30 Works

Glossary and definitions

The Editorial Team
No abstract.

Vacuum system

V. Baglin, P. Chiggiato, C. Garion & G. Riddone
The luminosity upgrade programme (HL-LHC) requires modifications of the present LHC’s vacuum system, in particular in the triplets, crab cavities, matching section and experimental areas. Such modifications must follow guidelines similar to those followed for the present machine. The increased stored current implies a higher thermal power in the beam screen from the image current moving along with the stored particles and stronger synchrotron radiation (SR) and electron cloud (EC) effects, which in turn translate...

Collimation system

S. Redaelli, R. Bruce, A. Lechner & A. Mereghetti
A variety of processes can cause unavoidable beam losses during normal and abnormal beam operation. Because of the high stored energy of about 700 MJ and the small transverse beam sizes, the HL-LHC beams are highly destructive. Even a local beam loss of a tiny fraction of the full beam in a superconducting magnet could cause a quench, and larger beam losses could cause damage to accelerator components. Therefore, all beam losses must be tightly...

Impact of radiation on electronics and opto-electronics

M. Backhaus, M. Bindi, P. Butti, E. Butz, E. Chabert, S. Chen, J. Dickinson, W. Erdmann, J. Garcia Pascual, R. Gerosa, B. Haney, H. Hillemanns, K. Lantzsch, A. La Rosa, K. Padeken, F. Pinto, G. Pownall, D. Robinson, A. Rozanov, J. Troska & T. Weidberg
In this chapter we will present the results of the impact of radiation on electronics and opto-electronics for two of the LHC experiments during Run 1 and Run 2. ATLAS results are presented in Section 6.1; CMS in Section 6.2. In Section 6.3 we will present a comparison between the two experiments, highlighting operational guidelines and proposing solutions to build the electronics and opto-electronics of the future LHC experiments.

Simulating radiation effects and signal response in silicon sensors

M. Benoit, M. Bomben, E. Chabert, T. Lari, J. Llorente Merino, B. Nachman, L. Rossini, P. Sabatini, J. Sonneveld, C. Suarez, M. Swartz, T. Szumlak & A. Wang
Simulating the effects of radiation on signal response in silicon sensors is crucial for accurately predicting detector performance throughout the lifetime of the experiment. This, in turn, improves the reconstruction accuracy of proton–proton collisions and helps maintain the experiment’s physics reach. In what follows, the strategies implemented by the LHC experiments to correctly simulate the evolution of silicon tracking performance with luminosity will be presented. Different implementations of sensor simulations are used by the large...

Collider-experiment interface

F. Sanchez Galan, H. Burkhardt, F. Cerrutti, A. Gaddi, J.L. Grenard, L. Krzempek, M. Lino Diogo Dos Santos, J. Perez Espinos, M. Raymond & P. Santos Diaz
The HL-LHC targeted luminosities for the four main experiments will require upgrades of multiple subsystems in In particular, the LHCb experiment subsystems as the vertex locator (VELO), the ring-imaging Cherenkov (RICH) detectors and the tracking system will undergo a major upgrade in LS2, and its surrounding protection systems will be upgraded with neutral absorbers (TANB) to allow to reach the HL-LHC foreseen peak luminosity as from Run 3. Also, in LS2, ALICE will replace its...

List of machine and beam parameters

The Editorial Team
No abstract.

Overview of radiation effects on detector systems

I. Dawson, F. Faccio, M. Moll & A. Weidberg
In this section we give an overview of the effects of radiation on silicon detector systems in the LHC experiments. We divide the sections into: sensors; electronics; optoelectronics; services. While the physics of the energy loss between these categories is similar, the radiation quantities of interest used to evaluate damage are usually different. As an example, sensor radiation studies typically focus on the effects of bulk displacement damage, whereas degradation in electronics is generally more...

The LHC machine and experiments

A. Alici, M. Bomben, I. Dawson & J. Sonneveld
The Large Hadron Collider is a 26.7 km circular accelerator based on a twin aperture superconducting magnet design with a design proton beam energy of 7 TeV. The four particle physics experiments ALICE, ATLAS, CMS, and LHCb are located around the ring. The LHC was first operated with beams for short periods in 2008 and 2009. In 2010, a first experience with the machine was gained at a beam energy of 3.5 TeV, with moderate...

Safety

T. Otto, C. Adorisio, C. Gaignant, A. Infantino & M. Maietta
CERN declares in its safety policy that it will ensure the best possible protection in health and safety matters of all persons participating in the Organization’s activities or present on its site, as well as of the population living in the vicinity of its installations, limit the impact of the Organization’s activities on the environment, and guarantee the use of best practice in matters of safety. A safety organisation accompanies the life cycle of every...

Energy deposition and radiation to electronics

F. Cerutti, R. Garcia Alia, G. Lerner, M. Sabaté Gilarte & A. Tsinganis
Proton–proton inelastic collisions taking place inside the four LHC detectors generate a large number of secondary particles with an average multiplicity of approximately 120 per single proton–proton interaction with 7 TeV beams, but with very substantial fluctuations over different events. Moving away from the interaction point (IP), this multiform population evolves, even before touching the surrounding material, because of the decay of unstable particles (in particular neutral pions decaying into photon pairs).

Beam injection and dumping systems

C. Bracco, M.J. Barnes & A. Lechner
The beam transfer into the LHC is achieved by the two transfer lines TI2 and TI8, together with the septum and injection kickers, plus associated systems to ensure the protection of the LHC elements in case of a mis- steered beam. The foreseen increase in injected intensity and brightness for the HL-LHC means that the protection functionality of the beam-intercepting devices (TDI) needs upgrading. In addition, the higher beam current significantly increases the beam-induced power...

Conclusions

I. Dawson
The LHC experiments have been running successfully and taking data since 2010. Much experience has been gained in running detector systems in challenging radiation conditions, and the impact on operation and performance has been assessed in this report. In general, we find the impact of the radiation effects to be in accordance with initial design expectations. While some unexpected effects have been observed with challenging consequences, these were in general successfully mitigated against.

Simulation of radiation environments

A. Alici, I. Azhgirey, I. Dawson, M. Huhtinen, V. Ivantchenko, D. Kar, M. Karacson, S. Mallows, T. Manousos, I. Mandić, A. Di Mauro, S. Menke, P.S. Miyagawa, A. Oblakowska-Mucha, S. Pospisil, T. Szumlak & V. Vlachoudis
Simulating radiation environments is crucial in the design phase of new hadron collider experiments or upgrades, especially when extrapolating to new centre of mass collision energies where previous experience cannot be relied on. The generation of radiation fields in the LHC experiments is dominated by proton–proton collisions, with contributions from beam-gas interactions and other machine losses. It is therefore essential to first reproduce the proton–proton collisions, using Monte Carlo event generators such as PYTHIA8 and...

11 T dipole and new connection cryostat for the dispersion suppressor collimators

F. Savary & D. Schörling
In Run 3 the intensity of the ion beams (usually Pb ions) for ion–ion collisions is planned to be increased by a factor of three: from 40 × 109 to 120 × 109 circulating particles. This intensity increase will amplify the losses in the cold zone at P2 and P7 and may drive the beam induced heat losses in the main dipoles in the dispersion suppressor (DS) region above the quench limit. To avoid limiting...

Cryogenics for the HL-LHC

S. Claudet, G. Ferlin, E. Monneret, A. Perin, O. Pirotte, M. Sisti & R. Van Weelderen
The upgrade of the cryogenics for the HL-LHC will consist of the following: • - The design and installation of two new cryogenic plants at P1 and P5 for high luminosity insertions. This upgrade will be based on a new sectorization scheme aimed at separating the cooling of the magnets in these insertion regions from the arc magnets and considering the newt feedboxes and superconducting links located in underground infrastructures. • - The design and...

Cold powering of the superconducting circuits

A. Ballarino, P. Cruikshank, J. Fleiter, Y. Leclercq, V. Parma & Y. Yang
For the HL-LHC project, a novel concept for the cold powering of superconducting magnets has been developed. It is based on a new type of superconducting lines (hereafter referred to as Superconducting (SC) Links) that have been developed to transfer the current to the new HL-LHC insertion region magnets from remote distances. Power converters and current leads will in fact be located in the new underground areas (UR) excavated for the HL-LHC (technical galleries running...

Warm powering of the superconducting circuits

M. Martino, J-P. Burnet, M. Cerqueira Bastos, V.R. Herrero Gonzales, N. Kuczerowski, S. Pittet, H. Thiesen, Y. Thurel, B. Todd & S. Yammine
The warm powering of the HL-LHC involves the new circuits of the Inner Triplets and the Separation/Recombination magnets in Point 1 and Point 5, the powering of the 11 T magnets in Point 7, and the final R2E consolidation phase in LS3. The LHC was built with modular power converters to facilitate maintenance and integrate the redundancy principle. Redundancy was foreseen in power converters rated above 600 A. This has proven to be a real...

Circuit layout, powering and protection

F. Rodríguez Mateos, T.D. Catalão Rolhas Da Rosa, F. Menéndez Cámara, S. Yammine & M. Zerlauth
During LS2 and LS3, the HL-LHC upgrade will impose many changes to the magnet circuits of the LHC long- straight sections at points 1 and 5. The magnets will be installed in the machine during LS3. In addition to these changes, during LS2, two main dipole magnets (MB) will be replaced by 11T cryo-assemblies (MBH) in order to allow the addition of two extra collimators at warm to intercept dispersive beam losses originating from the...

Technical infrastructure

L. Tavian, M. Battistin, S. Bertolasi, C. Bertone, B. Di Girolamo, N. Dos Santos, K. Foraz, T. Hakulinen, P. Mattelaer, P. Muffat & P. Pepinster
The HL-LHC technical infrastructure includes the civil engineering, the electrical distribution, the cooling & ventilation, the access & alarm system, the technical monitoring, the transport, the logistics, the storage, and the operational safety.

Beam instrumentation and long-range beam–beam compensation

R. Jones, E. Bravin, T. Lefèvre & R. Veness
The extensive array of beam instrumentation with which the LHC is equipped has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. Much of this equipment will need consolidation by the time the LHC enters the High-Luminosity (HL) era, while the upgrade itself brings a number of new challenges. The installation of a completely new final focus system in the two high-luminosity LHC insertions implies the development of new...

Integration, (de-)installation and alignment

P. Fessia & H. Mainaud Durand
The HL-LHC will require modifying the machine and infrastructure installations of the LHC in several points along the Accelerator Ring, in particular: P1, P2, P4, P5, P6, P7 and P8. Part of the modifications and improvement in P2, P4, P7 and P8 shall be completed during Long Shutdown 2 (LS2) and be operational for LHC Run 3, while the largest part of the interventions will take place in Long Shutdown 3 (LS3) and they will...

RF systems

R. Calaga, P. Baudrenghien, O. Capatina, E. Jensen & E. Montesinos
The HL-LHC beams are injected, accelerated, and stored to their nominal energy of 7 TeV by the existing 400 MHz superconducting RF system of the LHC. A novel superconducting RF system consisting of eight cavities per beam for transverse deflection (aka crab cavities) of the bunches will be used to compensate the geometric loss in luminosity due to the non-zero crossing angle and the extreme focusing of the bunches in the HL-LHC. Due to doubling...

IT string and hardware commissioning

M. Bajko & M. Pojer
The HL-LHC IT string (IT string) is a test stand for the HL-LHC, whose goal is to validate the collective behaviour of the IT magnets and circuits in conditions as near as possible to the operational ones. Each individual magnet circuit will be powered through a SC link and its associated current leads up to the ultimate operational current while cooled to 1.9 K in liquid helium. The test stand will be installed in the...

Introduction

I. Dawson
This report documents the knowledge and experiences gained by the LHC experiments in running vertex and tracker detector systems in extreme radiation environments and concludes a series of workshops held at CERN. By the time of the workshops, the last one held on February 2019, the LHC machine had delivered a large fraction of the design luminosity to the experiments and the deleterious effects of radiation on detector performance and operation were being observed and...

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