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Manufacturing parameters for β=1 cavity mock-up

Nuria Valverde on behalf of the

SPL team

CERN, 8 Dec. 2011

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Introduction Why copper Fabrication steps Shaping of half-cells and extremities Dimensional control half-cells Welding tests Dimensional control dumb-bells Extremities RF measurements Shape accuracy by CMM vs. RF Trimming half-cells Welding dumb-bells RF measurements of dumb-bells Trimming dumb-bells Planning Conclusion

Ove

rvie

w

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Introduction

Two copper cavities(mock-up) are under fabrication:-To learn from the fabrication of the copper cavity for the niobium cavity. -To carry out RF measurements on the dumb-bells and complete cavity with the HOM.

-For surface treatment purposes

Copp

er

cavi

ty

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Why copper?

• Similar mechanical properties

• Good electrical conductor• Less expensive

• OFE Copper: 17 €/kg • Niobium: 470 €/kg

Copp

er

cavi

ty Cu-OFE (annealed)

Niobium RRR>300

Young’s modulus (Gpa) 122-128 100-110

Yield strength (Mpa) 50-70 50-100

Elongation (%) 47-50 40-50

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SpinningMtlg controlMachinningRF measurementDegreasing +Cp

Spinning

Machining – Welding preparation (Iris & rings)

RF measurementDegreasing

+Cp

Dumb-bell assemblyDegreasing+CpStiffening rings assemblyRF measurementCutting dumb-bell lengthRF measurementDegreasing+ Cp

Nb

EBWEBWEBWDegreasing

+Cp

Trimming cells length

RF measurement

RF measurementDegreasing

+Cp

HALF

- CEL

LDU

MB-

BELL

Metrology control

Fabrication steps

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SpinningExtrusionMachinningDegreasing + Cp

SS Flange-NicklingAssembly flange + bushingMachiningDegreasing +Cp

Spinning

Extrusion

Machining

BRAZING

Brazing

Degreasing +Cp

Machining

Degreasing +Cp

EBWEBW

Nickeling

Nickeling

Cu

SS

BIG

FLAN

GE SS Flange-NicklingAssembly flange + bushingMachiningDegreasing +Cp

Nickeling

Nickeling

Brazing

Machining

Degreasing +Cp

Cu

SS

SMAL

L FL

ANGE

S

2x

Fabrication steps

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Assembly extremities & dumbbells

EBW

RF measurement

Cutting cells length

Degreasing +Cp

Assembly extremities & half- cellRF measurementMachinningRF measurement

Tack-weld- EBW EBW

Tack-weld- EBW EBW

EBW

Tack-weld- EBW

Tack-weld- EBW EBW

Fabrication steps

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Shaping of half-cells & extremitiesH

alf-

cells

&

extr

emit

ies

Fabrication of half-cells and extremities by spinning. Subcontracted to Heggli

Dimensional controlThe average shape accuracy achieved is ± 0.150 mm

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Dimensional controlCo

pper

hal

f-ce

lls

The average shape accuracy achieved is ± 0.150 mmThe best half cell: shape accuracy ± 0.119 mm

Dimensional control by CMM

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Welding testEB welding of two half-cells to study the welding parameters and the shrinkage of the iris weld.

Copp

er d

umb-

bell

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Welding test II

EB welding of stiffening ring to dumb-bell to study the welding parameters and the welding shrinkage.

Copp

er d

umb-

bell

Next step is to weld two dumb-bells by the equator

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Welding test IICo

pper

dum

b-be

ll

Before welding After welding

Thanks to S.MARCUZZI

Shape accuracy by CMM

Dimensional control

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Extremities•Extremities fabricated in one piece by spinning and nozzle necks made by extrusion to minimize the welding distortions.•SS (316LN) Conflat flanges brazed to the copper tubes.

Extr

emit

ies

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Rf measurements of half-cells

Measurement setup

Hal

f-ce

lls

Results on cavity simulations and measurements presentation tomorrow by S. Mikulas

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Shape accuracy by CMM vs RFH

alf-

cells

Shape accuracy of middle half-cells

Shape accuracy by CMMShape accuracy by RF

Freq

uenc

y de

viati

on M

Hz

Results on cavity simulations and measurements presentation tomorrow by S. Mikulas

Shap

e ac

cura

cy m

m

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 190.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Shape accuracy by CMM vs RF

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Trimming half-cellsExtra-length has been considered on iris (2.5 mm) and equator (5mm).

Hal

f-ce

lls

2.5 mm

5 mmDesign of central half-cell copper cavity

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According to the shrinkage measured during the welding test we have machined 2.25 mm on the iris of each half-cell.

Hal

f-ce

llsTrimming half-cells

Trimming of central half-cell

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Welding dumb-bells

After trimming, 8 dumb-bells have been welded.

Dum

b-be

lls

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RF measurements of dumb-bellsD

umb-

bells

Dumbbell measurements presentation tomorrow by N. Schwerg

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Trimming dumb-bells• In order to achieve the final cavity with the right

frequency and a length within the tolerances the dumb-bells shall be trimmed at the equator to a specific length (to be calculated for each dumb-bell).– Trimming at the equator increases the frequency– Compression of the final cavity by tuning decreases the

frequency – Elongation of the final cavity by tuning increases the

frequency.

Playing with these factors we have to obtain the right frequency at the right length.

Dum

b-be

lls

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Planning

Preliminary planning for two copper cavities

EB welding

RF measurements

Machining

Degreasing, etching

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Conclusion

• Two copper cavities under fabrication. • We learn from the fabrication of copper

cavities.• Many fabrication steps will be retained for the

fabrication of the niobium cavity.• Assembly tooling of copper has been validated

and it will be used for the niobium as well.• One copper monocell β=0.65 to be fabricated

next year.

Conc

lusi

on

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FIN

Thanks for your attention!!