Performance reach of the "phase 1" LHC collimation system

Robert‐Demolaize, G.; Assmann, R.; Bracco, Chiara; Redaelli, Stefano; Weiler, T.

doi:10.1109/pac.2007.4440840

Cited by 25 publications

(29 citation statements)

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“…Up to now, the FORTRAN program SixTrack has been the main tool used to calculate dynamical aperture in the LHC , and, incorporating the scattering model known as K2 [54], has been used for many studies of the LHC collimation system and resulting the loss maps [4][5][6][7]55]. However a second program was felt to be desirable, as an independent check and to provide a more flexible and future-proof design to which new features, such as this model, can readily be added.…”

Section: Simulation Of Lhc Loss Maps Using Merlinmentioning

confidence: 99%

“…18 The difference of the optical β-functions for the nominal LHC between MADX [56] and MERLIN pipe, it is considered lost: the particle is removed from the bunch and the location at which this takes place is recorded, using a default bin size of 10 cm. This is necessary as these conventions are those used by existing studies [4][5][6][7]55]; against which we benchmark the new code. They mark a sensible line between the study of long-distance (multi-turn) effects, which are the subject of simulations such as these, and short range effects which are the subject of programs like FLUKA [58] and GEANT4 [59].…”

Section: Simulation Of Lhc Loss Maps Using Merlinmentioning

confidence: 99%

“…To study the beam halo we do not consider inelastic scatters, double-diffractive scatters, or SD interactions pp → X p, in which the beam proton breaks up: for such events all the energy is lost locally, within 50 m, according to studies by the CERN collimator group [6,7]. With elastic and singlediffractive scattering ( pp → pX) the emerging protons are only slightly affected and may survive several turns before being lost.…”

Section: Introductionmentioning

confidence: 99%

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The practical Pomeron for high energy proton collimation

et al. 2016

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We present a model which describes proton scattering data from ISR to Tevatron energies, and which can be applied to collimation in high energy accelerators, such as the LHC and FCC. Collimators remove beam halo particles, so that they do not impinge on vulnerable regions of the machine, such as the superconducting magnets and the experimental areas. In simulating the effect of the collimator jaws it is crucial to model the scattering of protons at small momentum transfer t, as these protons can subsequently survive several turns of the ring before being lost. At high energies these soft processes are well described by Pomeron exchange models. We study the behaviour of elastic and single-diffractive dissociation cross sections over a wide range of energy, and show that the model can be used as a global description of the wide variety of high energy elastic and diffractive data presently available. In particular it models low mass diffraction dissociation, where a rich resonance structure is present, and thus predicts the differential and integrated cross sections in the kinematical range appropriate to the LHC. We incorporate the physics of this model into the beam tracking code MERLIN and use it to simulate the resulting loss maps of the beam halo lost in the collimators in the LHC.

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Section: Simulation Of Lhc Loss Maps Using Merlinmentioning

confidence: 99%

Section: Simulation Of Lhc Loss Maps Using Merlinmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The practical Pomeron for high energy proton collimation

et al. 2016

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“…Although the linear elements can be treated as thick elements, the necessity of tracking large numbers of halo particles over thousands of turns would require excessive CPU resources. Due to this a thin lens model approximation is used instead [3].…”

Section: Tracking Through a Thin Lens Modelmentioning

confidence: 99%

“…For the LHC collimation system design, robust numerical tools were used, providing detailed beam loss maps around the ring [3]. These tools cannot be directly used to low energy synchrotrons as the PS2, not only because of the energy dependence of particle-matter interaction but also because of the approximations that are usually assumed in the magnetic field when tracking on large rings like the LHC.…”

Section: Introductionmentioning

confidence: 99%

Beam loss map simulations and measurements in the CERN PS

Barranco

Berrig

Gilardoni

et al. 2007

2007 IEEE Particle Accelerator Conference (PAC)

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Numerical tools providing detailed beam loss maps, recently developed for the design of the Large Hadron Collider (LHC) collimation system, were adapted to low energy synchrotrons. Using a MADX optics sequence model, these tools are able to track a large number of particles with SixTrack and interact with a realistic aperture model to simulate particle losses all around the ring. Finally the comparison between the dedicated simulations and measured proton loss pattern at the CERN PS showed good agreement between them.

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Sources of machine-induced background in the ATLAS and CMS detectors at the CERN Large Hadron Collider

Bruce

Assmann

Boccone

et al. 2013

Nuclear Instruments and Methods in Physics Research Section A:

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a b s t r a c tOne source of experimental background in the CERN Large Hadron Collider (LHC) is particles entering the detectors from the machine. These particles are created in cascades, caused by upstream interactions of beam protons with residual gas molecules or collimators. We estimate the losses on the collimators with SixTrack and simulate the showers with FLUKA and MARS to obtain the flux and distribution of particles entering the ATLAS and CMS detectors. We consider some machine configurations used in the first LHC run, with focus on 3.5 TeV operation as in 2011. Results from FLUKA and MARS are compared and a very good agreement is found. An analysis of logged LHC data provides, for different processes, absolute beam loss rates, which are used together with further simulations of vacuum conditions to normalize the results to rates of particles entering the detectors. We assess the relative importance of background from elastic and inelastic beam-gas interactions, and the leakage out of the LHC collimation system, and show that beam-gas interactions are the dominating source of machine-induced background for the studied machine scenarios. Our results serve as a starting point for the experiments to perform further simulations in order to estimate the resulting signals in the detectors.

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Performance reach of the "phase 1" LHC collimation system

Cited by 25 publications

References 1 publication

The practical Pomeron for high energy proton collimation

The practical Pomeron for high energy proton collimation

Beam loss map simulations and measurements in the CERN PS

Sources of machine-induced background in the ATLAS and CMS detectors at the CERN Large Hadron Collider

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