Status and Outlook of the LHC

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2 Status and Outlook of the LHC Enrico Bravin - CERN BE-BI J-PARC visit seminar 6 July 2017

3 Outlook Overview of LHC Objectives for run2 Parameters for 2016/2017 and differences w.r.t Summary of commissioning and operation Performance and achievements of 2016 and 2017 Peek at 2018 and beyond 3

4 The Large Hadron Collider Double ring of 27 km circumference Twin aperture superconducting magnets Designed to collide protons (and heavy ions) at high energy (7 TeV) and high luminosity (10 34 cm -2 s -1 ) 4 interaction points LHC energy limited to 6.5 TeV by the need to retrain the magnets 200 quenches were needed to reach 6.5 TeV 300 more will be needed to reach 7 TeV (postponed 2020) 4

5 LHC and injectors Protons Linac-2 50 MeV Booster 1.4 GeV PS 25 GeV SPS 450 GeV LHC 7 TeV 208 Pb 82+ Linac MeV/u LEIR 72 MeV/u PS 5.9 GeV/u SPS 177 GeV/u LHC 2.76 TeV/u 5

6 Beam parameters L = N 2 b f revk b 4 " 1 q 1+( xing s ) 2 2 xing Run 1 Run Design Energy [TeV] Ibunch 1.7E E E E E E+11 Bunch spacing [ns] / Beta* [m] *33 55 Crossing angle [urad] / / # of bunches Emittance [mm mrad] Peak Luminosity [cm -2 s -1 ] 7.7E+33 5E E+34 *1.7E34 *1.9E34 1E+34 Integrated Luminosity [fb-1] *45 *45 6

7 Objectives for Run 2 Run 2 main objective: 100 fb -1 p-p for ATLAS and CMS at E cm 13TeV 2015: Recommission the machine after LS1 at E beam = 6.5TeV Target 5 fb : p-p production + Pb-p run Target p-p 25 fb : p-p (+ Pb-Pb in 2018) Target p-p 45 fb -1 /y 7

8 Changes Smaller beta* from 80cm to 40cm higher luminosity New combined ramp & squeeze (3m) shorter cycle Better handling of e-cloud effects mitigate transients, reduced movement of triplet in IR8 Changed BLM thresholds minimise dumps due to UFOs BCMS beams smaller transverse emittances higher luminosity 8

9 Changes Replaced one superconducting dipole, thermal cycle of sector 12, potential e-cloud and UFO surge New optics (Achromatic Telescopic Squeeze) potential for beta* < 40 cm (HL-LHC baseline optics) Dynamic crossing angle during the fill 300 to 240 urad higher luminosity Improved combined ramp & squeeze (1m) shorter cycle Fixed limitations with SPS and injection kicker vacuum longer bunch trains (144 bpi, more bunches) and higher bunch intensity, higher L 9

10 Beam commissioning 3 phases 1. Low intensity single bunch (8E9 protons) 2. Nominal intensity single bunch (1.2E11 protons) 3. Gradual increase of number of bunches (1-2500) 10

11 Commissioning milestones 2017 EYETS - Many interventions warm-up of S12 Ended on April 14 Nominal intensity Injection Started operation with nominals May 4 Powering tests Start March 31 End April 26 Combined ramp and squeeze CR&S on May 12 HW check out BIS loop closed April 28 Squeeze First collisions First collisions May 12 Low intensity injection Low intensity combined ramp and squeeze First beam April 29 First CR&S to 1m April 30 Collimators setup First stable beams Bunch trains injection May 23 3b+3b May 24 12b+12b 72b May 26 Low intensity squeeze First squeeze to 40cm May 1 Physics Intensity ramp-up 2029b June 20 Corrections of Optics, Q, Q`, C - 11

12 Combined Ramp & Squeeze CR&S Squeeze 11m 10m ALICE 6m Beta* [dm] m m LHCb 40cm ATLAS & CMS 12

13 Possible performance limitations Unidentified laying object (ULO) Reduces available aperture Unidentified falling objects (UFO) Trigger beam dumps and magnet quenches Electron cloud Limits number of bunches (vacuum, thermal load) Instabilities: losses, degraded beam quality Hardware faults rate Fault tracking tools (identify critical systems) Consolidations (using fault tracking as input) R2E project (SEU almost gone) 13

14 UFOs Small particles (~10μm) falling onto the beam generating showers Source and mechanism not fully understood yet 2015: 21 UFO-related dumps, including 3 quenches (ULO events not included) In 2016 increased threshold of BLMs Expected increase of UFO-induced quenches (~+1) Expected decrease of UFO-induced dumps(~-10) 2016: 21 UFO-related dumps including 3 quenches 14

15 Evolution of UFOs There is a clear conditioning effect Not known if conditioning will be lost after venting At the present rate UFOs are under control Time 15

16 Electron cloud Electron liberated on the vacuum chamber are accelerated by the p+ beam Accelerated electrons impact on the vacuum chamber liberating more electrons If the SEY is high, and the bunch spacing short, it turns into an avalanche producing heat load on the cold beam screens and trigger beam instabilities electron bombardment reduces the SEY (scrubbing) 16

17 e-cloud in 2016 Modest effects of e-cloud during 2016 due to the limitation in bunch current and short batches Cryo limit 160 w/hc Courtesy G. Iadarola 17

18 e-cloud in 2017 Scrubbing run 18

19 Sector 1-2 back where it was in 2016 Friday Sunday 19

20 Availability 6 June 18 September Excellent availability! Almost 50% of fills dumped by OP Courtesy B. Todd 20

21 Fault analysis 21 Courtesy B. Todd

22 Other limitations in 2016 Start of the run affected by few important faults Some generated long downtimes 66kV transformer IP8, POPS, PS MPS, water flooding Pt.3 Some imposed limitations throughout the year LHC dump B1 N2 leak (in the shadow of other limitations) SPS internal dump (TIDVG) (no 144b/288b trains) Bad vacuum around injection kicker of B2 max total current for B2 limited to ~2.4E14p (e-cloud) 14 April - LHC dump B1 25 April - SPS dump 27 April POPS down 29 April marteen 20 May - PS MPS 21 June - Water Pt. 3 22

23 Standard vs BCMS beams in the PS Standard 72b batch εxy~2.5μm Ibunch < 1.3E11 BCMS 48b batch εxy~1.5μm Ibunch < 1.3E11 23

24 Beam structure The LHC injection gap is ~900ns while the SPS injection gap is ~200ns The maximum number of bunches in the LHC depends on the number of batches per SPS injection 72b / inj. max 2040b (2 x 48b) / inj. max 2220b (2076b) (4 x 72b) / inj. max 2800b PS batch 72b SPS batch 288b SPS batch 144b 3μs Abort gap 26.7km, 89μs, ns slots, max 2800 bunches 24

25 LHC performance MJ/beam Steady production from beginning of June From end of June LHC operated consistently above design peak luminosity 25

26 Production 2016 Astonishing integrated luminosity achievement Fast ramp-up after each configuration change Steady peace through the year 26

27 Operation cycle Turnaround 3h is technically the shortest value Almost half of the fills ended by operators We can finally decide the length of fills! Courtesy B. Todd 27

28 Heavy ion run 2016 summary p - 5 tev c.m. for ALICE Very long fills at levelled luminosity Record fill of 37 hours in stable beams p - Pb and Pb - 8 TeV c.m. Increased bunch intensity of ions and protons Peak luminosity of 8E29 cm -2 s -1, a factor 7.8 better than design 28

29 HI run 2016 goals and results 29

30 LHC as tide and earth quake monitor LHC orbit 13: CET The long and fills at 4 TeV provided a unique opportunity to monitor the earth tides with the LHC during a week around full moon. The model scale is defined by LEP data scaled to LHC. New Zealand 7.8 MW earthquake of 11: UTC clearly visible 30

31 Special operation Van der Meer scans for luminosity calibration Full VdM scans on 17, 18, 27 May for all experiments Partial scans and studies here and there Large beta* run for forward physics (ALFA and TOTEM) September, very successful Plus many ad hoc cycles during the 20 days of MDs Partially with HL-LHC in view, partially to test improvement already applied 31

32 ~ Same days of p-p physics

33 Status of 2017 run Max 1.58 E34 cm -2 s -1 ~6.5 fb -1 33

34 Long term LHC plan 34

35 Conclusions Despite some troublesome events 2016 has been a wonderful year at the LHC Excellent machine availability/reliability as never before UFO, e-cloud, faults under control Despite not pushing parameters too hard due to limitations delivered more than 40fb-1 to ATLAS and CMS Big progress in understanding and controlling the machine Fast start-up in 2017 shows that the machine, the people and the tools are mature Peak luminosity of 2016 already surpassed after only few weeks of physics in 2017 Established a solid base for the coming years 35

36 The End

37 Commissioning milestones 2016 YETS - Many interventions on many systems Ended on March 4 Nominal intensity Injection Started operation with nominals March 29 Powering tests HW check out Low intensity injection Low intensity combined ramp and squeeze Low intensity squeeze Corrections of Optics, Q, Q`, C - Start March 4 End March 21 BIS loop closed March 23 First beam March 25 First CR&S March 26 First squeeze March 26 Combined ramp and squeeze Squeeze First collisions Collimators setup First stable beams Bunch trains injection Physics Intensity ramp-up CR&S on April 6 First collisions April 8 April 23 3b+3b April 24 12b+12b 72b April b June 1 Included special bump in IP5 to increase dispersion in TOTEM 37

38 e-cloud studies Several fills with same conditions during the year to quantify conditioning (modest) 3 fills with 72bpi and increasing bunch intensity Large differences between sectors not understood 38

39 Radiation effects Beam Losses Distance from IP1 (cw) [m] Courtesy S. Danzeca 39

40 Not only ATLAS and CMS ALICE ~13.5 nb -1 LHCb ~1.9 fb -1 Both profit from the long fills 40

41 Luminosity lifetime h turnaround ATLAS 72b 3.0μm 185μrad 96b 2.5μm 185μrad 96b 2.5μm 140μrad CMS Courtesy F.Antoniou, G. Iadarola, Y.Papaphilippou 41

42 Losses in collisions May October 140 μrad During the first few hours in collisions losses well in excess of the burn-off After ~3h losses become dominated by luminosity burn-off Situation improved during the year (BCMS) Courtesy F.Antoniou, G. Iadarola, Y.Papaphilippou Reduction of crossing angle has no effect 42