Partikeldagarna , Göteborg 21 September 2007

Partikeldagarna, Göteborg 21 September 2007

LHC: Status and PlansLyn Evans

L. Evans – EDMS document 867980 2

Schematic layout of the LHC


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


Descent of the last magnet, 26 April 2007

30’000 km underground at 2 km/h!


Cross-section of LHC cryodipole


Dipole magnetic flux plot


Critical current density of technical superconductors


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)


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


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)


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


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


Dipole-dipole interconnect


Dipole-dipole interconnect: electrical splices


DFBAO in Sector 7-8


Magnet interconnections


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


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


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


Linear heat exchanger


Sector 7-8 cooldown


Courtesy F.Bordry


Tracking between the three main circuits of sector 78

Courtesy F.Bordry

2ppm


Arc plug-in module at warm temperature


Arc plug-in module at working temperature


Module with installation compression tooling


RF bellows in the 1700 interconnections


Transmitter prototype


Transmitter prototype


The electron cloud effect


Simulated heat load as a function of SEY


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


Transverse emittances from 3 different bunch intensities (72 bunches)


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.


CERN accelerator complex


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


Layout of the new injectors

SPS

PS2

SPL

Linac4

PS


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.

Documents

Partikeldagarna , Göteborg 21 September 2007