This work describes the stages of manufacturing a series of radio frequency contacts (RF-contacts) for the Large Hadron Collider (LHC). The activities were carried out by ENEA Casaccia in collaboration with CECOM. The LHC, under construction near Geneva, is a machine designed for developing high-energy protons beams collision. The protons will be circulated before the impact, on a path of 27 km. The RF-con-tacts are devices placed at the interconnections along the beam path, in order to guarantee continuity to the electro magnetic shielding. They are designed to minimize electrical contact resistance between a series of sliding contact (fingers) and a fixed part. The fingers are manufactured from a thin, silver-coated copper beryllium sheet and they are supported by an oxygen-free copper flange. The sheet and flange were joined by Electron Beam Welding (EBW). The different thickness of the parts, the high thermal conductivity of copper and the joints configuration determined the choice of EBW as the only possible technology for realizing the device. EBW permits to concentrate energy in a spot with power density greater than 10 7 W/cm2, so that it can melt a small volume with high speed, useful for welding high conductivity materials. In order to draft the Preliminary Welding Procedure Specification several mock-up components were used to replicate the geometry of the different types of joints. The range of power, speed and focus allowed the welding of the components with a linear speed in a range between 1.5 and 2.1 m/min with extremely tight seams. The main issues addressed in this work have included the definition of the angle of incidence, the rise and evanescence power ramps and the beam pointing.

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