Hydrogen-Oxygen Vertical Brazing Furnace

A specially designed hydrogen‐oxygen vertical flame furnace was constructed for brazing together the copper pieces of the accelerator structure for Stanford's Two‐Mile Linear Electron Accelerator. To date, over 60 000 braze joints have been made without a leak appearing in any joint even though the brazed section operates at less than 10–8 Torr pressure. The accelerator structure is a disk loaded waveguide and is fabricated from precision‐machined, high purity copper cylinders and disks, each approximately 10 cm in diam. These components, with input and output coupler assemblies, are carefully stacked together with a shim of silver‐copper brazing alloy placed between each piece. When stacking is complete, a 3 m section of the accelerator structure is ready for brazing and is secured on a mandrel for transfer to the furnace. Purging gas is fed through the mandrel to the interior of the 3 m section to prevent oxidation during brazing. Also, as the section is brazed by the split ring burner of the furnace, a...