Production Process of KAGRA UHV Chambers

Abstract

We have manufactured two types of ultra-high vacuum vessels for the gravitational wave observation facility KAGRA. Thirteen containers with an inner diameter of 1500 mm and three containers with an inner diameter of 1200 mm were connected using a bellows unit to achieve an installation accuracy of 2 mm and a gas release rate of 10^－8 Pa·m³ s^－1 m^－2.