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SPS scrubbing run in 2014: a first look

SPS scrubbing run in 2014: a first look. H.Bartosik , G. Iadarola , G. Rumolo. Many thanks to: G. Arduini. LIU-SPS Coordination Meeting, 2/4/2014. SPS scrubbing run 2014.

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SPS scrubbing run in 2014: a first look

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  1. SPS scrubbing run in 2014: a first look H.Bartosik, G. Iadarola, G. Rumolo Many thanks to: G. Arduini LIU-SPS Coordination Meeting, 2/4/2014

  2. SPS scrubbing run 2014 • Goal: qualify the loss of conditioning due to LS1, recover 2012 performance with 25ns beams and quantify amount of beam/time needed • basis for LIU strategy on e-cloud mitigation – coating vs scrubbing • Qualification criterion: beam quality measurements • Hopefully achieve by the end of the two weeks: • 25 ns, 4 batches, up to 1.3e11ppb, emittances below nominal, • no blowup along the train

  3. From 2014 injector schedule

  4. Beam requirements • From the PS: • The scrubbing beam: • 25 ns beam (std. production scheme, 72 b., ~1.25e11 ppb) • As a backup at early stages (if pressure rise or instabilities are too violent) and for setup: • 50 ns beam (std. production scheme, 36 b., up to 1.7e11 ppb) • For setup: • Usual probes, indivs… • Optionally, for scrubbing qualification: • 25 ns beam (BCMS production scheme, 48 b., ~1.25e11 ppb) • From earlier SPS commissioning: • Basic setup (injection, orbit, working point, RF, damper) of 26 GeV flat bottom cycle (1 b. or 6 b. 50 ns, Q20) • Needed also for Q20 alignment, HiRadMat? • In the early stages we do not need beam quality for efficient scrubbing •  we should aim at circulating a “good enough beam” as soon as possible and work on fine tuning in parallel with scrubbing

  5. Scrubbing cycles • In the beginning we expect poor beam lifetime and vacuum leading to frequent dump/refill • In the later stages (due to longer electron cloud risetime – lower SEY) efficient scrubbing only when 4 (or more) batches circulating in the machine •  Flat bottom cycles with different lengths should be prepared: • 6 BPs (7.2 s) Inj. Inj. Inj. Inj. Inj. Inj. Inj. Inj. Inj. Inj. Dump Dump Dump • 18 BPs (21.6 s) • 33 BPs (39.6 s)

  6. Scrubbing run planning (2014) – to be steered on the fly Saturday Sunday Monday Tuesday Wednesday Thursday Friday Setup (50 ns conditioning – mainly sensive elements, e.g. kickers, ZSs, TIDV) 25 ns (7.2 sec cycle) Up to 72b. Dump Dump Dump Inj. Inj. Inj. • Possible supercycle Saturday Sunday Monday Tuesday Wednesday Thursday Friday

  7. Scrubbing run planning (2014) – to be steered on the fly Saturday Sunday Monday Tuesday Wednesday Thursday Friday Setup (50 ns conditioning – mainly sensive elements, e.g. kickers, ZSs, TIDV) 25 ns (7.2 sec cycle) 25 ns (21.6 sec cycle) Up to 72b. Up to 288 b. • Possible supercycle Saturday Sunday Monday Tuesday Wednesday Thursday Friday 25 ns (21.6 sec cycle) Inj. Inj. Inj. Inj. Dump

  8. Scrubbing run planning (2014) – to be steered on the fly Saturday Sunday Monday Tuesday Wednesday Thursday Friday Setup (50 ns conditioning – mainly sensive elements, e.g. kickers, ZSs, TIDV) 25 ns (7.2 sec cycle) 25 ns (21.6 sec cycle) Up to 72b. Up to 288 b. • Possible supercycle Saturday Sunday Monday Tuesday Wednesday Thursday Friday 25 ns (21.6 sec cycle) 25 ns (39.6 sec cycle) Dump Up to 6 batches (?) Up to 1.4e11 (?) Inj. Inj. Inj. Inj. Inj. Radial steering to clean slightly wider area of dipole chambers

  9. Scrubbing run planning (2014) – to be steered on the fly • Possible supercycle Saturday Sunday Monday Tuesday Wednesday Thursday Friday Setup (50 ns conditioning – mainly sensive elements, e.g. kickers, ZSs, TIDV) 25 ns (7.2 sec cycle) 25 ns (21.6 sec cycle) Up to 72b. Up to 288 b. Inj. Inj. Inj. Inj. Inj. Dump Saturday Sunday Monday Tuesday Wednesday Thursday Friday 25 ns (21.6 sec cycle) 25 ns (39.6 sec cycle) Up to 6 batches (?) Up to 1.4e11 (?) Radial steering to clean slightly wider area of dipole chambers Scrubbing qualification Setup LHC production cycle (450 GeV)

  10. Measurements • Caveat: the goal is to accumulate the largest possible e- dose on the vacuum chambers. Tests which compromise the scrubbing efficiency should be kept to the minimum possible • On the other hand, we should collect as much data as possible to learn about ecloudeffects and scrubbing process in the SPS. We should record: • BCT/FBCT (to estimate beam dose) • Pressure along the ring (1 Hz log rate) • Electron cloud monitors (MBA StSt, MBB StSt, MBB a-C, QuadrupoleStSt) • Shielded pickup (scope?) • In situ SEY measurement (if available) • Removable StSt sample (for lab SEY measurement) • COLDEX (?) • Beam transverse oscillations • BBQ, LHC BPMs, Headtail monitor, fast pickup from HBWD setup, damper based diagn. (?) • Beam transverse size • Wirescanners (bunch by bunch), BGI (?), BSRT(?) • Longitudinal parameters (BQM (?), mountain range, faraday cage scope)

  11. Thanks for your attention!

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