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Giulia Papotti(BE-OP-LHC)
for the LHC team
127th LHCC MeetingCERN, 21 September 2016
thanks in particular to M. Lamont and J. Wenninger
additionally, with material from:
S. Danzeca, M. Hostettler, G. Iadarola, J. Jowett, C. Schwick, M. Solfaroli, J. Wenninger
outline
• 2016 performance
• some details on selected subjects• electron cloud, Unidentified Falling Objects, Radiation to
Electronics
• latest news, schedule and outlook
2016.09.21 [email protected]
peak luminosity
2016.09.21 [email protected]
2016 2015 Design Report
energy [TeV] 6.5 6.5 7
bunch spacing [ns] 25 25 25
b* [cm] 40 80 55
eN[mm mrad] at start of fill 2 3.5 3.75
Nb, bunch population [1011 p/bunch] 1.12 1.15 1.15
k, max. number of bunches 2220 2240 2808
max. stored energy [MJ] 260 270 360
peak luminosity [1034 cm-2s-1] in IP1/5 ~1.25 ~0.5 1
pile-up 41 18 20
2016 performance so far
• cf target for 2016: 25 fb-1
• max. luminosity delivered in
7 days: 3.3 fb-1 (ATLAS)- Mon 29 Aug – Sun 4 Sep
2016.09.21 [email protected]
Peak
Luminosity[cm-2s-1]
Integrated
Luminosity[fb-1]
ATLAS 1.21 1034 29.3
CMS 1.33 1034 30.5
put in perspective
2016.09.21 [email protected]
physics efficiency
• improved operational efficiency - combine ramp and squeeze
- shorten precycle
- minimum turn around <3 h
• amazing system availability!- cf ~33-35% in stable beams of
the previous years
2016.09.21 [email protected]
65% 20%
15%
FAULTS
STABLE
BEAMS
OPERATION
mid-year availability,
physics production only
(no commissioning, MD, …)
• good luminosity lifetime- optimize fill length and dump time
beam parameters
• number of bunches per injection limited to 96 by SPS dump- max 2220 bunches/ring
• intensity per bunch limited to 1.1e11 ppb- outgassing from ceramic connection in
LHC injection kicker
• smaller emittance and high brightness from BCMS beams- Batch Compression, Merging and Splitting
- 2 um into collision, cf 3.75 um nominal
2016.09.21 [email protected]
BMCSstandard
limitations
• SPS beam dump: replace during EYETS
• injection kicker: add pumping during EYETS
• potential inter-turn short in sector 12- being monitored
- lowered Beam Loss Monitor thresholds to play it safe
- to be replaced during the EYETS
• electron-cloud
• Unidentified Falling Objects
• Radiation to Electronics (R2E)
2016.09.21 [email protected]
electron cloud• SEY>threshold: avalanche effect (multipacting)
- effect depends on bunch spacing and population
- SEY decreases with accumulated dose: “scrubbing”
• e-cloud effects observed in LHC with bunch trains- vacuum pressure rise, heat load on cryogenic systems
- beam size growth, single- and multi-bunch instabilities
• anticipated & confirmed to be a challenge with 25 ns- 2015: lived at the heat-load limit
• 2016: still significant heat-load within cryogenic limits- scrub with physics asap (almost no dedicated scrubbing at the flat bottom)
- dynamics well handled by cryogenics feed-forward, no impact on operations
2016.09.21 [email protected]
Secondary
Emission
Yield
little improvement
over the year
Unidentified Falling Objects (UFOs)
• fast loss events (ms timescale) due to dust particles falling into the beam- feared for availability at high energy operation: less margin for magnets, more losses per event
• 2016 so far: 13 dumps + 3 beam-induced quenches- loss monitor thresholds increased to allow few quenches per year
• most beam dumps would not have quenched
• conditioning with beam time confirmed- very high rates observed at start 2015, now settled at ~2 arc UFOs/hour in stable beams
- deconditioning did not take place after year end stop
2016.09.21 [email protected]
2015 2016
Radiation to Electronics (R2E)
• failure rates proportional to radiation levels- IP: rad level mainly from integrated luminosity
- arc: rad level mainly from beam-gas interaction, thus integrated intensity
• 2016: 3 radiation-related dumps up to 20 fb-1 (expected ~1 dump/fb-1)- arc radiation levels per unit luminosity are lower than in 2015
• can be due to the lower vacuum pressure in the arc, or to the higher luminosity per proton (smaller beta*), analysis ongoing
• very clean machine, luminosity losses are burn-off dominated, less e-cloud
2016.09.21 [email protected]
0
0
1
10
DCUM
16L5 16R5IR5
loss ratio
2016 vs 2015
per fb-1
(over 20 fb-1)
IP: ratio is 1
arc: ratio is 0.3
incoming: 2016
• ongoing this week:- 2.5 km beta* run
- crossing angle reduction for low beta* proton physics
• next:- 9 days of machine developments
- dense ion run: p-Pb at 5 TeV, p-Pb and Pb-p at 8 TeV,
- 2 weeks of dipole training towards 7 TeV equivalent• before Extended Year End Technical Stop (EYETS)
2016.09.21 [email protected]
ML
V2.0
Jan Feb Mar
Wk 1 2 3 4 5 6 7 8 9 10 11 12 13
Mo 4 11 18 25 1 8 15 22 29 7 14 21 28
Tu
We
Th
Fr
Sa
Su
Apr May June
Wk 14 15 16 17 18 19 20 21 22 23 24 25 26
Mo 4 11 18 25 2 9 16 23 30 6 13 20 27
Tu
We
Th
Fr
Sa
Su
July Aug Sep
Wk 27 28 29 30 31 32 33 34 35 36 37 38 39
Mo 4 11 18 25 1 8 15 22 29 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Oct Nov Dec
Wk 40 41 42 43 44 45 46 47 48 49 50 51 52
Mo 3 10 17 24 31 7 14 21 28 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Technical Stop Machine development
Recommissoning with beam Special physics runs
Scrubbing
September 1, 2016
LHC Schedule 2016Approved by the Research Board, December 2015
Year end technical stop
Xmas
MD 2
TS1
End of LHC run[06:00]
Extended year end technical stop
MD 4
MD 5
Ion run(p-Pb)
TS2
Ionssetup
Recommissioningwith beam
TS3
1st May
Ascension
Easter Mon
Whit
Jeune G
New Year
MD 1
Powering tests
Lab closed
May Day comp
be
ta
* =
2.5
km
da
ta
ta
kin
g
VdM
DSO test
beta* 2.5 kmdev.
beta* 2.5 kmdev.
Ma
ch
ine
ch
ecko
ut
G. Friday
Injector TS(8 hours)
Scrubbing
Pb MD
VdM
MD 3
beta* 2.5 kmdev.
ML
V2.0
Jan Feb Mar
Wk 1 2 3 4 5 6 7 8 9 10 11 12 13
Mo 4 11 18 25 1 8 15 22 29 7 14 21 28
Tu
We
Th
Fr
Sa
Su
Apr May June
Wk 14 15 16 17 18 19 20 21 22 23 24 25 26
Mo 4 11 18 25 2 9 16 23 30 6 13 20 27
Tu
We
Th
Fr
Sa
Su
July Aug Sep
Wk 27 28 29 30 31 32 33 34 35 36 37 38 39
Mo 4 11 18 25 1 8 15 22 29 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Oct Nov Dec
Wk 40 41 42 43 44 45 46 47 48 49 50 51 52
Mo 3 10 17 24 31 7 14 21 28 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Technical Stop Machine development
Recommissoning with beam Special physics runs
Scrubbing
September 1, 2016
LHC Schedule 2016Approved by the Research Board, December 2015
Year end technical stop
Xmas
MD 2
TS1
End of LHC run[06:00]
Extended year end technical stop
MD 4
MD 5
Ion run(p-Pb)
TS2
Ionssetup
Recommissioningwith beam
TS3
1st May
Ascension
Easter Mon
Whit
Jeune G
New Year
MD 1
Powering tests
Lab closed
May Day comp
be
ta
* =
2.5
km
da
ta
ta
kin
g
VdM
DSO test
beta* 2.5 kmdev.
beta* 2.5 kmdev.
Ma
ch
ine
ch
ecko
ut
G. Friday
Injector TS(8 hours)
Scrubbing
Pb MD
VdM
MD 3
beta* 2.5 kmdev.
ML
V2.0
Jan Feb Mar
Wk 1 2 3 4 5 6 7 8 9 10 11 12 13
Mo 4 11 18 25 1 8 15 22 29 7 14 21 28
Tu
We
Th
Fr
Sa
Su
Apr May June
Wk 14 15 16 17 18 19 20 21 22 23 24 25 26
Mo 4 11 18 25 2 9 16 23 30 6 13 20 27
Tu
We
Th
Fr
Sa
Su
July Aug Sep
Wk 27 28 29 30 31 32 33 34 35 36 37 38 39
Mo 4 11 18 25 1 8 15 22 29 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Oct Nov Dec
Wk 40 41 42 43 44 45 46 47 48 49 50 51 52
Mo 3 10 17 24 31 7 14 21 28 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Technical Stop Machine development
Recommissoning with beam Special physics runs
Scrubbing
September 1, 2016
LHC Schedule 2016Approved by the Research Board, December 2015
Year end technical stop
Xmas
MD 2
TS1
End of LHC run[06:00]
Extended year end technical stop
MD 4
MD 5
Ion run(p-Pb)
TS2
Ionssetup
Recommissioningwith beam
TS3
1st May
Ascension
Easter Mon
Whit
Jeune G
New Year
MD 1
Powering tests
Lab closed
May Day comp
be
ta
* =
2.5
km
da
ta
ta
kin
g
VdM
DSO test
beta* 2.5 kmdev.
beta* 2.5 kmdev.
Ma
ch
ine
ch
ecko
ut
G. Friday
Injector TS(8 hours)
Scrubbing
Pb MD
VdM
MD 3
beta* 2.5 kmdev.
ML
V2.0
Jan Feb Mar
Wk 1 2 3 4 5 6 7 8 9 10 11 12 13
Mo 4 11 18 25 1 8 15 22 29 7 14 21 28
Tu
We
Th
Fr
Sa
Su
Apr May June
Wk 14 15 16 17 18 19 20 21 22 23 24 25 26
Mo 4 11 18 25 2 9 16 23 30 6 13 20 27
Tu
We
Th
Fr
Sa
Su
July Aug Sep
Wk 27 28 29 30 31 32 33 34 35 36 37 38 39
Mo 4 11 18 25 1 8 15 22 29 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Oct Nov Dec
Wk 40 41 42 43 44 45 46 47 48 49 50 51 52
Mo 3 10 17 24 31 7 14 21 28 5 12 19 26
Tu
We
Th
Fr
Sa
Su
Technical Stop Machine development
Recommissoning with beam Special physics runs
Scrubbing
September 1, 2016
LHC Schedule 2016Approved by the Research Board, December 2015
Year end technical stop
Xmas
MD 2
TS1
End of LHC run[06:00]
Extended year end technical stop
MD 4
MD 5
Ion run(p-Pb)
TS2
Ionssetup
Recommissioningwith beam
TS3
1st May
Ascension
Easter Mon
Whit
Jeune G
New Year
MD 1
Powering tests
Lab closed
May Day comp
be
ta
* =
2.5
km
da
ta
ta
kin
g
VdM
DSO test
beta* 2.5 kmdev.
beta* 2.5 kmdev.
Ma
ch
ine
ch
ecko
ut
G. Friday
Injector TS(8 hours)
Scrubbing
Pb MD
VdM
MD 3
beta* 2.5 kmdev.
year end technical stop
powering tests
machine checkout
re-commission
with beam
full-on
physics production
includes
machine developments
ion run
powering tests
year end technical stop
today
crossing angle reduction
• crossing angle required because of bunch trains- otherwise parasitic collisions not in the center of the detector
- negative impact on luminosity… keep it as small as possible
• constraint: minimum beam separation- big beam emittance or small beta* require bigger crossing angle
• BCMS beams are smaller than standard- machine setup for standard, now reduce crossing angle
- plan it well: validation overhead not to dominate!
2016.09.21 [email protected]
f [mrad] 370 280
F 0.59 0.70
Lpk [1034cm-2s-1] 1.27 1.5
Run 2 schedule
• Extended Year End Technical Stop (20 weeks)- driven by CMS pixel upgrade
- push 2 sectors towards 7 TeV, to gain knowledge on how long it takes to reach higher energy
• ~40-45 fb-1/year in 2017 and 2018 (goals fixed at Chamonix 2017) - max peak luminosity ~1.7e34 cm-2s-1, limited by inner triplets
2016.09.21 [email protected]
today
projections until LS2
• BCMS or not?- BCMS: low emittance, thus low crossing angle: higher luminosity/bunch pair
• TDI limits on number of bunches/SPS transfer: less bunches/ring
• less electron-cloud thanks to the shorter trains
- standard beams: +30% bunches, but higher emittance: likely less luminosity• less pile-up
- choice requires input from experiments
• if pile-up is an issue, level down
• need to start the year with the correct parameter set!- commissioning and validation are non-negligible overhead
• availability is the key to good integrated luminosity!- max peak luminosity is limited
- 2016, 2017, 2018: similar run length
2016.09.21 [email protected]
machine developments• reserve ~10% of beam time per year
• invest it in short & long term performance improvements
• examples in 2016:- luminosity performance: beta* reach, reduced crossing angle, luminosity levelling options
- HL-LHC optics (ATS) for possible deployment in Run 2
- collective effects & instability limits
- hardware performance (collimators, RF, ...)
- many many others!
2016.09.21 [email protected]
160 140 120 100 185 100 185
10%
CMS
ALICE
½ xing angle in mrad
ex 1: leveling by crossing angle
ex 2: leveling by separation
time [h]
lum
ino
sity [H
z/u
b]
conclusions
• excellent peak performance- above design luminosity (squeeze further, bright beams from injectors)
- still some margin for improvement in Run 2
• good delivery of integrated luminosity- stunning availability
- good luminosity lifetime
- electron cloud conditioning very slowly
- fortunately UFOs have conditioned down
• the LHC has moved from commissioning to exploitation- enjoying the benefits of the decades long international design,
construction, installation effort: the foundations are good
- huge amount of experience & understanding gained and fed-forward
• astounding results and progress represent a phenomenal ongoing effort by all the teams involved
2016.09.21 [email protected]
the Large Hadron Collider
Lake of Geneva
CMS
Pt4: RF & BI
SPS
2016.09.21 [email protected]
ATLASLHCb
ALICE
Pt7: collimators
Pt3: collimators
Pt6: dump
Pt8: inj b2
Pt2: inj b1
LHC operation history
2016.09.21 [email protected]
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
firststart-up
Long Shutdown 1
Long Shutdown 2
first experience(3.5 TeV)
probing the limits
production(4 TeV, 50 ns beams)
first experience(6.5 TeV, 25 ns beams)
production
production
production
2015 goalestablish p+p+ collision
at 13 TeV CoMwith 25 ns and low b*:
(prepare production in 2016)
luminosity lifetime
• emittance- small horizontal growth, vertical shrinkage
(MOPMR025)• enjoy benefits of synchrotron radiation,
small IBS (TUPMW002)
• some additional blow up
- longitudinal shrinkage• get to the limit of stability in long fills
• good transmission- ~2% losses from start of acceleration to
physics
• in physics, mainly losses from burn-off
• healthy luminosity lifetime- 30-60 hours
- long fills are preferred (>20 hours)
2016.09.21 [email protected]
courtesy of M. Hostettler
courtesy of J. Muller
hardware performance at 6.5 TeV
• dipole quenches- slow training of main dipoles to 6.5 TeV
• had 175 quenches, while expected ~100
- only 5 training quenches during beam operation
- possible test of 7 TeV before Long Shutdown 2
• magnets behave well at 6.5 TeV
• excellent magnetic reproducibility- allow control and feedforward of tune and
chroma
2016.09.21 [email protected]
• cryogenic system handling electron-cloud driven heat-load transients- new algorithm, first 2016 test look excellent
beta*11m 0.8m
courtesy of
A. Gorzawski
machine studies: beta* levelling
• 10% of time with beam invested in machine studies
• pick one highlight among many- TUPMW013: beta* leveling, and collide + squeeze fully demonstrated
• see the beta* go down and lumi increase smoothly, over 12 minutes
2016.09.21 [email protected]
25Matteo Solfaroli, Weihai – 14th Aug 2016
A few problems