The ZTH high vacuum system is a modular design, where each pumping stack has a dedicated roughing system and control system interface. Eoch high-vacuum-pumping-station is electrically grounded through the vacuum liner and isolated from all other grounds. Large magnetic fields near ZTH during operation require the turbomolecular pumps to be located approximately 5-m from the center of the machine. A separate roughing system is used to rough the vessel from atmospheric pressure. The gas handling system supplies high purity gases for (1) continuous gas flow, (2) gas injection, and (3) discharge cleaning procedures. Control and interlock functions are provided by a subsystem controller' dedicated to the vacuum/gas handling systems.