Walter Wuensch CLIC project meeting, 31 March 2015 Accelerating structure program: design and testing

Walter WuenschCLIC project meeting, 31 March 2015

Accelerating structure program: design and testing


Our current prototype structure designs date back to 2007/2008. There have been many important developments since then, with a cumulative effect which motivates launching a new set of prototypes.• Highlight the developments and the logic for designing new CLIC

baseline structures.• Review other new structures in the pipeline; baseline

alternatives, other applications and structures built by collaborators.

• Update the high-gradient testing program

Introduction


High-gradient data and analysis


Progress in understanding and feedback on rf design


LHC results, energy staging and rebaselining

Most efficient structure is very similar to CLIC_G


ConsequencesWe are now launching a new series of prototype baseline CLIC accelerating structures for high-gradient testing:

CLIC-G* - Optimized 3 TeV structure, new cell shape, constant ΔT, optimized damping features. Higher performance.

CLIC-G*-with-SiC – Smaller overall transverse size, revised mechanical design of vacuum manifolds, new loads. Simpler, cheaper design.

Two more are being defined but we don’t yet have final decisions:

CLIC-380 – Features as above but for entry energy, lower gradient but same rf constraints. Understanding, publicity, first structure needed.

CLIC-ST – Strongly tapered design. Depends on results of beam-loading experiment. Complex to understand but significant potential performance increase.


Timescale

• CLIC-G* and CLIC-G*-with-SiC – 2nd half 2016• CLIC- 380 - End 2016, early 2017• CLIC-ST - Hmmm

Quantities need to be decided before procurement.

Parametersfixed rf design

mechanical design procurement assembly

12-18 months


• Structure in halves by SLAC. Potentially cheaper, hard materials, preconditioned surfaces possible.

• Choke-mode damping by Tsinghua. Potentially cheaper

• Four XFEL structures by SINAP. New application with large potential.

• High-gradient proton funded by KT. New application.

Additional new accelerating structures


• Two TD26CC built and tested by KEK. Still unbeaten production!• One TD26CC built by CIEMAT. Next step after PETS.• Two T24s built by PSI in their production run. Vacuum brazing alternative,

benchmark for their production line.• One T24 built by SINAP. Potentially leads to large X-band installation.• Whole structure in industry – Technical specifications are under preparation.

Industrialization, cost estimate.

New accelerating structures in the pipeline built by collaborators


A now a look at our testing program

• XBox-1 and 2 clear since they run. • Delivery, installation, commissioning and testing for XBox-3 is work in progress. Big

job.• Steadily increasing testing capacity should more or less coincide with the arrival of

all the new structures.

NCL. 27.03.2015A M J J A S O N D J F M A M J J A S O N D

NEXTEF

ASTA

TBTS Slot 1

Slot 2

Xbox1 Dogleg

CTF2

Xbox2 Slot 1

Xbox3_a Slot 1

Slot 2

Xbox3_b Slot 3

Slot 4

2015 2016

TD26_CC_SiC_3 TD26_CC_SiC_5

Crab cavityKl. Repair and

full power testTD26_CC_2

CFT3 winter shutdown

TD26_CC_SiC_3 TD26_CC_SiC_5

TD26_CC_SiC_4 TD26_CC_SiC_6 TD26_CC_SiC_4 TD26_CC_SiC_6

TD26_CC_1

T24_1

CLICG'

RF comp. T24_2

Commissioning

TD26_CC_3

Half_SLAC_1

TD24_R05_SiC_1

RF components PS1#1

TD24_R05_SiC_2

FEL SINAP

T24_3

New

bas

elin

e str

uctu

res


Shorter Term Priorities

• Repeat TD26CC - Consolidate (finish) CLIC baseline point. Validate compact coupler design.

• First TD24-SiC in low-breakdown rate regime. Complements SiC structures in module.

• Repeat T24 – We have not been able to reproduce KEK T24 result with CERN (beam-loading) or Tsinghua (first try) fabrication. • Questions our fabrication quality• Means relative performance of damped/undamped still an open

question• Reference for XFEL

• Waveguide components; rf valve, 3D printed components, controlled fabrication. For once test before installing… Will use Toshiba klystrons during installation/commissioning of XBox-3.


Test stands status overview

• XBox-1 – T24, beam loading experiment ongoing and will continue.

• XBox-2 – Finish crab cavity, TD26CC next.• XBox-3 – Under preparation. • NEXTEF – Finish Tsinghua-built T24. KEK-built TD24R05

next.• ASTA – Commissioning clone of our NI-based control

system. KEK/SLAC-built TD24R05 installed and ready to go.


Conclusions

• New CLIC baseline structures are being designed and should begin to be ready for test late next year.

• New structures are also in the pipeline• baseline alternatives• built by collaborators• other applications

• XBox-1, XBox-2 and NEXTEF running and producing important results. XBox-3 coming on line during this year. Even ASTA is about to start up.

• Fabrication developments, pulsed dc, single cells, fundamental high-gradient studies, alternative materials another day.


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Walter Wuensch CLIC project meeting, 31 March 2015 Accelerating structure program: design and testing