Thin film optical coatings tailor light reflected or transmitted from an optical element in a desired way. An optical coating chamber is a complex system in which multiple subsystems operate together to fabricate such coatings. For physical vapor deposition processes, such as evaporation and sputtering, the active parts of the subsystems are located within a vacuum chamber. One example is the source system that provides vapor from which films are formed. A gas delivery subsystem may add process
