the european laser projectthe european laser project xfel and ilc · 2009-11-16 · ilc 2x10 34 5...

ILC-ECFA Workshop 2008Warsaw 9-12 June 2008

The European Laser ProjectThe European Laser Project XFEL and ILC

Carlo PaganiUniversity of Milano and INFN Milano-LASA

Index

Introduction: why accelerators as source for neutrons?– General principles of neutron production with accelerators

What is a high power accelerator and how does it work?– General layout– Superconductive choice

Applications of accelerator driven neutron sourcesApplications of accelerator driven neutron sources– Waste Transmutation (ADS)– Materials studies (SNS)

F i (IFMIF)– Fusion (IFMIF)

ILC-ECFA WorkshopWarsaw, 9 June 2008

Carlo Pagani2

Energy Frontier and Accelerator Tech.

Superconducting Magnets

ILC ∅ = 38”

Superconducting RF Cavities

LHC Dipole String

ACC 4 & ACC 5 in TTF

∅ = 38”ILC Cavity String


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ILC Cavity String


Superconducting Dipoles

ILC ∅ = 38”


LHC Dipole String

ACC 4 & ACC 5 in TTF

∅ 38”∅ = 38”

I C C i S i


Carlo Pagani4

ILC Cavity String

No Circular e+e- Collider after LEP

Synchrotron Radiation:charged particle in a magnetic field: Energy loss dramatic for electrons

B [ ] [ ]kmr1106GeV 421 ⋅⋅⋅= − γSRU

USR = energy loss per turnγ = relativistic factorr = machine magnetic radius

γproton / γelectron ≈ 2000

Energy loss replaced by RF powercost scaling $ ∝ E 2


Carlo Pagani5

cost scaling $ ∝ Ecm2

A Simple Exercise

Synchrotron Radiation (SR) becomes prohibitive for electrons in a circular machine above LEP energies:

[ ] 1421UUSR = energy loss per turn

RF system must replace this loss, and r scale as E2

[ ] [ ]kmr1106GeV 421 ⋅⋅⋅= − γSRU SR gy p

γ = relativistic factorr = machine radius

LEP @ 100 GeV/beam: 27 km around, 2 GeV/turn lostPossible scale to 250 GeV/beam i.e. Ecm = 500 GeV:– 170 km around

γ250GeV = 4.9 . 105

– 13 GeV/turn lostConsider also the luminosity– For a luminosity of ~ 1034/cm2/second, scaling from b-factories gives

~ 1 Ampere of beam current– 13 GeV/turn x 2 amperes = 26 GW RF power– Because of conversion efficiency, this collider would consume more power

than the state of California in summer: 45 GW

Circulating beam power = 500 GW


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than the state of California in summer: ~ 45 GWBoth size and power seem excessive

Origin of the Linear Collider Idea

M. Tigner, Nuovo Cimento 37 (1965) 1228

A Possible Apparatus for Electron-Clashing Experiments (*).

M. TignerM. TignerLaboratory of Nuclear Studies. Cornell University - Ithaca, N.Y.

“While the storage ring concept for providing clashing-beam experiments (1) is very elegant in concept it seems worth while at the present juncture to investigate otherworth-while at the present juncture to investigate other methods which, while less elegant and superficially more complex may prove more tractable.”


Carlo Pagani7

Linear Collider Conceptual Scheme

Main LinacAccelerate beam

Final FocusDemagnify and collide beams

Bunch CompressorReduce σz to eliminate hourglass effect at IP

Accelerate beam to IP energy without spoiling DR emittance

Damping RingReduce transverse phase space (emittance) so smaller

IP i hi bl

Electron GunDeliver stable beam

transverse IP size achievablePositron TargetUse electrons to pair-produce positrons


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Deliver stable beam current

Fighting for Luminosity

2e

σσNL ∝ xσ repb fnL ×∝

NPnb = # of bunches per pulse

frep = pulse repetition rate

L = Luminosity

Ne = # of electron per bunch

yxσσyσ

p

yx

e

c.m.

b

σσN

EPL ×∝

Pb = beam power

Ec.m.= center of mass energy

σx,y = beam sizes at IP

IP = interaction point

Parameters to play withReduce beam emittance (εx

.εy ) for smaller beam size (σx.σy ) x y x y

Increase bunch population (Ne )Increase beam powerI b t l ffi i f t

( )repbb fnNP ××∝ e


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Increase beam to-plug power efficiency for cost

Competing technologies for the ILC

Evolution from: SLAC & SLC

1.3 GHz - Cold

Evolution from: CEBAF & LEPII

11.4 GHz - Warm

+ TRISTAN, HERA, etc.


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30 GHz-Warm12 GHz - Warm

Beam Sizes: Pictorial View

© M. Tignerg


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LC Organisation up to August 2004


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Technology Choice:NLC/JLC or TESLA

The International Linear Collider Steering Committee (ILCSC) selected the twelve members of the International Technology Recommendation Panel (ITRP) at the end of 2003:Recommendation Panel (ITRP) at the end of 2003:

Asia:G.S. Lee

Europe:J-E Augustin

North America:J. Bagger

A. MasaikeK. OideH. Sugawara

gG. BellettiniG. KalmusV. Soergel

ggB. Barish (Chair)P. GrannisN. Holtkampg g p

First meeting end of January 2004 at RAL

Mission: one technology by end 2004

Result: recommendation on 19 August 2004


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g

From the ILC Birthday


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From the ILC Birthday


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The ILC technology choiceStanding wave: Vph = 0 and Vg = 0

TESLA: f = 1.3 GHz

Remembering that the power dissipated on the cavity walls to sustain a field is:

∫= sdiss dSHRP 2

2standing wave case

π mode

∫S

diss 2a pulsed operation is required to reduce the time in which the maximum allowable field is produced to accelerate the particlesThe power is deposited at the operating produced to accelerate the particles

1 0E 05

1.0E-04

1.0E-03

and

Cu

Rs

The power is deposited at the operating temperature of 2 K

We need to guarantee and preserve the 2 K environment

1.0E-07

1.0E-06

1.0E-05

Rat

io b

etw

een

Nb

2 K4.2 K

environmentCavity is sensitive to pressure variations, only viable environment is sub-atmospheric vapor saturated He II bath

1.0E-080 500 1000 1500 2000 2500 3000

f [MHz]

RWe need a thermal “machine” that performs work at room temperature to extract the heat deposited at cold

We can’t beat Carnot efficiency!


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We can t beat Carnot efficiency!Cryogenics and cryomodules

How is spent the cold advantage?

The gain in RF power dissipation with respect to a normal-conducting structure is spent in different ways

TTPaying the price of supplying coolant at 2K

– This include ideal Carnot cycle efficiencyMechanical efficiency of compressors and refrigeration items

c

ch

TTT

QW−

≥

– Mechanical efficiency of compressors and refrigeration items– Cryo-losses for supplying and transport of cryogenics coolants– Static losses to maintain the linac cold

Increasing of the duty cycle (percentage of RF field on)– Longer beam pulses, larger bunch separation, but also– Larger and more challenging Damping Rings

Increasing the beam power (for the same plug power)


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– Good for Luminosity

Linear Colliders are pulsed

LCs are pulsed machines to improve efficiency. As a result: • duty factors are small• pulse peak powers can be very largep p p y g

RF Pulse<10 200 ms

<1 µs-1ms

RF Pulse<10-200 ms

Bunch Train1-300 nsec

100 m - 300 km…………………....

……

gradient

Beam Loading

gradientwith further input

without inputaccelerating field pulse:


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filling loading

The TESLA Collaboration Mission

Develop SRF for the future TeV Linear ColliderBasic goals

• Increase gradient by a factor of 5 (Physical limit for Nb at ~ 50 MV/m)• Increase gradient by a factor of 5 (Physical limit for Nb at ~ 50 MV/m)• Reduce cost per MV by a factor 20 (New cryomodule concept and Industrialization)• Make possible pulsed operation (Combine SRF and mechanical engineering)

Major advantages vs NC Technologyj g gy• Higher conversion efficiency: more beam power for less plug power consumption• Lower RF frequency: relaxed tolerances and smaller emittance dilution

as in 1992


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Björn Wiik

TESLA Collaboration MilestonesInfrastructure

@ DESY in Hall 3February 1992 – 1 TESLA Collaboration Board Meeting @ DESYMarch 1993 - “A Proposal to Construct and Test P t t S d ti RF St t f

TTF I

Prototype Superconducting RF Structures for Linear Colliders”1995 – 25 MV/m in multi-cell cavityMay 1996 – First beam at TTF

TESLA Collider

May 1996 First beam at TTFMarch 2001 – First SASE-FEL Saturation at TTFMarch 2001 – TESLA Technical Design Report

TESLA X-Ray FELFebruary 2003 –TESLA X-FEL proposed as an European Facility,50% funding from Germany2004 – FLASH (TTF II) Commissioning start

FLASH

2004 FLASH (TTF II) Commissioning startApril 2004 - 35 MV/m with beamAugust 2004 - TESLA Technology chosen for ILC


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June 2007 – Formal start of the XFEL Project

Luminosity & Beam Size

Dyx

repb HfNn

Lσπσ2

2

=

frep * nb tends to be low in a linear collider

y

L frep [Hz] nb N [1010] σx [μm] σy [μm]rep [ ] b [ ] x [μ ] y [μ ]ILC 2x1034 5 3000 2 0.5 0.005SLC 2x1030 120 1 4 1.5 0.5LEP2 5x1031 10,000 8 30 240 4

The beam-beam tune shift limit is much looser in a linear collider than a

,PEP-II 1x1034 140,000 1700 6 155 4

The beam beam tune shift limit is much looser in a linear collider than a storage rings achieve luminosity with spot size and bunch charge– Small spots mean small emittances and small betas:

sqrt (β )


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– σx = sqrt (βx εx)


Dyx

repb HfNn

Lσπσ2

2

=

frep. nb tends to be low in a linear collider

y

L frep [Hz] nb N [1010] σx [μm] σy [μm]

ILC 2x10 34 5 3000 2 0.5 0.005SLC 2x10 30 120 1 4 1.5 0.5LEP-II 5x10 31 10,000 8 30 240 4LEP-II 5x10 10,000 8 30 240 4PEP-II 1x10 34 140,000 1700 6 155 4

The beam-beam tune shift limit is much looser in a linear collider than a storage rings achieve luminosity with spot size and bunch charge– Small spots mean small emittances and small betas:

σ = sqrt (β ε )


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σx = sqrt (βx εx)


Dyx

repb HfNn

Lσπσ2

2

=y

L frep [Hz] nb N [1010] σx [μm] σy [μm] Pb

ILC 2x10 34 5 3000 2 0.5 0.005

SLC 2x10 30 120 1 4 1.5 0.5LEP II 5x10 31 10 000 8 30 240 4LEP-II 5x10 10,000 8 30 240 4PEP-II 1x10 34 140,000 1700 6 155 4


Carlo Pagani23

Start of the Global Design Initiative

~ 220 participants from 3 regionsmost of them accelerator experts


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ILC Pictorial View (TESLA Like)

A t th T h l R d ti ti


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As at the Technology Recommendation time

The Existing FLASH @ DESY


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European Industrial Forum for SCRFp3

.fr/

SCRF

trac

.lal.in2

pht

tps:

//t


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https://indico.desy.de/conferenceTimeTable.py?confId=61

Designing a Linear Collider

source

pre-acceleratorfew GeV

dampingring

final focus

extraction& dump

KeV

few GeVfew GeV

250-500 GeV

main linacbunchcompressor collimation

final focus

IP

few GeV

compressor collimation

Superconducting RF Main Linac


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ILC Road Map


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Conclusions

Present and future large facilities are based to a large extent on the superconducting RF linac technology that has been pioneered for the High Energy Physics machines in the last decadesHigh Energy Physics machines in the last decades

– LEP at CERN (e+e- collider with SRF cavities)– CEBAF at TJNAF (recirculated SRF linac)– TESLA and ILC (next generation linear colliders proposed for

precision physics in the Higgs sector after LHC discovery)

SNS moved from NC design to SC after project approval and during construction

Future facilities rely on SC linacs at even lower energies to benefit from SC technology


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Energy Frontier and e+e- Colliders

LEP at CERNEcm ~ 200 GeVLEP at CERNEcm ~ 200 GeVcmPRF ~ 30 MW

cmPRF ~ 30 MW

ILC


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Superconducting Magnets

ILC


LHC Dipole String


Carlo Pagani32

LEPII Cavity String

the european laser projectthe european laser project xfel and ilc · 2009-11-16 · ilc 2x10 34 5...

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