboration hosted by CERN. This study covers a highest-luminosity high-energy lepton collider (FCC-ee) and an energy-frontier hadron collider (FCC-hh), which could, successively, be installed in the same 100 km tunnel. The scientific capabilities of the integrated FCC programme would serve the worldwide community throughout the 21st century. The FCC study also investigates an LHC energy upgrade, using FCC-hh technology. This document constitutes the second volume of the FCC Conceptual Design Report, devoted to the electron-positron collider FCC-ee. After summarizing the physics discovery opportunities, it presents the accelerator design, performance reach, a staged operation scenario, the underlying technologies, civil engineering, technical infrastructure, and an implementation plan. FCC-ee can be built with today's technology. Most of the FCC-ee infrastructure could be reused for FCC-hh. Combining concepts from past and present lepton colliders and adding a few novel elements, the FCC-ee design promises outstandingly high luminosity. This will make the FCC-ee a unique precision instrument to study the heaviest known particles (Z, W and H bosons and the top quark), offering great direct and indirect sensitivity to new physics.

2019

Electron cloud studies for the LHC and future proton colliders

César Octavio Domínguez Sánchez De La Blanca

The Large Hadron Collider (LHC) is the world’s largest and most powerful particle collider. Its main objectives are to explore the validity of the standard model of particle physics and to look for new physics beyond it, at unprecedented collision energies and rates. A good luminosity performance is imperative to attain these goals. In the last stage of the LHC commissioning (2011-2012), the limiting factor to achieving the design bunch spacing of 25 ns has been the electron cloud effects. The electron cloud is also expected to be the most important luminosity limitation after the first Long Shut-Down of the LHC (LS1), when the machine should be operated at higher energy and with 25-ns spacing, as well as for the planned luminosity upgrade (HL-LHC) and future high energy proton colliders (HE-LHC and VHE-LHC). This thesis contributes to the understanding of the electron cloud observations during the first run of the LHC (2010-2012), presents the first beam dynamics analysis for the next generation of high energy hadron colliders, and assists in the prediction of how electron clouds will impact the performance of the future high-luminosity and high-energy machines. In particular, the thesis discusses a method to benchmark pressure measurements at the LHC against electron cloud build-up simulations for identifying the most relevant surface parameters. This method allowed monitoring the effectiveness of LHC “scrubbing runs”, revealing that in the warm regions, the maximum Secondary Electron Yield, δmax, decreased from an initial value of about 1.9 down to about 1.2 (with a low-energy electron reflectivity R ≈ 0.3), thanks to surface conditioning. In addition, the “map formalism”, a good approximation to quickly explain and predict electron cloud effects, has been further developed and applied, for the first time, to optimize the scrubbing process at the LHC. For the HL-LHC, several novel filling schemes have been analyzed in terms of luminosity performance and electron cloud activity. Only a few of them are compatible with an electron cloud activity lower than for the baseline scenario. We highlight a promising option which could be a good fallback scenario in case the electron cloud effects prevent the injection of the baseline beam. This option could also be considered for the nominal LHC after the LS1 if electron cloud turns out to be a serious obstacle. Regarding the future high-energy proton colliders (HE- and VHE-LHC), in the frame of this thesis a performance model was developed to predict the luminosity as a function of time and to optimize the beam parameters, carrying out the first ever performance analysis for these machines. Several scenarios have been considered, including round and flat beams as well as different bunch spacings. The parameters presented in this thesis have been submitted as an input for the most recent update of the European Strategy for Particle Physics. Finally, we also report the electron cloud studies performed for both high energy machines. The large amount of primary photoelectrons generated by synchrotron radiation at these high energies motivates the consideration of high efficiency photon stops as well as other mitigation techniques (e.g. a-C coatings and clearing electrodes). Although for both machines (HE- and VHE-LHC) a tentative bunch spacing of 25 ns has been considered as baseline assumption, the results of this thesis suggest the possibility of going down to 5 ns, since such a beam would present several advantages.

EPFL2013

Electron cloud studies for the LHC and future proton colliders

César Octavio Domínguez Sánchez De La Blanca

EPFL2013