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90m exercise

90m exercise. 90m "proper" VdM scans in the 90m/10m optics. RP alignment and data taking ( + loss maps ). TOTEM. ALFA. priority 1. move all pots to ~10 . move all pots to ~10 . align one V-pair b1 ~1h. align V-pair b2 ~1h. move aligned V pots to ~4.5 .

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90m exercise

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  1. 90m exercise 90m "proper" VdM scans in the 90m/10m optics

  2. RP alignment and data taking ( + loss maps ) TOTEM ALFA priority 1 move all pots to ~10 move all pots to ~10 align one V-pair b1 ~1h align V-pair b2 ~1h move aligned V pots to ~4.5 move aligned V pots to ~5.5 align one V-pair b2 ~1h align V-pair b1 ~1h align b1 H pots ~1h align V-pair b2 ~1h move aligned H pots to ~7 (?)  align b2 H pots ~1h align V-pair b1 ~1h stand alone take data ~2h take data ~4h in-ATLAS take data ~1h take data ~2h take data ~2h bonus take data ~4h calibration data taking ~2h move out RPs, loss maps~1h

  3. The short-version check list • Pot motion is OK, test during ramp down of last fill before 90m (TOTEM/ALFA) • including motor step counter reset. Only possible if OVERRIDE = TRUE. • can be done at any time, but ideally before the bunches are actually injected. • Detectors are OK: internal checks by TOTEM/ALFA/ATLAS before starting the 90m run • Very relaxed setup beam flag limit is set (EiC/MC) • Pots are in OVERRIDE mode, no dump when move in ADJUST (TOTEM/ALFA) • TOTEM: done in the very first step (motion check & step counter reset) by TOTEM expert. • ALFA: correct. The mvt of the ALFA pots will be done by one expert. The OVERRIDE setting is done by the ATLAS SLIMOS on request of the ALFA expert. • BLM thresholds have been correctly set (Jorg W) • Pots interlock limits are correctly set (Stefano R / Jorg W) • TOTEM expert can check all TOTEM limits via DCS. • ALFA: as TOTEM we have in the meantime the reading of these settings (via DCS). Important to have a collimation expert around. • Time out of very relaxed setup beam flag (voice warning, be vigilant...) • Check AC dipole is working before refilling (EiC/MC) • Beams with adequate intensity and emittance are prepared in advance in SPS (=> MC) • probe bunches: N~9-11e9,   2um, nominal bunches: N~6-8e10,   2um before ramp • Check that BSRT have optimal settings and measure emittances bunch by bunch • After injection and after unsqueeze: wire scans (bunch by bunch) Anything else ?

  4. Instability ! Roman pots beam-based alignment dcct2 dcct1 inj loss maps TOTEM/ALFA data taking loss maps VDM fill beta-beat k-modulation BPM MD LBDS self trigger PC trip Energy beta* SIS dump move TOTEM and collims closer, ALFA retracts for a moment... RP align ALFA RP positions 58h = 2.4 days H RP align TOTEM RP positions V RP align

  5. ALFA scraping Min.bias trigger rate during scraping RP 5 + 6 RP 1 + 2 RP 7 + 8 RP 3 + 4

  6. 90m exercise Not an easy exercise! Unusual hypercycle (optics), Unusual filling scheme (mixing probes and sub-nominal bunches) Many goals to achieve in a short time (sometimes in parallel) Reduced expert crew to handle Once again, a intense cooperation between experiments and machine operation, orbit, sequence, collimators, betatron loss maps, async dump, with subsequent analysis, machine protection aspects, etc.

  7. 90m thanks! A big MANY THANKS to our machine* colleagues from the experiments and from myself! *including injector! In particular to Sophie, Rogelio, Helmut, Marek, RalphS, Glenn, ... Gianluca, Florian, ... Verena, Reyes, Delphine, Alick, Stefano, Ron, Guy, GHH, Lasse, ... Jorg, Bernhard, Mike, Brennan, Ralph, rMPP, ...

  8. In addition: VdM at 90m/10m • Reminder: • Total beam current measurements is now reaching the level of sub-percent total accuracy! (thanks to BE-BI and Colin Barschel!) • see Bunch Currdnt Normalisation WG (under cern.ch/lpc) • Other sources of uncertainties become important and can substantially affect the total uncertainty on the absolute luminosity calibration • ghost charge • relative bunch population • reproducibility of scans • shape distortions ? • coupling effects ? • length scale precision • etc.

  9. VdM overview fill 2234 ALICE LHCb ALICE ATLAS

  10. VdM measurements fill 2234 • FillNr 2234, Fri 21.10.2011 06:26 => Fri 21.10.2011 14:29 ~8.0h3.5 TeV, Single_36b_4_16_16_4bpi9injLHCb +, ALICE +/+, N=~ 1e11 p/bch, 90 10 90 10 m • Emittance (3-5 um) was a bit larger than desired, but OK • Performed VdM programme: 06:43-07:34 ALICE07:34-11:18 LHCb11:18-13:47 ALICE13:47-14:29 ATLAS(NB: no request from CMS)

  11. VdM measurements fill 2234 • Detailed:o 06:43-07:06 VdM H in IP2o 07:06-07:34 VdM V in IP2o 07:34-07:51 VdM H in IP8o 07:51-08:06 VdM V in IP8o 08:10-08:24 "Fast" length scale calibration H in IP8o 08:24-08:38 "Fast" length scale calibration V in IP8o 09:04-09:51 Beam-gas data at 4 extreme separations IP8o 09:52-10:24 Fast 2-beam VdM scans H-V-H-V in IP8o 10:24-11:18 Fast 1-beam VdM scans H-V-H-V in IP8o 11:18-11:49 VdM H in IP2 reversed directiono 11:49-12:17 VdM V in IP2 reversed directiono 12:17-12:44 VdM V in IP2 with 140um separation in Ho 12:44-13:08 VdM H in IP2 with 140um separation in Vo 13:17-13:32 "Fast" length scale calibration H in IP2o 13:32-13:47 "Fast" length scale calibration V in IP2o 13:47-14:29 Started setting up for IP1, but dumped

  12. preliminary LDM results for VdM fill 2234

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