Answer:
By documented He-leak tests with a sensitivity <10^-8mbarl/s.All internal components are pre-tested before installation in the vacuum jacket and finally the whole system is checked again by an integral He-leak test.
By documented He-leak tests with a sensitivity <10^-8mbarl/s.All internal components are pre-tested before installation in the vacuum jacket and finally the whole system is checked again by an integral He-leak test.