1. Luminosity and time estimates
Mike Lamont
Thanks for discussion: R. Assmann, R. Bailey, M. Ferro-Luzzi, S. Fartoukh, O. Bruning

2. Disclaimer The future is a strange place
Aim of the exercise is to establish some realistic numbers given accepted constraints
All numbers to be treated with a modicum of circumspection
Optimistic numbers can be treated as upper limits
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Luminosity estimates

3. Some formulae Halving time to luminosity – 2 IPs
Assume radiation damping compensates diffusion
And then optimize fill length
Following Ruggiero
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Luminosity estimates

4. Luminosity estimates Calculate peak luminosity given the usual inputs
Bunch current, number of bunches, emittance, beta*, crossing angle
Calculate luminosity lifetime given
Luminosity, cross-section
Beam-gas lifetime
IBS growth rates
Optimize fill length given an assumed turnaround time
Given fill length & luminosity lifetime – calculate integrated luminosity per fill
Multiply up
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Luminosity estimates

5. ~ 3 hour minimum. Assume 4 hours here – optimism bias
Turn around time
Physics to physics
Phase
Time [mins]
Ramp down and pre-cycle 60
Pre-injection preparation and checks 15
Checks with set-up beam (tunes, orbit etc.)
Nominal injection sequence 20
Ramp preparation 5
Ramp 25
Squeeze 30
Adjust 10
TOTAL
180
~ 3 hour minimum. Assume 4 hours here – optimism bias
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Luminosity estimates

6. Note: ramp down – precyclecombo
Perform ramp down of main bends, quads, IPQs, triplets etc.
Up to 40 minutes from 3.5 TeV values
At the same time precycle all other circuits
Sextupoles, correctors, compensators, warm magnets etc
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Luminosity estimates

7. Less than one hour turn around (after 8 years’ optimization)
LEP
No-one ever thought it could be as smooth as:
Less than one hour turn around (after 8 years’ optimization)
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Luminosity estimates

8. Of course it wasn’t always as good as that
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Luminosity estimates

9. Operation month/year After a year or so… 30 days per month
3 day technical stop & recovery
[~2 days machine development]
Absorbed into unavailability for this exercise
60% machine availability
During which time we are dedicated to trying to do physics
4 weeks of ions (plus one week setup)
Other requests e.g. Totem
Shutdown
Assume around 7 months proton physics per year
approx. 200 days, optimization possible with a 2 year cycle
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Luminosity estimates

10. The Hubner factor Standard method
Take schedule physics time (minus MD, scheduled stops etc.)
Take peak luminosity time number of seconds
Multiply by Hubner factor
Usually taken to be around 0.2
Takes into account luminosity lifetime, turnaround, unplanned interventions etc
Here I have explicitly calculated luminosity lifetime, optimal fill length etc.
End up with a HF of around 0.3
Long luminosity lifetime, long fills, 4 hour turn around
The LHC has to be good, rashly make the assumption that we can make it so.
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Luminosity estimates

11. Out with the crystal ball
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Luminosity estimates

12. Jorg’s approved steps to 2 MJ
Simple HF
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Luminosity estimates

13. Or what you can do with 2.9 MJ
TT40 Damage during 2004 High Intensity SPS Extraction / Goddard, B ; Kain, V ; Mertens, V ; Uythoven, J ; Wenninger, J
Or what you can do with 2.9 MJ
During high intensity extraction on 25/10/04 an incident occurred in which the vacuum chamber of the TT40 magnet QTRF4002 was badly damaged.
The beam was a 450 GeV full LHC injection batch of p+ in 288 bunches, and was extracted from SPS LSS4 with the wrong trajectory
4.4 e12 at 3.5 TeV
88 bunches at 5 e10
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Luminosity estimates

14. Massimo Giovannozzi et al
2010++
Massimo Giovannozzi et al
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Luminosity estimates

15. Int Lumi per month [pb-1]
2011
3.5 TeV: run flat out at ~100 pb-1 per month Nb
ppb
Total Intensity MJ
beta*
Peak Lumi
Int Lumi per month [pb-1]
50 ns
432
7 e10
3 e13 17
2.5
7.4 e31
~63 (34)
Pushing intensity limit
796
5.1 e13 31
1.4 e32
~116 (63)
16% nominal
Should be able to deliver around 1 fb-1
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Luminosity estimates

16. Round beam approximation
Beam beam tune shift
Round beam approximation
7 e10 gives around 0.009
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Luminosity estimates

17. Constraints to 2015
Energy
Splice consolidation
Should open the way to 6.5/7 TeV
~2 years at 6.5 TeV before hitting 7 TeV
Beam intensity limits from collimation phase 1
40% maximum – less with imperfections
X: modification of DS
X + 1: DS collimators buys nominal intensity
2014/2015: Full phase 2 buys nominal and ultimate intensity
If X > 0 then assume everything done after 2014 run
Until then 40% limit holds – which is not a major disaster
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Luminosity estimates

18. NB: limit, not prediction
Collimation phase 2
NB: limit, not prediction
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Luminosity estimates

19. 2015 - 2020? Arrive at end 2014 (with a bit of luck) On the schedule:
7 TeV
Around 20% nominal performance
fb-1 in the bag
On the schedule:
LINAC4 (lose 6 months of proton physics)
DS collimators in – good for nominal
Collimation phase 2 – good for ultimate
Phase 1 upgrade (1 year shutdown plus re-commissioning)
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Luminosity estimates

20. 2015 - 2020? Statistical error halving time Accumulate X fb-1 per year?
Statistical error halving time
Accumulate X fb-1 per year
A naïve 3 more years at the same rate to halve the error
Flat lining soon becomes uninteresting
However, we’re hardly flat-lining at this stage
Clear that having yet to achieve nominal performance, another major shutdown would not be optimal at this stage
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Luminosity estimates

21. Plan A 2012++ – splice consolidation and DS collimation prep.
2013 – 6.5 TeV – ~25% nominal
2014 – 6.5 TeV – ~40% nominal
2015(?) – LINAC4 (6 months), collimation phase 2:
No phase 1 upgrade
Ions, 2 months recommissioning, 4 month protons
Presumably contingent on delivered integrated luminosity
2016: 7 TeV – nominal performance
2017 – 2020
A) Push to nominal and then flat-line (more-or-less)
B) Push towards ultimate
2020 – 2022 – possible upgrade
Presumably contingent on delivered integrated luminosity etc.
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Luminosity estimates

22. Plan A
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Luminosity estimates

23. To 2014 2012: splice consolidation (and DS collimator prep (?))
2013: 6.5 TeV ~25% nominal intensity
2014: 6.5 TeV ~40% nominal intensity
Year
Months
energy
beta ib nb
Peak Lumi
Lumi per month
Int Lumi
Int Lumi Cul
2010 8
3.5
2.5
7 e10
796
1.4 e32 -
0.1
2011 9
0.9
1.0
2012
2013 6
6.5 1
1 e11
720
1.2 e33
5.4 7
2014
1404
2.3 e33
1.8 13 20
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Luminosity estimates

24. At least in the same ball park
Independent estimate
Courtesy of a rather pessimistic but perhaps more realistic Massi Ferro-Luzzi
Year
Months
energy
beta ib nb
Peak Lumi
Lumi per month
Int Lumi
Int Lumi Cul
2010 6
3.5
2.5
7 e10
720
1.0 e32 -
0.1
2011 9
9 e10
2.0 e32 1
1.1
2012
2013
6.5
9 e32
0.45
2.7
3.8
2014
1404
1.7 e33
0.6
5.3
9.1
At least in the same ball park
Hubner Factor ~ 0.2
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Luminosity estimates

25. 2015 – to nominal
2015: Take a 6 month hit for LINAC4 & collimators phase 2, say,
Optimist
Year
Months
energy
beta ib nb
Peak Lumi
Lumi per month
Int Lumi
Int Lumi Cul
2015 4 7 1
11 e10
2808
6 e33
4.6 18 43
2016
0.55
1 e34
7.4 52 96
Might hope to hit nominal in 2016
Massi
2015 4 7 1
9 e10
2808
3.6 e33 2 8 17
2016 9
0.55
6.2 e33
3.2 29 46
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Luminosity estimates

26. Beyond 2016
Assumptions
PS at increased injection energy plus LINAC4 are good for ultimate (after a suitable commissioning period)
~1.7 x 1011 can be swallowed by the SPS
Give or take a long shutdown
LHC can swallow ultimate intensity
“Ultimate intensity is challenging for the LHC. Many systems at technological limits with little or no margin.”
(R. Assmann – Cham 2010)
Stay at or around nominal
Able to push towards ultimate
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Luminosity estimates

27.
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Luminosity estimates

28. Conclusions Luminosity estimates for the next ten years presented
Biased towards the optimistic
Nominal performance by 2016
21st century Hubner factors
Big errors bars and numbers should be treated with care particularly after 2016
Important to gain some operational experience!!!
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Luminosity estimates