Development of Dielectric PETS

Chunguang Jing and Wei Gai

ANL and Euclid

CLIC workshop 2013

Dielectric-lined Waveguide to Slow the Wave

Electric Field Vectors (TM01)

• Advantages: simplicity of fabrication

low surface field enhancement

easy deflecting mode damping

• Challenges: Multipactor

Er/Ez=a/

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Using CLIC Beam: σz=1mm, Q=8.4nC, Tb=83ps

Freq 11.994GHz

Effective Length 23cm

Beam channel 23mm

Dielectric wall thickness 2.582mm

Dielectric const. 3.75(Quartz)

Q 7318

R/Q 2.171k/m

Vg 0.4846c

Peak surface Gradient Ell=12.65MV/m; E=18.28MV/m

Steady Power 142MW

Dielectric PETS Parameters

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Engineering Design RF output coupler

Impedance matching section

Dielectric loaded waveguide

Transverse mode damping

Quartz tube

metalization

SiC tube

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Current Status

• quartz tube and damping features are in hand.• copper parts and coupler are under fabrication.• final assembly will be done by the middle of Feb. 2013.

Quartz tube

Brazed copper ring

w/ 3 section of damper

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11.4GHz version is under high power rf test at SLAC

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Setup at SLAC ASTA facility

Testing data on 1/25/2013

Power: 16MW

Vacuum deceases as power stay at a certain level for a while.

Test plan: 50ns to full power first; then gradually increases the pulse length to 200ns.

Torr

Testing data on 1/28/2013

Power: 24MW

Vacuum deceases as power stay at a certain level for a while.

Torr

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we would like to get an opportunity to conduct the beam experiment of 12GHz Dielectric PETS at CLIC.

Thank you!

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Introduction--- AWA Facility in 2013: 75 MeV Drive Beam+ 15MeV witness beamBasic parameters for the drive beam:• 1.3GHz Photogun w/ CsTe cathode• 75 MeV, 1 – 100 nC (reached 150 nC)• 1~2.5 mm bunch length (a bunch compressor is

planned )• Normalized emittance < 200 mm mrad (at 100 nC)• Bunch train operation: 32 X 30nC or 10 X 100nC• Beam power: 3GW or 10GW

Experiments forecast in 5 years:• High power rf generation: 0.1~1GW, ~20ns duration, frequency covers cm to mm wave.• Two beam acceleration: >200MeV/m energy gain (short rf pulse, ~20ns).• Collinear wakefield acceleration: >300MeV/m energy gain.• Bunch shaping to improve efficiency for collinear wakefield acceleration

New drive gun w/ CsTe cathode

Thanks to DoE for $2M+ upgrade fund:• 2 new klystrons • 6 linac tanks• RF distribution and Control systems upgrade• Laser upgrade

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Klystrons Stations 6 Linacs are ready for use New KrF UV amplifier

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Thanks to ANL management for $2M+ construction fund:• new annex building• new SF6 recovery system• new cooling water station• new 1MW power transformer

Bunker Interior New annex building Roof of the new bunker

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AWA Facility update: