Fabrication steps Shaping of halfcells and extremities Dimensional control halfcells Welding tests Dimensional control dumbbells Extremities RF measurements Shape accuracy by CMM vs RF Trimming halfcells ID: 920956
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Slide1
1
Slide2Introduction
Why copperFabrication stepsShaping of half-cells and extremitiesDimensional control half-cellsWelding testsDimensional control dumb-bellsExtremitiesRF measurementsShape accuracy by CMM vs. RFTrimming half-cellsWelding dumb-bellsRF measurements of dumb-bellsTrimming dumb-bellsPlanningConclusion
2
Overview
Slide3Introduction
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 Copper cavity3
Slide4Why copper?
Similar mechanical propertiesGood electrical conductorLess expensive OFE Copper: 17 €/kg Niobium: 470 €/kgCopper cavity4Cu-OFE (annealed)Niobium RRR>300Young’s modulus (Gpa)122-128100-110Yield strength (Mpa)50-7050-100Elongation (%)47-5040-50
Slide5Spinning
Mtlg controlMachinningRF measurementDegreasing +CpSpinning
Machining
–
Welding
preparation
(Iris & rings)
RF
measurement
Degreasing
+Cp
Dumb
-
bell
assembly
Degreasing
+Cp
Stiffening
rings
assembly
RF
measurement
Cutting
dumb
-
bell
lengthRF measurementDegreasing+ Cp
Nb
EBW
EBW
EBW
Degreasing
+Cp
Trimming
cells
length
RF
measurement
RF
measurement
Degreasing
+Cp
HALF- CELL
DUMB-BELL
Metrology
control
Fabrication steps
Slide6Spinning
ExtrusionMachinningDegreasing + CpSS Flange-NicklingAssembly flange + bushingMachiningDegreasing
+Cp
Spinning
Extrusion
Machining
BRAZING
Brazing
Degreasing
+Cp
Machining
Degreasing
+Cp
EBW
EBW
Nickeling
Nickeling
Cu
SS
BIG FLANGE
SS
Flange
-
Nickling
Assembly
flange
+
bushing
Machining
Degreasing
+Cp
Nickeling
Nickeling
Brazing
Machining
Degreasing
+Cp
Cu
SS
SMALL FLANGES
2x
Fabrication steps
Slide7Assembly
extremities & dumbbells
EBW
RF
measurement
Cutting
cells
length
Degreasing
+Cp
Assembly
extremities
&
half
-
cell
RF
measurement
Machinning
RF
measurement
Tack
-
weld
- EBW
EBW
Tack
-
weld
- EBW
EBW
EBW
Tack
-
weld
- EBW
Tack
-
weld
- EBW
EBW
Fabrication steps
Slide8Shaping of half-cells & extremities
Half-cells & extremities8Fabrication of half-cells and extremities by spinning. Subcontracted to HeggliDimensional controlThe average shape accuracy achieved is ± 0.150 mm
Slide9Dimensional control
Copper half-cells9The average shape accuracy achieved is ± 0.150 mmThe best half cell: shape accuracy ± 0.119 mm
Dimensional control by CMM
Slide10Welding test
EB welding of two half-cells to study the welding parameters and the shrinkage of the iris weld.Copper dumb-bell10
Slide11Welding test II
EB welding of stiffening ring to dumb-bell to study the welding parameters and the welding shrinkage. Copper dumb-bell11Next step is to weld two dumb-bells by the equator
Slide12Welding test II
Copper dumb-bell12Before weldingAfter welding
Thanks to S.MARCUZZI
Shape accuracy by CMM
Dimensional control
Slide13Extremities
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.13Extremities
Slide14Rf
measurements of half-cellsMeasurement setupHalf-cells14Results on cavity simulations and measurements presentation tomorrow by S. Mikulas
Slide15Shape accuracy by CMM
vs RFHalf-cells15Shape accuracy of middle half-cellsShape accuracy by CMMShape accuracy by RFFrequency deviation MHzResults on cavity simulations and measurements presentation tomorrow by S. Mikulas
Shape accuracy mm
Slide16Trimming half-cells
Extra-length has been considered on iris (2.5 mm) and equator (5mm).Half-cells162.5 mm
5 mm
Design of central half-cell copper cavity
Slide17According to the shrinkage measured during the welding test we have machined 2.25 mm on the iris of each half-cell.
Half-cells17Trimming half-cellsTrimming of central half-cell
Slide18Welding dumb-bells
After trimming, 8 dumb-bells have been welded.Dumb-bells18
Slide19RF measurements of dumb-bells
Dumb-bells19Dumbbell measurements presentation tomorrow by N. Schwerg
Slide20Trimming 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 frequencyCompression 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. Dumb-bells20
Slide21Planning
Preliminary planning for two copper cavities21EB weldingRF measurements
Machining
Degreasing, etching
Slide22Conclusion
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.Conclusion22
Slide23FIN
Thanks for your attention!!23