FKPPL and FJPPL Joint Workshop A_RD_11: Development and Validation of Input Power Coupler for Superconducting Linacs Seoul, May 18th 2016 How to edit the title slide Upper area: Title of your talk, max. 2 rows of the defined size (55 pt) Lower area (subtitle): Conference/meeting/workshop, location, date, your name and affiliation, max. 4 rows of the defined size (32 pt) Change the partner logos or add others in the last row. Eiji KAKO, Taro KONOMI, Toshio SHISHIDO- KEK Hassan JENHANI, Stéphane BERRY, Christian ARCAMBAL, Guillaume DEVANZ - IRFU/CEA Walid KAABI, Hayg GULER- LAL/CNRS

Introduction:

Brazed warm and cold parts with internal surface copper coated Introduction: From single parts Brazed warm and cold parts with internal surface copper coated Two different ways to proceed: Process 1: To copper coat the single parts before brazing: Better copper quality & distribution control Easy setup Brazing thermal cycle impacts the RRR parameter Process 2: To braze the single parts then copper coat the entire set: Complicate copper coating process setup much effort needed to master the process: good Cu distribution + defect free surface No impact on the RRR parameter

Investigation on Process 1: Copper coating before brazing

Copper coating before brazing: Cross-section (thickness) measurements E. KAKO Cu-plating 14 mm Cu-plating 18 mm Cu-plating 3 mm Cu-plating 19 mm Cu-plating 20 mm Cu-plating 31 mm

Copper coating before brazing: RRR measurements Results (4.2K – 300K) E. KAKO Cu-plating + SUS Cu-plating samples Only SUS RRR measurement system RRR = r (300K) / r (4.2K)

Copper coating before brazing: RRR values before/after heat treatment at 800oC E. KAKO Hydrogen Furnace Vacuum Furnace Before HT Before HT After HT After HT Thickness of Cu-plating [mm] Thickness of Cu-plating [mm] Remarkable degradation of RRR was observed after HT.

Copper coating before brazing: Composition analysis of Cu-Plating E. KAKO Cu plating + Au strike Cu plating + Ni strike

Copper coating before brazing: Composition analysis of Cu-Plating Cu 12 mm Cu 16 mm Cu 29 mm E. KAKO Cu 26mm Cu 13mm Cu 9mm Cu 1mm Ni Cu 13mm Cu 9mm Cu 1mm Cu 9mm Cu 1mm Ni Ni Thickness of Cu-plating [mm]

Investigation on Process 2: Copper coating after brazing

Copper coating after brazing: Thickness distribution measurements Copper thickness distribution in the cold conductor (specif. 10μm ± 20% in the cylindrical section & 10μm ± 30% in the bellow relaxed to 10μm ± 50% ):

Copper coating after brazing: RRR measurements RRR measurements (Specif. 10<RRR<80)

Copper coating after brazing: Composition analysis of Cu-Plating-IFMIF coupler RRR before 400°C/2h treatment = 15 RRR after 400°C/2h treatment = 32 H. JENHANI

Copper coating after brazing: Visual inspection & defects detection Example of copper coating defects:  Setting qualitative and quantitative acceptation criteria: classification by defect type, dimension et number. Agreement about corrective actions and validation tests. Copper peel off Blister X 20 Pitting X 30 X 22 Circular spots Copper particle

Copper coating after brazing: Investigations on coupler finishing treatment Example of copper surface anomalies and their cure experimented on couplers or samples: Copper wool burnishing to remove brazing roll located on the antenna tip at the interface of copper bulk material and copper plating material. Scratches are eliminated are burnishing or bead blasting The lack of the copper is tolerated in particular situations Stains generated by light oxidation can be tolerated Large stains : Mechanical used methods : burnishing or bead blasting Chemical used methods: US bath + Tickopur R33 detergent Sulfamic acid for small oxidation stains (if needed) RBS T310 detergent for important oxidation Dark color on the air side of the ceramic can be sandblasted Others: Compare with the Prototype Power Couplers H. JENHANI

SS copper plated sample Copper coating after brazing: Investigations on coupler finishing treatment Ceramic wiping applied on copper plated sample: H. JENHANI Ceramic wool wiped region SS copper plated sample Ra=1.04 No Ceramic Wiping Ra=0.42 Light Ceramic Wiping More CeramicWiping Ra=0.39 Surface investigation using Confocal Microscopy (KEYENCE VK-X200): Observations with Microscope: No contamination of the surface with the ceramic wool Particle counting in ISO5 clean room: Cleaning with UP water/US bath/detergent, then particle counting  The counted particles number decrease down to zero  No cleaning issues due to the ceramic wool wiping

Conclusions: Efficient Sharing of investigations help to optimize each process to make it more mastered and thus mature for mass production. Working on improving the two process might lead to a decrease of cost of power couplers. Knowing processes weak points helps a lot to avoid extra-work and reduce the rejection rate during the manufacturing phase (saving time and money for industrial). Many other items are still to be investigated (conditioning procedure, cleaning and clean room assembly procedure optimization, decreasing the coupler fabrication cost).