Precision joining by brazing, high temperature and laser brazing on example of ion optics components of mass spectrometers for a scientific space mission (Rosetta Rosina for the ESA mission)

摘要

Different parts of a reflectron type time of flight mass spectrometer for a qualitative analysis of cometary gases were built by using the hard, laser and high temperature brazing techniques. The technical requirements for the ion body were ultra-high vacuum capability, high voltage capability and gold plated electrodes at a maximum body size of 30 mm × 45mm. In order to achieve these requirements, alumina ceramic, molybdenum and niobium were joined. The metals were joined with the laser brazing technique using titanium as brazing filler metal. Metal-alumina joints were realized with an indium-copper-silver alloy. By using a modified brazing device, geometrical and shape tolerances of less than 0.02mm were obtained throughout the ion body.