KEKCERN collaboration on SRF cavity fabrication RD Takeshi

KEK-CERN collaboration on SRF cavity fabrication R&D Takeshi DOHMAE 31 st/Oct/2017 CERN-KEK Committee, 12 th Meeting 1

Introduction • Investigation of technology for SRF cavity fabrication is mainly done by Mechanical Engineering Center (MEC) in KEK. • Our main purpose is to develop technologies for mass production of SRF cavity for ILC. üImprove yield ratio (stable quality) üReduce the cost for cavity fabrication üDevelop fabrication techniques Cooperation with STF* Cavity Fabrication Facility *STF=Superconducting Test Facility Collaboration with companies CERN-KEK Committee, 12 th Meeting 2

Cavity Fabrication Facility (CFF) Clean room 19 m x 14 m x 5 m （Height) Cleanness ISO 5 CFF Completed in July 2011 STF Chemical polishiing Press machine MEC Map of KEK Vertical lathe Surface CERN-KEK Committee, 12 th Meeting EBW inspection 3

Main equipments in CFF Chemical polishing EB welding machine （SST, Germany） Max. beam voltage: 150 k. V Servo press machine (AMADA, Japan) Max. applying force: 1500 k. N Microscope (Surface inspection) A cavity can be fabricated in KEK site combined with machine at MEC 24 th Oct. 2017, LCWS 17 CNC vertival lathe (Moriseiki, Japan) 4

Present status of CFF production • Construction of CFF is finished in 2011. • Started to fabricate 1. 3 GHz SRF cavity made of Nb. • Three 9 -cell cavity, three 3 -cell cavity and ten single-cell cavity were already fabricated. • Fabrication of two 3 -cell cavity is now ongoing. Cavities fabricated in 2017 9 -cell cavities KEK-0 KEK-1 KEK-2 CERN-KEK Committee, 12 th Meeting 5

Collaboration with EN-MME in CERN and MEC in KEK • Mechanical Engineering Center in CERN (EN-MME) also has machines and experience for fabrication of SRF cavity. • EN-MME (CERN) and MEC (KEK) decided to collaborate for investigation of cavity fabrication. Photo by CERN courier CERN-KEK Committee, 12 th Meeting 6

Exchanging program • Staff exchanging is programmed as a collaboration. üEstablish strong connection between two groups üTo learn techniques for cavity fabrication each other • Takeshi DOHMAE stayed EN-MME group for about 1 month (25 th Aug – 30 th Sep) • Thierry Tardy is staying MEC 1. 5 month (30 th Oct – 22 nd Dec) CERN-KEK Committee, 12 th Meeting 7

Report of staying at CERN • Join several project and work together. üElectron Beam Welding (EBW) of Superconducting Proton Linac (SPL) cavity üCryostatting of crab cavity üEBW of LHC spare cavity üNb spattering of cavity üLook around several facility and systems CERN-KEK Committee, 12 th Meeting 8

Advantages of each group EN-MME (CERN) • Fabrication (EBW) of complex shape cavity such as crab cavity • Larger manpower and apparatus →Concentrated studies such as material science, 3 D-printing machine • Experience in the real accelerator →Prototype of crab cavity will be inserted in SPS Crab cavity MEC/CFF (KEK) • Fabricating Nb cavity for higher accelerating gradient →Delicate treatment of inner surface • Whole view of SRF cavity →From fabricating to RF testing CERN-KEK Committee, 12 th Meeting 9

People whom I met or worked with Form & welding • Thierry Tardy • Manuel Redondas Monteserin • Paula Freijedo Menendez • Laurent Prever-Loiri • Ian Sexton • Romain Louis A Gerard Spattering • Mauro Taborelli • Guillaume Rosaz Meterial science • Stefano Sgobba • Ignacio Aviles Santillana • Konrad Eiler • Gilles Sedlbauer Quadrupole Resonator • Marco Arzeo Crab cavity • Marco Garlasche • Boguslaw Jozef Prochal • Artur Dominik Krawczyk • Manuele Narduzzi • Teddy Capelli • Kurt Artoos • Carlo Zanoni • Agnieszka Zwozniak • Gilles Favre • Thomas Yves Albert Demaziere • Fritz Motschmann • Alexandre Gerardin CERN-KEK Committee, 12 th Meeting 10

Summary • EN-MME (CERN) and MEC/CFF (KEK) both have technology of fabricating SRF cavity. • Collaboration in investigation of technology for SRF cavity fabrication was started. • Exchanging program was started. üLearn techniques each other üMake strong connection between each group Acknowledgement I especially appreciate Francesco Bertinelli (group leader of EN -MME), Akira Yamamoto and Masashi Yamanaka (group leader of MEC) for supporting this program. CERN-KEK Committee, 12 th Meeting 11