Dynamics of the interaction of dust particles with the LHC beam

Lindstrom, Bjorn Hans Filip; Belanger, Philippe; Gorzawski, Arkadiusz; Král, J.; Lechner, Anton; Salvachua, Belen; Schmidt, R.; Siemko, A.; Vaananen, Mika Petteri; Valuch, Daniel; Wiesner, Christoph; Wollmann, Daniel; Zamantzas, Christos

doi:10.1103/physrevaccelbeams.23.124501

Cited by 8 publications

(20 citation statements)

References 15 publications

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“…The signal distribution nonetheless demonstrates the abundance of smaller dust particulates in the arc vacuum system, which is also confirmed by the dust samples collected in run II [32]. It was also observed that the time profiles of events can typically be described by a skewed Gaussian distribution [4,6,22] (see Fig. 6).…”

Section: Characteristics Of Beam-dust Particle Interactionssupporting

confidence: 65%

“…Dust or macroparticle-related beam losses were, however, not expected to be perturbing for a proton collider since dust particles become rapidly ionized and repelled from the beams. Simulations and experimental observations in the LHC indeed support the hypothesis that dust grains are expelled before reaching the beam core [18][19][20][21][22]. The events typically last less than a millisecond, i.e.…”

Section: Introductionmentioning

confidence: 70%

“…The characteristics of dust-induced BLM signals have been studied since run I [2,6,[19][20][21][22]47]. Different observations were made, which provided some insight into the nature of these events.…”

Section: Characteristics Of Beam-dust Particle Interactionsmentioning

confidence: 99%

“…Dust-induced loss events have been put under scrutiny since their first occurrence in run I, by studying event rates and empirical correlations with beam parameters [2-6, 8, 9], by analysing dust samples from the vacuum chamber of magnets [7,32], and by modeling the motion of dust particles in the beam [18-20, 33, 34]. In combination with bunch-by-bunch beam diagnostics, individual dust particle trajectories could be reconstructed [21,22]. The simulation studies and measurements also indicated that the radius of dust particles is smaller than 100 µm [19,20] and that the dust grains likely carry a negative charge when entering the beam [22,35].…”

Section: Introductionmentioning

confidence: 99%

“…In combination with bunch-by-bunch beam diagnostics, individual dust particle trajectories could be reconstructed [21,22]. The simulation studies and measurements also indicated that the radius of dust particles is smaller than 100 µm [19,20] and that the dust grains likely carry a negative charge when entering the beam [22,35]. Despite these findings, a better understanding of these events is needed for quantifying the performance impact on the LHC, the HL-LHC and other future high-energy proton colliders like the FCC-hh [36].…”

Section: Introductionmentioning

confidence: 99%

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Study of dust-induced beam losses in the cryogenic arcs of the CERN Large Hadron Collider

Lechner,

Bélanger,

Efthymiopoulos

et al. 2021

Preprint

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The interaction of dust particles with the LHC proton beams accounts for a major fraction of irregular beam loss events observed in LHC physics operation. The events cease after a few beam revolutions because of the expulsion of dust particles from the beam once they become ionized in the transverse beam tails. Despite the transient nature of these events, the resulting beam losses can trigger beam aborts or provoke quenches of superconducting magnets. In this paper, we study the characteristics of beam-dust particle interactions in the cryogenic arcs by reconstructing key observables like nuclear collision rates, loss durations and integral losses per event. The study is based on events recorded during 6.5 TeV operation with stored beam intensities of up to ∼ 3 × 10 14 protons per beam. We show that inelastic collision rates can reach almost 10 12 collisions per second, resulting in a loss of up to ∼ 1.6 × 10 8 protons per event. We demonstrate that the experimental distributions and their dependence on beam parameters can be described quantitatively by a previously developed simulation model if dust particles are assumed to be attracted by the beam. The latter finding is consistent with recent time profile studies and yields further evidence that dust particles carry a negative charge when entering the beam. We also develop different hypotheses regarding the absence of higher-loss events in the measurements, although such events are theoretically not excluded by the simulation model. The results provide grounds for predicting dust-induced beam losses in presence of higher-intensity beams in future runs of the High-Luminosity LHC.

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Section: Characteristics Of Beam-dust Particle Interactionssupporting

confidence: 65%

Section: Introductionmentioning

confidence: 70%

Section: Characteristics Of Beam-dust Particle Interactionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Study of dust-induced beam losses in the cryogenic arcs of the CERN Large Hadron Collider

Lechner,

Bélanger,

Efthymiopoulos

et al. 2021

Preprint

Self Cite

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Photoelectric charging and lofting of dust particles on a conducting surface with external electric fields

Taylor,

Elliott,

Wang

et al. 2024

Physics of Plasmas

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We present a laboratory study of photoelectric charging of dust particles and their lofting on a conducting surface in the presence of external electric fields. Insulating particles with diameter <45 μm are dispersed on a conducting surface exposed to ultraviolet (UV) light. In addition to the UV exposure, a positive or negative external electric field is applied. Independent of the orientation of the external electric field, the dust particles are found to be positively charged but with different mechanisms. It is shown that the orientation of the external electric field controls the dynamics of photoelectrons emitted from the dust particles and the conducting substrate surface. Distinctly different lofting results are shown between these two electric field cases. The results provide insight for understanding dust charging and release and helping develop mitigation solutions in particle accelerators, semiconductor manufacturing, fusion reactors, and space exploration to planetary bodies.

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Measurement of transverse beam emittance of split beams for the CERN Proton Synchrotron Multi-Turn Extraction

G.¹,

Cerutti²,

Esposito³

et al. 2022

J. Inst.

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Crossing a horizontal nonlinear resonance is the approach that can be used to split a beam in several beamlets with the goal to perform multi-turn extraction from a circular particle accelerator. Such an approach has been successfully implemented in the CERN Proton Synchrotron and is used routinely for the production of high-intensity proton beams for fixed-target physics at the Super Proton Synchrotron. Recently, thanks to the deployment of diamond detectors, originally installed to monitor the beam losses at extraction, it has been possible to measure the horizontal beam emittance of the split beam just prior to extraction. This is the first time that an emittance measurement is attempted for split beams, i.e. in a regime of highly nonlinear beam dynamics. In this paper, the technique is presented and its application to the analysis of the experimental data is presented and discussed in detail. This result is essential for the performance assessment of the splitting process and for the design of further performance improvements.

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Dynamics of the interaction of dust particles with the LHC beam

Cited by 8 publications

References 15 publications

Study of dust-induced beam losses in the cryogenic arcs of the CERN Large Hadron Collider

Study of dust-induced beam losses in the cryogenic arcs of the CERN Large Hadron Collider

Photoelectric charging and lofting of dust particles on a conducting surface with external electric fields

Measurement of transverse beam emittance of split beams for the CERN Proton Synchrotron Multi-Turn Extraction

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