Abstract: In a vacuum pumping system with a plurality of sputter ion pumps the considerable reduction in its overall axial size and weight is achieved by utilizing a plurality of axially superimposed sputter ion pumps and a common magnetic circuit, which comprises a pair of external magnets located at opposite axial ends of the pumping system, one or more intermediate magnets arranged alternated with the sputter ion pumps and a ferromagnetic yoke, internally enclosing the external magnets and the one or more intermediate magnets.