Protection of the CERN Large Hadron Collider

Schmidt, R.; Assmann, R.; Carlier, E.; Dehning, B.; Denz, Reiner; Goddard, B.; Holzer, Eva Barbara; Kain, V.; Puccio, B.; Todd, Benjamin; Uythoven, Jan; Wenninger, J.; Zerlauth, Markus

doi:10.1088/1367-2630/8/11/290

Cited by 54 publications

(41 citation statements)

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“…The introduction in recent years of new, extremely energetic particle accelerators such as the Large Hadron Collider (LHC) [1] brought about the need for advanced cleaning and protection systems in order to safely increase the energy and intensity of particle beams to unprecedented levels [2].…”

Section: Introductionmentioning

confidence: 99%

An experiment to test advanced materials impacted by intense proton pulses at CERN HiRadMat facility

Bertarelli

Berthomé

Boccone

et al. 2013

Nuclear Instruments and Methods in Physics Research Section B:

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SummaryPredicting the consequences of highly energetic particle beams impacting protection devices as collimators or high power target stations is a fundamental issue in the design of state-ofthe-art facilities for high-energy particle physics. These complex dynamic phenomena, which may induce material phase transitions, extended density changes, shock waves generation, explosions, material fragment projections etc., have been successfully simulated resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, however, these codes require reliable material constitutive models that, at the extreme conditions induced by a destructive beam impact, are scarce and often inaccurate. In order to derive or validate such models (Equations of State, Strength Models, Failure Models), a comprehensive, first-of-its-kind experiment has been recently carried out at CERN HiRadMat facility: performed tests entailed the controlled impact of intense and energetic proton pulses on a number of specimens made of six different materials. Experimental data were acquired, mostly in real time, relying on extensive embedded instrumentation (strain gauges, temperature and vacuum sensors) and on remote acquisition devices (laser Doppler vibrometer and high-speed camera). The dynamic ranges of the digital acquisition system were sufficient to acquire the very fast and intense shock waves generated by the impact. The high speed video camera allowed capturing a number of frames during the time of flight of the material fragments projected away from impacted specimens. This information is then benchmarked against advanced numerical simulations. Preliminary results of the tests are discussed. In depth post-irradiation analyses are foreseen once the specimens have reached a sufficiently low level of activation. The experimental method presented in this paper may find applications to test materials under very high strain rates and temperatures in domains well beyond particle physics (severe accidents in fusion and fission nuclear facilities, space debris impacts, fast and intense loadings on materials and structures etc.).-2 -

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Section: Introductionmentioning

confidence: 99%

An experiment to test advanced materials impacted by intense proton pulses at CERN HiRadMat facility

Bertarelli

Berthomé

Boccone

et al. 2013

Nuclear Instruments and Methods in Physics Research Section B:

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“…7. Since a fast beam loss of around 2 MJ can damage vacuum chambers and magnets, the Machine Protection Systems (MPS) must constantly survey a large number of beam and equipment parameters [11]. Whenever an abnormal condition is detected the MPS fires fast pulsing magnets to extract the beams within a few turns to a beam dump to prevent damage to LHC accelerator components.…”

Section: Lhc Operation Challengesmentioning

confidence: 99%

The LHC collider

Wenninger

2015

Comptes Rendus. Physique

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The first three year run of the Large Hadron Collider (LHC) ended in the spring of 2013. During this period, the collider was operated mainly at beam energies of 3.5 and 4 TeV. The performances that have been achieved during that first run and the challenges for commissioning and operating the LHC are presented. A brief outlook into the upcoming run at an energy of 6.5 TeV will be given. © 2015 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.r é s u m é La première période d'opération du grand collisionneur à hadrons (GCH) s'est terminée au printemps 2013. Pendant cette période, le collisionneur a fonctionné principalement à des énergies par faisceau de 3,5 et 4 TeV. La performance atteinte pendant cette période ainsi que les défis de la mise en route du GCH sont présentés. Un apercu de la prochaine période d'opération à 6,5 TeV est donné.

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“…As explained in Schmidt (2006), requirements for safe operation necessitate early detection of failures within the equipment, and active monitoring of the beam with fast and reliable beam instrumentation (mainly beam loss monitors). When operating with circulating beams, the time constants for beam loss after a failure extends from % ms to many seconds that requires that the failures must be detected sufficiently early and transmitted to the beam interlock system that triggers a beam dump.…”

Section: Machine Protection and Beam Absoebersmentioning

confidence: 99%

Simulations of full impact of the Large Hadron Collider beam with a solid graphite target

et al. 2009

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The Large Hadron Collider (LHC) will operate with 7 TeV/c protons with a luminosity of 10 34 cm 22 s 21 . This requires two beams, each with 2808 bunches. The nominal intensity per bunch is 1.15 Â 10 11 protons and the total energy stored in each beam is 362 MJ. In previous papers, the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected onto a copper target. Another failure scenario is the deflection of beam, or part of it, into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC close to the beam, since carbon is the material that is most suitable to absorb the beam energy without being damaged. In case of a failure, it is very likely that such absorbers are hit first, for example, when the beam is accidentally deflected. Some type of failures needs to be anticipated, such as accidental firing of injection and extraction kicker magnets leading to a wrong deflection of a few bunches. Protection of LHC equipment relies on the capture of wrongly deflected bunches with beam absorbers that are positioned close to the beam. For maximum robustness, the absorbers jaws are made out of carbon materials. It has been demonstrated experimentally and theoretically that carbon survives the impact of a few bunches expected for such failures. However, beam absorbers are not designed for major failures in the protection system, such as the beam dump kicker deflecting the entire beam by a wrong angle. Since beam absorbers are closest to the beam, it is likely that they are hit first in any case of accidental beam loss. In the present paper we present numerical simulations using carbon as target material in order to estimate the damage caused to carbon absorbers in case of major beam impact.

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Protection of the CERN Large Hadron Collider

Cited by 54 publications

References 1 publication

An experiment to test advanced materials impacted by intense proton pulses at CERN HiRadMat facility

An experiment to test advanced materials impacted by intense proton pulses at CERN HiRadMat facility

The LHC collider

Simulations of full impact of the Large Hadron Collider beam with a solid graphite target

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