Status of the LHC December 2009 R. Bailey CERN

Status of the LHC Construction Commissioning Consolidation The problem and fixing it Understanding the problem Progress with beam 2009 Performance drivers Making sure there is no Titanic II Prospects for 2010 Prospects for 2009 2010

cryogenics and powering Schematic of the LHC RF system Beam extraction 8 distinct sectors for cryogenics and powering collimators collimators injection beam 1 injection beam 2 2.9km transfer line 2.7km transfer line

Construction Commissioning Consolidation 2002-09 Tunnel activity determined by LEP Helium Distribution Line Triplet Cryo S34 2002 2003 2004 2005 2006 2007 2008 2009 All magnet tested to 7TeV Machine-wide S34 Repair protection and PC SC tests Definitive cooldown and commissioning for 5TeV Beam Magnet installation Required magnet storage  Allowed magnet sorting  Magnet interconnects While not forgetting Injection systems Extraction systems RF systems Collimation systems Vacuum systems Beam instrumentation systems Machine protection systems Controls Experiments Beam Sector 78 commissioning Sector 45 commissioning 11/14/2018

September 19 – source of the problem 1232 dipoles, 392 dipoles, 6 high current splices each

Arc and helium released to insulating vacuum Liquid to Gas Expansion Factor 1000

Pressure wave travelled along accelerator Self actuating relief valves opened but could not handle all (DN90) (DN90) 50m 100m 50m Q23 Q24 Q25 Q26 Q27 Large forces exerted on vacuum barriers located every 2 cells Connections to cryogenic line also affected in several places Beam vacuum system also affected

Extent of damage and necessary repair Had to treat to lesser or greater degree all magnets Q19 to Q33 as shown 53 had to be brought to the surface (39 dipoles and 14 quads) Replaced with spare or refitted, then retested and reinstalled Huge enterprise; last magnet back in mid April Not forgetting cleaning the beam pipes Then have to align, make all interconnections, cool down, power test

LHC Interconnects Superconductor Solder Copper stabilizer Current flow at 1.9K Good joint resistance < 1 nΩ Current flow after a quench Good joint resistance < 10 µΩ

Machine wide activities Q4 2008 and 2009 Sector 34 repair Restart Q4 2008 Q1 2009 Q2 2009 Q3 2009 Q4 2009 Calorimetric and electrical splice measurements everywhere at cold (measuring nΩ) Q4 2008 Had to warm up sectors 12 67 to exchange magnets (and 56 for other reasons) Electrical stabilizer measurements everywhere at warm or at 80K (measuring µΩ) Q1 - Q3 2009 Had to warm up sector 45 Major new protection system based on electrical measurements Q1 – Q4 2009 (nQPS) Pressure relief valves installed everywhere possible Q1 – Q3 2009 (dipoles have to be warm) Reinforcement of floor anchors everywhere Q1 – Q3 2009 Q4 2008 Q1 2009 Q2 2009 Q3 2009 Q4 2009 12 Cold Cold  Warm Warm Warm  Cold 23 < 100K < 100K  Cold Cold  80K  Cold 34 45 80K  Warm 56 67 78 < 100K  80K 80K  Cold 81

Periodic cooling for resistivity measurements Cryogenics Q4 2008 to Q2 2009 Warm-up for repairs Periodic cooling for resistivity measurements 11/14/2018

Cryogenics Q3 and Q4 2009 Cool-down from 300K in 4-5 weeks per sector (target), and relatively good stability @ 1.9 K thereafter 11/14/2018

Evolution of target energy during commissioning When Why Target energy 7 TeV 2002-2007 Design Current (with margin) 12 kA 5 TeV Summer 2008 Detraining 9 kA Late 2008 Splices 3.5 TeV Summer 2009 Stabilizers 6 kA 1.18 TeV October 2009 nQPS 2 kA 450 GeV 11/14/2018

A bit more detail When Why 7 TeV 2002-2007 Design 5 TeV Summer 2008 All main magnets commissioned for 7TeV operation before installation Detraining found when hardware commissioning sectors in 2008 Easy to get to 5TeV Harder to get to 6TeV Even harder to get to 7TeV Machine wide investigations following S34 incident showed problem with spices (OK for 5 TeV) Machine wide investigations following S34 incident showed problem with stabilizers (OK for 3.5 TeV) Commissioning of new QPS system in 2009 Breakdown at operational voltage – connector quality Obliged to run at lower voltage on this system Need to change thousands of connectors Incurred delays in commissioning to 6kA Target for 2009 2kA (OK for 1.18 TeV) 7 TeV 2002-2007 Design 5 TeV Summer 2008 Detraining 9 kA Late 2008 Splices 3.5 TeV Summer 2009 Stabilizers 6 kA 1.18 TeV October 2009 nQPS 2 kA 11/14/2018

The way back When What Train magnets Fix stabilizers for 12kA Should be easy to get to 6TeV 6.5 TeV and 7 TeV will take time Fix stabilizers for 12kA Machine wide Do it in 2 shutdowns ? Commission circuits to 9kA Based on experience gained Not at all guaranteed ! Fix connectors and commission circuits to 6kA 7 TeV 2014 ? Training 6 TeV 2012 ? Stabilizers 5 TeV Summer 2010 9 kA 3.5 TeV January and February 2010 nQPS 6 kA 11/14/2018

January February 2010 11/14/2018

Installation of protection systems Hardware commissioning to 2kA 2009 2010 2009 2010 Repair of Sector 34 Installation of protection systems Hardware commissioning to 2kA M C O 1.18 TeV 6 kA 3.5 9 5 Ions Shut down No Beam B NB Beam Ions 2009 Main circuits commissioned to 2kA for 1.18 TeV Commissioning with beam (450 GeV collisions and ramp to 1.18 TeV) 2010 Fix connectors and commission circuits to 6kA for 3.5 TeV beam Physics at 7 TeV com (few months) Commission circuits to 9kA for 5TeV beam (not at all guaranteed !) Physics at 10 TeV com (few months) Ion run (2 weeks to set up then 2 weeks physics)

Status of the LHC Construction Commissioning Consolidation The problem and fixing it Understanding the problem Progress with beam 2009 Performance drivers Making sure there is no Titanic II Prospects for 2010 Prospects for 2009 2010

Power test summary (November 18) This is for powering each of the ~1500 circuits individually Roughly twice as fast as 2008 (for ~same number of tests) Included commissioning new QPS Huge effort by many people (thanks to everyone concerned) Machine handed over to Operations November 18 Still have to power all circuits together Still a few things to sort out (but could take beam at 450GeV) Still have to make Global Machine Checks (2 days)

Cryogenics availability 11/14/2018

Targets with beam 2009 1.18 TeV 2 kA 450 GeV AIMS 450 GeV collisions 106 events Ramp to 1.18 TeV Collisions at 1.18 TeV Do this with SAFE BEAMS 1012 at 450 GeV → 2 1011 at 1.1 TeV LIMITS 2 on 2 with 5 1010 per bunch at 1.1 TeV 4 on 4 with 2 1010 per bunch at 1.1 TeV

Diary November 2009 Date Day Up Down Achieved Nov 20 Fri 5 Beam 1 circulate and capture. Beam 2 circulate and capture Nov 21 Sat 15 9 Splash data. RF tuning B1. BI commissioning. Q Q’ C B1. Nov 22 Sun 8 16 Kick-Response campaign started. Optics studies started. Nov 23 Mon 24 RF Q Q’ C B2. Lifetimes B1 B2 now 10h. First collisions. First ramp B1. Nov 24 Tue 6 18 Aperture measurements arcs started. Access and recovery. Nov 25 Wed 2 22 Revisit Q Q’ C both beams. Magnetic cycling available sectors. Nov 26 Thu Magnetic cycling established. Optics studies. Nov 27 3 21 K-R. Energy matching done. Nov 28 K-R. Beam dump set up. Protection elements. BI commissioning. Nov 29 Optics. Collimator first set up. Ramp to 1.18 TeV. Nov 30 Solenoids on and compensated. 11/14/2018

66% availability for operations Diary December 2009 Date Day Up Down Achieved Dec 01 Tue 19 5 BI commissioning. Aperture arcs and K-R. Beam dump. Cogging. Dec 02 Wed 3 21 Electrical power and cryogenic problems. MPS checks. Dec 03 Thu 24 Aperture IRs. Optics. Injection protection. Beam dump. BI. Dec 04 Fri 17 7 Separation bumps. Crossing angles. MPS checks. Aperture. Dec 05 Sat LHCb, ALICE on. References. Collimation. Beam dump. Injection. MPS OK. Dec 06 Sun 4 bunches in 2 beams. Collisions with Stable Beams at 450GeV. Dec 07 Mon 2 22 Cryogenic (temperature alarm) and Electrical problems. Dec 08 450 GeV Collisions. Intensity studies. Ramp colliding bunches to 1.18 TeV. Dec 09 450 GeV Collisions with LHCb off (short). Intensity transfer lines, injection. Dec 10 23 1 450 GeV Collisions (short). Intensity dump, collimators. SL monitor. Dec 11 Collisions Stable Beams at 450 GeV, higher intensity Dec 12 Collisions Stable Beams at 450 GeV Dec 13 Ramp 2 bunches per beam to 1.18TeV. Collisions for 90mins at 1.18 TeV. Dec 14 16 8 16 on 16. Separation bumps on. Collisions Stable Beams at 450 GeV. Dec 15 18 6 TOTEM. Abort Gap. Orbit feedback. Ramp. Dec 16 12 4 Ramp. Squeeze IR 5 to 7m. Optics measurements. TOTAL 407 214 66% availability for operations 11/14/2018

Milestones reached Date Day Achieved Nov 20 1 Each beam circulating. Key beam instrumentation working. Nov 23 4 First collisions at 450 GeV. First ramp (reached 560 GeV). Nov 26 7 Magnetic cycling established (reproducibility). Nov 27 8 Energy matching done. Nov 29 10 Ramp to 1.18 TeV. Nov 30 11 Experiment solenoids on. Dec 04 15 Aperture measurement campaign finished. LHCb and ALICE dipoles on. Dec 05 16 Machine protection (Injection, Beam dump, Collimators) ready for safe operation with pilots. Dec 06 17 First collisions with STABLE BEAMS, 4 on 4 pilots at 450 GeV, rates around 1Hz. Dec 08 19 Ramp colliding bunches to 1.18 TeV Dec 11 22 Collisions with STABLE BEAMS, 4 on 4 at 450 GeV, > 1010 per bunch, rates around 10Hz. Dec 13 24 Ramp 2 bunches per beam to 1.18 TeV. Collisions for 90mins. Dec 14 25 Collisions with STABLE BEAMS, 16 on 16 at 450 GeV, > 1010 per bunch, rates around 50Hz. Dec 16 27 Ramp 4 on 4 to 1.18 TeV. Squeeze to 7 m. Collisions. 11/14/2018

Ramps Date Day Ramp Beam 1 Beam 2 Nov 23 4 1 Bare ramp. Reached 560 GeV Nov 29 10 2 Bare ramp. Reached 1.04 TeV 3 Tunes fed forward. Reached 1.18 TeV Bare ramp. Reached 1.18 TeV Dec 08 19 Tunes as before. Reached 1.18 TeV Q loop on. Reached 1.18 TeV Dec 13 24 5 Q loop on. Lost at 800 GeV (interlock) 6 Dec 15 26 7 Clean ramp. Reached 1.18 TeV Dec 16 27 8 Clean ramp. Squeeze to 7m 11/14/2018

Threading from 2 to 3 5 6 7 8 1 11/14/2018

First turns 11/14/2018

Phase loop Without 11/14/2018 With Loop On

Injection 11/14/2018 P2, overinjection: no interlock

Beam dump IR6 H Beam2, extracted IR6 H Beam2, circulating 11/14/2018

Dump protection tests Asynchronous dump tests, 4 bunches Beam1 losses TCDS Beam2 debunched beam TCDQ TCP IR7 Beam2 losses TCDS TCDQ 11/14/2018

Collimation after beam based set up (Ralph) Efficiency: > 99.9% 11/14/2018

Collimators – provoked beam loss on resonance 11/14/2018

Q Q’ C and Q loop 11/14/2018

Radial modulation for Q’ measurements 11/14/2018

Aperture scans – IR5 H shown 11/14/2018

First ramp that went to 1.18 TeV 11/14/2018

Beta-beat comparison 450 GeV and 1.18 TeV 11/14/2018

Steering at the IPs 11/14/2018

Stable beams with 4 on 4 11/14/2018

Production ! 11/14/2018

Injecting 16 on 16 11/14/2018

Test dump of 16 bunches per beam 11/14/2018

Optimum data rates 2009 Energy TeV 0.45 1.18 Bunch intensity 1.E+10 1 Bunches per beam (colliding) 4 (2) 16 (8) Emittance µm 3.75 β* m 11 Beam size in 1 and 5 um 293.3 181.1 Luminosity in 1 and 5 cm-2 s-1 5.2E+25 8.3E+26 3.3E+27 2.2E+27 Total inel cross section cm2 4.0E-26 Event rate Hz 2.1E+00 3.3E+01 1.3E+02 8.7E+01 11/14/2018

Data recorded “stage” Total hours 4x4 5e9 p/bch 16 hrs Estimated numbers of pp interactions recorded by experiments NOT STABLE BEAMS IN STABLE BEAMS (detectors partly on) (full detector on, with preliminary bkgd subtraction) 450 GeV 1.18 TeV 450 GeV ALICE: 40k 33k ~400k ( 13k +/+ 120k 0/- dip/sol 180k -/- 81k -/0 ) ATLAS: ~320k ~34k ~540k (of which 220k not nominal fields) CMS: ~110k ~18k ~410k (of which 60k not nominal field) LHCb: ~40k ~250k (of which ~3k with dipole off) LHCf: ~6k showers TOTEM: numbers to come 11/14/2018

LHCb event at 900 GeV 11/14/2018

ALICE event at 900 GeV 11/14/2018

Particle physics ! 11/14/2018

CMS event at 2.36 TeV 11/14/2018

ATLAS event at 2.36 teV 11/14/2018

Summary of progress with beam 2009 Excellent machine availability Excellent performance of all accelerator systems Huge amount achieved in 4 weeks All targets met and more Plenty to think about Great collaboration between machine and experiments Looks promising for 2010 11/14/2018

Status of the LHC Construction Commissioning Consolidation The problem and fixing it Understanding the problem Progress with beam 2009 Performance drivers Making sure there is no Titanic II Prospects for 2010 Prospects for 2009 2010

Instantaneous luminosity “Thus, to achieve high luminosity, all one has to do is make (lots of) high population bunches of low emittance to collide at high frequency at locations where the beam optics provides as low values of the amplitude functions as possible.” PDG 2005, chapter 25 Nearly all the parameters are variable (and not independent) Number of particles per bunch  Number of bunches per beam kb Relativistic factor (E/m0)  Normalised emittance n Beta function at the IP  * Crossing angle factor F Full crossing angle c Bunch length z Transverse beam size at the IP * Intensity Energy Interaction Region 11/14/2018

LHC nominal performance Nominal settings Beam energy (TeV) 7.0 Number of particles per bunch 1.15 1011 Number of bunches per beam 2808 Crossing angle (rad) 285 Norm transverse emittance (m rad) 3.75 Bunch length (cm) 7.55 Beta function at IP 1, 2, 5, 8 (m) 0.55,10,0.55,10 Derived parameters Luminosity in IP 1 & 5 (cm-2 s-1) 1034 Luminosity in IP 2 & 8 (cm-2 s-1)* ~5 1032 Transverse beam size at IP 1 & 5 (m) 16.7 Transverse beam size at IP 2 & 8 (m) 70.9 Stored energy per beam (MJ) 362 * Luminosity in IP 2 and 8 optimized as needed 11/14/2018

LHC performance drivers Intensity Collimation Injector chain Electron cloud effect Machine protection Nominal Start Energy Interconnects Training Machine protection Interaction region (β*, F) Optics Aperture Machine protection 11/14/2018

Energy already discussed When What Train magnets Should be easy to get to 6TeV 6.5 TeV and 7 TeV will take time Fix stabilizers for 12kA Machine wide Do it in 2 shutdowns ? Commission circuits to 9kA Based on experience gained Not at all guaranteed ! Fix connectors and commission circuits to 6kA 7 TeV 2014 ? Training 6 TeV 2012 ? Stabilizers 5 TeV Summer 2010 9 kA 3.5 TeV January and February 2010 nQPS 6 kA 11/14/2018

Significant to begin with Expected to improve with time Intensity Collimation system conceived as a staged system First stage to allow 40% of nominal intensity at 7 TeV Under certain assumptions of LHC lifetimes and loss rates With ideal cleaning Imperfections bring this down Deformed jaws Tilt and offset and gap errors Machine alignment Machine stability and reproducibility also play a role Tight settings will be a challenge early on Intermediate settings make use of aperture to relax tolerances Cleaning gets easier at lower energies 0.1%/s assumed Lifetime dip to 0.2h Significant to begin with Expected to improve with time 11/14/2018

Intensity v loss rate, 7 TeV, with imperfections 10% 2% 11/14/2018 IF we were running at 7TeV in year 1, intensity would be very limited !

Intensity limits 2010 0.2%/s assumed Fix Imax to 6 1013 protons per beam at 3.5TeV (about 20% nominal intensity) Assume 2-3 1013 protons per beam at 5TeV (about 10% nominal intensity) 30MJ stored beam energy in both cases 11/14/2018 11/14/2018

Higher intensities With experience assume that we can Move to tight settings 5 1013 at 5TeV under same assumptions as before About 20% of nominal intensity Achieve 0.1% loss rates 1014 at 5 TeV (30% of nominal) Get the imperfection factor down Factor 2-3 (75% of nominal at 5 TeV) Then need to install something more Proposal exists for next phase of collimation Collimators in the cold regions of the machine Using “missing magnet” space in the dispersion suppressors Requires moving magnets in LSS3 and LSS7 (24 magnets each) 11/14/2018

Interaction Region - β* IP Injection 11m Low β at the IP, high β in nearby quadrupoles Physics 0.55m 11/14/2018

Interaction Region - F With > 150 bunches per beam, need a crossing angle to avoid parasitic collisions 11/14/2018

β* and F in 2010 Lower energy means bigger beams Less aperture margin Higher β* > 150 bunches requires crossing angle Requires more aperture Targets for 3.5TeV 2 m without crossing angle 3m with crossing angle Targets for 5TeV 2m 11/14/2018

β* evolution As energy increases, lower β* gets easier The squeeze is always going to be challenging Changing optics with dangerous beams Follow / anticipate with collimators Particularly tricky below 1m With experience, should be easier, but still … 11/14/2018

Status of the LHC Construction Commissioning Consolidation The problem and fixing it Understanding the problem Progress with beam 2009 Performance drivers Making sure there is no Titanic II Prospects for 2010 Prospects for 2009 2010

Integrated luminosities - a look back at LEP1 LEP1 statistics 1990 1991 1992 1993 1994 1995 scheduled for physics h 2504 2762 3439 2943 3175 3070 beam in coast 1048 1242 1742 1619 1871 1414 number of coasts 143 154 199 168 197 194 Coasts per day 1.37 1.34 1.39 1.49 1.52 average coast length 7.33 8.06 8.75 9.64 9.50 7.29 efficiency for physics (in coast/scheduled) % 41.85 44.97 50.65 55.01 58.93 46.06 Peak initial luminosity 1030 11.0 10.0 15.5 22.4 24.9 Integrated luminosity nb-1 12100 18900 28600 40000 64500 46100 Overall efficiency factor (integrated/scheduled*peak) 0.12 0.19 0.21 0.24 0.25 0.17 Expect to spend as much time out of physics as in physics Rampdown, injection, ramp, squeeze, prepare Faults, access, other problems If we average a 10h fill per day in 2010 we’ll be doing well (40% efficiency for physics) Overall efficiency factor Measure of how much physics we get from scheduled time with a given peak luminosity Includes all the time not in physics (as above) AND luminosity decay in coast If we get this up to 0.2 in 2011 we’ll be doing well (then steadily increase to 0.26) 11/14/2018

2010 run / part I 3-4 months Energy limited to 3.5TeV Stabilizers Intensity limited to 6 1013 (20% nominal) Collimator cleaning efficiency at intermediate settings  * Aperture limited to 2m without crossing angle limited to 3m with crossing angle 11/14/2018

2010 Performance at 3.5 TeV no crossing angle Energy TeV 0.45 3.50 Bunch intensity 1.E+10 4 9 Bunches per beam 2 (1) 12 43 156 Emittance µm 3.75 β* m 11 2 Luminosity in 1 and 5 cm-2 s-1 1.7E+27 2.0E+28 5.5E+29 3.0E+30 1.1E+31 5.5E+31 Total inel cross section cm2 4.0E-26 6.0E-26 Event rate Hz 1.0E+02 1.2E+03 3.3E+04 1.8E+05 6.5E+05 3.3E+06 Event rate / crossing 0.0 0.1 0.4 1.9 Protons 8.0E+10 1.7E+12 6.2E+12 1.4E+13 % nominal 0.5 4.3 Current mA 3.1 11.2 25.3 Stored energy MJ 1.0 3.5 7.9 Beam size in 1 and 5 um 293.3 105.2 44.8 Monthly integrated (0.1) pb-1 0.00 0.01 0.14 0.79 2.88 14.58 11/14/2018

2010 Performance at 3.5 TeV with crossing angle Energy TeV 3.50 Bunch intensity 1.E+10 9 7 Bunches per beam 156 144 288 432 720 792 Emittance µm 3.75 β* m 3 Luminosity in 1 and 5 cm-2 s-1 3.7E+31 2.1E+31 4.1E+31 6.2E+31 1.0E+32 1.1E+32 Total inel cross section cm2 6.0E-26 Event rate Hz 2.2E+06 1.2E+06 2.5E+06 3.7E+06 6.2E+06 6.8E+06 Event rate / crossing 1.3 0.8 Protons 1.4E+13 1.0E+13 2.0E+13 3.0E+13 5.0E+13 5.5E+13 % nominal 4.3 3.1 6.2 9.4 15.6 17.2 Current mA 25.3 18.1 36.3 54.4 90.7 99.8 Stored energy MJ 7.9 5.6 11.3 16.9 28.2 31.0 Beam size in 1 and 5 um 54.9 Monthly integrated (0.1) pb-1 9.54 5.33 10.66 15.99 26.65 29.31 11/14/2018

2010 run / part II 3-4 months Energy limited to 5TeV Stabilizers Intensity limited to 3 1013 (10% nominal) Collimator cleaning efficiency at intermediate settings  * limited to 2m Aperture 11/14/2018

2010 Performance at 5 TeV Energy TeV 5.00 Bunch intensity 1.E+10 4 7 9 Bunches per beam 156 144 288 432 360 Emittance µm 3.75 β* m 2 Luminosity in 1 and 5 cm-2 s-1 1.6E+31 4.9E+31 4.3E+31 8.6E+31 1.3E+32 1.8E+32 Total inel cross section cm2 6.0E-26 Event rate Hz 9.5E+05 2.9E+06 2.6E+06 5.2E+06 7.8E+06 1.1E+07 Event rate / crossing 0.5 1.6 2.6 Protons 6.2E+12 1.1E+13 1.0E+13 2.0E+13 3.0E+13 3.2E+13 % nominal 1.9 3.4 3.1 6.2 9.4 10.0 Current mA 11.2 19.6 18.1 36.3 54.4 58.3 Stored energy MJ 5.0 8.7 8.1 16.1 24.2 25.9 Beam size in 1 and 5 um 37.5 Monthly integrated (0.1) pb-1 4.11 12.60 11.19 22.39 33.58 46.26 11/14/2018

Summary LHC is up and running in 2009 Excellent performance with beam Limited in energy due to interconnects Superconducting splices and copper stabilizers Task force in place Chamonix meeting end of January The way forward for (the first part of) 2010 is clear Experience will then tell us what to do next 11/14/2018