CERN Accelerating science

Article
Title Electrostatic dust lofting: a possible cause for beam losses at CERN’s LHC
Author(s) Elliott, A (Florida Inst. Tech.) ; Wang, X (U. Colorado, Boulder) ; Horanyi, M (U. Colorado, Boulder) ; Taylor, K (U. Colorado, Boulder) ; Schmidt, R (Darmstadt, Tech. Hochsch.) ; Wiesner, C (CERN) ; Wollmann, D (CERN) ; Belanger, P (TRIUMF)
Publication 2023
Number of pages 4
In: JACoW IPAC 2023 (2023) MOPA065
In: 14th International Particle Accelerator Conference (IPAC 2023), Venice, Italy, 7 - 12 May 2023, pp.MOPA065
DOI 10.18429/JACoW-IPAC2023-MOPA065
Subject category Accelerators and Storage Rings
Abstract Dust particles interacting with the proton beams have caused many thousand beam-loss events at CERN's Large Hadron Collider (LHC), some of which led to premature beam dumps and even magnet quenches. It has been hypothesized that dust particles on the vacuum chamber wall of the LHC are negatively charged due to electron clouds and can detach from the chamber wall by the electric field of the beam. To test this hypothesis, we performed experiments to study the electrostatic lofting of dust particles from a conducting surface. A monolayer of SiO2 particles with a diameter of <44 um is deposited on such a surface and exposed to an electron beam of 80-140 eV. An external electric field of up to 3 kV/cm is then applied. The properties of dust charging and levitation are characterized from recorded high-speed videos. We observed that dust particles are lofted both during electron beam charging and during the application of the external electric field. Our results provide experimental evidence that dust particles can be detached from a conducting surface and help to understand the mechanism of how dust particles can enter the LHC beam.
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 Záznam vytvorený 2023-12-21, zmenený 2023-12-21


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