Beam-related machine protection for the CERN Large Hadron Collider experiments

Appleby, R. B.; Goddard, B.; Gomez-Alonso, A.; Kain, V.; Krämer, Thomas; Macina, D.; Schmidt, R.; Wenninger, J.

doi:10.1103/physrevstab.13.061002

Cited by 9 publications

(3 citation statements)

References 4 publications

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“…We note that the experimental verification of the numerical simulations is very important from the machine protection point of view [7][8][9]. However, this is not possible with the LHC beam.…”

Section: Introductionmentioning

confidence: 99%

Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider

Tahir

Sancho

Shutov

et al. 2012

Phys. Rev. ST Accel. Beams

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The Large Hadron Collider (LHC) is designed to collide two proton beams with unprecedented particle energy of 7 TeV. Each beam comprises 2808 bunches and the separation between two neighboring bunches is 25 ns. The energy stored in each beam is 362 MJ, sufficient to melt 500 kg copper. Safety of operation is very important when working with such powerful beams. An accidental release of even a very small fraction of the beam energy can result in severe damage to the equipment. The machine protection system is essential to handle all types of possible accidental hazards; however, it is important to know about possible consequences of failures. One of the critical failure scenarios is when the entire beam is lost at a single point. In this paper we present detailed numerical simulations of the full impact of one LHC beam on a cylindrical solid carbon target. First, the energy deposition by the protons is calculated with the FLUKA code and this energy deposition is used in the BIG2 code to study the corresponding thermodynamic and the hydrodynamic response of the target that leads to a reduction in the density. The modified density distribution is used in FLUKA to calculate new energy loss distribution and the two codes are thus run iteratively. A suitable iteration step is considered to be the time interval during which the target density along the axis decreases by 15%-20%. Our simulations suggest that the full LHC proton beam penetrates up to 25 m in solid carbon whereas the range of the shower from a single proton in solid carbon is just about 3 m (hydrodynamic tunneling effect). It is planned to perform experiments at the experimental facility HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS), to compare experimental results with the theoretical predictions. Therefore simulations of the response of a solid copper cylindrical target hit by the SPS beam were performed. The particle energy in the SPS beam is 440 GeV while it has the same bunch structure as the LHC beam, except that it has only up to 288 bunches. Beam focal spot sizes of ¼ 0:1, 0.2, and 0.5 mm have been considered. The phenomenon of significant hydrodynamic tunneling due to the hydrodynamic effects is also expected for the experiments.

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Section: Introductionmentioning

confidence: 99%

Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider

Tahir

Sancho

Shutov

et al. 2012

Phys. Rev. ST Accel. Beams

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“…Any uncontrolled release of the beam energy could result in severe damage to the accelerator equipment. Therefore, the safe operation of high-energy colliders highly relies on robust machine protection systems [8,9]. In the LHC machine protection system, collimators are responsible to clean the beam halo via both momentum collimation and betatron collimation by defining the aperture during routine operation, so that beam-induced quenches of the superconducting magnets can be avoided to the maximum extent.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations of energy deposition caused by 50 MeV—50 TeV proton beams in copper and graphite targets

Nie

Rosell-Tarragó

Chetvertkova

et al. 2017

Phys. Rev. Accel. Beams

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The conceptual design of the Future Circular Collider (FCC) is being carried out actively in an international collaboration hosted by CERN, for the post-Large Hadron Collider (LHC) era. The target center-of-mass energy of proton-proton collisions for the FCC is 100 TeV, nearly an order of magnitude higher than for LHC. The existing CERN accelerators will be used to prepare the beams for FCC. Concerning beam-related machine protection of the whole accelerator chain, it is critical to assess the consequences of beam impact on various accelerator components in the cases of controlled and uncontrolled beam losses. In this paper, we study the energy deposition of protons in solid copper and graphite targets, since the two materials are widely used in magnets, beam screens, collimators, and beam absorbers. Nominal injection and extraction energies in the hadron accelerator complex at CERN were selected in the range of 50 MeV-50 TeV. Three beam sizes were studied for each energy, corresponding to typical values of the betatron function. Specifically for thin targets, comparisons between FLUKA simulations and analytical Bethe equation calculations were carried out, which showed that the damage potential of a few-millimeter-thick graphite target and submillimeter-thick copper foil can be well estimated directly by the Bethe equation. The paper provides a valuable reference for the quick evaluation of potential damage to accelerator elements over a large range of beam parameters when beam loss occurs.

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“…Protection must be considered during all phases of operation, with the accelerator operating with or without beam. Not only damage to accelerator components needs to be considered, but also to the experiments [10].…”

Section: Introduction To This Lecturementioning

confidence: 99%

Introduction to Machine Protection

Schmidt

2016

Preprint

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Protection of accelerator equipment is as old as accelerator technology and was for many years related to high-power equipment. Examples are the protection of powering equipment from overheating (magnets, power converters, high-current cables), of superconducting magnets from damage after a quench and of klystrons. The protection of equipment from beam accidents is more recent, although there was one paper that discussed beam-induced damage for the SLAC linac (Stanford Linear Accelerator Center) as early as in 1967. It is related to the increasing beam power of high-power proton accelerators, to the emission of synchrotron light by electron-positron accelerators and to the increase of energy stored in the beam. Designing a machine protection system requires an excellent understanding of accelerator physics and operation to anticipate possible failures that could lead to damage. Machine protection includes beam and equipment monitoring, a system to safely stop beam operation (e.g. dumping the beam or stopping the beam at low energy) and an interlock system providing the glue between these systems. The most recent accelerator, LHC, will operate with about 3 × 10 14 protons per beam, corresponding to an energy stored in each beam of 360 MJ. This energy can cause massive damage to accelerator equipment in case of uncontrolled beam loss, and a single accident damaging vital parts of the accelerator could interrupt operation for years. This lecture will provide an overview of the requirements for protection of accelerator equipment and introduces various protection systems. Examples are mainly from LHC and ESS.

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Beam-related machine protection for the CERN Large Hadron Collider experiments

Cited by 9 publications

References 4 publications

Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider

Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider

Numerical simulations of energy deposition caused by 50 MeV—50 TeV proton beams in copper and graphite targets

Introduction to Machine Protection

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