Aceleradores

2

3

4

5

6

Radio-

Frequency

system

F = m·a = q·DV/d

v = a·t = t·q ·DV/ d /m

E = q·DV

d

7

8

9

10

11

12

13

14

15

16

La energía almacenada por los todos los imanes del LHC a 14 TeV es de 10.4 GJ (g ~ 7000)• 3.1 m/s más despacio que la luz, 11000 vueltas/s!!! Comparando con los aceleradores previos:

• Campo magnético: x 2 (~8T)• Energía del haz: x 7 (7+7= 14TeV)• Energía almacenada: x 200 (b = 0.999999 99 ·c )

10 GJ A380 @ 700 km/h

18

1976

1988

2000

19LEP LHC

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21

22

23

24

25

26

27

m = g m0……

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29

Ejemplo, visto en las

técnicas III en la práctica

de la cámara de Niebla:

Speed (units of c) Lorentz factor (g)

0.000 1.000

0.250 1.033

0.300 1.048

0.400 1.091

0.500 1.155

0.600 1.250

0.700 1.400

0.750 1.512

0.800 1.667

0.866 2.000

0.900 2.294

0.990 7.089

0.999 22.366

0.99995 100.000

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31

32

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33

Cathode Ray Tube (CRT) has the basic

ingredients of a scientific accelerator:

Particle source

Acceleration scheme

Focusing scheme

Beam steering

Beam observation

( )dp

F q E v Bdt

= = + ´

rr r rrParticle momentum p given by Lorentz Force:

Particle momentump =r

Electric fieldE =r

Magnetic fieldB =r

Particle chargeq =Particle velocityp =r

dp / dt =

34

LEP 1989-2000

0.21TeV

35

Tevatron

Tevatron 1983-2011

2TeV

7TeV → 14TeV

Longitud: 27 km

Profundidad: ~ 100 m

2010-2040?

36

LHC

37R. Assmann 37

3838

High Beam Energy with Super-Conducting

Magnets: Handle High Currents and Large Stored Energy

24.9.09 38

39

•Se usan electroimanes dipolares para acelerar los

protones y mantener su trayectoria. Cada uno tiene

15m de longitud y pesa 35 Tm.

•Existen 20 km de estos imanes superconductores y

para enfriarlos a 1.9 K se usan 96 Tm de He

superfluido

•Se requieren campos magnéticos de 8.3 T para

mantener la trayectoria de los protones, cada uno con

una corriente de 11,700 A. En una casa familiar

medio se usan menos de 70 A.

40

Ensamblado de Imanes en el CERN

41

LHC: Super-Conducting RF

Cavities

R. Assmann 41

time

RMS bunch length 11.2 cm 7.6 cmRMS energy spread 0.031% 0.011%

450 GeV 7 TeV2.5 ns

42

LHC: Colimadores

R. Assmann 42

43

Desafíos …

27 km 99.9999999%

la velocidad de la luz

40 000 000 colisiones por

segundo

44

44

1232 main

dipoles +

3700

multipole

corrector

magnets

392 main

quadrupoles +

2500 corrector

magnets

Regular arc:

Magnets

45

El lugar más frío del universo

He líquidoT = -271,3 C

46

46

Regular arc:

Cryogenics

Supply and recovery of

helium with 26 km long

cryogenic distribution

line

Static bath of superfluid

helium at 1.9 K in cooling

loops of 110 m length

Connection via service

module and jumper

R. Schmidt

47

El espacio más vacío del Sistema Solar

10-13 atmósferas, ¡diez veces menos que la presión de la Luna!

48

48

Insulation vacuum for

the cryogenic

distribution line

Regular arc:

Vacuum

Insulation vacuum for the

magnet cryostats

Beam vacuum for

Beam 1 + Beam 2

49

El lugar más caliente del

universo

160 000 000 000 000 000 C

50

50

Examples of damage from beams

Lead block

accidentally put into

a p beam

Entry and exit holes of an electron beam

impacting on a spoiler

51

27 km de carrera

hasta…

52

Los detectores más grandes y sofisticados jamás construidos

5353

Crossing angle ≳ ± 140 μrad

Quadrupoles start at L* = 23 m from IP

Two beam pipes, horizontally separated by 19.4 cm

54

5555

To get to 7 TeV: Synchrotron – circular

accelerator and many passages in RF cavitiesLINAC (planned for several hundred GeV - but not above 1 TeV, e.g ILC)

LHC circular machine with energy gain per turn ~0.5 MeV

acceleration from 450 GeV to 7 TeV takes about 20 minutes

....requires deflecting magnets (dipoles)

56

The Charged Particle Beam• The accelerator generates, accelerates, transports and

delivers beams to the user (e.g. HEP exp).

• Beam are transported in ultra-high vacuum.

• A beam can consist of individual bunches.

• Each “bunch” is an ensemble of charged particles that are

grouped together in space and carry the same (very similar)

energy (±0.1%).

• Radio-frequency fields are used to accelerate particles

coherently and to group them together longitudinally.

• Magnetic fields are used to guide the beam particles on well

defined paths and to focus them into a small transverse area.

57

LHC: Longer Term Future

• 2010 – 2011: Physics Run1@3.5 TeV (7 TeV Ecm)

• 2012: Physics Run1@4 TeV (8 TeV Ecm)

• 2013 – 2014: Shutdown: Repair of interconnects

• 2015 – 2018: Physics Run2@6.5 TeV (13 TeV Ecm)

• 2019 – 2020: Shutdown. Upgrades and repairs

• 2021 – 2023: Physics Run3@7 TeV (14 TeV Ecm)

• Long term:

– HL-LHC upgrade >2024? 5-10 times higher luminosity

same beam energy

– HE-LHC upgrade higher beam energy

magnets do not exist yet…57

58

The choice of particle type•Hadron colliders

(p-pbar or pp or ions)

“Discovery” machines

Tevatron 1983-2011

p-p: 2 x 1TeV

LHC 2021

p-p: 2 x 7 TeV

VLHC study (?)

p-p: 2 × 20 TeV

2 ×100 TeV

•Lepton colliders

(e-e+)

LEP ECM~210GeV

“Precision” studies

Linear collider study

e+e-: 0.5-1.5 TeV

(eg, gg, e-e- options)

mm collider study

2 × 0.15/4.0 TeV

Plasma accelerators

59

60

61

62

International Linear ColliderILC Facts

• Cavity temperature: 2 K

• Detectors: 2, based on complementary technologies

• Site:To be determined

• ILC Community:Nearly 300 laboratories and universities around the world are involved in the ILC: more than 700 people are working on the accelerator design, and another 900 people on detector development. The accelerator design work is coordinated by the Global Design Effort, and the physics and detector work by the World Wide Study.

• Collisions:Between electrons and their antiparticles, positrons, in bunches of 5 nanometres (5 billionths of a metre) in height each containing 20 billion particles and colliding 14,000 times per second

• Energy:Up to 500 GeV

with an option to upgrade to 1 TeV

• Acceleration Technology:16,000 superconducting accelerating cavities made of pure niobium

• Length:Approximately 31 kilometres, plus two damping rings each with a circumference of 6.7 kilometres

• Accelerating Gradient: 31.5 megavolts per metre

http://www.linearcollider.org/

Very Large Hadron Collider

63http://vlhc.org/

64

Luminosidad

Triplet

aperture

and

collimation

setup

accuracy

Loss limits:

collimation,

(UFO’s), …

Beam-

beam,

brightness

& robust-

ness limits

http://lpc.web.cern.ch/lpc/lumi.html

The design luminosity of the LHC is

1034 cm−2s−1=10nb-1s-1 providing a

bunch collision rate of 40 MHz

65

Understanding LHC Page 1

http://op-webtools.web.cern.ch/op-webtools/vistar/vistars.php?usr=LHC1

66

Luminosidad

• ~1018 colisiones = ~1000000 de

Billones de colisiones

• Un barn se define como

10−24 cm2 y es aproximadamente

el área de sección eficaz de un

núcleo de Uranio

• 1fb = 10-39cm2 →1 fb-1 = 1039 cm-2

• spp@8TeV = 69.4b = 69.4·1015 fb