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MKI UFO MD. LIBD Meeding Tobias Baer for the UFO MD Team November, 8 th 2011. M. Barnes, B . Goddard, C . Bracco, E. Carlier, S. Jackson, V. Kain, M. Misiowiec, A . Nordt, G . Papotti , J. Uythoven , J. Wenninger , C. Zamantzas. MD Plan. Plan: Study four main aspects :
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MKI UFO MD • LIBD Meeding Tobias Baer for the UFO MD Team November, 8th 2011 M. Barnes, B. Goddard, C. Bracco, E. Carlier, S. Jackson, V. Kain, M. Misiowiec, A. Nordt,G. Papotti,J. Uythoven, J. Wenninger, C. Zamantzas.
MD Plan • Plan: Study fourmainaspects: • Study UFOs atMKQ. • Study delayof UFO occurence w.r.t. MKI kick (UFO dynamics). • Study influenceof e-cloudsolenoids. • Study UFO asymmetrybetweenkickers (pulsing individual kickers). • What was done: • 01:45 – startverificationprocedurewithpilots, bothbeams. 3.5h • 05:20 – injecting 1236b, problemwith PS cavity. 2.75h • 08:05 – 1236b circulating, startdatataking. 2h • 08:43 – startpulsing MKI.05R8. • 08:55 – startpulsing MKI.05L2. • 09:13 – startpulsing all MKQs inbetween MKI pulses. • 09:44 – switch off e-cloudsolenoidsaround MKI.05R8. • 09:56 – beamsdumped(injectioncleaningproblem), MD recovery. 0.5h
UFOs at MKIs • Lossesand MKI pulsesatMKI.5L2. • 3 UFOs in 2 hours. • Lossesand MKI pulsesatMKI.5R8. • Many UFOs, especially afterMKI pulse. • Sometimesvacuumspikeafter MKI pulse. 2 UFOs after MKI pulse uncorrelated UFO MKI pulses Vacuumat MKI.D Switch off e-cloudsolenoids Injection MKI pulses
No UFOs at MKQ • No UFOs around MKQs. Pulsingof MKQs
UFO at 09:54:28 • Study bufferprovidesforthefirst time . beam Lossesofunbuched beam at TDI 11.2s2.56ms resolution UFOs
UFO at 09:40:52 • Assumingfree fall: • UFO dynamicscannotbeexplainedbygravitationalforce. • Manysimilareventsrecorded. 18ms UFO MKI Pulse
Beam Dump • Due tocommunicationproblemwithserver, injectioncleaningwas switched off priorto last MKI pulse. • Losseswere a factor 2.5 higher. Last pulse: Noinjectioncleaning. Injectioncleaning x 2.5 Noinjectioncleaning
Conclusion • Took data for 120 pulses of MKIs and MKQs in effectively 2 hours. • Preliminary results: • No UFOs at MKQ found • Often candidate UFOs after MKI found, especially in Pt.8. Sometimes even several events. • Delay of first event to MKI pulse between 12.8ms and 128ms, expectation from gravitational force: 62ms. • Beams dumped before individual MKI kicks could be performed. • Detailed analysis will follow • UFO rates. • Correlation with e-cloud solenoids and vacuum activity. • UFO distribution between individual MKIs. • etc.
Thank you for your attention! Tobias Baer CERN BE/OP Tobias.Baer@cern.ch Office: +41 22 76 75379 • Further information: • T. Baer et al., “UFOs in the LHC”, IPAC’11, TUPC137, September 2011. • C. Bracco et al., “UFOs at MKIs”, 9th LSWG meeting, August 2011. • T. Baer et al., “MKI UFOs at Injection”, CERN-ATS-Note-2011-065 MD, August 2011.
Initial schedule • Investigation on the sources of the UFOs seen at the injection kickers MKI. The UFO rates will be measured for specified beam condition, by pulsing the MKI on a gap in the partly filled machine. • Difference with previous MD • This time test MKIs both IP2 and IP8, last time only IP8. • The big UFO storms happened at IP2 • First MD was a proof of principle showing that: • We can pulse the individual kicker magnets • That we get interesting data by pulsing without injecting beam • As a dedicated MD, get more them and better statistics • This time we have extended BLM buffers, which allow us to measure the time difference between pulsing and the UFO • Also pulse the MKQ in a beam free gap to check the behaviour of continuously coated ceramic chamber • MKQ @ 450 GeV: kick 1.3 for 2800 V (max), with a total pulse length of 7 s
Initial MD Plan • Check procedure of pulsing a single kicker with 12 pilots in the machine for B1 & B2 (1.0 hours) • Check kicking the MKQ, 4 kickers together with 12 pilots in the machine for B1 & B2 (0.5 hour) • Fill the machine (0.5 hour) • Fill the machine with 1236 bunches and pulse the injection kickers for both IP2 and IP8 • All 4 MKIs (1.5 hour, pulse about every 2 min) • MKI-A only, B1 & B2 (1.5 hours, pulse about every 2 min) • MKI-D only, B1 & B2 (1.5 hours, pulse about every 2 min) • Pulse the MKQ in the beam free gap (1.5 hours, pulse every 2 min)
UFO Studies • Aim: Investigation ofproductionmechanismof UFOs at MKIs bypulsingthe MKIs on thepartlyfilledmachine. • Precedingparallel MKI UFO MD (MD#2) showedthat UFO productioncanbestimulatedby MKI pulsing. • In parallel to TDI studies: UFO studies (postponedfrom MD#3.) • Threemainaspects: • Study UFO asymmetrybetweenkickers (UFO location) • Study delayof UFO occurence w.r.t. MKI kick (UFO dynamics) • Study UFOs atMKQ (Metalizedvacuumchamberaspossiblemitigation)
Tentative Program • Condensed version