CLIC OverviewCLIC Overview
Andrea Latina (APC/FNAL)for the CLIC/CTF3 Collaboration
June 10, 2009 - Low Emittance Muon Collider Workshop, FNALJune 10, 2009 - Low Emittance Muon Collider Workshop, FNAL
OutlineOutline
• Introduction– Physics Case– Linear Colliders
• CLIC– Introduction and main challenges– The two beam accelerator scheme– CLIC technological issues
• CTF3 – CLIC Test Facility– Recent achievements
• Summary
High Energy Physics after LHCHigh Energy Physics after LHC
ICFA: International Commitee for Future Accelerators
Linear Collider e+e- Physics
• Higgs physics– Tevatron/LHC should discover Higgs
(or something else)– LC explores its properties in detail
• Supersymmetry– LC will complement the LHC
particle spectrum• Extra spatial dimensions• New strong interactions
• . . . => a lot of new territory to discoverbeyond the standard model
• Energy can be crucial for discovery
• “Physics at the CLIC Multi-TeV Linear Collider”CERN-2004-005
• “ILC Reference Design Report – Vol.2 – Physics at the ILC” www.linearcollider.org/rdr
Linear versus Circular Colliders Linear versus Circular Colliders
Storage Rings• Acceleration+collision every
turn• “re-use” RF• “re-use” particles efficient Synchrotron Radiation Losses
Luminosity Event rate
Linear Collider• One-pass acceleration+collision• RF used only once• Particles dumped at each
collision need high acceleration gradient need small beam sizes at IP
~40 MHz ~10 Hz
m2 nm2
nb = bunches/trainN = particles per bunchfrep = repetition frequencyx,y = sizes of the beam at IPHD = beam-beam enhancement factor
~1034 cm-2 s-1
Main Challenges for a LC
• High Ecm : long linac / high gradients• nanometer beam sizes at the Interaction Point• Small emittance generation and preservation • Stabilization and Final Focusing
11stst challenge: H challenge: High Gradientsigh Gradients
• Super conducting SW cavities : high efficiency, long pulse, gradient ~35 MV/m, but long filling time
• Normal conducting cavities : high gradients (with traveling wave structures), high frequency, short filling time, short pulse
RF ‘flows’ with group velocity vG along the structure into a load at the structure exit
pulsed RFPowersource
dRF load
Main linac
22ndnd challenge: interaction point beam sizes challenge: interaction point beam sizes
(picture from A. Seryi, ILC@SLAC)(picture from A. Seryi, ILC@SLAC)
(values for CLIC, 11/2008(values for CLIC, 11/2008
Vertical size is smallest
Dyx
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2
4
1
4400045
In order to maximize the luminosity we need very small beam sizes at the interaction point and a flat beam
))
IP
33ndnd challenge: emittance challenge: emittance
Key concept in linear colliders: Generation and preservation of very small emittance!
Generation of small emittances: synchrotron radiation damping -> damping rings
Preservation of small emittances: precision alignment and steering, limitation of collective effects (synchrotron radiation, wake fields)
)()( ss rms
Beam quality
Lattice
RMS beam sizeRMS beam size
RTMLMain linacBeam Delivery
Damping Rings
Source
CLIC: Compact Linear ColliderCLIC: Compact Linear Collider
Centre of mass energy 3 TeV
Luminosity (in 1% energy) 2x1034 cm-2 s-1
Repetition rate 50 Hz
Loaded accelerating gradient 100 MV/m
Main linac RF frequency 12 GHz
Overall two-linac length 41.7 km
Bunch charge 4·109
Beam pulse length 240 ns
Average current in pulse 1 A
Hor./vert. normalized emittance 660 / 20 nm rad
Hor./vert. IP beam size before pinch 45 / ~1 nm
Total site length 48.25 km
Total power consumption 400 MW
Key parameters:
Goals of the study:
CLIC at different energiesCLIC at different energies
3 TeV Stage
Linac 1 Linac 2
Injector Complex
I.P.
3 km20.8 km 20.8 km 3 km
48.2 km
Linac 1 Linac 2
Injector Complex
I.P.
7.0 km 7.0 km
1 TeV Stage
0.5 TeV StageLinac 1 Linac 2
Injector Complex
I.P.
4 km
~14 km
4 km
~20 km
CLIC schematic layout @ 3 TeVCLIC schematic layout @ 3 TeV
Drive beam
The CLIC Two-Beam AcceleratorThe CLIC Two-Beam Accelerator
main beam 1 A, 156 ns9 GeV - 1.5 TeV
DRIVE BEAM
PROBE
BEAM
Why a two-beam scheme?Why a two-beam scheme?
• Luminosity scales as wall-plug-to-beam efficiency. Need to obtain: high-gradient acceleration and efficient energy transfer.
• High-frequency RF maximizes the electric field in the RF cavities for a given stored energy.
• However, standard RF sources scale unfavorably to high frequencies, both in for maximum delivered power and efficiency.
• A way to overcome such a drawback is to use standard low-frequency RF sources to accelerate the drive beam and then use it to produce RF power at high frequency.
• The drive beam is therefore used for intermediate energy storage.
Dyx
repb HfNn
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2
4
Dyx
AC HNP**
Luminosity
Drive Beam IdeaDrive Beam Idea
• Very high gradients possible with NC accelerating structures at high RF frequencies (30 GHz → 12 GHz)
• Extract required high RF power from an intense e- “drive beam”• Generate efficiently long beam pulse and
compress it (in power + frequency)
Long RF PulsesP0 , 0 , 0
Short RF PulsesPA = P0 N1
A = 0 / N2 A = 0 N3
Electron beam manipulation
Power compressionFrequency multiplication
‘few’ KlystronsLow frequencyHigh efficiency
Accelerating StructuresHigh Frequency – High field
Power stored inelectron beam
Power extracted from beamin resonant structures
Two Beams schemeTwo Beams scheme
CLIC acceleration systemCLIC acceleration system
Why 100 MV/m at 12 GHz?Why 100 MV/m at 12 GHz?
Accelerating structuresAccelerating structures
Best Result so far..Best Result so far..
Power Extraction Transfer Structures - Power Extraction Transfer Structures - PETSPETS
CLIC Accelerating ModuleCLIC Accelerating Module
Getting the Luminosity (>2 x10Getting the Luminosity (>2 x103434 cm cm-2-2ss-1-1))
Low emittance generationLow emittance generation
Many other issues besides intra-beam scattering : fast-ion instability and e-cloud (being mitigated using different coating for the vacuum chamber, tests at CESR-TA summer 2009), wiggler design..
Damping Ring EmittancesDamping Ring Emittances
Rings to Main LinacRings to Main Linac
RTML includes:
•BC1 stage: bunch length from 5 mm to 1.5 mm at 2.4 GeV
•Booster linac from 2.4 to 9 GeV
•Transfer line and turnaround loops
•BC2 stage: from 1.5 mm to 44 microm
=> max 5 nm vertical emittance growth is allowed
First partcle tracking through the complete system
20 km
boos
ter
Emittance Preservation in the Main LinacEmittance Preservation in the Main Linac
Vertical emittance growth bugdet is 10 nm
Emittance Preservation in the MLEmittance Preservation in the ML
Example for cavity misalignmentExample for cavity misalignment
Static Imperfections in the MLStatic Imperfections in the ML
Beam Delivery SystemBeam Delivery System
Optics design for the 3 TeV option (alternative design for 0.5 TeV exists)
Interaction Region
Final Focus QD0 StabilizationFinal Focus QD0 Stabilization
QD0 must be stabilized to 0.15 nm for frequencies above 4 Hz
Active Stabilization StudiesActive Stabilization Studies
0.13 nm have been reached in laboratory, the challenge remains to prove 0.15 nm within the detector
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Conceptual Design Report (CDR) - end 2010Conceptual Design Report (CDR) - end 2010
The CLIC CDR should address the critical points:
• Accelerating structures at 100 MV/m
• Power Extraction and Transfer Structures (PETS)
• Generation of the 100 A drive beam with 12 GHz bunch frequency
• meeting the phase, energy and intensity stability tolerances
• Main beam low emittances
• Stabilization of main quads. to 1nm and FD quads to 0.15nm (freqs>4 Hz)
• Machine protection issues
=> Test facilities at CERN: CTF3 / CLEX
CTF3: Drive Beam Test-BenchCTF3: Drive Beam Test-Bench
Drive beam
CLIC R&D issues: CTF3/CLEXCLIC R&D issues: CTF3/CLEX
CTF3 is a small scale version of the CLIC drive beam complex: Provide the RF power to test the CLIC accelerating structures and components Full beam-loading accelerator operation Electron beam pulse compression and frequency multiplication Safe and stable beam deceleration and power extraction High power two beam acceleration scheme
Current Status of CTF3Current Status of CTF3
39EPAC 2008 CLIC / CTF3 G.Geschonke, CERN
existing building
D FFD
D F D
D F D D F D
D F D
DF DF DF DF DF DF DF DF DF
D F D
F DF D
D FFFDD
D F DD F D
D F DD F D D F DD F D
D F DD F D
DF DF DF DF DF DF DF DF DF DFDF DF DF DF DF DF DF DF DF DF DF DF DF DF DF DF
D F DD F D
F DF DF DF D
42.5 m
8 m
2m
D FFD
D F DDUMPD F D
ITB
1.85m
CALIFES Probe beam injector
LIL-ACSLIL-ACSLIL-ACSD F D
D F D
DFDUMP
0.75
1.4m
1
DUMP
22.4 mTBL
2.5m
Transport path
22 m
2.0m
DF DF DF DF DF DF DF DF
3.0m3.0m6 m
D F D
F DF D
16.5 mTBTS
16 m
TL2’
42.5 m42.5 m
8 m
8 m
2m2m
D FFFDD
D F DD F DDUMPD F DD F D
ITB
1.85m1.85m
CALIFES Probe beam injector
LIL-ACSLIL-ACSLIL-ACSLIL-ACSLIL-ACSLIL-ACSD F DD F D
D F DD F D
DF DFDUMP
0.75
1.4m1.4m
11
DUMP
22.4 m22.4 mTBL
2.5m2.5m
Transport path
22 m22 m
2.0m2.0m
DF DF DF DF DF DF DF DFDF DF DF DF DF DF DF DF DF DF DF DF DF DF DF DF
3.0m3.0m3.0m3.0m6 m6 m
D F DD F D
F DF DF DF D
16.5 m16.5 mTBTS
16 m16 m
TL2’
Test Beam Line TBL
CLEX building
Jan 2008
Jan 2008
September 2006June 2006
June 2008
Probe Beam linac
June 2008Two Beam Test Stand
(University Uppsala)
Equipment installed (except TBL),Beam foreseen from June 2008
CTF3: full beam loadingCTF3: full beam loading
Delay LoopDelay Loop
Combiner RingsCombiner Rings
CTF3: x 4 combination in CRCTF3: x 4 combination in CR
CTF3: Power Extraction and RecirculationCTF3: Power Extraction and Recirculation
•The first 12 GHz PETS was tested with BEAM in November and December last year•Recirculation of the output field was used, to produce more power from the 5A CTF3 current•30 MW of RF power were generated (plot shows 25 MW)•RF signal was reproduced using BPM intensity signal
PETS shows excellent behaviour and agreed with design performanceThis also means that the this is a very good test-bench to test PETS in two-beam acceleration
SummarySummary
•Excellent progress towards the CLIC CDR (2010)
•Technical program is on track
• but lots of work still to be done.
• Challenging work and tight schedule!
LHC results
The CTF3 – CLIC world wide collaboration
46EPAC 2008 CLIC / CTF3 G.Geschonke, CERN
Helsinki Institute of Physics (Finland) IAP (Russia)IAP NASU (Ukraine)Instituto de Fisica Corpuscular (Spain)INFN / LNF (Italy)J.Adams Institute, (UK)JINR (Russia)
Oslo University (Norway)PSI (Switzerland),Polytech. University of Catalonia
(Spain)RRCAT-Indore (India)Royal Holloway, Univ. London, (UK) SLAC (USA)Uppsala University (Sweden)
Ankara University (Turkey)BINP (Russia)CERNCIEMAT (Spain)Cockcroft Institute (UK)Gazi Universities (Turkey)IRFU/Saclay (France)
JLAB (USA)Karlsruhe University (Germany)KEK (Japan) LAL/Orsay (France) LAPP/ESIA (France)NCP (Pakistan)North-West. Univ. Illinois (USA)
28 institutes involving 18 funding agencies from 16 countries