Partikeldagarna, Göteborg 21 September 2007
LHC: Status and PlansLyn Evans
L. Evans – EDMS document 867980 2
Schematic layout of the LHC
L. Evans – EDMS document 867980 3
Main parameters of LHC (p-p)
• Circumference 26.7 km• Beam energy at collision 7 TeV• Beam energy at injection 0.45 TeV• Dipole field at 7 TeV 8.33 T• Luminosity 1034 cm-2.s-1
• Beam current 0.56 A• Protons per bunch 1.1x1011
• Number of bunches 2808• Nominal bunch spacing 24.95 ns• Normalized emittance 3.75 m• Total crossing angle 300 rad• Energy loss per turn 6.7 keV• Critical synchrotron energy 44.1 eV• Radiated power per beam 3.8 kW• Stored energy per beam 350 MJ• Stored energy in magnets 11 GJ• Operating temperature 1.9 K
L. Evans – EDMS document 867980 4
Descent of the last magnet, 26 April 2007
30’000 km underground at 2 km/h!
L. Evans – EDMS document 867980 5
Cross-section of LHC cryodipole
L. Evans – EDMS document 867980 6
Dipole magnetic flux plot
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Critical current density of technical superconductors
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Bending strength of dipoles
10.07
10.09
10.11
10.13
10.15
0 100 200 300 400 500 600 700 800 900 1000 1100 1200
Magnet progressive number
Int t
rans
f fun
c (T
m/k
A)
-40
-20
0
20
40
Uni
ts
Firm 1
Firm 2
Firm 3
AT-MAS
Cold mass
upper limit for single magnet (3 sigma)
lower limit for single magnet (3 sigma)
L. Evans – EDMS document 867980 9
Field errors in dipole production: b3
-10
-5
0
5
10
0 100 200 300 400 500 600 700 800 900 1000 1100 1200
Magnet progressive number
b3 in
teg
ral (
units
)
Firm 1
Firm 2
Firm 3
Cold mass
upper limit for systematic
lower limit for systematic
AT-MAS & MTM
Cro
ss-s
ecti
on
2
Cross-section 3
L. Evans – EDMS document 867980 10
Field orientation in dipoles
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0 100 200 300 400 500 600 700 800 900 1000 1100 1200
Collared coil progressive number
Tw
ist
inte
gral
of
mai
n fie
ld a
ngle
Firm 1Firm 2Firm 3
AT-MAS
upper limit for single magnet
lower limit for single magnet
Cold mass all positions (mrad)
L. Evans – EDMS document 867980 11
Systematic field errors in dipoles
-5
-4
-3
-2
-1
0
1
2
3
4
5
0
Targets
Measured
Cold mass - systematic vs targets
a3 a4
b2 a
pert
ure
1
b2 a
pert
ure
2
b2 b
oth
aper
ture
s
b4 a
pert
ure
1
b4 a
pert
ure
2
b4 b
oth
aper
ture
s
a2 a5
AT-MAS-6
-4
-2
0
2
4
6
9
Targets
Measured
b3b5
b7
AT-MAS
L. Evans – EDMS document 867980 12
Random field errors in dipoles
0.0
0.5
1.0
1.5
2.0
1
Type R
Type L
Targets
AT-MAS
Cold mass - random (r.m.s) vs targets
L B BdL b2 b3 b4 b5 b7a2 a3 a4 a5
units/10 units
L. Evans – EDMS document 867980 13
Dipole-dipole interconnect
L. Evans – EDMS document 867980 14
Dipole-dipole interconnect: electrical splices
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DFBAO in Sector 7-8
L. Evans – EDMS document 867980 16
Magnet interconnections
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Specific heat of LHe and Cu
0,00001
0,0001
0,001
0,01
0,1
1
10
100
0 1 2 3 4 5Temperature [K]
Spe
cific
hea
t [J
/g.K
]
LHeCu
L. Evans – EDMS document 867980 18
Equivalent thermal conductivity of He II
0
500
1000
1500
2000
1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2
T [K]
Y(T
) ±
5%
T
K T,q q Y T
dT
dX
q
Y(T)
q in W / cm
T in K
X in cm
2.4
3.4
2
OFHC copper
Helium II
L. Evans – EDMS document 867980 19
Phase diagram of Helium
1
10
100
1000
10000
1 10
T [K]
P [k
Pa]
SOLID
HeII HeI
CRITICAL POINT
GAS
l line
Saturated He II
Pressurized He II
L. Evans – EDMS document 867980 20
Linear heat exchanger
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Sector 7-8 cooldown
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Courtesy F.Bordry
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Tracking between the three main circuits of sector 78
Courtesy F.Bordry
2ppm
L. Evans – EDMS document 867980 24
Arc plug-in module at warm temperature
L. Evans – EDMS document 867980 25
Arc plug-in module at working temperature
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Module with installation compression tooling
L. Evans – EDMS document 867980 27
RF bellows in the 1700 interconnections
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Transmitter prototype
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Transmitter prototype
L. Evans – EDMS document 867980 30
The electron cloud effect
L. Evans – EDMS document 867980 31
Simulated heat load as a function of SEY
L. Evans – EDMS document 867980 32
Energy stored in the accelerator beam, as a function of beam momentum. At less than 1% of nominal intensity LHC enters new territory.
Stored energy density as a function of beam momentum. Transverse energy density is a measure of damage potential and is proportional to luminosity.
Beam momentum & stored energy of colliders
L. Evans – EDMS document 867980 33
Transverse emittances from 3 different bunch intensities (72 bunches)
L. Evans – EDMS document 867980 34
Conclusions
The LHC design has integrated more than 30 years of accumulated
knowledge of the behaviour of beams in hadron storage rings. The various
correction systems will be adequate to stabilise the beams up to and beyond
design luminosity.
The one new effect is the electron cloud which may be the limiting factor in
pushing the luminosity well above the design value. This will depend on the
efficiency of scrubbing that can be achieved.
The rate of increase in luminosity will be governed by our ability to protect the
machine and detectors and of the detectors to cope with it.
L. Evans – EDMS document 867980 35
CERN accelerator complex
L. Evans – EDMS document 867980 36
Upgrade components
PSB
SPSSPS+
Linac4
LPSPL
PS
LHC / SLHC DLHC
Out
put e
nerg
y
160 MeV
1.4 GeV4 GeV
26 GeV50 GeV
450 GeV1 TeV
7 TeV~ 14 TeV
Linac250 MeV
LPSPL: Low PowerSuperconducting Proton Linac (4 GeV)
PS2: High Energy PS(~ 5 to 50 GeV – 0.3 Hz)
SPS+: Superconducting SPS(50 to1000 GeV)
SLHC: “Superluminosity” LHC(up to 1035 cm-2s-1)
DLHC: “Double energy” LHC(1 to ~14 TeV)
Proton flux / Beam power
PS2
PSB
SPSSPS+
Linac4
LPSPL
PS
LHC / SLHC DLHC
Out
put e
nerg
y
160 MeV
1.4 GeV4 GeV
26 GeV50 GeV
450 GeV1 TeV
7 TeV~ 14 TeV
Linac250 MeV
LPSPL: Low PowerSuperconducting Proton Linac (4 GeV)
PS2: High Energy PS(~ 5 to 50 GeV – 0.3 Hz)
SPS+: Superconducting SPS(50 to1000 GeV)
SLHC: “Superluminosity” LHC(up to 1035 cm-2s-1)
DLHC: “Double energy” LHC(1 to ~14 TeV)
Proton flux / Beam power
PS2
L. Evans – EDMS document 867980 37
Layout of the new injectors
SPS
PS2
SPL
Linac4
PS
L. Evans – EDMS document 867980 38
Upgrade of LHC insertions
Intermediate (2012-2013) upgrade of the two high-
luminosity insertions using existing NbTi cable from dipole
production. Seed money expected from Brussels but
construction funds to be found.
Possible further upgrade to IE35 (2016-2018) using
advanced superconductor. Many ideas but luminosity
lifetime will be a problem.