Buffer gas

A buffer gas is an inert or nonflammable gas. In the Earth's atmosphere, nitrogen acts as a buffer gas. A buffer gas adds pressure to a system and controls the speed of combustion with any oxygen present. Any inert gas such as helium, neon, or argon will serve as a buffer gas.

A buffer gas usually consists of atomically inert gases such as helium, argon, or nitrogen. Krypton, neon, and xenon are also used, primarily for lighting. In most scenarios, buffer gases are used in conjunction with other molecules for the main purpose of causing collisions with the other co-existing molecules.

Buffer gases are commonly used in many applications from high pressure discharge lamps to reduce line width of microwave transitions in alkali atoms.