Future accelerators and technologies:

high-energy circular colliders,

+ novel accelerating technologies

1

Philip Burrows

John Adams Institute, Oxford University

2

c. 100 GeV

per beam

LEP

Synchrotron radiation

3

Discovered Elder et al

1947 (General Electric)

Synchrotron radiation

4

Power lost due to synchrotron radiation

P ~ E ** 4 / r**2

E = beam energy

r = radius of trajectory

Synchrotron radiation

5

Power lost due to synchrotron radiation

P ~ E ** 4 / r**2

E = beam energy

r = radius of trajectory

For LEP each electron lost ~ 3 GeV per turn (3%!)

P = 10**-6 Watts/electron 18 MW total

Must be compensated by accelerating cavities

6

Super Large Electron Positron collider?

500 GeV

beams?

(5 x LEP)

Synchrotron radiation

7

Suppose we increase LEP beam energy (100 GeV) by factor 5: E 500 GeV, in the same tunnel

P ~ E ** 4 / r**2

Synchrotron radiation

8

Suppose we increase LEP beam energy (100 GeV) by factor 5: E 500 GeV, in the same tunnel

P ~ E ** 4 / r**2

E increases by factor 5, so P increases by 5**4

this would give P = 5 **4 * 18 MW = 11 GW!

Synchrotron radiation

9

Suppose we increase LEP beam energy (100 GeV) by factor 5: E 500 GeV, in the same tunnel

P ~ E ** 4 / r**2

E increases by factor 5, so P increases by 5**4

this would give P = 5 **4 * 18 MW = 11 GW!

Compensate by increasing radius r?

Need 10 x r to reduce P by 100 270km tunnel!

270km tunnel for e+e- ???

Synchrotron radiation: LHC?

11

Is this a problem for LHC?

Synchrotron radiation: LHC?

12

Is this a problem for LHC?

PSR ~ ( E / m0 ) 4

mproton ~ 2000 * melectron

Pproton ~ 2000-4 * Pelectron for same E

Even for LHC, E = 70 * LEP, each proton loses only

5 keV per turn (0.000 000 1% ~ negligible!)

Large Hadron Collider (LHC)

13

High luminosity is critical

Event rate = luminosity x cross-section

R = L σ

14

High luminosity is critical

Event rate = luminosity x cross-section

R = L σ

σ is ‘probability of something being produced’:

fixed by nature

to maximise R need to maximise L

15

High luminosity is critical

Event rate = luminosity x cross-section

R = L σ

σ is ‘probability of something being produced’:

fixed by nature

to maximise R need to maximise L

For a collider, L = N1 N2 frep / ( 4π σx σy )

N1 particles/bunch of type 1 collide with N2 /bunch of type 2

frep is the bunch collision frequency

σx (σy) is the bunch size in x (y) at the interaction point

16

LHC luminosity

L = N1 N2 frep / ( 4π σx σy )

N1 = N2 ≈ 1011 protons per bunch

frep = 2808 x 11,000

σx,y ≈ 16 μm (best)

L = 1011 1011 2800 11,000 / ( 4π 1.62 10-3 10-3 )

≈ 1034 / cm2 / s

Ignored crossing angle (300 240 urad) …

This needs to be taken account of for precisely evaluating L

17

18CERN roadmap: High Energy frontiers

CLIC Workshop 2015

26-30 September 2015 - CERN

The HL-LHC Project

• New IR-quads Nb3Sn (inner triplets)

• New 11 T Nb3Sn (short) dipoles

• Collimation upgrade

• Cryogenics upgrade

• Crab Cavities

• Cold powering

• Machine protection

• …

Major intervention on more than 1.2 km of the LHC

Project leader: Lucio Rossi; Deputy: Oliver Brüning

F. Bordry

High Energy LHC (HE-LHC)?

19

Challenge:

High-field

magnets

16T

Future circular collider (FCC)?

~ 100km tunnel

16T dipoles

40-50 TeV p beams

e- beams up to

~ 175 GeV

(limited by SR)

Future circular collider (FCC)?

Future circular collider (FCC)?

Future circular collider (FCC)?

Future circular collider (FCC)?

Future circular collider (FCC)?

Future circular collider (FCC)?

Future circular collider (FCC)?

Future circular collider (FCC)?

Future circular collider (FCCee)?

Future circular collider (FCCee)?

Future circular collider (FCCee)?

Future circular collider (FCCee)?

Future circular collider (FCCee)?

Future circular collider (FCCee)?

Very HE-LHC in future 100km tunnel??

Possible CEPC sites

CEPC SPPC ?

Luminosity vs. energy, circular vs. linear

Attempt to summarise: e+e-

39

ILC: 250 GeV 500 GeV? 1000 GeV??

CLIC: 380 GeV 1500 GeV? 3000 GeV??

CEPC/ 250 GeV 350 GeV? 91,180 GeV

FCCee:

Guaranteed precision meas of Higgs (and top)

ILC + CLIC possibility of direct access to HH and ttH

CLIC (+ ILC) possibility of direct access to TeV scale

Attempt to summarise: pp

40

HL-LHC: 7 TeV beams

HE-LHC: 13? TeV beams

FCC/SPPC: 40-50? TeV beams

As of today, we do not know if this extra energy reach is required or enough, let alone optimal!

Development of accelerators

Acceleration in a cylindrical cavity

z

zE0

E(z)

)(tE

g

R. Schmidt

TM 010 mode

43

Typical accelerating cavities

44

State of the art accelerating cavities

ILC goal: 35 MV / m

CLIC goal: 100 MV / m

SCRF Linac Technology

Approximately 20 years of R&D

Worldwide Mature technology

* site dependent

45

1.3 GHz Nb 9-cell Cavities 16,024

Cryomodules 1,855

SC quadrupole package 673

10 MW MB Klystrons &

modulators436 / 471*

• solid niobium

• standing wave

• 9 cells

• operated at 2K (Lqd. He)

• 35 MV/m

• Q0 ≥ 1010

European XFEL @ DESY

46

Largest

deployment of

SCRF

technology

- 100

cryomodules

- 800 cavities

- 17.5 GeV

The ultimate ‘integrated

systems test’ for ILC.

Commissioning with beam

started 2017

Industrial production - XFEL

47

(Thanks to Nick Walker)

One vendor following ILC baseline recipe

quench limit

Field emission

Limit (XFEL spec.)

require

retreatment

status:01.06.2016

TDR

acceptance

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Maximum

Usable

0 10 20 30 40 500%

20%

40%

60%

80%

100%

0

5

10

15

20

25

30

35

Gradient (MV/m)

yie

ld

co

unt

CLIC gradient status

48

• Achieved 100 MV/m gradient in main-beam RF cavities

Electron accelerator development

49

E167

Electron accelerator development

50

E167

wakefield accelerators

Laser wakefield accelerators

51

Can create

electric fields

10-100 GV / m

Beam-driven plasma wakefield accelerators

52

Some e- had their

energy doubled

to c. 80 GeV

in 1m of plasma

40 GeV

Wim Leemans and Eric Esarey, Physics Today, March 2009

Concept of TeV e+e- collider based on laser-plasma

acceleration

Concept for beam-driven Plasma Wake Field TeV

Linear Collider

Drive beam accelerator

DR e- DR e+ main beam e-

injector main beam e+

injector

Beam Delivery and IR

PWFA cells

RF gun

RF separator

bunch compressor Drive beam distribution

PWFA cells

We have a long way to go …

55

100 MeV gamma ray

bursts detected from

crab nebula

1015 eV electrons!

Not to mention 1020 eV (50J) cosmic rays!