{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"77c4fe677197140bc589f8dee5313eb272571311c1d9ac6042ace81b3289c960","created":"2026-10-03T07:17:56Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"b609afa49c3504bf8c09017d40fe6cf2374e51d3906a0883cd26b7adaeb90862","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"beams.collective-instabilities.dust-release-mechanism","kind":"phenomenon","literature_status":"partially-resolved","n":"1","parents":[],"plain":"Micron-sized dust grains fall from the LHC vacuum chamber walls into the beam and cause sudden losses that can quench magnets; what makes them detach is unclear.","posed_since":"2010","precise":"Fast loss events in the LHC (called UFOs, unidentified falling objects) last of order 1e-3 s and are modeled as micron-scale dust grains entering the proton beam, being ionized and repelled; this dust-beam dynamics was analyzed in 2020. Determine the release mechanism (electrostatic detachment driven by beam-induced charging or electron cloud, mechanical vibration, magnetic forces on ferromagnetic grains) and predict the event rate versus beam intensity, bunch spacing and cumulative beam time.","problem_ref":null,"references":"","settled_by":"Laboratory release tests on beam-screen surfaces under electron bombardment and electric field that reproduce the measured dependence of the event rate on intensity and conditioning time.","status_note":"Dust-beam interaction dynamics were modeled and matched to loss signals in 2020 (Lindstrom et al., https://doi.org/10.1103/PhysRevAccelBeams.23.124501); the release step is not established.","title":"Release mechanism of dust grains causing fast LHC beam losses","topic_ref":"dd60e631adb08b9b18495c7a3ab1cfd2ffd7375b33108ba5cf5ec6cce7af2868"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"58464bb5aad78603c230dcdcffe3735d686418908fcdcb1c899a41d1a34301e3","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"42354282549059a943d67f630479f5e75db96015bfb96090ad0566993c9bcffa","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"bNuhIlnKgX_k8y2TKJoYBYdw9keaoDCy9N7-Q3Mor3WYXHXEsXAEZhFk5g3K5LsN4W-mFBdBUr5ZjF5wG2-9CA"},"schema":"pubphys.envelope/1"},"record_hash":"58464bb5aad78603c230dcdcffe3735d686418908fcdcb1c899a41d1a34301e3","leaf_index":656}