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Cycle at 4 TeV and 7 TeV

This text details the commissioning milestones and planning involved in the LHC operation cycle at 4 TeV and 7 TeV energies. It includes information on ramping, squeezing, optics measurements, collision setups, and conclusions drawn from the commissioning process. The text outlines the operational cycles at different energy levels and discusses the efficiency and improvements made in the operation.

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Cycle at 4 TeV and 7 TeV

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  1. Cycle at 4 TeV and 7 TeV Many thanks to: the OP team (S.Redaelli and W.Venturini included!), the optic team and the FIDEL team

  2. outline Commissioning Cycle – operation Cycle @~7 TeV Conclusions

  3. Commissioning (milestones)

  4. Commissioning (milestones)

  5. Commissioning (planning) J.Wenninger @LBOC on 21st Feb We are very good at planning!!!

  6. 2012 changes • Rampat 4 TeV • B3 decaycompensationatflatopseparatedfromtheramp • Squeezeto 0.6m β* • Further optimizationofopticsdistribution in thesqueeze • TiltedLHCbcollisions

  7. Commissioning (ramp) First ramp @4TeV after 2 days (beam 2 dumped after a few minutes at flat top due to a glitch in the safe beam flag) More ramps for tune, orbit and chroma measurements for feed-forward Most changes around 1 TeV, as in 2011 ORBIT: RT corrections applied (in few steps) TUNES: RT corrections applied in few steps (FF removed a tune bump between 100 and 200 s) Snapbackcorrection stillnot perfect(there are still tune correction spikes), to beanalysedduringLS1

  8. Commissioning (squeeze) • In 2012, 2 major changes on the squeeze strategy: • K function smoothing to reduce orbit spikes of 0.1 mm r.m.s, localized near the matched pointsand reproducible from fill to fill • The matched point distribution was improved by eliminating some points above 1.5 m and by allowing different β* values in the IPs ~120 mm J.Wenninger S. Redaelli

  9. Commissioning (optics) Optics measurements and corrections @4 TeV Around 20% peak beta-beating at flatop (very similar to 3.5 TeV machine) Beta beat at 0.6 m reducedfrom 90/100% to 7% in both beams

  10. Commissioning(collisions) V plane 100s 40s 220s 40s H plane 220s 100s Separation bumps Xing bump IR8: from H to V Xing Before FF Before FF 100 mm 100 mm After FF After FF 100 mm 100 mm

  11. outline Commissioning Cycle – operation Cycle @~7 TeV Conclusions

  12. Cycle @4 TeV FLATOP Current (A) RAMPDOWN SETUP SQUEEZE ADJUST RAMP PREPARE RAMP INJECTION PROBE INJECTION PHYSICS STABLE BEAMS… RB.A12 RQ6.L1 Time

  13. Analysis method • Homogeneoussetoffills(onlyphysicsfillswith 1092/1380 bunches, 0.6m β* in IP1/5) • ‘Rampdown’ & ‘setup’ not takenintoaccount • Time calculationfor beam modes(tools: logging DB, PM, logbook) This analysis is not meant to evaluate the efficiency of the machine but rather the performance of operation in the hypothetical case of 100% availability

  14. INJECTION WHAT WE DO • Inject the pilots and set up the beams • Fill the machine • Remove the injprotection COLL • Close the injection handshake

  15. PREPARE RAMP WHAT WE DO • Set up and switch ON the fbs • Settings incorporation • FGC+COLL functions load

  16. RAMP WHAT WE DO • Ramp • Incorporation (in the shade)

  17. FLATOP WHAT WE DO • Tunes check (RQTD/F currents) • Settings incorporation • FGC+COLL functions load

  18. SQUEEZE WHAT WE DO • Squeeze • Orbit fb OFF

  19. ADJUST WHAT WE DO • Bring the beams into collisions (LHCb tilting) • IPs optimization (sometimes)

  20. Cycle @4 TeV 36 min Unless differently specified, values are in seconds * length of the BP removed

  21. outline Commissioning Cycle – operation Cycle @~7 TeV Conclusions

  22. Cycle @(~)7 TeV • Operational cycle at 6.5 TeV • Injection at 11 m • Ramp to 6.5 TeV(1250 s) • Squeeze to 40/45 cm β* (1473 s –calculated for 55 cm) • Collisions (270 s tilting LHCb) • itshouldbe possible to go without the tilting if we have vertical crossing all along • Rampdown(~4200 s)

  23. Cycle @(~)7 TeV 51 min Unless differently specified, values are in seconds *calculated by adding replacing the estimated 2015 BP length to the 2012 values

  24. Cycle @(~)7 TeV • We have many possibility: • some of them would make the cycle shorter: • Ramp & Squeeze • Beta* levelling • Low beta (5/7 m) injection (90 m for highbeta) • Some would have no effect on time • Colliding & squeezing • ATS vs standard optic • Flat beams • 25 ns

  25. Cycle @(~)7 TeV MOST AGGRESSIVE SCENARIO: • Injection at 5 m (with collision tunes) • Ramp & Squeeze to 6.5 TeV / 1 m (1250 s) • Collisions without LHCb tilting (~100 s) • Beta* levelling from 1 m

  26. Cycle @(~)7 TeV 29 min Unless differently specified, values are in seconds

  27. Cycle @(~)7 TeV Thanks to FIDEL team

  28. Cycle @(~)7 TeV Thanks to FIDEL team

  29. Conclusions • 2012 commissioning was successful (first SB in 22 days!) – the machine was very similar to 2011 • On OP point of view we are approaching the limit time given by the settings, but we still can improve(flatop, rampdown,…) • Operation in 2012 was efficient and reproducible - despite the longer settings, the cycle was in average 36 min faster than in 2011 (big gain at injection) • The OP cycle at 6.5 TeV would take ~51 min (37%) more time than at 4 TeV • This can be reduced (up to ~29 min - 15%) • In order to properly prepare the 2015 operation we should converge on a possible scenario by mid 2013 • As baseline we propose to start with the same (type of) cycle as 4 TeV (well known!), then have a stop point around mid 2015 to steer the strategy

  30. SPARE SLIDES

  31. Commissioning(450 GeV) • Orbit of the flat machine was re-corrected, first against 2011 reference, then some absolute corrections were applied: • Orbit was found to be very similar to 2011 ref (0.2 - 0.3 mm rmsdifference) 0.47 mm 0.39 mm 0.36 mm 0.33 mm Optics measurements and corrections @450 GeV Beta-beating down to 5-10% from 30-40% Normalized H dispersion beat reduced from 0.04m1/2 to 0.01m1/2 B2 B1

  32. Commissioning (optics) Optics measurements and corrections @450 GeV Beta-beating down to 5-10% from 30-40% Normalized H dispersion beat reduced from 0.04m1/2 to 0.01m1/2 B1 B2

  33. SB & turnaround MEAN = 6 h 34 min MINIMUM = 2 h 8 min 24 s

  34. Commissioning (squeeze) Fill 2306 (Nov 2011) - r.m.swrt first orbit (arc) Ex: B1 50 mm ~120 mm With parabolic round-off 100 mm Fill 2534 50 mm After feed-forward The optimization can be further improved during LS1 to get less transient orbit spikes

  35. Cycle at 4 TeV Thanks to FIDEL team

  36. Commissioning (problems) • Glitch on the safe beam flag (noise on BCT2B giving values above the safe beam limit) • Intermittent interlock on BMPSA.4R6.B2 • Vacuum gauge outgassing between Q6 and Q5.L5 • Issue with generation of the functions for trim quadrupoles (some points were too close after incorporation) • Problem with the bunch placement on the MKI waveform • FGC: • A bug was found in the FCG software that ignored the real-time correction • Tweak on the current reference that was following the measured current

  37. Rampdown RQX.R5 W.Venturini RQD.A56 RQ4.R2 4min max

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