ctf3 measurements and plans r. corsini for the ctf3 team

R. Corsini, CLIC Project Meeting, 9 Dec 2011

CTF3 measurements and plans

R. Corsini for the CTF3 Team

1

Talk Outline:

1. Summary

2. Status of feasibility benchmarks in CTF3

• Drive beam generation• PETS & RF Structures• Two-beam issues

3. Plans for 2012


Test Beam Line (TBL) in CTF3

• Many improvements on optics, hardware, feed-backs, beam stability, reproducibility…

• PETS operation to power levels (~250 MW) well above CLIC goal, at nominal CLIC pulse length.

• Measured gradient in two-beam acceleration test 145 MV/m (CLIC nominal gradient of 100 MV/m)

• Nine PETS tanks installed in the Test Beam Line (TBL), 20 A decelerated by ~ 25%, matching well with expectations

• First successful test of PETS with on-off mechanism

• First measurements of break-down kicks in TBTS

Two-beam acceleration in TBTS

Optics model checks in Combiner Ring

200 400 600 800 1000

50

100

150

200

250

CLIC target pulse

12 GHz RF power

135 MW

Power Extraction Structure (PETS)

P

[MW

]

t [ns]

CTF3 - 2011


Barranco JavierConstance

BenjaminIkarios EmmanouilPersson TobiasSkowronski PiotrSterbini GuidoBolzon BenoitBurger StephaneFavier MathildeGuillot-Vignot

FranckLefevre ThibautOlvegaard MajaRabiller AurelieSoby LarsDobers TobiasChevallay Eric

Csatari Marta

Fedosseev ValentinHessler Christoph

Putz SvenPaju Esa AnteroAllard DanielMonteiro JoseRavida GianfrancoRey Stephane FranckRinolfi LouisRossat GhislainSyratchev IgorTimeo LucaWiszniowski ThierryFarabolini WilfridPeauger FranckRuber RogerPalaia AndreaGerbershagen

AlexanderMarin Lacoma EduardoLillestol ReidarJacewicz Marek…

Draper MichaelGamba DavideTecker FrankDubrovskiy AlexeyPasinelli SergioRiddone GermanaSamochkine

AlexandreKovermann JanKononenko OlekseyAndersson AlexandraCurt StephaneDoebert SteffenGeschonke GuntherLivesley StephenMcmonagle GerardBarnes Michael JohnHourican MichaelDe Oliveira LoicDavid Nicolas Andre

Many, many thanks to the CTF3 team & all collaborators from within & outside CERN


System Item Feasibility Issue Unit Nominal Achieved How Feasibility CommentsFully loaded accel effic % 97 95 CTF3 Freq&Current multipl - 2*3*4 2*4 CTF3

Combined beam current (12 GHz) A 4.5*24=100 3.5*8=28 CTF3

Combined pulse length (12 GHz) nsec 240 140 CTF3Intensity stability 1.E-03 0.75 < 0.6 CTF3 End of DBA. To be demonstrated for combined beam in 2011

Drive beam linac RF phase stability Deg (1GHZ) 0.05 0.035 CTF3, XFEL Achieved in CTF3, XFEL design

PETS RF Power MW 130 >130 TBTS/SLAC

PETS Pulse length ns 170 >170 TBTS/SLAC

PETS Breakdown rate /m < 1·10-7 ≤ 2.4 10-7 TBTS/SLAC

PETS ON/OFF - @ 50Hz - CTF3/TBTS 2011 Prototype under fabrication for tests with beam

Drive beam to RF efficiency % 90% - CTF3/TBL2012

TBL with 8 (16) PETS in 2011(12) for 30(50%) efficiency. Benchmark beam simulation for safe extrapolation of high efficiency at high drive beam energy(2GeV).

RF pulse shape control % < 0.1% - CTF3/TBTS 2011-2012

Structure Acc field MV/m 100 100Structure Flat Top Pulse length ns 170 170 Structure Breakdown rate /m MV/m.ns < 3·10-7 5·10-5(D) 2011Rf to beam transfer efficiency % 27 15 2011

Power production in Two Beam Test Stand (TBTS)

Probe beam acceleration by Two Beam Test Stand(TBTS)

Drive to main beam timing stability psec 0.05 - CTF3 2012

Main to main beam timing stability psec 0.07 - XFEL? 2012

Emitttance generation H/V nm 500/5 3000/12 Damping Ring design nom perf. Relax emitt achieved ATF

Emittance preservation: Blow-upH/V

nm 160/15 160/15 2011-12 Simulation + alignment/stability

Main Linac components microns 15 2011Final-Doublet microns 2 to 8 2011

Quad Main Linac nm>1 Hz 1.5

Final Doublet (assuming feedbacks) nm>4 Hz 0.2drive beam power [email protected] beam power of [email protected]

Operation and Machine Protection System (MPS)

CTF3 simulations

2011 Report integrating LHC experience under preparation

Principle demonstrated in CTF2, to be adapted to long distances and integrated in Two Beam Module in 2010

Vertical stabilisation

0.13 (principle)

Stabilisation Test Bench

2011-12 Adaptation to quad prototype and detector environment in 2010. Integrated in Two Beam Module with beam till 2012.

2011

Ultra low beam

emittance & sizes

Ultra low Emittances

ATF, NSLS/SLS + simulation

Alignment 10 (princ.) Alignement & Mod.Test Bench

Two Beam Acceleration

Power producton and probe beamacceleration in Two beam module MV/m - ns 100 - 170 106 - 170 TBTS


Drive beam generation

Accelerating Structures

(CAS)

CTF3 Test Stand, SLAC,

KEK

Nominal performances of 3 structures without damping. 1 structure equipped with damping features under RF conditionning to reduce breakdown rate.

Novel scheme fully demonstrated in CTF3 in spite of lower current since beam dynamics more sensitive than nominal

due to lower energy (250MeV/2Gev)

Beam Driven RF

power generation

BD rate at nominal power and pulse lenght, measured on Klystron driven PETS. Beam driven tests under way in CTF3

System Item Feasibility Issue Unit Nominal Achieved How Feasibility CommentsFully loaded accel effic % 97 95 CTF3 Freq&Current multipl - 2*3*4 2*4 CTF3

Combined beam current (12 GHz) A 4.5*24=100 3.5*8=28 CTF3

Combined pulse length (12 GHz) nsec 240 140 CTF3Intensity stability 1.E-03 0.75 < 0.6 CTF3 End of DBA. To be demonstrated for combined beam in 2011

Drive beam linac RF phase stability Deg (1GHZ) 0.05 0.035 CTF3, XFEL Achieved in CTF3, XFEL design

PETS RF Power MW 130 >130 TBTS/SLAC

PETS Pulse length ns 170 >170 TBTS/SLAC

PETS Breakdown rate /m < 1·10-7 ≤ 2.4 10-7 TBTS/SLAC

PETS ON/OFF - @ 50Hz - CTF3/TBTS 2011 Prototype under fabrication for tests with beam

Drive beam to RF efficiency % 90% - CTF3/TBL2012

TBL with 8 (16) PETS in 2011(12) for 30(50%) efficiency. Benchmark beam simulation for safe extrapolation of high efficiency at high drive beam energy(2GeV).

RF pulse shape control % < 0.1% - CTF3/TBTS 2011-2012

Structure Acc field MV/m 100 100Structure Flat Top Pulse length ns 170 170 Structure Breakdown rate /m MV/m.ns < 3·10-7 5·10-5(D) 2011Rf to beam transfer efficiency % 27 15 2011

Power production in Two Beam Test Stand (TBTS)

Probe beam acceleration by Two Beam Test Stand(TBTS)

Drive to main beam timing stability psec 0.05 - CTF3 2012

Main to main beam timing stability psec 0.07 - XFEL? 2012

Emitttance generation H/V nm 500/5 3000/12 Damping Ring design nom perf. Relax emitt achieved ATF

Emittance preservation: Blow-upH/V

nm 160/15 160/15 2011-12 Simulation + alignment/stability

Main Linac components microns 15 2011Final-Doublet microns 2 to 8 2011

Quad Main Linac nm>1 Hz 1.5

Final Doublet (assuming feedbacks) nm>4 Hz 0.2drive beam power [email protected] beam power of [email protected]

Operation and Machine Protection System (MPS)

CTF3 simulations

2011 Report integrating LHC experience under preparation

Principle demonstrated in CTF2, to be adapted to long distances and integrated in Two Beam Module in 2010

Vertical stabilisation

0.13 (principle)

Stabilisation Test Bench

2011-12 Adaptation to quad prototype and detector environment in 2010. Integrated in Two Beam Module with beam till 2012.

2011

Ultra low beam

emittance & sizes

Ultra low Emittances

ATF, NSLS/SLS + simulation

Alignment 10 (princ.) Alignement & Mod.Test Bench


Power producton and probe beamacceleration in Two beam module MV/m - ns 100 - 170 106 - 170 TBTS


Drive beam generation

Accelerating Structures

(CAS)

CTF3 Test Stand, SLAC,

KEK

Nominal performances of 3 structures without damping. 1 structure equipped with damping features under RF conditionning to reduce breakdown rate.

Novel scheme fully demonstrated in CTF3 in spite of lower current since beam dynamics more sensitive than nominal

due to lower energy (250MeV/2Gev)

Beam Driven RF

power generation

BD rate at nominal power and pulse lenght, measured on Klystron driven PETS. Beam driven tests under way in CTF3

CTF3

CLIC Feasibility Benchmarks

4

Technical system tests and

simulations

RF Test StandsSLAC – KEK -CERN

Nextef – RF test stand KEK


High current, full-loaded linac operation

• 95 % RF to beam efficiency measured

• No instabilities

High current, full-loaded linac operation

• 95 % RF to beam efficiency measured

• No instabilities

10 m

RF pulse at output

RF pulse at structure input

1.5 µs beam pulse

Achievements – Drive Beam Generation

MKS03 MKS07MKS06MKS05

Spectrometer 10Spectrometer 4SiC load

damping slot

Dipole modes suppressed by slotted iris damping (first dipole’s Q factor < 20)and HOM frequency detuning

R. Corsini, CLIC Project Meeting, 9 Dec 2011Achievements – Drive Beam Generation

Beam recombination

• Fast bunch phase switch in SHB system

• Operation of isochronous rings and beam lines


333 ps

Streak camera image of the beam, illustrating the bunch combination process

t

x

83 ps



Beam recombination

• Factor 8 recombination by RF deflector injection

Beam recombination

• Factor 8 recombination by RF deflector injection

P0 , n0

P0 , f 0

2 × P0 , 2 × f 0

TransverseRF Deflector, f 0

DeflectingField

6 & 7 December 2011

6 & 7 December 2011


Problems: • TWT availability – still working with 2 SHB only – plus day-to-day power fluctuations

• Mainly working with 3 GHz beam for most of the year

• Difficult DL set-up after last stop – suspect misaligned quadrupole (+ radiation alarm problem)

Eventually able to get good recombination (current record), but:

• Bad pulse shape (phase switches?)

• Still limited acceptance -> stability was improved, but it is still not good enough

Future work:

• Measure and realign DL quad(s)

• Work on phase switches, gun current compensation, back to 3 TWTs, improve trajectories


P. Skowronski

DL current

H

V


Beam recombination - Emittance

Best results in CLEX for factor 4: eH= 250 um eV= 140 um

for factor 8: eH= 640 um eV= 170 um

Different turns are ~ ok, no unknown effectsEmittance increase due to non perfect combination


• Improve measurements• Correct dispersion (linear,

nonlinear)• Correct multi-turn orbit• Control beta-beating

End 2011 ?

Horiz. Vert.

Measurements in TL2 - uncombined

Uncombined beam


Vertical Horizontal

Factor 4 Factor 8 Factor 4 Factor 8

Emittance – last measurements in CLEX • No time for optimization

• Main issue: different trajectories for DL & bypass beams and ring orbit closure (differences of the order of 1 s)

• Vertical: main effect from DL, small effect from ring• Horizontal: ring closure is dominant

• Similar Twiss parameters for factor 4 and factor 8 combination (small betatron mismatch)


F. Tecker, P. Skowronski, S. Doebert, R. Lillestol


Factor 4Factor 8

B. Constance


Beam profile during emittance measurements

Improved quad scan

program


• Improve measurements• Tune chicane to small R56• Measurements in CLEX

End 2011 ? Improve in 2012

Beam recombination – Bunch lenght

nominal in CLEX 1 mm sigma

In the past, well below 1 mm sigma measured at the end of the linac (tuned chicane)

Recent results (preliminary): 1.5 to 4 mm sigma for CR and CLEX (natural chicane)



Phase stability 2.5° @ 12GHz0.2° @ 1GHz

Phase stability 2.5° @ 12GHz0.2° @ 1GHz

Emittance εx,y ≤ 150μm

Transverse jitter ≤ 0.3σ

Emittance εx,y ≤ 150μm

Transverse jitter ≤ 0.3σ

Current stability 0.75 10-3

Phase stability 0.2° @ 12GHz

Bunch length stability 1%

Current stability 0.75 10-3

Phase stability 0.2° @ 12GHz

Bunch length stability 1%

RF power stability 0.2%RF phase stability 0.05°Current stability 0.1%

RF power stability 0.2%RF phase stability 0.05°Current stability 0.1%

CLIC Drive Beam requirements


Pulse charge measured at end of the linac

After factor 8 combination~ 1% jitter

Tolerance

Measured

Beam current

0.075% 0.054%

RF Power 0.2% 0.16% - 0.21%

RF Phase 0.05° 0.035° - 0.07°

“Good” CTF3 klystron

• pulse-to-pulse jitter• 10 ns time slices along the RF

pulse• with respect to local phase

reference• Improve and document current

stability for combination factor 4• Improve stability for combination

factor 8 – at the permil level• Means: improve acceptance

(dispersion, orbit, beta-beating)• Reduce energy spread – bunch

length

End 2011 – Mid 2012 G. Sterbini, A. Dubrovsky


5 10-4

1 10-3

3 to 4 10-3


Charge stability – Factor 4

18th November 2011

T. Persson


Total loss from cleaning chicane to TBTS ~ 15% BPM

s

BPIs

T. Persson18th November 2011

Charge losses – Factor 4



Charge stability – Factor 8

1 10-2

6th December 2011

T. Persson


DL ~ 1 10-3


Charge stability – Factor 4with noise estimate

T. Persson 6th December 2011

< 1 10-3



[MW

][a

rb]

Feed-backs, stability

RF power feedback, MKS 13RF power feedback, MKS 13

Tobias Persson, Piotr Skowronski



Feed-backs, stabilityRF power feedback, effect on beam

RF power feedback, effect on beam

Tobias Persson, Piotr Skowronski


R. Corsini, CLIC Project Meeting, 9 Dec 2011Achievements – Beam driven RF power generation

PETS rapidly (~ 3 x 105 pulses) reached record >200 MW peak RF power level,

providing reliably pulses ~ 1o0 MW peak to accelerating structure.

About twice the power needed to demonstrate 100 MV/m acceleration in a two-beam experiment with TD24 structure.

22

Breakdown rate ?

• Analyze data for evaluation of present break-down rate

• Dedicated measurement at high powers – increased rep rate

• Document

End 2011 – Mid 2012

200 400 600 800 1000

50

100

150

200

250

CLIC target pulse


23

On-off mechanism

Installation in CTF3 TBTS under way now.Test starting from next week.

Issues:

• Reliable power production

• Ability to control output power

• Conditioning• Initial test – no structure

connected• Connect structure• Full test, including use as

recirculation loop

End 2011 ?


Igor Syratchev, Alexei Dubrowski

Power to the structure

Power extracted from the drive beam

ON

OFF

Achievements – Beam driven RF power generation

In CTF3 a movable short is added, to allow for recirculation mode

PETS On-Off concept


ONOFF

PETS outputStructure input

(as predicted by computer simulation)

TBTS PETS layout with internal recirculation to test the ON/OFF concept

Movable RF short circuit (to tune the resonant length)

Variable reflector (to tune the recirculation coupling)

Igor Syratchev



30 October (logbook pictures)

Power

PMT signal

Current

45 MW

150 MW

80 MW

CTF3 Achievements – Beam driven RF power generation


PETS On-Off conditioning

Vacuum gauges

Peak power

Pulse length at 50% level

R. Corsini, CLIC Project Meeting, 9 Dec 2011CTF3 Achievements – Beam driven RF power

generation


PETS On-Off operation – high current, high power


Simulation vs. experiment


0N

0FF

Combination x 4 0N

0FF

0N

0FF

Beam current PETS, forward RF

RF to structurePETS, reflected RF

Signal evolution during On-Off


PETS On-Off mechanism - results

PETS output, forward

Spectra comparison


29

16 PETS maximum

4 PETS installed and tested4 5 being installed in September12 to 16 next year

50 100 150 200 250 300 350 400 450108

110

112

114

116

118

120

122

time (ns)

Be

am

En

erg

y (

Me

V)

Prediction from rf power

Prediction from beam currentSegmented dump measurement

Up to 19 A current

• optics understood• no losses in TBL

Good agreement

• power production

• beam current• beam deceleration

• Deceleration with 9 PETS, 20 A (end 2011)

• Deceleration with 12 PETS, > 20 A (mid 2012)

• Final test, 16 PETS (end 2012)

9 PETS – 20 ANovember 2011

9 PETS – 20 ANovember 2011


Steffen Doebert, Reidar Lillestol

TBLTL2


High current transport in TBL

Factor 4

Factor 8

Factor 8


Reidar Lillestol

High current power production in TBL

More than half a GW of 12 GHz power!


~ 30 MeV

25%

Incoming energy 117 MeV, field form factor 0.9 (average) Steffen Doebert



33

CLIC target pulse

Beam loading compensation ramp

• Create precise ramp by fine tuning of phase switches timing

• Show control of ramp to the desired degree (limited by number of free parameters)

• Eventually test acceleration with probe beam (short pulse, scan method)

• Initial tests, end 2011• Eventual

improvements/upgrades, shut down 2011/2012

• Full test, including probe beam acceleration, mid/end 2012

20122012

R. Corsini, CLIC Project Meeting, 9 Dec 2011Achievements – Two-Beam Acceleration

34

TD24TD24Two-Beam Acceleration demonstration in CTF3 Two-Beam Test Stand

Drive beam OFF

Drive beam ON

Maximum probe beam acceleration measured: 31 MeV

Corresponding to a gradient of 145 MV/m

Maximum probe beam acceleration measured: 31 MeV

Corresponding to a gradient of 145 MV/m


kick angle = 400 µradkick angle = 340 µrad

Measured on OTR screen CA.MTV0790 (~4.9 m from the accelerating structure).

Andrea Palaia, Wilfrid Farabolini, Javier BarrancoBreak-down kicks

Achievements – Two-Beam Acceleration


Andrea Palaia

Break-down kicks,distribution

R. Corsini, CLIC Project Meeting, 9 Dec 2011Achievements – Accelerating Structures

37

• Continue conditioning/BDR measurements of TD24 in the shadow of other experiments

• Profit to improve power production stability/availability/rep rate

• Continue BD kick measurements

• Install couple of new structures, TD24 with wake-field monitors in winter shut-down 2011-2012

• First module should go in during winter shut-down 2012-2013

R. Corsini, CLIC Project Meeting, 9 Dec 2011Achievements – Accelerating Structures

38

New Data

Alexei DubrowskiWilfrid Farabolini


Bunch length control < 1 mm rms (end of linac)

Full beam loading (95% transfer) high current acceleration (up to 5 A)

Ring isochronicity ap < 10-4

Sub-Harmonic bunching with fast (< 6ns) 180 phase switch(8.5% satellites)

Control of ring length to better than 0.5 mm

Factor 2 combination in Delay Loop (from 3.5 to 7 A)

Bunch train recombination factor 4 in Combiner Ring (from 3 to 12 A)

Beam current stability ~ 0.1 % end-of-linac,~ 0.2 % combiner ring

Transverse rms emittance 100 p mm mrad (end of linac)

Bunch train recombination 2 x 4 in DL and CR (from 3.5 to 28 A)

Transverse rms emittance < 150 p mm mrad (combined beam)

Bunch length control < 1 mm rms (combined beam)

Beam current stability ~ 0.2 % for fully combined beam

CTF3 Achievements – What is still missing for feasibility – Drive Beam Generation

~ 0.05 % end-of-linac !

39

CTF3 Achievements – Drive Beam

~ 0.1 % factor 4~ 0.1% factor 2 after DL

~ 1 %


Beam-powered test of a PETS with external recirculation to 170 MW, <200 ns - ~10 A beam currentPower & drive beam energy loss measurements.

CTF3 Achievements – What is still missing for feasibility – TBL / TBTS / CALIFES

Beam-powered test of a PETS to nominal parameters (135 MW, 240 ns) with external recirculation (10 A) and without (20 A) – including probe beamImproved power & drive beam energy loss measurements

Break-down kick measurements

PETS On-off mechanism demonstration

Drive beam phase

8 (12 > 16) PETS + spectrometer installed to verify transport of a 28 A beam with up to 30% of energy extracted.

Probe beam acceleration to 100 MV/m. (up to 145 MV/m measured)

40

CTF3 Achievements – Two-Beam issues

9 PETS20 A beam25% deceleration

R. Corsini, CLIC Project Meeting, 9 Dec 2011Outlook

Drive Beam:

- Flatness, RF pulse shape control (main beam loading), - Charge & energy stability)- Emittance- Bunch length- Phase monitor qualification, DB phase stability studies

TBL:

- 12 PETS, > 20 A deceleration- Dispersion free steering, optics studies- Possibly, new PETS prototype for TBL+ (input coupler, mini-tank)

TBTS:

- PETS on/off final test, BDR control- New structures, conditioning & BDR measurements- Wakefield monitors tests- BD studies (flashbox)- Continuation of BD kicks measurements


Thanks again


Breakdown rate at 100 MV/m (unloaded) accelerating gradient and scaled to 180 ns pulse length

Measurements scaled according to

SLAC Tests

SLAC Tests

CERN built,old procedure

CERN built,old procedure

UndampedUndamped

DampedDamped

1st generation, moderate efficiency

1st generation, moderate efficiency

2nd generation,high efficiency

2nd generation,high efficiency

43

Accelerating Structure - Experimental results

CTF3 Two-Beam

CTF3 Two-Beam

KEK Tests

KEK Tests

R. Corsini, CLIC Project Meeting, 9 Dec 2011Beam Recombination

Factor 8Factor 8

Factor 4Factor 4

R. Corsini, CLIC Project Meeting, 9 Dec 2011Gun current Correction

Alexandra Andersson


Gun adjusted, no switchesGun adjusted, no switches

Switches introducedSwitches introducedSwitches, gun re-adjustedSwitches, gun re-adjusted

Compensation of phase switches

Alexandra Andersson, Frank Tecker, Piotr Skowronski


No switchesNo switches

SwitchesSwitches

Compensation of phase switches

Frank Tecker, Piotr Skowronski

R. Corsini, CLIC Project Meeting, 9 Dec 2011Optics studies, orbit correction

Ben Constance

Guido Sterbini, Ben Constance

Model checks in CRModel checks in CR

Orbit correction in TL1 - CROrbit correction in TL1 - CR

R. Corsini, CLIC Project Meeting, 9 Dec 2011TBL with 9 PETS tanks

Steffen Doebert, Reidar Lillestol

R. Corsini, CLIC Project Meeting, 9 Dec 2011TBL with 9 PETS tanks

Reidar Lillestol

R. Corsini, CLIC Project Meeting, 9 Dec 2011TBTS first operation with Petsonov

PETS OnPETS On PETS OffPETS Off


R. Corsini, CLIC Project Meeting, 9 Dec 2011TBTS first operation with Petsonov


Petsonov used in recirculating mode

Petsonov used in recirculating mode

Conditioning - vacuumConditioning - vacuum


Reidar Lillestol

Emittance at TBL entry


CLIC RF Power Source Layout

Drive Beam Acceleratorefficient acceleration in fully loaded linac

Power Extraction

Drive Beam Decelerator Section (2 24 in total)

Combiner Ring 3

Combiner Ring 4pulse compression & frequency multiplication

pulse compression & frequency multiplication

Delay Loop 2gap creation, pulse compression & frequency multiplication

RF Transverse Deflectors

140 ms train length - 24 24 sub-pulses4.2 A - 2.4 GeV – 60 cm between bunches

240 ns

24 pulses – 101 A – 2.5 cm between bunches

240 ns5.8 ms

Drive beam time structure - initial Drive beam time structure - final

54

The CLIC RF Power Source Concept

R. Corsini, CLIC Project Meeting, 9 Dec 2011CLIC Test Facility (CTF3)

DRIVE BEAM LINAC

CLEXCLIC EXperimental Area

DELAY LOOP

COMBINERRING

CTF3 – Layout

10 m

4 A – 1.2 ms150 Mev

28 A – 140 ns150 Mev

Two-Beam Test Stand (TBTS)

Test Beam Line (TBL)

55

Scaled model of CLIC RF power source - built partly re-using existing infrastructure

• Made it affordable• Different parameters – in some cases issues more difficult than in CLIC

Scaled model of CLIC RF power source - built partly re-using existing infrastructure

• Made it affordable• Different parameters – in some cases issues more difficult than in CLIC


What do we learn in CTF3, relevant for the CLIC RF power source ?

System quantity/issue CTF3 CLIC

Injector/linac bunch charge 2-3 nC 7.7 nCcurrent 3.5 - 4.5 A 4.2 Apulse length 1.4 ms 140 ms

phase coding samefrequency 3 GHz 1 GHztransverse stability about the same - CTF3 ``too stable ´´

Delay loop/ring final current 30 A 110 Abeam energy 150 MeV 2.4 GeVcombination 2 - 4 2 - 3, 4CSR, wakes worse in CTF3 (lower energy)Deflector instability about the same

Power production (PETS) Aperture 23 mm 23 mmLength 1 m 23 cmPower > 135 MW 135 MWPulse length 140 ns (240 with recirculation) 240 ns

Decelerator Fractional loss 50-60 % 90%Final energy 70 MeV 240 MeVwakes, stability somehow ``masked´´ in CTF3beam envelope much larger in CTF3

In general, most of unwanted effects are equivalent or worse in CTF3 because of the low energy, however in CLIC the beam power is much larger (heating, activation, machine protection)Needed tolerances on the final drive beam parameters (phase, current, energy stability...) are more stringent in CLIC – some could be demonstrated in CTF3 as well

A non-exhaustive list easier more difficult

CLIC Test Facility (CTF3)

ctf3 measurements and plans r. corsini for the ctf3 team

Documents

clic project meeting

beam lines

beam stability

beam acceleration test

test beam line tbl

clic goal

mvm clic nominal gradient

nominal clic pulse length