Transcript Slide 1

LHC: Status and Plans
Partikeldagarna, Göteborg 21 September 2007
Lyn Evans
Schematic layout of the LHC
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Main parameters of LHC (p-p)
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Circumference
Beam energy at collision
Beam energy at injection
Dipole field at 7 TeV
Luminosity
Beam current
Protons per bunch
Number of bunches
Nominal bunch spacing
Normalized emittance
Total crossing angle
Energy loss per turn
Critical synchrotron energy
Radiated power per beam
Stored energy per beam
Stored energy in magnets
Operating temperature
26.7
7
0.45
8.33
1034
0.56
1.1x1011
2808
24.95
3.75
300
6.7
44.1
3.8
350
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1.9
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km
TeV
TeV
T
cm-2.s-1
A
ns
mm
mrad
keV
eV
kW
MJ
GJ
K
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Descent of the last magnet, 26 April 2007
30’000 km underground at 2 km/h!
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Cross-section of LHC cryodipole
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Dipole magnetic flux plot
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Critical current density of technical superconductors
3000
NbTi @ 4.5 K
NbTi @ 1.8 K
Nb3Sn @ 4.5 K
LHC Spec Cable 1
LHC Spec Cable 2
2500
Jc [A/mm2]
2000
1500
1000
500
0
6
7
8
9
10
11
12
B [T]
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Bending strength of dipoles
Cold mass
Firm 1
Firm 2
Firm 3
40
upper limit for single magnet (3 sigma)
10.13
20
10.11
0
10.09
-20
Units
Int transf func (Tm/kA)
10.15
lower limit for single magnet (3 sigma)
-40
10.07
0
100
200
300
400
500
600
700
800
900 1000 1100 1200
Magnet progressive number
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AT-MAS
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Field errors in dipole production: b3
5
upper limit for systematic
0
lower limit for systematic
Cross-section 2
b3 integral (units)
Cold mass
Firm 1
Firm 2
Firm 3
10
-5
Cross-section 3
-10
0
100
200
300
400
500
600
700
800
900
Magnet progressive number
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1100
1200
AT-MAS & MTM
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Field orientation in dipoles
Twist integral of main field angle
0.3
Firm 1
Firm 2
Firm 3
0.2
Cold mass all positions (mrad)
upper limit for single magnet
0.1
0.0
-0.1
-0.2
lower limit for single magnet
-0.3
0
100 200 300 400 500 600 700 800 900 1000 1100 1200
Collared coil progressive number
AT-MAS
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Systematic field errors in dipoles
2
1
9
b3
b5
b7
0
0
-1
-2
-2
-3
-4
a2 a3
a4 a5
-4
-6
AT-MAS
-5
b2 aperture 1
0
b4 both apertures
3
2
Measured
b4 aperture 2
4
4
b4 aperture 1
Measured
Targets
Cold mass systematic vs targets
5
b2 both apertures
Targets
b2 aperture 2
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AT-MAS
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Random field errors in dipoles
Cold mass - random (r.m.s) vs targets
2.0
units/10
units
1.5
Type R
Type L
Targets
1.0
0.5
0.0
1
L
B
BdL
b2
a2
b3
a3
b4
a4
b5
a5
b7
AT-MAS
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Dipole-dipole interconnect
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Dipole-dipole interconnect: electrical splices
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DFBAO in Sector 7-8
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Magnet interconnections
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Specific heat of LHe and Cu
100
Specific heat [J/g.K]
10
1
0,1
LHe
Cu
0,01
0,001
0,0001
0,00001
0
1
2
3
Temperature [K]
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5
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Equivalent thermal conductivity of He II
2000
KT,q   q 2.4  YT
dT q
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dX Y(T)
1500
Y(T) ± 5%
Helium II
3.4
q in W / cm2
1000
T in K
X in cm
500
T
OFHC copper
0
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
T [K]
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Phase diagram of Helium
10000
SOLID
P [kPa]
1000
HeII
100
l line
CRITICAL POINT
HeI
Pressurized He II
GAS
10
Saturated He II
1
1
10
T [K]
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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
Current [A]
7000
Quadrupole Circuits (RQF, RQD)
6000
5000
2ppm
4000
3000
2000
Dipole Circuit (RB)
1000
0
19:00
19:30
20:00
20:30
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21:30
Courtesy F.Bordry
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Arc plug-in module at warm temperature
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Arc plug-in module at working temperature
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Module with installation compression tooling
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RF bellows in the 1700 interconnections
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Transmitter prototype
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Transmitter prototype
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The electron cloud effect
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Simulated heat load as a function of SEY
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Beam momentum & stored energy of colliders
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.
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Transverse emittances from 3 different bunch intensities (72 bunches)
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Conclusions
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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.
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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.
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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.
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CERN accelerator complex
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Upgrade components
Proton flux / Beam power
50 MeV
160 MeV
Output energy
1.4 GeV
4 GeV
26 GeV
50 GeV
450 GeV
1 TeV
7 TeV
~ 14 TeV
Linac2
Linac4
PSB
LPSPL
PS
PS2
SPS
LHC /
SLHC
SPS+
LPSPL: Low Power
Superconducting 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)
DLHC
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Layout of the new injectors
SPS
PS2
SPL
PS
Linac4
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Upgrade of LHC insertions
 Intermediate (2012-2013) upgrade of the two highluminosity 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.
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