ABSTRACT
The material of construction of vacuum systems is generally hard glass or stainless steel. These materials, after adequate cleaning and processing offer the lowest outgassing rates. Glass systems are most suitable for laboratory experimental work in smaller (few liters capacity) volumes. However, one needs to employ glass-tometal seals for providing electrical connections. Stainless steel systems need to utilize flanged or union coupling joints. Most of the permanent joints in the metal system are generally inert gas arc welded or vacuum brazed. The hardware in the system is selected depending upon the degree of vacuum. Elastomer gaskets can be used for flanged joints and valves in high vacuum systems. However, bakeable hardware with soft metal gaskets is required for UHV systems.
