introduction to ctf3 g.geschonke cern / ps · 2008. 1. 15. · ctf3 is not a user facility...

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Introduction to CTF3 G.Geschonke CERN / PS

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Page 1: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Introduction to CTF3

G.Geschonke CERN / PS

Page 2: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Review the technical solutionsare they realistic ?

Give us technical adviceComment on alternatives

Guide our funding bodies: CERN Collaborations

CTF3 is only possible as International collaboration

INFN Frascati LAL Orsay Rutherford Appleton Laboratory SLACStrathclyde UniversityUppsala University

Aim of review:

Page 3: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

CTF3 is not a user facility

Experimental machine :

Demonstration of the RF power generation scheme for CLIC • Novel drive beam scheme in the two-beam scenario • This two-beam scheme is not limited to CLIC long RF pulse at low frequency ==> short RF pulse at high frequency with high power using an electron beam for energy storage

high efficiency

Demonstration of major CLIC Components

RF power source at 30 GHz with nominal CLIC parameters

Make use of already existing material:

LPI complex available since LEP shut-down: LEP injector Linac LIL and Electron-Positron Accumulator EPA

Building : Linac tunnel, space for rings, control room

Hardware: 3 GHz RF system: klystrons, modulators, accelerating sections

magnets, power supplies,control system

==> some technical choices are a consequence of existing equipment

Page 4: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

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CTF3 CLIC (3 TeV)Drive beam

Acceleration frequency MHz 2 998.55 937repetition rate Hz 5 100

energy MeV 150 1180Number of accelerating structures 16 + 2 182

average current after linac A 3.5 7.5Number of klystrons 10 182 x 2

Number of RF pulse compressors 9 0Beam pulse length Ps 1.4 92

Bunch spacing before compression cm 20 64Delay Loop length m 42 39

Combiner Ring length m 84 78Average beam current after

compressionA 35 240

Bunch spacing after compression cm 2 2Drive beam energy per pulse kJ 0.8 814

average beam power kW 4.1 81 000Main beam

Number of accelerating structures max 8 22 x 976RF Pulse length ns 140 130

Acceleration Frequency GHz 30 30Acceleration Gradient MV/m 150 150

CLIC - CTF3

Page 5: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

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“Phase-coding” of bunches

Page 6: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Bunch frequency multiplication - Combiner Ring injection

3rd turn

1st turn injection line

transverse deflector field

�o = 20 cm

localinner orbits

1st deflector 2nd deflector

septum2nd turn

5th turn�o/5 (2 cm)

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Page 7: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

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Generic layout of CTF3

Page 8: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

CTF3 layout - Nominal phase

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Page 9: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Main objectives and challenges

Delay loop, Combiner ring, bunch compressorinjection with RF deflectorisochronous latticeImpedancecoherent synchrotron radiationhandling of 35 A beam current

Drive beam production:3.5 A, Estimation: Stability of Voltage and beam current of 10-3 !satellite bunchesbunch phase coding

Thermionic injector wide bw 1.5 GHz klystron

Alternative: Laser gun

3 GHz RF:pulse compression, long flat-top

longer RF pulse, phase rampingNew BOC development

Drive beam accelerator:Near 100% beam loading high beam current in short bunchesbeam stability

strong damping of HOM , new RF structures

bunch length manipulation

Page 10: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

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Drive beam accelerating structure

TDS (Tapered Damped Structure)

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SI: A+3,10,4, B-5,CELL-6,15 A: 1.700E+01 MM, B: 3.703E+01 MM. FOR REF., E.J., JUNE 2000X COMPONENT OF WAKE POTENTIAL IN V [INDIRECT CALC.]

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High beam current => Beam induced modes have to be damped Prototype of TDS structure built, RF power testedNew structure type has been developed : (SICA = Slotted Iris Constant Aperture)

wake fields along structure with and without damping (SICA)

Page 11: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

CTF3 - Nominalphase

2005 - 2006

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Page 12: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

DiodeGunModulator

40 MW3 GHz

40 MW3 GHz

33 MW3 GHz

33 MW3 GHz

33 MW3 GHz

33 MW3 GHz

33 MW3 GHz

MDK 03

MDK 97

MDK 13

MDK 15

MDK 27

MDK 29

MDK 02

MDK 33

5 MeV 15 MeV 16MeV 16 MeV 16 MeV 16 MeV 16 MeV 16 MeV

MG00

G

MDK 01

SHB

PB1 PB2 B1 S1 S2A1 A2 A3 A4 A7 A8 A9 A10 A11 A12 A15 A16

1.5GHz0.5MWBW 150MHz

Splitter

40 MW3 GHz

X 5RING

X 2 RING

RFDEFL

RFDEFL

septum MDK 35

1.5GHz20 MW1.6 uS

FROMDBA

Beam Energy~150 MeV

RFDEFL

DBA energy is 150 MeV, 2.33 nC per bunch (3.5A),2000 bunches, and 1.4us pulses driving 1.22m long structures.RF peak power at each DBA structure input ~30 MW.The LIPS/BOC gain ~ 2.0. Average waveguide length is 20m giving about a 10% loss from LIPS output to the input of the accelerating sections.

33 MW3 GHz

MDK 25

16 MeV

A5 A6

MDK 98

30 MW3 GHz

Test MDK & Probe beam RF

10MW

MDK 31

33 MW3 GHz

16 MeV

A13 A14

Phaseshifter

Attenuator

Attenuator-

Splitter Splitter Splitter Splitter Splitter Splitter Splitter Splitter Splitter

Splitter

Splitter

RF power plant 3 GHz and 1.5 GHz

Page 13: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Radiation shielding Beam power 5 kW !

shielding assumes :permanent beam loss of only 5% (250 W)beam loss monitors in interlock chain shut-off beam

additional shielding required:

some outside walls

between accelerator tunnel and klystron gallery above up to 20 cm of iron

above EPA:additional 90 cm concrete

make room for DLnew CLEX building

Major building modifications

Other building modifications:

Page 14: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Construction in phases

:Preliminary phase2001 / 2002

Initial phase:New injector,

LPI + modified EPAnew e-gunonly 8 accelerating sectionsEPA ring 17 mm shortertransfer lines and EPA isochronous

demonstrate bunch recombination by factor 3-5 using 2 RF deflectors

limited beam current

Page 15: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Initial phase2003 / 2004

new injector (no Sub-harmonic bunchers ...)new accelerating structures for DBA30 GHz test station after linac

transfer linescombiner ring

Injector DBACR

30 GHz test station

combination tests can be done at reduced bunch charge

Page 16: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel
Page 17: Introduction to CTF3 G.Geschonke CERN / PS · 2008. 1. 15. · CTF3 is not a user facility Experimental machine : Demonstration of the RF power generation scheme for CLIC • Novel

Collaborations

SLAC:triode assemblyInjector optics and layout

LAL:gun, HV deckpre-bunchersCLIO-type gun for prel. phases already delivered

INFN Frascati:transfer lines, bunch lengthening chicaneDelay Loop layout and hardwareCombiner Ring layout and hardwareRF deflectorsFast kickersParticipate in commissioning and exploitation

RAL and Strathclyde University:Laser for Photo-Injector option

Uppsala University:mm wave detector for beam diagnosticsparticipation in commissioning