double quarter wave crab cavity helium vessel

HiLumi-LHC/LARP Crab Cavity System External Review – May 5-6 2014

Work partly supported by the EU FP7 HiLumi LHC grant agreement No. 284404 and by the US DOE through Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US LHC Accelerator Research Program (LARP). This research used resources of the National Energy Research Scientific Computing Center, which is supported by the US DOE under contract No. DE-AC02-

05CH11231.

Double Quarter Wave Crab CavityHelium Vessel

Silvia Verdú-Andréson behalf of the DQWCC team

May 5, 2014

http://www.uslarp.org/


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Outline• Conceptual design of the helium vessel and tuning system for the SPS

DQWCC– Overview: dimensions, weight, He volume– Cavity stiffening, pre-tuning and tuning systems – Helium vessel and tuning system: assembly sequence, connections and

interfaces, materials and joints

• Engineering studies– Pre-tuning and tuning range– Mechanical stresses– Thermal loads

• Summary



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• PoP helium vessel to introduce smoothly the conceptual design



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Cryo jumper

Tuner +

stiffening

Adjacent beam pipe through the vessel

beam

FPC

HOM

HOM

Helium vessel - concept

• Titanium and Niobium similar thermal expansion coefficient rigid connections for all ports• Piezo outside vessel larger tuning

range• Prep rings for eventual disassembly• All liquid helium – vacuum interfaces

welded for best vacuum tightness• Clearance to access to ports

PUPU

Ribs for additional stiffening

Can CERN provide drawing of tuning system with piezo part?



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Pre-tuning and tuning systems

Combined function: tuning + stiffening

H-field

Tuning by actuation on the central plates

E-field

Silvia: PoP SPS



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Nicer cross-section to show pre-tuning with bolts to be fixed onto helium vessel top plate??

Pre-tuning system

pre-tuning

• Pre-tuning ~ 1.6 MHz/mm(during assembly of cavity-vessel)for machining tolerances

Put Qiong’s table with machining tolerances



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Tuning system

Symmetric actuation onto both

central plates

Can CERN provide drawing with piezo location???

tuning

• Tuning(after installation) push-pull ~ 1.6 MHz/mm(during operation) piezo ~ 30 mmfor Lorentz detuning and microphonics



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Lorentz detuning

Lorentz detuning: 0.17 Hz/ (10J) – best case scenario

E-field H-field

Fixed all ports and central plates (best case scenario)

𝑃=14 (−𝜀0|�⃗�|2+𝜇0|⃗𝐻|2)



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Combined function: tuning + stiffening

on central plates

Stiffening during cooling down and pressure changes

All port connections are rigid but PU

Stiffening for cavity and helium vessel

Ribs Any additional stiffening for the cavity????



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Helium vessel - dimensions

660mm

470mm

390m

m

He capacity: ??Weight: ??

Integration into cryomodule



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Cavity assembly1



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Cavity assembly1 316LN SS

DN63CFFlanges for FPC and BP; others are NbTi

SS flange, Nb tube, Ti ring/adaptor

Ti

brazedwelded

HOM: NbTi flange welded to Ti adaptor and Nb tube



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Tuning system assembly1 2

Ti rod

brazedwelded



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Tuning system assembly1 2

3Ti

housing

brazedwelded



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1

2

3

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Helium vessel assembly

brazedwelded

Ti prep ring

Ti prep ring

Ti vessel

Grade 2 titanium.

Integrated section of adjacent beam pipe in which material??

Cryo tube in SS brazed to prep tube in Ti. SS – H ; Ti-V



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Helium – vacuum interfaces

• All liquid helium – vacuum interfaces welded

No flow! Find another word



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Cooling and heat-stationing

Helium chamberfor HOM filter

Heat-stationing for tuning frame

Heat-stationing for tuning tube

He



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Heat loads – tuning system • Picture with temperature to show gradients• Picture of simulation result

CERN: heat load for tuning system



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Total heat load

To be updated: Skaritka



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Mechanical stresses1. Helium pressure2. 300 K 2K3. Actuation of tuning system



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Helium



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Mechanical stresses due to helium pressure

• Constrains (fixed boundaries, etc)• Load(s) and number of cycles (if applies)• Max. stress allowed• Picture of mesh• Picture of initial constrains and loads• Picture of stress value and deformation arrows• Design elements incorporated to counter-act load effects• Young modulus and Poisson’s ratio



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Mechanical stresses due to thermal contraction (300K 2K)

• Constrains (fixed boundaries, etc)• Load(s) and number of cycles (if applies)• Max. stress allowed• Picture of mesh • Picture of initial constrains and loads• Picture of stress value and deformation arrows• Design elements incorporated to counter-act load effects• Thermal expansion coefficient for Niobium and Titanium,

Young modulus and Poisson’s ratio



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Mechanical stresses due to tuning system actuation

• Constrains (fixed boundaries, etc)• Load(s) and number of cycles (if applies)• Max. stress allowed• Picture of initial constrains and loads• Picture of mesh• Picture of stress value and deformation arrows• Design elements incorporated to counter-act load effects• Young modulus and Poisson’s ratio



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Tomorrow’s presentation by John Skaritka



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Summary• Compact vessel for compact cavity• Dedicated vessel design to:

– minimize liquid helium leak chances (all helium-vacuum interfaces welded)

– ease assembly, particularly the access to cavity ports– ease disassembly (prep rings)

• Robust vessel design?? • Appropriate stiffening of the cavity provided by rigid connection

of cavity ports to vessel and tuning system• Manifold tuning : pre-tuning + push-pull + piezo• Optimized design for reduced heat load??



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BNLSergey Belomestnykh, Ilan Ben-Zvi, John Skaritka, Silvia Verdú-Andrés, Binping Xiao, Qiong Wu

CERNLuis Alberty, Rama Calaga, Ofelia Capatina, Federico Carra, Giuseppe Foffano, Norbert Kuder, Raphael Leuxe, Thierry Renaglia

SLACZenghai Li



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Thanks for your attention

Long Island Blue Claw Crabs



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Cavity mounting



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double quarter wave crab cavity helium vessel

Documents

drawing of tuning system

tuning systems helium

mhzmmduring assembly

tuning systempretuningpre

pop helium vessel

central plates efieldsilvia

us doe

volumecavity stiffening