1. Status of the LHC December 2009
R. Bailey
CERN

2. 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

3. 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

4. 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

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

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

7. 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

8. 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

9. 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

10. 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 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 – Q (nQPS)
Pressure relief valves installed everywhere possible Q1 – Q (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

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

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

13. Evolution of target energy during commissioning
When
Why
Target energy
7 TeV
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

14. 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 kA (OK for 1.18 TeV)
7 TeV
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

15. 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

16. January February 2010
11/14/2018

17. Installation of protection systems Hardware commissioning to 2kA
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)

18. 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

19. 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)

20. Cryogenics availability
11/14/2018

21. 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 → at 1.1 TeV
LIMITS
2 on 2 with per bunch at 1.1 TeV
4 on 4 with per bunch at 1.1 TeV

22. 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

23. 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

24. 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

25. 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

26. Threading from 2 to
11/14/2018

27. First turns
11/14/2018

28. Phase loop
Without
11/14/2018
With Loop On

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

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

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

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

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

34. Q Q’ C and Q loop
11/14/2018

35. Radial modulation for Q’ measurements
11/14/2018

36. Aperture scans – IR5 H shown
11/14/2018

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

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

39. Steering at the IPs
11/14/2018

40. Stable beams with 4 on 4
11/14/2018

41. Production !
11/14/2018

42. Injecting 16 on 16
11/14/2018

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

44. 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

45. 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 TeV 450 GeV
ALICE: 40k 33k ~400k ( 13k +/+ 120k 0/- dip/sol
180k -/ k -/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

46. LHCb event at 900 GeV
11/14/2018

47. ALICE event at 900 GeV
11/14/2018

48. Particle physics !
11/14/2018

49. CMS event at 2.36 TeV
11/14/2018

50. ATLAS event at 2.36 teV
11/14/2018

51. 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

52. 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

53. 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

54. LHC nominal performance
Nominal settings
Beam energy (TeV)
7.0
Number of particles per bunch
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

55. 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

56. 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

57. 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

58. 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 !

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

60. Higher intensities With experience assume that we can
Move to tight settings
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

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

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

63. 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

64. 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

65. 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

66. 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

67. 2010 run / part I 3-4 months Energy limited to 3.5TeV
Stabilizers
Intensity limited to (20% nominal)
Collimator cleaning efficiency at intermediate settings
 *
Aperture
limited to 2m without crossing angle
limited to 3m with crossing angle
11/14/2018

68. 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

69. 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

70. 2010 run / part II 3-4 months Energy limited to 5TeV
Stabilizers
Intensity limited to (10% nominal)
Collimator cleaning efficiency at intermediate settings
 * limited to 2m
Aperture
11/14/2018

71. 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

72. 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