Leak Testing of Large Vacuum Vessels

Abstract

Vacuum integrity of fusion devices has become increasingly important as the size, complexity, and requirements for wall cleanliness have increased. If vacuum leaks occur during device construction or operation, it will take a long time to locate and repair the leaks. In this course of vacuum technology, methods of measuring leak rates and searching for leaks at large vacuum vessels are described. They include the conventional tracer probe (helium spray) method, the detector probe (helium sniffing) method and the in-vessel leak sensor method. Some remarks on detecting very fine leaks are also presented.