Namio Matuda

Reduction of outgassing rate of SUS316 and OFC class-1 by prebaking in a vacuum furnace: application to gravitational-wave experiments

Abstract A high performance uhv system is required for a large-scaled interferometer used for gravitational-wave experiments. Pressures of 10−6 Pa or less are necessary for its stable operation. Quick pumping is also required for frequent exposure to the atmosphere in the preliminary experiments. So materials used for very long vacuum ducts in the uhv system should have a low outgassing rate and a low gas-adsorption probability. Surface modification techniques such as high-temperature prebaking (550°C × 100 h) in the vacuum furnace and TiN coating were adopted for this purpose. Evacuation properties of the test ducts (1 m long × 0.15 m in diameter) made of SUS316 and OFC Class-1 prebaked in a vacuum furnace were investigated.