Fabrication of LHC cavities at CERN N. Valverde Alonso, G. Favre,T. Tardy, F. Pillon, R. Claret, S. Mastoura, E. Rigutto,J. Geisser

LHC Cavity 18/03/2016 N.V2 Detailed information of fabrication of LHC cavity in EDMS

HOM, Antenna and Coupler ports 18/03/2016 N.V3 Tooling for stamping the collar W1 TIG Tack welding +EB welding from inside EB weld from inside Collar shaped by spinning

Extremity flanges 18/03/2016 N.V4 Collar shaped by spinning Rough machining of the flange with extra thickness Tack EB welding from outside T1 + EB welding from outside W1 + EB welding from inside W2 W1 W2 T1

Ports and Extremity flanges 18/03/2016 N.V5 Vacuum brazing of SS flange plus Cu tubes Copper tubes, Bended and EB welded Strict tolerances before brazing Nickel plating of the flange in the brazing area Filler metal for brazing : Ø1 AgCuPd5% (Pd 287 V1-ISO 17672) Final machining after brazing

Cut-off tubes 18/03/2016 N.V6 Tooling for necking-out Polishing the elipses before necking-out

Welding the ports 18/03/2016 N.V7 EB welding from outside with a temporary copper ring inside (to be machined after welding) Tack EB welding from outside T1+ EB welding from outside W1 T1 W1 Tack welding EB welding

Welding the extremity flanges 18/03/2016 N.V8 Tack EB welding from outside T1+ EB welding from outside W1 + EB welding from inside W2 T1 W2 Weld from outside W1

Cut-offs. Problems and solutions 18/03/2016 N.V9 Non-desirable step inside that was attenuate by polishing afterwards Machining the height and the thickness at the iris After electropolishing of cut-off we have realized that there was a slope in the area of the weld between the beam flange and the cut-off. A EB weld was performed in this area to smooth the slope.

Half-cells Spinning of half-cells by Bonitempo. Machining of iris and equator thicknesses for EB welding 18/03/2016 N.V10 Non-desirable step inside that was attenuate by polishing afterwards

Preparation before EB welding Before EB welding, the oxide layer at the welding joint was removed with a scraper. 18/03/2016 N.V11

EB welding iris 18/03/2016 N.V12 Pre-Tack EB welding from outside T1+ Tack EB welding from outside T1 + EB welding from inside W1 + EB welding from inside W2 T2 T1 W2 W1 Pre-tack weld from outside T1 Tack weld from outside T2 Weld from outside W1 Weld from inside W2

EB welding Equator 18/03/2016 N.V13 Pre-Tack EB welding from outside T1+ Tack EB welding from outside T1 + EB welding from outside W1 T2 T1 W1 Weld from outside W1 The root of W1. Enough penetration and good aspect. Didn’t require welding from inside Metallography of the cross section of the weld Thanks to M. Crouvizier

EB welding second iris 18/03/2016 N.V14 Pre-Tack EB welding from outside T1+ Tack EB welding from outside T1 + EB welding from outside W1 T1 W1 T2 The root of Weld W1. Full penetration Weld from outside W1

X-Ray 18/03/2016 N.V15 X-Ray of Iris and equator Porosities at the Equator.Two of them are out of specification with a diameter of 0.6 and 0.8 mm. Ultrasonic examination situated the porosities in the middle of the thickness. (There are more or less 0.6mm of material until the porosities). Next time : pay attention to the cleaning and carry out a more energetic Weld at the equator.

Metrology Metrology report :EDMS by J.Ph. Rigaud Cavity measured in vertical with ROMER arm (+/- 0.1mm) 18/03/2016 N.V16 Total length : mm 1.1 mm ? Could be that the shrinkage is bigger or that the cavity deformed when welding The length of between the two plates during measuring was: Rod 1: mm Rod 2: mm Rod 3: mm Rod 4 : mm Welding shrinkage : Iris = 0.4 mm (0.6 mm in the overlap) Equator = 0.3 mm (0.5 mm in the overlap) To be re-checked in the next cavity

Metrology 18/03/2016 N.V17

Metrology 18/03/2016 N.V18

Metrology 18/03/2016 N.V19 Coaxiality between axe A-B and the equator is 0.9 Coaxiality between axe A-B and the iris N2 is 0.77 Coaxility between axe A-B and the iris N3 is 0.76