Operation of the LHC with Protons at High Luminosity and High Energy

Papotti, Giulia; Albert, Markus; Alemany–Fernández, R.; Crockford, Guy; Fuchsberger, Kajetan; Giachino, Rossano; Giovannozzi, M.; Hemelsoet, Georges-Henry; Höfle, Wolfgang; Jacquet, Delphine; Lamont, Mike; Nisbet, D.; Normann, L.; Pojer, Mirko; Ponce, Laurette; Redaelli, Stefano; Salvachua, Belen; Camillocci, Matteo Solfaroli; Suykerbuyk, Ronaldus; Uythoven, Jan; Wenninger, J.

doi:10.18429/jacow-ipac2016-weoca01

“…The LHC is a bunched machine, in which the accelerated protons are distributed in bunches separated by one or more time steps of 25 ns. The running conditions of the LHC have evolved continuously since the beginning of its operation, and are expected to continue to evolve in the future [7][8][9]. As a representative comparison, we compare the LHC conditions in fill 1440 (October 2010), included in the dataset analyzed in Refs.…”

Section: Muon Detectorsmentioning

confidence: 99%

“…The number of colliding bunches increased by about a factor of 6, from 348 to 2028, facilitated by the reduction of the spacing between proton bunches from 150 ns to 25 ns. The average luminosity per bunch increased by about a factor of 6.5, from 0.6×10 30 cm −2 s −1 to 3.9×10 30 cm −2 s −1 , as a result of several changes including increasing the number of protons per bunch, reducing the transverse widths of the beams, and focusing the beams more tightly [8,9]. The combined increases in collision energy and luminosity per bunch caused the average number of inelastic collisions per crossing (pileup) to increase by about a factor of 8, from 3.6 to 28.…”

Section: Muon Detectorsmentioning

confidence: 99%

Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at √s=13 TeV

Sirunyan

¹

,

Tumasyan

²

,

Adam

³

et al. 2018

View full text Add to dashboard Cite

The CMS muon detector system, muon reconstruction software, and high-level trigger underwent significant changes in 2013-2014 in preparation for running at higher LHC collision energy and instantaneous luminosity. The performance of the modified system is studied using proton-proton collision data at center-of-mass energy √ s = 13 TeV, collected at the LHC in 2015 and 2016. The measured performance parameters, including spatial resolution, efficiency, and timing, are found to meet all design specifications and are well reproduced by simulation. Despite the more challenging running conditions, the modified muon system is found to perform as well as, and in many aspects better than, previously. We dedicate this paper to the memory of Prof. Alberto Benvenuti, whose work was fundamental for the CMS muon detector.

show abstract

“…Energy-deposition studies showed that the vertex of the hadronic showers generating the limiting BLM signals were most likely situated within 1 m from the centre of the dipole MB.C15R8 [33]. In order to investigate the origin of these losses, several local aperture measurements were taken in that area, which revealed the presence of an unidentified lying object (ULO) (more details can be found in [33,34]). A constant monitoring of the ULO position and orientation during Run 2 was carried out by means of local aperture measurements, which were taken at every beam commissioning at the beginning of each run.…”

Section: Local Orbit Bumpsmentioning

confidence: 99%

Beam-based aperture measurements with movable collimator jaws as performance booster of the CERN Large Hadron Collider

Fuster-Martínez

¹

,

Aßmann

²

,

Bruce

³

et al. 2022

View full text Add to dashboard Cite

The beam aperture of a particle accelerator defines the clearance available for the circulating beams and is a parameter of paramount importance for the accelerator performance. At the CERN Large Hadron Collider (LHC), the knowledge and control of the available aperture is crucial because the nominal proton beams carry an energy of 362 MJ stored in a superconducting environment. Even a tiny fraction of beam losses could quench the superconducting magnets or cause severe material damage. Furthermore, in a circular collider, the performance in terms of peak luminosity depends to a large extent on the aperture of the inner triplet quadrupoles, which are used to focus the beams at the interaction points. In the LHC, this aperture represents the smallest aperture at top-energy with squeezed beams and determines the maximum potential reach of the peak luminosity. Beam-based aperture measurements in these conditions are difficult and challenging. In this paper, we present different methods that have been developed over the years for precise beam-based aperture measurements in the LHC, highlighting applications and results that contributed to boost the operational LHC performance in Run 1 (2010–2013) and Run 2 (2015–2018)

show abstract

“…Energydeposition studies showed that the vertex of the hadronic showers generating the limiting BLM signals were most likely situated within 1 m from the centre of the dipole MB.C15R8 [29]. In order to investigate the origin of these losses several local aperture measurements were performed in that area, which revealed the presence of an Unidentified Lying Object (ULO) (more details can be found in [30,29]). A constant monitoring of the ULO position and orientation during Run 2 was carried out by means of local aperture measurements, which were performed at every beam commissioning at the beginning of each run.…”

Section: Local Orbit Bumpsmentioning

confidence: 99%

Beam-based aperture measurements with movable collimator jaws as performance booster of the CERN Large Hadron Collider

Fuster-Martínez¹,

Aßmann²,

Bruce³

et al. 2021

Preprint

0

View full text Add to dashboard Cite

The beam aperture of a particle accelerator defines the clearance available for the circulating beams and is a parameter of paramount importance for the accelerator performance. At the CERN Large Hadron Collider (LHC), the knowledge and control of the available aperture is crucial because the nominal proton beams carry an energy of 362 MJ stored in a superconducting environment. Even a tiny fraction of beam losses could quench the superconducting magnets or cause severe material damage. Furthermore, in a circular collider, the performance in terms of peak luminosity depends to a large extent on the aperture of the inner triplet quadrupoles, which are used to focus the beams at the interaction points. In the LHC, this aperture represents the smallest aperture at top-energy with squeezed beams and determines the maximum potential reach of the peak luminosity. Beam-based aperture measurements in these conditions are difficult and challenging. In this paper, we present different methods that have been developed over the years for precise beam-based aperture measurements in the LHC, highlighting applications and results that contributed to boost the operational LHC performance in Run 1 (2010-2013) and Run 2 (2015-2018).

show abstract

Operation of the LHC with Protons at High Luminosity and High Energy

Cited by 4 publications

References 1 publication

Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at √s=13 TeV

Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at √s=13 TeV

Beam-based aperture measurements with movable collimator jaws as performance booster of the CERN Large Hadron Collider

Beam-based aperture measurements with movable collimator jaws as performance booster of the CERN Large Hadron Collider

Contact Info

Product

Resources

About