LHC Status / View From CERN

1
LHC Status / View From CERN
(Roger Bailey)
(Mike Lamont)
CM13 in Port Jefferson 4. to 6. November 2009
Oliver Brüning/CERN AB-ABP 0
2
Machine wide investigations at cold Q4 2008

• Controlled calorimetric measurements at cold
  where possible
• Measured heat loads indicated problem areas
• Measure electrical resistance in suspect regions
• Electrical resistance of joints between and
  inside magnets
• Fix anything obviously very wrong (means warming
  up)

Q4 2008 Q4 2008
12 Cold
23 lt 100K
34 Warm
45 lt 100K
56 Cold
67 Cold
78 Cold
81 Cold
3
Calorimetric electrical measurement summary

• Made wherever possible in late 2008
• Sectors 23 34 45 already not cold
• Sectors 12 56 67 78 81 measured
• Identified 3 suspicious cases (in magnets)
• Sector 12 15R1 confirmed
• Sector 12 31R1 not confirmed
• Sector 67 31R6 confirmed

S34
4
Decisions Q1 2009
Sector 34 repair
Restart
Q4 2008 Q1 2009 Q2 2009 Q3 2009 Q4 2009

• Decided to warm up in 12 and 67 to replace faulty
  magnets
• Decided to warm up sector 56 in parallel for
  other reasons

Q4 2008 Q4 2008 Q1 2009
12 Cold Cold ? Warm
23 lt 100K lt 100K
34 Warm Warm
45 lt 100K lt 100K
56 Cold Cold ? Warm
67 Cold Cold ? Warm
78 Cold lt 100K
81 Cold lt 100K

• Warming up means
• 3 weeks to get to 300K
• Repair work
• ELQA and other issues
• 6 weeks to get back to 2K

5
Investigations in sector 34 Q1 2009
Bad surprise after gamma-ray imaging of the
joints Void is present in bus extremities
because SnAg flowed out during soldering of the
joint
6
Machine wide investigations Q2 2009

• Electrical measurements at warm on sectors 12 34
  56 67
• Confirms new problem with the copper stabilizers
• Non-invasive electrical measurements to show
  suspicious regions
• Several bad regions found
• Open and make precise local electrical
  measurements
• Several bad stabilizers found (30µO to 50µO) and
  fixed
• Measured other 4 sectors at 80K (noisy but gives
  limits)

7
Machine wide activities Q4 2008 and 2009
Sector 34 repair
Restart
Q4 2008 Q1 2009 Q2 2009 Q3 2009 Q4 2009

• Electrical splice measurements everywhere at cold
  (measuring nO) Q4 2008
• Had to warm up sectors 12 56 67
• Electrical stabilizer measurements everywhere at
  warm or at 80K (measuring µO) Q1 Q2 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 Q4 2008 Q1 2009 Q2 2009 Q3 2009 Q4 2009
12 Cold Cold ? Warm Warm Warm ? Cold Cold
23 lt 100K lt 100K lt 100K ? Cold Cold ? 80K ? Cold Cold
34 Warm Warm Warm Warm ? Cold Cold
45 lt 100K lt 100K 80K ? Warm Warm ? Cold Cold
56 Cold Cold ? Warm Warm Warm ? Cold Cold
67 Cold Cold ? Warm Warm Warm ? Cold Cold
78 Cold lt 100K lt 100K ? 80K 80K ? Cold Cold
81 Cold lt 100K lt 100K ? 80K 80K ? Cold Cold
8
Measurement summary Q3 2009

• 5 sectors measured at cold for splices
• 12 56 67 78 81
• Nothing above 40 nO remaining
• 23 34 45 not measured
• Data mining finds nothing gt 25 nO (in 99 of 23
  34 45)
• 5 sectors measured at warm for stabilizers
• 12 34 45 56 67
• All above 50µO fixed
• 23 78 81 measured at 80K
• Nothing above 90µO remaining

9
Energy

• Putting all this together
• Splices
• 5 TeV OK
• Stabilizers
• 3.5 TeV OK
• Higher energies needs operational experience to
  see which model variant most closely matches
  reality
• 90µO limit is very conservative
• Start at 3.5 TeV
• Operate
• Move to 5 TeV when experience allows it

10
Quench Protection System upgrade (nQPS)

• New QPS to provide
• Protection against symmetric quenches (problem
  noticed in summer 08)
• Local bus bar measurements capable of detecting
  bad splices
• Will also provide
• Precision measurements of the joint resistances
  at cold (sub-n? range) of every busbar segment
• complete mapping of the splice resistances (the
  bonding between the superconducting cables)
• The basic monitoring system for future
  determination of busbar resistances at warm
  (min. 80 K)
• measure regularly the continuity of the copper
  stabilizers
• Huge task
• Has to be working before repowering
  (recommendation of external review)
• On the critical path for restart
• Requires extensive testing

11
Cool down 2009
12
SD2 Conditions for working at height
SD1 Conditions for working at height
Access to ALICE subject to conditions
Access to ATLAS subject to conditions
SMI2 Conditions for working at height
13
M. Solfaroli Camillocci - Powering Tests
LHC-LMC 16/09/2009
General Schedule 9th, September 09
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Readiness of the sectors, late October
Sector 12 PO Phase II
Sector 23 PO Phase II
Sector 34 Cryo tuning
Sector 45 PO Phase I
Sector 56 PO Phase II
Sector 67 PO Phase I
Sector 78 PO Phase II
Sector 81 PO Phase II
Cool down
15
Revised target for 2009
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First lead ions in LHC
23.-25. October
Injection region screens
Mike Lamont
TI2/S23 first trajectory
TI2
S23
17
Trajectory difference before/after precycle
IP2
IP3
Reproducibility looks very good
18
Injection region aperture
Model
Measured
BrennanGoddard
19
Injection region trajectories through arc
IR3
IR2
20
First beam to point 7
In the aperture model
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Dispersion TI8/S78
Measured v. model
TI8
S78
Normalized
22
Kick response
IP2
IP3
Problem?
Beam
Green Measured Purple - model
23
Sunday Walter starts early
Collimator scan
H
Non-closure of LHCb dipole and compensators with
LHCb dipole at full field (rms 1 mm)
V
Beam
24
Aperture
25
Proton commissioning (as planned since 2005)
(A)
2009
Repair of Sector 34 Installation of protection systems Hardware commissioning
Machine checkout Beam commissioning
No beam
Beam
A
B
2010
43/156 bunch operation 50ns operation 25ns operation ? Shutdown
Beam
No beam
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Targets with beam 2009
Do this with safe beams 1012 at 450 GeV ? 2 1011
at 1.1 TeV, 3 1010 at 3.5TeV LIMIT 2 on 2 with
5 1010 per bunch at 1.1 TeV 2 on 2 with 1010 per
bunch at 3.5TeV
27
Christmas break

• Stop LHC with beam
• 17th December 2009, restart 7th January 2010
• Cryogenics
• 2 days to set-up 3 K for Christmas
• 3 days on return to re-establish 1.9 K
• Coverage over stop - details to be finalized
• All machines on standby except for
• Essential maintenance work on LHC will be
  performed during the stop
• Essential maintenance work on injectors will be
  performed during the stop