The HiLumi LHC Design Study is included in the High Luminosity LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement CRAB CAVITY WELDING Crab Cavity Project for HiLumi LHC Thierry Tardy & Paula Freijedo …J-P. Brachet, M. Garlasche, L. Giordanino, R. Leuxe, L. Prever-Loiri, Rene Claret

2 -WELDING IDENTIFICATION -STATUS & NEXT STEPS -WELDING TEST AND QUALIFICATIONS SUMMARY -ASSEMBLY PROCEDURE -OPEN QUESTIONS INDEX

3 CRAB CAVITY 3D: Welds Identification WELD 2 (x2) WELD 3 (x2) WELD 1 (x1) WELD 4 (x2) WELD 5 (x1) WELD 6 (x4) WELD 7 (x2) WELD 12 (x2) WELD 11 (x2) WELD 13 (x4) WELD 14 (x4) WELD 8 (x1) WELD 15 (x1) WELD 16 (X1) WELD 9 (X4) WELD 10 (X2)

4 SPLIT CAVITY: DRAWING LHCACFCA0023 with the one identification for each weld -Design of tooling -Perform of the Welding test -Qualification according to EN to compliance with PED (Category I) NEXT STEP: - DESIGN OF THE WELDING CONFIGURATIONS & SAMPLES FOR TESTING -SEQUENCE OF ASSEMBLY STATUS

5 Difficult Weld

6

7 -ASSEMBLY PROCEDURE

8 - OPEN QUESTIONS 1- Final thickness to weld after forming 2- Weld fit-up tolerances 3- Internal welding Quality RF: Roughness 4- Tuning Interfaces Nb-NbTi: Possible change of design to weld directly Niobium with Niobium. 5- Sequence and welding cycle crossings on both “lunettes”:  Beam difficult access  Large welding angle Option welding with backing and re-machining : Most suitable solution from EBW point of view 6- Procurement of rotatory device

9 THANKS FOR YOUR ATTENTION MERCI POUR VOTRE ATTENTION THANKS FOR YOUR ATTENTION MERCI POUR VOTRE ATTENTION

The HiLumi LHC Design Study is included in the High Luminosity LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement