• CTF3 & CLIC Parameters

• Instrumentation already developed

• What will be done in the CLEX

CTF3 versus CLICCTF3 versus CLIC

T. LefevreInstrumentation Working Instrumentation Working GroupGroupCLIC 07CLIC 07

Electron beam manipulation

Long RF PulsesP0 , n0 , 0

800 Klystrons

low frequencyhigh efficiency

Power stored inelectron beam

Short RF PulsesPA = P0 N1

A = t0 / N2 A = 0 N3

144000 Accelerating Structures

high frequency high gradient

Power extracted from beamin resonant structures

The CLIC RF power source can be described as a “black box”, combining very long RF pulses, and transforming them in many short pulses, with higher power and with higher frequency

What does the RF Power Source do ?

CLIC Drive BeamCLIC Drive Beam T. Lefevre

CLIC 07CLIC 07

CLIC Drive BeamCLIC Drive Beam

Drive Beam Acceleratorefficient acceleration in fully loaded linac

140 s total length - 24 24 sub-pulses - 4.2 A2.4 GeV - 60 cm between bunches

240 ns

Drive beam time structure - initial

24 pulses – 100 A – 2.5 cm between bunches

240 ns5.8 s

Drive beam time structure - final

Power Extraction

Drive Beam Decelerator Sector (24 in total)

Combiner ring 3

Combiner ring 4pulse compression & frequency multiplication

pulse compression & frequency multiplication

Delay loop 2gap creation, pulse compression & frequency multiplication

Transverse RF Deflectors

RF Power Source Layout

T. Lefevre

CLIC 07CLIC 07

Covered by EUROTeV

Covered by CTF3

• R2.1: Developments of structures with hard-breaking materials (W, Mo…)

• R2.2: Validation of stability and losses of DB decelerator; Design of machine protection system

• R2.3: Test of relevant linac sub-unit with beam

• R2.4: Validation of drive beam 40 MW, 937 MHz Multi-Beam Klystron with long RF pulse

• R2.5: Effects of coherent synchrotron radiation in bunch compressors

• R2.6: Design of an extraction line for 3 TeV c.m.

• R1.1: Test of damped accelerating structure at design gradient and pulse length

• R1.2: Validation of drive beam generation scheme with fully loaded linac operation

• R1.3: Design and test of damped ON/OFF power extraction structure

R1: Feasibility

R2: Design finalization

* Feasibility study done – need development by industry. N.B.: Drive beam acc. structure parameters can be adapted to other klystron power levels

*

The CLIC Technology-related key issues as pointed out by ILC-TRC 2003

T. Lefevre

CLIC 07CLIC 07MotivationMotivation

Motivation and goals of CTF3 collaboration

Build a small-scale version of the CLIC RF power source, in order to demonstrate:

full beam-loading accelerator operation electron beam pulse compression and frequency multiplication using RF deflectors

Provide the RF power to test the CLIC accelerating structures and components

CTF3 is being built at CERN by a collaboration modeled on the large physics experiments

23 institutes from 12 countries

Chairman of collaboration Board: M. Calvetti (INFN-LNF)Spokesperson: G. Geschonke (CERN)

Will be largest LC test facility constructed M. Huening, A. Mosnier, V. Shiltsev & T. RaubenheimerCLIC Advisory Committee Report

T. Lefevre

CLIC 07CLIC 07MotivationMotivation

CTF3 Evolution

Drive Beam Injector (2003)

Drive Beam Accelerator

(2004)

Delay Loop (2005)

Combiner Ring(2006-07)

TL2(end 2007)

CLEX(2007-08)

CTF3 ComplexCTF3 Complex

CLIC Test Facility 3 to show the feasibility of the CLIC RF Source & Two Beam Acceleration for a multi-TeV e+-e- collider

16 Institutes

T. Lefevre

CLIC 07CLIC 07

CTF3 PrincipleCTF3 Principle

42m Delay loop x2 (8-10ps bunch length)

84m Combiner ring (x4)

(8-10ps bunch length)

Linac2-4ps bunch length

CLEX

(1ps bunch length)

RF deflectors for injections in the rings

Bunch frequency multiplication by a factor 8 : from 1.5 to 12GHz

1.56 s train length – 4A, 150MeV20 cm between bunches

140 ns

140ns pulse - 30A, 150MeV 2.5cm between bunches

140 ns

Initial time structure Final time structure

T. Lefevre

CLIC 07CLIC 07

CLIC Drive Beam / CTF3CLIC Drive Beam / CTF3

Beamparameters

DB GenerationComplex

DB Decelerator(24 units)

CTF3Linac

CTF3CLEX

Electrons energy 2.38 GeV 2.38 0.238 GeV

150MeV 150MeV

Beam current /charge

4.2A / 587C 101A / 24.4C 4A / 1.6C 30A

Total Beam Energy 1.397MJ 58 5.8kJ 240J 240J

Bunch length 6-13ps 3.3ps 2-10ps 1ps

Minimum beam size 50m 50m 50m

Charge density 3.7 109 nC/cm2 1.5 108 nC/cm2 1.1 107 nC/cm2

The thermal limit for ‘best’ material (C, Be, SiC) is ~ 1 106 nC/cm2

• Control of beam loss to prevent beam induced damage (10-4)

• Use of non-intercepting / non degradable beam diagnostic

• Strong scaling factor from CTF3 to CLIC

T. Lefevre

CLIC 07CLIC 07

Beam Parameters

CTF3 detectorType

CTF3 detectorPerformances

Intensity Wall Current Monitor Dedicated talk

Position x,y Inductive Pick-up Dedicated talk

Energy spread E/E

Bunch length z RF pick-up, RF deflector, Streak camera Talk on RF pick-up

Beam size & emittance

Beam loss Ionization chamber, ACEM, Cherenkov monitor

Dedicated talk

Bunch frequency multiplication

RF techniques Dedicated talk

Phase stability RF techniques Dedicated talk

Measurement @ CTF3Measurement @ CTF3 T. Lefevre

CLIC 07CLIC 07

What is presented in this talk

High efficiency acceleration schemeHigh efficiency acceleration scheme

Full beam-loading acceleration in TW sections

RF in

“short” structure - low Ohmic losses

RF to load

most of RF power (≥ 95%) to the beam

High currentbeam

No

No beam

T. Lefevre

CLIC 07CLIC 07

Lstruct

loaded

Gacc

s

unloaded

E0

t

tfill

steady state E0 /2

Ebeam

400300-5

0

5

time (nsec)

P/P (%

)

P1050Central

=107.5MeV/c

-50

5

600

700

800

900-10-5

05

10-1

-0.5 0

0.5 1

P/P (%

)

Ppeak

=108.5 MeV/c,

P

FWHH

=11.68%

600700

800900

0 1 2 3 4 5

IBeam

(A)

time (nsec)

600700

800900

108

110

112

Ppeak

(MeV/c)

time (nsec)

600700

800900

1 2 3

PFWHH

(%)

200100

Transient

Steady stateP/P

(%

)

Time (ns)

Time resolved beam energy spectrum measurement in CTF3

RF Power Source “building blocks”

Full beam-loading acceleration in TW sections

Time resolved spectrometry @ CTF3Time resolved spectrometry @ CTF3 T. Lefevre

CLIC 07CLIC 07

BendingMagnet

e-

• 24 Tungsten plates (2mm thick) spaced by ~ 1mm• Connected to 50 Ω to the ground

• Slit dump ( 2mm slit and a dump in steel)

Segmented DumpOr Slit Dump

OTR Screen&

Segmented PMT

- 32 channels PMT (Hamamatsu)- 2mm spatial resolution - 36dB, 100MHz amplifier in the klystron gallery

Time resolved spectrometry @ CTF3Time resolved spectrometry @ CTF3 T. Lefevre

CLIC 07CLIC 07

• Problem with synchrotron light in the bending magnet

@ 100MeV: ph/e- 4.10-3(SR) versus 9.10-3 (OTR)

• Parabolic OTR screen in order to optimize the collection of the light

OTR & Segmented PhotomultiplierOTR & Segmented Photomultiplier T. Lefevre

CLIC 07CLIC 07

Implement a carbon foilas SR light shielding

•Collimator in Steel• Mounted on the beam tube• 32 vertical slits 400microns thick• Water cooled

electrons

Segmented DUMP • 32 Tungsten plates (2mm thick) spaced by ~ 1mm• Insulator in Alumina (rad-hard)• New Ceramic electronic card connected to the dump segments• Alignment balls has been added• Connected to 50Ω to ground (increasing signal to noise ratio)

Results

Fluka simulationsof energy deposition

• 20MeV Electrons• Beam size in x : 3mm sigma

Segmented DumpSegmented Dump T. Lefevre

CLIC 07CLIC 07

Camera

OTR Light

ElectronsOTR screen

Camera

lenses

OTR ScreensOTR Screens T. Lefevre

CLIC 07CLIC 07

Created when charged particles pass through the interface between two materials with different permittivity

Angular distribution of OTRQuad Scan in X Quad Scan in Y

• Thin Al foil is fragile • Using 200m Si wafer with a very good surface quality• Adding an Aluminum coating to provide an excellent reflectivity coefficient (90%)

High reflectivity screens for low charge beam

• 200m thick Polished CVD SiC•Non homogeneous surface of C

Thermal resistant material for high charge beam

30% Reflectivity coefficient

OTR Screens limitations OTR Screens limitations T. Lefevre

CLIC 07CLIC 07

Use Synchrotron light produced in the rings or OTR/Cherenkov screens in a linac

‘Streak cameras uses a time dependent deflecting electric field to convert time information in spatial information on an intensified CCD’

• 200fs time resolution at best using state of the art Cameras : FESCA 200• Limitations :(i) Initial velocity distribution of photoelectrons : narrow bandwidth optical filter(ii) Spatial spread due to the size of the slit(iii) Dispersion in the optics

- Streak Camera -

TUPB29, TUPC11, WEPB05, WEPB12, WEPB20

Focusing element

Bunch length monitoring Bunch length monitoring T. Lefevre

CLIC 07CLIC 07

‘ CTF3 Complex’

SR@ Delay Loop

= 8.9ps (2.7 mm)“Nominal” chicane - R56 = 0.45

OTR@ linac

= 4.5ps (1.4 mm)

Sweep speed of 10ps/mm

Bunch length can be manipulated at the end of the linac using a magnetic chicane 2 Optical lines to the streak camera

•Synchrotron Radiation in the Delay Loop•OTR in the linac at the exit of the Delay Loop

Bunch length monitoring Bunch length monitoring T. Lefevre

CLIC 07CLIC 07

Old (1960-70’s) idea to use RF deflector as a bunch length monitor

• The RF Deflector can be seen as a relativistic streak tube.• The time varying deflecting field of the cavity transforms the time information into a spatial information• The bunch length is then deduced measuring the beam size at a downstream position using a screen (or Laser Wire Sanner)

y0

y

Deflecting mode TM11

Betatron phase advance(cavity-profile monitor)

Beta function at cavity and profile monitor

Beam energy

RF deflector phase

RF deflectorwavelength

Deflecting Voltage

Bunch length

Resolution will depend on : (sub-100fs)• Screen spatial resolution• Deflecting power• Beam optic between the deflector and screen

MOO2A02, TUPB13, TUPB3 & WEO2A03 by A. Cianchi,

Bunch length monitoring Bunch length monitoring T. Lefevre

CLIC 07CLIC 07

3GHz RFDeflector

Camera

OTR Light

Bunch length 0.5 mm (1.2ps)

Bunch length 2.5 mm (6ps)

30o offcrest on last klystron

Bunch length monitoring Bunch length monitoring T. Lefevre

CLIC 07CLIC 07

How can we make profile monitor for the Drive Beam Linac

• No non-intercepting transverse profile monitor available for low energy electron beams in a linac

• Degradable profile monitor• ‘Kalachnikov’ : bullet scanner

C. Dimopoulou, PS/BD note 99-12

• Neutral beam scanner : Gas jet

m size bullet

e

Beam lossdetector

• Any new idea highly welcome…

No conclusionNo conclusion T. Lefevre

CLIC 07CLIC 07

Back-up SlidesBack-up Slides T. Lefevre

CLIC 07CLIC 07

P0 , 0

P0 , 0

Beam combination/separation

by transverse RF deflectors

RF Deflector,

Deflecting

Field

Transverse

02 P

0 , 2

0

RF Power Source “building blocks”

RF DeflectorRF Deflector T. Lefevre

CLIC 07CLIC 07

Beam combination/separation

by transverse RF deflectors

RF Deflector,

Deflecting

Field

Transverse

0

RF Power Source “building blocks”

P0 , 0

P0 / 2 , 0 / 2

P0 / 2 , 0 / 2

CLIC Drive BeamCLIC Drive Beam T. Lefevre

CLIC 07CLIC 07

Delay LoopDelay Loop

odd buckets

even buckets Delay

Loop

RF deflector

Combination scheme

Gap creation & first multiplication 2

Ldelay = n 0 = c Tsub-pulsePhase coding

180 phase switch

Acceleration 0

Deflection 0 / 2

Sub-Harmonic Bunching 0 / 2

How to “code” the sub-pulses

T. Lefevre

CLIC 07CLIC 07

Sub-harmonic bunching systemSub-harmonic bunching system

666 ps

1 8

Fast phase switch from SHB system (CTF3)

8.5 · 666 ps = 5.7 ns

satellite

3 TW Sub-harmonic bunchers,each fed by a wide-band TWT

Streak camera – 500 ps/mm

main

T. Lefevre

CLIC 07CLIC 07

0 500 1000 1500 2000 2500

6

4

2

0

t [ns]

I [A

]

1

1

2

2

3

3

Beam recombination in the Delay Loop (factor 2)

Delay Loop @ CTF3Delay Loop @ CTF3 T. Lefevre

CLIC 07CLIC 07

CTF3 bunch train combinationCTF3 bunch train combination

Phase coding in thesub-harmonic bunching system

Bunch frequency multiplication in delay loop

0 500 1000 1500 2000 25000

1000

2000

3000

4000

Lig

ht I

nten

sity

(a.

u.)

Time (ps)

0 500 1000 1500 2000 25000

500

1000

1500

2000

Lig

ht I

nten

sity

(a.

u.)

Time (ps)

Sweep speed 250ps/mm

SR light in the Delay Loop OTR light after recombination

T. Lefevre

CLIC 07CLIC 07

RF injection in combiner ring (factor 4 for simplicity)

3rd

o/4

4rd

2nd

Cring = (n + ¼) injection line

septum

localinner orbits

1st deflector 2nd deflector

1st turn

o RF deflector field

Frequency multiplication - Combiner RingFrequency multiplication - Combiner RingT. Lefevre

CLIC 07CLIC 07

2nd 3rd 4th1st turn

Final pulse train

N/4 pulses

Cring = c t = c 2 Tsub-pulse

pulse train from DL

N pulsest = 2 Tsub-pulse

Tsub-pulse

Frequency multiplication - Combiner RingFrequency multiplication - Combiner RingT. Lefevre

CLIC 07CLIC 07

333 ps

t

x

83 ps

Bunch combination (factor 4)2003 CTF3 Preliminary Phase results

Combiner ring bunch manipulationCombiner ring bunch manipulation T. Lefevre

CLIC 07CLIC 07

Bunch train combinationBunch train combination

Better RF combination• 7.5GHz

• 9GHz

t (ns)

0 500 10000

500

Lig

ht

Inte

nsity (

a.u

.)

Time (ps)

Wiggler on

0 500 10000

250

500

750

1000

Lig

ht

Inte

nsity (

a.u

.)

Time (ps)

Wiggler off

Bunch from the linac

Bunches fromthe DL

Bunches from the DL later by 12ps (3.6mm)

333 ps

OTR light and sweep speed 100ps/mm

‘ Adjust the delay loop length with a magnetic wiggler’

T. Lefevre

CLIC 07CLIC 07

Stretching in the Frascati Chicane Stretching in the Frascati Chicane T. Lefevre

CLIC 07CLIC 07

- Calibration of RF Deflector -

Make a power scan at zero crossing and (zero crossing – 180o) to check if there is no perturbation from linac wakefields

RF Phase (o)

Bea

m P

ositi

on (

mm

)

Use a Beam Position Monitor close to the Profile monitor to calibrate the deflection angleR34 = transfer Matrix element from cavity to the BPM

Bunch length monitoring Bunch length monitoring T. Lefevre

CLIC 07CLIC 07

- Bunch Length Measurement with the 1.5GHz RF Deflector of the Delay Loop -

OTR screen

• Maximum power of 20MW• 5degrees @1.5GHz = 9.25ps (4mm)

noRF = 0.35mm0Xing = 2.9mm (6.7ps)

Bunch length monitoring Bunch length monitoring

With this setting, the resolution is better than 1psMore tests must be done to check where the limits are

RF deflector offRF deflector on : 0 Xing

T. Lefevre

CLIC 07CLIC 07

• Measure the beam image current on the beam pipe using 8 electrodes• Electrodes are combined in pairs so that each transformer sees half of the load• Frequency low cut-offs are limited by connection parasitic resistances and primary electrode inductance

Design by Marek Gasior : CERN-AB-2003-063

Inductive Pick-up @ CTF3

Beam Position monitorBeam Position monitor

Inductive Pick-up @ CTF3

T. Lefevre

CLIC 07CLIC 07

Inductive Pick-up @ CTF3

• Resolution already I/I = 10-3

• For CLIC Drive Beam (100s pulse duration) need to lower the low frequency cut off

Beam Position monitorBeam Position monitor T. Lefevre

CLIC 07CLIC 07

>15 BPMs already installed in CTF3

Inductive Pick-up @ CTF3

Beam Position monitorBeam Position monitor T. Lefevre

CLIC 07CLIC 07

DiagnosticsBeam position

Test in CTF3 latethis year

L Soby – I. Podadera

High precision position High precision position measurementmeasurement

T. Lefevre

CLIC 07CLIC 07

Machine protection system @ CTF3

• Compare signals from consecutive Wall Current Monitors• If losses is detected, the electron gun is switched off• Time response dominated by cable length (>311ns)

D. Belohrad, Dipac Conference, Lyon, p.255, (2005) P. Odier, CERN-AB-2003-069

WCM

For CLIC DB the system will have to rely on Beam Loss Monitors

Manipulating high beam chargeManipulating high beam charge T. Lefevre

CLIC 07CLIC 07

L Soby – A. D‘Elia

DiagnosticsWall Current Monitor

High Bandwidth Wall Current High Bandwidth Wall Current MonitorMonitor

T. Lefevre

CLIC 07CLIC 07

Controller

• Single shot device

• +/- 50MHz bandwidth (react fast)

• 10fs resolution for phase measurement (0.1o @ 30GHz)

• +/- 5degrees range

• 6dB amplitude range

Drive Beam Longitudinal stability

Possible candidates for Tuners- RF deflectors in a dispersive and anisochronous area- Accelerating structures and chicane

• Use RF pick-up (30GHz) to measure the Drive Beam phase at 2 locations (≠ longitudinal dispersion) • Use tuners to correct the phase error

Layout of Phase feedback

Beam Phase monitorBeam Phase monitor T. Lefevre

CLIC 07CLIC 07

F. Stulle -PSI

Main/Drive Beam Phase stability

4% luminosity reduction = 0.225o

z = 6 m

Beam Phase monitorBeam Phase monitor T. Lefevre

CLIC 07CLIC 07

Femtosecond Phase detection

By J. Sladen and A. Andersson

• Mixing the 30GHz signal from the beam down to 750MHz• Measure the 750MHz signal Phase and Amplitude

• Goal to find a phase detector@750MHz with noise below 0.03o

• Phase detector can be multipliers or mixers

Beam Phase monitorBeam Phase monitor T. Lefevre

CLIC 07CLIC 07

DiagnosticsPhase measurement

• Phase accuracy: 0.1º

• Amplitude range: ~6dB

• Bandwidth: 50MHz, system investigated up to 250MHz

J. Sladen, A. Andersson

Beam Phase monitorBeam Phase monitor T. Lefevre

CLIC 07CLIC 07

CLic Experimental Areas (CLEX)CLic Experimental Areas (CLEX)

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

DF

F

D F DDUMPD F D

F

FD

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

DUMP

DUMP 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 m8 m

2m2m

D FFFDD

DF

FDD

FF

FF

D F DD F DDUMPD F DD F D

F

FD

F

FD

F

FD

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

DUMP

DUMP 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

T. Lefevre

CLIC 07CLIC 07