ABSTRACT
Like many technical disciplines, leak detection has experienced a rapid growth since World War II. Before examining the principles and techniques of the helium mass spectrometer method, it is desirable to have an understanding of the fundamentals of leak detection. This chapter presents an introduction to the nature of leaks and the special terminology used in leak measurement, and surveys various conventional leak detection methods. It is important to avoid even extremely small leaks when constructing high- and ultrahigh-vacuum devices or process chambers. Detection, sealing, and avoidance of small leaks is also very important in production of hermetically sealed devices. The basic functions of leak detection are the location and measurement of leaks. These functions are carried out through the use of standard leak test techniques, which are usually selected according to the configuration of the part to be tested, the economics of the test, and the nature of the system.
